The countdown has begun for launching of space shuttle Endeavour on Monday at Kennedy Space Centre, with thousands of spectators including wounded US Republican Gabrielle Giffords arriving in Florida to watch her husband's last launch.
"Gabrielle landed safely in Florida. Smooth flight with STS 134 astronaut Greg Johnson's family. Thanks to NASA for great fly by of launch pad," sources said.
Giffords has been rehabilitating in Houston after suffering a gunshot wound during a shooting rampage in Tucson, Arizona. The suspect, 22-year-old Jared Lee Loughner, has pleaded not guilty. The rampage killed six and wounded Giffords and 12 others.
Giffords was present for Endeavour's first launch attempt in April, which was scrubbed because of an electrical problem.
Only President Barack Obama and his family, who came to Kennedy Space Centre to watch the last launch, will be missing as Endeavour attempts its 25th — and final — liftoff into low Earth orbit.
About 500,000 people are expected to gather along the Brevard County coast to watch what would be the penultimate launch in the space shuttle's 30-year, 134-mission history.
Everything was going on schedule on Friday, NASA test director Jeff Spaulding reported.
Around noon Sunday, the shuttle's metal protective scaffolding, called the Rotating Service Structure, was rolled away from Endeavour in preparation for liftoff.
Endeavour's six-man crew spent on Sunday reviewing their mission plans, meeting with mission managers, and resting up before going to bed at 4pm in preparation for their morning liftoff.
Six seasoned astronauts will be riding the space shuttle Endeavour when it blasts off to space one last time.
The crew will make a second attempt at launching after an earlier try two weeks ago was called off over a technical glitch.
Endeavour is slated for a 16-day sojourn to the International Space Station to deliver spare parts and a $2 billion astrophysics experiment called the Alpha Magnetic Spectrometer to the orbiting laboratory.
The STS-134 crew includes commander Mark Kelly, pilot Greg H Johnson and mission specialists Michael Fincke, Andrew Feustel, Greg Chamitoff and Italian astronaut Roberto Vittori.
Kelly, a veteran of three previous space shuttle missions, will serve as commander on Endeavour's STS-134 mission.