Opportunity Sol 961 (Spirit Sol 982)

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.]

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

Opportunity Sol 961 (Spirit Sol 981)

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)

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)

"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.

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

Opportunity Sol 957 (Spirit Sol 978)

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.

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

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The Mickey Zone of Death!

Opportunity Sol 943 (Spirit Sol 964)

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)

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)

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)

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)

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)

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

"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)

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

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)

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

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)

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)

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)

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)

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.]