Spirit Sol 685

The weekend drive faulted out right at the start, before even going anywhere. Painfully, it was really a rookie mistake. They fired off a helper sequence, and, as we usually do, put in a check to see if the helper was present, precluding further driving if not. The problem was, they accidentally reversed the sense of the test, precluding driving if the helper was present. Which of course it was, so the drive kicked off the helper sequence and then refused to go anywhere.

I'm just glad it wasn't me.[1]

Partly as a result of this mistake, we're now well below our drive metric. Also contributing to the problem is that they're going to raise the bar. Recognizing that our power has dropped and will continue to drop, we're revising our estimate of when we need to make it to Home Plate. The result will be more driving -- and more pressure on us to get it right.

Not that they seem to be in a terrible hurry. This drive will be all of 15m or so, to a nearby rock target called Algonquin. Where we'll stop to IDD. "But let's have the discipline," SOWG chair Albert Yen cautions, "to spend only one drive sol there." Since we're in restricted sols, that really means spending two drive sols there -- we'll drive only once more this week.

This mistake is the third time in about a week that we've blown all or part of a drive. The first case was when we hit the tilt limit right at the start of an autonav drive, which cut that sol from something like 40m to something like 20m. The second was when we screwed up the time-of-day limit logic, blowing our turn for comm. (At least that one made all of its planned distance, but the mistake is still troubling.) And now this is the third one.

I talk about these mistakes with John and Ashley, to see if we can come up with fundamental underlying reasons. "Complacency" is John's answer, which might be as true as anything. Still, we come up with a couple of new flight rules, which I write automated checks for. Maybe they'll help.

Later, I talk to Frank about how Opportunity is doing. There's good news and bad news, he tells me. The bad news is that we're still not seeing any motion from Opportunity's IDD. The good news is that Joe Melko has identified a failure mode in which a wire cracks, doubling the resistance. And there seems to be some support for this theory in the data. If this were true, we'd be able to resume normal work by just doubling the current through that joint.

If it's true. I can't help getting my hopes up, but I have to remind myself that we still don't know what's wrong, and the IDD could still be lost forever.

I'm hoping not.

[Next post: sol 687, December 8.]


[1] Technically, I'm glad it wasn't I.

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