Spirit Sol 749

I'm on Spirit today, and Spirit doesn't start planning until 13:00. But I don't get to sleep in: since I'm also an Opportunity driver, I have to come in early for a meeting about Opportunity's drive strategy and the latest on the stow/unstow business.

It sounds to me as if the Opportunity science team hasn't yet grasped the consequences of our situation, or isn't that gung-ho about getting south to Victoria, or some of each. Squyres wants to "turn the keys over to the rover planners," as he's put it, and let us book to Victoria as fast as possible. I'm sure that at least part of what's behind this is to try to get us to that crater, the so-called geological promised land, while we still have a working IDD.

But the near-term consequence of this choice would be that we'd likely bypass Payson, a juicy chunk of outcrop in a corner of Erebus Crater. And the rest of the Opportunity science team doesn't want to give that up. Instead, they want us to descend into Erebus Crater, wade through tens of meters of sandy stuff to get to a point from which we can image Payson, then struggle on further to a point from which we can exit Erebus, maybe. Unless we can't exit there, and need to go all the way back to where we started. All this we're supposed to do with an IDD that we have to guarantee we can safely unstow at the end of each drive as we plow through that stuff.

But the science team obviously feels strongly about this. Jim Erickson ducks in to say that there's a rebellion brewing -- the science team against Steve. "We need an answer for them," he says. "Give them time to go berserk, argue, and come to a decision."

We've got a story already: go about 80m south, evaluate the path into the crater, and make a decision there. That'll have to do.

With this and other things, I miss the Spirit SOWG meeting for the first time since I don't know when. (As RP-2, I don't really have to be there, but I don't like to miss them anyway.) But thisol's not complicated, just a tool change. I leave it to Paolo and Ashley to put that together; it's simple and only takes a few minutes. When they show it to me, I ask idly, "So we're not hitting the turret limit or anything, right?"

Paolo brings up the plot of the turret angles, and it shows we're going to 3.15. "Ah, shoot," I say. "Our limit is 3.14."

So they have to do it the hard way, tweaking the target's surface normal and redoing the approach. This takes at least half an hour of tedious work, and Paolo's barely able finish it before he has to rush off to do something else. But he gets it done, and it looks great. We're now going only to about 3.09, well away from the 3.14 value.

In the few minutes remaining before the walkthrough, I sit down to check out the details myself, including running our flight rule checker on it. Among other things, the flight rule checker knows the acceptable turret limits -- which, it turns out, I've misremembered. The upper limit is 3.3. We were fine in the first place. I made Paolo and Ashley do all that work for nothing.

I put the sequence back the way it was, walk through it in that state, and deliver. When Paolo returns, I apologize profusely, but he good-naturedly laughs it off. "It was good experience," he points out. There are sols when we really need to do that, and, as he says, he needed the practice.

Still. I am such an idiot.

Courtesy Wikipedia. Erebus Crater, looking from a distance at the Payson outcrop that was so attractive to the science team.

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