[meteorite-list] Mars Rover Opportunity Update: July 31 - August 4, 2015

[Ron Baalke]

OPPORTUNITY UPDATE: Looking Forward to Contact Science in 'Marathon Valley', 
sols 4094-4098, July 31, 2015-August 04, 2015

Opportunity is in 'Marathon Valley' on the west rim of Endeavour Crater, 
searching for clay minerals. 

The rover is operating in persistent RAM mode (not using Flash for data 
storage). This requires the rover to stay awake all the way up to the 
Ultra-High Frequency (UHF) relay passes on each sol. With Mars Odyssey 
now in a later orbit, relay passes come much later in the day. With winter 
coming and less sunlight for energy production, these late relay passes 
cause the rover to consume more energy from the batteries. Therefore, 
Sols 4095 and 4097 (Aug. 1 and Aug. 3, 2015) had little science and a 
shorter relay pass to save energy for a drive on Sol 4096 (Aug. 2, 2015). 
The drive successfully completed, moving the rover over 65.6 feet (20 
meters) towards a new geologic unit within the valley. Extensive post-drive 
Navigation Camera (Navcam) panoramas were also collected. 

With a good state of charge after the recharge sol on Sol 4097 (Aug. 3, 
2015), Opportunity drove again on Sol 4098 (Aug. 4, 2015), moving just 
under 19.7 feet (6 meters) to reach an exposed outcrop within this new 
rock unit. The plan ahead is to perform some contact science measurements 
on the targets in this area. 

During the winter, Opportunity will rely more on the Mars Reconnaissance 
Orbiter for relay, which occurs earlier in the day. Other than the Flash, 
Opportunity is in good health. 

As of Sol 4098 (Aug. 4, 2015), the solar array energy production was 431 
watt-hours with an atmospheric opacity (Tau) of 0.639 (from Sol 4096, 
Aug. 2, 2015) and a solar array dust factor of 0.614.

Total odometry is 26.41 miles (42.51 kilometers), more than a marathon.