2010-04-12

Spirit Sol 453

On my way in I notice we're on the front page. Our funding was extended for 18 more months, making the front page of the Pasadena Star-News. I remember when I'd come in and we were front-page news every day. I buy a copy for nostalgia's sake.

I'm in an hour early, to get a jump on the drive sequence, but Jim Erickson needs a minute of my time. "Did you hear about the problems over the weekend?" he asks. Oh, dear.

Both rovers had bad weekends. Opportunity's drive faulted out before it even drove anywhere. Last week the suspension limits tripped during a drive, and tripped again during the auto-recovery -- an off-nominal circumstance, but one we plan for. For the weekend, they sequenced a drive where they backed off the ripple they tripped on, then continued, ignoring the suspension limits during the backoff. But they didn't explicitly disable the limits, they just assumed the limits were i the "ignored" state for the first part of the drive. However, it turns out that the flag that tells the rover to check the suspension limits (not ignore them) was accidentally saved to EEPROM as the default weeks ago, so Opportunity actually applied the most recently set suspension limits, and since they'd tripped before, and Opportunity hadn't moved, it went right ahead and tripped them again. This was a problem that was just waiting to bite us. And then, possibly because of that error, they mis-timed the solar-array stomp, which meant the rover didn't nap when it was supposed to, and thus is power-poor.

Spirit had problems, too. They didn't properly clean up after last Thursday's fatal. (Which fatal, you will recall, was my damn fault.) The fatal caused Spirit to decide it didn't know where its HGA was pointed, so it didn't listen for the uplink from Earth. As a result, none of our cleanup sequences made it up over the weekend. Which means we can't drive today; we still need to do our imaging and update the rover's position. Lucky for us, Beth Dewell noticed the problem and already got Spirit back into decent shape over the weekend, which is a good thing -- else we'd be down for another day.

So, for those of you keeping score at home: last time I was on Spirit, I jammed a potato in the wheel, which blew about ten or twenty sols. This time I fataled it and blew Thursday through today (Monday) at least. The Opportunity problem is not my fault, but I couldn't feel worse if it were. I am a bad rover driver. I'm glum. I want to kill myself.

But if we're not driving today, I have time to answer Jim's questions, at least. He ticks them off. "These problems we've been having with the vehicles lately: are they problems due to unfamiliarity with the new version of the flight software? Are the RPs overworked? Are they complacent?"

I answer these as best I can. I know some of the problems were due to unfamiliarity with the new flight software; it's a partial explanation. I don't think the RPs are generally overworked. (I personally have a lot more work than I have time for, but this afternoon I'm going to talk to someone about coming in to the RSVP development team to pick some of it up, which will mitigate the problem.)

As for complacency ... well, I want to say no, but the honest answer is probably yes. We're not as paranoid about these vehicles as we used to be. Some of that's understandable and even proper. Some of it, maybe not.

Jim nods thoughtfully and goes away. As if on cue, Frank enters, fresh from the Land of Opportunity. He tells me he wouldn't have caught the problem that led to a fatal, either, but: "I was gonna give you a ribbing about it anyway, but then we had our problem over the weekend, and now I can't give you a hard time."

"The universe smiles on Scott," Al Herrera remarks.

If he's right, it means the problem on Opportunity was my fault. You know when I said I couldn't feel worse? I might have been wrong.

Upstairs, while we're waiting for the SOWG meeting to start, we try to look on the bright side of this extended anomaly. "The batteries will be topped off," Chris points out.

"And now the bar is lowered," I add. "If we can just manage to drive without fataling, we'll be so happy." It's black humor, but it's humor.

Squyres is -- what's the equivalent of "visibly unhappy" for a disembodied voice, "audibly unhappy?" Well, he's unhappy. We've got basically nothing to show for last week, with the ODY problem followed by the fatal, and today will be basically spent on recovery. He pokes at this to see if we can drive anyway, but we really can't do it without more data. He manages to talk Callas into allowing a MTES checkout, so I suppose that's something, from his point of view.

But we're 120 sols into the climb and only halfway up the hill, and we're 50 sols away from our deadline. We're power-rich right now, but in about 50 more sols, the sun's wandering position in the sky starts to favor south-facing slopes over north-facing slopes such as the one we're on. Our friendly, solar-panel-cleaning dust devils might have extended the deadline, but we'll eventually have to cross to the far slope or die. Steve wants to go, go, go, and we've got to just sit here. At least for today.

"We're gonna have a good week," Steve says emphatically at the close of the meeting. "Power of positive thinking."

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