Slim progress in freeing Mars rover Spirit

LOS ANGELES, Nov. 17 (Xinhua) -- The Mars rover Spirit on Tuesday made its first attempt in six months to move out of a sand trap on the red planet, but stopped in less than a second after it began, the U.S. space agency NASA said.

According to NASA, a tight limit on vehicle roll and pitch of less than one degree change was set for this first drive. As the rover began its first move, it sensed that its roll was outside the allowed limit and safely stopped the drive.

Initially, the commands sent to Spirit were for it to make two forward motions, rotating its wheels three revolutions each step. If the rover were on solid ground, that would have carried it about five yards (4.5 meters).

Scientists are "still analyzing that result before they decide what to do with the next drive," said Guy Webster, spokesman at the Jet Propulsion Laboratory (JPL) in Pasadena, California, which operates two rovers on Mars, Spirit and Opportunity.

The project was starting cautiously, setting initial parameters with very tight limits with the knowledge that these hair triggers may stop the rover frequently, said NASA.

From this limited drive, the operating team now has a more accurate measurement of vehicle roll and pitch that will be used for subsequent drive planning.

Scientists at JPL has cautioned that the attempt to extract Spirit from the Martian sand trap is expected to take weeks or months, and no one is sure whether they can successfully rescue the rover.

Even if the rover never gets out of the sand trap, its scientific value could continue as a weather and seismic monitoring station, according to NASA.

Spirit, which landed on Mars in January 2004, has been stuck on Mars at a site scientists call "Troy" since April 23 this year.