Spirit Sol 81

Once again, I devote my day to the updated RoSE delivery, implementing the remaining requested feature and packaging a new test release. So much for that.

The extended mission may be extended further than I had thought. All of a sudden, people are talking about Spirit lasting 270 sols (150 for Opportunity). As of Monday -- only a few days from now -- we're on Earth time, and the Earth-time schedule starts at 7AM. I can't do six months of 7AM, but Chris and John will likely take mornings, and I'll take afternoons. Happily, this doesn't mean I'll be RP-2 all the time, because our days will shift in such a way that, after a while, the afternoon shift is doing the first half of the plan, and the next day's morning shift finishes that plan. So the humans will stay on the same schedule and let Mars rotate around us, rather than vice versa.

Once again, the downlink assessment meeting reveals that our Mazatzal exploration schedule has been pushed back slightly; RATting takes a lot of energy, and we'll need sol 82 to charge the batteries. Now the drive starts on sol 85. True to form, the software update has been delayed again as well; it now starts on sol 96. Xeno would be so proud.

They revisit the question of how far to traverse the crater before heading for the hills. The tradeoff is that we'll get less 3-D data on the crater (we won't ever see the parts of it that were initially hidden by the rim itself) vs. getting to the hills that much sooner. The sooner we start the long-haul drive, Ray points out, the more energy we have to drive with; and we might as well start driving while the rover is completely healthy.

"How far around the rim would we have to go to make staying here worthwhile? A hundred meters?" Ray asks. "Less than a hundred meters," Larry Crumpler answers. "Ninety-nine meters?" "Ninety-nine meters, yeah," says Larry.

"So how many people just want to get the hell out of here?" Ray asks. When he rephrases it a little more neutrally, the vote overwhelmingly favors driving to the hills early.

Props to Long John Silver's. Their free-shrimp deal was contingent on our announcing an ocean of a certain size (5 million square km, I think), and we had to announce it by 29 Feb. We announced a smaller sea, and didn't do it in time. But they're giving away the free shrimp anyhow. Yeah, I know it was just a promotion and they were leveraging our fame and whatever. But on the other hand: free shrimp.

I'm just about to leave, but I realize that if I stick around for ten more minutes, I'll be able to be in the meeting with Dr. Elachi, who's going to tag up with us this morning. So I grab a sandwich at the cafeteria and show up for the meeting. As I expected, this turns out to have a bunch of interesting moments.

Mission managers for both spacecraft sum up their progress so far, and the state of each rover. When Matt Wallace says that Opportunity just had their best data pass so far, 104.3 Mbits, Mark Adler jokes, "Spirit's done 108 -- not that we're competing or anything."

Matt also reels off a list of spacecraft subsystems; each one is green, green, green -- until he gets to the Ice Cream subsystem. That one's yellow -- the freezer is starting to get a little low.

And Matt sketches their plan for Deep Sleep. This is their effort to sidestep the problem of the stuck-open heater switch that's costing Opportunity so much energy. Deep Sleep means powering off the bus, and relying on the sun to wake up the rover (when enough energy starts to flow through the solar panels, the rover turns on automatically). They give up a lot for this: they can't do overnight comm passes or science observations. But they also can't heat at night, so the rover will get colder than they'd like. Eventually, around sol 150, it will get so cold that they'll probably lose the MTES. Moreover, it's just a scary strategy. One day they'll turn the rover off and it won't come back on, and somebody will have a bad day.

Justin Maki points out that between the two rovers, we landed 20 cameras on Mars (if you count the descent imagers, which are not on the rovers themselves) -- more than the total number of cameras that had been landed on Mars up to that point.

The crater Opportunity is going to drive to next is called Endurance Crater -- I guess the "Endurance" proponents from early in the mission got their way at last. It's 700 to 800m away, and they expect to cover the distance in about 30 sols, including stops for science along the way. They are really going to be booking.

Elachi tells us we're popular. He was talking to an NBC Dateline producer who told him a story: every morning, the producer's five-year-old daughter wakes him up and asks, "What did the rovers do last night?" They check it out on the Web site every day before he leaves for work.

We have also "had a major impact on the budget," as he phrases it. The Mars program funding is currently $600M/year. That's going up to $1.2B/year in a few years (for perspective, that's more money than JPL got in a year, total, when I started working here). Mars exploration is going to be huge.

So is the moon. We're also kicking off a Lunar Robotic Exploration program, sending a rover every year or two.[1] They'll also be sending landers, but some other center (or maybe LMA) is going to do that (though we'll still have a hand in those missions, supplying scientific instruments for them). We'll be doing the rovers. "Whenever you're finished here, you'll have lots of opportunities on the Lab and in the Mars program," he says. Not bad, considering that -- as I had heard rumored before -- at one point we were this close to NASA HQ canceling one of the two rovers. (This was when we needed extra money for the flight software. Their idea was to cancel the second rover and use the cost savings to fund FSW instead. To their credit, HQ decided to come through with the money, and the result was a rover in Meridiani -- the one that found the water. Another lesson learned from that: they're now thinking about doing two rovers, not just one, for MSL.[2])

Bob Deen asks whether we'll be flying a MER-C and MER-D -- two more MER rovers. No, says Elachi, but we have looked into reusing some of the technology for the lunar rover missions. It occurs to me that they could also reuse the acronyms: Moon Exploration Rovers, here we come.

Elachi says we've raised the bar for other missions, including Cassini. We had "six minutes of terror"; Cassini will have "an hour and a half of agony."[3]

Elachi downplays reorganization fears. From 2000 to 2010, JPL will be launching more missions than it did in all of JPL's 40 years before that, he says, and it's appropriate to look at whether we need a reorganization to handle that. We won't be splitting groups or sections but may move the sections around at a division level.

Somebody asks what mission success criteria we haven't met yet. We just need to put a few more meters on the wheels and hang in for a few more sols. "We do have things we need to do for NASA," Elachi says. "But I can tell you that in the eyes of the world, you have already achieved full success."


[1] We are? What the hell happened to that plan? That would be awesome! I want my flying car and my goddamned moon robot, already.

[2] Grr. Don't get me started.

[3] During SOI, their Saturn Orbit Insertion.

1 comment:

James Canvin said...

One of my most vivid memories of the whole MER story is when I first heard that Spirit could last to sol 270. I was astounded that that was considered possible (and thrilled that there would be so many more sols to enjoy than I was expecting :) ).

If anyone had told me back then I'd still be following BOTH rovers 5, FIVE! years later I'd probably have died of shock.