Atlantis undocked early Tuesday from the International Space Station, marking the last shuttle departure from the orbiting laboratory, DPA reported.
The National Aeronautics and Space Agency NASA said the undocking took place at 2:28 am EDT (0628 GMT).
The ISS could not have been built without the heavy-lift capacity and large cargo bays of the fleet of US spacecraft.
Atlantis was to fly around the space station, snapping photos of the structure for review by ground crews, before leaving the laboratory behind.
The crew of the space shuttle Atlantis said their goodbyes before closing the hatch on Monday between the two craft.
US astronaut Ron Garan, who is living aboard the ISS with five other astronauts, said that the sealing of the hatch closed "a chapter in the history of our nation."
Atlantis brought more than 4 metric tons of cargo and spare parts to outfit the ISS for a year. The shuttle is the only spacecraft big enough to haul such heavy loads, though Russian, European and Japanese craft can still bring smaller, lighter cargo to the station.
"Thanks for leaving the ISS ready to go for the rest of the decade," Garan said.
The shuttle is due to land Thursday at the Kennedy Space Centre in Florida, marking the retirement of the 30-year-old shuttle fleet.