NASA announced that the US space shuttle Discovery undocked from the International Space Station at 5:32 a.m. EST.

"Thank you guys for the module and all your help," space station commander Peggy Whitson said.

During their 11-days stay at ISS the Discovery astronauts installed the new Italian- made Harmony module, a high-tech hallway and Tinker toy-like hub. It is a 23- by 14-foot passageway that will connect the U.S. segment of the station to the European and Japanese modules, to be installed later this year and early next year, respectively.

Harmony will provide air, electricity and water for the space station, as well as additional lodging for crew members.

During the third spacewalk, the crew installed the P6 truss and solar array pair in its permanent location outboard of the port truss. The fourth spacewalk was changed during the mission so that the crew could repair a torn solar array on the P6 truss.

After undocking, STS-120 Pilot George Zamka backed the orbiter about 400 feet from the station and performed a fly-around to allow crew members to collect video and imagery of the station in its new configuration. He completed the final separation engine burn at 7:15 a.m.

The crew will spend Tuesday preparing for landing. Discovery’s first landing opportunity is at 1:02 p.m. Wednesday at Kennedy Space Center, Fla.

The shuttle's home journey comes after a final and risky spacewalk by US astronauts Scott Parazynski and Doug Wheelock on the weekend to repair a damaged solar array which was vital for assuring sufficient electricity supplies for the ISS.