How the shuttle returns

They spent Tuesday testing flight control systems and packing away equipment after undocking from the International Space Station (ISS).

The shuttle is scheduled to land at 1302 local time (1802 GMT) on Wednesday.

The crew has delivered a new unit to the station, dropped off a new resident and undertaken a series of spacewalks.

Discovery pushed away from the outpost some 350km (220 miles) on Monday, above the Pacific Ocean.

Discovery pictured moments after undocking from the space station

"Discovery has physical separation," the shuttle's Commander Pam Melroy told Mission Control in Houston, Texas, as the orbiter moved back from the ISS.

"Thank you guys for the module and all your help," responded Peggy Whitson, the platform's commander.

Melroy and Whitson are the first women to simultaneously manage two spacecraft in the 50-year history of spaceflight.

They have overseen an eventful 11 days of co-operation at the station.

All change

Discovery brought up the Harmony module from Earth. It is a passageway that will link present and future science laboratories on the orbiting outpost.

Harmony was fitted to a temporary berth during one of the four spacewalks carried out during Discovery's stay. The module will be moved to its permanent position on the ISS structure next week.

During the third spacewalk, the crews repositioned a huge girder and solar array tower, only to find a rip in one of the wings of the energy-collecting unit.

With advice from ground engineers, the crews were able to work up a repair solution that involved dangling spacewalker Scott Parazynski out over the split panel to lash the damaged area together.

The repair meant the crews were able to fully deploy the solar array.

The dramatic spacewalk has allowed the US space agency to press on with plans to launch its Atlantis orbiter in December. This is the high-profile mission that will bring Europe's major contribution to the ISS - its Columbus laboratory.

This will be fitted to the Harmony node.

Once undocked, Discovery flew around the station to film its new configuration.

It will return to Earth with ISS resident Clayton Anderson, who has just finished a five-month tour on the platform. His place has been taken Daniel Tani, who came up with Discovery to start a two-month tour.