May 12, 2003. Copyright 2002. Graphic News. All rights reserved.

Red rovers head for Mars

LONDON, May 12 Graphic News: The U.S. space agency NASA has started the countdown to the launch of two robotic buggies on a mission to find out if there is, or ever was, life on Mars.

NASAÕs twin rovers are set to be launched on June 6 and June 25, piggy-backing on two rockets then parachute down to the Red Planet in January, swaddled in a cocoon of airbags.

The 400-pound (180-kg), desk-sized rovers are much larger than the 1997 Pathfinder mission with its 23-pound (10-kg) Sojourner vehicle which scurried about 100 yards (90 metres). Each six-wheeled rover can move at a top speed of roughly two inches a second -- about the same as a tortoise -- and travel about 1,100 yards (1,000 metres) picking up and examining Martian rocks and taking pictures for transmission back to earth.

NASA took more than two years to choose landing sites once possibly hospitable to life. One is the Gusev crater into which a now-dry river apparently once emptied, perhaps filling the basin with a brimming lake. The other is the Meridiani Planum, a plain that is rich in hematite, an iron oxide mineral that typically forms in water.

The sites, halfway around the planet from each other, are within a narrow band of the planetÕs equator to ensure the solar-powered rovers receive enough sunlight.

ÒInterest in Mars has really hotted up since indications of water-ice raised the question again about whether life has evolved there,Ó said Dr Charles Elachi, director of NASAÕs Jet Propulsion Laboratory. Liquid water is seen as key for Earth-type life on a planet and underground water-ice could help show how Mars developed.

Each rover is equipped with a 5-foot-high (1.5-metre-high) mast-mounted camera providing stereoscopic 360 degree views of the cold, rocky terrain and has a robotic arm that can press instruments against rock and soil for clues that water was once present on the surface of Mars. 

Elachi said the rovers would be able to transmit information about Mars, once they arrived, for between 90-120 days  depending on amounts of sunlight.

Each carries eight, 0.1-ounce (2.8-gramme) pellets of radioactive plutonium dioxide that generate one watt of heat apiece to keep the robots warm at night. Once winter hits Mars, with temperatures plummeting to minus 300 Farenheit (150 degrees Centigrade), the rovers will run out of energy.

The $800 million double mission marks NASAÕs second and most ambitious bid yet to roam the surface of Mars.

ÒWhat weÕre trying to do is put two field geologists on the surface of Mars,Ó mission science manager John Callas said. ÒWhat does a field geologist do? It uses its senses and arms and legs. WeÕve designed a robotic vehicle that mimics those capabilities.Ó

Mars has been the site of some of the space agencyÕs biggest triumphs and some of its most humiliating failures, too. NASA lost two spacecraft at Mars in 1999. Sending two rovers is seen as a way to increase the chances of success.

The two rovers will be part of an international flotilla of spacecraft expected at Mars by 2004. It will include no fewer than four orbiting satellites from Europe, Japan and the United States, and another lander, the British Beagle 2.
/ENDS

Sources: NASA, Jet Propulsion Laboratory