The astronauts aboard the orbiting shuttle and station closed the hatches between the linked spacecraft as Discovery got ready for its departure for Earth today.
Nasa was tracking another threatening piece of space debris, but did not think the orbiting outpost would have to steer clear.
The two crews – seven on the shuttle and six on the station – hugged and shook hands as they said goodbye before sealing the hatches. “Have a safe trip and have a safe landing, guys,” said the station’s skipper, Russian Gennady Padalka.
The 13 astronauts accomplished one last major job together before parting company.
A moving van holding a ton of rubbish and discarded equipment was moved back aboard Discovery, with the use of a hefty robot arm. The van was delivered by the shuttle, fully loaded with supplies, and moved onto the international space station one week ago.
The shuttle was expected to return to Earth on Thursday.
Meanwhile, the latest piece of threatening space junk is from a Chinese satellite blasted by a missile in a 2007 test. It was expected to fly near the space station early tomorrow.
Flight director Tony Ceccacci did not know the size of the fragment, but he noted that early projections put the closest approach at 15 miles. A massive piece of an old rocket passed less than a mile from the shuttle-station complex on Friday, but required no dodging.
The space station’s new resident, Nicole Stott, said she’s looking forward to gazing down at her home state of Florida and the rest of the planet over the next three months. She took up a watercolour kit to paint what she sees.
Ms Stott flew up on Discovery as the replacement for Timothy Kopra, who has been in orbit since mid-July.
As the shuttle crew prepared to leave, Mission Control asked them to do a final check to make certain a Buzz Lightyear action figure – the astronaut from the 1995 movie 'Toy Story' – was safely stowed on the shuttle.
The 12-inch toy has been at the international space station for more than a year.