Spirit Sol 73

Once again I have a lousy night's (actually, day's) sleep. I keep waking up, thinking of ways the drive is going to fail. There are a lot of them. We didn't correct enough for slip. Or: did we really analyze the depression ahead and to the right of us? Could any nasty surprises be lurking there? Or: if we slip too much as we drive downhill, we'll end up climbing that 20cm rock ahead of us instead of stopping short of it, and if there's a depression on the far side, we could get high-centered on it -- with the rock scraping the rover's belly, and the rover unable to gain enough traction with any of its wheels to crawl back off. Of course, this would mean that our imaging was badly wrong, and our simulations were badly wrong, and our slip estimates are badly wrong. But apart from that, it's very likely.

I obsessively check the flight director's report while getting ready, and am considerably relieved to read that we drove the expected distance and have a scuff mark in front of us. Is it reachable from the IDD? Did we nail the mid-drive imaging? The report doesn't say. But when I get to work and see the results, I'm shocked.

It's perfect.

The scuff is nearly dead center from our final position, with good chunks of it in the IDD work volume. (In fact, maybe all of it is in the work volume; the tool that does the preliminary analysis has some limitations that the shape of the scuff might be exposing.) And the mid-drive NAVCAM, which is a bellwether for the other mid-drive imaging, couldn't be better. The main body of the scuff is right there in the middle of the image. While I'm gaping, John Grant says: "Let me be the first to congratulate you on a perfect drive." When he left last night, he just wanted us to end up somewhere near the scuff. And we executed perfectly. I don't know if it's relief or disbelief, but I can't stop looking at it.

I know I say this all the time, but seriously: I worry too damn much.

I'm not on shift today, Chris is, so it will be his job to IDD the scuff (which has been named "Bear Paw"; targets in it are getting names like "Panda" and "Grizzly"). So I get to wander around and unwind a little before the meetings. Because I didn't come in the usual door, it's not until now that I notice that the beautiful big picture they hung outside our office is gone. Nobody seems to know where it went. Only the tape remains.

But there are a couple of new things posted up in other areas. A copy of the Weekly World News, with its cover story of strange cat-like creatures detected by the Mars rovers, is a favorite. This has been posted in the SMSA (outside of camera range), next to some supermarket flyer advertising, among real items such as $1 calculators, "Mars Water" -- direct from Mars -- for the low, low price of $999,999.99 per gallon.

I take some time to catch up on the images from both rovers. Just as I finish, I manage to delete all the images I've saved for the last week or so. Fuck! I have to go back through the database, digging around for the images I'd liked enough to save. Fortunately, I still have the filenames in an open xterm, and I'd named the files descriptively enough that I'm able to find most of them again.

Correcting this stupid mistake makes me a little late for the downlink assessment meeting. It turns out that Serpent's inner material, while considerably darker than its exterior, is not the same stuff as in the crater after all, so there's little reason to stay. Although, after some debate, they do decide to do a touch-and-go here: they'll look at the inner material quickly and drive on in the afternoon. The target of the next drive, or set of drives, will be -- assuming they can get there from here -- one of the fabled white rocks. This one's been named "White Elephant," and I can't help thinking this is an expression of the attitude the non-members of the White Rock Mafia have toward their White Rock Mafia colleagues.

The composition of Serpent's interior was one surprise. Serpent's outer layer gives us another surprise. Serpent looks like a miniature sand dune (technically, a ripple); we expected it to be soft. But the outer layer is an indurated crust: it's composed of sand, but the sand is somehow cemented. I ask Craig Leff what could be causing that kind of effect; he doesn't know. On Earth, he says, something like that is usually the result of evaporating water. Here, nobody knows what could be causing it.

Courtesy NASA/JPL-Caltech. Holy smoke, it's perfect!

Courtesy NASA/JPL-Caltech. Rover's-eye view from our final position, with the Serpent scuff right in front of us, ready for us to IDD it.

1 comment:

Anonymous said...

Further proof that all a project needs is good people.