NASA's Mars-exploring Spirit rover received its commands Tuesday to attempt an escape from a sand trap, but it made little progress because of a precarious tilt, mission managers reported.
Spirit has been stuck in the Martian dirt since April, when it drove into a spot of soft terrain called "Troy" back in April.
Mission managers sent the drive commands to Spirit at 4 a.m. ET Tuesday. But the rover's wheels spun for less than one second because it sensed more lateral tilt than it was allowed.
Rover drivers have allowed the robot less than one degree of roll and pitch until they are more confident with the rover's movements during the extrication process.
Mission managers spent the past six months devising an escape plan to move the rover out of the sand pit. They tested them with model rovers back on Earth that are essentially replicas of Spirit and its twin, Opportunity.
Rover drivers decided that the best strategy would be to have Spirit backtrack, moving forward to retrace the tracks that brought it into its current predicament. (The rover's broken right front wheel has meant that Spirit's primary mode of driving is backwards.)
After those two steps, Spirit was supposed to take a three-frame Microscopic Imager mosaic of its underbelly where a rock may be touching the rover. The placement of that rock has complicated the escape attempt.
Spirit was also to snap pictures of its middle wheels, its pre- and post-drive positions and the area around it with its front and rear Hazcam camera systems.
The rover team spent Tuesday analyzing the data Spirit sent back and will decide what steps to take next, whether to continue on with the same strategy or try something different, only after that data has been analyzed. The commands for Spirit's next move will be completed no sooner than Wednesday, according to the latest report.
Mission managers warn that the process to free Spirit, which has been on Mars for nearly six years now, is likely to be slow and take several weeks.
Spirit and Opportunity both landed on Mars in January 2004.