Mars exploration rover Spirit resumes driving

Washington, Apr 25 (ANI): For the first time since April 8, NASA's Mars Exploration Rover Spirit went on a drive on April 23.

The drive took Spirit about 1.7 meters (5.6 feet) toward destinationsbout 150 meters (about 500 feet) away.

The engineers facilitated the drive while they investigate bouts of amnesia and other unusual behaviour exhibited by Spirit in the past two weeks.

Already, the rover has operated more than 20 times longer than its original prime mission on Mars.

This week, rover engineers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., judged that it would be safe to send Spirit commands for Thursday's drive.

The engineers were thinking if the rover experience another amnesia event, the day's outcome could be helpful in diagnosing those events.

Thrice in the past two weeks, Spirit has failed to record data from a day's activity period into non-volatile flash memory, which is a type of computer memory where information is preserved even when power is off, such as when the rover naps to conserve power.

"We expect we will see more of the amnesia events, and we want to learn more about them when we do," said JPL's Sharon Laubach, chief of the rover sequencing team, which develops and checks each day's set of commands.

Researchers are also investigating two other types of problems Spirit has experienced recently- failing to wake up for three consecutive communication sessions about two weeks ago and rebooting its computer on April 11, 12 and 18.

However, engineers have not yet found any causal links among these three types of events.

Last week, the researchers checked whether moving the rover's high-gain antenna could trigger problems, but routine communication via that dish antenna resumed on April 20.

Spirit has maintained stable power and thermal conditions throughout the problem events this month, although power output by its solar panels has been significantly reduced since mid-2007 by dust covering the panels.

"We decided not to wait until finishing the investigations before trying to drive again. Given Spirit's limited power and the desire to make progress toward destinations to the south, there would be risks associated with not driving," said Laubach.

Researchers have made a change in Spirit's daily routine in order to help in the diagnostic work if the rover experiences another failure to record data into flash memory. (ANI)