Spirit Sol 639

Ahh, it's one of those sols where we don't have to start until noon. Oh, my, this feels wonderful.

"I got to sleep until ten today," I say blissfully to Saina.

"I can't sleep until ten," she says. "I get bored."

Which makes no sense to me. But there's not much time to dwell on it; we've got a rover to drive.

About 25-30m away from us, the terrain slopes down more sharply. We can't see over this lip, so we don't know if there's a safe path to Haskin Ridge from here. So our plan is, naturally, to drive to the lip and peek over. If we like what we see, we keep going; if not, we'll have to head most of the way back up to the summit and find a different path down.

Between us and the lip, there's another problem. About 15m from here, there's a series of obstacles that cuts across our path. To the left is a ridge; to the right is a knoll -- which is, perversely, both too tall and too narrow for us to climb.

And straight ahead is a rock. The rock isn't that tall, only about 10cm on the face we can see. But because of the shape of the terrain around it, we can't tell what the terrain looks like on the far side, meaning we can't tell what slopes or dropoffs the rover will experience as it climbs over. The first point we can see beyond the rock is 30cm below the rock's top, meaning the rover could potentially experience a dropoff of that size, and that's too big for this vehicle.

The solution: let the rover handle it. Our plan is to drive Spirit about 11m straight toward the danger area, then turn on autonav and let her find her own path through. (Starting autonav a few meters back from the hazardous area means she can see more of it, giving her a better chance to find a passage.) If she finds a way, great. If she doesn't, then at least tomorrow will bring us better images, which we can maybe use to blind-drive past this troublesome area.

[Next post: sol 642, October 23.]