The U.S. space shuttle Discovery has undocked from the international space station Alpha, leaving behind a new crew for the outpost, and ferrying the old one back home.
The two U.S./Russian space station teams exchanged final hugs and handshakes, after a week together in orbit.
The outgoing Russian commander, Yuri Usachev, thanked everyone who had helped him and his two U.S. crewmates, Susan Helms and Jim Voss in their more than five months in orbit. "It's time to say goodbye station, good luck new crew, and we'll see you soon," he said.
Mr. Usachev's successor, Frank Culbertson, expressed his gratitude to the old crew just before the hatches between the station and Discovery closed for the last time on this mission. "Yuri, Jim, and Susan, I know it's a tough day. I know it's hard to say good-bye, but we really, really are proud of all you have done," Mr. Culbertson said. " We will do our best to keep up the good tradition you have started, and to maintain just as high a standard of excellence, if we can."
The former station crew is due to land on Earth Wednesday. Mr. Culbertson and Russian Cosmonauts Vladimir Dezhurov and Mikhail Tyurin will stay aboard the station until the shuttle Endeavour exchanges them with another crew in early December.
This crew rotation was the main objective of Discovery's visit. But the shuttle also re-supplied the outpost for the four-month sojourn of its new crew, and two shuttle astronauts went on spacewalks to add new hardware to Alpha. A U.S. space agency official in charge of station operations, Jim Van Laak says the mission was typical of those to come.
"One of the key things that I would point out about this mission is that, it was a real demonstration of what the mature phase of ISS-shuttle operations is going to look like, a very good indicator of what we have to look forward to for the next few years, and we're very pleased about that," he said.
Staying behind on the station with its new crew are two plaques that had been on the now defunct Russian Mir space station. Commander Culbertson carried them up on Discovery.
"I have brought with me a couple of mementos that flew on board the Mir station that I wanted to bring to the station, to spend a little bit of time here in space, to tie the two stations together," he said.
The plaques have the signatures of all the astronauts and cosmonauts who flew in the first phase of the international space station program, which Mr. Culbertson managed before returning to astronaut duty. That phase occurred before station assembly, when the U.S. and Russian space programs exchanged crewmembers aboard Mir and shuttles in the mid-1990s, to learn how to work together in orbit, after decades of Cold War competition.