Mars Craft Launch Is Scrubbed

NASA postponed the liftoff of a spacecraft to Mars on Thursday after a glitch popped up in the computer software used for monitoring the fueling of the launch rocket.

The problem with sensors and software that measure the amount of fuel being loaded into the rocket appeared minutes before liftoff. NASA rescheduled the launch for today, three days after the shuttle Discovery returned to Earth.

Before the glitch, the only problem NASA faced was with an early morning thunderstorm that had delayed fueling. NASA officials couldn’t explain why sensors were reading “dry” when other data showed that the rocket was being filled with propellant.

“We weren’t quite sure what the cause was, and we felt we didn’t have enough time left ... to pursue it any further,” said Charles P. Dovale, NASA’s launch director.

The Mars Reconnaissance Orbiter, equipped with the largest telescopic camera ever sent to another planet, was expected to spend at least four years circling Mars, collecting information that would help NASA plan where to land two robotic explorers later this decade.

The two-ton orbiter will collect information on Mars’ weather, climate and geology. The $720-million mission also is expected to build knowledge of the history of the planet’s ice.

NASA hopes the information will aid possible future human exploration of the Red Planet.

“We don’t want to be hauling cement to Mars. That’s very expensive,” said project scientist Richard Zurek of the Jet Propulsion Laboratory in La Canada Flintridge. “Better to know what we can make on the surface of the planet.”

The craft is to join three other orbiting spacecraft when it arrives at the planet next March. Two NASA rovers launched in 2003, Spirit and Opportunity, also continue to roam the planet.