Discovery's final mission stalls. Photo Credit/NASA TV
Efforts by NASA to launch the shuttle Discovery from the Kennedy Space Center on Friday with a crew of six astronauts on her 39th and final mission have been postponed until no earlier than Nov. 30 because of a substantial launch pad hydrogen leak.
Nov. 30 marks the start of a launching period that extends through Dec. 5.
This current launch period, which opened on Nov. 1 extends through Sunday. Initially, NASA’s Mission Management Team looked toward a bid to launch on Monday, and shorten the Discovery crew’s stay at the space station. However, managers determined that a lack of rapid access to the launch pad to pinpoint the source of the potentially dangerous hydrogen leak and a second issue, a seven inch crack in the insulating foam on the shuttle’s external tank, diminished the prospects for success.
Between Nov. 8 and Nov. 30 the solar heating on the orbital plane of the space station exceeds the capabilites of the shuttle’s thermal control system.
Plans to begin the mission between Nov. 30 and Dec. 5 are considered tentative, said Mike Moses, who chairs NASA’s pre-launch Mission Management Team.
The period is sandwiched between long standing plans for three of the space station’s six member crew to return to Earth. aboard a Russian Soyuz capsule. Three new U. S. and Russian crew members are slated to lift off for the station in mid- December aboard a second Soyuz spacecraft
Discovery commander Steve Lindsey and his crew have trained to deliver and equip the station with an equipment storage module and an external spare parts platform. The shuttle is also carrying Robonaut 2, a humanoid robot, and 6,500 pounds of other research gear and supplies.
Friday’s hydrogen leak was substantial and surfaced about two hours after ground teams began to load Discovery’s external fuel tank with chilled liquid hydrogen and oxygen propellants.
“We concluded from a safety perspective we were done for the day,” said NASA launch director Mike Leinbach.
The leak rate exceeded ground safety levels as well as the Launch Commit Criteria, he said.
Discovery’s mission is one of two and possibly three flights remaining before the shuttle program retires.
Endeavour, assigned to the final scheduled mission, is tentatively slated to lift off on Feb. 27 with the Alpha Magnetic Spectrometer, an external astronomical observatory designed for the space station.
NASA would like to fly Atlantis on a final “final” mission in mid-2011. While Congress and the White House have authorized the Atlantis flight, the funding has not been appropriated.
Earlier this week, efforts to launch Discovery were postponed by stormy weather and the resolution of a voltage problem with a main engine computer.