Opportunity Sol 804 (Spirit Sol 825)

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)

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

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

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

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)

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)

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)

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)

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.


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)

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

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.