[meteorite-list] Mars Exploration Rover Update - June 22, 2004

[Ron Baalke]

http://marsrovers.jpl.nasa.gov/mission/status.html

OPPORTUNITY UPDATE: Edging Down 'Endurance' - sol 141-143, 
June 22, 2004

Opportunity is showing no signs of middle age as it 
continues to work in "Endurance Crater." The rover has 
spent the last few sols inching farther down into the 
crater, making observations and pushing the limits. 
Managing resources as the rover's tilt angle changes 
is challenging and keeps the rover planning team very 
busy.

On sol 141 Opportunity completed post-rock abrasion tool 
Mossbauer spectrometer observations on the rock called 
"Tennessee." Having spent the last four sols 
investigating Tennessee, Opportunity stowed its arm and 
moved deeper into Endurance Crater. A 0.70-meter (2.3 feet) 
drive positioned the vehicle to begin observations on the 
first contact point, a transition between two different 
geologic layers. As it turns out, after arriving at the 
rover's new location and taking images, there appears to 
be not one contact point, but three contact points all 
within reach of the arm. Opportunity then performed 2.5 
hours of remote observations using the panoramic camera 
and miniature thermal emission spectrometer. The rover 
then went into deep sleep mode for the night.

On sol 142 Opportunity begin another series of microscopic 
imager observations on three different targets: 
"Bluegrass," "Siula Grande" and "Churchill." The rover 
then performed alpha particle X-ray spectrometer and 
Mossbauer spectrometer integrations overnight.

On sol 143 Opportunity again used its rock abrasion tool, 
but not without some consternation from the uplink team. 
In order to grind using the rock abrasion tool, a minimum 
of force must be used to push the tool onto the target. 
With the vehicle tilted 23.2 degrees, there was concern 
that applying too much force could cause the vehicle to 
lose traction on the slope and slide farther into the 
crater, possibly damaging the arm. Concerns were 
pacified when the rock abrasion tool operation worked 
flawlessly, abrading approximately 3 millimeters (about 
0.12 inches) into the rock called "Cobble Hill."