By Chris Baltimore
HOUSTON (Reuters) - The crew of NASA's final space shuttle mission restocked the International Space Station with tons of supplies on Wednesday after waking to the music of Elton John.
In media interviews, Atlantis' crew reflected on the end of the 30-year shuttle program and the series of "lasts" that will end when the spacecraft returns to Earth for a planned landing on July 21.
"I think that after we get back down to the ground, after landing, that it's going to hit us really hard," said mission specialist Sandra Magnus. "I think we're all going to have a really hard time leaving the shuttle."
The shuttles are being retired to make way for a new generation of spacecraft that President Barack Obama says will put U.S. astronauts on an asteroid and then on to Mars.
Until then, the $100 billion space station will be NASA's foothold for manned spaceflight. U.S. astronauts will be ferried to the station and back aboard vintage Russian Soyuz capsules, at a cost of about $50 million per crewmember.
The shuttle fleet's crowning achievement was building the recently completed space station, a project of 16 nations that orbits 230 miles above the Earth.
"When it's all done we have the space station to show for it," Atlantis Commander Chris Ferguson said in a media interview. "It's been a great program."
Hoping to make full use of the station, NASA on Wednesday selected a Florida-backed nonprofit called the Center for the Advancement of Science in Space, or CASIS, to manage U.S. sections of the laboratory not being used by the space agency.
Atlantis' crew now faces the uninspiring but essential task of unpacking 9,403 pounds (4,265 kg) of spare equipment, supplies and food from an Italian-made cargo carrier hauled to the station in the shuttle's cargo bay.
"This is the great thing about spaceflight," said station flight engineer Mike Fossum, who completed a spacewalk on Tuesday to pack up a failed cooling pump for the return trip back to Earth.
"One day you are doing the most outrageous thing humans have ever done -- spacewalking. The next day, you are fixing toilets and packing boxes."
Earlier, Atlantis' crew woke to Elton John's "Rocket Man," a song about the loneliness and isolation that both celebrities and astronauts face.
"We wish you much success on your mission," Elton John said in a message. "A huge thank you to all the men and women at NASA who worked on the shuttle for the last three decades."
The crew's days have recently started with "Viva la Vida" by Coldplay, "Mr. Blue Sky" by Electric Light Orchestra and "Tubthumping" by Chumbawamba.
(Additional reporting by Irene Klotz; editing by Todd Eastham)