Mars rover opens eyes

NASA's Spirit probe has started beaming home snapshots from Mars, where it touched down three days into the new year.

Scientists at NASA celebrated the arrival of the rover, which will search for signs that the red planet was once capable of supporting life. NASA last landed a spacecraft on Mars in 1997, when the Sojourner rover of the Pathfinder mission explored the planet's surface.

Spirit is the first of a pair of rover devices due to land on Mars this month. Its sister probe, Opportunity, is now approaching Mars at the end of its seven-month flight from Cape Canaveral in Florida, and is scheduled to touch down on the opposite side of the planet on 24 January.

Spirit's wheeled rover vehicle has to complete a series of perilous manoeuvres and tests before it is ready to leave the lander and explore its surroundings. The Spirit project team at the Jet Propulsion Laboratory in Pasadena, California, anticipate that preparations for the Spirit rover's egress will take more than a week.

The rover vehicle is encased in a protective shell that has to unfurl like a flower opening its petals. This will create a platform from which it will eventually roll onto martian terrain - provided that it can avoid falling over or getting snagged in the deflated airbags that cushioned the lander's impact.

Once on the ground, the rover will deploy a battery of robotic limbs and instruments, powered by solar cells, to analyse the composition of martian minerals. It will focus on looking for signs that there was once liquid water on Mars. If water was present, it is possible that life once existed on the planet.

Spirit has landed in a huge crater called the Gusev Crater, which planetary scientists think might once have held a lake. A channel resembling a dry river valley leads into Gusev, and may have been carved by flowing water billions of years ago.

While Spirit prepares for its mission, its onboard camera is already active, and has just returned its first, somewhat gloomy, photo of the surrounding terrain in the Gusev Crater.

The current success of Spirit provides some welcome new year cheer after the suspected demise of Beagle 2, a Mars lander mission conducted by the European Space Agency. Beagle 2 was carried to Mars on board the Mars Express spacecraft, which is now orbiting the planet.

Beagle 2 was due to touch down on Christmas Day but has failed to communicate with its mother ship. Scientists are still scanning Mars in the hope of picking up Beagle 2's signature tune, but that hope is fading.

Mars Express is now adjusting its orbit in preparation for scanning the martian surface from on high. Its final orbit will bring it to within 300 km of the surface, from where it will also search for signs of frozen water beneath the martian soil.