Spirit Sol 44

Today's my day to come in early to support the megadrive. Between getting home late and needing to return early, I only had about four hours to sleep. And I slept for only half of that, waking early because I was stressed out about the sequence.

I listen to the radio in the shower. I hear a funny BMW commercial comparing BMWs to a Mars rover. Still, I know which one I'd rather drive.

We're also on the news: KNX reports on Opportunity's trench-digging, and on our attempt -- the one we'll make today -- to set a Martian distance record.

I arrive not long before 11:30 rover time, when the first data from the morning activities is scheduled to arrive. We end up getting MI images -- which confirms that the morning sequences ran to the end, or nearly so. Shortly after that, we get confirmation that we drove!

This alone means that a lot of things went right. If we drove, then the IDD sequences -- which were planned two days before, and which executed this morning before this morning's drive -- completed successfully, and the IDD stowed. Plus, at least some of the drive sequence obviously executed.

That's the good news. The less good news is that the autonav didn't happen, which means that the drive didn't run all the way to the end. This causes some consternation, until we deduce the cause. Apparently, we set the mobility time-of-day limit -- a kind of reverse alarm clock, which tells the rover when it's time to stop moving -- about 20 minutes too early. As a consequence, the rover stopped moving just at the end of the blind drive, as it was turning toward Bonneville. We got about 18m as it was, but if we hadn't messed up the time-of-day limit, we'd have driven another 5m, maybe further.

But as it is, we still made a lot of progress -- including the longest directed drive ever on Mars -- and the rover is alive and healthy. So we can do our afternoon drive, which will let us set another record -- the longest one-day drive -- if we do it right.

MIPL pops out a terrain mesh in no time. We check with the uplink team. We've got about 30 minutes before we need to start uplinking our sequences. "Ah, no problem," I tell them.

Because of a second mistake, we have no post-drive NAVCAM images. This leaves us with only the HAZCAMs, and therefore we can see well enough to drive only a few meters ahead. This limits our options, but sometimes that's a good thing. We don't have time to explore a lot of options anyway.

Mark and Chris and I find the cleanest path through the terrain we can see, and we prepare the sequences we need. We're done with about 10 minutes to spare, which is actually more margin than I was expecting. Just as I'm about to deliver the sequences, Mark reminds me that we need to clear the goal error that was set when the rover ran out of time; if we don't, Spirit will refuse to drive. "Yes, I was just on my way to do that," I say nonchalantly, scurrying back to my workstation.

Well, still, we have five minutes to spare. I hand the sequences over to the uplink team, and as they get to work, I spend the remaining time indulging my paranoia, checking things that I know perfectly well are just fine and don't need any checking. One of the things I check is a list of sequences that got uplinked this morning, to see if all of the megadrive-related sequences we need actually made it to the rover.

That's funny ... I don't see some of the sequences that were supposed to be there. I check the list a couple of times, sure that I must be overlooking something. But I'm not. Three sequences are missing.

The three missing sequences prepare the rover for its drive and clean up afterward. If they're not there, the rover will still execute the drive sequences we're about to send, but without preparing itself properly. I'm not sure what the results of that will be, but they won't be good.

I ask around, and indeed, those sequences are missing. At the very last minute, we locate them, prepare them, and send them up along with the drive sequence. Disaster averted.

"How did you notice that the sequences were missing?" Celina Garcia asks me. I explain that I'm ridiculously paranoid, and that my paranoia just gets worse every time something like this seems to justify it. "I'm still barely functional as a human being," I tell her, "but a few more cases like this and I won't be any more."

With the excitement over, there's nothing to do but wait. And wait.

One good result of arriving so early is that I'm there for the lunchtime science briefing. Today it's by one of the Atmospheric Science guys, Mike Smith, who is very funny. You have to have a sense of humor to be an atmospheric scientist on this mission; relatively speaking, they get no respect. But they take it all in stride, and Mike talks about the science they've been able to do, watching how the temperature changes at different levels of the atmosphere over time. In a few days they'll have a simultaneous observation with MGS -- we'll measure the atmosphere by looking up through it at the same time they do a measurement looking down, flying over us. This is very similar to the flyover we did with MEX early in the mission.

We've got a while before anything will change -- there's no new data yet, and the downlink assessment meeting hasn't happened. Now that I've relaxed a little, I realize that I'm hungry, and the reason why occurs to me. I've been so busy that I haven't eaten for more than a day. I go out and get chicken strips from Jack in the Box, which are not bad at all, assuming you're hungry enough.

I'm back just in time for the downlink assessment meeting. The top story is that the MTES checkout sequence -- the one that was running when Spirit had its anomaly, and which never completed -- has now been rerun, and completed successfully. This means we can do nighttime MTES science, which makes the atmospheric guys very happy.

LTP reports that we've traversed 59.3m, plus today's drive. (Opportunity has driven 35.3m.) This is good, but still a long way from minimum mission success, which is 600m between the rovers. We've got a lot of driving left to do. Tomorrow will likely be a touch-and-go, once more driving toward Bonneville. We'll likely continue in this vein for a while, alternating touch-and-go drives with megadrives.

The scientists also present an MI image showing the MB's imprint in the wheel tracks, a target called "Mimi Tracks 2." This is an image from sol 42, the day of the unusually complex IDD sequence. (Actually, I think the image was taken on the morning of sol 43, but whatever.) You can clearly see the imprint we left in the soil, even including a relief of the small depression at the tip of the MB. I'm very happy for the scientists, who say the image is "incredibly interesting" and will keep them busy for months, maybe years, analyzing the soil's physical properties. I'm also relieved: I almost gave up on this target, since it was in a tricky spot, almost impossible to reach, making the sequencing inordinately complex, and we were so pressed for time that evening already. But I stuck with it, and found a way to make it work. Mimi Tracks 2 was also their third choice -- they had picked two other soil targets which were not clearly reachable by all of the instruments they wanted to use, and Bob Deen suggested that they choose a target that we were more certain to be able to get. Good thing he did so; we might have lost a valuable science target if he hadn't noticed the problem.

Courtesy NASA/JPL-Caltech. The MI image of the target "Mimi Tracks 2," showing the effect of pressing the MB instrument's donut-shaped "nose" into Spirit's tracks.

The Odyssey pass is coming, so I go to the SMSA so I can be there when we get the data. The longest one-day drive on Mars so far is 24.382m (set, I think, by Chris Leger, just a few sols ago). When we get the data, we find that indeed we've beaten the record, driving over 27m today. Mark reports this as "a new otherworldly record," and Joel Krajewski offers his congratulations. Andy adds that tomorrow, we should beat Sojourner's total distance record -- 17m to go.

A lot went wrong today. We lost time from setting the mobility time-of-day limit too early, from failing to uplink sequences in the morning (so that we had to uplink them just before the drive, at a much lower rate, cutting significantly into our afternoon drive time), and from not having the mid-drive NAVCAMs, which kept us from planning a long blind drive in the afternoon. And a couple of other things, too. All put together, this kept us from getting the 50m we should have gotten.

But a lot went right. All of the mistakes were minor, and were mostly understood and corrected, and we tested the megadrive approach. We learned everything we needed to learn in order to do it right the next time. And we did set a new distance record. I call it a "mini-megadrive," and the term seems to catch on. Jennifer uses it later when reporting on the sol's activities to the scientists, and it gets a tension-defusing laugh.

Tomorrow will be a fairly routine touch-and-go. We'll explore the soil we happen to be sitting on top of, then drive more. Andy is the TUL for the evening, and in the SOWG, we both push for a longish drive so that we can break Sojourner's record. I'm surprised -- but pleasantly surprised -- to see Andy pushing for it as hard as he is. I assume he's not the TUL tomorrow and therefore wants to be involved in breaking the record as much as I do. He has to talk fast in order to make it happen -- when the scientists have cut tomorrow's science as far as they can and are on the brink of cutting part of the drive, Andy talks them into giving up the evening DTE comm session instead. It won't return much data, and it's only an hour or so before the UHF pass, he points out, and we'll get all the data in the UHF pass anyway. They buy it, and the drive is on.

The sequencing itself, which would have seemed dauntingly complex just a few days ago, now seems a doddle. It's in decent shape when I hand over to John -- early, for once -- and I can actually relax a little and listen to the midnightly science briefing. This one's on dunes, and it explains why they wanted measurements of both the crest and the trough of that dune-like thing we examined a few sols ago (seems like forever, now). They were trying to tell whether it was a dune or a ripple. The distinction depends on measurements of the particle sizes at the crest and trough of the bedform (the generic term): ripples have larger particles at the top and smaller particles at the bottom, while dunes' particles are too large to make it to the top. The conclusion: it was a ripple. Don't ask me the larger significance of this, because I don't know (though I'm sure there is one). To me, it just seems like a cool thing to know.

I stick around for a few hours after my shift, so that I can put together our next software delivery. This takes longer than it should (doesn't everything?), so that by the time I leave I've been there 18 hours on about two hours of sleep. I go home and sleep as long as I damn well please. It feels wonderful.

No comments: