CAPE CANAVERAL, Fla. – NASA scrubbed the launch of the shuttle Discovery Wednesday after a small cloud of explosive hydrogen gas leaked from the main fuel tank.
Space agency officials postponed the mission to the international space station until at least Sunday. The timing of the launch will depend on how quickly shuttle engineers can find the source of the leak and make repairs.
The flight, originally planned for 14 days, will deliver a $278 million solar panel assembly, completing the space station’s electrical generating system. But the flight now will be shortened and some of the four spacewalks will be canceled, said Mike Moses, who chairs NASA’s mission management team. Moses said the tentative plans are to try for a liftoff at 6:43 p.m. Sunday. The launch may be pushed back to Monday or Tuesday, he said.
‘We want to make sure we are not rushing,’ he said.
If the shuttle cannot lift off by Tuesday, NASA must delay the mission until April 7. That would give the Russians enough time to launch a Soyuz capsule carrying Russian Gennady Padalka and American Mike Barrett for prolonged tours.
The countdown was halted after sensors detected flammable concentrations of hydrogen gas. The gas was leaking from a venting system in the plumbing outside the shuttle’s external fuel tank. The hydrogen leak, which could have caused an explosion at liftoff, was detected as NASA neared the end of a three-hour operation to fill the fuel tank with 500,000 gallons of liquid hydrogen and oxygen rocket fuel.
Efforts to stop the leak were unsuccessful, said launch director Mike Leinbach.
The fueling operation was halted and the tank drained before the amount of leaked gas reached the danger point, Leinbach said.
Discovery’s seven astronauts were miles away in their Kennedy crew quarters. No personnel were on the launch pad.
If NASA makes repairs in time for a launch attempt Sunday, Discovery’s flight will be pared to 11 days and the number of spacewalks cut from four to three.
If the launch slips to Monday, the mission will be cut to 10 days with just one or two spacewalks.
If Discovery goes into space on Tuesday, NASA is looking at a nine-day mission and a single spacewalk to equip the station with the new solar power assembly.
The new power module will generate enough electricity to double the space station’s crew to six by May.
The weather, nearly perfect Wednesday, remains favorable for Discovery’s launch through Monday.