Opportunity approaching 'Concepcion' crater rim; Spirit prepares for winter

Opportunity has been driving towards "Concepcion," a 10-meter (33-foot) diameter crater to the south of Marquette Island.

Concepcion crater is assessed to be geologically very young with visible rays of ejecta radiating from the center of the crater. The Sol 2136 (Jan. 26, 2010), imagery shows many fragments of ejecta on the surface all around the crater. Opportunity is currently 20 meters (66 feet) north of the crater's rim.

In the plan ahead, Opportunity will approach within about 3 meters (10 feet) of the rim and begin a clockwise circumnavigation imaging campaign. Large eject fragments that would allow direct measurement with the Alpha Particle X-Ray Spectrometer (APXS) and the Mössbauer (MB) spectrometer are potential candidates for in-situ (contact) investigation. Opportunity will continue on towards Endeavour Crater once the Concepcion campaign is completed.

The right-front wheel currents continue to be well-behaved. No improvement has been observed yet in the miniature thermal emission spectrometer (Mini-TES) elevation mirror, which continues to opened regularly for allow cleaning by the wind.

As of Sol 2136 (Jan. 26, 2010), the solar array energy production was 296 watt-hours with an atmospheric opacity (tau) of 0.458 and a dust factor of 0.517. Total odometry is 19,302.88 meters (12 miles).

 

Spirit is still embedded in the area called "Troy" on the west side of Home Plate. Energy levels for Spirit have been decreasing rapidly as winter approaches. To prepare for winter, the project is taking actions to improve northerly tilt of the rover to maximize solar illumination.

The best approach has been to drive Spirit backwards. The drives employ a wheel steering action "frog kick" with each drive step. To mitigate against wheel stalls associated with driving in this embedded terrain, an autonomous wheel diagnostics has been added. If a wheel stall occurs, the diagnostic test is run on the stalled wheel. If the wheel passes the diagnostic, then driving resumes. This has been effective in permitting the driving to continue much further than otherwise.

Spirit continues to make several centimeters of backward progress with each drive without further sinkage. In some cases, the rover has gained in elevation. However, northerly tilt has not improved due mainly to the counterclockwise yaw of the rover. Backward driving will continue with the aim to position the rover for the winter with the most favorable orientation achievable.

As of Sol 2158 (Jan. 28, 2010), the rover solar array energy production was down to 182 watt-hours with an atmospheric opacity (tau) of 0.379 and a dust factor of 0.522. Total odometry is 7,730.46 meters (4.80 miles).

 

Source: Jet Propulsion Laboratory
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