Spirit Sol 215

This is my first RP-1 sol since I-don't-know-when, and moreover I'm doing it solo -- the scheduling snafu left us no RP-2, though Chris is here as a "floater."

I'm so happy.

It's still shaping up to be a simple sol, a MB-to-APXS tool change. Since we're in this weird out-of-phase part of the daily schedule, they haven't even uplinked yesterday's sequences yet, which means I have time to fix something if it's wrong. But I check them out, and to my surprise I can't find anything wrong with them. There's stuff I'd change in retrospect, but nothing really wrong. So I leave well enough alone.

Anyway, I've got thisol to worry about. It might be simple, but I don't like to procrastinate, so I go ahead and whip out the sequence.

Then we get the sol-213 downlink. Just as no plan ever survives first contact with the enemy, so thisol's plan will not survive first contact with the downlink. The joint angles from sol 213 were very close to the predicted values -- that is, the IDD went just about exactly where we asked it to go -- but the APXS contact switches report no contact and the APXS dust door reports that it's still closed.

Which is mildly bad. The APXS dust doors have to open in order for the scientists to get good data from the instrument. If they're not open, we'll have to redo this observation. We can't redo it on this exact spot, since we're going to RAT it on 214 -- unless we try to modify the sequence before uplinking it a few hours from now -- but that will be OK, since we'll get effectively identical results by just APXSing other parts of the outcrop. We can do that without even driving. And anyway, the doors might be open even though the rover says they're not -- on Opportunity, the switches are flaky, and maybe Spirit's switches are starting to get flaky, too. If so, the APXS observation will be just fine; we'll know when we get the results back later tonight. So it's not the end of the world.

But it does leave us with a puzzle: why did the IDD stop moving? Normally, the IDD will stop moving for one of three reasons: it reaches the commanded position, one of the instrument switches reports contact, or the joints draw more current than allowed (suggesting an unexpected contact). It came close to the commanded position, but didn't quite make it there, so it didn't stop for that reason. The switches report no contact, and the joint currents were well under the limit.

So it shouldn't have stopped. But it did.

In a sense, it doesn't matter. The IDD ended up in the right spot -- more or less -- didn't it? But it's a mystery, and engineers can no more ignore a mystery than they can stop breathing. So Rich Petras and I start trying to figure it out, and we end up sucking in Jessica Brooks and Jeff Favretto and Jeng Yen and some other people. Maybe the APXS contact switches were disabled? No, they're enabled, and anyway we'd see evidence of the switches tripping even if they were disabled, and we don't. Maybe the switches tripped long enough to stop the IDD but then "untripped"? No, we'd still see the temporary trip in the downlink, and we don't. Maybe we don't have all the data from the pass? No, then the data product would be marked as partial, and it isn't.

Oh, hell. We give up and call Bob Bonitz. For once, he doesn't know either, but he does move us forward a step. It looks like we did some calculations incorrectly, and the IDD might think it did reach the commanded position after all.

That's good enough for me. Well, no it isn't, but I have to get back to other work, so it will have to do for now. The other work I have to get back to is related to the fact that the APXS doors aren't known to be open. To avoid contaminating the APXS, we're not supposed to RAT with the APXS doors open. The sol-214 IDD sequence closes the APXS doors before doing the RAT brush, but sometimes the doors open only partially, and then the door-close move doesn't work (you have to open the doors fully before you can close them). So we might be about to RAT with the APXS open. Two hours to uplink ....

The science team decides to take the risk of the doors being open during the RAT brush, so we won't need to change 214 after all. But if the doors are open during the 216 RAT grind, that would be bad. So thisol -- 215 -- we'll have to open the doors fully, so that they'll close when we tell them to. This involves a maneuver that opens the doors on the CCT, a calibration target mounted on the rover's underside.

"Is that going to be a problem?" asks a worried-looking John Grant.

"No," I say cheerfully.

John relaxes instantly. "I love it when he says that," he says.

Changing the sequence takes only minutes. Then I realize that since we're now bringing the IDD up to the rover body, we can take a picture and see whether the doors are open. I throw that in too, for good measure.

And I'm pretty much done for the sol. I start both RP workstations rendering movies for the uplink report and kick back a while. Frank swings by, trailing a huge tour group consisting mainly of Japanese graphic artists and animators -- all SIGGRAPH contacts -- and I tell them a little about what's going on. They're all very polite and thank me profusely, and I kick myself for not remembering how to say "You're welcome" in Japanese. ("Dou-itashi-mashite," dumbass.)

Anticlimactically, I don't get to see the day quite through to the end. Just when the CAM starts, I have to go upstairs for a Change Control Board meeting -- management approval to deliver a slightly updated version of RSVP. Since I can't be in both places at once, Chris helpfully comes downstairs to handle the CAM.

Darn, and I really wanted a challenge.