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Rocky 7 - Mojave Desert Field ExperimentsExperimenter's Notebook
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The main goal for Tuesday's field test was to complete an initial 65 m traverse. This short traverse allowed a thorough check of Rocky 7's systems, allowing any problems to be addressed before the long 250 m traverse on Wednesday. Rocky 7's close-up imaging system was tested as the rover examined two rock samples chosen by the Science Team. The rover's manipulator arm was also used. The arm and its digging scoop allowed Rocky 7 to excavate soil samples to a depth of approximately 5 cm.
Rocky 7's traverse started approximately 70 m northwest of the large craters (Spa and Tadpole) in the area. The Science Team had placed two science targets (i.e., rocks) near Tadpole Crater. The rover took a panoramic image in order to determine waypoints along its path to these targets. Rocky 7 then started its traverse, traveling southeast toward Tadpole Crater. Along the way, a panorama was taken back the way the rover had traveled. It was hoped that the stereo cameras would be able to resolve the tracks left by Rocky 7's wheels. In some instances, the cameras could. Other areas of the playa, however, were too hard for the rover to leave wheel tracks.
Unfortunately, software problems during this traverse caused Rocky 7 to reboot its computer systems periodically, a time consuming process. In order to conserve time and give the engineers longer time to solve this problem, Tuesday's traverse was cut short. As a result, Rocky 7 was physically placed nearer to its science targets after approximately 18 m of travel. The rover covered the 5 m separating it from its first target easily. After taking a navigation image of the rock, the Science Team designated two points on the rock target for close-up imaging. Rocky 7 then deployed the close-up imager on its mast and obtained several images of these target points. Before stowing the mast, the rover obtained an image of the rock from overhead.
Since both teams wanted to quickly test the mast and close-up imaging system again, Rocky 7 was physically moved to another science target (a rock). There, another close-up image of a target point on the rock was successfully obtained.
With the mast imaging tests complete (both panoramic and close-up), the only test remaining to be completed for the day was the manipulator arm sampling test. Rocky 7 was carried to a point approximately 0.5 m from the edge of Spa Crater, where the test could be conducted on the crater's soft ejecta blanket rather than on the hard, dried playa surface. Eliminating the traverses to the second science target rock and to Spa Crater, which were not stated goals for Tuesday, gave the Engineering Team greater time to solve the software problems in preparation for Wednesday's prime goal, a 250 m traverse.
After several attempts, a soil sample was eventually excavated successfully. Command was then transferred to JPL, where Diana Blaney repeated the command sequence for the manipulator arm. Rocky 7 again successfully completed the dig, and command was transferred back to the on-site team.
Before calling an end to the day's testing, the mast's stereo cameras were used to perform a self-inspection of the rover. The flexibility of the mast allows nearly every portion of the rover to be imaged. This will be a valuable tool during the Mars mission as it will allow ground engineers to perform visual inspections of the rover's condition. After these inspection images were acquired, control of Rocky 7 was turned over to the Engineering Team. The team spent the rest of Tuesday diagnosing and correcting the software problem which caused the Rocky 7 to reboot repeatedly. The Engineering Team continued its work even after the sun set, using a flashlight shining on the rover's sun sensor as a new artificial navigational fix.