NASA bumps lunar 'bots for Endeavour launch

NASA is bumping its robotic mission to the moon in favor of a rescheduled Endeavour launch on Wednesday.

The US space agency said today the human-staffed excursion to the International Space Station will take priority June 17 over the launch of NASA's unmanned Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS).

The space-faring 'bots will have to cool their jets until June 18 at the earliest.

Endeavour's STS-127 mission blastoff was scrubbed Saturday morning when NASA discovered a potentially dangerous hydrogen leak in the vent line leading to the shuttle's external fuel tank. A similar problem grounded Discovery's STS-119 mission to the ISS in March.

"Our teams have been working very hard over the last couple days to get this piece of equipment fixed," said NASA Test Director Steve Payne during a Monday debriefing. "Endeavour is in good shape and the teams are excited to be back to working towards a launch on Wednesday morning."

With a queue of rockets now forming in Florida, NASA had to choose between hauling the final piece Japan's Kibo lab to the ISS, and the agency's first return to the lunar surface in a decade. Complicating the matter is the relatively short window of opportunity available for both.

Endeavour must fly by this weekend or wait until mid-July because the sun angle would overheat the shuttle while docked to the ISS.

NASA's two lunar probes also need to be launched by Saturday or wait until the end of this month for a second chance.

The LRO spacecraft is designed to scout for "safe and compelling lunar landing sites" while LCROSS looks for signs of water in a plume of debris caused by its Centaur rocket smashing into the moon.

NASA said it can maximize launch attempts by giving Endeavour the go on Wednesday. The Air Force will need a day to reconfigure the systems for its unmanned Atlas V rocket launching the probes. The lunar craft are scheduled to blastoff Thursday, with Saturday reserved as a backup. ®