2009-01-07

Spirit Sol 5

Spirit's landing place is now officially "Columbia Memorial Station."

I've been too wired to sleep. I got maybe three hours of sleep last -- uh -- night. Or day. I'd say that joke is wearing thin, except that it's no joke. Fortunately, this problem is self-regulating. We'll see whether it starts regulating itself before or after I need to drive the rover.

I arrived at 23:30 for a science meeting that, as it happens, had been postponed until 01:30. So I had some time to kill. I spent it looking over some RSVP features I'm not that familiar with; Frank [Hartman] explained some bits that had confused me previously. I feel better about all that now.

The PANCAM PUL[1], Jim Bell, had had T-shirts printed up with the PANCAM logo, and I'd ordered a couple, so I headed to the PANCAM room to pick up my T-shirts, as I'd been meaning to get around to doing for days. (How many days? I don't know any more. My time sense is distorted.) But before I could ask him for the shirts, I got distracted by the enormous PANCAM postcard printout they'd put up on the wall. The term "postcard" is a statement of its role in the mission, not its size -- this printout must have covered a square meter (12 megapixels, baby, and we're just getting warmed up). It's beautiful. Rocks are neat, and I like it that I can now pick up on basic stuff like wind tails without having them pointed out to me. I got so engrossed in discussing the image with Charles Budney that when Jim saw me and offered to get the T-shirts for me, I almost told him not to worry about it!




Courtesy NASA/JPL-Caltech. First color image from Spirit's PANCAM.



As I left, I heard they'd started receiving image data from the Odyssey pass[2]. Heading to the SMSA, I got distracted again, this time by a huge, fantastic image of Gusev crater assembled by someone at ASU[3]. Objectively the resolution is not that great, I guess -- at 18m-per-pixel resolution, you could maybe see a Martian school bus -- but the image seemed pretty sharp to me. We figured out which craters were the ones we'd seen in the descent images, and more or less located our landing spot.

I made it to the SMSA at last, only to be blown away a third time. Justin Maki had just put up a couple of new stereo anaglyphs (the 3-D images you need to wear the funky blue-and-red glasses for). I grabbed a handy pair of 3-D specs and got lost on Mars for a while.

Lesson for today: I am easily distracted by pretty pictures.

Rick Welch was selling 3-D glasses -- not the cheap cardboard ones, cheap plastic ones. For five bucks. I bought a pair just so I'd be sure to have one handy at all times, thinking even as I did so that this was going to be a waste of five bucks: the cardboard ones are all over the place, heaps of them, and I know perfectly well that I won't carry the plastic ones around because they're bulky and I'll break or lose them. But Rick had sold the whole boxful within minutes, so at least I'm not the only one wasting money. I'm not sure whether that makes me feel better or worse. This does prove once again that Rick is smarter than the rest of us, though.

(Kevin Burke pointed in turn at me in my plastic glasses and then at three other people who were wearing the cardboard glasses, saying, "Stylish. Geek, geek, geek.")

The images are showing us a more rolling terrain than we thought, but nothing that looks like a genuine driving hazard. We're not sure what the rover will make of the terrain, though -- will it interpret the dips and rises as impassable hazards? Will we need to make it smarter? We've got the data and the software to find out now, so we should know soon; there's a software patch ready that will help the rover through this terrain if we need it. What's really great about these images, though, is that we're getting good stereo data out to a hundred meters, maybe farther -- the ridges in the distance retain their 3-D shape. This is incredible stuff, beyond our wildest dreams.

I knew Frank was in another room, getting frustrated with some software problem, so I went and told him about the new images, and we headed back to the SMSA together. ("Thanks," he said later, "I needed that.") I broke my own rule about not using the camera flash when people are trying to work, snapping a couple of pictures of people wearing their 3-D glasses.




The fancy-schmancy 3-D glasses Rick Welch sold me for five bucks.



Other engineers marvel at our recently arrived 3-D images.



Fixating on the 3-D images had made me late for the science meeting I was waiting for, so I headed over there and tried to find an out-of-the-way corner.

I sensed immediately that the mood in the science room was more subdued. Fatigue, already. People are starting to go from tired-but-happy to happy-but-tired, and their mood is going to get worse before it gets better. And a lot of them still don't have anything to do. Those scientists whose instruments live on the rover's arm don't get fully involved until the rover is off the lander and deploys the arm, and that's not for days yet. And then Ray Arvidson and Mark Adler have to give them bad news: egress is going to be delayed another sol, because the airbags didn't retract as far as we'd hoped. So it'll be that much longer before a lot of the scientists get their turn.

But everyone is working the weird hours anyway, and not sleeping. For now, we're still jazzed enough that people aren't snapping at each other, but I can't help wondering how much longer that can last. (Incidentally, the new delay disappoints me a little, too. The original plan would have had me doing the first real drive of Spirit -- on my birthday. When egress slipped one sol, I didn't worry too much; things were going so well generally that I thought we might win that sol back somehow. But two sols of slip means that the chance is gone for sure. Oh, well. I'll still have the one-of-a-kind birthday present, I'll just get it a couple of days late.)

In the meeting, they were showing the same anaglyph that was displayed in the SMSA, zoomed to cover two big projection screens, a total resolution of something like 3200x1200 (and that still wasn't the full image). It's the IMAX version of Mars. Naturally, I instantly whipped out the five-dollar glasses, thinking smugly, "Who's the smart one now, Rick?" (Still not me, as it happens; there are meter-tall mounds of the cheap cardboard glasses in the science areas, too. I knew that, I was just steadfastly ignoring it.) PANCAM already has more than half of the mission success panorama generated and stored on the rover, though much of that is still awaiting downlink.

They've got Mini-TES data now. The Mini-TES guy said, "We have a working spectrometer on the surface of Mars," which as you can imagine was an applause line. This is particularly impressive in their case because Mini-TES didn't have an engineering model -- that is, a version of the instrument they could test on the ground. As he said, they've only just now "taken it out of the box" and started playing around with it, "so don't expect too much from us yet."

Too modest: they already have some scientifically useful results, showing that the spectrum taken from the ground largely confirms the one observed by the TES instrument on board the MGS orbiter. The plot they put up dramatically confirmed the orbital data, showing a significant difference only in the CO2 levels (the Mini-TES saw a lot of CO2 where the orbiter saw none; I didn't understand the reason for the difference, but they said it was expected). Better yet, both the orbiting TES and the rover-based Mini-TES show trace amounts of water bound into the soil near the surface. In the case of the Mini-TES, this is especially exciting because it means there's water right under the rover's feet, as it were. There was some question about whether this means they can claim to have found liquid water. Consensus: no. But to me, it seems it's so close we can taste it.

The PANCAM seems to be giving the other science teams an inferiority complex. As he finished, the Mini-TES guy apologetically ("It's not as good as Jim's stuff") showed a very-low-resolution infrared image of the rover's neighborhood. And when I say low-resolution, I mean low-resolution. Imagine that gorgeous PANCAM pan, but in black and white, as seen by Mr. Magoo. But it's good stuff all the same: it proves that the instrument is working, and working splendidly, measuring temperatures to within a tenth of a degree. They won't show it on the news tonight, but it's strong science.

There's a lot of support among the scientists for a long drive. The distant hills are 1km to 2km away, probably at the high end of that. We're all ambitious: drive to the hills? To heck with that! Drive to the top of the hills![4] We rover drivers used to worry that the scientists would never want to leave the spot we landed in; we were prepared to argue for driving (never mind that a total 1km traverse is required for full mission success; sometimes the scientists can get what they want anyway). But they're doing the arguing for us.

If we're going to drive to the hills, we'll want good imaging data taken from here, so we can make good decisions about how to plan our route and stuff like that. This means taking some high-resolution, minimally compressed PANCAM images of the destination, probably a full horizon pan. No technical problems there, but it does mean changing our impact-to-egress plan, which will make mission management nervous, so the scientists talk proleptically ("prolepsize"?) about whether and why to do this and how we should sell it to management. ("What do you need from us?" someone asks Jim Bell. "We don't know yet -- we haven't had the meeting with the mission managers, so we don't know what they want." "What's your favorite beer?" "No, what's their favorite beer?")

Gusev[5] must have been a lake. So why doesn't it look like a lake up close? It doesn't have the right kind of rocks, for instance. Arvidson asks people for their hypotheses, which have already been flying around JPL's email system, and people start tossing out ideas. The hypothesis I understood best was a pretty simple one (it has to be or I wouldn't understand it :-): Gusev was indeed a lake, but the rocks we're looking at are the remains of boulders washed in from elsewhere by rivers, possibly in spectacular flood events, probably late in the lake's life. Possibly in part to help the MI[6] PULs feel included (they're one of the teams that can't do their real work yet), Arvidson speculates that the MI will help resolve these issues, since it will show us a lot about the texture of the rock.

There are more ideas than evidence at this point, and before the meeting ends Arvidson makes a brief statement about that: "This is how science is done -- you put out crazy ideas, knock some off the table, as new data comes in you have new ideas, and if you're lucky you wind up with the truth." I knew this already, I knew it in my bones, but it reminds me that people would find science more appealing if they knew how haphazard its progress can be. At least Arvidson gets it, and the people in the room get it, working scientists all. It's a great place to be.

I spend the rest of the night stupidly damaging my wrists with piddly, unnecessary coding. Making my new LST[7] clock configurable. Writing a Perl script to turn Andy Mishkin's schedule spreadsheet into a set of simple text files, one per rover driver, so that we can tell when the heck we're supposed to be here and when we're not. (I send the output to the other rover drivers and receive due kudos, which I'm sure will comfort me greatly when I get carpal tunnel syndrome and can't work any more. I do it to myself.)

Along about 09:00, I start telling myself that I should get out of here before I get dragged into a meeting. Too slow. The meeting finds me, and I end up in one for more than two and a half hours before I can leave. At least this isn't one of those cases where I got sucked in just because I didn't say no when I should have: it's an important discussion about how to ensure that our software accurately models the state of the rover, so that we don't inadvertently send inappropriate commands that damage it. Some bugs were just discovered in our mechanism for doing this, and we need to work out a software fix we can try to sell to management, and a manual procedure for working around the problems if management says no (as they surely will). Better go buy some of their favorite beer.



Footnotes:

[1] Payload Uplink Lead. He's in charge of the instrument today (and Jim Bell, in particular, is the top guy on the PANCAM team).

[2] That is, data sent back from the rover by a relay through the Odyssey spacecraft in orbit around Mars.

[3] Arizona State University.

[4] At the time, nobody took this seriously. We knew it was just our own euphoria talking -- because we all knew those hills were impossibly far away (and it turned out they were a bit farther away than we then thought, at that). Later, of course, we did it.

[5] Gusev Crater, the enormous crater Spirit landed in. Gusev Crater looks, from orbit, like a Mickey Mouse-head balloon -- the "string" of the balloon is, we think, the bed of the river that fed a lake in Gusev Crater.

[6] Microscopic Imager, one of the instruments on the rover's arm.

[7] Local Solar Time. It's a Mars clock.

1 comment:

Jean-Louis said...

Lovely written blog Scott! Well done :-) It is great that you are sharing these augmented notes of your with us. As a MER follower myself, I can't tell you how exciting this all is (even if it's from 5 years ago).

Kind regards,