NASA: Space shuttle launch no earlier than May 16

The space shuttle Endeavour, whose launch was scrubbed last week when a heater malfunctioned, will lift off on its final mission no sooner than May 16, NASA announced Friday.

U.S. Rep. Gabrielle Giffords will return to Florida to see her husband command the rescheduled launch, her spokesman said.

The earliest launch could be at 8:56 a.m. EDT in 10 days, the space agency said.

Senior managers were to meet Friday morning to review repairs to the shuttle, NASA said on Twitter.

Endeavour is scheduled to be commanded by Capt. Mark Kelly, the husband of U.S. Rep. Gabrielle Giffords.

Giffords is recovering from a shot to the head in what authorities charge was a Jan. 8 assassination attempt. Six were killed and 13 wounded, including the congresswoman, in the mass shooting at a constituent meet-and-greet.

Giffords who had traveled to Florida to watch her husband, Capt. Mark Kelly, command Endeavour on its final mission, returned to a Houston rehab center when the launch was delayed.

The congresswoman will return to Florida to watch the rescheduled launch, said spokesman C.J. Karamargin on Friday.

Crew members also flew to Houston on Sunday morning, they said on Twitter.

The crew will "stay in quarantine back in Houston," a NASA official said.

A failed heater in a hydraulic system forced NASA to cancel an April 29 launch.

"Based on the amount of time needed to do the fix, a new shuttle launch attempt will not happen before the end of the week, at the soonest," NASA tweeted last Sunday.

The launch was scrubbed after the heaters on one of Endeavour's power units failed about four hours before liftoff.

"There was no point continuing with the countdown," said launch commentator George Diller. "The external tank has to be drained to be able to do some electrical testing."

The heaters on "the system we use to generate hydraulic power" failed to come on during testing, said Mike Moses, the launch integration manager for space shuttle program, at a press conference.

Crew members, including Kelly, were on the way to the launch pad when NASA decided to postpone the flight.

The 134th space shuttle mission is to be the next to last flight for the program.

Endeavour will deliver the Alpha Magnetic Spectrometer, a device built to search the universe for dark matter and antimatter, to the International Space Station.

The mission is to include the last-ever scheduled spacewalk by a shuttle crew.

Launch delayed before

Just one other shuttle mission remains, a summer space flight by Atlantis scheduled for June 28. That mission could be pushed back if the launch of Endeavour continues to be scrubbed.

The Endeavour launch was first delayed from April 19 because Russia plans to send an unmanned cargo rocket to the International Space Station on April 27. NASA did not want the shuttle docked at the space station when the other ship arrived.

Giffords, a member of the House Committee on Science, Space and Technology, attended Kelly's most recent launch when he commanded the space shuttle Discovery in 2008.

Kelly's upcoming mission is scheduled to be the last flight for Endeavour and the next-to-last space shuttle flight before the fleet is retired later this year. Shuttle Atlantis will blast off on the final shuttle mission in July.