Spirit is embedded and cleaner; Opportunity does contact investigation of pebbles

Spirit is embedded in loose, soft terrain on the west side of Home Plate. There is a real risk the rover may be high-centered (underside touching) on a small mound of rocks right under the belly of the rover. Additionally, a left wheel motor stall occurred during the last rover motion on Sol 1899 (May 6, 2009). No motion has been commanded since.

The project is engaged in a recovery activity. This involves extensive remote sensing observations by the rover of the local soil characteristics, and ground testing using the surface system testbed rover in the sandbox at JPL.

There has been no recurrence of the anomalous behavior that happened between Sol 1872 (April 9, 2009) and Sol 1881 (April 18, 2009). There is still no explanation for the previous anomalies, and the investigation is continuing.

The week provided more good news about solar array energy. Spirit experienced yet another substantial solar array dust cleaning event. On Sol 1900 (May 7, 2009), energy production improved by about 30 percent. With the significant improvement in energy, the rover can now support morning UHF relay passes, which will help with the backlog of collected data onboard. The Mars Odyssey project has made special efforts to support this additional relay.

As of Sol 1905 (May 13, 2009), solar array energy production is estimated around 652 watt-hours, with atmospheric opacity (tau) at 0.774. The dust factor has improved substantially to 0.678, meaning that 67.8 percent of sunlight hitting the solar array penetrates the layer of dust on the array. As of Sol 1906 (May 14, 2009), Spirit's total odometry remains 7,729.93 meters (4.80 miles).

Opportunity has been using its robotic arm (instrument deployment device, or IDD) to conduct a contact science investigation of small pebbles located on exposed rock outcrop.

On Sol 1881 (May 9, 2009), Opportunity took a special image with the microscopic imager of the left-front wheel. This tested a technique that might be used by Spirit to assess the state of Spirit's embedded wheels.

The alpha-particle X-ray spectrometer (APXS) was positioned on a pebble target for an overnight integration. On the next sol, the APXS was moved to a new target. On Sol 1884 (May 12, 2009), the rover backed away from these targets and then moved about 6 meters (20 feet) into a new position for more IDD work. The right-front wheel, which had shown elevated motor currents, exhibited improvement in the current levels after resting at these contact-science targets.

As of Sol 1884 (May 12, 2009), Opportunity's solar array energy production was 460 watt-hours, with atmospheric opacity (tau) around 0.732 and the dust factor at 0.581. Opportunity's total odometry as of Sol 1885 (May 13, 2009) is 15,908.93 meters (9.89 miles).

 

Source: Jet Propulsion Laboratory
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