U.S. JPL prepares commands to free Mars rover Spirit

LOS ANGELES, Nov. 16 (Xinhua) -- Scientists at the Jet Propulsion Laboratory (JPL) started Monday to prepare driving commands for the Mars rover Spirit to exit a sand trap on the Red Planet, NASA announced.

These commands would be transmitted to Spirit at 1 a.m. PST Tuesday morning (1500 GMT Monday).

It is the first attempt JPL is making to save the rover since it was trapped on Mars about six months ago.

According to NASA, Spirit would be instructed to drive straight ahead (north) in two steps. Each step would be a commanded wheel motion of about 2.5 meters. At the conclusion of the commanded motion, the rover would collect a three-frame Microscopic Imager mosaic of the rover underbelly.

Spirit would also collect Pancam images of the middle wheels, pre-drive and post-drive visual odometry (Visodom), Navcam images, and supporting front and rear Hazcam images, NASA said.

The rover would drive with the robotic arm (Instrument Deployment Device) already deployed in the "fishing stow" position, so it can take Microscopic Imager images without having to stow and un-stow the arm before and after each drive, according to NASA.

A team of scientists expect to spend the whole day Tuesday analyzing the drive results before the next drive attempt would be made, possibly on Wednesday, Nov. 18.

NASA said at least initially, little actual motion of the rover would be observed.

According to NASA, the attempt to extract Spirit from the Martian sand trap was expected to take weeks or months, if at all possible.

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