Space shuttle Discovery and its seven astronauts pulled away from the international space station on Tuesday and headed home, leaving tons of fresh supplies behind as well as a new face.

The shuttle is due back on Earth on Thursday.

Discovery undocked as the two spacecraft soared 220 miles above China. Pilot Kevin Ford guided the shuttle in a lap around the station, essentially for picture-taking.

"Those were great views of that magnificent spaceship that just flew under us," said space station astronaut Michael Barratt. "We were all glued to the windows."

Discovery's departure ended nearly nine days of linked flight in which more than 18,000 pounds of equipment and experiments were dropped off. Astronaut Nicole Stott took up residence aboard the space station, replacing Timothy Kopra, homeward bound after being off the planet for nearly two months.

Kopra should have stayed longer at the orbiting complex, but had his mission cut short by launch delays to his shuttle ride up. Tuesday marked his 55th day in space.

Despite his abbreviated stay, Kopra was eager to be reunited with his wife and two children, and said he was looking forward to a sip of beer.

Also returning aboard Discovery: Buzz Lightyear. The 12-inch action figure spent 15 months at the space station as part of a NASA educational program. The doll will take part in a tickertape parade at Walt Disney World early next month.

Another piece of pop culture, though, remained on board the space station: a treadmill named after Comedy Central's Stephen Colbert.

Colbert had campaigned for naming rights to a yet-to-be-launched space station room, but NASA went with Tranquility for that and the comedian had to settle for the exercise machine that flew up on Discovery. The $5 million treadmill won't be assembled until later this month.

Six astronauts were left behind on the space station to continue their own lengthy missions. Stott, the newest occupant, will remain on board until November.

Mission Control, meanwhile, determined that the space station will not need to move out of the way of a piece of space junk that will pass within roughly 45 miles early Wednesday. It's a fragment from a Chinese satellite that was blasted by a missile two years ago.

It won't be long before another spacecraft drops by. Japan's brand new cargo ship will be launched Thursday and hook up to the space station one week later. Then at the beginning of October, a Russian Soyuz spacecraft will arrive with a fresh station crew and a billionaire tourist, Cirque du Soleil founder Guy Laliberte.

The space station is now 84 percent complete with a mass of more than 710,000 pounds. Six shuttle flights remain to wrap up construction. Atlantis is up next in November with a load of big spare parts.

NASA hopes to finish the station and fly the shuttle for the last time by the end of 2010 or early 2011. The future of human spaceflight, however, is unclear. A White House panel of independent space experts said in a report Tuesday that NASA cannot afford to return astronauts to the moon by 2020 as envisioned.