The U.S. space shuttle Atlantis is returning to Earth after spending a week at the International Space Station to deliver tons of spare parts to the orbiting outpost.

Atlantis undocked from the space station early Wednesday U.S. time.  It is due to land in the southeastern U.S. state of Florida on Friday.

Atlantis is bringing seven astronauts back to Earth, including Nicole Stott, who left the space station Tuesday after spending three months in orbit.

U.S. space agency NASA plans to retire its shuttle fleet next year after several more missions to upgrade the station.

Canadian astronaut Robert Thirsk said advancements made during the Atlantis mission will contribute to a bright future for space exploration.

Some information for this report provided by AFP, AP and Reuters.