Space Shuttle Discovery has begun its long journey back home, carrying with it seven astronauts, including Timothy Kopra who was in the International Space Station for 55 days. The Shuttle is expected to reach Earth on Thursday.

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

The shuttle is due back on Earth on Thursday.

“We’re pretty fat with supplies now thanks to you,” called out space station astronaut Michael Barratt. “God speed you on your way home.”

Discovery undocked Tuesday as the two spacecraft soared 220 miles (350 kilometers) above China. Pilot Kevin Ford guided the shuttle in a lap around the station, essentially for picture-taking. Barratt said he and his station crewmates were glued to the windows watching “that magnificent spaceship that just flew under us.”

The shuttle astronauts quickly got started on an evening of surveying to check for any signs of micrometeorite damage and make sure their ship can return safely.

“The mission is far from complete for us, but we couldn’t be more pleased with how it’s gone,” said LeRoy Cain, chairman of the mission management team.

Discovery’s departure ended nearly nine days of linked flight in which more than 18,000 pounds (8,000 kilograms) 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 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.

Six astronauts stayed behind to continue their own lengthy missions. Stott, the newest station 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 (73 kilometers) 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 (322,000 kilograms). Si shuttle flights remain to wrap up construction. Atlantis is up net 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.