Troubles parallel ambitions in NASA Mars project

— -- NASA's new Mars rover aims high. It's bigger, more powerful and more sophisticated than any other robotic vehicle that has landed on another planet. It will try to answer a big question: Has life existed elsewhere in the solar system?

Its very ambition has gotten the rover in trouble. Thanks to a mix of technological setbacks and engineering misjudgments, the rover's epic scale is matched by epic problems. Its story offers a cautionary tale as NASA plans to devote large chunks of its science budget in coming years to grand "flagship" missions, including a spacecraft to return Mars rocks to Earth and another that would visit a moon of Jupiter or Saturn.

The new rover, known as the Mars Science Laboratory, is $235 million, or 24%, over budget. Work on it has run so late that engineers are racing to prepare the rover for its blastoff in 2009. After that, the next good launch window, when Mars and the Earth are closest, is in 2011.

"They aimed high, and they got burned," says Arizona State University's Phil Christensen, a Mars scientist who helped review NASA's Mars program.

To make up for Mars Lab's ballooning cost, $1.2 billion, NASA has had to raid the coffers of other science projects.

Last month, the Mars rover Spirit, which has roamed the Red Planet since 2004, was threatened with being turned off to help pay for Mars Lab. After word spread, NASA rescinded cuts to Spirit and twin rover Opportunity.

'Pushing the envelope'

Spirit and Opportunity were a triumph for NASA, but next to Mars Lab, they'll look crude. Their job was to look for water. Their successor has a tougher task: to search for the molecules that are precursors to life and for evidence of microbes at work.

That requires a big machine that relies on nuclear power rather than the current rovers' solar panels. Mars Lab will carry a full chemistry workshop and a robotic drill arm for gathering rock samples.

Mars Lab, conceived in 2000 and given formal approval in 2006, "is the most challenging planetary mission that's ever been flown," says Doug McCuistion, head of NASA's Mars program. "We're pushing the envelope in a number of areas, and it just kind of built up."