CAPE CANAVERAL, Fla. - After a poignant wake-up song requested by wounded Rep. Gabrielle Giffords for her astronaut husband, Endeavour and the two other space shuttles each marked milestones Tuesday for the retiring fleet.

In its first full workday in space for its last flight, Endeavour commander Mark Kelly and his crew conducted their final post-launch inspection for damage to the shuttle heat shield. Initial results "looked really good" for NASA's youngest shuttle, lead flight director Gary Horlacher said Tuesday.

Back at the Kennedy Space Center launch site, Atlantis, which will fly the final shuttle mission of the 30-year program, moved for the last time from its hangar to the massive Vehicle Assembly Building.

And Discovery, which flew its last mission in February, had some of its remaining toxic fuel drained from its smaller engines. It will go to the Smithsonian Air and Space Museum hangar outside of Dulles Airport near Washington.

In orbit, Endeavour was catching up to the International Space Station, aiming for a 6:16 a.m. Wednesday docking. Endeavour's day started with the traditional music wake-up call. The song: "Beautiful Day" by U2. It is the same song Giffords picked for Mark Kelly in 2006 when they were just dating.

But this time the message-of-hope lyrics seemed to have a special meaning given her recovery from a gunshot wound to the head Jan. 8 in Arizona. U2's Bono, who wrote the lyrics, has said the song is about a man who has lost everything but finds joy in what he still has.

This time the song was from Giffords and Kelly's two daughters. "It's good to be waking up in space again," Kelly radioed back to Earth. "I want to thank Gabby, Claudia, and Claire for that great wake-up song. It's always good to hear U2 and 'Beautiful Day' in space."

Giffords is expected to undergo surgery Wednesday to replace a piece of her skull removed by doctors after she was shot in January.

Most of Tuesday was spent looking for any damage to the shuttle's delicate heat shield from launch. On Monday, NASA officials said initial photographs showed only a couple of small bits of insulating foam came off the fuel tank during the crucial phase of liftoff. "The performance of the crew and the vehicle is outstanding at this point," NASA deputy shuttle program manager LeRoy Cain said Tuesday afternoon.

Endeavour is on a 16-day flight; its main mission is to attach to the space station a giant magnet that looks for antimatter and dark energy.