Spirit Sol 871

We're continuing the extended RAT-brush campaign on Progress, but it hasn't been going well. For one thing, the RAT stalled again, possibly due to a pebble getting jammed in the works.

At first there's talk of blowing off the IDD work for the sol and just doing remote sensing, but cooler heads prevail. We end up doing an MI of the RAT hole, as much for engineering diagnostics as for science reasons -- if there's a pebble, we want to spot it. Then we'll image the RAT with the PCAM and FHAZ, so that if the putative pebble's lodged in the machinery, we'll have a shot at spotting it.

All in all, reasonably routine. The one thing that makes me nervous about this sequence is how close we're getting to the soil. As the RAT hole gets deeper and deeper, we move the MI in closer and closer. But since the MI mosaic that images the RAT hole also moves the MI over portions of the soil outside the RAT hole, we get closer and closer to the soil there as we go.

Our minimum standoff is normally about 17mm, but thisol it's going to be 9.5mm. Later we get updated numbers and find that it's not quite as bad as that, but it's close, at 9.85mm. That's within our 1cm error budget for the instrument positioning system, and I can't help disliking it. If you'd worked with Angry Bob[1], you wouldn't care for this, either. Imaging from the last time, when we were only about 1.5mm higher, shows that we should have acceptable clearance, so ... well ... it's one thing to be nervous, it's another to be unreasonable. I shrug and send the commands.


[1] The nickname for original rover driver Bob Bonitz. If you're curious, here's the tale of his nickname (see that post's footnote).

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