Art's back. He's been on Opportunity for a month or so, so I ask him what's different between the missions. "Opportunity's RPs are more conservative," he says. It's clearly an understatement. "I would think that RPs would like to switch more between vehicles," he adds. I tell him I would. Maybe I'll get a chance, one of these days.
I've come in early for an engineering meeting, which turns out to have been delayed. When it does happen, it turns out I didn't even need to be there. I could have slept in.
But it's interesting, at least. The point of the meeting is to decide where we're going to drive Spirit from here. Or, more precisely, where we're going to drag Spirit from here, since we'll be spending 90% of our time dragging the right front wheel in order to preserve it for when we really need it.
The news that we're going to treat the wheel as already dead -- or, mostly dead -- is unpleasant. Last I heard, things were looking up. But apparently, the mechanical team has decided that there hasn't been enough improvement to declare Spirit's arthritis cured. For now, the plan is to aim for another 2km, and we're assuming Spirit's wheel has only 200m of life left in it, which is why we'll need to drag it 90% of the time. Still, this assessment is generally felt to be ultra-conservative. There's still hope the problem will fix itself -- say, while we're parked for the winter.
To help us during our gimpy drives, we have a new tool, a solar picture. This shows where solar energy is highest, helping us pick out good destinations for the rover. Ideally, we'll end every sol's drive in a spot where we'll collect the maximum solar energy -- which we need; we're so desperate for energy that we can't afford to use the IDD at all thisol, even though we're sitting on interesting rocks. With a kind of cheerful irony in his voice, Matt Golombek laments, "We drove 190 sols to get to outcrop. Now we have outcrop under our wheels and can't do anything with it even if we wanted to."
The meeting keeps getting in John Wright's way. He's trying to be polite, but he just wants to get started sequencing already, and he evidently sees the meeting as a needless delay. When Julie asks if we have a plan for where we're driving, John testily replies, "Yes: I'm going to ignore all recommendations and do it my way."
Well, John -- I think to myself -- you wanted the RP-1 job. This is what it's like.
Julie Townsend keeps getting empty envelopes in her JPL mail. Maybe it's a stalker -- it could be the snail-mail equivalent of calling a girl, breathing heavily, and hanging up. But I take another tack, and suggest she contemplate the empty envelopes as a Zen experience.
The drive is a weird one. For one thing, we drive backward the whole way. For each meter we drive, we turn off Spirit's lame wheel, drive 90% of the way (90cm), then re-enable the wheel and drive the remaining 10% (10cm). Since five-wheel driving causes the rover to yaw, we also have some fancy tricks to fix our heading periodically. It's slow, and the sequencing is complex, but I soon pick up on the patterns and it's not so bad.
Just before the CAM, Julie plays a new Public Service Announcement she found on NASA's Web site. It's a "Stay in School" video featuring Aerosmith. It also features fleeting glimpses of a bunch of MER team members, such as Justin Maki.
In honor of Art's return to the Spirit world, Julie also plays a video in which Art features prominently -- the "Trek to Bonneville" video from the MER home page. We watch through it and cheer good-naturedly for Art when he appears. To my surprise -- I never watched this one before -- I'm in it too. Very briefly, at the end, they have some B-roll of me driving the rover, the stuff the JPL media guy came and filmed months ago so that they'd have B-roll for stuff like this. I'm not saying anything, they're just shooting over my shoulder for two or three seconds as I play around with RSVP. But still --
Courtesy NASA/JPL-Caltech. We don't seem to have publicly released many images of our "lily pad" maps. This isn't exactly what we were using, but it's close enough: a color-coded map, overlaid on actual imagery, showing areas where we'd expect better (blue) or worse (red) solar energy.
Courtesy NASA/JPL-Caltech. The "Trek to Bonneville" video. The image above links to the MP4 video; it's also available in other formats.