Opportunity Sol 321 (Spirit Sol 341)

I'm back upstairs in the Land of Opportunity. Looks like an easy one: MIing the solar panels (using a canned sequence) and then a 60m drive, mostly straight, toward the heatshield.

Quite a relief, I must admit, to be away from the depotatoization stress over in the Spirit World. When I see Jeng and he asks if I'm on Spirit thisol, I tell him I'm on Opportunity and what we're up to. "Man," he says, shaking his head, "you're always in the middle of the action." Yeah, but this potato thing is something I could stand not to be in the middle of.

On the upside, there's a rumor that we've been named Time's Person of the Year. Other happy news: the ITAR issue is dead, Jim Erickson announces.

The ITAR issue was a concern about the upcoming imaging of the heatshield. ITAR stands for "International Trafficking in Arms Regulations," the set of USA laws covering -- well, what it says. See, since the heatshield is part of a re-entry vehicle, there was some worry that releasing images of it would be tantamount to releasing information about weapons systems. Which is not as crazy as you might think: for good reasons, all spacecraft are legally classified as weapons systems, so we have to be careful about all information we release, same as if they were ICBMs. (Because they easily could be: replace Opportunity with a nuke and change the launch trajectory a hair, and it's goodbye, Luxembourg. Or something like that.) There was also some concern that we'd be unlawfully releasing proprietary information held by Lockheed Martin, who built the reentry system, but that was secondary to the ITAR worries.

Naturally, Jim didn't want his entire uplink team jailed for putting pictures on the Web, so he had the legal department look into it. And in a gratifyingly sensible decision, the legal department told us to take all the pictures we wanted and hand them out like candy canes.

Somehow I decide this would be a good day to experiment with ratcheting down the HAZCAMs to half-a-bit-per-pixel compression. I've been on this kick, off and on, for weeks; it would save us a megabit each drive sol, which we could spend on science or on more important engineering data. The image just has to be good enough to tell us two things: (a) did we move as expected during the final step of the drive (usually the last meter or half-meter), and (b) is there anything blocking deployment of the IDD? A half-bit-per-pixel image should do this just fine, and anything that gets us more science return is worth considering.

Or so you'd think. But I can't get either Frank or Justin -- and Justin's a scientist, damn it -- to get very excited about this. I do manage to talk them into trying, despite themselves, so thisol's our first experiment with it. At the very end of the drive, we'll take a one-bit-per-pixel image -- as already planned -- and then take the reduced-quality image, so that we can compare them on the ground. If the reduced-quality image is good enough, I can start working this into the daily plans, which should get the ball rolling.

Since both the IDD and drive are already mostly sequenced, it's a relatively light sol. I do however, manage to create some work for myself: I redo the drive to spin the rover around and drive backward, following recent guidelines capturing lessons we learned from Spirit's long-standing (and recently solved!) wheel problem.

I am actually somewhat worried about this drive. I think I'm exhausted from the week. There's a lot I should have thought of. I should have made the drive more robust against failure. I should have quadruple-checked my math -- how long has it been since I did the trig I needed for this sequence?

Oh, yeah, and the rumor was false: we're not Time's Person of the Year, after all. Funny, if I hadn't heard the rumor, I never would have cared either way. But now, all I can think is: those bastards!

[Next post: sol 344 (Opportunity sol 324), December 21.]

Courtesy NASA/JPL-Caltech. In the distance, Opportunity's heat shield glints in the sun.

1 comment:

David Noble said...

I'm glad the legal decision went that way... the heat shield image is one of my favorites!

It also reminds me of the time there was a big fuss about trying to pull back the image of the Coumbia memorial plaque because it got into the pipeline before the deceased's families had been informed. Note to the conspiracy theorists: MER didn't even have a procedure in place for suppressing images (at least shortly after landing); they were on an automated pipeline out to the public. It caused problems when the project tried to delay release of an image for even a little while.