Opportunity Sol 518 (Spirit Sol 539)

Somewhat to my surprise, the drive executed quite well. We made the whole 15m, right along the intended path, so we're just continuing along the Blue Line today.

The drive even went faster than we'd thought, executing in only an hour and a half, as opposed to the two and a half we expected. But it turns out this is due to unintentional cheating. When we used to charge along the plains, we used step-skipping -- if autonav saw a sufficiently benign path, the rover could take a couple of extra steps without updating its world map. We don't want to be doing that now, but we forgot to turn it off, so the rover didn't pay as close attention to the drive as it was supposed to. That's why it went faster. Unfortunately, we'll have to turn off step-skipping as of thisol.

We also continue to face a data-products crunch. The problem right now is not the amount of data on the rover, but the number of files, a separate limit. The kind of driving we've been doing generates huge numbers of data products, and our downlink has been fairly poor, so today we have a choice to make. We can either cut back the verbosity of the drive data -- undesirable, because then if something goes wrong, we may lack the data to diagnose it; or delete yestersol's output without downlinking it -- but then we won't know why visodom didn't converge in some cases where we expected it to; or not drive -- but nobody wants that; or find a bunch of other stuff we can delete. They go with the last one.

Thisol brings a revision to the Rules of the Road. In short, they're relaxing. We can now accept 40% slip, rather than the 25% that had been the previous rule (or the 30% we'd actually been targeting). And tilt limits and max drive distances are no longer explicitly specified in most cases; we're now supposed to use "appropriate" figures. This is good and bad -- on the one hand, it means the RPs will take more of the heat if we make a poor choice. But on the upside, we get to make the choices, which is how I think it should be. And it's a reflection of our overall excellent performance since egressing Purgatory. So, hell, you look at it the right way, it's a compliment. Can't complain about that.

[Next post: sol 542 (Opportunity sol 521), July 12.]

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