U.S. space shuttle Atlantis undocked from the International Space Station (ISS) on Wednesday and is set to return to earth on Friday, NASA said.

NASA said Atlantis fired its thrusters twice, at 6:04 a.m. and 6:32 a.m. EST, after completing a full circle around the ISS.

"Atlantis is heading away from the station at about 1.5 feet per second, or about 4.5 miles per orbit," NASA said.

The 11-day Atlantis mission will return ISS crew member Nicole Stott to earth and is expected to be the final space shuttle crew rotation flight. Stott spent two and a half months on board the ISS.

When the mission completed, only five U.S. space shuttle flights will remain before the shuttle fleet is retired next year. Russian, European and Japanese space freighters will keep the ISS supplied until NASA deploys its new capsule-style Orion spacecraft.

MOSCOW, November 25 (RIA Novosti)