Mars Rock “Arnold Ziffel” Gets Close Examination by Opportunity

SPIRIT UPDATE: Spirit Investigates “Wooly Patch” – sol 194-197, July 26, 2004

On sol 194, Spirit took a large microscopic imager mosaic, consisting of 34 images at multiple positions, of a target called “Sabre” on an outcrop rock called “Wooly Patch.” This was followed by a two-hour reading by the Mössbauer spectrometer and an overnight, seven-hour reading by the alpha particle X-ray spectrometer.

On sol 195, the rock abrasion tool dug a surprisingly deep hole in only two hours of grinding. The rock appears to be softer than what scientists and engineers have seen previously in Gusev Crater. The alpha particle X-ray spectrometer was placed in the rock abrasion tool hole at Sabre. However, due to uncertainties in how long the arm and grinding operations take, the sequence was terminated a few minutes too early and a planned overnight alpha particle X-ray spectrometer integration did not take place.

Spirit recovered the alpha particle X-ray spectrometer integration in the sol 196 plan. The sol began with a microscopic imager mosaic of the rock abrasion tool hole. The alpha particle X-ray spectrometer was put back in position in the hole, and reading lasting more than six hours was successfully performed, starting at about 4 a.m. Gusev time on sol 197.

The work on Sabre was completed with a very long, 21-hour Mössbauer integration, which was expected to be completed the morning of sol 198 (July 24). Before the integration was started on sol 197, a microscopic imager mosaic was taken of “Mammoth,” the next rock abrasion tool target on Wooly Patch.

OPPORTUNITY UPDATE: Opportunity Pokes Around Pig – sol 174-176, July 27, 2004

On sol 174, Opportunity completed close-up examination of a rock target called “Arnold Ziffel” using the rover’s microscopic imager, Mössbauer spectrometer and alpha particle X-ray spectrometer. All observations were successful.

Leaving Arnold Ziffel on sol 175, Opportunity backed up to capture an image the results of the close-up work, and then moved on down slope to a new target. This move will leave the rover about 13 meters (about 43 feet) down from the lip of the crater. The rover was put into deep-sleep, energy-saving status overnight from sol 175 to sol 176.

Sol 176, ending on July 23, was a driving day. Opportunity moved down the slope (and east) to a position to investigate a target called “Diamond Jenness.” Everything executed as planned, leaving the rover in a great position to grind into the target with its rock abrasion tool.

The engineering team is looking into a concern about the driving surface. The downslope pavement requires close examination before the rover traverses, to ensure the sand covering the pavement is still capable of supporting Opportunity. Recent experience has shown up to 30 percent slip.