[meteorite-list] Mars Exploration Rover Update - June 30, 2004

[Ron Baalke]

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

SPIRIT UPDATE: Just a Little Rock Abrasion Tool - sol 167-170, 
June 30, 2004

On sol 167, Spirit looked at a bit of soil called "Jaws" with 
the alpha particle X-ray spectrometer and microscopic imager. 
Then the rover completed a drive intended to put it into 
position to analyze "Pot-of-Gold" with the instruments on 
its robotic arm. The drive moved Spirit farther than expected 
though, and the rover ended up directly over the rock. That 
position prevented any observations with the instrument 
deployment device.

On sol 168, rover planners commanded Spirit to "bump" backward, 
into a position where the rock abrasion tool could make contact 
with Pot-of-Gold. This was successful, and Spirit spent the 
rest of the time taking images of the surrounding area with 
its panoramic and navigation cameras.

On sol 169, Spirit successfully operated its rock abrasion 
tool on Pot-of-Gold, grinding away the top .2 millimeters 
(.008 inches) of rock from the high points. The procedure 
took 1 hour and 45 minutes. Pot-of-Gold posed a special 
challenge to the rover team because it is quite small -- only 
slightly larger than the rock abrasion tool instrument itself. 
The rock abrasion tool inflicts about 6.8 kilograms (15 pounds) 
of pressure on its rock targets, and smaller rocks aren't 
necessarily stable enough to resist this.

Before and after pictures of Pot-of-Gold showed that the rock 
was moved by the rock abrasion tool procedure. That movement, 
plus possible slippage where the tool contacts the rock, 
resulted in only intermittent contact during the grinding 
operation. After the grind was complete, Spirit placed the 
alpha particle X-ray spectrometer on the freshly exposed area 
in preparation for an operation later that night.

On Sol 170, Spirit awoke to stop the alpha particle X-ray 
integration, took miniature thermal emission spectrometer and 
panoramic camera images of some local track marks, took more 
microscopic images of the newly exposed Pot-of-Gold, then 
placed the Mo"ssbauer instrument on the site for a 21-hour 
overnight observation.