Spirit Sol 755

The plan for today is to back away from Posey and drive up onto the rim of Home Plate. If everything breaks our way, we'll be able to see over it tomorrow, and we can decide whether to drive across the thing or around it. I'd been hoping all the way to Home Plate that it would turn out to look like a salt flat, and we could just zoom across it -- an easy 100m day. But we've had a couple of glimpses over the rim already, and it looks like it's pretty gnarly up there. So going around might be better.

Terry and I separately roughed out a drive path, basically following a route that John spotted when we first drove up here. And since Ashley hasn't been getting much practice as RP-1, I offer her the big chair.

I have a small regret about this decision. On the schedule, Antonio's supposed to be shadowing today, and he gets less coaching and instruction this way. Well, I'll try to remember to give him some extra opportunities next time I work with him. He turns out to be very useful as an analyst, though; we find a couple of rocks whose size we can't evaluate from our current position, and he goes through more than ten sols of prior imagery until he finds a view from which we can prove they're safe. That probably saved us an hour of work right there, and might have even salvaged the drive itself.

Ashley, for her part, does well with the sequencing. We underestimate how long it's going to take, though, and we aren't really ready at the walkthrough. We catch a lot of errors -- so many that we basically have to go back and walk through it again. But I feel pretty good about the end result.

The drive uses visodom virtually all the way to the top. Visodom is especially necessary for the first leg, where we need to get onto a very narrow path leading to the rim. To our left, the terrain slopes away much more steeply; to our right is a rugged outcrop. But in between is a straight, relatively smooth path that was practically made for our rover, it seems. The tilt gets pretty bad up there, though, maybe bad enough to stop us early. We'll see when we get the data.

For the very last meter and a half, part of our view is blocked by an 11cm rock -- not big enough to be scared of, but big enough to obscure the terrain behind it from our current vantage point. So for that part, we turn on autonav, and turn off allowing autonav to drive backward -- something we haven't done for a long time on this vehicle, if ever -- because we don't want it going back down the slope.

The drive distance is relatively short, but the sequence itself is a pretty complex one -- just one of those that need painstaking attention to detail, all the way through. I hope we didn't miss anything, but I don't have a bad feeling about it.

Maybe I should have a bad feeling about that. But I don't.

[Next post: sol 757, February 18.]