[meteorite-list] Mars Exploration Rover Update - July 2, 2004

[Ron Baalke]

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

SPIRIT UPDATE: Moving On From 'Pot-of-Gold' - sol 171-174, 
July 02, 2004

On sol 171, Spirit continued its investigation in "Hank's 
Hollow" and the rock target "Pot-of-Gold." The rover 
successfully completed observations of the abraded area 
with the microscopic imager and alpha particle X-ray 
spectrometer.

On sol 172, Spirit looked at the sky with the miniature 
thermal emission spectrometer and panoramic camera. The 
rover also acquired some thermal inertia observations of 
nearby soil with the miniature thermal emission 
spectrometer. Spirit finished up its Pot-of-Gold 
observations with some microscopic images and a final 
long Mossbauer integration of the abraded surface.

On sol 173, Spirit performed atmospheric observations 
with the miniature thermal emission spectrometer and 
panoramic camera. The rover also took some panoramic 
camera context images for the sol 172 thermal inertia 
observations. The rover finished the day's work by 
stowing the instrument deployment device and doing a 
"bump-back" to the "Bread Box" target. One last 
panoramic camera shot of Pot-of-Gold ended up a bit 
overexposed and will need to be retaken.

On sol 174, Spirit began the day acquiring atmospheric 
observations with the mini thermal emission spectrometer 
and panoramic camera. The rover then imaged the drive 
direction with the panoramic camera. Last but not least, 
Spirit took a look at a disturbed area of soil called 
"Bright Tracks" with the panoramic camera to help 
scientists learn more about the very bright material 
found here.

During the next 15 or more sols, rover planners will 
perform a "3,000 meter tune-up" on Spirit before the 
rover embarks on a climb up the hills.

The tune-up will include a number of elements including:

A front hazard avoidance camera calibration where a 
series of robotic arm poses and hazard avoidance camera 
images will be used to refine the rover planners' 
ability to target objects using stereo hazard avoidance 
camera images. The team is currently experiencing a 2 to 
3 centimeter (slightly less or slightly greater than an 
inch) error in predicted versus actual target locations 
in the vicinity of the instrument deployment device.

Spirit's first deep sleep. Deep sleep is a mode that 
leaves the rover completely un-powered overnight, 
saving the energy that would be spent powering rover 
electronics and survival heaters that are normally on 
even when the rover is napping. Spirit needs deep 
sleep to save energy in the coming sols. Since deep 
sleep is potentially harmful to the mini thermal 
emission spectrometer instrument because its survival 
heater is not powered, rover planners have identified 
two observations that must be completed before the 
first deep sleep is attempted. Opportunity has been 
using deep sleep for several weeks now.

A right front wheel lubrication. Spirit's right front 
wheel continues to draw roughly twice the current of 
the other wheels. Spirit will drive to "Engineering 
Flats," a relatively flat, hazard-free area where 
rover planners will execute a series of diagnostic 
drive tests and heating sequences over the course of 
four to five sols. The intent is that the heating 
will re-flow the lubricants in this actuator, 
correcting the problem. Engineering Flats is roughly 
7 meters (nearly 23 feet) from Spirit's current 
location.

Engineering tests of visual odometry. Visual odometry 
uses navigation camera images taken during a drive to 
determine the rover's location. This rover feature 
has been improved and is ready for trial runs now. 
Rover planners would like to use it on a regular 
basis to get Spirit where they want it to go more 
quickly. Due to slippage, Spirit sometimes needs 
two or more sols to make a short approach when 
using the blind drive technique.