Spirit Sol 694

In summary: a good drive, but not great. We made 30m of progress, carrying us all the way to the ridge. But Murphy's Law is interplanetary, and visodom failed to converge during Spirit's top-of-ridge slip check. Which, thanks to our increased paranoia, meant she stopped driving.

As it happens, she probably would have stopped driving shortly after that anyway, since there is a rough semicircle of autonav-unfriendly tilts just a couple of meters below us. However, it's something we feel comfortable blind-driving through.

In fact, as we look down the ridge and across the terrain separating us from Comanche, it looks like we could blind-drive across the whole thing. It's a total of about 40m to the base of Comanche, and there are hardly any obstacles at all. They've allocated over three hours for driving again thisol, and I end up giving most of it back.

(The scientists have no problem figuring out what to do with the time, though. Turns out we're parked on the largest expanse of outcrop they've yet seen at Gusev, so they pack in plenty of PCAM and MTES imaging of it before we leave it behind forever. We'll also be taking a couple of pictures and relaying them through MEX as a friendly bit of international cooperation. Since our European friends plan to show them off, as one person notes, "Let's make 'em pretty." We settle on a nice color PCAM of Comanche and an NCAM of the intervening terrain. Should look pretty darn cool.)

The nice straight path makes the sequencing simple as well, which leaves me time to get lunch. As I'm walking over there with our prodigal son, Mark Adler, I ask him what impression he has of how MER's changed since he left.

"There's a lot of automation," he says immediately. "It all runs really smoothly. 'Course, if something goes wrong, well, that's a runout sol."

He's right about the increased automation, but as to the rest, I don't remember the last time an automation failure led to dropping the plan and executing the runout. I don't know if it's ever happened. We don't have the kind of team that likes to let it happen.

Another kind of automation failure gets us worried, though -- at one point, the file server freezes for a few minutes. We can't do anything without it, so this brings the process to a grinding halt. Fortunately, it comes back after a short delay, and the ball resumes rolling.

While all this is going on in the Spirit World, Opportunity's been making progress of her own. Slowly but surely, they're performing a limited IDD campaign on the juicy bit of outcrop we parked in front of, lo, these many sols ago. In the process, they're learning about the fault, and one of the things they learned yesterday is that the amount of resistance caused by the broken wire isn't a constant. Instead, it seems to vary as the arm articulates.

But the way they found out was by having another joint stall, so they're in the middle of a tool change -- with the MI pointing straight up and its dust cover open, to make matters worse. It was supposed to be a skip sol, but they need someone to help them recover and get things back on track. And who just became available, but little old me?

So I go upstairs and help Ashitey sequence the recovery tool change. It's not quite the first time a rover driver has worked on both rovers in one sol -- if nothing else, Cooper did it when the rest of us were in Hawaii -- but it's the first time I've done it. ("A personal best," as Emily Eelkema puts it.)

Two Mars rovers in one day, baby. It's every geek's dream.

[Next post: sol 697, December 19.]