Hydrogen Gas Leak Delays Shuttle Launch

NASA postpones its trip to the International Space Station by at least four days as the space agency seeks answers to a leak in the launch pad venting system. It's the second such leak in three months to delay NASA shuttle launches.

The seven-person crew of the space shuttle Endeavour never even suited up before NASA scrubbed a June 13 launch to the International Space Station due to a potentially dangerous hydrogen gas leak. NASA scratched the launch at 12:26 a.m. EDT, and the 16-day mission will be delayed until at least June 17.
That date, however, is already booked for the moon-bound launch of an Atlas V rocket carrying the LRO (Lunar Reconnaissance Orbiter) and the LCROSS (Lunar Crater Observation and Sensing Satellite). According to NASA, no decision has been made about which launch will have priority.
If Endeavour doesn't launch before June 20, the mission will be delayed until July 11 because the late June and early July sun angle on the ISS would create heat issues for Endeavour.
After calling off the launch, NASA began draining Endeavour's external fuel tank to begin an investigation of the leak. A hydrogen gas leak also delayed the March launch of Discovery by four days. NASA patched that leak at a vent line, but the space agency still hasn't determined the exact source of the leak.
Launch Director Mike Leinbach said the Endeavour leak made the risk of a launch pad explosion too high.
"There's no way we could have continued," he said at a news conference. "It's a commodity you just don't mess with."
Endeavour was scheduled to arrive at the ISS with a cargo bay full of work, including the final permanent components of the Japan Aerospace Exploration Agency's (JAXA's) Kibo laboratory complex, a literal "front porch" on the ISS for space-exposed science experiments. To store and transport the experiments that the exposed facility will accommodate, Endeavour is also carrying a storage area similar to the logistics module on the Kibo laboratory, but unpressurized.
"It's a real exciting mission. We are the last mission that is taking up Japanese hardware on a space shuttle ... really big pieces of equipment that we're going to go ahead and leave behind on the space station for construction," Endeavour Commander Mark Polansky said in a preflight interview.
NASA plans a June 16 media conference to update the mission status.