Stuck Mars Rover Finally Budges, a Little
This image shows the progress of Spirit after its second drive attempt. (Click on the image for a "before" and "after" animation.) In the "after" image, Spirit's left-front wheel has become slightly less buried in the soft soil in which the rover had become embedded about six months ago. The right-front wheel, which has not been usable for driving since 2006, has been pushed perceptibly forward by the drive. The amount of forward motion is less than one percent of the distance that would have been covered on firm ground by the amount of wheel rotation commanded in the drive.
Credit: NASA/JPL-Caltech

NASA?s stuck Mars rover Spirit took a tiny step Thursday, its first progress in months, during the latest attempt to extricate the robot from deep Martian sand.

On Thursday, Spirit inched forward slightly after its second attempt to drive out of the patch of sandy soil called Troy, in which it has been mired since April.

The rover successfully completed the first of two commands to spin its wheels for a period equivalent to driving 8.2 feet (2.5 meters). The attempt moved Spirit?s center forward by about half an inch (1.2 cm), left by about 0.3 inches (7 mm), and about ?0.2 inches (4 mm) down.

Some small forward motion was observed with the non-operable right front wheel, and the left front wheel showed signs of climbing, despite the center of the rover moving downward. These motions are too small to establish any trends at this time, the NASA report said.

The plans for the drive limited Spirit's movement to 0.4 inches (1 cm) in any direction, so the rover didn't attempt the second wheel spin because it calculated that it had exceeded that limit.

The first attempt to free Spirit, which took place on Tuesday, hit a snag when the rover sensed it was tilting too much and stopped after less than one second of wheel spin.

The rover team is continuing to analyze the data and images from the second drive, NASA said.