Landing On Mars

As a fleet of robots from America and Europe nears the Red Planet, the question is less what the robots will find than how they can avoid the bad luck of many previous probes.

Medicine & Science

December 15, 2003|By Michael Stroh | Michael Stroh,SUN STAFF

WASHINGTON - They've sailed through searing solar flares and survived unexpected mechanical ticks. Now as an international fleet of robotic explorers closes on the Red Planet, the big question isn't what they'll find, but whether they'll land.

Delivering a spacecraft safely to Earth's nearest planetary neighbor is an engineering nightmare: Two-thirds of the 34 probes dispatched to Mars since 1960 have gone belly up.

"Some, including myself, call it the `death planet,'" declares Ed Weiler, NASA's associate administrator for space science.

Last week, the death planet claimed its latest victim: Japanese officials announced that Mars-bound Nozomi, launched in 1998 and due to arrive this week, was crippled beyond repair. The spacecraft, whose name means "hope," was supposed to study the Martian atmosphere and moons but it blew a thruster en route.

Next up: the spunky, British-built Beagle 2, a 73-pound machine designed to conduct the first sweep for Martian life in three decades. On Friday, the robot will peel away from its companion, the European Space Agency's Mars Express, in preparation for a Christmas Eve arrival. Mars Express, meanwhile, will swing into orbit to begin a two-year mission to map the planet surface.

Trailing in Beagle's fumes are the National Aeronautics and Space Administration's twin, $820 million golf-cart-size rovers. Landing on nearly opposite sides of the planet in January, Spirit and Opportunity will spend 90 days rumbling over the dusty soil in search of water.

Although the NASA rovers are generating the most buzz, the quirky Beagle 2, named after the vessel that carried 19th- century naturalist Charles Darwin around the South Seas, has the diehard cheering section. "Even though I work for NASA, I have to admit I'm rooting for Beagle," says Christopher McKay, an astrobiologist with the space agency's Ames Research Center in California.

The brainchild of Colin Pillinger, a planetary scientist at the United Kingdom's Open University, Beagle 2 began life as a sketch on the back of a beer coaster. Pillinger spent years pitching his clam-shaped craft to everyone from the British government to the European Space Agency, which finally agreed to give it a lift to the planet alongside its orbiter, Mars Express.

Grass roots aren't all that make Beagle unusual. When it touches down 9:54 p.m. EST on Christmas Eve, Beagle will announce its arrival with a nine-note, math-inspired melody composed by British pop band Blur. The craft will also calibrate its onboard camera with a polka-dotted canvas painted by London artist Damien Hirst.

But there's substance beneath the style. Beagle 2's sophisticated onboard lab will spend six months searching for chemical building blocks of life - the first direct search for extraterrestrial biology on Mars in 27 years. In 1976, twin U.S. Viking landers searched for life but sent back inconclusive results.

"If Beagle 2 does find something," says McKay, "it's going to completely eclipse the rover mission."

Meantime, NASA's Spirit and Opportunity will tackle an equally frustrating Martian mystery: Has the planet ever been lush and wet like Earth? Without water, scientists note, there is no chance of finding life as we know it.

"If you look at the surface of Mars today, it's cold, it's dry, it's barren. It's not an inviting environment for life," says Steven Squyres of Cornell University, the mission's science chief. "And yet we see these tantalizing clues."

From space, it appears that Mars was once awash in water. Pictures snapped by Viking and its successors show the same, lazy looping channels and sculpted banks formed by terrestrial rivers and lakes. Scientists also know that significant water-based ice sits below the surface at both poles.

But evidence gathered in recent years by Mars-orbiting spacecraft has muddied the debate. Scientists, for example, have found no carbonate minerals such as limestone, which they would expect if water had sloshed over the surface. Another strike: Scientists have detected minerals such as olivine on the surface. On Earth, olivine quickly disappears when water is around.

Finally, scientists who study the Martian atmosphere have argued that Mars would have been too cold for water to flow. "We see things that don't quite jibe with the picture of a wet Mars," says planetary geologist Bruce Jakosky of the University of Colorado.

NASA scientists spent two years picking the rover's landing sites from 155 areas where they suspect water once flowed. Sprit is aimed at Gusev Crater, a Connecticut-size bowl south of the Martian equator that looks like an ancient lake bed in orbital photographs.

Opportunity will land in Sinus Meridiani, a smooth plain where scientists have spotted deposits of a gray mineral called hematite. On Earth, it's a semiprecious stone and major source of iron ore. It also typically forms in the presence of water, which makes it a particularly tasty target for the rover science team.

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