Mars rover gets ready to roll

Spirit sent a picture showing wheels locked in place (right and left)

The Spirit Mars rover has completed manoeuvres which should allow it to explore the planet surface within days.

Twelve pyrotechnic devices were fired successfully, moving the craft onto its six wheels, Nasa scientists said.

Concerns remain that an airbag used to protect the rover during landing could hamper its route to the surface.

So mission controllers now plan to rotate Spirit 120 degrees before rolling it along what they hope is a clear path to the ground on Wednesday.

Unfolding Spirit's wheels and getting it to "stand up" was the latest success for the US space agency's (Nasa) mission to Mars.

Chris Voorhees, an engineer in charge of the process, said it was "intense" to witness the procedure which was met by cheers at mission control in Pasadena where the team played Bob Marley's "Get Up, Stand Up" reggae anthem.

He said it was "one of the most complicated deployments that has ever been done on a robotic spacecraft".

"We have left Spirit in a very comfortable position. She is asleep right now, comfortable on all six wheels."

Click here for a diagram of the Spirit Mars rover

Rotation plan

But further checks on the position of the airbags which cushioned the rover as it landed confirmed fears that one might impede the exit of the surface explorer.

Mission manager Jennifer Trosper told reporters that the raised airbag could have touched, and possibly damaged, one of Spirit's vital solar panels.

After running through other strategies at Nasa's Jet Propulsion Laboratory, it has been decided to try to rotate the vehicle.

A full 360-degree panorama will come in a few days

Enlarge Image

Now pointing south, the goal was for Spirit to be turned and then rolled off the landing craft towards the north-west as it began to explore the Gusev Crater, she said.

Nasa team members had wanted to drive the rover off the front ramp as planned originally but that idea has now been abandoned.

The rotation is now scheduled for late Monday California time and the drive on to the surface of Mars has been brought forward again to late Tuesday (Wednesday GMT).

Even in its parked position, the Spirit had already been able to provide a great deal of data to scientists on Earth, Ms Trosper said.

Cool colours

Among its transmissions have been stunning colour images of the Red Planet, allowing scientists a detailed look at the landing site.

The Mini-Tes data show rock and soil temperatures as different colours

And some initial data has been returned from the Mini-Thermal Emission Spectrometer. This instrument sees infrared radiation, or heat, emitted by objects.

By measuring the brightness of that emission in 167 different "colours" of infrared for each point it views, the Mini-Tes can work out from afar the mineral composition of Martian rocks and soils.

This will help scientists decide which boulders to roll up to for further investigation.

Water clues

Traces of carbonate minerals showed up in the rover's first survey of the site with the instrument.

Carbonates form in the presence of water, but it is too early to tell whether the amounts detected come from interaction with water vapour in Mars' atmosphere or are evidence of a watery local environment in the past, the scientists emphasise.

"We came looking for carbonates. We have them. We're going to chase them," said Dr Phil Christensen of Arizona State University, Tempe, leader of the Mini-Tes team.

Nasa targeted Spirit at Gusev Crater because from-orbit pictures suggested the area may once have held a lake.

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