SPIRIT UPDATE: Just a Little Rock Abrasion Tool - sol 167-170, June 30, 2004
On sol 167, Spirit looked at a bit of soil called "Jaws" with the alpha particle X-ray spectrometer and microscopic imager. Then the rover completed a drive intended to put it into position to analyze "Pot-of-Gold" with the instruments on its robotic arm. The drive moved Spirit farther than expected though, and the rover ended up directly over the rock. That position prevented any observations with the instrument deployment device.
On sol 168, rover planners commanded Spirit to "bump" backward, into a position where the rock abrasion tool could make contact with Pot-of-Gold. This was successful, and Spirit spent the rest of the time taking images of the surrounding area with its panoramic and navigation cameras.
On sol 169, Spirit successfully operated its rock abrasion tool on Pot-of-Gold, grinding away the top .2 millimeters (.008 inches) of rock from the high points. The procedure took 1 hour and 45 minutes. Pot-of-Gold posed a special challenge to the rover team because it is quite small -- only slightly larger than the rock abrasion tool instrument itself. The rock abrasion tool inflicts about 6.8 kilograms (15 pounds) of pressure on its rock targets, and smaller rocks aren't necessarily stable enough to resist this.
Before and after pictures of Pot-of-Gold showed that the rock was moved by the rock abrasion tool procedure. That movement, plus possible slippage where the tool contacts the rock, resulted in only intermittent contact during the grinding operation. After the grind was complete, Spirit placed the alpha particle X-ray spectrometer on the freshly exposed area in preparation for an operation later that night.
On Sol 170, Spirit awoke to stop the alpha particle X-ray integration, took miniature thermal emission spectrometer and panoramic camera images of some local track marks, took more microscopic images of the newly exposed Pot-of-Gold, then placed the MÃ¶ssbauer instrument on the site for a 21-hour overnight observation.
OPPORTUNITY UPDATE: Rock Abrasion Tool Hops from 'Virginia' to 'London' - sol 144-149, June 29, 2004
While Opportunity is hard at work inside "Endurance Crater," engineers at JPL are busy testing engineering models in the Lab's simulated martian environment. A tilt platform is being used to determine Opportunity's ability to climb back up over the "curb" below its current location.
On sol 144, Opportunity completed the MÃ¶ssbauer spectrometer integration on the rock abrasion tool hole on the "Cobble Hill" area. Microscopic images were also collected.
Sol 145 was a busy day, with the rover collecting more post-rock abrasion tool Cobble Hill and pre-"Virginia" microscopic images. The tool then bored a 4.3-millimeter (0.17 inches) hole in Virginia. Deep sleep mode was invoked for the overnight hours.
Sol 146 was used to examine the newly-abraded hole with the microscopic imager and the alpha particle X-ray spectrometer.
On sol 147 the rover performed a long MÃ¶ssbauer spectrometer integration on Virginia and completed some remote sensing from its location in the crater. After relaying the data through both Mars Global Surveyor and Mars Odyssey, Opportunity went into deep sleep mode for the night.
"London" was Opportunity's target on sol 148. The rock abrasion tool ground a 4.5-millimeter (0.18 inches) hole in the rock. The alpha particle X-ray spectrometer was then placed on the hole for integration.
On sol 149 the rover continued to scrutinize London with the alpha particle X-ray spectrometer and the microscopic imager. A MÃ¶ssbauer spectrometer integration was initiated and will be completed on sol 150. Deep sleep mode was invoked for the overnight hours.