CAPE CANAVERAL, Florida (Reuters) - U.S. space shuttle Endeavour blasted off on Monday to deliver a potentially revolutionary physics experiment to the International Space Station on the next-to-last flight in NASA's shuttle program.
Spacecraft Endeavour's 25th and final voyage was expected to reach the orbital outpost on Wednesday. NASA plans one more mission to the station, using the sister shuttle Atlantis, in July, before phasing out the shuttle program this summer.
With six veteran astronauts strapped inside, Endeavour roared off its seaside launch pad at 8:56 a.m. (1256 GMT) when Earth rotated into position to optimally align the shuttle with the space station flying 220 miles above the planet.
The Endeavour mission is being led by Mark Kelly, a four-time shuttle veteran who is married to convalescent U.S. Representative Gabrielle Giffords.
The Arizona Democrat is recovering from a January 8 assassination attempt that killed six people and injured 12 others. She was at Kennedy Space Center to watch Endeavour's launch.
The shuttle carries the $2 billion Alpha Magnetic Spectrometer particle detector, which is designed to analyze cosmic rays for fingerprints of dark matter, antimatter and other phenomena undetectable by traditional telescopes.
The instrument, built by a consortium of 60 research agencies in 16 countries, is expected to sift through 25,000 cosmic ray hits a second and operate for at least the next 10 years while attached to the outside of the space station.
The shuttle also carries a pallet of spare parts to tide over the station after the shuttle program ends this summer.
The last shuttle flight by Atlantis, slated to launch in July, will deliver a year's worth of supplies to the station.
Endeavour is due back on June 1.
(Editing by Kevin Gray, Pascal Fletcher and Eric Beech)