Fuel leak thwarts 2nd launch try

June 17, 2009

NASA called off its second launch attempt of space shuttle Endeavour after another leak surfaced while the ship was being fueled for launch.

The next launch attempt won’t come until July 11.

“We were just not comfortable pressing on,” said shuttle launch director Mike Leinbach.

NASA had hoped to launch Endeavour last Saturday, but sensors detected dangerous levels of hydrogen gas escaping from a vent line and canceled the launch.  Engineers have not determined the root cause of the problem, but they had hoped that replacing suspect seals would do the trick.

Apparently, it didn’t. As the shuttle was being fueled for its second launch time, sensors again detected higher-than-allowable levels of hydrogen escaping from a venting line.

The line removes hydrogen that has turned from liquid to gas inside the shuttle's fuel tank. The gas is funneled to a flare stack away from the shuttle and safely incinerated.

Since hydrogen is so volatile, NASA has very tight safety restrictions on how much gas can be outside the shuttle.

NASA had just one shot at launching Endeavour this week. The agency wants to launch a moon probe to scout landing spots for a new venture to return astronauts to the lunar surface. The Eastern Test Range, which supports both shuttle and unmanned rocket launches from Kennedy Space Center and the adjacent Cape Canaveral Air Force Station can only support one type of rocket at a time and it takes about two days to reconfigure equipment for different launchers. The Lunar Reconnaissance Orbiter is slated to fly Friday.

Launching Endeavour between Sunday and July 10 is not an option because the angle of the sun would overheat the shuttle while it was docked at the space station.