Mars or Bust

PLANETARY EXPLORATION

One of the largest spacecraft ever built to study Mars is set to begin its journey to the Red Planet, where it will look for water, good landing sites, and perhaps even lost spacecraft on the martian surface.

Slated for launch on Aug. 10, NASA's Mars Reconnaissance Orbiter (MRO) leaves previous spacecraft in the dust, team members say. Carrying a suite of instruments with much greater resolving power than earlier missions, MRO will be able to pick out 1-meter-sized boulders and narrow crevasses. Its radar camera will look beneath Mars's surface for possible water ice fields detected by the Mars Odyssey orbiter beginning in 2001.

It's possible that MRO could also spot NASA's lost Mars Polar Lander, which disappeared during touchdown in 1999. NASA is touting the project as a step toward President George W. Bush's goal of a manned mission to Mars.

MRO will spend seven months en route and six more months on a maneuver known as aerobraking, which will use the martian atmosphere to slow down the craft so it can enter a safe elliptical orbit. The craft will circle 255 to 320 km above the surface, about 100 km closer to the planet than any previous orbiter. Because its proximity risks contaminating Mars with microbes from Earth, MRO got an intensive cleaning before launch.

After two years of mapping, MRO will spend another two years serving as a relay for future Mars missions. Weighing 2,180 kg and costing more than $500 million, MRO is one of the heavier and more expensive spacecraft of recent design. It can send information back to Earth at an unprecedented rate of up to 5.6 megabits per second.

Previous missions "have been bringing back data through a straw. What we're doing is opening up a spigot," James Graf, MRO project manager at NASA's Jet Propulsion Laboratory, said at a briefing on July 21.