Starting last Wednesday, the RA team was in town digging the trench I mentioned in the last blog. We didn't quite get down to 20cm, however. The Arm was giving everyone a lot of trouble, by faulting out on an over torque-limit error. The motors that drive the joints are quite large, and when changing directions the torque can get quite large, and thus the failures.

The trench is about a meter square, and the arm takes about a centimeter or so with each tier it digs. Each tier takes about 50 minutes to dig and we did actually get through two tiers with no problems. But each fault took an hour or more to recover from. Actually getting the RA powered back on only took a few minutes, but analyzing the data from each fault and then rewriting the sequence to continue the dig took a lot of time.

A few late nights and several headaches, but we managed to get down over 10 centimeters. The science team will certainly have some interesting pictures to analyze, after all the time we spent prepping the digging area. But I'll tell you more about that over the rest of the week. I'll be working the midnight to 8AM shift.

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