Spirit Sol 797

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.]


[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)

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)

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

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)

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:

  1. Opportunity is healthy. The drive went fine, we just didn't hear the beep that said she heard us.

  2. 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.

  3. 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)

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)

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)

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)

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

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

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

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

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

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

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.