The National Aeronautics and Space Administration (NASA) scientists sent the robotic rover Spirit out for its first spin on martian soil yesterday, commanding the six-wheeled vehicle to roll off its landing platform a dozen days after it arrived on the red planet.

Radio signals instructing Spirit to make its initial excursion were beamed to Mars at 14:21 pm Beijing Time (0821 GMT), and confirmation that the rover had ventured onto the planet's surface came with a return transmission about an hour and 40 minutes afterward.

Moments later, mission controllers received the first pictures by the rover looking back at the lander, showing tracks left by Spirit in the martian soil.

The brief outing took Spirit only about 3 metres straight ahead but was cheered by project managers at the Pasadena-based Jet Propulsion Laboratory (JPL) as a successful prelude to Spirit's mobile search for signs of life-sustaining water.

"We are definitely on the surface of Mars,"declared Rob Manning, one of NASA's project managers. "Being on the soil marks a major turning point for the project."

If all goes as planned over the next 78 days, the golf cart-sized explorer will roam its surroundings in Gusev Crater, a barren, wind-swept basin about the size of Connecticut that scientists believe may have been the site of an ancient lake bed once fed by a long, deep martian river.

Spirit already has sent back stunning, three-dimensional, colour photographs of Mars revealing the planet's terrain in vivid, unprecedented detail. The JPL team is even more eager to closely examine soil and rocks using a collection of high-tech geologic gadgets carried on the rover's robot arm.

Spirit's first jaunt away from the landing pod in which it bounced to the martian surface on January 3 comes as NASA looks forward to a new era of human space exploration called for on Wednesday by President George W. Bush, including the eventual goal of sending astronauts to the red planet.

Spirit is the fourth probe ever to successfully land on Mars, following in the footsteps of two Viking landers in the 1970s and the Pathfinder mission in 1997.

On January 24, Spirit's twin rover, named Opportunity, is scheduled to land on the opposite side of the planet for its own three-month mission.

JPL controllers plan to aim an instrument called a mini-thermal emission spectrometer, or mini-TES, upward to obtain a reading of infrared radiation emitted by particles in the martian sky at the time the European obiter Mars Express snaps the same type of images from 300 kilometres overhead.

(China Daily 01/16/2004 page7)