NASA Still Hopeful For Mars Rover Revival
By Guy Norris
Scientists at NASA's Jet Propulsion Laboratory (JPL) trying to figure out escape maneuvers for the stranded Spirit rover on Mars have received some partial good news after tests of the vehicle's left middle wheel show it is operating normally.
The tests have been conducted over recent days to assess whether the problem might be associated with the wheel itself, rather than the vehicle simply becoming bogged down or grounding on a small area of rocky soil.
Operations with Spirit were suspended on May 7 when signals showed the left middle wheel was jammed, while the other wheels were apparently dug into the surface up to their hubs. JPL engineers are planning to run tests of the Earth-based rover over a section of simulated Martian soil to develop the best maneuvers for extracting Spirit, and in the meantime continue to probe the vehicle for clues (Aerospace DAILY, May 22).
Last week JPL commanded one- and four-degree movements of the suspect center wheel, both of which resulted in positive reactions. "We have subsequently performed a 16-degree backward movement and that went as planned. Everything so far has been indicating a nominally operating, unobstructed wheel in the backward direction. We'll await the results of further ground testing, but results so far are encouraging," says Spirit and Opportunity project manager John Callas.
The start of the ground tests themselves has been delayed because of a computer issue at JPL involved in control of the rover at the laboratory. "We're attempting to recover files lost as a result of the failed disk controller, which is a slow and complex process," Callas says. "We're also exploring parallel options. One is to use the Surface System Test Bed rover lite [SSTB Lite] to do some stand-alone testing of the rover mobility system in various soil simulants."
Spirit photo: NASA
