Mars and Me: Spirit Sol 64

Yestersol went damn near perfectly. 35.33m -- a new traverse record! The record-setting drives aren't exciting people as much as they used to, but I'm still happy about it. So is John Grant, who tells me enthusiastically that I did a great job. John also warns me that the NAVCAMs seem to show less benign terrain ahead. Here be hollows.

The big screens in the SMSA are showing the automatically generated "movie" of the autonav portion of the drive. (These are small images, taken 1m apart, showing what the rover saw as it navigated through the terrain.) The cool part is when the rover decides to drive over a sizable rock in its path. It looks like the rock is just under the obstacle size, and Spirit blithely climbs right over that sucker. It's big enough to show up in the ACS data as well; the rover changed pitch significantly while climbing the rock. Bob talked me into doing this last segment of the drive on autonav -- I was going to do it blind, for speed -- but he was right. The terrain is safe, but it was a better decision to have autonav on through here. If only for the movie.

Art wants us to cover another 30m tomorrow. We won't be able to do a two-drive day (the so-called "megadrive" approach), because we don't have comm passes at the right times. But it will be a decent-length drive all the same. Art tries to get me to promise him 30m, but I haven't looked at the data yet, so I don't. He tries again. I still won't promise him, and the second time he gets the message. "See what you can do," he says. Will do.

I guess the scientists' field trip was a short one, because the downlink assessment meeting is full again. LTP (in the person of Dave Des Marais) is enthusiastic about the success of the drive -- "especially in this terrain" (it's rocky out there) -- and has some real praise for the rover drivers. (I can't help it, I'm kvelling.) But they might want to pick a spot to settle down for some IDD work. "We may have to rein in the stallions a little bit," as he puts it. The good news from LTP is that our odometry total now stands at 286m, out of 300m needed to declare success. We'll make it tomorrow!

Tomorrow they plan to do an "air-lite" sol; a downlink-limited day, it will be dominated by a few atmospheric observations plus some driving. Because we're downlink-limited, we'll cut back on the autonav movie, taking an image only every 3m instead of every 1m. Some people would like to cut the movie altogether, but it has an engineering purpose: if the rover errors out during the drive, the movie can be an invaluable forensic tool. The rover has an on-board "fault image queue" that's supposed to be used for this purpose, but Mark Maimone doesn't agree that it's been tested well enough to rely on it yet. So taking the images only every 3m is our compromise, for now.

Since I know what the sol's plan is, at least as far as it concerns me, I leave the meeting and sit down with today's Mobility/IDD guy to analyze traversability. This entails running the navigation images through some of Mark's software, which colors it: green for very safe, yellow and orange for moderately safe, red for hazards. Then you plan the longest safe path you can. I see two good paths in the direction we want to go (northeast) -- one a little more to the north, one a little more to the east. The first path ends up growing on me, because even though it's less direct, it's simpler and safer overall, and we can do the whole thing with the much faster blind driving. The second path is the more obvious choice but has some drawbacks; for instance, near the limit of the NAVCAM data, we'll need some tight maneuvering between a couple of hazards. We'll probably have to leave that to the autonav, and that will eat into the drive time significantly.

Mark calls to see how it's going, and I talk to him about this on the phone; he follows along using a copy of the traversability map he's generated from home. He tells me he doesn't see my preferred path (which I've taken to calling the Northwest Passage), which puzzles both of us. He goes off and looks into it for a while, then calls back with the solution. The person who generated the traversability map I've been looking at did it with the wrong data. The real map has obstacles right where we were going to send the rover. I no longer wonder why Mark works all the time. "You can't turn your back for a second, can you?" I tease him. Of course, we'd have caught the error later in the planning cycle anyway, even without him -- one hopes.

At the SOWG meeting, both Art and John Grant say they're surly. In Art's case, it's because tomorrow's resource picture doesn't look as good as he thought. In John's case, it's because he somehow pissed off a bunch of the scientists -- I think I missed some fireworks by leaving the downlink assessment meeting early today. They needed to cut back on the science observations because they won't have much room in the downlink.

In any case, for planning purposes, everything except the drive is "in purgatory" -- a now-standard phrase meaning that it will make it into the plan if there's room, but you'd better not count on it. John is more blunt than usual about this: "Convince us your observation is crucial for tomorrow, or it's out."

Nearly everything ends up out.

This leads to some acrimony, considerably more than usual for this meeting. One of the scientists tries to persuade the room that it doesn't matter how much data we generate tomorrow, what matters is keeping our overall average below the overall downlink budget. So it's OK if we go over the line tomorrow; we'll make it up on the next day. The rest of the room finally seems to be wising up about this frequently practiced bit of self-delusion, though -- the problem is that they always overspend today, promising to make up for it tomorrow, and somehow tomorrow never comes. The argument doesn't want to go away, until another scientist sardonically calls for a filibuster. "If we talk long enough, it will be too late to put anything in the plan," he says. The rest of them get the message and manage to work together, but the issue clearly isn't laid to rest. After the meeting ends, a couple of pockets of people remain behind, each faction rehearsing its argument for friendly ears.

Since all I have to do is plan the drive, sequencing is relatively easy. I decide to finish before Bob comes in, and to my surprise I succeed -- with a few minutes to socialize, to boot.

And time to eavesdrop, as well. While I'm doing a mindless part of the work, I listen in as a couple of the scientists argue about our general approach to the crater. One of them is pressing Doug Ming's point that we're rushing to the rim, saying that we should be conducting a more gradual, systematic study of the soil and rocks along the way. The other strongly disagrees: "If you were out there, the first thing you'd do is run to the edge of the crater and look in," he says, and that seems to settle it.

Bill Dias has been out for a week or more, and it turns out that he's left the project. More than that, he's left JPL, after 14 years. Nobody seems to know why, or what happened. But he sent email titled "Change is good ...." That change is disconcerting. Bill was cranky, pessimistic and sarcastic (which is probably why we ended up getting along so well -- rim shot, please). He could also be very funny and likable when he wanted to be. I'll miss him.

Shortly before I leave, Jim Bell shows us the latest PANCAM image. It's a picture of the Earth from Mars, taken by Spirit, the one she woke up to take the other night. The Earth is just a tiny dot in the center of the image, a handful of faint pixels -- almost drowned out by the twilight in the unenhanced version. Looking at this picture, I feel an unaccountable mix of pride and something else I can't quite put my finger on -- sadness, I think, or maybe loneliness. Spirit is very far from home, and she will never make it back. Others seem to find the image mostly awe-inspiring. Art compares the picture to the famous Apollo photo of Earthrise as seen from the moon -- "Well," he says, "maybe their picture was better." I think this one is better, because it's ours. But Jim Bell sums it up when he says quietly, "Don't think for one second that there aren't millions of people who would die to be us right now."