With respect to how long it's going to take us to get down the hill, we don't have a whole lot of experience driving this vehicle downhill -- we've been going uphill for more than a year now. We're going to have to take it carefully at first and learn as we go. I think the deciding factor is going to be how good the geology is. If we're finding geology that offers truly compelling targets (for study) as we found on the way up, then our pace is going to be a lot slower whereas if it's a lot of loose sand and that sort of thing we'll be able to move through it a lot more briskly and head to the good stuff off in the distance.

Steve Squyres