Mars rover Spirit could wriggle free of its sandy trap

A NASA scientist has said that the Mars rover Spirit should be able to wriggle free of its sandy trap on Mars, and not become a stationary lander mission.

In April 2009, Spirit's wheels broke through a thin surface crust and got mired in the loose sand below.

After months of trying unsuccessfully to free the rover, NASA declared on January 26 that Spirit would henceforth be a stationary lander mission rather than a rover.

But, according to a report in New Scientist, rover scientist Ray Arvidson of Washington University in St Louis, Missouri, said that the announcement was "a little bit premature".
 
In nine drives between January 15 and February 8, mission members coaxed the rover into driving backwards by 34 cm - "pretty good for a lander", Arvidson said.

That far surpasses the mere millimetres of motion Spirit had managed in previous efforts.

The technique involved swivelling the rover wheels from side to side, which cleared away some of the loose soil beneath the wheels and compacted what remained.

By alternating wheel swivelling with short drives, the rover was able to make slow and steady progress.

"We only stopped because we ran out of sunlight" as winter approached, Arvidson said.

Spirit is hibernating now, with too little power to continue driving.

"After we come out from hibernation in September or October, my suspicion is that a couple weeks (of driving) and we'll back out (of the trap)," he said.