Opportunity marked its 180th sol on Mars without pausing to celebrate. Originally slated for missions of 90 sols each, both Spirit and Opportunity have passed the double-mission milestone and are continuing their phenomenal journeys of discovery.
On sol 177 Opportunity performed a two-hour rock abrasion tool grind on the target "Diamond Jenness," then took the resulting hole's picture with the microscopic imager. Surface debris and the bumpy shape of the rock apparently contributed to a shallow and irregular hole, only about
2 millimeters or .08 inches deep, not enough to take out all the bumps and leave a neat hole with a smooth floor. The alpha particle X-ray spectrometer examined the rock's composition in the abraded area during early morning of sol 178.The team decided that sol 178 would be used to grind into "Diamond Jenness" again in hopes of deepening the hole. The sequence went extremely well with the rock abrasion tool grinding almost an additional
5 millimeters (about 0.2 inches). The rover then started a M�ssbauer spectrometer reading of the deepened hole.On sol 179 the rover completed the M�ssbauer integration, gathered some remote-sensing data, then positioned the alpha particle X-ray spectrometer on the abraded hole for an early-morning integration at cold temperature on sol 180. This double integration of the hole (once on sol 178 at an intermediate depth and then a second one at full depth) will give the science team a unique opportunity to evaluate how the composition changes with depth.
On sol 180, which ended on July 27, the rover stowed its arm and drove back up the slope about 1.5 meters (about 5 feet), then turned a little to the right to go back down about 0.5 meters (about 1.6 feet). The drive up was to gain a vantage point from which to image the abraded hole in "Diamond Jenness" with the panoramic camera and to evaluate characteristics of the driving on this particular terrain. The drive back down and to the right served to position the rover for potentially proceeding farther into the crater (avoiding a sandy patch to its left). It also left the rover at a better angle for communications in the afternoon. The drive went well, with less slip that anticipated, reinforcing the team's confidence in driving back up out of the crater on some future sol.
In general, the rover continues to perform well, benefiting from a predominantly northward tilt and the greater solar-array energy that affords. The Mars Odyssey orbiter continues to perform as the rover's primary source of data return. The location on the slope of "Endurance Crater" and intensive use of the instrument arm hinder rover drivers from orienting Opportunity optimally for the radio relays to Odyssey. The level of communication is acceptable for now and the team expects that, some sol, Opportunity will venture back out of the crater to explore to new places. When the rover is on flatter ground, the team can optimize communications with Odyssey more often.