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Rocky 7 - Mojave Desert Field ExperimentsExperimenter's Notebook
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The last day of science testing focused on activities near waypoints C and D. The goals of the continued traverse were to conduct as long a traverse towards waypoint D on the alluvial fan as possible and to determine how well the rover stereo cameras could detect the alluvial fan. In addition, Rocky 7's navigation and obstacle avoidance systems would be further tested as the rover crossed the crater field.
In the morning Rocky 7 was placed back at the end point of Tuesday's uncompleted Playa Crater Field traverse, in Mudcrack Crater. The rover acquired a stereo panoramic image and then began moving west toward the alluvial fan bordering Lavic Lake. After about 20 meters of travel Rocky 7 entered the drainage "tail" of a crater. As Rocky 7 traveled up this tail and toward the crater, the walls of the tail became higher and steeper. The rover obstacle avoidance system judged this slope too steep to climb and began turning in order to look for an exit. Unfortunately, steep walls blocked all but two routes out. One of these routes was blocked by a bush, so the only available route out was the path Rocky 7 took while entering this cul-de-sac. After 15 minutes of searching Rocky 7 found a portion of the wall with a slope its obstacle avoidance would accept, and the rover began climbing out of the crater's tail. The wall of the tail was very soft and the rover's wheels dug in deeply. The rover did move up the slope to firmer ground and then continued on its traverse. Rocky 7 covered another 116 m before the Playa Crater Field traverse was ended. The entire traverse covered 174 m.
With only a few hours left in the test, time dictated that Rocky 7 be picked up and moved to within 13 meters of the alluvial fan. A stereo panoramic image was taken and a route up into the alluvial fan plotted. After entering the fan, Rocky 7 acquired color overhead stereo images of the alluvium, collected a soil sample, obtained a PR measurement, and took another color overhead stereo image. Rocky 7 was moved about 1 m back for the final science test of the week. In this test, five of the rover's six wheels were locked in place. The sixth wheel was commanded to rotate, eventually breaking the soil surface and digging into the soil. Before and after images were taken of the soil during this test to help infer soil properties. The day's testing was concluded after this test.