PASADENA. California. Feb 1: A six-wheeled rover about 3 feet (1 metre) high should be Jerking across the surface of Mars and giving scientists their first look at the planet's composition soon after a July 4,1997. landing, reports AP.

On Wednesday, engineers at NASA's Jet Propulsion Laboratory showed off the rover, named Sojourner, and the Mars Pathfinder that will protect it during the endof-Klaunch and seven-month ley to Mars

Tney Invited reporters to vacuum off and suit up before entering the spacecraft assembly clean room where Pathfinder. its rover, parachute, antennas and airbags are being prepared for additional

ore-launch testing.

Pathfinder takes off December 2. 1996. from Cape Canaveral.

This is actually the first and last time that we Will see Pathfinder and Sojourner completely assembled until Just before launch." said Brian Muirhead. Pathfinder flight system manager and Wednesday’s tour guide.

The Pathfinder lander weighs 772 pounds and stands about 3.^ feet tall. Three solar panels unfold to reveal the rover stowed inside, along with antennas, a panoramic-view camera and even tiny wind socks that will take part of a planetary weather report.

When Pathfinder lands

during the Martian summer, daytime temperatures will be about freezing, while at night they slip a couple of hundred degrees.

If all goes according to plan, the Smithsonian Institution in Washington could be putting out a daily Martian weather report with information gleaned by Pathfinder, said David Budov. Mars Pathfinder project secretary.

During the trip through space. Pathfinder will be guided by both sun sensors and star sensors and an an tenna that lets it communicate with Earth.

Pathfinder will enter the martian atmosphere — only

found on Earth — at 17.000 mph (27.000 kilometres per hour). It will slow within two minutes to 900 mph (1.400 kilometres per hour) before its parachute opens.

Seconds later, its red-hot heat shield will fall away, the lander will separate from a protective outer shell and at an altitude of about 100 feet (30 metres), a giant cocoon of air bags will inflates.

The cocooned craft will bounce before coming to rest somewhere In Ares Vallis, an ancient flood basin likely to contain many kinds of rocks.

Pathfinder's airbags will retract, daylight will come and provide the solar power for tne 22-pound (10 kilogram) rover to rise on its

metal haunches and roll down a ramp to the Martian surface.

There, the steel-wheeled rover will be guided by a laser navigation system that tells it when to avoid deep depressions and big rocks. For anywhere from seven to 30 days, it will roll up to rocks, where an instrument called an alpha proton X-ray spectrometer will shoot out alpha particles whose bouncing paths tell scientists what the rocks are made of.

The entire hlstoiy of the planet is held In rocks," said Howard Eisen, lead mechanical engineer for the rover.

"We re going to find a lot of iron,* said Donna Shirley, programme manager for the

Mars exploration office. "Mars is rusty. That's why it's red, from iron oxide."

Dubov explained that Pathfinder will do more than the two Viking missions that landed on Mars in 1976. which stayed put and extended their robotic arms to sample the surface.

In today's dollars, the Viking missions would coat dlrs 3 billion, Shirley said. In contrast. Pathfinder la a bar-SS“less than 300 million

Pathfinder will be arriving on the 20th anniversary of Viking, part of a line of cheaper, smaller Discovery missions that can be developed and launched quickly.