Mars and Me

Opportunity Sol 1075 (Spirit Sol 1096)

2012-02-01T23:10:00.000-08:00

As Steve Squyres points out, "We're falling victim to the extraordinary scenery we see before us -- flash is extremely tight." And he's looking to make cuts, and of course, one of the cuts we end up making is to reduce the quality of the ultimate and penultimate drive images, just after Ashitey made a (justified) stink about it. Oh, well.

So we're driving, but it's not a big drive, just a few meters, to get into position to do another piece of our long-baseline imaging. But because of all the tricky sequencing now required to leave useful tracks for VO in this terrain, it ends up being quite a lengthy and complicated sequence.

So much so, indeed, that Steve can't resist tweaking us about it at the walkthrough. "This has gotta be the highest sequences-to-meters-driven ratio ever," he says. "This sequence is a work of art -- this has gotta be the fanciest three-meter drive I've ever seen. This is what happens when you give the rover planners one and a half hours to go three meters."

"Back at the beginning of the mission," he continues, "we'd have done this with a single three-meter arc."

"But then your stereo baseline wouldn't be as good," Terry points out.

"And we'd have fallen over the cliff, yeah," Steve replies. "But apart from that ...."

Opportunity Sol 1074 (Spirit Sol 1094)

2012-01-30T21:51:00.000-08:00

No driving is planned today. But yesterday's drive stopped a bit earlier than we'd hoped, after covering 2.19m of the planned 2.5m, due to increasing tilt. We knew the tilt limit was tight, but we allow only 8deg of tilt this close to the rim, and our limit of 7.8deg was about as high as we'll go.

But, looking at the data ... well, I'd be comfortable commanding another 30cm at a higher tilt if it came to that. Our slip wasn't increasing, which is what the tilt rules are really about, and if anything, we'd probably actually flatten out a bit more over that distance.

The possibility is alive for a while, until Larry Soderblom comes by. "Two point one nine meters is close enough," he announces, and that's that. No driving today.

I do have to come back later in the afternoon to give a demo for the college-aged son of a friend of Charles Elachi, the Lab's director. I don't know what's happened to college kids since I was in college myself. They seem to be opening the entrance gates to younger and younger students. Pretty soon, they'll be letting kindergarten kids in.

But he's a nice guy, and appropriately enthusiastic and impressed. So I won't hold his youth against him. He's clearly wise beyond his years.

[Next post: sol 1096 (Opportunity sol 1075), February 1.]

Opportunity Sol 1071 (Spirit Sol 1091)

2012-01-27T19:53:00.000-08:00

I have good news and bad news. And good news. And bad news. And good news.

The good news is, we got satisfactory results from our VO test. Wiggle-and-scuff produced good results, so we're going to use that for our drives in this area for a while. (And indeed, it was used for yestesol's drive, which I wasn't on shift for. And it kept working.)

The bad news is, the drunken-sailor test didn't work.

But the good news is, that's due to a simple flight software bug in the command that tells the rover which arcs are allowed. And it's a bug that we can probably compensate for, so drunken-sailor isn't out of the running (or staggering) yet.

The bad news is, we can't take advantage of our success by driving thisol. We need to take PCAM images from this spot before we can move again -- they're needed for long-baseline stereo -- and we need NCAMs to target those PCAMs. And the NCAMs aren't down yet.

The good news is, the NCAMs eventually come down after all -- stuck in a pipe somewhere in the intarweb, or something. Whatever. We're driving!

Well, maybe it's a bit of a stretch to call it a drive. It's just a little 2.5m bump further along this cape. But the wheels are going to turn and they're going to take the vehicle with them; call it what you will.

The simplicity of the sequence leaves me time for chatting about an upcoming radio interview I'm doing. They've asked for the top five moments in the mission. "I've got Spirit's landing, Opportunity's landing, Spirit at the top of Husband Hill, Opportunity at Victoria ... and I'm taking suggestions for the last one," I announce.

There's no shortage of suggestions. Jake Matijevic proposes Opportunity at Endurance. "It was the first time we got to a really big crater," he says. "And it was both a scientific and an engineering accomplishment."

Ashitey has plenty of suggestions, too, and he disparages one of my choices. "Personally, I think getting to the top of Husband Hill was kind of an anti-climax," he says. "A lot of the drives we did to get there were more interesting."

"Fair enough," I counter. "But to me, getting to the top of Husband Hill wasn't the point; it's that it represents the stuff we had to do to get there." He looks half-convinced, so I press on. "It's like running a marathon. Crossing the finish line is great, but that doesn't happen without all the stuff that led up to it -- all the training, the 26 miles you had to run to get there ...." That does it. He's on board.

Julie Townsend plumps for the sol-18 anomaly. I wasn't going to include that one, mostly because I'm tired of it, but she makes a good case. "It had the whole team working together to solve a problem -- and actually, we had two rovers in crisis, with Opportunity on her way to landing right when that happened." Hmmm ... it's a good point. That one goes on the maybe list.

Then that leads us into the top five scariest moments of the mission. The sol-18 anomaly is one, of course; then there's catching a potato in Spirit's wheel, Purgatory, losing Spirit's right-front wheel with winter coming, ....

For me, one of the scariest moments of the mission is something Jake says during that discussion. I've heard it before, but not from him. "We're going to have to think about another hard decision," he says. "When to give up on Spirit."

Ashitey's response captures my feelings perfectly. "Never!" he exclaims. "We'll drive her on one wheel!"

But Jake points out that, well, budgets are being cut, and Spirit's limited mobility makes simply turning her off a possible choice.

Later in the day, John Callas (MER's project manager) stops by to see what's up, and Ashitey mentions that possibility to him.

"We're not going to sacrifice a vehicle," John says flatly. "That's not gonna happen."

And that's the best news I've had all day.

[Next post: sol 1094 (Opportunity sol 1074), January 30.]

Opportunity Sol 1066 (Spirit Sol 1087)

2012-01-23T17:14:00.000-08:00

We're in what is probably the flattest, most featureless terrain this vehicle has been in, ever. You'd think that would be good news: no obstacles, nothing to hit. The problem is that we have this big honking hole in the ground called Victoria Crater, and we need to stay the heck away from it.

Our basic tools for making sure we stay away from something are visodom and autonav. Visodom helps you by telling you where you are, by comparing "before" and "after" pictures to figure out how far the rover actually went -- as compared to how far it thinks it went because of how many times it spun its wheels. The problem with that is that in featureless terrain, the "before" and "after" pictures look the same. We try to fix that by looking at our own tracks, but those have a nice repeating pattern -- a "picket fence effect" -- that can confuse the software. Looking into the crater at the nifty featureful stuff in there doesn't work either, mostly because it's too far away.

Autonav has its own problems in this terrain. With no features, it can't get good 3-D data about the world, so it treats that as a scary lack of data. Essentially, the flat featureless stuff gets treated like a cliff. And since there is a real cliff that we want it to be scared of, we wouldn't turn that off even if we could.

Normally, for historical reasons as much as anything else, Opportunity relies on visodom. Yesterday's drive stopped due to a VO failure caused in turn by the "picket fence effect" when we looked at our highly repetitive tracks. So what do we do to fix visodom's problems here? We have to make our own tracks more interesting.

So that's the plan. We pick a direction -- a direction more or less straight away from the crater -- and plan a test. Mark has a particular idea he wants to try for the first 5m, "but after that, it's up to you," he says. Gracious SOWG chair Larry Soderblom is on board with it; I don't even need to point out that spending a sol or two to do this checkout could save us a whole bunch of sols down the line.

So here's today's drive. We plan a 25m drive, broken into five segments, each of which tries a different test:

Scuff with both front wheels on each step. As we drive backward, we periodically stop to rotate the right front wheel, then the left front wheel, away from us, in order to push up a chunk of dirt.
Same as above, but we wiggle the left wheel instead of scuffing with it. This creates a different pattern on each side.
"Drunken sailor" -- my favorite, of course, but not only for the name. This test tells the rover that it's not allowed to drive straight toward its goal; it must veer a bit to one side or the other. Since the real-world performance of the vehicle is never perfectly symmetric, this should create an interesting pattern out of little more than randomness. Plus, this version is the easiest to sequence.
Every step, do a small turn in place.
Finally, the "mother of all tests": run a step of test 1, a step of test 2, and so on down the line, until each has been done twice.

One of those oughta work. If they don't, we're screwed.

[Next post: sol 1091 (Opportunity sol 1071), January 27.]

Courtesy NASA/JPL-Caltech. Oh, my gods, is it ever flat here. Flat. Flat. Flat flat flat. Except, you know, for the giant scary hole in the ground. But otherwise, flat.

Spirit Sol 1085

2012-01-21T15:55:00.000-08:00

Ah, brilliant. We've been working on releasing a new RSVP version to go with the new Linux version we're moving to. And they decided that today would be a good day to upgrade one of the RP workstations. (Not, say, yesterday, when there was no planning on Spirit and we would have had the whole day to work out any problems.)

And, of course, we're doing a whole lot of crap today. We're doing the first RAT daisy we've done for hundreds of sols, with the usual extensive MI followup.

Yay ....

It turns out right away that something about the new installation has major problems. Applications are crashing more or less randomly, including RSVP, sometimes within seconds of being launched. It looks like some kind of weird problem with the video driver, though why this didn't show up on our development machine is a mystery for now. But the bottom line is that the newly upgraded machine is useless for real work, and we have to switch to a backup. This isn't too bad, just irritating and time-consuming.

But we get through the day, as we always do. We discover late in the game -- fortunately not too late -- that due to a silly editing mistake, I'd screwed up the calls to some of our helper sequences. So I fix that before delivering, but I feel the need to go back and obsessively check everything before we can go on. "Sorry," I say, "it's just my OCD."

"That's OK," Cindy Oda says, "I like it better when the RPs have a little bit of OCD."

"In that respect, Scott's one of the best," says Ashley.

I get no respect around here.

[Next post: sol 1087 (Opportunity sol 1066), January 23.]

Spirit Sol 1082

2012-01-18T13:56:00.000-08:00

"According to Brenda," Khaled tells me, "we're doing a tool change from MB to APXS, and that's it for the three sols."

Khaled and Brenda turn out to be right. You could say it's an easy sol.

But in our wonted way, we put the spare time to good use. At my request, Paolo has started to lay out an approach back to Tyrone, the spot where we bogged down on the way to McCool Hill. We won't be going into the scary soft stuff, but we're going to try to get close enough for the MTES to get good pictures of the unusually high-sulfur sand we churned up there. Then we'll turn around and head for Home Plate.

So we stand in front of this enormous printout of the winter panorama, and start drawing imaginary lines on it. Yeah, we could follow our old tracks here, but that would take us too close to these big rocks with a not-terribly-maneuverable rover. So we have to go this way, but we'll have to watch out so we don't anchor the wheel on this cluster of pebbles over here. We should drive to that mound, no farther, and halfway there we should assess whether to do a wide U-turn that intersects the mound or just go all the way and do a sharp turn once we're there.

That kind of thing.

Now here's a joke you really have to be on MER to get. "Hey, Rich," I say to Rich Morris. "You know how I told you you should write a song and call it the Rat Brush Jam?"

"Yeah," he laughs.

"Well, you should make up a dance to go with it, and call it the Solar Array Stomp."

The whole room cracks up.

"My joy is tainted only by my depression that I didn't think of that first," Rich says.

It would be a terrific day if it weren't for some bad news I get, confidentially, at the end. Sharon and I are talking about some rover-driving issues, and she tells me quietly something I need to know about the importance of getting things right on the Spirit drives.

"NASA HQ thinks Spirit is useless," she says bluntly. "They might shut her off in October. So it's that much more important that we have some visible successes."

Well, that's good to know.

But shut her off? Over my dead body.

[Next post: sol 1085, January 21.]

Spirit Sol 1079

2012-01-15T11:57:00.000-08:00

I haven't worked with Khaled for a while. He's in fine form, still struggling a little but well on his way to being a full RP again. Today is all IDD work, and it should give him a decent workout.

The first sol's nothing: just pick the APXS up and put it down about 1cm away. It's the second sol that causes all the trouble.

We've got three IDD targets to choose from, spread across the face of the ridge that forms part of the Troll feature. Target 1, off to the right, is the science team's preferred target, and we can reach it pretty well, though we have to disable the wheel-volume collision checks to do it. Target 2, off to the left, is at the very limit of reachability, and is in fact unreachable by the APXS. Target 3, in the middle, is easy to reach but least interesting to the scientists. So we go with Target 1.

Only we discover, partway through sequencing, something we really should have noticed at the outset. There's a projecting knob of rock to the right of Target 1, so when we put the MB on that target, the APXS nearly collides with the knob. Bloody hell. Target 3, here we come.

With that under control, I go up to the Land of Opportunity to help resolve a question raised by one of the mission managers, Rich Morris. The planned Opportunity drive uses a waydisc that's mostly inside of Victoria -- in particular, the center of the waydisc, the waypoint, is inside Victoria. Now, the rover is aimed straight at the waydisc, and it'll stop when it reaches the waydisc's edge, which happens well before it enters Victoria. But theoretically, the rover's mobility code could decide to wander far off to the side, head into Victoria, and enter the waydisc from the side.

Now, we have various guards against that happening. They've already given the rover so-called keepout zones, which are like stringing up "Police Line -- Do Not Cross" tape around the terrain. If the rover crosses the line, it'll stop, and there's no way for it to get into Victoria without crossing one of these lines. In addition, there's a set of reactive checks, where the rover will look at its tilt and suspension and freak out if it appears to be going over a cliff. And, of course, there's our years of experience driving the vehicle, which tell us that it'll do the nominal thing.

But ... a while back, as a defensive measure, I wrote up "Rules of the Rim," which are similar to the "Rules of the Road" in which we documented our best practices for driving through the etched terrain. These rules are meant to document our best practices for driving around Victoria, and one of them says not to sequence drives such that the drive could nominally go into the crater. Rich's question is, does today's planned drive violate that rule?

It's a tough call. Realistically, the answer is no. But technically, we're violating both the letter and the spirit of the rule. And, grimly, because I know this means more work for the RPs on shift -- and, in the real world, pointless work -- I have to tell the truth. Yeah, it's against the rules. And moreover, it's against the rules for a good reason. We really shouldn't do this.

Happily, Paolo Bellutta, one of the RPs on shift, comes up with an elegant fix. There's a knob you can twiddle to tell the rover that it's only allowed to drive so far toward a waypoint. This means we can turn the normal, unbounded-distance command into a command whose nominal behavior constrains the rover to a circle around its starting point. By correctly choosing this setting, we can be that much more sure the rover won't enter the crater; it puts us within the letter and spirit of the rules, and it's a low-effort change. Paolo's brilliant, and everyone's happy.

So I'm back downstairs, back to my own rover. And just in time to hear John Callas point out something I hadn't noticed, and I used to keep fairly close track of this. Today we're doing a three-sol plan, for sols 1079 through 1081. Sol 1080 will be 12 times our prime mission of 90 sols.

Every month a year long, if you see what I mean. And we just keep going.

[Next post: sol 1082, January 18.]

Spirit Sol 1073

2012-01-09T07:59:00.000-08:00

Well, let's see if we can handle this. We've got to do a tool change, swapping the APXS for the MB.

No, wait -- there's more. Before plunking down the MB, we need to swing the IDD off to one side so we can take a PCAM image. Oh, how will we ever finish in time?

Yeah. It's an easy day.

[Next post: sol 1079, January 15.]

Spirit Sol 1070

2012-01-06T06:00:00.000-08:00

"Way to go, RPs!" Oded Aharonson exclaims over the telecon. "You guys are awesome!"

We can't believe it ourselves. There's Montalva, right in the middle of the IDD workspace. Spirit ended up less than 8mm from her goal position, and she kept trying to make it until the clock ran out.

Good girl. I love this rover. Way to kick off that fourth Earth year, baby!

So, since she made it, we're going to take full advantage of her new position: whip out the IDD and start working this outcrop over. We RAT-brush it, MI it, and plant the APXS.

[Next post: sol 1073, January 9.]

Courtesy NASA/JPL-Caltech. Way to start that fourth Earth year, girl. I love you.

Spirit Sol 1069

2012-01-05T05:21:00.000-08:00

As of this sol, we're starting our fourth Earth year on Mars. For Spirit, at least; Opportunity's anniversary doesn't happen for another few weeks.

But we're celebrating it in a big way, with an aggressive drive to the Troll outcrop. Yestersol's IDD autoplace checkout got killed because it was taking too much time, but it looks like it was running OK. It just took it a little longer than expected to find targets, and when it got killed, the sequence was in the final cleanup phase anyway. So we're good to go.

But go where? The scientists would like us to go to the part of Troll nicknamed "Riquelme," but there's a slight problem with that. When you look carefully at our current position, it appears that Riquelme isn't just under the left solar panel, it's under the left middle wheel. That means we drove over it with at least that wheel, probably also with the left front wheel, and we'll drive over it even more getting away. When we do that, we contaminate the target with tracked-in dirt and also with small amounts of metal from the wheel itself, and in a case like this, that makes the target less attractive to the scientists.

So we're off to another part of the Troll outcrop, a section called Montalva. This is a low slab of exposed rock visible off to our left. As with any Spirit drive these days, this is going to be a challenge. We've got to back up while turning 100 degrees counterclockwise, then bump forward until Montalva is close enough to reach it with the arm.

Not only does this call for some fairly precise driving, it also means trying to climb a slope of maybe 12 to 14 degrees -- forward, yet, pushing one wheel. Not only that, but time is tight; if just one or two steps don't do everything they should, we'll probably fall short. It's about at the limit of what Spirit can do now, maybe over that limit, and we're careful to say so to the science team.

But I hope she makes it. That'll be a nice, quiet, but glorious way to start our fourth year here.

As another milestone, thisol we uplink r1000 -- the 1000th drive sequence sent to the vehicle. That's not the same as 1000 drives, because it's common for a single drive to use multiple sequences. But it's a cool moment to see those numbers wrap.

Spirit Sol 1068

2012-01-04T04:41:00.000-08:00

Happy New Year, everybody! It's January 3, which means that tonight at 8:35PM Pacific Time is the 3-year anniversary of Spirit's landing.

We always take care in sequencing, but never more than when we have an anniversary like this one. You don't want the story of your three-year anniversary to be that you hurt the rover -- not that you'd want that any other day, of course.

So we're particularly careful about planning the drive to Troll. Troll is an outcrop just a few meters from our Winter Haven. Currently, it's under our left solar panel, but we think we can get there -- although, with the high tau we've been experiencing lately, we're concerned that the obvious approach to Troll leaves us with an unfavorable tilt.

At least we'll be able to gather lots of data about the drive -- Spirit's got only 10.3Mbits of data on the file system, perhaps an historic low!

Except that we won't be able to do the drive after all. Not today, anyway. It turns out tau is even higher than we thought, which means we have less energy to play with than we thought. So the drive will have to wait for another day.

Instead, we're going to repeat the third step of the IDD autoplace checkout -- just another capability added in R9.2 of the rover's FSW that aims to make us rover drivers damn near obsolete.[1]

While Chris Leger -- who wrote the code for that new capability -- works on that, Ashley and Terry and I go ahead and work on the drive anyway. So what if we can't send it up? That's no reason to deprive ourselves of the fun of planning it!

The drive to Troll will be challenging for our little five-wheeled bot. We'll face a decline in our northerly tilt, from about 7.5 degrees to about 5, and that can be a lot of change for a power-starved vehicle. Moreover, as we climb the outcrop, our westerly tilt increases, which means the solar-array wakeup would happen later in the day. Furthermore, we may simply be unable to climb the slope: it's about 12 degrees, and that seems to be around the limit of what we can do now.

But Jake Matijevic OKs the power issues, so our plan will be to do what we always do: try our damndest, and find a way to make it work if humans -- and plucky robots exploring other planets -- can.

Footnotes:

[1] IDD autoplace enabled the rover to safely unstow the arm and place tools on targets that were outside the IDD's reach at the start of the drive. That is, you could drive to a target and use the IDD on it, all in one planning cycle. It was slow, but it worked. Just like us, the rovers got smarter as they got older -- but I'm pretty sure they didn't lose their glasses all the time. Damn glasses. Where did I put them?

Opportunity Sol 1045 (Spirit Sol 1063)

2011-12-30T01:23:00.000-08:00

So now Opportunity is sitting in front of a rock known as Santa Catarina, ready to IDD the heck out of it. As has happened before -- and recently, too -- the target is heavily shadowed, so our terrain mesh is poor. There's a sort of "king's crown" of mesh spikes surrounding the rock and pointing toward the FHAZ.

This makes the whole day ... well ... interesting. Hand-estimating surface normals to the target is always dicey, and it's worse when you reflect that we can break the IDD if we're off by more than 15 degrees.

So that we won't have to do this tomorrow, we also make some time for swinging the IDD away and taking another FHAZ of the IDD workspace. If only the rover had fingers she could cross.

Meanwhile, Santa Catarina itself is an interesting rock. Well, not to me, maybe, but to the science team, and that's all it takes. According to Squyres, "Santa Catarina is the first rock we've seen at Meridiani where, a, we can say something about where on Mars it came from, and b, it's not made of blueberry stuff." Good news for them, then.

Another piece of good news is that I actually see improvement in Terry's IDD sequencing. Especially on a day like today, which is plenty stressful already.

I just hope I haven't spent all my luck on that. I'm going to need some left over for the FHAZ we're taking. Especially since Opportunity can't cross her fingers.

[Next post: sol 1068, January 4.]

Courtesy NASA/JPL-Caltech. Santa Catarina, in all its heavily shadowed glory. On the next rover, I want headlights, you hear me? Headlights!

Opportunity Sol 1032 (Spirit Sol 1053)

2011-12-19T18:47:00.000-08:00

Yestersol's drive didn't go quite as planned. Opportunity drove through a small depression that increased her tilt to 7.44deg -- just above her tilt limit of 7deg -- so she stopped, which of course was the right thing to do. But she's actually fine, and ready to continue.[1]

The remainder of the drive is only about 8m, and that stops us in a perfectly safe position, about 2m from the rim. But there's a ritual now: any rim approach causes some people to panic, and after a lengthy discussion, we end up moving the final position back another 50cm. Which is how it always happens. It's just silly: we're not going to be wrong by 2m over a drive of 8m, and even if we were, we have reactive checks -- such as the tilt limit that correctly stopped us today -- that would catch our mistake before the vehicle was in danger. The 50cm pullback is just a compromise to end the discussion, nothing more.

What bugs me about this most, I think, is the fact that the extra 50cm of buffer is there not for any technical reason but to mollify the exaggerated concerns of people who aren't RPs. There, I said it. It feels good to have it said.

Tomorrow, no doubt, the ritual will be performed again.

[Next post: sol 1063 (Opportunity sol 1045), December 30.]

[1] One of the hazards of the job, I'm afraid. You always want to pick a tilt limit that's just a little higher than you think the rover will actually experience, so that an excessive tilt will mean she's strayed off course. But it doesn't always work like that: faulty data or other problems can lead you to choose a number that's lower than you should have. Fortunately, nearly all the time -- as in this case -- the problem with being overly conservative is just slight embarrassment. As long as I still have a rover to play with the next day, I can take it.

Opportunity Sol 1019 (Spirit Sol 1039)

2011-12-05T09:32:00.000-08:00

Yestersol's Opportunity drive went well, so we're not going anywhere in particular today. Mostly, we're going to sit and take pictures.

But we are doing a bit of driving. In order to optimize our downlink for the weekend, we're just going to do a comm turn.

Steve Squyres raises an interesting issue with this. Back when we developed our strategies for driving with this IDD problem, one of the things we told NASA HQ was that we'd hover-stow (a.k.a. "thinker-stow") whenever possible, mostly to minimize the risk that the IDD would fail in the stowed configuration. However, we've kind of lost sight of that, preferring to do a full stow on every drive, because it's so much easier.

It is also, in more than one respect, safer. In order to drive in the thinker-stow position, we need to ensure that we don't drive any wheel over anything bigger than 3cm. Also, we can lose calibration when we do that, because the IDD bounces around more than when it's tucked safely below the rover's chest.

What ends up putting the kibosh on thinker-stowing for the day is not any of those considerations, but one more esoteric. The rover won't drive when it thinks the IDD is not stowed, and the thinker-stow position doesn't meet the rover's definition of a stow. So you have to poke a flag that tells it to consider the IDD stowed anyway. However, the command that does that hasn't been tested under the new flight software, and the potential downsides are significant. So we don't do it. I'll have to look into the matter soon and ensure that we can thinker-stow in the new FSW, but at least for today, things stay simple.

[Next post: sol 1053 (Opportunity sol 1032), December 19.]

Spirit Sol 1037

2011-12-03T08:13:00.000-08:00

And off we go. Our big goal for the day is just to turn from a heading of 167 to a heading of 270, the first piece of our Esperanza drive. If everything goes exactly as planned, we'll end up straddling the shelf that was off to our right when we were at Winter Haven. In the best case, we'll also try to bump about 1m back along the shelf, just to see how that goes -- but if it doesn't get a chance to run due to time constraints, that'll be fine with us.

Happily, we're up to a whopping 357 W-hr. Well, that really is whopping, for Spirit these days. That number keeps climbing, and as it does, we'll be able to move more and more. And as drives like this one build our confidence, I hope we'll be able to drive more and more confidently.

[Next post: sol 1039 (Opportunity sol 1019), December 5.]

Spirit Sol 1034

2011-11-30T06:14:00.000-08:00

On the road again ....

Well, not just yet. We'll be bumping in a couple of days, exercising those weary wheels. But we want to do some MIs first, and we don't want to do IDD work and driving in the same day -- driving our five-wheeled vehicle will be plenty tough without any added distractions. So we're doing the MI today, and then we'll bump Thursday and/or Friday.

The surface we're MIing has something that looks like lapilli -- they're these little glass beads formed in volcanic ash. Whether the objects we're seeing are actually lapilli or not is an open question; that's just what they look like.

To a geologist, anyway. To John Callas, they look like peas, and that starts a whole lot of comparisons between the features we're seeing and Twinkies, pancakes, and I can't even remember what else. I think we all must be hungry!

[Next post: sol 1037, December 3.]

Spirit Sol 1032

2011-11-28T04:54:00.000-08:00

It's only sol 1026 on Mars, but we're planning sol 1032 for Spirit -- nearly a week ahead. These long APXS and MB integrations will do that.

Next week, things get more interesting on this rover: come Thursday or Friday, we'll try to drive away. We want a spot where we can see the MB "damage" from the winter campaign, and from which we can begin our attack on Esperanza.

Should be fun. But the only thing we're up to today is a MB-to-APXS tool change. And it was already done. Yesterday. By a shadow. Makes me feel damn near useless.

Can't wait for next week.

[Next post: sol 1034, November 30.]

Opportunity Sol 1009 (Spirit Sol 1029)

2011-11-25T02:56:00.000-08:00

I'm not on shift today, so I decide to run an errand and go in a little late. While I'm running the errand, my cell phone rings. It's Al Herrera.

"Hey, are you on Lab?" he asks. That's never good news.

"Nope."

"Well, uh, Ashitey was scheduled to be RP-1 today, and he's not here. And he's not answering his cell phone."

Now, that's as unusual as all get-out. "I'll be right in," I tell him. Tara -- RP-2 today -- is there, and she can hold the fort until I arrive. But I'm awfully worried. Ashitey's as reliable as they come; if he's not there, he's probably dead in a ditch. And don't think I'm kidding.

The terrain mesh is just amazing. We're perched near the rim of Victoria Crater, looking out into it, looking across the crater at another promontory. We could damn near drive over there if we wanted to, and if we thought we could somehow descend safely into the thing from here.

Instead, we'll be hauling ass in the other direction, mostly away from the crater. The plan is to make lots of progress toward our next imaging position, but to end this drive well away from the crater, to give us room to perform some more testing of the new mobility flight software. If those tests go well, we'll be able to use even more advanced autonomous hazard avoidance.

The bad news for today is that we don't have PCAM in the drive direction. So I pull out a technique we don't seem to have used on this rover in a while: autonav. It makes me feel good just to be using it again. We back away from the crater rim using VO, so that we'll know for sure when we're 5m or so away. Then we drive blind up to the limit of our mesh -- only about 10m -- and switch on autonav for another 40m or so, a total of about 60m.

Not bad at all, really: I didn't even think I would get to drive the rovers today, much less that I'd do one of the longer drives we've seen for a while. I'm almost disappointed when Ashitey shows up during the day. It turns out the whole thing was a misunderstanding: they'd originally planned no RP activities today, and when they changed their minds, Ashitey didn't get the word. So that explains that, and at least he's not dead in a ditch! Which is good news -- and what's more, since I've already invested in the day, we decide it's best for me to just complete the shift. Bonus!

One of the reasons we can afford to do such a long drive is that our energy has been creeping back up. We're now getting 560 W-hr per sol. It's enough that they suggest to Steve Squyres that this could be the sol we resume doing overnight ODY comm passes.

Steve's excited -- but skeptical. Not because he doesn't believe it, but because, as he puts it, Colette has been playing "Lucy and Charlie Brown" with him -- teasing him with the promise of an overnight pass, only to yank it away at the last second.

"So I'll believe it when I see it," he mock-pouts.

That makes it all the funnier when Colette works it out so that we can do an ODY pass, and Steve gets really excited, and then something or other changes and she has to take it away again at the last second. As usual, Steve takes it with good grace and humor. I'm sure those screams of anguish are in jest, mostly.

I almost don't want it ever to work out. This way is more fun.

[Next post: sol 1032, November 28.]

Courtesy NASA/JPL-Caltech. A small part of the view from today. Glorious!

Spirit Sol 1024

2011-11-19T23:38:00.000-08:00

Opportunity's drive stopped early; what was to be a 1.5m bump was a 1m bump. But they can see just fine from where they ended up, so they're staying there.

Spirit's drive didn't go as well as planned, either; we failed to stomp the outcrop. However, we ended up where we wanted to be, which on this vehicle is a huge success. We might try again.

But for now, we're OK with where we are, and we're up to some light IDD work: MI+APXS thisol, RAT nextersol.

Terry's the shadow today, and he needs more practice using the IDD, so I hand it over to him.

It's a long day. A long, long day.

[Next post: sol 1029 (Opportunity sol 1009), November 25 -- MSL's launch date, we hope!]

Courtesy NASA/JPL-Caltech. We might not have done everything we wanted, but we ended up in a cool place. Those platy-looking outcrops make tasty food for our robotic arm.

Opportunity Sol 1000 (Spirit Sol 1019)

2011-11-14T20:20:00.000-08:00

I called dibs on the Opportunity "Now Planning Sol 1000" sheet -- and got it. So I have the set.

Dibs is a very powerful concept.

I shouldn't actually be working today, but Sharon, who's our team chief and therefore handles the schedules (among many other things), is a woman of her word. They changed when they were going to plan sol 1000 -- that was originally scheduled to be tomorrow, but for complicated reasons they decided to plan it a day in advance, so it's getting done today. Sharon had promised me I'd get to work on sol 1000 on both rovers, so as soon as she heard about the change, she came to me to alert me to it, and see who I wanted to bump so I'd be on shift.

Jeng and Antonio were RP-1 and RP-2, and Tara was shadowing. So who did I want to bump off the list? Well, what kind of a person would I be -- what kind of a team lead would I be -- if I took away the fun of planning sol 1000 from someone else? So I had Sharon add me to the list as a second shadow.

And here I am, shadowing, as we drive Opportunity to the rim of Victoria once again. It's a short drive, and one we can do without a lot of uncertainty, using VO all the way. But certain people (Cindy Oda) have been freaking out whenever we drive up to the rim, and today is no exception.

So today I try a new approach. I start trying to compare the drive to things people can see around them. We're driving less than the width of the room we're in, a little more than the length of our conference table. I measure the size of the carpet squares; they're a little more than a half meter on a side. Walt Hoffman has a great idea: we've got a couple of 3m network cables lying around, which gives you a handy way to measure 3m (our distance from the rim), 1.5m, and 1m, at least.

I think this helps. It gives people something more concrete -- being able to say "We'd have to be wrong by the length of this 3m network cable, on a drive the length of this conference table" is pretty effective.

So everything proceeds apace. Until John Callas shows up late in the day and starts asking the same questions all over. And even that is going fine until Justin Maki -- a level-headed, bright, and valuable guy -- starts winding Callas up. "Well, what if we had two meters of range error in the NAVCAMs you're using for the drive?" Justin asks. Two meters of error? This is just absurd, and very much out of character for Justin. A realistic number for range error over that distance is maybe 8cm.

But John Callas doesn't know any of this, and it's his ass if something bad happens. So that's a painful conversation.

John Wright is listening to all this, and doesn't say much. Except, when it's all over (and we've cut the drive short another 50cm for no good goddamn reason), he tries to make me feel better about it. In his way. "Spirit's probably not going to survive another Martian winter," he points out. And he's right, we barely made it this time. "So keep Opportunity safe," he continues.

Yeah. I see his point. I mean, we were keeping her safe before, but ... yeah. I see his point.

Oh, well, we're still going to enter sol 1000 with a hell of a view. As is his wont, Jim Erickson pops by to see how things are going. "We're planning sol 1000 today!" I tell him brightly.

He looks down his nose at me, mock-snide. "Talk to me when you get to sol 10,000," he says.

Don't think I won't, Jim!

[Next post: sol 1024, November 19.]

Spirit Sol 1007

2011-11-02T12:24:00.000-07:00

It's my first day back on shift after conjunction. Both rovers weathered conjunction just fine -- maybe they don't need us as much as we think they do!

During conjunction, with the sun firmly planted between our two planets, Spirit also survived crossing the sol-1000 barrier. And I managed to snag the "Now Planning Sol 1000" sheet, and got everybody to sign it. Sweet, sweet victory. Since I'd requested to be scheduled on sol 1000, Sharon scheduled me for that day, even though there was no planning that day. I just walked around all day with a big dopey grin on my face. It'll be even sweeter when Opportunity's sol 1000 comes around in a couple of weeks.

This will be the first time we've MId Spirit's solar panels since about sol 505, apparently. Thisol is -- or, rather, these sols are, since the work executes across 1006 and 1007 -- pretty MI-heavy. Ken Herkenhoff, the MI's designer and lead, is going to be in heaven.

Meanwhile, here on Earth, not everything is going that well. Our building has a partial power outage, leaving us with nothing but emergency lighting and the glow from our monitors. I love it, actually. It's all Star Trekky. This is how things are supposed to look around here!

But there are also problems with Maestro, our planning tool, that threaten to delay the day significantly. Fortunately, our TUL, Colette, manages to get things under control, and we finish the day on time -- not with a lot of margin, but some. She's a heroine!

[Next post: sol 1019 (Opportunity sol 1000), November 14.]

Opportunity Sol 961 (Spirit Sol 982)

2011-10-07T20:55:00.000-07:00

Today we're continuing the pre-conjunction IDD activity to execute during conjunction. In one of those wonderful happy-fun-time events, there are two RAT targets -- and neither of them really works, thanks in part to wonky data in the terrain mesh caused by shadowing. We end up taking another image of the currently shadowed area, with modified image parameters that we hope will improve range data, and in the meantime we do what we can with what we have.

That turns out to be a huge pain. When at last we get something that seems to be working, we run into a joint limit on the APXS and have to start looking around for alternatives. But the alternatives that are RATtable have even worse problems, so we go back to the first target. Eventually we tweak the normal so that we can place all instruments there, but the tweaked version can't handle more than about a 10N preload from the RAT. That's not nearly enough to brush, to say nothing of grinding -- we need 40N or so. So we keep working on it ....

Eventually, we end up with a two-pronged strategy. Prong one is to choose a target in the shadowed area, despite the poor range data there. Prong two is to cross our fingers.

For the first time in a long time, there's a press conference playing on the TV behind us as we work. It's them science guys, talking about Victoria Crater. One of the images they show illustrates the scale of the crater -- they show the Rose Bowl fitting into it, with room to spare.

Wow. I see why the science team wants to stay here a while. So much to see!

[This is where we had to take a few weeks' break for solar conjunction: a giant flaming ball of gas (no, not Rush Limbaugh, the sun) interposed itself betwixt us and our beloved rovers. That made radio communication impossible for a while and thus interrupted normal planning. Next post: sol 1007, November 2.]

Courtesy NASA/JPL-Caltech. Victoria Crater swallows the Rose Bowl.

Opportunity Sol 961 (Spirit Sol 981)

2011-10-06T20:15:00.000-07:00

The drive went great. Today's all about the IDD: MI, RAT-brush, MI, APXS on the first sol; then RAT-grind, MI, and APXS again on the second sol.

Piece of cake.

Courtesy NASA/JPL-Caltech. Perfect driving put this patch of rock dead in front of us, right where we wanted it. RPs, one million; Mars, zero.

Opportunity Sol 959 (Spirit Sol 980)

2011-10-05T19:35:00.000-07:00

The drive went beautifully, or so we think. We got a nice PCAM of the slab of rock we're targeting, just 6m away. The bad news is that we didn't get the HAZCAMs for some reason. One of the other RPs floats the idea of driving even without them, prompting Steve to tease, "Are the PIs more conservative than the RPs now?" But, I say, "Nope: we don't drive without the HAZCAMs."

Steve agrees. "We drove aggressively so that we would have a margin day. Let's use it."

That becomes the default plan. But it gets under my skin. We worked hard on yestersol's drive, and it worked, damn it. I hate being stymied by something like this. So I go down to MDOT and ask them what happened to our data. Sometimes it didn't make it to the spacecraft for one reason or another, but sometimes it's just a ground processing problem of some description -- a server needs to be restarted, or something. It's worth asking, especially since I won't have anything else to do if the HAZCAMs are truly missing.

The answer from MDOT is that the data made it from Opportunity to Odyssey (our relay orbiter), but they're not sure yet what happened to it from there. It's either still on Odyssey, in which case we won't get it until tomorrow, or it's in the Odyssey TDS (the telemetry data server), in which case they might be able to figure out what's wrong and get it unstuck.

This is actually pretty good news, as far as it goes, so I take that back upstairs with me. "Change of plans," I say. "Let's plan as if there's going to be a drive. If there isn't, we'll pull it and just do remote sensing."

Then I turn to the RPs. "While we're waiting on the word from MDOT, let's see what we can do without those HAZCAMs. The burden of proof has to be on those who want to drive: we'll have to prove it's OK to drive without them. But let's bring every piece of data we have to bear on that. We've done it before, but we know we'll have to have a wider discussion -- especially since we're so close to the rim -- and we should have a case to make when that happens." They swing into action.

Man, I'm on fire.

And it turns out it's a good thing. For some reason I don't quite get straight, we lost our uplink pass tomorrow, so today is our last day to bump before conjunction. (Well, we have one more day if we absolutely need it, but we really don't want to spend that one if we don't absolutely have to, since we're not sure exactly when we lose contact with the rovers, and we want to get some IDD work in first so that we can start a long integration over conjunction.)

And then we get the word from MDOT. They found our HAZCAMs! They've been here on Earth the whole time. They've restarted the server and we should get the data in about 20 minutes.

The good news is that when the images pop out of the server, they show nothing alarming. Just as we expected -- and we can drive! The bad news is that more data pops out at the same time, and it shows an unexpectedly high current draw on the RF wheel. No telling why, and we decide there's not much we can do about it. We're driving.

The actual sequencing isn't my concern, for the most part. I'm not on shift today, just hanging out to keep an eye on things for this near-rim drive. (Ah, the responsibilities of being a lead RP!) But it's a straightforward one, appropriately simple: we drive up to a rock target ("Fogo"), bump onto it to scuff it, and then back down a bit so that we can see the scuff and IDD the rock.

(This mini-story doesn't fit anywhere, but it's a classic. While we're chatting about the sequence, my cell phone rings, playing a Smiths song, and Matt Heverly grins at me. "You're the only adult I know who has that many ring tones," he quips. "You should be a junior high kid.")

Speaking of data coming down during the process ... while we're looking at the drive during the APAM, Squyres pipes up with an interesting question. "Hey, we just got the HiRISE image of Opportunity at Victoria Crater," he announces. This is the high-resolution MRO image we've been eagerly anticipating. "Would it improve the tactical planning process if I --"

"Yes!" I declare without even thinking about it.

"Whom should I send it to?" he asks.

"Me!"

I really am on fire.

A few moments later, we're looking at Opportunity, as seen from orbit. She's sitting there, perched on Cape Verde -- just a few pixels across, and most of that mast shadow, but it's undeniably our baby. This is astonishing. It makes her real all over again. I can't even find the words.

We're going to take good care of her.

Our sequence is appropriately cautious, sporting all the bells and whistles that it should for something that takes us so close to the rim. And it helps that we're going uphill to the rim from here, so if we slip at all, it will be in the safe direction, away from the edge. But everybody's nervous about it anyway. As Matt Heverly leaves, he sums up the feeling: "Well," he says, "see you at the Congressional Anomaly Review Meeting!"

Courtesy NASA/JPL-Caltech/University of Arizona/Cornell/Ohio State University. Steve sent us a black-and-white preview of this glorious HiRISE (MRO) image showing, unbelievably, Opportunity from orbit. Click through for the full, spectacular image, available in both annotated and unannotated versions.

Opportunity Sol 958 (Spirit Sol 979)

2011-10-04T18:56:00.000-07:00

"Have you see Mark Maimone yet?" Matt Heverly asks me as I walk into the sequencing room. "He's kind of freaking out."

And he's overreacting. The drive went just about exactly as planned, leaving us poised near the rim with a beautiful view out onto Cape Verde. It's the "near the rim" part that Mark was apparently freaking out about. By the time I find him, he's calmed down, admitting that he'd misread part of the uplink report.

So if he's happy, I'm happy. Matt and I go off and plan thisol's drive, one that will take us 20m out onto Cape Verde. If this one goes well, it'll leave us set up for the final bump to our pre-conjunction imaging position. And nobody will be freaking out.

Courtesy NASA/JPL-Caltech. Peeking over the rim of Cape Verde into the interior of Victoria Crater.

Opportunity Sol 957 (Spirit Sol 978)

2011-10-03T18:16:00.000-07:00

So all we have to do is approach Cape Verde. It would help if we knew where it was: we have dueling localization estimates, and in the end we take our best guess.

Thanks to the recent flight software upload, we're nervous about using our usual waypoint commands anywhere near the crater. So we sequence a 40m shot at Cape Verde, using lower-level driving and reinforcing turns every 5m. The last 5m uses guarded motion -- it will autonomously stop if it detects a hazard, such as a cliff edge -- but otherwise there's nothing fancy.

It's gonna be a hell of a view. Victoria Crater is an awesome place, well worth the slog it took to get here.

Since we're shooting toward the crater rim, we decide to put in a few keepout zones to make doubly (actually, triply) sure we don't go in. Since circles are the easiest kind of keepout zone to specify, we put a big circle directly in our path, and two smaller ones off to the sides. I take a look from the overhead view in RSVP ... then adjust the two smaller circles slightly, and it's perfect: the Mickey Zone of Death.

Courtesy NASA/JPL-Caltech. NCAM mosaic from sol B-957. Spec-freaking-tacular.

The Mickey Zone of Death!

Opportunity Sol 943 (Spirit Sol 964)

2011-09-19T09:02:00.000-07:00

The bad news is, we're starting at 7 AM -- which means that I and the MM and TUL and SOWG chair and a few others have to start even earlier, about 6:30. The good news is, this is the last time we do that, ever. Our much-loathed 7 AM starts are now a thing of the past; no more starting before 8. Well, those of us who have to be a bit earlier will start at 7:30. But it beats 6:30, I'll tell you that.

Since I can hardly focus anyway, it's a good thing today's drive is a simple one. We plan 57m, dead at Victoria Crater, stopping midway to image a smaller crater called Kitty Clyde's Sister. This drive cuts our distance to Victoria roughly in half: we should be about 51m away when we're done.

From 108m away, the 800m-wide Victoria crater is the broadside of a barn. Even starting at 6:30 AM, we couldn't miss it with our eyes closed.

[Next post: sol 978 (Opportunity sol 957), October 3.]

Opportunity Sol 938 (Spirit Sol 958)

2011-09-13T05:04:00.000-07:00

I'm not on shift today, but this is something I couldn't leave out. As part of my investigation of the Jammerbugt anomaly, I suggested that we reinstate the practice of having the science team periodically brief the engineers on recent science findings. Today's the first installment of that, being kicked off by Steve Squyres himself.

There's way too much to summarize here -- and I didn't bother taking many notes anyway, since they were filming it -- but a couple of things stood out for me:

"Mars is a terrible place -- the average daily temperature is -60C. All the water vapor in the atmosphere would form a layer a hundredth of a millimeter thick."

and

"Meridiani and Gusev were the two best-studied places on Mars before landing. We had Odyssey, MGS, Viking data. And we had 'em both completely wrong! We expected volcanic rock at Meridiani and sedimentary layers at Gusev."

(What we found, of course, was basically the reverse. Shows the value of surface data to complement orbital data!)

[Next post: sol 964 (Opportunity sol 943), September 19.]

Opportunity Sol 931 (Spirit Sol 954)

2011-09-09T02:26:00.000-07:00

We're still not out of the dead of winter, and thus still not out of the woods. Daily energy levels aren't rising -- but they seem to have shallowed out, at least. At the same time, tau (atmospheric opacity) has spiked, and a more opaque atmosphere is bad news for solar-powered rovers.

However, tau has been on the low side lately, and is now only about average for this time of year, so it's nothing to worry about. As Oded points out, we mustn't panic about one measurement; we should wait to see if it's a sustained spike and one that causes power to drop.

And what are we going to do about it if it is rising, anyway? Go fly around with a vacuum cleaner and hoover the Martian atmosphere? No, we'll have to imitate a vacuum in another way, and just suck it up.

[Next post: sol 958 (Opportunity sol 938), September 13.]

Opportunity Sol 925 (Spirit Sol 946)

2011-08-31T21:10:00.001-07:00

Well, the tests on the IDD have gone well, and yesterday they even did real work with it. Maybe it was just a transient failure, after all.

However, we're still nervous about it, mostly because we're in for pain if it fails while we're trying to stow. During the stow and unstow process, the IDD maneuvers itself through a number of tight spaces, and getting it back out can be a real bitch. And stowing contains several small joint-1 moves, so if we didn't just have a transient failure -- if we have a real, ongoing problem -- then it's possible we'll fault out when that happens.

Fortunately, we can do something a little more active than just cross our fingers. We can walk the IDD partway through the stow process manually, at least as much as is relatively easy to sequence -- and to undo, if we get stuck. That will either build our confidence that the real thing will succeed, or tell us we shouldn't bother trying the real thing.

Happily, Eric Baumgartner left behind excellent documentation, including the exact IDD joint angles we need in order to do this test. So we look those up, put the sequence together -- and get shot down. Well, not permanently, but the SOWG chair's call is that since our doing this would put thisol's MB observation at risk, we should punt. And I can't really disagree, since we have a chance to do it again tomorrow. So we put our nearly complete sequence on the shelf, point the next day's RPs to it, and move on with the rest of the day's IDD sequencing. At least it won't be work wasted.

[Next post: sol 954 (Opportunity sol 931), September 9.]

Opportunity Sol 921 (Spirit Sol 942)

2011-08-27T18:31:00.000-07:00

Grim news from the Land of Opportunity today. The drive's off, because yestersol's IDD work on the trench failed. On the very first IDD move of the sol, we got a joint-1 stall at 80 ohms, which we haven't seen before. And the most likely interpretation of that is that the IDD has continued to degrade, and we're about to see a whole lot more failures. We might have lost the shoulder joint altogether. Jake Matijevic looks unhappy, which is never a good sign. "I'm concerned whether we'll ever be able to reliably stow again," he mutters to me sotto voce.

The only ray of hope is that the 80 ohms value isn't necessarily a magic number. It's a number we picked because it was supposed to work 90% of the time, or something like that. And if this is the first time it's failed in lots and lots of tries, maybe we just had some kind of bad luck, a purely transient failure due to ambient temperature or something. It has been particularly cold lately.

And Kirk Fleming makes a good point. "The first move of the day can be kind of sludgy," he notes as we're sitting in the fishbowl reviewing the data. "The stall doesn't seem to be resistance-related, or we wouldn't have hit the current limit. So either something else is wrong with the same actuator, or we just had a transient glitch."

Well, that is good news, and real reason for hope at last. Anyhow, we'll know more tomorrow than we do today. We're planning a test of the IDD in which we do a series of small shoulder-az motions, at increasing resistance values, until we get a success. That, of course, is hoping we do get a success, which is by no means assured at this point.

After a lot of discussion, we end up with a fairly simple scheme. We're going to repeat a test at three different times of day, so that we can test at different temperatures. Each test moves the IDD to the left and right with a rotor resistance of 80 ohms, then 90, then 100, the max we can command. If we succeed in moving it both directions at a certain resistance setting, we don't try the next-higher setting, since that's potentially dangerous.

And we'll take lots of pictures as we do it. Lots of pretty pictures. Which, we hope, will -- like the other data -- show nothing anomalous. That would leave us, perhaps, with a mystery. But given the alternatives at this point, it's a mystery I think I could live with.

[Next post: sol 946 (Opportunity sol 925), August 31.]

Opportunity Sol 919 (Spirit Sol 938)

2011-08-23T15:53:00.000-07:00

I take a personal satisfaction in today's activity: trenching with a stuck wheel.

Sure, I'd rather be high-tailing it toward Victoria. In my absence, the team got us to Beagle and beyond. Now nothing stands in our way -- well, nothing except the science team, who feel there's some science work we really need to do first.

Phooey.

The good part is that we're already prepared to do what they want to do. A few weeks before we reached the annulus, I got to thinking about that big old unknown sand sheet, and what we'd want to do once we got there. Trenching was one thing I knew they'd want to do, and I knew we hadn't done it since Opportunity's RF wheel lost the ability to steer, which makes our usual trenching sequence unworkable. So I got Paolo, Jeff Biesiadecki, and (bless his heart) Rob Sullivan to go down to the testbed and work out how to trench all over again.

Squyres said -- very, very politely -- that this was a waste of time. But I had a feeling it would prove otherwise, and it looks like I was right and he was wrong.

Well, it had to happen eventually.

So that makes the sol easy, at least: the trenching routine's already fully worked out, and we just have to send it to the spacecraft.

But you knew it wasn't going to be that simple, right? We're actually finished with the CAM when I realize what's wrong. The new trenching sequence draws a long, shallow scrape with the RF wheel, then turns slightly and makes a second scrape overlapping the first, thus broadening the trench. Now, the turn between the two scrapes is performed in an unusual way. Rather than turning through an explicitly commanded angle, which causes the rover to turn until the IMU -- roughly, her internal compass -- says it's time to stop, the mechanism used in the sequence simply runs the wheels a certain number of revolutions.

When I change this to an explicit turn for simulation purposes, the error is clear: we're turning way, way too far.

I call Paolo and confirm the problem. They worked this sequence out in the testbed, and the number of wheel revolutions to use in the turn was calculated empirically. In the testbed -- in the particular soil material in use there, in Earth gravity, and so on -- this does the right thing. On Mars, it might do the right thing, or it might turn the rover way too far.

Erk.

The change to the sequence is simple enough; we just have to replace the turn with an explicit one. I'm glad I caught this, but, boy, do I feel dumb for not catching it sooner. My first day back from England, and we're redelivering post-CAM.

Just like the old days, really.

[Next post: sol 942 (Opportunity sol 921), August 27.]

Spirit Sol 912

2011-07-27T22:44:00.000-07:00

"Aren't you gone yet?"

That's Alicia Vaughan (nee Fallacaro), asking me the same question everyone else is asking me. It's enough to make me feel unloved, or at any rate it would be if they weren't asking when I was leaving for England.

Tomorrow.

Contrary to my hopes, we obviously won't be at Victoria before I hop the pond and lose touch with all this for a few weeks. Heck, we're not even to Beagle yet. Now I have to hope they don't get anywhere interesting until I get back.

It almost makes me want to sabotage thisol's sequences, just to give myself some extra margin ....

Heck, yestersol's sequence was nearly sabotaged for me. Yestersol's RAT calibration was undermodeled, so the IDD sequence cut off at the very end. It had taken the final image, but hadn't compressed the IDD data products yet. So we didn't get those. As a result, we don't have detailed current data, but we do have a visual OK and initial conditions, and that's good enough for us to proceed. So we'll clear the errors that resulted from the premature sequence cutoff and then continue down Rob's Yellow Brick Road.

We're off to see the wizard -- and I'm off to see some Shakespeare.

[Next post: sol 938 (Opportunity sol 919), August 23.]

Opportunity Sol 890 (Spirit Sol 910)

2011-07-25T21:25:00.000-07:00

The plan for the day is to drive on toward Beagle. First, we're going to repeat the unsatisfactory scuff done on sol 885, this time recording motor/IMU data at 8Hz to better characterize the rover's interaction with the terrain. We'll take juicy color PANCAMs of it -- or just get decent-quality HAZCAMs if we can't afford the PANCAMs -- and then we press on.

We're all fired up for driving, too. Tim Parker's "Victoria Goal Map" is showing us so damn close! We're only 85m from Beagle, and 561m from Victoria. I expect we should be able to do an easy 50m or so thisol, which would put us one drive away from Beagle and cut our distance to Victoria by about 10%. I am totally jazzed about this. We've got it all worked out, and we're raring to go.

That's why I'm so disappointed when the drive is cancelled. During the SOWG meeting, the science team decides the IDD data they've gotten at this location isn't quite high enough quality, and they need one more sol before driving on.

Bummer. But at least I get a good laugh out of Rob Sullivan's description of the now-irrelevant work we did on the scuff: "a fabulous exercise in futility."

[Next post: sol 912, July 27.]

Spirit Sol 908

2011-07-23T20:06:00.000-07:00

The plan for the day starts with two 7-deep MI stacks of ripples Spirit hasn't paid too much attention to yet. The stacks are 7 images deep rather than our usual 5 because they don't want us to disturb the soil by touching it with the MB first. This is the start of a longer campaign to get MI coverage of a strip all the way between the two ripples -- a strip I soon begin to call the "Yellow Brick Road," because Rob Sullivan indicates its position with a yellow line in a planning image. The two 7-stacks are all we can afford today, but there's more in our future.

So I have what I think is a clever idea: since we know where the best focus position is likely to be, why not take a gamble? If we did five 3-stacks along the whole Yellow Brick Road, centered where the best-focus position is likely to be, then one of two things would happen. Either we'd get the best-focus images all the way along, in which case we win big, or we get enough information to work out where the best-focus position definitely is, and we come back and do a single strip of images at that best-focus position later. Either way, it's many fewer images than the planned method, and we might even get done in a single day.

Turns out, though, that this is the wrong time for the creative approach. In this case, Rob actually wants the whole 7-stack, including the out-of-focus images, because the terrain has some relief that he wants to be able to study in detail. Best-focus in one image is out-of-focus in another in a case like this. So that brilliant idea is off the table -- this time. But maybe next time.

So we get started down the Yellow Brick Road. (In keeping with the theme, I naturally push for calling our intermediate targets "Dorothy" and "Tin Man." Whee, the fun we have!) As we go along, we keep in touch with Rob, who requested this observation and is now calling in from the road on the way to a family reunion. We get to reminiscing about the nominal mission, when Rob -- one of the few who was even more hard-core than I -- practically tried to stay up 24 hours a day for the whole thing. "I used to roll from rover to rover and just pass out on the floor in the MI room," he laughs. "Hey, we should gather pictures of everyone sleeping!"

Sometimes I kind of feel sorry for the new kids -- such as Antonio, who's shadowing today -- who missed out on the overwhelming fun and excitement of the nominal mission. But at the end of the day, I overhear him on his cell phone, excitedly telling his wife that today he wrote his first sequence for the rover. The bloom isn't off the rose yet.

[Next post: sol 910 (Opportunity sol 890), July 25.]

Opportunity Sol 875 (Spirit Sol 896)

2011-07-11T12:12:00.000-07:00

So close, oh, so close to Beagle. Less than a hundred meters now. But Mars isn't making it easy for us. Around Beagle, there seems to be an earthen (marsen?) rampart, a huge wall of impenetrable ripples. As far as we can see, north to south, the darn thing is just too tall to get over.

And if we just got over this one ripple, we'd have pretty smooth sailing all the way. On the other side lies the Beagle Highway, a sizable stretch of outcrop we could follow all the way in.

Yestersol, they tried the obvious approach: just power over this damn thing. It was risky, but they were careful -- still smarting from our recent experience in Jammerbugt, very careful -- and therefore sequenced quite conservatively.

And it was a good thing they did. We ended up getting partially buried in the ripple, almost as soon as we got fully onto it. But, because of the previous RPs' conservatism, we're not so badly buried that we can't simply back downslope.

Which is our plan for the day: just back away slowly. It's a short drive, but not a short day: as someone points out, discussion = 1/distance.

Before we go too far down, though, we're going to take advantage of the fact that we're about as high up as we're going to be for a bit: we'll snap some pictures of possible alternate routes to Beagle from this relatively high vantage point. We hope they show us something good, because we haven't got a whole lot of promising routes at this point.

By which I mean, obviously: we haven't got any. We're hoping the images will show us at least one.

Of course, there's always this option: just bypass Beagle altogether, get onto the sand sheet where we can move freely, then loop around and come at Beagle from the south instead. Rampart, schmampart: treat the giant ripple as a Maginot Line.

After we're pretty much done for the day, our old pal Jim Erickson stops by for a provocative discussion. "What tools would you want to have to drive the next generation of rovers?" he asks. I think he's just giving me an opportunity to plump for using RSVP on MSL, but he's after more than that.

So far, he points out, we've basically kept single drives within a known range of terrain types. When terrain types change significantly -- e.g., when Opportunity went from flat plains to the ripple terrain -- we've been able to adapt slowly, even to the point of uplinking new flight software to deal with the terrain changes. What he wants to know now is, how can we go beyond that? How would we have to go about driving a rover if a single drive might carry it across multiple terrain types, some of which we hadn't seen yet?

Hmmm ... now that's thinking big. I think we'd want some way to recognize and categorize terrain types, then have the rover switch to different strategies based on what type of terrain it thought it was in. We'd have a collection of strategies for known terrain types; for truly novel terrain types, it might have to go around or wait for help.

That implies a lot of changes to RSVP. Time to get to work.

[Next post: sol 908, July 23.]

Spirit Sol 893

2011-07-08T10:13:00.000-07:00

It's a fairly slow day. We're just carrying out some RAT diagnostics on Spirit, picking up the IDD and posing it for a few images of the RAT before putting the MB back where we found it.

Yawn.

The IDD work we're doing will take place on sol 893 -- the second sol of a two-sol plan. On sol 892, Spirit will simply nap pretty much all day. And it'll keep getting worse for another three weeks or so, until the winter solstice. Meanwhile, we don't seem to be putting as much data into flash as we can downlink. We can't afford to -- the science observations that would fill up flash are just too costly in terms of energy.

Spirit is a sleepy basset hound, snoozing on the front porch while flies buzz around her head. I plan to work her as hard as possible when we can. But for now, we'll let her get her rest. I hope she enjoys it.

[Next post: sol 896 (Opportunity sol 875), July 11.]

Opportunity Sol 863 (Spirit Sol 882)

2011-06-27T02:58:00.000-07:00

I'm in a little early and run into Oded Aharonson, whom I haven't seen in -- well, it's been a while. He's been off in Greenland or Iceland or Norway or something, working on Cryobot, some kind of prototype ice driller they might send to Mars someday.

Which is why I haven't seen him around, of course. Being away from MER seems to have given him a certain perspective on what we're doing -- "shepherding the rovers to their death" is how he puts it. He doesn't mean it in a bad way, and I know exactly what he means, but I have to confess I'm still in denial about that. They're gonna live forever, ya know? Just a few aches and pains, is all. They're fine.

Speaking of those aches and pains ... "How are we at five-wheeled driving?" he asks. "Can we get back up onto Home Plate?"

"I doubt it."[X]

"Circumnavigate Home Plate?"

"That's more likely. Since you bring it up, what's the obsession with Home Plate, anyhow?"

Oded's always animated, but a question like that always stirs the pot. "Home Plate," he explains excitedly, "is the first time we've seen a geological feature we have a chance of explaining, a chance of forming testable hypotheses about. It's not water, but it's still interesting." Ah-hah ... looks like even Oded thinks there might be a little life left in this mission.

Though you might not know it so much by today's plan. We didn't receive sol 860's PCAMs, so we're stuck planning a drive in the NCAMs, and that limits us to about 20m. We don't have any significant IDD work, either, though we do have a bit of IDD checkout at -- oddly enough -- the end of the drive. This being Opportunity, we have our normal post-drive unstow. And after that, we stretch the IDD out a little further to check out a problem with the MB's reference channel.

This is a data stream that feeds calibration data from the MB's internal calibration target into the flight software, so that we have calibrated measurements from that instrument. For some reason, we seem to have lost that data entirely -- possibly some kind of cabling problem. All hope is not lost for that instrument, since we still can place the MB on the rover's external calibration target (just above where the IDD is stowed). But it's one more of those little aches and pains.

The rovers are fine, you know. Just fine. And they're going to stay that way, forever.

[Next post: sol 893, July 8.]

Footnotes:

[1] Wrong, of course. Didn't I know better than to bet against Spirit? The next driving season came around, and up onto Home Plate she went.

Opportunity Sol 857 (Spirit Sol 878)

2011-06-23T00:20:00.000-07:00

Sure enough, we got about 40m out of the previous drive -- not yestersol, but the sol before, since we're in restricted sols. We're now about 776m to Victoria, and only 304m to Beagle. Thisol, we're gonna step on the gas a little, and shoot for about 50m.

We've got a guest driver helping us. His name is Kelly Wills. He's spending the summer at JPL, working on an MSL task -- trying to reduce the power requirements of one of their instruments. He's from Ohio, he just graduated from high school, and he's blind.

I try to remember what I was doing the summer after I graduated from high school. I'm pretty sure it wasn't anything like that, though. And I'm not even blind.

Man, do I suck.

This somehow gets Paolo and me talking about our other, non-MER tasks. I remind him that he's not allowed to leave MER, and he assures me there's no danger of that. "There will be four people here to switch off the last workstation," he says. "Mark Maimone, Steve Squyres, you, and me."

I can't speak for the other three, but he's right about me, at least.

Speaking of Steve Squyres ... he's our friendly SOWG chair today, and something happens today that makes me suspect I'm not a complete waste of water and trace chemicals. During the B-833 anomaly investigation, it came to my attention that several of the RPs, particularly newer ones such as Paolo, had trouble standing up to pressure from the science team, particularly Steve. In my new role as the RP team lead, I urged them to stand up to this pressure, pointing out, among other things, that Steve pushes and expects you to push back when he's pushed too far -- and you shouldn't disappoint him.

So, at the APAM, Steve, smelling a long drive, says something about "putting in as many slip checks as duration allows." And Paolo says simply, "I think I will use a different philosophy: we'll use as many slip checks as we need to be safe, and we'll let the distance be what it is."

I coulda kissed him!

Oh, and speaking of water and trace chemicals .... (I really am the King of the Segues!) Steve also relates a recent science find. Concentrated calcium salts, plus zinc, plus hematite, all in one location -- the implication being, maybe, hydrothermal hot springs.

Cooool.

The other news is not so good. Opportunity's MB has lost its reference channel, which carries internal calibration data. That doesn't make the instrument useless, as we can still calibrate it against the external calibration target mounted above the IDD's stowed position. But it raises a disturbing possibility, one that Matt Heverly points out: combined with the recent transient failures we've seen when commanding the MI, it might be that we're seeing a degradation of the flex cabling that carries power and data along the IDD. If that failed, we might lose the IDD a whole lot sooner.

Fortunately, Matt came to JPL from ASI -- the company that built the IDD. And he knows the guy who was in charge of the flex cabling. "I'll shoot him an email," Matt says.

I love that. If you heard a knock coming from under the hood of your car, wouldn't you love to be able to just email the guy who built the engine?

[Next post: sol 882 (Opportunity sol 863), June 27.]

Opportunity Sol 855 (Spirit Sol 876)

2011-06-20T23:01:00.000-07:00

We're continuing to make good progress toward Victoria. Close enough to taste it, or anyway smell it. Or maybe just hear it.

Anyway, we did 40m yestersol, and we'll do 40m again thisol. This one's a little weird; we're driving up onto a sort of curb. We see these once in a while -- abrupt little steps in the terrain, usually, as here, associated with rock.

Why do they happen? I don't know, I just drive over 'em.

But not without some paranoia. The curb is at the limit of our ability to precisely measure, so after some discussion, we end up loosening the suspension limits considerably for driving over the thing. It's not implausible that we'd pop a wheelie going over it -- this happens when one of the bogie wheels (usually the leading wheel) loses purchase but its partner keeps going, as can happen when you're driving over a feature like this. The suspension auto-corrects within a meter or two, and no harm done. We wouldn't want to cut the drive in half if that happened, so we effectively tell Opportunity to just ignore it if it does.

And once again, we're plodding toward Victoria.

[Next post: sol 878 (Opportunity sol 857), June 23.]

Opportunity Sol 852 (Spirit Sol 873)

2011-06-17T21:02:00.000-07:00

Opportunity's entering restricted sols -- "a good thing, for once," as somebody points out, "since we don't have enough power to drive every sol any more anyhow."

We're losing energy, and worse, we're losing Eric Baumgartner. (I am the King of the Segues.) He's heading off to become the Dean of Engineering at Ohio Northern University. I hand him a poster we all signed for him, and shake his hand.

Eric is the kind of genius I can only wish I were. Smarter than hell, a fantastic engineer, but also great with people -- terrific social skills, a top-notch manager. And somehow he finds time to coach his kid's soccer team. It's a real loss to the Lab.

Depressed, I head downstairs to plan thisol's drive, which is a challenge. The trough before us ends in sort of a cul-de-sac about 20m away. Lying across the trough is a sort of "pitcher's mound" -- likely soft material we don't want to drive over -- and a few meters behind that is another one. Paolo wants to stop short of the first pitcher's mound, but I think we can take it, and I manage to convince him of it. Instead, we're going to drive up onto the ripple beside it, nestle in the hollow between mounds, and then scoot off into the next trough to the east. If we make it that far, we'll turn south again and back across a big patch of outcrop.

I'm either insane, or a genius. I mean, not an Eric Baumgartner genius. But a genius, anyway.

Or insane.

[Next post: sol 876 (Opportunity sol 855), June 20.]

Spirit Sol 872

2011-06-16T20:23:00.000-07:00

The bad news is, we're under 300 W-hr for the first time -- 297 is the actual number. 250, of course, is the lower limit of survivability (at least without pulling Opportunity-style Deep Sleep tricks).

The worse news is, they don't need rover drivers today. So I sit down with Tara Estlin, who's had bad luck with missing shadow shifts and stuff lately, and we work through the MI mosaic we sent last time, making sure she knows it like the back of her hand.

I'm going to have her write a simplified version of it herself, when she interrupts me. "I might need to leave a bit later," she says apologetically. "I have a sick cat ...."

Worse than merely sick, as it turns out. Tara's beloved fourteen-year-old Ripley -- the runt of the litter, but as feisty as her namesake from Alien -- is coming to the end of her days. She's got kidney problems, and she's ... she's not well. And Tara's barely keeping it together as the words tumble out of her.

Well, if there's one person around here who's going to understand about that ... I tell her about my own too-recent experiences with Jake and Zenobia, and as gently as I can, I encourage her to go home and spend some time with Ripley. I don't remember much about what I was doing at work the weeks they died, but I remember clearly the time I took off from work to spend with them toward the end. It's like gold in my hand.

"I don't know," she says, "your time is so valuable ...."

"My time is valuable," I agree quietly. "Right now, Ripley's time is even more valuable."

Tara goes home.[1]

[1] This was a hard post to revisit, having just recently lost another cat (Indiana). Life goes on, though, you know: Tara recently got another cat, whom she adores. And I know I will, too. Not yet, though. Not yet.

Spirit Sol 871

2011-06-15T19:43:00.000-07:00

We're continuing the extended RAT-brush campaign on Progress, but it hasn't been going well. For one thing, the RAT stalled again, possibly due to a pebble getting jammed in the works.

At first there's talk of blowing off the IDD work for the sol and just doing remote sensing, but cooler heads prevail. We end up doing an MI of the RAT hole, as much for engineering diagnostics as for science reasons -- if there's a pebble, we want to spot it. Then we'll image the RAT with the PCAM and FHAZ, so that if the putative pebble's lodged in the machinery, we'll have a shot at spotting it.

All in all, reasonably routine. The one thing that makes me nervous about this sequence is how close we're getting to the soil. As the RAT hole gets deeper and deeper, we move the MI in closer and closer. But since the MI mosaic that images the RAT hole also moves the MI over portions of the soil outside the RAT hole, we get closer and closer to the soil there as we go.

Our minimum standoff is normally about 17mm, but thisol it's going to be 9.5mm. Later we get updated numbers and find that it's not quite as bad as that, but it's close, at 9.85mm. That's within our 1cm error budget for the instrument positioning system, and I can't help disliking it. If you'd worked with Angry Bob[1], you wouldn't care for this, either. Imaging from the last time, when we were only about 1.5mm higher, shows that we should have acceptable clearance, so ... well ... it's one thing to be nervous, it's another to be unreasonable. I shrug and send the commands.

Footnotes:

[1] The nickname for original rover driver Bob Bonitz. If you're curious, here's the tale of his nickname (see that post's footnote).

Spirit Sol 865

2011-06-09T15:46:00.000-07:00

We're done. Or as near as damn it, anyway. We pretty much just have to pick up the sol A-857 sequence -- the one that did the last brush on our soil target, Progress -- and resend it. As usual, it turns out not to be quite that simple, but it's not much more complex, either. All around, an unusually easy sol.

So when Nicole Spanovich alerts me, I'm able to find time to remotely tell my TiVo to record Steve Squyres on the Stephen Colbert show tonight. (Gotta love that online scheduling. Magic!)

And Matt has started exploring RoSE macros.[1] He cranks out one to do the IDD safety-deactivate sequences, progressively making it more and more elaborate.

Ashley looks at him with mock pity. "He's got macro fever," she mourns.

Good. Our macros are getting a bit long in the tooth, and someone needs to work on 'em. Matt would be a great choice.

If I'm really lucky, macro fever will turn out to be contagious.

[Next post: sol 871, June 15.]

Footnotes:

[1] RoSE -- the Rover Sequence Editor, the part of our rover-commanding toolkit (RSVP) that I wrote -- has a feature called "macros," which let you kick out lots of commands for the rover with just a few clicks. I almost didn't think anyone was going to use this feature, but it turned out to be extraordinarily useful for the rover drivers in particular. Huge swaths of our IDD sequences were semi-automated through the use of macros, and later our drive sequences would be as well.

Spirit Sol 863

2011-06-07T14:27:00.000-07:00

Spirit's easy. No RPs thisol.

Spirit's interesting, too: apparently, a couple of rocks sitting very near us turn out to have a remarkably high iron content. Word on the street is, the most logical explanation is that they're iron meteorites.

Well, Opportunity found the first ever meteorite on another planet -- SpongeBob, back near the heat shield. But it's still a feather in Spirit's cap. One of many.

[Next post: sol 865, June 9.]

Opportunity Sol 836 (Spirit Sol 857)

2011-06-01T10:30:00.000-07:00

Jeng has to leave early for personal reasons. He was RP-1, I was RP-2, and Matt was shadowing, so I step in as RP-1 and Matt as RP-2. It's like a well-oiled machine.

This weekend, we had a little excitement on Opportunity: she got herself embedded in another ripple.[1] It's just like it was back at Purgatory, only not as bad: having learned our lesson from Purgatory, we had a slip check that stopped us before things got too hairy. Nevertheless, we're jammed in there pretty well, and it's going to take a bit of work to get ourselves out.

Today, we're just starting that process, commanding 5m of driving straight ahead. We'll take high-quality before-and-after pictures, along with a whole bunch of lower-res images in between. If we're lucky, we'll make about 1cm of progress. But it'll be just about the best-documented 1cm drive ever.

[Next post: sol 863, June 7.]

Courtesy NASA/JPL-Caltech. Aw, crap. Not this again.

Footnotes:

[1] This ripple was later named "Jammerbugt," after a Danish municipality, for some reason known only to Steve Squyres. I had recently been promoted to the rover driver team lead, and one of my first responsibilities was to lead the anomaly investigation into the Jammerbugt embedding.

I had lots of fun with this assignment -- my final slide included a picture of Captain Kirk ("Risk ... is our business") alongside a quote from Jim Erickson ("What I don't want to see is that we lose our nerve"). But more importantly, the investigation turned up something called the "Sullivan Asymmetry," which we named for Rob Sullivan, the science team member who noticed it and told us about it.

It turns out that the ripples were softer on one side and harder on the other, because as the Martian wind blew across them, almost always in the same direction, it deposited softer material on the leading side and harder material on the trailing side. This knowledge would help us avoid future embedding events because it meant that when in doubt, there was always a harder-packed side we could swerve toward. While that wouldn't have prevented this particular embedding (the root cause was a miscommunication between teams, and we solved that in a different way), it probably did prevent lots of future embeddings.

Oh, and one more thing about Jammerbugt. Rover driver Paolo Bellutta called it "Britney Spears Ripple" -- "Oops, I Did It Again." Funny as hell, but I decreed that we are not naming anything on Mars for that person, and that was that.

Spirit Sol 852

2011-05-27T07:12:00.000-07:00

Retract the APXS and swing the IDD away for imaging, then return and place the MB where the APXS was. Simple enough; we could do it in our sleep. But this is the third try, the first two having been frustrated by random uplink failures -- nobody's fault either time, just plain bad luck.

Theoretically, we just have to roll the sequence forward to thisol and deliver it, and we're done. But Chris and I can't help thinking up better ways to do it, and in the end we pretty much rewrite the whole thing.

Al Herrera notices the activity and perks up. "You guys just changing the sol number?"

"Nope," I admit, "we had five minutes, and thought of something else."

"Not surprised," he chuckles, and returns his attention to his laptop.

Well, the new way is better, it really is. Can I help it if Chris and I are perfectionists?

[Next post: sol 857 (Opportunity sol 836), June 1.]

Spirit Sol 842

2011-05-17T00:37:00.000-07:00

Meanwhile, back on the other side of the planet ... Spirit's been working on this lengthy IDD campaign on the soil in front of her. The other day, they tried to RAT-brush the soil (yes, really), but instead of the RAT hovering over the soil as they brushed, they apparently actually made contact.

We don't like it when stuff like that happens: the ground should be where we think it is, damn it. So today we're doing a bit of an engineering experiment, touching the soil, putting the RAT into the hover position, taking lots of images as we go. Science-free.

Since the mission started, there's been a bit of a friendly rivalry between the two rovers, particularly when it comes to total odometry. At times, Spirit's been ahead, and at other times, Opportunity's been out in front. Now, with Spirit not driving at all for six months -- and probably never driving long distances again -- Opportunity is poised to take the crown for good. As if to rub this in, Brian Cooper came downstairs and taped to the rover drivers' workstation a fortune cookie fortune he got just the other day:

NEVER LET AN OPPORTUNITY PASS YOU BY.

[Next post: sol 852, May 27.]

Opportunity Sol 814 (Spirit Sol 835)

2011-05-09T20:00:00.000-07:00

When I walk into the SOWG room, I'm startled to see Steve Squyres sitting there. Turns out he's out here so he and John Callas can meet with the NASA bigwigs about another round of funding for the mission. I wish him well, of course, and I ask, "Is it going to be harder now that Spirit's down a wheel?"

"The Spirit site is awesome!" Steve exclaims. "There's a whole class of science you can only do sitting in one place, and we've never done it at the Gusev site. No, no, we've got a great story to tell. It's just that there's only so much money to go around." And they might cut one of the rovers in order to save that money. Ulp.

He also tells me Rob Sullivan was thrilled with the MIs we took yesterday. "Rob was really, really psyched when those MIs came down -- you shoulda been there." Which is always nice to hear. Rob's a super-nice guy, and I like it when he's happy with the science we get for him.

The SOWG is over in 13 minutes -- shorter than an engineering keepout, as somebody points out -- and we're off. As we're wrapping up, everyone takes a moment to wish Steve good luck.

But Brenda's not worried. "If Steve Squyres can't get people excited about Mars, then the world is coming to an end."

"That's not the issue," Steve says modestly. "The blood's running ankle-deep at headquarters."

"Yeah," Matt Keuneke chimes in, "they'll be like, 'No funding unless you find a dinosaur bone.' And then they'll probably ask, 'How big is the bone?'"

Well, that's reassuring.

After the usual back-and-forth with Tim Parker and Matt Golombek, Paolo and I plan a 52m drive, including the autonav chunk at the end. Quite respectable progress, if it works out.

As we're wrapping up, Steve returns from the long meeting with the money men. "I went in thinking they're thinking the easy thing to do is to cut Spirit. So I hit Spirit so hard, one of the scientists asked whether we should shut down Opportunity." He grins wickedly. "Then I showed 'em Victoria Crater."

He sighs. "I expect there will be belt-tightening and cuts, but I expect we will have two rovers for the next year and a half."

That funding will have to come from somewhere, and it might end up coming from one of the other Mars missions. Steve offers his opinions on where that cut should be, should it absolutely have to be made. "If it were up to me and I had to cut one, I'd cut the U.S. participation in Mars Express. MEX can live without us. Then I'd cut MGS. MGS is not that great, with just the one camera working -- Odyssey can do everything MGS can, plus -- but MGS is doing great science and MOC is a great camera, and it would be a shame to lose any of it."

[Next post: sol 842, May 17.]

Opportunity Sol 811 (Spirit Sol 832)

2011-05-06T18:02:00.000-07:00

At the end of the SOWG meeting, I point out to the whole team what I was able to mention to only a few people yesterday: that we're now up to sol 810 on Opportunity, fully nine times our nominal mission. And there is much rejoicing -- applause and cheers on the audio net.

The drive went beautifully, just perfect. We're perched on the side of the ripple just as we'd hoped. Only problem: there's no visible banding.

Well, it's barely visible if you stretch the images juuust right. But apparently this is something that disappears up close; it's a lot more visible if you look off to either side, along the ripple. That's a weird effect. It's plainly some sort of optical illusion, but I have no idea what causes it.

The bad thing about being perched on the ripple like this is that we took an energy hit, our available energy dropping from somewhere around 440 W-hr to about 386 W-hr, due, apparently, to the 10 degrees of unfavorable tilt we picked up.

Anyway, we're here, and we're going to IDD this thing. While Jeng plans the drive -- a surprisingly aggressive 40 meters -- I work out the IDD sequence. It's unusual for an IDD sequence, a 1x10 mosaic -- basically a vertical column of images all the way down the face. Since the local ripple surface is so uniform, the sequence ends up being nice and clean; I'm quite proud of it. And I hope it works.

[Next post: sol 835 (Opportunity sol 814), May 9.]

Opportunity Sol 810 (Spirit Sol 831)

2011-05-05T17:22:00.000-07:00

I wasn't on shift yestersol, Paolo and Matt were, but they called in me and Jeng to give them some advice on driving in an area where we lacked good imaging. Our advice was to suck it up and use autonav. They did, reluctantly -- but it turned out that autonav got us within about 50cm of where we wanted to go, plenty close enough, and we're ready for more.

(Incidentally, when was the first time we had two RPs on shift neither of whom was from the original set? (I tend to think of Jeng and Ashitey as originals, though strictly speaking they weren't.) It wasn't yesterday, surely, but I don't know when it was. Ah, I'm such an old-timer now.)

But we're not going to charge down the trench, going for distance. Instead, we're going to try to address a question that the scientists have been kicking around for a while: what causes the banding we're seeing on these ripples? It looks as though there are several sets of ripples, one atop another, with slightly different albedos -- and what would cause that?

To try to find out, we're going to drive up on one and plant the MI on it. That's a slightly scary and just plain odd thing to do; we normally try to avoid these ripples, not climb them. But it's all for science, you know. So it's game on.

I'm RP-1, and Matt's shadowing me today. Since he's come up to speed on the driving (so to speak) impressively fast, I decide to hand him the reins and see how he does as RP-1. The short version is that he does great, planning a very nice approach where we scoot about 17m down the trench, then turn and charge right up onto the ripple. There's a bit of concern about whether we're going to hit the ripple in our post-drive IDD deploy, but then we realize that the ripple's only about 21cm tall, so the IDD would stay completely above it even if we were buried up to our wheels in the thing.

To make things more complex, though, we have very strict limits on our comm headings. If we're about 3 degrees off one way, we'll get a paltry 23 kilobits -- that's kilobits -- and if we're about 3 degrees off the other way, we'll be at a heading where the PMA will prevent us from talking to Earth at all, so we'll get nothing. Fortunately, ripples are broad, and we should be able to hit it spot on.

Though outwardly cool, Matt confesses he's not completely confident -- "I'm not gonna sleep tonight," as he puts it -- and while that's a feeling I know well, I have a lot of optimism about this drive. As long as we don't end up stuck in the ripple, and we've taken good precautions against that, it should be like hitting the broad side of a barn.

Should be. At least, that's what I'll tell myself when I'm trying to sleep tonight.

It's not until we've wrapped up for the sol, and I'm back in the office talking to someone, that I realize we overlooked something important. I literally run back upstairs to the Opportunity sequencing room, hoping other people will still be there.

Luckily for me, there are several people who haven't left yet, so there's someone to tell. "We just planned sol 810!" I exclaim. "That's nine times the nominal mission! How did we miss that?"

Opportunity Sol 807 (Spirit Sol 828)

2011-05-02T15:24:00.000-07:00

We don't have much drive time thisol, so it's going to be a short one. We'll retract the IDD, then drive about 30m across one ripple and up to the next (almost nonexistent) one before we'll more or less run out of time.

And that's how we'll start down the Goodnight-Loving trail. No, I am not making that name up: it's the actual name of an Old West cattle trail, in keeping with our practice of naming our Victoria-bound drives in that fashion. But I can't help getting the adolescent giggles over this name, and I make a couple of jokes about it in the uplink report. ("And finally, on behalf of all the rover planners, I'd like to welcome all of y'all to the Good Night Lovin' trail. Oh, yeah." It's funnier when you read it like Barry White.)

[Next post: sol 831 (Opportunity sol 810), May 5.]

Opportunity Sol 804 (Spirit Sol 825)

2011-04-29T13:25:00.000-07:00

I think this is the first time I've done IDD work on Opportunity -- other than the post-drive stow and unstow, that is -- for something like six months, when she had the IDD anomaly to start with. Not much IDD work has been done at all, in fact, and I'm somewhat out of the loop. And today's not just a simple tool placement, it's the whole MI/RAT/MB/APXS/MI/MB campaign over three sols, and I'm RP-1.

So I load up the sequences from the previous time we did IDD work, a couple of weeks ago, and start looking through them. They have a couple of features that surprise me. Last I heard, we were keeping the joint-1 rotor resistance to 58 ohms unless we had a fault; these sequences are using 80 ohms for almost everything except the RAT placement, which uses 75. And last I heard, the shoulder azimuth joint was supposed to stay in a range of about five or 10 degrees from the center so that the arm would be relatively decently positioned in case we lost the shoulder-az joint entirely, but these go to about 25 degrees from the center.

Clearly, I'm not up to speed here. Paolo (who's RP-2 today and is as confused as I) has the right suggestion: go ask Ashitey.

We do that, and Ashitey puts it to us like this: they're working on the extended-extended-extended-extended (or whatever we're up to now) mission proposal, and they want to include a picture of Victoria Crater in it. They don't want to blow a whole lot of sols on the way there, so they've gone ahead and raised the joint-1 rotor resistance limit to ensure that the IDD does not fault out.

I understand this, and of course I'd like to get renewed funding. But, as I point out to Ashitey, if we destroy the arm because we set the resistance value inappropriately high, we'll lose a whole lot of sols. He grins -- it's clear he had the same argument and lost it, and if he lost it, I have no hope. But I decide to try anyway, which means talking to Jake Matijevic.

When I talk to Jake, I decide I really just want one question answered. I put it to him bluntly: "Is this a safety risk to the hardware?"

He shrugs. "We probably don't really need to raise the rotor resistance from 58 ohms at all; if anything, we've seen a possible indication of some recoupling in the motor windings." That would mean we'd need only the nominal amount of current; we could reset the rotor resistance back to its nominal value of 29 ohms and the IDD would work fine -- at least, while the winding was connected. "But is there a risk to the vehicle? No, not really."

He also says it's fine to move the azimuth out of the 5-10-degree band. ("Whatever science wants," are his exact words.) I have enormous respect for Jake and for his knowledge of the spacecraft, and if that's what he tells me, I'm going to believe it. So we go ahead with that. I'm keeping my fingers crossed, just the same, though.

The sequencing itself is a bit tricky but not terribly bad. Some of it I can copy from the stuff they did two weeks ago, which helps. I'm surprised to find that I'm a little rusty, but it all starts coming back to me.

Since this is a multi-sol plan -- 804, 805, and 806 -- we have to have our usual worry about what happens if one (or more) of the sols' IDD sequences is not activated. Obviously, there's no risk to Opportunity's safety if the 806's IDD sequence doesn't make it. If 805's sequence doesn't make it, we'll be OK, since 806 starts with a tool-change command that will do the right thing whether 805's sequence ran or not.

But if 804's sequence doesn't make it ... huh. We've always been protected against the first sol's sequence's not running by the fact that we need to unstow on that sol; if we're not unstowed, the other IDD commands are smart enough not to do anything at all. But since we're unstowing at the end of every Opportunity drive now, there's no such protection any more.

So Paolo and I have to take a careful look at it. After a great deal of to-and-fro-ing, we work out that we're just fine as it stands. The IDD is at the ready position, with the turret held just in front of the vehicle, APXS pointing forward and slightly down. Both sols 805 and 806 begin with a tool change command that will first retract the active tool -- the APXS, as it happens -- 13cm. But in its current configuration, if the rover tries to retract the IDD 13cm, the IDD would collide with the body. The rover's smart enough to know this, and it would refuse to execute that or any subsequent IDD motion command until the fault was explicitly cleared from Earth.

Thus, we're fine, and we can rest easy. With our fingers crossed.

[Next post: sol 828 (Opportunity sol 807), May 2.]

Opportunity Sol 800 (Spirit Sol 822)

2011-04-26T11:27:00.000-07:00

It's sol EIGHT FREAKING HUNDRED on Opportunity today. (Somewhere in there, by the way, they used the target name "Fort Scott" -- a stop on one of the Old West trails -- and I missed it! Darn!) Eight hundred sols, and we're still driving -- and driving, and driving. We've just come out of restricted sols, and the plan for at least the next four sols is to drive every sol.

Which is just fine with me and Jeng. So we plan your basic 50m drive, composed of about 30m of eastward traverse (including two ripple crossings) and then a southward segment with autonav.

We also spend some time discussing Jeng's "RP Lessons Learned" assignment. This was a terrific idea by Chris Leger to identify a bunch of past sols where we'd screwed something up, and set the sequences in front of the newer RPs (each of them paired with a more experienced RP) and make them figure out what we'd done wrong. And, for extra added bonus evil, they then have to present what they learned to the whole IST team. The idea is to increase their general skill level, as well as making them more paranoid. It seems to be working.

Jeng's not really a new RP -- not like Ashley or Matt -- but he got his share of sols anyway, and I was paired with him. And one of his sols was the Mazatzal approach.

Oh, yes, the Mazatzal approach. As if I could forget. I've been feeling terrible about it for two years now.

I feel a little better when I see Jeng struggling to figure out what's wrong with it. It's not schadenfreude, it's just that I realize now how tough it actually was. The problems are subtle ones. First, we misjudged the amount of slip we were likely to see. Second, we aimed for a position where we'd just be able to reach the Mazatzal features of interest -- but since we knew we'd slip, we should have commanded the rover to go farther, so that we'd tend to slip toward the edge of reachability but maybe not out of it.

Just seeing that Jeng is having this much trouble -- and he's got a lot of experience now -- starts to heal that old wound a bit. And when we talk about it and he sees the problems, he makes me feel even better. "That was tough!" he exclaims. "And back then, we couldn't use visodom because of that bogus update on Opportunity. Without a way for the rover to correct for slip, how were you supposed to get this?" He shakes his head. "You should give yourself more credit."

It's nice to realize that in two years, I have learned to give myself more credit. And I think I'll take his advice and practice the skill now. That won't go into the presentation, but it might be the most important lesson this RP has learned.

[Next post: sol 825 (Opportunity sol 804), April 29.]

Spirit Sol 821

2011-04-25T10:47:00.000-07:00

John Wright and I show up to drive Spirit today, but she's just taking pictures. No IDD, and -- just as will be the case for most of the next six months or so -- no driving.

So we leave.

Spirit Sol 817

2011-04-21T08:09:00.000-07:00

It's a slow day. We're planning two sols of IDD work today -- 817 and 819 -- but they couldn't be much simpler. One's just a tool change from the APXS to the MB, and the other retracts the MB and swings it in so that it's out of the PCAM FOV.

Plus, I already wrote them, a couple of days ago. So all that remains is for me to turn this into a training opportunity, watching Terry laboriously rewrite them, from scratch.

John Callas alerts me that we have visitors -- a passel of Indonesian legislators in the tow of Congressman Dreyer -- but since they don't speak much English and are foreign nationals from a "designated country" anyway, they don't come by the sequencing area. I never even see them.

I'm not really sure they were ever there. Maybe it was just some kind of practical joke Callas was playing on me, and it went over my head.

[Next post: sol 821, April 25.]

Spirit Sol 811

2011-04-15T04:12:00.000-07:00

The LTP guy is driving Alicia Vaughan crazy. His slides abbreviate "PANCAM" as "PC," and he pronounces "ODY" -- Odyssey -- as "oddy." She giggles and rolls her eyes when he does this. "New guy," she groans.

We don't have much to do today, just a tool change from APXS to MB, and Ashitey and I decide to make Terry (shadowing us today) do it. So we have even less to do.

But we do have a Spirit Drive Meeting to go to. Our goal is to figure out what we can, and should, do about driving during the winter.

It very rapidly starts to look like the answer is: nothing. We need to gain 5-6 degrees of tilt in order to get a 15W-h power increase. It's doubtful we could do that, and anyway we think we don't need to: the current 10.7-degree tilt is believed to be survivable, though not with much room to spare.

Unfortunately, the current IDD work volume is "not very exciting," as Squyres laments. There are layered rocks and vesicular basalt nearby, either of which would be better -- indeed, we could reach the layered stuff just by turning clockwise, something we definitely can do. And it's appealing on other levels: we'd be facing south, with the solar panels aimed north, which is gives us less shadowing, is better for science, and improves our HGA comm. The problem is that our UHF comm will be poor, and since we relay heavily on that -- even more during the power-poor winter months -- that consideration will probably trump all the others.

The rules we decide to adopt are that any drive must:

Be in the best interest of survival.
Improve comm for the winter.
Improve our solar tilt.
Improve science.
Include a contingency plan to return to safety in case the drive doesn't work out.

We might be willing to relax these constraints, but they're pretty discouraging when you look at them. There are a lot of ways to make things worse, and not many ways to make them better. So we're likely just to sit here, take lots of pretty pictures, and do a little IDD work. And wait for spring.

At least Spirit's IDD is working in the meantime. I'd forgotten about this until Ashley reminds me, but one of the possible explanations for our poor rover's lame wheel was that some circuitry had failed on board -- and it so happens that one of the possible failures was one that would have taken the IDD with it.

See what I mean? There are lots of ways things could be worse.

[Next post: sol 817, April 21.]

Opportunity Sol 789 (Spirit Sol 809)

2011-04-13T02:53:00.000-07:00

Results from the previous drive were ... well ... suboptimal. And confusing, to boot. Opportunity detected excessive slip when climbing the first ripple, so we only made a few meters of progress. The confusing part is, we set her max allowed slip to 70%, and none of her reported slip numbers appeared to exceed that value. So we sort of know why she stopped, but not exactly.

While Matt looks into that, I survey the current state of the rover. The maximum reported slip numbers were still higher than they should have been, and we want to know whether it's safe to continue. Flying around for a while in RSVP, plus looking at the telemetry, clears things up nicely: we're just barely over the crest. In fact, when I look carefully at the rear HAZCAM and brighten the shadowed areas way up, I can just make out the crest of the ripple running right in front of our rear wheels. Another few cm and we'll be completely on the downhill side.

Foo. Well, the four wheels we can see aren't dug in, and the slip check turns out to have failed because of buggy -- well, let's say surprising -- behavior in the flight software that makes visodom slip checks generally more conservative than we thought they'd be. We told it to stop at 70% slip, but it was actually using a threshold of something like 52% when it stopped. So we're safe to continue, and that's what we do.

We don't go quite the same path as we'd picked out previously, though. It occurs to me today that our plan was to drive about 20m through small, but soft, transverse ripples, then hop a regular old ripple at a not particularly wide saddle point. In other words, after about 20m of picking up an unknown amount of slip, we're going to aim for a small target. And if we miss, we could have another Purgatory on our hands.

When I put it to myself in those terms, I can see what a bad idea it was all along. We could use visodom to compensate, but then we'd run out of time before we even got to the ripple, so that's pointless. Instead, I shoot for a few meters farther down the trough, where I can put a juicy patch of outcrop right in the IDD work volume. That's what Steve wants anyhow -- a little outcrop to IDD for the weekend -- and since it's the safest thing to do anyway, I'm happy to oblige.

[Next post: sol 811, April 15.]

Opportunity Sol 787 (Spirit Sol 807)

2011-04-11T01:34:00.000-07:00

Autonav worked, and it worked great. We came this close to making it all the way to the autonav waypoint, putting a total of 58.97m on the wheels. More important than the extra dozen meters or so, of course, is that it's back in everyone's consciousness. Also, now we can truthfully say we've proved it works, and we can use it again.

But today won't be the day. Today's drive is a fairly complex one, involving not one but two ripple crossings. We hop a nearby ripple, zoom down the trough for about 25m, and then hop another ripple onto a patch of outcrop at the far end-- total, about 35m. Jeng's RP-1, and he basically works out the whole thing.

Which leaves me with just one thing to do: take the credit.

I mean, assuming it works.

[Next post: sol 809 (Opportunity sol 789), April 13.]

Opportunity Sol 785 (Spirit Sol 805)

2011-04-09T00:15:00.000-07:00

Our previous drive went splendidly, gaining us about 57m toward Vickie (my little nickname for Victoria Crater). This leaves us an estimated 1603m from Victoria. During the SOWG meeting, I do the math, and am able to announce a milestone. A literal one, at that: "We're about 1603m from Victoria Crater, and a mile is 1609m -- so we're less than a mile away!"

Applause, applause.

(Speaking of the SOWG meeting, our SOWG chair today is none other than Steve Squyres himself. The last time Squyres was SOWG chair on this rover was somewhere in the 400s, back when we were in Endurance. I will try not to interpret this as some kind of hint that he lacks faith in Spirit.)

The big question of the day is just how far we're going to go. The next trough over (to the east) is more appealing than the one we're in, so we'll hop into it. Well along it -- 45m from our starting point -- is a small patch of outcrop. We can reach that without much trouble, and we can do so with considerable time to spare.

Then what? The most appealing option is another patch of outcrop 20m beyond that (65m from here), but I don't think we can reach it. There's a big mound -- a transverse ripple, I think -- just past the 45m outcrop. It's too big for us to go over and wide enough that we don't have room to go around.

Off to the other side -- to the east -- is another patch of outcrop. This one's only 58m from our starting point, so it's less appealing than the 65m patch (though it does let us go a bit eastward, which is something we try to do when we can, since Vickie's a bit east of south). However, between us and it is a bit of a step, or a slope.

The likely reason for that, judging by what we've always seen in this terrain, is simply that it's a perfectly safe, shallow slope that we can't quite see from here. However, we can't prove it's not a dangerous step.

Now, as it happens, we have a tool in our toolbox for just such occasions -- autonav! We haven't used autonav on this rover much since Purgatory. Frank and I had just reintroduced it and used it for a few drives, when Opportunity's IDD started failing. Since then, it hasn't been used at all.

But Frank and I are on shift together today, and, well ... autonav it is!

I honestly don't care whether we make a whole lot of distance on the autonav segment. What really matters is that we will have done it, and can start incorporating it into Opportunity's drives again. If she even takes a step or two on autonav, that will be a roaring success.

I also introduce another innovation today. For a long time, we've wanted RoSE to indent IF statements in our sequences, so that you could see the sequence structure more clearly as you wrote and walked through them. I got around to writing this code at last, figured out a way to backport it from the development branch to the installed branch, and took advantage of a scheme I worked out some time ago to dynamically apply the patch to the running (installed) version. I do that for the first time today, and wait to see how long it takes Frank to notice.

It takes him about, oh, I'd say, all of five seconds. Then we get another idea: we decide to have him running with that patch during the walkthrough, and we'll see if anyone notices.

Frank loves this idea, so we do it. All I can think about during the walkthrough is when somebody will notice -- but nobody says anything. I'm quite disappointed. But then, as Frank's wrapping up, Saina says, "Is this the first day using the new RoSE?" From the reactions around the room, it's clear she's not the only one who noticed. (But, amusingly, Julie didn't, and Frank comically refuses to point it out to her. "You've got to see it for yourself," he shrugs.)

"Yeah, this is the first time we've used it."

"Is it tested?" she asks.

In unison, Frank and I answer, "It is now!"

"Back when Jim was mission manager, you think he woulda let us get away with that?" Frank asks me rhetorically. "Times have changed."

They sure have. Back then, we wouldn't have tried to get away with that.

[Next post: sol 807 (Opportunity Sol 787), April 11.]

Opportunity Sol 782 (Spirit Sol 803)

2011-04-06T22:56:00.000-07:00

Saina's leaving the project. That sucks so bad, I can't even tell you.

I can't blame her; she's a mechanical engineer, and she wants to build stuff. But she's so great at ops, I'll really miss her.

"I think they want me to build the cap part of the aeroshell," she says.

I point out that this means she'll be designing the part of the spacecraft that gets to Mars first, and her face lights up. No way she's coming back to MER ops now.

Idiot.

Today's my first shift driving with Matt Heverly since he started working solo RP-2 shifts. And we've got an interesting one. The end of our current trough is in sight, and as we stare at the images, we start to realize there's nowhere we can safely hop to the next ripple between here and the end.

Unless ....

When I look down at the nearby edge of the images, just off our left side, it looks like the ripple sort of curves out, like an opened gate. A review of our HAZCAMs and the previous sol's images confirms this; there's a low spot almost dead in front of us. We just have to scoot a bit forward, then back across the ripple at a low point and we can head down our neighbor trough just dandy.

So that, of course, is what we do.

As of the start of today's drive, we're about 1660m from Victoria Crater. Put another way, that's only two Victoria-Crater diameters from Victoria Crater itself. And counting.

[Next post: sol 805 (Opportunity sol 785), April 9.]

Opportunity Sol 780 (Spirit Sol 801)

2011-04-04T21:37:00.000-07:00

Opportunity's schedule will be late for the rest of the week; we're driving every day, and we're not starting until noon or later. So I'll pretty much be in heaven. Since we're devoted to driving this week, we're keeping the science lean; next week we enter restricted sols and the scientists can have their turn again. But for now, the SOWG meetings are short and sweet. This one is over in something like 20 minutes -- not a record, but not too far off.

Downstairs, our sister has good news: Spirit's dragged herself out of the muck. She followed her tracks back out, and while the HAZCAMs show a bit of the white stuff near her new tracks, they also show she's back to making good progress.

Naturally, the next question is, now what? Word is that they've given up on McCool and have decided instead to head for a ridge to the south, which we passed coming in. It's not as far away as Home Plate (or McCool) and not as scientifically interesting as McCool, but we think we can get there, and it has slopes we think we can survive on.

So that's good.

But according to Brenda, the news is not altogether rosy. "John [Wright] thinks we're seeing the last and final days of Spirit," she mourns. "I don't think I want him driving my rover if that's the case."

Well, maybe I'll have to give him a nice pep talk. Meanwhile, I've got my own rover to drive, or anyway, to watch Jeng drive. Thisol's drive couldn't be much more boring -- we could practically do it with a single waypoint -- but I don't mind that now and then.

For one thing, it gives me time to slip out for an interview. Some British guy named Barney is doing a piece for a British engineering association -- I gather it's something like the ACM or the IEEE. They're concerned that British kids aren't sufficiently interested in science and engineering, and they want him to make a video to get the kids hyped up about it.

So I meet him in the von Karman museum, and I get there early enough to watch him do the interview before mine. It's with a very nice and articulate Brazilian scientist we have working here -- Rosalie something, I think, is her name; I've never met her before. If I didn't know better, I'd swear the interviewer guy was kind of hitting on her afterward.

Anyway, then it's my turn. The guy asks me a couple of warmup questions while his two-man crew -- they're brothers -- rearrange the lights so they can shoot me with the rover model in the background. The interview itself seems to go really, really fast, and I don't think I'm at my best, but both he and Natalie (the press office lady who arranged to get me for the interview) are really positive about it, so who knows. I'll see if I can get them to send me a DVD of it, and then maybe I can evaluate it for myself.

I want to stay and watch the presentation that's just starting next door, in the auditorium. It's a couple of teachers from New Hampshire who have worked the rovers into their curriculum. They have their students build LEGO (Mindstorms?) rovers and drive them around in a simulated Martian landscape. I had some great teachers, don't get me wrong, but why couldn't I have had a couple like that?

But I don't have time, so with unaccustomed regret, I trudge back over to the sequencing room. (Okay, it's not that bad!) I'm there for about half an hour when Saina says something about wanting to go to the LEGO talk later this afternoon.

"Later this afternoon? No, it's going on now -- you're missing it," I tell her.

"What?!" she exclaims.

A couple of minutes later, we're all heading over there together to watch what's left of their presentation. It helps to have a mission manager who likes LEGO.

The bad news is, we miss the LEGO part of the presentation. The good news is, they give us a copy -- and accept our invitation to come by the sequencing room and see the real thing. So I give them my usual demo -- which I do flawlessly, best one I've ever done -- and Jeng shows them the cool 3-D glasses, and they're digging us and we're digging them, and it's all a big group hug thing. But in a good way.

[Next post: sol 803 (Opportunity sol 782), April 6.]

Spirit Sol 800

2011-04-03T20:57:00.000-07:00

I'm not on shift today, but we have a critical decision to make for Spirit's future, so I show up at a 7:00 pre-SOWG meeting to help make it.

I help Ashitey put the finishing touches on a presentation for the meeting. The downlink isn't promising. We couldn't get onto the berm -- we turned but couldn't drive; deja vu -- and the far side of the island contains slopes we can't cross any more anyhow, so the direct path to McCool is out. The question is whether to take the scenic route we imaged yesterday; take a different, more northerly route; or back out all the way to Home Plate.

The meeting proper is all bad news. There's no new thinking on Home Plate; it remains probably out of reach and likely useless even if we could get there. As for the other two routes, nobody's done enough analysis of the imagery yet to make a decision. But since we have to back out to where we were on sol 781 before we can try either path anyway, that gives us a couple of sols or so to do the analysis. And we'll know more then than we know now.

Around the time we're reaching this decision, Steve Ruff chimes in. "Hey, if this is the closest we're going to get to McCool Hill, we should stop a couple of days and take some PCAM and MTES imaging." It's as if the guy's in a different meeting. We're desperate -- Squyres puts our odds of surviving this at fifty-fifty, and Chris Leger thinks that's optimistic. We need every erg of energy, and every second of time, to get to safety. And this guy's talking about blowing a couple of days on science? Squyres shoots him down -- but only with difficulty; Ruff is persistent.

After the meeting, Oded tries gamely to defend Ruff's proposal, saying it's not as absurd as it sounds. "If you're gonna die, there's the question of what you do first. Do you leave these questions unanswered, or ...."

"You try to get out of the burning house," Chris Leger says flatly.

Which is pretty much how I feel about it. If we really give Spirit up for dead, that'll be the time to consider how to spend her final hours. Personally, I want her to go down fighting -- it's how she'd want it. And we're not even that far gone yet. Not yet.

I make this point, in a different way, just before the meeting ends. Oded asks, as usual, "Anything else?" And I grab a mike.

"I just want to point something out." I look around at the tired, grim people in the room, and I know there are more like them listening on the telecon. This is a team that's in the process of giving up, and I can't stand it. "I just want to point out that we're here today planning sol eight hundred of our ninety-sol mission." Everybody laughs. Somehow this fact had almost escaped everyone. "Maybe so many of these sols with double-aughts have gone by that familiarity has bred contempt. But the fact that we've made it this far is a hell of an achievement. Whatever the future holds, we and this rover have done a lot of impossible things before. And all we're talking about here is doing one more."

It's not everything I wanted to say, or everything I wish I had said, but maybe it's enough. All of a sudden everyone's laughing and cheering and applauding, and the mood is quite different.

Will it last? Will it matter? I don't know. But when they make a movie of this mission -- I mean, another movie -- they'll include this moment in it, I guarantee.

Maybe they'll get Tom Hanks to play me.

Spirit Sol 797

2011-03-31T17:59:00.000-07:00

Our Spirit drives keep doing the same thing: we can execute the turns just fine, but when we start to move, we bog down pretty quickly. That happened again as we tried once again to power up this slope.

"Slope," ha! It's about four degrees of tilt. But this, combined with the soft, loose soil under our wheels, is too much for poor gimpy Spirit now.

The only nearby patch of ground that looks at all promising is a berm about 60deg off to one side of us, starting about 3m away. Obviously, we already know how to aim toward it, and we're going to try to haul ourselves up onto it if we do so.

But then what? When we look at the images, it looks like this berm is the near edge of a sort of island of possibly navigable -- hard-packed, sometimes gravelly -- material rising out of a sea of soft sand. The island is maybe 15 to 20m across, so that's great. The problem is what to do when we get to the far side, where the sand sea resumes?

If we're lucky, it's flatter over there and we'll be able to drag ourselves across it. If we're unlucky, we're just going to pull ourselves out of this frying pan, only to walk straight into that fire.

We could tell whether it's worth even trying, if only we had PCAM coverage of that area. But we don't, and the NCAM range data runs out just before that region starts.

On the other hand, if we don't go there, where can we go? Back to Home Plate? We already think that's hopeless -- even if we made it there, there's nowhere safe to park for the winter.[1] Our only other option would be a strategic retreat; reverse course for 10m or so, then take the "scenic route" along a lengthy path that circumnavigates the shore of the sandy sea.

This depends on some critical assumptions. First, that we can in fact back out. If we're really mired down here, we might not be able to do even that. And second, it depends on the assumption that the scenic route even exists. We don't have good imaging of that area, so maybe there are showstoppers. What we can see of either end of that route suggests we'll have to navigate for tens of meters around rover-killing rocks, with a rover that doesn't steer very well.

My gut feeling is that we're going to have to sound retreat. And if we're going to do that, we're going to have to do it now. Jake Matijevic says we've got about two weeks in which we can tolerate the occasional drive that leaves us with poor northerly or even small southerly tilts.

We can't do it now now, as in today, of course; since we don't know the scenic route exists, we don't know that retreating toward it does us any good. So for today we go with what we know: we'll try to drag ourselves up onto the nearby berm, but we'll also take pictures of the far side of the island and of the scenic route. That way, when we get our downlink, we'll know what we need to do.

If we get onto the berm and the imaging shows the sea on the far side of the island is flat enough, we'll try to continue directly toward McCool Hill. If we can prove the existence of the scenic route, we'll try to take it.

And if neither one pans out -- well, better not to think about that.

[Next post: sol 800, April 3.]

Footnotes:

[1] False. Indeed, that's exactly where we spent the next winter, hanging off the north side of Home Plate. But we didn't know about that area then.

Opportunity Sol 774 (Spirit Sol 795)

2011-03-29T16:40:00.000-07:00

Yestersol's drive went splendidly. We made 61m of progress, the longest single-sol Opportunity drive since Purgatory. And that puts us over 400m from Olympia.

And thisol, we're poised to do another solid one. The trough we're in peters out after another 40m, but Jeng, who's RP-1 today, finds a spot where we can hop one ripple and then skate southward along outcrop (backward), a total of about 50m.

The next drive should be challenging. After this drive, we'll be in front of a dune that's probably about 20cm or larger -- bigger than we should attempt to climb -- and we're not sure whether the eastward path around it, or the westward path, will work. Or neither, in which case some creativity might be required. But I won't be there to solve it -- I'm descending to the Spirit World tomorrow, to try to drag Opportunity's crippled sister a few more meters toward safety.

[Next post: sol 797, March 31.]

Opportunity Sol 773 (Spirit Sol 794)

2011-03-28T16:00:00.000-07:00

Good thing you don't get some kind of Martian jet lag when you head from one side of the planet to another. After my Saturday spent trying to coax Spirit a few more meters toward safety, I'm back on Opportunity today (Monday). I'm still not used to Opportunity's being the rover that's in relatively good shape, but so she is.

And we're going to be making use of it. Opportunity goes into restricted sols next Wednesday, so this week we're driving as much as possible -- seven of the next nine sols will be drive sols, everything but Friday and Sunday.

We've been making good progress so far. It's revealed at the SOWG meeting that we're already 345m south of Olympia, a good chunk of the more than 2km we had to make when we started. Something like 1.8km remains, and today we're going to bite off another hunk of that.

Unless Matt Golombek and Tim Parker talk us out of it, that is. They've apparently been taking another look at the orbital maps and think we should head more east than south at this point. But in a little while, they come by and basically do the scientific equivalent of a shrug. Either path ends up being equally likely to be problematic at some point, they tell us. So we go with the locally easy path, the best choice we can make in a position like that.

This is a slightly zig-zaggy course almost due south -- a total drive distance of about 60m, with about 50m of that being actual progress toward Victoria. If it succeeds, I expect this will be one of the longest single drives we accomplish on the way, unless we think up some new tricks over the next couple of months.

Meanwhile, the news from Spirit is pretty good. She managed to turn herself in the direction of her next waypoint and, as a bonus, made a couple of meters' progress toward it. The only bad thing about that was her reason for stopping: too much slip. We told her to stop if she saw more than 70% slip, and she saw increasing slip values that peaked at 71%, at which point she dutifully stopped.

There's very little mystery about why this happened. When we drag one wheel, it simply digs in and builds up material as we drag it. When the RF wheel was functioning but flaky, we'd use a 90-10 duty cycle -- drag it 90cm, then run it for 10cm to drive it up onto the pile of material it would accumulate. But since we can't drive that wheel at all any more, we can't do that trick. We're going to have to come up with something -- and by "we," I mean Ashitey and Chris, since they're reportedly in the testbed, trying to figure this out.

What can I say? I wish them luck. And I wish I could help in a more tangible way than that. I'll be back on Spirit Wednesday, so I might get the chance. But for now, I've got my own little horsie to worry about.

Spirit Sol 792

2011-03-26T14:41:00.000-07:00

ODY's back, and to try to make up for lost time, we're in here sequencing on Saturday for the first time since -- well -- it's been a while. We're even planning two sols. With Spirit's precarious energy situation, we're driving on alternate sols, and using the intermediate sols simply to recharge. I was like that when I was recovering from cancer: I'd walk a little, and then have to stop to breathe a while. I didn't like it, and I'm sure she doesn't, either. Poor thing; she was so healthy, so recently.

The good news is, we have data from Spirit at last! And a lot of it, too -- a whopping 110 Mbits!

The bad news is, she's not telling us what we want to hear. Our last drive was supposed to turn about 85deg and then head off toward a waypoint 10m away. It turned about 8deg and then failed. Worse, we can't deduce why it failed, because despite the size of the pass, we're missing some crucial data.

In addition, while the other wheels are doing just fine, the RF wheel is now about halfway dug into the fluffy soil we're perched on. Clearly, we need a change of technique, and we need to get a move on.

Why did the last drive fail? While we're missing some of the details, the picture starts to emerge. Our only good technique for turning Spirit now involves making use of the fact that the failed RF wheel acts like an anchor: if you simply drive forward, she pirouettes clockwise around that wheel. So they were trying to use that, alternately pushing forward to change our heading and then backing up to try to get away from the hole this technique makes. It seems that we were unable to perform the backups -- the wheel was acting as an anchor then, too. So we'd spin clockwise just fine, but when we tried to back up, we just twisted back the other way.

If only we still had a rover wakeup song -- we could play "The Twist." Or maybe that would be bad luck.

Anyway, Ashitey thinks he knows how to fix this; we're going to use a variant of the same technique, but change how we do the backups. I also come up with a way to build a slip check into the backup, so that we'll be able to tell if we're actually getting ourselves out of the hole or not; if we're stuck, we'll at least stop making the situation worse.

Naturally, all the analysis and tricky sequencing takes some time, so newly promoted project manager John Callas goes out to buy us all Subway. "But we have to see the drive animation before the rover drivers can eat," he warns.

Ashitey's a bit grumpy today, so I try teasing him to lighten the mood. "I can't believe you're letting them get away with 1-bit-per-pixel ultimate imaging, Ashitey." He's notorious for pushing for higher-quality imaging than that.

"I just don't have the energy any more," he chuckles.

"You and Spirit both! You need to get to a north-facing slope, man."

[Next post: sol 794 (Opportunity sol 773), March 28.]

Opportunity Sol 768 (Spirit Sol 789)

2011-03-23T12:43:00.000-07:00

I'm RP-1, so I get in about half an hour early -- 07:30. Turns out I needn't have bothered. As I'm walking in, Emily's telling folks on the telecon that ODY's in safe mode. That means we didn't get any data from the pass.

Indeed, we haven't heard from Opportunity at all for about 24 hours, because we didn't get a beep acknowledging yesterday's uplink. That's not terribly unusual, though it would be an odd coincidence that it happened at more or less the same time as ODY went into safe mode. Still, nobody seems able to think of a plausible connection between those two events, so a coincidence may be all it is.

We're left with three likely possibilities, ranked in descending order of goodness:

Opportunity is healthy. The drive went fine, we just didn't hear the beep that said she heard us.
Opportunity's healthy, but we didn't get a beep because she didn't get our uplink. So she didn't drive, but she's fine.
Opportunity underwent a FSW reset and is now in automode.

#3 is actually more likely than #2, as spacecraft resets have been more common than missed uplinks. Still, the top candidate is #1, and there's no reason to panic.

Assuming Opportunity is indeed healthy, we at least won't have to ask her to retransmit any data. ODY entered safe mode about an hour before our uplink, and the uplink is two-way -- she doesn't just beam a signal into the air and hope someone's listening, she has to actually get a confirmation that ODY is there before sending the data. So when she talks to us next, she'll know just what we want to hear, without having to be told. She's smart.

The plan for today is basically to ping Opportunity. We'll command a DTE comm window for sometime around 12:00 her time, which will be something like 20:00 our time, and she'll talk to us. I don't know how much data we'll get, but I think it'll be at most something like 40 Mbits, which will be plenty for health assessment but might or might not be enough to support a drive. (We could work within a 40 Mbit limit, but we generated about 60 Mbits because that's what ODY was supposed to relay, and that's how much Opportunity will send.) We always prioritize our drive-related data pretty well, though, so even if we don't get all the data we'd wanted, we'll probably be able to do something.

They consider asking Opportunity to do more than talk to us -- we could have her do some untargeted remote sensing as well. The problem is that we don't know she's not in automode, or why she entered that mode if she did, so the less we ask her to do, the better.

ODY plans to be down for at least several days; they hope to resume UHF relay Saturday. In the meantime, we've got a rover to drive, and DTE really won't cut it in the long term. So Emily also wants to investigate using an MGS relay. But as our TDLs, Kirk and Bill, tell her, something's messed up with the hardware or software involved in the MGS relay, something that corrupts data pretty badly.

"Corrupted data would be better than no data, right?" she asks.

"The last time we tried an MGS relay, we got something like 60 Mbits, of which about 2 Mbits was usable," Kirk replies.

"Oh," says Emily.

No MGS relay is planned.

What with trying to track all of this, it almost doesn't even occur to me that the loss of the ODY relay is very bad news for Spirit. Spirit can't afford to lose drive sols, and she's going to lose two or three of them -- maybe more -- over just this. We can't even command her at all before tomorrow, because there's no uplink window scheduled until then -- she won't be listening. And she still has something like 65-90m to go (depending on whom you ask) before she reaches a safe haven. The perfect storm continues to gather strength, I fear.

They don't need me at the (very brief) SOWG meeting, but I sit through it anyway, just in case. Afterward, I listen to Albert Haldemann and Tim Parker discussing the latest results from Mars. Albert mentions that the rovers have taken enough observations that they're now able to confidently predict what a dust-free sky on Mars would look like.

"Blue-black," he says. "In the daytime, you'd probably be able to see the stars."

I want Spirit to make it to the safety of McCool Hill. But if she doesn't, I hope she gets one last glimpse of those stars before she goes. It sounds glorious.

[Next post: sol 792, March 26.]

Opportunity Sol 766 (Spirit Sol 787)

2011-03-21T11:24:00.000-07:00

Our 50m drive went just as we'd planned. (Well, so it turned out to be only about 49m. That's fine.) And we're set up for another decent drive, this time probably only about 30-35m. We'll probably have a lot of these drives, just plodding along, hopping ripples and seeking friendly patches of outcrop as we go.

We're just about exactly 2km from Victoria now, which makes it about 66 drive sols away at 30m per drive sol, or 40 drive sols away at 50m per drive sol. The real answer's probably somewhere in there -- likely on the low end, I'm sorry to say, since there will be some sols in which we make little direct progress for one reason or another. And, of course, that's drive sols, not total sols -- we can't drive every sol. So it'll be a while before we get to see Victoria Crater (or "Vicky," as I like to call her).

Moreover, harshing the buzz we got from our strong progress, Tim Parker and Matt Golombek come by to tell us they think we went in the wrong direction. They show us a high-resolution map of the area and point out where they think we went down a route that will present us with less outcrop and bigger ripples, which of course is exactly the opposite of what we want. They think we should have headed more easterly on our last drive. This is the conversation Tim and Frank were having Friday, only Tim never came by and showed us the map, so we didn't realize what his objection was.

I honestly don't think the situation's as bad as they paint it. In any event, we're able to spot a trail of outcrop that's somewhat comparable to the one they'd have had us take, so I think we'll be okay.

Later, some other stuff begins to come to a head, some stuff I haven't been writing about. A while back, I chose to spend most of my time driving the rovers rather than working on RoSE, and that's set in motion a chain of events that looks like it's going to end with JPL's defunding RoSE -- spending gobs of money to replace it with something else, which if they're lucky will be as good. With RoSE goes my easiest path into the world of MSL, which might mean there's no more rover driving for me after the MER rovers die. Worse yet, I might, depending on the results of a conversation I'll have with my section manager tomorrow morning, be moved into a different section, under a group supervisor who today showed all but open hostility to me. (Which is not just my opinion; it's shared by the other participant in the conversation.)

I find this very depressing. The rovers are breaking down, and so, it feels, is my life. Or, at least, my job -- I don't really make the distinction. And maybe that's the problem.

Well, whatever tomorrow holds, today they paid me money to drive a Mars rover. Life can't be all bad if it has that in it.

[Next post: sol 789 (Opportunity sol 768), March 23.]

Opportunity Sol 765 (Spirit Sol 784)

2011-03-18T09:25:00.000-07:00

We're continuing naming stuff according to a Western theme. Right now it's stops along the Chisholm Trail, and one of those, it turns out, is Fort Scott. I desperately want them to choose this name, and they're on the verge of doing so -- but unfortunately, they change their minds. They've already used names from stops farther along the trail, and don't want to go out of order. Whether this means they'll come back and use it or not, I don't know. I only know I'm disappointed. How cool would that have been?

Well, I'll just have to derive my joy from someplace else. It's not hard to find something: Frank and I think we can get about 50m out of this drive, another strong sol if we can do it. Truth is, it won't be all that hard: follow a trough, skate along some outcrop, rack up the meters.

Our planned path is basically south, but Tim Parker thinks we should head a different direction. He's got a route picked out that would take us east, and we consider it carefully. The good part is, it would be an even longer drive -- maybe 70m. The bad part is, it doesn't take us directly toward Victoria Crater. There's a huge, apparently mostly flat annulus around Victoria, and our plan is to head south and hit that. It looks like the stuff we were cruising across back in the days of 200m sols, so we're thinking that once we're there, we can zoom across it to Victoria in no time. Anything south, or a bit east of south, drops us into that zone, so we don't see the point of heading east at a slower pace now.

So it's a 50m drive thisol, not a 70m drive -- but it's taking us directly where we want to go.

The relatively good news on Opportunity contrasts sharply with the persistently grim news from Spirit. A bunch of people filter in from the latest anomaly meeting, and they're looking pretty glum. Alicia says the participants split into two camps. Chris Leger's faction said we needed to stand down, go into the testbed, and figure out how to drive with only the remaining five wheels. Jake Matijevic's faction responded that we didn't have time to stand down and figure it out -- we need to drive, and drive now, or we're dead. Alicia notes that Spirit seems to have hit a perfect storm -- "We were late getting started, and then this happened, and winter's coming, and we can't climb, and we're going into restricted sols ...." she trails off, shaking her head sadly.

"I know," Frank commiserates. "I've never seen Chris so down about the rover's prospects as he is now."

To stave off the effects of restricted sols for a time, the Spirit team is going to Mars time for a while -- maybe just a week. Mentioning Mars time recalls memories of days gone by, and soon the anecdotes are flying. The most astonishing one comes from Julie, who was so deep into cruise ops for Opportunity, she says, that she didn't hear about the original Spirit anomaly -- when we lost touch with her for a while on sol 18 -- until it was over.

And I thought I was always the last one to hear about these things.

[Next post: sol 787 (Opportunity sol 766), March 21.]

Opportunity Sol 762 (Spirit Sol 782)

2011-03-16T08:06:00.000-07:00

Our last drive went well, gaining us about 33m of the 2km or so toward Victoria. Well, the journey of a thousand meters begins with a single arc, or something like that.

Anyway, the trough (or "half-pipe" as some are calling them now) that we're in continues -- we've got plenty of room. There's another easy 35m in front of us, and when Jeng and I look carefully at the data, we each conclude we can go a lot farther. Initially, we're thinking of going about 70m, though we end up cutting back to 50m. What's particularly annoying about this is that we had to cut back on the PCAM quality because there simply wasn't room in the downlink, and if we hadn't had to do that, we'd likely have been able to do a 70m drive thisol. We do throw in a bit of bonus driving with guarded arcs at the end, which will eat up drive time in case it's as safe out there as we suspect it is, but this won't add more than about 5m to our total.

Still, 50m is good; we won't get a lot of chances at drives like this, and we should take 'em when we can get 'em. Might as well get ahead of our drive metric while we can. The scientists will want us to stop and fiddle around with something pointlessly soon enough. And as I try to remind everybody, we used to spit on a 30m sol. I guess we'll never go back to the days of 200m sols, now that we need to stow and unstow around the drives, but we should push it as far and as fast as we can.

Did I say stow and unstow? In keeping with our new Western theme, we have new nomenclature: we no longer stow and unstow the IDD, we now holster and draw it.

We should have been saying that all along.

[Next post: sol 765 (Opportunity sol 784), March 18.]

Opportunity Sol 760 (Spirit Sol 780)

2011-03-14T06:47:00.000-07:00

It's a memorable day for me because it's my first day back on Opportunity since she hurt her arm back around Thanksgiving. SOWG chair Wendy Calvin sees another reason to celebrate. "Today's a banner day," she says. "Because today we start our two-kilometer-plus trek to Victoria Crater. Larry has suggested a namespace for us to use for a while -- cattle trails, and famous cowboys and cowgirls." Only the good kind, she hastens to add -- not Jesse James.

With uncharacteristically impeccable timing, I've missed all the boring stuff. The agonizing IDD troubles, the slog past Payson Crater -- all in the past. Yesterday they climbed out of Payson, and today we drive.

We'd like to jump straight to a gallop, but Cooper points out that this is our first longish drive with a post-drive unstow. So we play it conservatively, holding ourselves to a 30m drive (even though this means giving back drive time, which kills me).

But while everyone upstairs is happy to be on the trail, there's very bad news from our other faithful steed. She threw a shoe. That is, Spirit made it through the drive just fine, but at the end, during the turn for comm, the right front drive actuator saw a weird current spike. The current draw went from a nominal 0.6 amps way up to 1.5 amps, then, bizarrely, fell into negative territory -- as if it were feeding power back into the system -- went back to positive territory, and flatlined. Then she declared a motion error and stopped turning. So we have a broken vehicle, but since we didn't get our turn for comm, our available data is limited.

I get a chance to quiz Jeff Biesiadecki about this, and he's more than usually doleful. The odds are that Spirit finally blew out her right front drive motor. It's not likely to be a potato caught in the wheel (though we can't be sure, since the poor downlink kept us from getting our front HAZCAM images), since that should have caused the current to spike to 2 amps and stay there until it stalled. Worse yet, with winter creeping up, we can't sit here for a week and diagnose the problem.

We won't know much more until tomorrow, when more data comes down. But the likely scenario is that Spirit has just gone from being essentially healthy but power-starved, to damaged and power-starved -- and damaged in a way that may keep us from getting to the relatively power-rich area we need to get to.

Well, it could be worse. If she were a horse, we'd have to shoot her.

[Next post: sol 762 (Opportunity sol 782), March 16.]

Spirit Sol 779

2011-03-13T06:08:00.000-07:00

The long-baseline stereo drive went reasonably well, though we still ended up with about two degrees of southerly tilt somehow. For that and other reasons, we're ready and eager to move on.

This one's an easy drive, a straight shot down a channel toward McCool Hill. The channel opens up into a broad plain that shortly starts rising toward the hill, pointing our solar panels more and more northerly as it goes. Where we want to be is still about 150m away or so, but today we'll chew off a 35m chunk of that, and we might get where we need to be in a couple of weeks or so.

That won't come any too soon. It seems like the height of Martian summer wasn't that long ago -- Spirit was practically a brand-new vehicle, with 850 or 900 Watt-hours per sol. Luxury. We're now around 350 and dropping. For reference, we need 250 or so merely to survive.

Just as when we were approaching Husband Hill, we're in a race against the sun. One false step, and we're dead. Welcome, as they say, to Mars.

Spirit Sol 776

2011-03-10T04:09:00.000-08:00

Eager Ashley has already planned out a cromulent 30m-plus-autonav drive for us. We never execute it, because it turns out we somehow all forgot to do the long-baseline stereo observations of McCool Hill, and the farther we are from the hill, the better that's going to work. We're all eager to move on -- it's not just Ashley, it's the whole engineering team, and (as it turns out) the science team too. They just discovered that there are these huge sort of rings of layers passing through McCool, of which Oberth and the other promontories are just the most obvious components.

But our exploration of the hills, once we get there, will go much better if we sacrifice a sol now to take the long-baseline observations first. So we have a long pre-SOWG discussion which basically ends up deciding to do the long-baseline drive. Instead of 30m, mostly toward McCool, we'll drive just 8m or so, all visodom.

It's a tedious discussion at times, but Alicia Vaughan (née Fallacaro) is upbeat. "Visitors are good," she remarks as we're standing at the elevator. "They remind you how cool this is!"

Scott Lever agrees. "I've been on lots of projects, and this one is the most fun. Voyager spent two or three years getting someplace and then you'd have two or three days of excitement; this is new stuff all the time. Plus, the team is fantastic -- heck, most of JPL is fantastic. Can you imagine being in the real world? You could be surrounded by idiots."

Ashley's RP-2, but she's on the cusp of starting as an RP-1; she just needs a little more experience. So I decide to be Mister Nice Guy and let her play RP-1 today. It turns out I haven't learned much about sitting back and letting the other person drive; I'm a control freak through and through. I just can't stand seeing it done wrong, you know? By which I mean, of course, not my way.

Well, something else for me to work on.

I get my turn to drive, though, when SOWG chair Albert Yen asks a power-related question at the CAM. "What's our final northerly tilt going to be?"

We hadn't looked at this particularly, because the solar energy maps showed that the whole region was pretty favorable. But to answer his question, I bring up RSVP, check the simulation, and -- oops. It says we're going to have about 5 degrees of southerly tilt, which is pretty bad.

We call a halt to the proceedings while we figure out what we need to change. Careful analysis shows that the magnitude of the predicted southerly tilt is likely bogus; the simulated rover is "settling" on some terrain that's obscured by a rock and is likely much flatter than the software thinks. Nevertheless, there really are a couple of rocks in that vicinity that could end up under the right side of the rover, giving us a southerly tilt. As it turns out, we've got some play in the distance we need to go for the stereo observations to work, and if we cut it by half a meter -- from 8 to 7.5 -- we'll nestle the right side of the vehicle smack between the two rocks, with 10 or 20cm to spare on either side.

With that problem under control, I wander across the hall to chat with Justin Maki before I leave. The other day, when we made it to the edge of Home Plate, we took a NCAM mosaic. The result looked sweet, running from the deck all the way up to McCool Hill -- but not quite to the summit. It was like an otherwise brilliant vacation photo that cuts off the top of your head. So before leaving Home Plate, we took a couple of extra NCAM images of the hill's summit, to fill in the picture. (As it happens, I was the one to argue for it at the SOWG meeting -- Justin's convinced they'd never have listened if he asked for it, but they did it even though I stressed that we didn't need it for drive purposes.) It's amazing what a difference it makes to have it -- the result is just terrific, well worth the two minutes and half-megabit or so it cost us.

"I bet this one will go up on the Web site," he muses. "The last time we did this, that image went up on the Web site. I think I figured something like two million people saw it. So if you look at it in terms of bits per visitor, it's a heck of a lot cheaper than most of the things we do."

[Next post: sol 779, March 13.]

Spirit Sol 774

2011-03-08T02:50:00.000-08:00

That could not have gone better, it really couldn't. I was momentarily alarmed by the apparently large rock we'd driven over, but I was overestimating its size badly -- it was merely 12cm, not 20cm, and thus not a hazard. And as for where we ended up, well ... in front of us is a broad, relatively shallow ramp, only about 10 degrees in slope. To our left and right are impassable steps, but we're going to be able to just turn slightly from our comm heading and glide straight off of Home Plate. Then we can turn and cruise along Mitcheltree ridge until it peters out, and set ourselves up for heading on toward McCool Hill in the next plan (another two sols from now, thanks to MRO).

This could have been much worse. Any number of ways, we could have lost several sols, the sun drifting farther away all the time. Mars just gave us this one, I have to say. And we're only too happy to take it.

Ashley's already been taking a look at the downlink, and since she's shadowing me today anyhow, I have her go ahead and work out the drive. That goes fine (although she puts in a slip check that I think is completely superfluous, grumble grumble).

All in all, it's a relatively easy day. This leaves us time for plenty of demos for visitors, one of whom is Julie Townsend's mother, Nancy, who's out here from Michigan. ("So you must be kind of impressed with Julie," I say to her mom, exercising my talent for ironic understatement. You can lose a thing like that if you don't use it, you know.) She and her friend Annette seem to be suitably impressed, but I get a different picture after they move on.

"It's funny you said that about 'being kind of impressed' with Julie," Ashley whispers to me. "Julie's told me a lot about her parents, her mom in particular, always discouraging her when she was a kid. She'd say she wanted to grow up and be in the space program, and her mom would go, 'Oh, you could never do that.'"

My relationship with Julie has always felt a little strained and awkward -- I like her plenty, I just never felt we got along all that well. Now I have a completely different view of it, and of her. No wonder she seems to feel that she has a lot to prove. Maybe more people should let her know she's proved it. I think I'll try to be nicer to her.

Our other guests are friends of Alicia Vaughan's family. She asked me specifically to give them the MER demo. ("Because you're so good at it," she says. I should start charging, I tell her.) The guests are a married couple. The guy's a friend of Greg's (Alicia's husband's) father -- his ex-business partner, I think -- and his wife married Alicia and Greg. So they're important to her. They're bright and funny, the kind of people Alicia fits right in with. OK, for them, no charge.

I still have the drive up on my workstation when Jim Erickson comes in to check up on everything. Like everyone else, he's nervous about our power situation -- we're down to 366 W-hr, about a third of our peak. As he leaves, he says to me, sotto voce: "Get us the hell out of here!"

I'm trying, Jim. And, lucky for us, Mars seems to be helping.

[Next post: sol 776, March 10.]

Spirit Sol 771

2011-03-05T00:52:00.000-08:00

I wouldn't have had to get up so early if it weren't for the flamenco dancer. Yesterday, everybody was thinking today was going to be tight -- that we needed to get done in time for our uplink at about 18:00 -- and so we needed to start at the ungodly hour of 07:30. It fell to me to point out that yesterday was a two-sol plan. So we need to be done by about 18:00 tomorrow. In other words, we have plenty of time. We could start at noon.

I think I could have convinced Saina, but at a crucial moment, Ashley plugged for an early start. Turns out she had tickets to a flamenco demonstration and wanted to leave early.

Et tu, brute?

Since I have these physical therapy exercises to do in the morning[1], I have to get up at 05:30 to get here by 07:30. So my brain's not firing on all cylinders. Good thing it's an easy day. We spent four hours last night working ahead on the drive and IDD work, which helped. The IDD work gets cut down to nothing but a tool change and a pre-drive stow, so we didn't need to spend the time on it after all, but it was good practice for Terry.

And the time-consuming part of this particular drive was the analysis, which we did last night. We ended up favoring a straight path across the top of Home Plate, cutting off a corner that will save us a drive sol or two without skipping much section. (The corner we're cutting is more or less level with the surrounding terrain, so it exposes little if any stratigraphy.) We can do the whole thing blind; it takes about an hour to do the whole sequence.

Everybody's impressed by the roughly 30m drive, which makes me think just one thing: our standards have fallen most alarmingly. Time was, we routinely did twice or thrice that distance, and thought nothing of it. I'm going to bring those days back, by sheer willpower if I have to. You just watch me.

[Next post: sol 774, March 8.]

[1] Recovering from shoulder surgery.

Spirit Sol 769

2011-03-02T23:33:00.000-08:00

Next week, Spirit goes back into restricted sols. This time it's not because of the Earth-Mars time difference, it's because MRO has its MOI (Mars Orbit Insertion), and their radio's on the same frequency as ours. But whatever the reason, we've got to do a couple of multi-sol plans in a row in order to get ahead of the game. Today we're doing a two-sol plan, tomorrow a three-sol.

Yestersol's drive put us right where we were supposed to be, though as usual there's a twist. The slabs we were told were the most important science targets are out, and the rock we were told to get in the work volume if we could is in. We don't have a whole lot of IDD coverage on it, but we have enough. So the idea is to do IDD work in today's plan and do IDD + driving in tomorrow's. But some of the science team wants to push off the driving even later, not getting back on the road until next week. I think this is a terrible idea, and I show up at the pre-plan to state my opinion.

Saina goes first, running through a presentation in which she demonstrates that we're not actually ahead of our drive metric, but slightly behind. ("Are we ahead of our drive metric?" the first slide asks proleptically. Under it, in huge red capital letters, she answers her own question: "NO!") As bluntly as she can, she points out that our power situation is bad, it's getting worse, and we either move, now, or die. Then it's my turn.

"Saina's an optimist," I begin. "We don't know what's ahead of us, but from what we can see, the terrain gets worse. What's more, past performance is no guarantee of future results; we've made good progress on the stuff we've been over, but there's no reason to think that's going to continue. When we've got clear terrain between us and McCool Hill and we're ahead of schedule -- that's the time to stop and do science. This is not that time."

I turn to the other rover drivers sitting behind me. "Anything you guys want to add to that?" John (who had yelled out "Amen" at one point), Ashley, Antonio, and Terry just grin and shake their heads. "I think that about covers it," John says.

[Next post: sol 771, March 5.]

Spirit Sol 768

2011-03-01T22:53:00.000-08:00

We seem to be doing too well. Having gotten a little ahead of our drive metric in the last couple of days, the science team decides it's time to stop and take a breather. A little IDD work's just the thing, apparently. Never mind that winter's coming on, and if we don't get our shiny metal ass to McCool Hill we'll die. We're just going to divert for a few days ....

The amusing bit is, we're going back up onto Home Plate. Not in the same place we went up before, of course; that's tens of meters behind us now. But they've spotted some interesting rocks up there, and, well, here we go. Back up onto Home Plate.

At least we talk them into a closer rock than the first one they wanted. The first one would have been two drive sols -- one to get close, then another for a fine approach -- before we could even start IDDing. The second one might work out that way, but at least we have a shot at getting there in one sol so that we can start the IDD work tomorrow. This helps because it means we'll be able to drive away over the weekend, which will cut this diversion a little shorter, anyway.

The logic of this decision implies that we'll need visodom, though: we've got to drive about 12m to this thing. We're driving forward past some unclimbable rocks, then arcing up a short but steepish slope, and actually driving past the rock, turning, and scooting backward until it's in front of us. (This sounds strange but avoids large turns, which minimizes the number of time-consuming visodom updates we'll need.) And the oncoming winter is squeezing our drive time. When we put it all together, we realize we're going to need more time than we thought, a bunch more. Saina and Al graciously add in the time, but it means we'll nap less today and have less energy tomorrow.

What I hope that doesn't mean is that it limits our IDD time and forces us to spend another sol here, in which case we'd just end up spending what we were trying to save.

Because we can't afford that. Not with winter coming.

Spirit Sol 766

2011-02-27T21:34:00.000-08:00

"The scientists," Nicole tells me as we settle in for the SOWG meeting, "are all in a tizzy about not receiving any data."

"A tizzy?" I repeat, rolling it around. "A tizzy, a tizzy ... they're all in a heap." She giggles.

I never find out what provoked the tizzy. We seem to have all of our drive data, at least, and we're going to use it; we're starting our partial circumnavigation of Home Plate. Our egress drive went perfectly, and Friday's meeting resolved that we'd traverse the thing clockwise. (This was rather a surprise: counterclockwise was the strongly preferred direction among the oddsmakers, as that path offered much better science. Unfortunately for the oddsmakers -- and for science -- it also offered much worse solar energy, and recent orbital imagery revealed that a troublesome valley blocked our way. Moreover, there was reason to think that the appealing stratigraphy of the counterclockwise route would be obscured by talus. So clockwise won in a squeaker.)

We'd hoped to hug the rim all the way, but the area nearest Home Plate is relatively smooth. Yeah ... a little too smooth. Visually, it's somewhere between the kind of hard-packed, gravelly stuff our rover eats for breakfast, and the kind of shifty, loose, Arad-like stuff we get hopelessly bogged down in. Expert opinion shrugs, so we decide to exercise the better part of valor. I mean to say, we drive around it. This takes us farther from Home Plate, and thus lengthens the drive, but if it keeps us from getting mired in the mud (pray forgive the poetic license), the detour will be well worth it.

At the end of our blind drive, as we're rounding the corner of Home Plate, we have a choice: up onto a rocky, west-tilted ridge, or across the smooth stuff. I aim Spirit right across the smooth stuff -- with a slip check after just a couple of meters, and periodic checks beyond. If it's good for driving, we'll cruise along nicely on autonav. If not, we won't go far into it before the slip check stops us, so we won't have far to back out.

[Next post: sol 768, March 1.]

Spirit Sol 763

2011-02-24T19:36:00.000-08:00

The IDD sequencing is already done (despite a moment where they were discussing entirely changing it), so we're able to focus entirely on the drive. And since I picked out the waypoints yesterday, this isn't too bad. We're going back down more or less the way we came up, so if we hit our waypoints closely enough -- which visodom will help us do -- we know just about exactly what Spirit will experience on the way. It's a steep climb down, with tilts hovering just over 20 degrees, and only a narrow safe channel. To one side, the terrain slopes away even more sharply; to the other, a jumble of exposed bedrock would perhaps take our tilt over the 25-degree limit. "This is one of those drives where you wish you could be there to see it happen," Squyres marvels.

Fortunately, John and I have gotten darn good at this. We mustn't become overconfident, but our success in nailing long approaches, threading needles, and so on, has given us confidence that this will go pretty well.

For no readily apparent reason, the day ends up taking longer than you'd think it would; we're here something like 11 hours. Saina feels bad about the outcome, but Steve gives her a pep talk.

"Look at what we're doin'!" he says. "Complicated IDD work, then a really cool drive, then PANCAM observations of the Phobos transit. Now, imagine going back to sol 40 and saying you're gonna plan all of those in one day. Really, think about it!"

He's right, as usual. Like the rovers themselves, this team has come a long way. And if we can make it to McCool Hill in time, the best is yet to come.

[Next post: sol 766, February 27.]

Courtesy NASA/JPL-Caltech. A frame from the Phobos transit imaging. Hey, we're not all about the driving! The astronomy is pretty darn amazing, too.

Spirit Sol 762

2011-02-23T18:56:00.000-08:00

Today's work is trivial -- an IDD tool change. I'm glad of that, because it gives us a chance to get ahead on tomorrow's work, which will be decidedly less trivial. Tomorrow we're driving across Home Plate -- or possibly back down, so we can start driving around it -- and that'll be after some relatively complex IDD work. Experience teaches us that that's more than we can comfortably do in one day, so we might as well get as much as possible done now.

The problem is that we don't know where we're driving. Well, our basic options are to go across Home Plate, or to go down so that we can go around it one way or the other. So in the couple of hours we have before the end-of-sol meeting, I sketch out the waypoints for each path.

Meanwhile, other members of the team are pointing out that we won't do much driving for the next few days. Monday was a holiday, and we're still in restricted sols, so we can drive on either Thursday or Friday but not both. Or, of course, we could delay the drive until the weekend -- the point is that between Thursday and Sunday, we can do only one drive. We'll have an IDD sol, a drive sol, and two sols of remote sensing and/or recharging. Since the latter are, from a planning perspective, basically free, and we don't have a pass Monday, Saina proposes we do something we've never done before: a four-sol plan, where we come in tomorrow (Thursday) to plan Friday through Sunday all in one day. (This seems like a lot to me, but when she slyly adduces that some people think it's impossible to do a four-sol plan, I'm suddenly enthusiastic. It's like the four-minute mile of rover planning.) If we succeed, that would also mean we'd have Friday off: we'd plan all four sols tomorrow -- Thursday. If we fail, we could just drop the last sol out of the plan and come in Friday to do that one.

Squyres tells her he's for it, too: "Home Plate is the most interesting and exciting science target Spirit's seen so far. I don't want to end up simplifying or cutting science in order to do this. As long as you and I agree we fall back by cutting sols and not science, I'm up for that. It's a deal! Sounds like fun! Let's do it!"

The end-of-sol meeting is an uncommonly interesting one. The topic is where to go from Home Plate, and how to get there. Squyres leads off with a presentation showing Emily and Jake's analysis of our driving situation. We were supposed to leave Home Plate by sol 760 and spend roughly 25 sols driving to our winter home. Curiously, if we delay our exit until sol 780, we get more drive sols in the 25 sols following (thanks to restricted sols and interference from MRO in the earlier period), though the 780 start leaves no time or power for science. "If we leave at 780, there's no stopping even for dinosaur bones," is how he puts it.

There are three big contenders for our winter home:

A flatiron slope to the southwest. This would offer good northern exposure, but the path to it may be blocked, it's far away, and it doesn't look too scientifically interesting.
Von Braun Hill, just south of Home Plate. Its base is readily accessible, but the interesting stuff, a huge caprock, is likely out of reach because the slopes leading to it are too steep. What's left is insufficiently scientifically interesting for a 200-sol winter.
The north flank of McCool Hill, our original plan. This turns out to have at least three huge bedrock exposures (named Korolev, Oberth, and Faget, all after rocketry pioneers). It's farther away than Von Braun, but offers us good tilts and great science.

So McCool Hill wins. But the next question is how to get there -- across Home Plate, down and clockwise, or down and counterclockwise. That's one for me, and I tell them how I see it.

"Any of our three paths to McCool could be blocked. We could drive all the way across Home Plate, only to find there's no way down the other side. From orbital and Husband Hill imagery, we can't prove that we can get around Home Plate, either to the clockwise or counterclockwise directions, without running into a cul-de-sac and needing to come back. Therefore, despite your sol-780 scheme, we need margin: we need to get moving now, and keep moving.

"Of the three paths, I favor crossing Home Plate. Any of the paths could be blocked later, but backing down off of Home Plate will take a sol, maybe two, where we don't make any real progress toward our goal. My next choice would be the clockwise path, since that's better for energy reasons -- we'll have a more easterly tilt. Counterclockwise is my last choice."

Guess which way the science team wants to go? No prize for the right answer. The counterclockwise path will offer significantly better geology. The west side of Home Plate -- the side the counterclockwise path will take us along -- is apparently a much taller face, with more stratigraphy exposed. So Steve punts, asking if we can consider the question Friday, after we've had a chance to do more analysis of the power differences between the clockwise and counterclockwise paths. (The top of Home Plate doesn't appear to offer us anything of comparable interest to either of those paths, so it's out of the running in his mind. Naturally, I've already picked out the waypoints for our first drive along the top. Sigh.)

Well, this gives us enough direction to get ahead on tomorrow's sequencing. We know we're going downhill, so I go ahead and pick out the waypoints for that drive. Plus, they sketch out the IDD work they'll be asking for tomorrow, and Ashley gets that sequence in the bag. Our Monday pass comes back on the table after all, so they drop the four-sol plan -- tomorrow we'll do a three-sol plan, planning Thursday through Sunday and coming in Monday as normal. But we'd have been ready for it. It would have been awesome.

Spirit Sol 757

2011-02-18T15:39:00.000-08:00

So we're up on Home Plate. It could hardly have gone better. Autonav refused to drive the final 1.5m, but it wouldn't have made any real difference; we're perched right on the rim, with a splendid view of the interior of Home Plate.

Including, not too surprisingly, some terrific rocks. There's a bunch of stratigraphic layered material, light-toned rocks (don't get me started), a layered rock immediately behind us in the RHAZ. There's even what looks like a "lava bomb," a rock that starts off as a glob of lava spit out by a volcano; it freezes back into a roughly spherical or football-shaped rock in the air, before it can even hit -- like the way they used to cast lead shot.

The scientists are doing their kids-in-a-candy-store act. I never get tired of it. But Justin decides he's going to put a bit of a damper on things.

"Are we still leaving by sol 760?" he asks pointedly.

Oded's answer is equivocal, something to the effect that he hasn't heard anything different from Steve yet, but without completely rejecting the possibility of staying longer.

He moves on, resuming talking excitedly with the other scientists about which rocks we should choose, but a few minutes later, Justin interrupts again. "Hey, Home Plate's a big place," Justin says. "Why don't we drive across it and see what we see there?"

This is something I love about Justin. As much as I dig the science team, there's a part of me that knows we need to get on the damn road, for the rover's health and safety. Justin manages to express that part of myself, better than I could -- and since he's doing it, I don't have to, which makes it even better.

I don't think his message really gets across (maybe I should have spoken up after all), but they do manage to focus long enough to pick a destination. They picked the big broad shelf of layered material. It'll be an easy drive, looping in a big arc, then turning and zooming straight to our final position. Once again, we're doing an approach of over 10m. We've been doing a lot of these lately, and nailing them one after another, on a vehicle that wasn't designed for more than a 2m approach.

I love this rover.

And that's a reason the subject Saina brings up later in the day is one of my least favorites, a memento mori. But she raises it in a humorous way. For some reason, they're talking about the last piece of free ice cream, which has languished in one of the freezers all this time. You can see the idea hit her, her eyes widening. "I think when the rovers die, we should have a ceremony where we bury the last piece of the free ice cream!" she exclaims. "Or maybe, we all take a bite, and then we bury the stick or whatever."

Time and chance happeneth to all rovers. When they go, I think that will be a good way to say goodbye.

Many years from now, of course. When I'm an old, old man.

[Next post: sol 762, February 23.]

Courtesy NASA/JPL-Caltech. A rear HAZCAM view looking up over the top of Home Plate.

Spirit Sol 755

2011-02-16T14:20:00.000-08:00

The plan for today is to back away from Posey and drive up onto the rim of Home Plate. If everything breaks our way, we'll be able to see over it tomorrow, and we can decide whether to drive across the thing or around it. I'd been hoping all the way to Home Plate that it would turn out to look like a salt flat, and we could just zoom across it -- an easy 100m day. But we've had a couple of glimpses over the rim already, and it looks like it's pretty gnarly up there. So going around might be better.

Terry and I separately roughed out a drive path, basically following a route that John spotted when we first drove up here. And since Ashley hasn't been getting much practice as RP-1, I offer her the big chair.

I have a small regret about this decision. On the schedule, Antonio's supposed to be shadowing today, and he gets less coaching and instruction this way. Well, I'll try to remember to give him some extra opportunities next time I work with him. He turns out to be very useful as an analyst, though; we find a couple of rocks whose size we can't evaluate from our current position, and he goes through more than ten sols of prior imagery until he finds a view from which we can prove they're safe. That probably saved us an hour of work right there, and might have even salvaged the drive itself.

Ashley, for her part, does well with the sequencing. We underestimate how long it's going to take, though, and we aren't really ready at the walkthrough. We catch a lot of errors -- so many that we basically have to go back and walk through it again. But I feel pretty good about the end result.

The drive uses visodom virtually all the way to the top. Visodom is especially necessary for the first leg, where we need to get onto a very narrow path leading to the rim. To our left, the terrain slopes away much more steeply; to our right is a rugged outcrop. But in between is a straight, relatively smooth path that was practically made for our rover, it seems. The tilt gets pretty bad up there, though, maybe bad enough to stop us early. We'll see when we get the data.

For the very last meter and a half, part of our view is blocked by an 11cm rock -- not big enough to be scared of, but big enough to obscure the terrain behind it from our current vantage point. So for that part, we turn on autonav, and turn off allowing autonav to drive backward -- something we haven't done for a long time on this vehicle, if ever -- because we don't want it going back down the slope.

The drive distance is relatively short, but the sequence itself is a pretty complex one -- just one of those that need painstaking attention to detail, all the way through. I hope we didn't miss anything, but I don't have a bad feeling about it.

Maybe I should have a bad feeling about that. But I don't.

[Next post: sol 757, February 18.]

Spirit Sol 753

2011-02-14T13:01:00.000-08:00

"Why are we at this rock?" Brenda Franklin asks as the SOWG is about to start. "It's not that interesting."

Ashley, who was here for all the craziness of the drive to it, just laughs. "It had better be interesting, after all that!" she says.

The drive went damn near perfectly, I'm happy (not to mention somewhat astonished) to say. In a perfect world, we'd maybe have been a few cm closer and a few cm farther to the left, but compared to how things might have gone, I'm definitely not complaining. Everything we wanted to reach is reachable, there's no rock under the wheel -- Paolo's judgment about nudging us to the right was spot on -- and, as a bonus, we're at a slightly lower tilt than we expected. We can RAT to our hearts' content.

And that's what we're doing, along with other IDD work. As we're in restricted sols, we're planning two sols of IDD work today. The first and more complex sol, with an MI mosaic, RAT placement, and other stuff, is the first one; Chris takes that. Terry's shadowing me today, and I sit with him and coach him through building the less complex IDD sequence for the second sol.

This rock -- which, by the way, has been renamed from "Rock A" to "Posey" -- is probably the last rock we'll investigate in detail here at Home Plate, or anyway at this part of Home Plate. After this, we're going to try to climb up onto the rim, take a peek over it, and then decide if we want to cross it on the way to McCool Hill.

Indeed, there's even some discussion about bagging McCool Hill and just wintering at Home Plate. I hear Larry Soderblom discussing this on the telecon as I work with Terry. "It's maybe not the best use of the rovers," he says. "But we could spend some time crawling along the east side" -- which would help aim the solar panels at the sun -- "and there are good geology questions here, ones that our payload is well suited to answer."

They want to bring Squyres into the discussion, but he's on a plane, or is about to be. So I won't hear the end of that discussion. But I'll find out, I suppose, over the next few weeks.

[Next post: sol 755, February 16.]

Courtesy NASA/JPL-Caltech. Astonishingly, we made it.

Spirit Sol 750

2011-02-11T11:02:00.000-08:00

Today was brutal. There's just no other way to put it. Brutal.

The science team has identified four rocks in the vicinity that they'd like us to drive to -- A, B, C, and D. Rocks C and D are definitely out; they'll take multiple sols to get to, and one constraint on the solution is that we strongly prefer something we can get to in one sol. Rocks A and B are about equally easy (or difficult) to get to, but A has a patch of sandy material around it, which B doesn't. So at yesterday's pre-plan meeting, I tentatively identified Rock B as the best candidate.

Last night, I took a more careful look, and started falling out of love with that idea. Another constraint on our solution is that we want to be able to RAT-brush our chosen rock, so that we can get a clean APXS measurement on it, and the RATtable face of Rock B is aimed somewhat away from the best path to it. To get to that face, we'd have to clamber up onto the rock pile beside it, which would simultaneously raise our tilt and reduce the stability of our footing. So that's bad all around.

I send out email about that, and the science team weighs the options at the SOWG meeting. What it comes down to is that Rock A is more eroded, so that there will be less layering for the MI. While Rock B offers better MI-ability, the uncertainty about being able to RAT it tilts the choice in the other direction. So Rock A it is.

Before we drive there, we've got some IDD work to finish up at our present location. And it looks like it's going to be hairy; the scientists are still dithering about exactly what they want, and that never turns out well. I turn to Paolo, RP-2 today and still in training to be a full rover driver. "Paolo, which one do you want?" I ask him. "The drive or the IDD?"

"I'm more comfortable with the drive," he says.

"Great!" I answer. "You get the IDD!"

"I knew that was going to happen," he laughs.

Today's going to be tough for him, I can see that. But at some point he's going to have to get his trial by fire, and it might as well be today.

So Paolo and Terry (who's shadowing him) work on the IDD sequence while I put the drive together. The drive to Rock A turns out to be not so terribly complex; we're basically just backing downhill past it, turning, and crawling back up a bit to put it right in the IDD work volume. As always, the devil's in the details, but all in all it goes quite well.

That is, until the TUL tells me there's another constraint on the drive. We've got to be at a heading of 120 degrees for comm. This is significantly different from the "natural" heading we'd otherwise end up at, about 80. It requires a completely different approach, and that means I've got to scrap almost all the work I've done -- I had already finished -- and start over.

A false start or two later, and I've got the new approach roughed out. We'll back somewhat farther downhill, curving until we're straight downslope from Rock A, then turn to about 120 degrees and climb back up to it. This is going to suck. It'll take longer, it means we're trying to drive up a steep slope through sandy material (with the attendant risk of getting bogged down and possibly even picking up a potato), and we've got less time to study it now.

We don't even notice until the walkthrough that the new approach leaves us with the left front wheel up on a 16cm rock. And there's just not much we can do about it, either. As Paolo points out, our choice of destination constrains us in X and Y, and our heading is dictated to us by comm. Therefore, the rover's final position and orientation are more or less completely determined by the constraints on the solution, and if there's a rock under the wheel as a result, then there's a rock under the wheel. We're able to shift the rover's position by a few cm, but will it be enough? Doubtful.

All in all, I'm quite frustrated by this outcome. We were trying so hard to find a scientifically desirable rock we could reach in one sol; our sols here are already limited, and Monday we enter restricted sols, which means we'll blow two more sols if this doesn't work. And I don't have any confidence that it will work: I think we'll come in Monday and have to reposition. This just sucks.

Worse yet, switching to Rock B (or C or D) at this point wouldn't help: C and D are more than one sol away no matter what we do, and B still has the same problem of higher tilt plus unsure footing, especially if we know we'll have to come at it with a 120-degree heading. So we wouldn't have options to fall back on even if the team weren't too tired and stressed out to attack them.

With all this going on, it's no wonder we discover -- after delivering -- an error in Paolo's IDD sequence. One part of the sequence is a column of MI stacks marching up the rock face. The rock face curves away from us slightly, and Paolo's sequence doesn't account for that. As a result, we're not quite touching the rock at the top end of the mosaic, and the resulting MI images might be out of focus (though the lower images in the stack will probably be just fine). Maybe I shouldn't bother with this, but I have to do my job. I smile sweetly at our TUL.

"Hey, Colette," I say as casually as I can. "What would you say if I told you there was a problem in the IDD sequences?"

Fatigue's written all over her. "Is it a spacecraft safety issue?" she asks.

No, it's not. And our SOWG chair doesn't feel like bitching about it, either. We don't fix it.

So today just was not a good day. It doesn't help when, during our end-of-day post-mortem, our other TUL, Matt Keuneke, says that they discovered that a heading of 80 degrees actually would have been okay after all. We didn't need to switch to the 120-degree heading, with all the problems that introduced. "I didn't feel like we should tell you, though," he says. "I figured you'd kill me."

I'm too tired to care about it. I think that's a real bad sign.

[Next post: sol 753, February 14.]

Spirit Sol 749

2011-02-10T10:23:00.000-08:00

I'm on Spirit today, and Spirit doesn't start planning until 13:00. But I don't get to sleep in: since I'm also an Opportunity driver, I have to come in early for a meeting about Opportunity's drive strategy and the latest on the stow/unstow business.

It sounds to me as if the Opportunity science team hasn't yet grasped the consequences of our situation, or isn't that gung-ho about getting south to Victoria, or some of each. Squyres wants to "turn the keys over to the rover planners," as he's put it, and let us book to Victoria as fast as possible. I'm sure that at least part of what's behind this is to try to get us to that crater, the so-called geological promised land, while we still have a working IDD.

But the near-term consequence of this choice would be that we'd likely bypass Payson, a juicy chunk of outcrop in a corner of Erebus Crater. And the rest of the Opportunity science team doesn't want to give that up. Instead, they want us to descend into Erebus Crater, wade through tens of meters of sandy stuff to get to a point from which we can image Payson, then struggle on further to a point from which we can exit Erebus, maybe. Unless we can't exit there, and need to go all the way back to where we started. All this we're supposed to do with an IDD that we have to guarantee we can safely unstow at the end of each drive as we plow through that stuff.

But the science team obviously feels strongly about this. Jim Erickson ducks in to say that there's a rebellion brewing -- the science team against Steve. "We need an answer for them," he says. "Give them time to go berserk, argue, and come to a decision."

We've got a story already: go about 80m south, evaluate the path into the crater, and make a decision there. That'll have to do.

With this and other things, I miss the Spirit SOWG meeting for the first time since I don't know when. (As RP-2, I don't really have to be there, but I don't like to miss them anyway.) But thisol's not complicated, just a tool change. I leave it to Paolo and Ashley to put that together; it's simple and only takes a few minutes. When they show it to me, I ask idly, "So we're not hitting the turret limit or anything, right?"

Paolo brings up the plot of the turret angles, and it shows we're going to 3.15. "Ah, shoot," I say. "Our limit is 3.14."

So they have to do it the hard way, tweaking the target's surface normal and redoing the approach. This takes at least half an hour of tedious work, and Paolo's barely able finish it before he has to rush off to do something else. But he gets it done, and it looks great. We're now going only to about 3.09, well away from the 3.14 value.

In the few minutes remaining before the walkthrough, I sit down to check out the details myself, including running our flight rule checker on it. Among other things, the flight rule checker knows the acceptable turret limits -- which, it turns out, I've misremembered. The upper limit is 3.3. We were fine in the first place. I made Paolo and Ashley do all that work for nothing.

I put the sequence back the way it was, walk through it in that state, and deliver. When Paolo returns, I apologize profusely, but he good-naturedly laughs it off. "It was good experience," he points out. There are sols when we really need to do that, and, as he says, he needed the practice.

Still. I am such an idiot.

Courtesy Wikipedia. Erebus Crater, looking from a distance at the Payson outcrop that was so attractive to the science team.

Spirit Sol 746

2011-02-07T08:24:00.000-08:00

We're not starting until 11:00, but I'm in at 09:00, and it turns out John has been here a while already. "Need any help working out the drive?" I ask him.

"Drive's already done," he shrugs.

Which is reasonably close to the truth. All the drive-related data came down yesterday, so we've already got enough to plan, and John's roughed out the approach already. He's got us climbing up the side of Home Plate to a patch of coarse-grained outcrop the scientists are slavering over. When we get up there, our pitch is going to be over 20 degrees. Hillary, all over again.

OK. When we were at Hillary, what did we wish we'd had? Wiggle-cams, for one thing. Higher-precision data at the end of the drive, for another. So we include that stuff in this sequence.

Speaking of drives, the Opportunity drive Frank and I planned Friday crapped out: we backed up a meter, turned, and tripped the hyper-ultra-paranoid suspension limits during the turn. So we're not where we wanted to be. What makes this more painful is that we knew the bogies had hit 5.5deg coming in here, and the limits we've been using were 6deg -- so we knew this might happen, discussed it, and decided not to mess with the limits. Now I kind of wish we had (though Ashitey points out that maybe it's better we didn't: we're supposed to be conservative like this while we get used to this new hover-stow driving).

Having screwed up both Spirit and Opportunity drives in the last week or so, it's hard not to feel like I'm in something of a slump. I hope that tomorrow's data shows I'm out of it.

[Next post: sol 749, February 10.]

Opportunity Sol 723 (Spirit Sol 743)

2011-02-04T06:26:00.000-08:00

Yestersol I came in with Matt Heverly and Frank Hartman to take a look at the RP-0 sequences Jeng and Ashitey had put together for thisol. To our astonishment, they'd decided to send up the previous sol's sequences despite wrist-flip problems -- which can cause the sequence to fault out, if you're even a little unlucky -- and their RP-0 sequences had the same problem. Yestersol's sequences worked fine, but Frank and I are of one mind that thisol's need to be fixed.

However, despite our needing to make some small changes to both the IDD and drive sequences, the draft versions save us a lot of time and stress. More than enough for me to start putting together canned stow, unstow, and rotor-resistance-setting sequences for us to use in our new stow/drive/unstow driving routine. (To my annoyance, we decide not to uplink these sequences on this sol, because we haven't yet figured out how we're going to safely deactivate them if they should run unusually long. But I get them built, anyway.)

Martian winter is setting in. One of our first signs of it is longer heating times required in the drive sequences, after which we tell the spacecraft to expect colder temperatures despite the heating. And, Bill Nelson points out, we're no longer in a relatively warm crater, as we were last winter; we're out on the chillier plains. This is bad news for Opportunity's Mini-TES, which is especially vulnerable to the extra-cold temperatures it experiences when we must Deep Sleep to conserve power. They call Squyres to ask him about this -- should we curtail activities to avoid Deep Sleeping, or accept the additional risk? "Take the risk," is his call. You can hear the shrug. "We made this decision basically one Martian year ago." If we lose the MTES, we lose it -- although that would truly suck on a rover that already has a failing IDD. If the IDD and the MTES both go, we're left with only the PCAM for science instruments.

The power loss has another implication: we'll have to Deep Sleep nightly, meaning we'll have fewer comm passes, meaning we'll get less data daily. (If we won't have any science instruments to return data from, that's not so bad. I didn't just say that.) Frank's been asked to put together a scheme for driving with only 40 Mbits of downlink per sol, which I would have thought unlikely until he shows me the scheme. It'll be tight, but I think we can do it -- and oddly enough, I think this will help focus us on driving. We'll get to a point where we can't afford to do anything else.

Speaking of driving, John Callas stops in to pick my brain about strategies for driving more meters per sol on the way to Victoria, which NASA HQ is now apparently starting to push hard for. I talk about the same stuff with him as I have with Frank -- using autonav, lengthening the distance between slip checks, and so on.

But the big thing, I tell him, is to get the scientists pushing for driving. And the only demonstrated way to do that is with a drive metric: pick a sol, and say we're going to be there by that sol, and keep putting our progress (or lack of it) up on the board every day for all to see. This doesn't work perfectly; the scientists will spend on credit. And sometimes, as with Spirit, there isn't enough margin left, and we don't get to Home Plate on time. Not that I'm bitter. But it works well enough, all the same.

The odd part of this conversation comes when John reveals that he's a bit of a train nut. "Oh, if my dad ever comes out for a visit, I'll have to introduce you," I tell him. "He was an engineer for CSX transportation -- retired just a year or so ago."

John's eyes light up like a little kid's. "When is your dad coming for a visit?" he asks eagerly.

A visit from one project manager just wouldn't be enough. Our sadly-soon-to-be-ex-project manager, Jim Erickson, also pops by. He's already splitting his time, and soon he'll be gone from MER for good. Julie asks him how things are going.

"Okay," he says.

"Just okay?"

He shrugs. "It's much less fun to do two things badly than to do one thing well," he says.

[Next post: sol 746, February 7.]

Spirit Sol 739

2011-01-31T03:48:00.000-08:00

The weekend went flawlessly. The MIs completed without a hitch, and they look absolutely gorgeous. Oded was right about this being a vesicular basalt (though it turns out to be wind-eroded as well, which confuses the issue), so it turns out to have the scientific value they were hoping for. ("You sure got lucky on this one, Oded," one of Friday's objectors graciously admits at the SOWG.) But as I told him in email I sent him over the weekend, if this IDD deployment wasn't worth it for the science, it was worth it for the art. The thing is weirdly twisted, with little fingers sticking up and out every which way, reminding me of one of those Japanese woodcuts with the waves. By the famous Japanese artist, uh, What's-His-Name-San.[1]

It's a bit of a shame we only had time for MBing it, but as it turns out, Oded says, "I'm not sure we would have gotten a good APXS measurement on this thing anyway. It's so eroded, and has soil blown into all the eroded spaces; I'm not sure the instrument would have seen anything."

Too late now, anyway: that rock's 30m behind us, thanks to John's excellent driving. (During which time, the dynamic brakes appear to have been no problem at all. Nice to have that behind us as well.) That's pretty good for recent drives, but it won't be good enough. Our plan was to be at Home Plate by sol 740 so that we could do 20 sols of science and be zooming toward McCool Hill by sol 760. Since tomorrow's sol 739, and our radial distance to Home Plate hasn't changed much -- the weekend's drive was mostly moving laterally to Home Plate, skirting Mitcheltree Ridge -- we have essentially no hope of making it there on schedule.

Moreover, our power situation's bad. The sun keeps heading north, and we're on south-facing slopes. One of the ways this is starting to affect us is in our downlink: we can't afford overnight passes until our power improves, so they have to cut science to the bone. And even then, we can afford only 2.5 hours of driving.

Sigh. Winter. I haven't missed it.

Thisol's blind drive is limited by the ridgeline, still about 20m away. The drive sequence is a fairly simple one: skirting around a couple of nearby rocks (that aren't really big enough to hurt us; we're avoiding them mostly on principle), scoot to the ridgeline, turn on autonav, and hope it will find a path downhill. If it doesn't, we'll probably still be OK: perched up on the ridge like that, we'll have a lovely view of the scene before us and should be able to plan a wicked blind drive on the following sol. Although that honor will have to go to Paolo; I'm off tomorrow, darn it.

After the walkthrough, John decides to change the sequence slightly to give us a little more margin around a sandy hollow. None of us notices that he introduced an error. The first waypoint, instead of being executed blind and taking just a few minutes, will be executed in autonav mode. If it completes at all, it'll take about 45 minutes.

Oops.

We don't notice this at the CAM, and almost everybody leaves. John's building the animation for the uplink report when he notices something funny -- the rover moving much more slowly than it's supposed to through that bit. We end up calling everybody back in to fix it.

I'm glad he caught it, and I'm glad, upon reflection, that it's been so long since we've had to do something like that.

I'm not so glad that we didn't catch it earlier. We come up with a fr_check rule that would catch it, but the underlying problem -- human error -- will be less easy to eliminate.

[Next post: sol 743 (Opportunity sol 723), February 4.]

Courtesy NASA/JPL-Caltech. One of the MI images we took of this rock. Man, this thing is cool. More here.

Footnotes:

[1] Hokusai. This, courtesy of Wikipedia, is his woodcut Great Wave Off Kanagawa:

Spirit Sol 736

2011-01-28T01:49:00.000-08:00

Once again, I woke up in the middle of the night with an urgent desire to check on the drive ... and looked at the clock, decided not to make this a habit, and went back to sleep.

By the time I get in, Ashley and John have already roughed out the next drive. Yestersol's drive made about 26m of progress, stopping when autonav failed to find a path between Scylla and Charybdis (as we thought might happen). Still, this is a decent showing -- I think we might have actually caught up on our drive metric a bit (we're now 90m behind on that, maybe 170m from Home Plate) -- and we're ready for the next one.

And boy, are we ever ready for the next one. We got all the diagnostic data down, and Jeff Biesiadecki's call is that this is merely a recurrence of the previous Spirit steering anomaly. So we're good to ignore the dynamic brakes and resume normal driving. Triumph!

The original plan for the weekend had been to resume the autonav-only continuation-drive sols. But there's this rock smack dab in the middle of the IDD work volume .... It's not a big rock, only about 5cm tall and 12cm wide. But it's possibly a vesicular basalt, a rock type of particular interest to at least some of the science team. In particular, to Oded Aharonson. And since he's the SOWG chair today, there'll be at least one voice calling for a change of plans.

I'd like to be able to argue that we should blow it off and drive. But when Oded asks, I have to admit that the autonav-only sols haven't been performing well. Let's be generous and figure that we might make as much as 40m from a two-hour autonav-only drive. But if the first sol stops because autonav can't find a safe path, the second won't even try to move. Given the increasingly rocky terrain we're in (it looks like we're seeing another ejecta blanket), I figure there's about a 70% chance of no progress at all on the second sol. Which really means we're giving up only about 30% of 40m, or about 12m -- and that's using generous assumptions.

With those numbers in front of him, Oded can't resist the rock. Though the matter is unusually contentious at the SOWG meeting, with a number of the science folks saying we should skip the thing. (Justin is particularly vocal, and characteristically stubborn. At one point I suggest we let him name the rock; that idea gets a big laugh.) We have time only for MB or APXS, not both, and the results from only one of these instruments are a lot less scientifically valuable than the results from both together. Oded, however, makes the point that we mostly want this thing for the MI images -- morphology is the key to a vesicular basalt, more than chemistry -- and he gets his way in the end.

It's a more than usually tough sol. John and Ashley worry about the drive, while Terry and I take care of the IDD sequencing. IDDing this rock is just plain tricky: we want to try to get four MI stacks on it, but its small size makes that awkward. The least dusty and therefore most desirable face is toward us -- not on top -- so as the IDD gets close enough to plant an instrument on the rock, the hardware slides uncomfortably close to the ground. Worse, the rock is more or less rounded on top -- kind of like a half-buried football -- so that as we raise the IDD to increase its clearance from the ground, we get much less rock in the instrument's field of view. If only it were a LEGO brick.

The other tricky part is that the face we're poking at is fairly irregular, so that a simple linear mosaic won't do; we need to customize each stack, and have a MB touch for each (each of which also needs to be carefully analyzed to ensure we won't smack into the ground). Oh, and the MB will contact the rock at its outer surface, but because it's a vesicular basalt, we want to see into the vesicles -- the holes -- so we want to take MI images as close as 11mm. Which means we get that much closer to the rock, and to the ground ....

But, what the heck, we make it. And by aggressively parallelizing the work, we finish the whole thing -- from start of SOWG to end of CAM -- in only about seven hours.

Maybe we could have thrown in that autonav-only drive as well ....

[Next post: sol 739, January 31.]

Courtesy NASA/JPL-Caltech. Stupid vesicular basalt. Grumble, grumble.

Spirit Sol 735

2011-01-27T01:10:00.000-08:00

Things being in the state they're in, we start the day with an oddly subdued anomaly meeting. Yestersol's drive went OK, with occasional warnings about the dynamic brakes, but since we had disallowed steering on those wheels, there were no resulting faults. The drive terminated after 9m (actually 8.99m, bleah) due to the hazard-avoidance code's decision that there was no safe path behind us. This was really the result of a hair-triggered autonav tilt setting; we're actually quite safe to drive on. Indeed, as one person points out, we're far enough behind the drive metric that driving is the conservative option.

And that's the plan: drive. We might not be able to make that much progress, but at least we'll fall behind our drive metric more slowly this way. (We're about 110m behind now, and roughly 170m from Home Plate.) Due partly to some impassioned pleading on my part, we're going to pack pretty much all of the diagnostics into this sol, so that tomorrow we can plan a normal -- and, I hope, long -- drive for the weekend. Maybe even a pair of drives: we're far enough behind the drive metric that every meter counts, so we might revert to the autonav continuation thing.

John Wright's raring to drive, to the point that I actually have to rein in his enthusiasm a bit. He originally sequences it as a 40m all-blind drive, but I'm uncomfortable with that. The drive sequence is mainly made up of little helpers that check our heading, then take a 60cm step. If we're aimed too far to the left, the step veers a little to the right; if too far to the right, it veers a little to the left; and if we're close enough, it just goes straight.

The problem with this is what happens in the marginal case: you're aimed off course, but not so far that you veer back on course. This keeps you inside a cone centered on the desired heading, but then you have to be sure that the cone doesn't include anything scary. I put together a version of John's sequence that shows the worst case -- what happens if we skate along the extreme left edge of the cone -- and display it on the big projection screen. All kinds of bad stuff is in there -- a sand trap, some big rocks, you name it. He takes one look, hems and haws for a minute, and does the right thing. We scale back to a 23m blind + 15m autonav drive, with tighter limits on the helpers.

Coming back from lunch, I bump into Mark Adler in the elevator. "How'd it go with the Congressman?" he asks.

"Oh, I thought it went pretty well. People seemed to think so."

"Good," he says. "I was talking to Gail Robinson about you." He sees my blank look. "She's Elachi's assistant," he explains. "She was there that day when he brought his tour group through. Yeah, I was talking to her about the Congressman's visit, and she asked me, 'Who was that guy we talked to?' I told her you should do it."

That explains a lot, and is actually pretty close to what I figured. "I wondered what happened with that," I say. "I was like, how would Charles Elachi even know who the hell I am?"

"He knows now," Mark says.

Spirit Sol 734

2011-01-26T00:30:00.000-08:00

I woke up at 3AM with a bad feeling about the drive. I logged in from home, checked out the data, and sure enough, something bad happened. This would sound impressive, as if I'm psychic or something, were it not for the dozens of times that I've done exactly the same thing and the rover's been perfectly fine.

But she's not fine this time. Most of the automated post-pass processing isn't done yet, so I have to fumble around in the low-level data for a while. But I work out that Spirit had executed the 40m blind waypoint just fine, but when she turned to set up for her first autonav waypoint, she experienced some kind of motor fault.

Oh, this is bad. This is genuinely and truly bad. The only thing I can remember that's caused something similar to happen is when we picked up a potato while climbing Husband Hill, and the pain and the time it took to recover from that -- it doesn't bear thinking of. And we don't have time for an anomaly recovery now, considering how far behind our drive metric we are.

To get a clue as to exactly what might be wrong, I grep the past data for the warnings I'm seeing here. They turn up twice: once on sol 265, and once on sol 277. I check my notes to find out what was happening on those sols, and I'm almost relieved to find that it wasn't potato time, it was the dynamic brake anomaly. What happened then was that Spirit lost the ability to sense the state of some of the brakes that keep the wheels from wobbling (uncommanded steering) during driving. And since her FSW couldn't get responses from those brakes, she freaked out. Eventually, after exhaustive analysis and testing, we decided that the brakes were working fine -- she just couldn't tell they were fine after commanding them -- and sent commands to ignore their state. And then I just forgot about it, because everything has been working fine since then.

The brakes work in connected pairs: one relay controls the RF and LR brakes, another controls the LF and RR brakes. Last time, the first of those pairs failed. This time, the symptoms are the same except that the motor IDs are different, indicating that the other pair has failed.

If we were going to have a problem like this, this might be the best problem we could have had. We'll have to do some analysis, but the odds are that we'll just do the same thing we did last time: tell Spirit to continue commanding the brakes but ignore their status, and life returns to normal.

Oh, please, oh, please, oh, please.

At least it's not my fault. This doesn't mean I don't get ribbed for it. As Chris Leger walks into the SOWG meeting room, he rolls his eyes at me. "You just had to break the rover, didn't ya?"

"I know," I say mournfully. "You give it to me for one day, and look what I do to it."

(He also points out a 25cm rock that we juuust missed. The tracks skate right by it. We could have gone over it, but it's alarming to have come this close to something that's right at our danger threshold. I look back at yesterday's PCAMs, pick out that rock, and measure it. I feel vindicated when I see the same number I saw yesterday: 19cm. "Yeah, I don't trust those rock heights," Chris says, looking over my shoulder. "I'm starting to see why not," I reply shamefacedly. It's possible the rock isn't actually that big; all we have are the HAZCAMs at this point, and their range data is sketchy. But still. As bad as things are, this is a vivid reminder that they could have been much, much worse.)

Chris is RP-1 today, and Ashley's RP-2. I'm neither -- I'm off shift today -- but I can't bring myself to ignore what's going on, so I decide to stick around for the SOWG meeting and the subsequent, hastily assembled anomaly meeting.

Options on the table at the SOWG meeting are to do mobility diagnostics and remote sensing, or mobility diagnostics followed by a drive. The latter option might sound surprising, but it's not terribly so: if Spirit fails the diagnostics, she'll raise an error and refuse to drive; if she passes, why not let her drive as far as she can get? We are, after all, 100m behind our drive metric, and 200m from Home Plate; we need to make all the progress we can. However, this isn't the place to make that decision.

That comes at the anomaly meeting. It's clear what the problem is, and we've been down this road before. (Or so we think, but one of the assignments coming out of this meeting is to ensure that this really is the same problem as before, as opposed to something else that's manifesting in a similar way.) We won't be able to do all of the diagnostics we'd like today, as we need to do some testing in the testbed first. (Luckily, Chris had the testbed reserved today anyhow.) But, somewhat to my surprise, we get the go-ahead to drive. We need to make sure we won't hit a sandy patch and dig in, but "with the appropriate bells and whistles," as John Callas puts it, we're cleared to drive 20m or so. Anything to get us closer to Home Plate!

Steve Squyres, dialed in on the telecon as usual, asks perhaps the most important question of the meeting. A scarred veteran of the ongoing Opportunity IDD anomaly, he asks, "Are we confident we can keep the program office and NASA headquarters out of our faces on this one?"

Callas cups his hand behind his ear. "Sorry, Steve, you're breaking up," he jokes.

I do my little part by looking into the timeline of events the last time we went through this -- what responses did we have, and in what order? Just as I'm finishing that, I get pulled into helping with the drive sequence.

Did I mention that I'm not on shift? I had other stuff I meant to do, but oh, well, who am I kidding? I love doing this.

Most of the rest of my day is taken up in another meeting, the Opportunity IDD science meeting. Two years and one day, it's been, and we're discussing how to drive with our gradually degrading arm. This meeting is to get the science team's buy-in on what we should do. The slides make the point, in large red letters, that we're time-limited, not usage-limited -- the IDD is going to fail at a certain date in the future whether we use it or not. The four options Ashitey presents are these:

1. When driving, stow the IDD, drive, then unstow again. This avoids leaving the IDD stowed during a thermal cycle (i.e., overnight), and has a narrow but nonzero window of vulnerability where the IDD could cease to work during the stow and be permanently stuck somewhere under the vehicle. This could block the FHAZ's view of the terrain, and worse, as the arm bounced around during drives, the elbow would gradually drop farther and farther until we were dragging the IDD on the ground like an anchor.

2. Drive in the thinker-stow configuration, as we did the last time. This will badly limit mobility -- best case, we could drive over 7cm obstacles, and our poor ability to reliably detect obstacles of that size would limit drives to 5-7m per sol.

3. Combine options 1 and 2: use option 1 for long drives, 2 for short drives.

4. Stow the IDD and never use it again.

"I don't think option 4 will be the favorite of the scientists," Ashitey jokes.

There's hardly any argument; everyone on the science team favors option 3. (As does the engineering team, but it's not our meeting.) Ray Arvidson's response is the most poetic: "Think fifty years into the future and think about our legacy. Our legacy is going to be the major stratigraphic sections we've done -- at Eagle and Endurance, and now this one in front of us. We have to protect mobility, and not at the rate of five meters per sol."

"Even if the IDD fails, we still have a bang-up mission in terms of remote sensing," he adds shortly afterward.

Squyres sums it up: "We all hate option 4, and option 3 combines the best of 1 and 2. As Jim Erickson said in the anniversary celebration the other day, our job now has become to use these rovers up. That doesn't mean we can be cavalier about using these vehicles, but we don't get any points for ending this mission with a healthy vehicle on the surface of Mars."

This is all correct, but depressing. All good things must come to an end, but is it so wrong to want them to live forever? Or at least until I get sick of them?

Not that there's a difference.

Spirit Sol 733

2011-01-24T23:51:00.000-08:00

The thing is, I'm not even supposed to be working today. I originally had a doctor's appointment, which I rescheduled to next week so that I wouldn't miss the big Two-Earth-Years-On-Mars celebration over at von Karman Auditorium. It was supposed to be a big deal; the Lab's making a fuss over it, inviting press and congressmen, and so on. And there's usually free cake at these things. So, you know. Cake.

Then, last week, I got a call from John Callas. "Are you working next Tuesday?" he asked.

"Nope," I told him.

"Okaaay," he said slowly. "Well, you know that Congressman Drier is coming next week for the anniversary celebration? We wanted someone to help him pick out a science target, and Dr. Elachi requested you specifically."

Well, if the Director of the Lab wants me specifically .... Wait a minute, I think as I hang up with John. How would Charles Elachi even know who the heck I am? What I figure is, he's remembering a few weeks back, when he and Pete Theisinger brought some tour group through and I gave them a spiel. He probably said, "That guy did a pretty good job -- whoever he was, use him."

However it happened, I'm now on shift on Spirit. (And I'm getting teased a lot about being famous. Worse, the story has now mutated -- Charles Elachi asked for me by name, according to the new version, which is not how I heard it, anyway. But let's leave all that aside.) The plan for Drier's visit crystallizes into having him choose which of a pair of science targets we're going to take an image of before we drive today. (It was originally to choose between a couple of IDD targets, but we're not IDDing today, so that's out.) Taking these images is, of course, not my job, but as Sharon Laubach says, "What we're going to do is: fake it."

I can do that.

I talk to the science team and get a sense of the two targets we're going to have the guy choose between. The first is a patch of light soil -- indicating maybe salts, which of course are mobilized by water, which is what we're all about. The other choice is a pair of nearby rocks, which Larry Crumpler thinks might represent the leading edge of an ancient lava flow; studying them might give us clues about the properties of the lava and of the paleoclimate on Mars at that time.

The sequencing itself is pretty straightforward -- a relatively simple drive. And that's a good thing, because one way or another, the Congressman's impending visit keeps interrupting.

First, Jim Erickson comes in, followed quickly by John Callas, Pete Theisinger, and Fouk Li. They ask me to go over what I plan to show Drier.

"Well, I'm gonna do the whole spiel about where we are, how we work, and so forth. Then I'm gonna show him the first picture, with the salts, and then the second picture, with the two rocks, and then invite our guest to choose which one we should take the picture of."

Jim cocks an eyebrow at me, playing the Congressman's part. "So you're saying, no matter which one I choose, the scientists will be unhappy?"

"I'm saying, either way, the scientists will be equally happy," I reply smoothly. "They're both excellent choices."

That seems to work. They flutter a bit more, make a couple of good suggestions, and then disappear again.

I get back to work, and the next thing I know, it's coming up on time for the anniversary celebration and Congressman Drier's still not here. I'm not fretting; I've got plenty to do. Besides, he's one of the main celebrants -- a star of the show. They'll wait for him.

But they are trying to keep from getting too far behind, as I discover when Callas pops in. "Uh, we're running kind of late," he says. "Try to keep it to about thirty seconds." He pops out again.

I can't help but laugh about this. Whatever they want, I figure.

At last, Congressman Drier and his entourage show up. One guy's from the LA Times, another's taking pictures (I assume for the press, though I don't know). One is Sally Ride.

I do the usual speech, explaining what they're looking at, how the commanding process works, and so on -- trying to keep it short, although of course I have no hope of keeping it down to thirty seconds. Still, they don't seem terribly anxious to leave, which I take to be a good sign.

I get to the point about choosing between the two images, and I start this way. "Just as in Congress, you can't spend every dollar you want, so it is that we can't take every picture we want."

"Ah, we just spend all of 'em!" Congressman Drier says.

"Uh, you do remember that the LA Times is here, right?" I tease him.

He doesn't want to choose either picture, showing his political instincts, so we agree to flip a coin. The rocks win. I talk to them a little more about where we'll go from here, answering questions from the congressman and his group, and they move on.

As they're leaving, I take my chance to say, "The Sally Ride?"

She grins. "The Sally Ride," she confirms.

I don't meet a lot of people with cooler jobs than mine, but the first American woman in space is on the short list. "I remember watching your shuttle go up," I tell her. "That was awesome."

She grins again. "It was cool for me, too," she says.

Overall, I thought the visit went quite well, and I'm not the only one. As soon as our guests are out of earshot, people start congratulating me. Including Squyres, who I didn't realize was listening in on the telecon: "Good job, man," he says. "That was really well done!" Coming from someone like Steve Squyres, that's high praise indeed.

So then we all troop down to von Karman for the festivities and cake. They turn out to be filming a TV show, with multiple cameras, including one on a boom that gets those swooping shots of the audience. We are of course late -- although the Congressman and his crew are still not there, and don't show up for another 20 minutes or so -- so I end up standing at the back, with Mark and Ashitey and Ashley and Craig Leff. Waiting is not so bad, though; on the big video screens at the front, they're flashing congratulatory messages emailed from people around the world. One says that she gets so lost in looking at the images sometimes that she automatically starts planning hikes in them. "I have to remind myself that these images are on Mars!"

"I and my ten-year-old son have been following the progress of the two rovers every day since they landed," writes another woman. "Thank you."

When the thing gets started at last, it's pretty much what I would have expected, with Elachi and others saying that it's not the machines, it's the people, and so on. And the mayor of La Canada Flintridge presents us with a proclamation from the city, as well as taking a few good-natured jabs at the mayor of Pasadena (who sent a similar proclamation in absentia). In between, they show video segments that I suppose will form the main part of whatever this TV show ends up being. I'm even in some of them -- in the foreground, yet; they used some of the video footage they shot when they were putting together B-roll for the CBS Evening News. Every time I show up on the screen, the people around me rib me about it. It's cool, though.

One of the speakers is none other than Steve Squyres, who couldn't be here in person, so they put up a picture of him and pipe in his voice via phone. "Most of the team's so used to me being just a voice on the phone that this is really the most fitting way to do it anyhow," he jokes.

His little spiel is about teamwork. "What's really made these rovers succeed is teamwork. In fact, I was just listening in as one of our rover drivers, Scott Maxwell, was talking about a couple of science targets to Congressman Drier. Now, he's an engineer. But his explanation of the science was as good as I could have imagined. And that's the kind of teamwork I'm talking about, between the scientists and engineers."

Aw, shucks.[1]

Today has got to rank among the best days of my life. It's so great, I don't even care that in the end, there's no cake.

Footnotes:

[1] I might as well admit it. I was ... there's a Yiddish word for this, kvelling. It's when you're so happy there's a light in your tummy and it's shining out of you no matter what you do about it. I was kvelling.

Opportunity Sol 712 (Spirit Sol 732)

2011-01-23T23:11:00.000-08:00

"I think I owe you a beer," says Larry.

"You got lucky," I tell him, "I don't drink."

He's referring to the fact that our drive wasn't quite perfect. While we ended up almost exactly where we wanted to go -- and we still have an IDD -- Upper Overgaard was just slightly out of the IDD work volume. However, the next-priority targets, located on Lower Overgaard, were reachable, and Opportunity did some IDD work on them last week.

And she was supposed to do more over the weekend, but she spazzed out again. Just at the end of the first IDD mosaic, when she was all of one milliradian away from returning to the ready position, she experienced another joint stall. To make matters worse, it was a joint-2 stall -- not a joint-1 stall, as we have been seeing -- and nobody seemed entirely sure what to make of that.

So they did some diagnostics over the weekend, and the good news is that Opportunity passed those with flying colors. The general feeling is that there's nothing to panic about and we should just proceed with IDD work today. We obviously want some diagnostic info, but in this case there aren't any diagnostics that would be materially better than just continuing the IDD work, and obviously we get science as a bonus with that.

That is, that's the general feeling among the engineers in the meeting we're having about it. And it's echoed by the scientists. As Matt Golombek puts it, "Upper and Lower Overgaard are one of the highest-priority science targets we've had for 200 sols. Even if we knew we had only five uses of the IDD left, this would be one of 'em."

So with science and engineering in complete harmony, we should be all good to go. But as usual, things are more complicated than they have any right to be. For one thing, it's not immediately clear that we're going to be doing any planning on the rover today. Because of the unusually high winds and accompanying wind-blown debris here at JPL, people are now being turned away at the gate. That apparently has included data management people, and Opportunity's tight on flash, so without them, we might not be able to do anything useful thisol.

That problem gets solved when Jake tracks down a data management guy who arrived early -- he's not technically on shift but agrees to help out. But there are other problems as well. Chief among these is that we need approval from NASA HQ before we can proceed, and we haven't gotten it yet. They spend some time rehearsing their arguments, to maximize the chances that HQ will accede. Joe Melko makes the point that what's killing the IDD is simple thermal cycling, not usage. Whether we use the IDD or just sit here and fret, its lifetime's the same. "You shouldn't be afraid of using it, you should use it as much as you can while you still have it."

"Use it or lose it," Squyres paraphrases.

"No," I point out. "Just 'lose it.' Whether you use it or not."

On the assumption that HQ will show good sense, we go ahead and plan for the resumption of the IDD campaign. The sequence has already been built, although it wrongly used 26mm (not 23mm) for the MI best-focus position after the MB touch that precedes each stack; that's something I'll have to change, but it's trivial to do. However, before I can really sink my teeth into it, Squyres is on the telecon.

"No IDD," he says flatly.

Everyone groans. We've just finished the APAM, and we now need to replan everything, as well as losing another sol to this problem for no good reason.

He seems to feel he owes us an explanation. "Basically what happened over the weekend was, people at JPL who didn't know what was going on made promises to people at NASA HQ who didn't know what was going on, and promised we wouldn't use the IDD at all until HQ was brought up to speed." And for some reason, the woman at HQ we need to speak to is unavailable today.

"This is ridiculous!" Matt Golombek fumes. And he's not the only one.

"Hey, feel free to vent, guys," Steve says. "Callas and I just yelled at each other -- I yelled at him and then I felt better, and then he yelled at me and then he felt better. But at this point, promises have been made that can't be unmade."

We can all see the justice of this, as frustrating as it might be. I (and others) thank Steve and John for trying anyway. And then they replan the rover's day, and, I'm sorry to say, it won't include me.

Opportunity Sol 707 (Spirit Sol 728)

2011-01-19T20:33:00.000-08:00

Ah, that's a relief! Our second try at stowing the IDD in the "thinker" pose worked! The images look just as predicted, and the telemetry shows that the IDD's final position is spot on.

Now we just have to drive it. We've already put in a couple of days' work on the drive sequence, which is a good thing, because this one's going to the testbed for sure, later today.

Even with that testing, Ashitey expects me to be pretty worried about this -- "You won't sleep well tonight!" he laughs.

Won't I? I'm not so sure. "I'm not really that worried about it," I say, realizing it's true even as I say it. "I already told everyone it might take us more than one sol to do this, so it's okay if the target's not reached at the end of this drive. I mean, at this point, we just want to demonstrate that we can do a successful drive without tearing the IDD off." Maybe I shouldn't have phrased it that way, but it's essentially accurate.

Then again, Opportunity's been sitting still for almost 60 sols. Purgatory Ripple was only 40. As long as we get the damn rover in motion, I think some people wouldn't mind if we did tear the IDD off.

But that would disappoint Ashitey and Frank, who are hoping to use it tomorrow to start the 7x7x5+stereo MI mosaic of Upper and Lower Overgaard. (Well, maybe it would disappoint some of the scientists, too.) If we end up doing the whole thing, it'll be the largest-ever MI mosaic of a single object on Mars (obliterating one of my records -- the 6x4x5+stereo on Keystone). "I'm happy I'll be doing the first drive with the arm in this weird pose, but I was hoping to be in on that mosaic," I tell Ashitey.

He commiserates. "If you want it, you won't get it. That's how it works." He feels my pain, since he's been missing out on the cool Spirit drives we've done while he's been struggling with this IDD problem. "They promised me the last half-meter to Home Plate, though," he jokes.

Eventually, our testbed time rolls around, and Ashitey heads down there with Jeng to test our sequence. I stick around the sequencing room for a bit to handle the walkthrough, but then I can't stand it any more -- I have to go down there, too. Before I leave, Rich, the TUL, asks when I think they'll be done in the (notoriously time-eating) testbed. Who the hell knows? I shrug, look at the clock. It's a little after 3. "Uh, 4:27," I tell him.

By the time I get to the testbed, they're just starting to run the sequence. Amazingly, the thing runs all the way to completion without a hitch -- even the tight suspension limits work, at least in the testbed. As we're finishing up and preparing to head back up to the sequencing room, I check the time. 4:25.

I wait two minutes before calling them to tell them we're done.

Despite our success in the testbed, I'm actually somewhat pessimistic about the drive. Larry Soderblom asks me what I think are the odds it will succeed, with Upper Overgaard in the IDD work volume. "Fifty-fifty," I tell him. Then I can't resist completing the old joke: "Either it'll happen or it won't."

"I bet you a beer it'll work," he says.

I have a policy: never bet against the rovers. Besides that, I don't drink. So I'd have nothing to look forward to: either I "win," and get a beer I can't drink, or I lose, and have to buy him a beer. Nevertheless, in the spirit of camaraderie -- what the heck, just this once, I accept the bet.

[Next post: sol 732 (Opportunity sol 712), January 23.]

Courtesy NASA/JPL-Caltech. The IDD in the "thinker-stow" position.

Opportunity Sol 706 (Spirit Sol 727)

2011-01-18T19:54:00.000-08:00

Opportunity's start time is sliding later, thanks to the Earth-Mars day-length difference, but it's not late enough yet that I can actually come in to work any earlier -- between 9:30 and 11:30, there's no parking to be had.

As a result, I'm in a couple of hours before we actually start, and this gives me time to check out Ashitey's meeting with Erickson, Callas, Eric Baumgartner, Joe Melko, and so on, about the current state of the IDD investigation. The first question is whether we should finish the mini-Martian-tai-chi (our cute name for the recalibration activity we were doing) before stowing. Nobody wants to bother; they just want to get the damn arm stowed so we can drive. So much for that.

Next question: is it OK to increase the rotor resistance for the duration of the stow? This resistance value is the thing that lets us work around the broken motor winding, and which had been preventing stalls until this weekend. Eric's take on this, which mirrors email he wrote over the weekend, is that this will be fine. They'd worked out the present value partly empirically, and everyone's willing to believe that we simply needed a little more margin in that number.

What else do we need to do to get ready to drive? We won't be driving today -- we're just going to stow the IDD in its new stow configuration -- but it's what everyone's gearing up for. First, we have to make sure we're not driving over anything too big. Ashitey negotiates a slight relaxation of the definition of "too big," but we're still left with this rule: the front and middle wheels can't go over anything bigger than 3cm; the rear wheels, 4cm. This is about what I'd already planned for, so no problem there.

Next, we have to set up the new stow parameters. The FSW's Fault Protection code has a feature where you can tell it what joint angles represent a stowed IDD and have it check constantly whether we're in or out of bounds; if we're out of bounds, it will stop the drive. We never used this on Mars, because when the IDD is stowed the normal way, it hangs securely onto a hook. But we'll be setting it up today.

Finally, Ashitey suggests reducing the wheels' max speed by 66%, on the theory that that should make us come off of an abrupt drop (if we screw up and have one of those) a little more gently. To my surprise, this is rejected: the rovers already move so slowly that there's little to be gained by this.

Oh, and we have to clear the errors left over from the most recent stall fault. And Jim Erickson asks me to add a rule to our flight rule checker that warns if you send the "stow IDD" command on Opportunity, since what that command does is no longer what we want to do.

That's all for the meeting. As was the case Friday, the sequencing itself is simple. Today it's even simpler, since we're basically just repeating Friday's sequence (after clearing the errors and increasing the rotor resistance). But, once again, it's worrying about the upcoming drive that consumes the greater part of the day.

First, Ashitey relays a concern from the science side about closing the APXS doors. You close the APXS doors by rotating the turret to one of the extremes, and in the new stow configuration, we're commanding it pretty close to that value. In addition, the wrist and turret have more "play" than the other joints -- they'll jiggle around while we're driving -- and we might therefore end up crossing over the line we're starting so close to. This is worrisome because the doors are so hard to get open once they're closed. That wasn't always the case, but we started having trouble with it on the surface, so we decided just to leave the doors open permanently. What happens if we inadvertently close the doors and can't get them open again? We effectively lose that instrument, and with it the ability to sense the chemical composition of rocks and soil.

But we're dealing with a failing mechanism here, and we need to make some hard choices. And that's the risk we decide to take.

We also spend a considerable time working out the suspension limits. We frequently set these limits, especially on Opportunity (come to think of it, I don't know if we've ever set them on Spirit), to help us decide whether we're crawling over something bigger than expected. So in theory, we should be able to just work out how much a 3cm or 4cm rock would articulate the suspension, poke in those limits, and proceed with a bit of extra insurance.

The problem is that, as with so many things we do, this is beyond the limits of what the hardware is rated for. The potentiometers that sense the suspension aren't accurate to more than 2 degrees or so -- they're not intended for this level of precision -- and a 3cm rock changes the rocker differential by a little less than that. Ashitey wants to be fairly generous with the limits, but I don't. "We've already sold everyone on the concept that this might take us a couple of sols here," I point out. "We might as well be conservative." We add a little margin, but it's still possible we'll stop for no good reason. So be it. I'm getting paranoid.

By the end of the day, we've got a pretty decent drive sequence. It's not terribly complex; it's another one of those sequences with a high discussion-to-command ratio. But that's okay. We're doing something new and weird, and we can screw things up that we could never fix again. So the more talk, the better.

But first let's just hope we can stow the damn arm, so that we can find out whether this even works.

Opportunity Sol 702 (Spirit Sol 723)

2011-01-14T17:16:00.001-08:00

Because Monday is MLK Day, we're doing a 3-sol plan this weekend. We expect it to be fairly simple, if a little scary: we're putting Opportunity's IDD in its new stowed configuration today. This is the "Rodin's Thinker" pose: the IDD will be swung up over the solar panels, elbow-out, with the turret resting about 5cm over the left front solar array hinge. Ashitey's worked everything out in the testbed, where they've even tried driving in this configuration. But it's scary all the same.

Actually, just putting the IDD in that pose won't be scary -- driving like that will be.

Anyway, our day will be relatively simple. Unlike Spirit's. Spirit has turned around to IDD the chewed-up Paso-Robles-like stuff she turned up while climbing Husband Hill. This stuff appears to be salts, and since salts are mobilized by water -- you know, the stuff we're here to find evidence for -- most of the science team is hopping-up-and-down excited about it. (Though not Larry Soderblom, who dismissed it in email as "bright dirt." He thinks we should spend this time zooming toward Home Plate, as we're increasingly behind schedule. I can't say I think he's wrong, but I'm no scientist.) And they're doing one hell of an IDD campaign, some twelve targets or so over the 3-day weekend.

John Wright's the RP-1, so I have no doubt it'll get done, and get done well, too. But people keep asking me, "Aren't you glad you're not on Spirit?" And I have to tell them no. Truth is, I wish I were John. The harder the task, the greater the glory.

I guess I'll have to let him have a little glory.

Since we have a lot of time, I go ahead and get to work on next week's drive. I expect a lot of scrutiny, so the earlier I get a handle on this, the better. Happily, Ken Herkenhoff is out here, so I discuss the bump target with him and Wendy Calvin. They want us to get to a pair of rocks -- "Upper Overgaard" and "Lower Overgaard" -- that are slightly ahead of us and to the right. Before going there, we need to back up 1m and image the outcrop we've been parked in front of since the IDD anomaly.

Normally, this would be trivial: turn on visodom, back up, take our pictures, turn, and bump forward to the new target. But, oh, the restrictions we labor under now! In addition to the limitations we already have when driving Opportunity -- the requirements for periodic slip checks and the problems induced by the failed RF steering actuator -- we have new restrictions caused by the IDD's new stow configuration. In particular, we've decided we can't tolerate a drop of more than 3cm, as this might cause the arm to jounce too much and whack the turret against the solar panel. So we can't drive over anything bigger than two or three centimeters -- in common units, about an inch.

You think there will be anything bigger than that between us and Victoria Crater, still some kilometers away across Meridiani Planum? Naaahh ....

And, of course, since we're also restricting the IDD's azimuth -- to ensure that we can still drive even if it fails altogether -- we have to really nail the drive.

And there are a couple of obstacles of just the right size, right where we need to go. Of course. (And there is no position that gets both Upper Overgaard and Lower Overgaard into the new, sharply narrowed work volume, without doing something like driving way around and approaching from a different direction. Which we won't.)

So I have to plan the drive very, very carefully, and one crazy thing I come up with is not to use visodom. This is something of a gamble, but I think it's a sound one. Our slip is likely to be low, and it will carry us mostly away from the many 3cm-or-larger "obstacles" scattered all around us. It might mean we need an additional sol for fine positioning, but I can sell that. Everyone's so happy to be moving at all, they'll buy it. The alternative is to risk a bad visodom position update that would cause the rover to drive farther than it's supposed to, climbing the obstacles and possibly forever damaging the arm.

Did I say I wanted this to be hard, to increase the consequent glory? I take it back. Less glory, please.

Just as we're wrapping up for the sol, about 7 PM, we get the downlink from yestersol. I take one look and sigh. "Bad news, everyone!" I announce. "The last sequence faulted out near the end, during the return to the ready position." I hope this is another joint-1 stall, as opposed to a completely different problem, but that data hasn't come down yet. "So the stow sequence we built today won't execute over the weekend. Worse, the MB is aimed directly into one of the HAZCAMs." This is a condition we're supposed to avoid; the instrument's radiation source can damage the cameras.

So should we try to recover? Luckily for us, Jake Matijevic is still here. Jake gives us a pass on the MB situation, pointing out that the MB's radiation source has degraded significantly since we got to Mars, and at its current distance from the cameras, it should no longer be a threat to leave it like this for a few days. Emily decides not to reassemble the team at this point to try to fix the problem, especially because, due to missing data in the pass, we don't even know exactly what the problem is yet.

So we go home. I can't help thinking that one consequence of this fault is that it'll be at least one more sol before we can stow, so at the earliest we'll drive Wednesday instead of Tuesday (the day after the holiday). Depending on the analysis, we might have to push the drive later than that. And since I'm on Opportunity only Tuesday and Wednesday of next week, that means I might not get to do the first Mars drive in the new stowed configuration.

Hey, I want a little glory. I'm only human.

[Next post: sol 727 (Opportunity sol 706), January 18.]

Opportunity Sol 701 (Spirit Sol 722)

2011-01-13T16:36:00.000-08:00

This was not a big sol. We were planning to do some RAT bit imaging, but that got scrapped at the SOWG meeting.

"Just so you know, we need to do the RAT bit imaging before the next time Opportunity uses her RAT," Emily Eelkema pointed out.

But, somebody replied, Steve's position was that "the next time the RAT comes out will be at Victoria Crater."

"I guess we've got some time to do the imaging, then."

And that was about that for that.

Still, we at least had something to do -- namely, we did more tai chi. The latest results showed about a 7mm discrepancy between the predicted position and the position computed from the images -- within our error budget, sure, but there's room for improvement all the same. So thisol's big IDD activity will be to move to the image-computed positions, take images there, and run them through the stereo correlation again to help with the (potential) recalibration.

It's not much to do, and delays elsewhere in the process make it a fairly slow day. This is a good thing, as it gives Matt Heverly, who's shadowing Ashitey thisol, a chance to really dig into the sequence. Indeed, Ashitey has Matt pretty much build the sequence from scratch, then disappears. Matt and I take the time to go over everything in the sequence in great detail, a good learning experience for him (I hope).

Life in the Land of Opportunity will stay slow until we start driving again, which could be this weekend but likely won't be until next week. Our next drive target is Overgaard, part of the same outcrop we're studying now -- the drive will of course be a very short one. But it's still important and interesting because PCAM imaging revealed "festoons," little smile-shaped ledges that are strong indicators of past liquid water. So compelling is this evidence that Emily refers to Overgaard as "the Holy Grail of Meridiani Planum."

"I thought that was Victoria Crater?" says Wendy Calvin.

"That's too far away," Emily says simply. "Let's focus on the present."

Victoria Crater is indeed far away. But so were the Columbia Hills when we started driving to them. Behold the triumph of persistence.

Opportunity Sol 698 (Spirit Sol 719)

2011-01-10T14:38:00.000-08:00

Ashitey's already seen the IMAX movie -- he saw it this weekend. "It was okay," is his review, though he's more enthusiastic later when discussing it with Squyres. They both got to see it because they helped -- Steve, by being in it; Ashitey, by running the testbed's RAT and PMA actuators so that the movie could use realistic sounds.

Opportunity (I'm back to the other side of the planet) doesn't have much to do today. We're not driving yet; that gets pushed back about two weeks every two weeks. No real science-related IDD work, either, though we're doing a miniature version of the "Martian tai-chi" IDD recalibration. Not because we really think we're out of calibration, but because people keep asking Ashitey about it at the IDD anomaly meetings, and he wants to have something to tell them.

So it's a pretty easy day on Mars.

Before leaving, I get into a discussion with Chris Leger about the Spirit driving plan. We've been trying out these two-sol drives with an autonav-only drive on the second sol, but they haven't been working out too well, and he's worried that the time we spend on them gains us little and costs us a lot of attention that would be better spent on the first sol's drive. I don't quite disagree with this, but I think he's a little too pessimistic. All of our techniques start off with large investments and little initial return, but we rarely regret developing them. I see this as being another instance of the same deal. He doesn't quite disagree with that, but we both have the "I don't disagree, but let's both agree that I'm right" disease, so the conversation limps along a lot longer than it should.

Fortunately, it's interrupted by a phone call from my parents, telling me excitedly that they just saw me on the CBS Evening News. (It still hasn't aired out here, so they also want to let me know so that I can catch it.) I filmed an interview with a news crew last week, and I was just going to record it on the TiVo and send DVDs to the family as an FYI. But it turns out they caught it when it aired. Funny thing: when I'm on the phone with Dad and Trish, Roxanne[1] calls to tell me the same thing. Who knew that many people watched the CBS Evening News? Apparently, it's some kind of big deal or something.

When I get a chance to see the interview myself, I'm relieved. I didn't really feel that it went all that well, but the piece came out great, and I even look like I know what I'm talking about. Good editing, I assure you. I expected the two-and-a-half minute piece to be two minutes and fifteen seconds of Squyres, then ten seconds of Nicole (whom they interviewed about naming science targets) and one shot of me saying "It's great!" It turns out to have less of Squyres, more of me, and -- erk -- no Nicole. Well, that sucks, but it's America's loss.

[Next post: sol 722 (Opportunity sol 701), January 13.]

Footnotes:

[1] My then-mother-in-law.

Spirit Sol 714

2011-01-05T11:20:00.000-08:00

"Our objectives today," Steve announces, "are to drive like the wind and then get the uplink team home in time to watch Texas beat USC." It's Rose Bowl Day, and Steve, in case you hadn't guessed, is a Texas fan.

Spirit made a respectable showing for her second Earth-birthday: 65m, most of it in the direction of Home Plate. It's not as terrific as I was hoping for, but it's sure not bad. Slowly but surely, the drive-metric graph is starting to look less scary.

She made it a good chunk of the way through the dune field that yesterday lay between us and Lorre Ridge, but a slip check measured 70% slip -- apparently real, not a visodom artifact -- and stopped the drive a little earlier than it would have otherwise.

Looking at our tracks, we can see that we really are slipping a lot. Rather than leaving nice, widely spaced cleat marks, the wheel tracks are all bunched up. However, we're not digging in, so Chris and I agree that it's safe to drive away.

Which will be fun. The path out of the dune field is relatively obvious, and firmer terra (marsa?) is only about 12m away, but on the way is a 30cm rock pile we definitely don't want to climb. With that, and the fact that we're slipping so much, there's only one way out: visodom. It'll be slow, but we've got a whopping four hours to drive, so we've got plenty of time for it. And after that we have a short blind segment followed by autonav until the time-of-day limit. (I'd rather spend the four hours on an 80m blind drive followed by a three-hour autonav segment, but we aren't in that kind of terrain. Mars wins.)

And there's something we need to do before we even get on the road. For the last few sols, we've been getting intermittent stall warnings from the left front wheel. We got another batch yesterday, and Matt Heverly and Terry Huntsberger work out that it happens whenever autonav decides to take a sharp left, meaning that that wheel is steered almost to the extreme counterclockwise position.

This probably isn't a failing actuator, but it could be. More likely, it's either a miscalibrated actuator or some junk physically jammed into the wheel. Hoping for the former, we start the drive with some commands to recalibrate the wheel, steer it to the troublesome position (to see if we get more stalls), then straighten the wheels and install new soft-stops that will prevent Spirit from steering that wheel back to the position where we get the warnings (for the rest of the day, giving us a chance to look at the data before she tries to go there again). If we see no warnings tomorrow, then the recalibration likely fixed it. If we do see warnings, well, we'll make the new soft-stops permanent. The new limit is only about one degree away from the old limit, so that won't compromise Spirit's driving appreciably anyway.

All the same, I'm hoping it'll go away and stay gone. One rover with a bad steering actuator is plenty.

[Next post: sol 719 (Opportunity sol 698), January 10.]

Courtesy NASA/JPL-Caltech. Spirit's tracks look a little closely spaced -- this is different terrain, probably with somewhat looser soil, than we normally drive her in. Still and all, though a little worrisome, it's traversable.