Live At KSC: NASA Starts Race To 5:40 AM Launch

LIVE IMAGES: The images above are from live video feeds at the Air Force 45th Space Wing Weather Squadron weather channel and the Launch Complex 39 area at Kennedy Space Center, where Endeavour and seven astronauts are scheduled to blast off at 5:40 a.m. on an International Space Station assembly mission. They will automatically refresh to the most up-the-minute image every 30 seconds, and you can click to enlarge them.

BLOGGER NOTE, 11:58 p.m.: N ASA engineers are loading liquid hydrogen and liquid oxygen into shuttle Endeavour's 15-story external tank and no problems have been encountered about a third of the way through the operation. NASA Launch Director Mike Leinbach will be on NASA TV in the next couple of minutes explaining how the launch team plans to make up for lost time and still launch as scheduled at 5:40 a.m. You can watch live here in The Flame Trench. Simply click the NASA TV box on the righthand side of the page to launch our NASA TV viewer and be sure to refresh this page for periodic updates.

NASA started fueling shuttle Endeavour after a lengthy weather delay late Tuesday and then launched a race against the countdown clock -- one aimed at a 5:40 a.m. liftoff on Wednesday.

Nasty summer storms continuously rolled across Florida's Space Coast earlier this evening, forcing NASA to delay a three-hour fuel-loading operation that had been scheduled to begin at 8:15 p.m.

Thunder rumbled, lightning crackled and rain drizzled in the area around launch pad 39A at Kennedy Space Center. But the skies finally started to clear around 10:30 p.m.

Facing a hard deadline to launch or delay until mid-July, NASA officials decided the weather had cleared enough to proceed with the loading of 526,000 gallons of highly flammable liquid hydrogen and liquid oxygen.

NASA safety rules prohibit fuel-loading operations if forecasters say there is greater than a 20 percent chance that lightning would come within five nautical miles of the launch pad during the first hour of tanking.

The launch director, with the concurrence of the safety director, may make an exception after consultation with the shuttle weather officer, the rules state.

NASA has never started a fuel-loading operation more than 90 minutes to two hours late, so it's unclear whether engineers can finish all countdown work in time to launch at 5:40 a.m.

Here's a look at the local weather radar and satellite photos that mission managers were examining during a meeting at 7:30 p.m.:



A postponement would have bumped the shuttle mission to mid-July to clear the way for the time-critical launch of a moon-mapping mission that is the first precursor to returning American astronauts to the moon by 2020.

The launch of an Atlas V rocket and NASA's Lunar Reconnaissance Orbiter likely will be pushed back to no earlier than Friday.

The orbiter is designed to scout sites for astronaut encampments and a piggyback payload will make a suicide dive into the south pole of the moon so a spacecraft following it can determine if there is water ice in the cloud created by the crash.

NASA will have opportunities to launch the mission Saturday before the agency would have to delay it until June 30. That's the next time Earth and the moon align properly for the trajectory the two satellites will be flying.

NASA tried to launch Endeavour last Saturday but a gaseous hydrogen leak during fuel-loading operations forced a scrub.

NASA is facing a period between June 21 through July 10 when sun angles on the International Space Station would be such that the outpost could not generate enough power, or dispel enough heat, to support a docked shuttle mission.

NASA officials said earlier this week that July 11 would be the next shuttle launch opportunity.