Updated

CAPE CANAVERAL, Florida -- The astronauts on NASA's next-to-last shuttle flight floated out of the International Space Station on Sunday and then closed the hatch behind them, after one final round of warm wishes and embraces.

All that remained was space shuttle Endeavour's undocking late Sunday night and its two-day trip home.

Shuttle commander Mark Kelly said the 1 1/2 weeks of joint flight went well. He was the last to leave the space station, lingering for a few seconds with the three space station residents.

"We're looking forward to getting home," Kelly said, "and we're going to leave these guys to some peace and quiet and not disturb their space station any more."

"It was really great seeing you guys," said station resident Ronald Garan Jr. "We were just in awe of your finely oiled machine."

The station's skipper, Russian Andrey Borisenko, wished the six shuttle astronauts a "soft landing."

Endeavour will return to Florida in the pre-dawn hours of Wednesday, never to fly in space again. The shuttle will be retired to a museum in California following the 16-day mission, its 25th.

On its final journey, Endeavour delivered a $2 billion cosmic ray detector that will remain on the space station for the next decade.

The Alpha Magnetic Spectrometer already is collecting 25 million to 40 million cosmic particles a day worthy of analysis. It's searching for antimatter and dark matter, and scientists hope the findings will shed light on the origin of the universe.

Kelly and his crew also provided the space station with a platform full of spare parts and an extension boom for future repair work. The boom, installed Friday on the fourth spacewalk of the mission, marked the completion of the U.S. portion of the space station.

The astronauts also worked on some of the critical life-support systems inside, in an effort to leave the orbiting outpost in the best possible shape for the shuttle-less years ahead.

Astronauts Mike Fincke and Gregory Chamitoff -- who spent months living on the space station in years past -- pretended they didn't want to leave Sunday morning. They were dragged into the shuttle by their crewmates. Garan joined in on the joke, waving goodbye as if he were heading out aboard Endeavour as well. He's just two months into his five-month station stay.

All told, the hatches between the two spacecraft were open 11 days.

Only one more shuttle flight remains for NASA.

Atlantis will blast off July 8 with a load of space station supplies to close out the 30-year shuttle program.

Kelly, meanwhile, will now have to go without daily calls to his wife, Rep. Gabrielle Giffords. He used the space station's Internet phone to keep abreast of her condition, and NASA even arranged a videoconference between the two.

Giffords is undergoing rehab in Houston for a gunshot wound to the head. She was critically wounded Jan. 8 in Tucson, Ariz., during a political event. She attended Kelly's launch May 16 and, two days later, underwent skull reconstruction.

She is not expected to be at Kennedy Space Center for Endeavour's homecoming given the inconvenient hour: 2:35 a.m.DT