It has been a special voyage for the entire crew, and especially so for Kelly, whose wife, U.S. Rep. Gabrielle Giffords, is still recovering from a gunshot wound to the head after the assassination attempt she survived in Tucson, Ariz., almost five months ago.
Kelly almost gave up his final opportunity to fly in space, but was finally persuaded his wife was in good hands and would want him to go. She underwent a successful cranioplasty surgery in Houston two weeks ago, after his launch, to replace bone that was lost after the shooting.
"I think it was the right decision. She was ready for the surgery," Kelly said.
NASA arranged for a videoconference between Giffords and Kelly, so they would be able to see each other during Endeavour's mission. There is also an Internet phone on the space station, and astronauts in orbit have access to email.
Speaking with ABC News in a crew interview from space, Kelly also shared some new good news about Giffords' progress.
"She'll be doing rehab for some continuing period of time," he said. "But at some point pretty soon she'll become an outpatient. So we're really looking forward to that. And it's all really encouraging."
After Endeavor lands at the Kennedy Space Center in Florida Wednesday, there will be only one more shuttle flight: Atlantis is currently scheduled for launch July 8. After Endeavour lands, it will be "safed" by engineers -- engines and explosive bolts will be removed, and traces of toxic fuel will be cleared from its plumbing. It will ultimately go on display in a Los Angeles museum.
What's next for America's astronaut program? That's not clear. The Obama administration has talked about having private companies launch astronauts to the station in yet-to-be-completed spacecraft, and NASA has been asked to make plans for trips to asteroids and, eventually, Mars. But all that is years away, and space people already talk wistfully of the space shuttle era as its end approaches.