The problem with sensors and software that measure the amount of fuel being loaded into the rocket appeared with just minutes left until liftoff. Two days after bringing Discovery home, NASA rescheduled the launch for Friday morning.
The Mars Reconnaissance Orbiter was expected to spend at least four years circling Mars. The spacecraft is equipped with new tools designed to gather more data on the planet than all previous Martian missions combined.
The Mars Reconnaissance Orbiter is expected to collect information that will help NASA plan where to land two robotic explorers later this decade and possible future human exploration of the Red Planet.
The Phoenix Mars Scout, in search of organic chemicals, will be launched in 2007, and the Mars Science Laboratory will follow two years later.
"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 Pasadena, Calif. "Better to know what we can make on the surface of the planet."
Early morning thunderstorms delayed fueling of the rocket launching the orbiter and pushed back the time of the liftoff by at least an hour Thursday.
The two-ton orbiter, equipped with the largest telescopic camera ever sent to another planet, will provide unparalleled information on Mars' weather, climate and geology. The $720 million mission is also expected to help build on NASA's knowledge of the history of ice on the planet.
The planet is cold and dry with large caps of frozen water at its poles. But scientists think it was a wetter and possibly warmer place eons ago — conditions that might have been conducive to life. Scientists are also trying to determine if it could support future human outposts.
"With the subsurface of Mars, we've literally just scratched the surface and we're trying to probe, now, more than a couple of feet into it," Zurek said.
CBS News Correspondent Jerry Bowen reports that earthlings are thinking of using the same toxic stuff already blamed for global warming here to put some life back on Mars.