[meteorite-list] Mars Rover Opportunity Update: Jul 21-30, 2015

[Ron Baalke]

OPPORTUNITY UPDATE: Beginning to Explore 'Marathon Valley',
sols 4085-4093, July 21, 2015-July 30, 2015

Opportunity has entered 'Marathon Valley' on the west rim of Endeavour 
Crater and has begun the search for clay minerals. 

Previously, the project tested returning to using Flash memory for data 
storage. The Flash exhibited instability after a few sols, so the project 
returned Opportunity to operating in RAM-only mode on Sol 4085 (July 21, 
2015). Over the next two sols a 360-degree Navigation Camera (Navcam) 
panorama was collected. 

On Sol 4088 (July 24, 2015), the rover resumed contact science with the 
collection of a Microscopic Imager (MI) mosaic of a surface target followed 
by the placement of the Alpha Particle X-ray Spectrometer (APXS) on the 
same for a multi-hour integration. Additional MI images were collected 
on the next sol to complete the mosaic. Atmospheric observations were 
also made as part of this multi-sol plan. 

On Sol 4091, (July 28, 2015), the Rock Abrasion Tool (RAT) was used to 
brush the surface target to prepare it for further investigation. This 
was followed by another MI mosaic and the placement of the APXS. On Sol 
4093 (July 30, 2015), an offset MI mosaic was collected and the APXS placed 
on the offset target. Other than the Flash, Opportunity is in good health. 

As of Sol 4092 (July 29, 2015), the solar array energy production was 
424 watt-hours with an atmospheric opacity (Tau) of 0.695 and a solar 
array dust factor of 0.611.

Total odometry is 26.40 miles (42.48 kilometers), more than a marathon.