Space Shuttle Endeavour Cleared for May 16 Launch

NASA clears Endeavour for its final flight into space, bringing the shuttle one step closer to the end.

Officials at NASA announced that the space shuttle Endeavour's final flight into space is scheduled to launch the morning of Monday, May 16 on a 16-day mission to the International Space Station. The STS-134 crew is preparing to return Thursday to NASA's Kennedy Space Center in Florida. Endeavour's final launch will also mark the beginning of the end for an era of NASA; it will be the space agency's penultimate shuttle flight.

Space shuttle program launch integration manager Mike Moses and shuttle launch director Mike Leinbach announced the date at a news briefing Monday from Kennedy Space Center. They also discussed the progress of repairs since Endeavour's launch postponement on April 29.

A short in the heater circuit associated with Endeavour's hydraulic system resulted in the launch postponement. NASA technicians determined the most likely failure was inside a switchbox in the shuttle's aft compartment and associated electrical wiring connecting the switchbox to the heaters. The heater circuits prevent freezing of the fuel lines providing hydraulic power to steer the vehicle during ascent and entry, the space agency explained in a pre-launch release document.

The faulty box was replaced May 4. Since Friday, Kennedy technicians installed and tested new wiring that bypasses the suspect electrical wiring and confirmed the heater system is working properly. They also are completing retests of other systems powered by the switchbox and are closing out Endeavour's aft compartment.

In the meantime, technicians at Kennedy Space Center's Launch Pad 39A will continue closing out Endeavour's aft compartment and will retract the access arm to the external fuel tank today. Workers will complete installing and reconnecting the spacecraft's ordnance, and the team will continue preparing for the start of the countdown on Friday.

The crew members for space shuttle Endeavour's STS-134 mission are Commander Mark Kelly, Pilot Gregory H. Johnson and Mission Specialists Michael Fincke, Greg Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori. Kelly's wife, U.S. Representative Gabrielle Giffords (D-Ariz.), is expected to attend the launch of her husband's final mission to space, another milestone in the congresswoman's remarkable recovery after she was shot in the head during an assassination attempt this January.

During the 16-day mission, Endeavour and its crew will deliver the AMS (Alpha Magnetic Spectrometer) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre. The AMS is a particle physics detector designed to search for various types of unusual matter. The crew also will transfer Endeavour's orbiter boom sensor system to the ISS (International Space Station), where it could assist spacewalkers as an extension for the station's robotic arm.

Among Endeavour's missions was the first to include four spacewalks, and then the first to include five. Its STS-67 mission set a length record of almost two full days longer than any shuttle mission before it. Its airlock is the only one to have seen three spacewalkers exit through it for a single spacewalk. And in its cargo bay, the first two pieces of the ISS were joined together.