The space shuttle Discovery docked to the International Space Station as crews aboard the spacecraft prepare for undocking in this view from NASA TV December 19, 2006. [Photo: NASA TV/Reuters]

Space Shuttle Discovery and the seven crewmembers bade farewell to the International Space Station's Expedition 14 crew at 5:10 p.m. EST (2210 GMT) Tuesday and began the journey back to Earth, according to NASA TV.

The hatches between the station and shuttle Discovery closed at 2:42 p.m. EST (1942 GMT). "We are going to say a farewell to the Discovery crew," ISS commander Michael Lopez-Alegria said as the hatch was shut. "I think all of us will declare this mission successful."

Then the two crews conducted leak checks before Discovery undocked. Pilot Bill Oefelein will guide the shuttle through a partial fly-around of the space station before firing shuttle jets at 6:52 p.m. EST (2352 GMT) to begin the final separation from the station and the trip back home.

During the busy eight-day stay at the station, the crew continued the on-orbit construction of the station with the addition of a new truss segment during the first of four spacewalks. The next two spacewalks were devoted to the rewiring of the station's power system, leaving it in a permanent setup. A fourth spacewalk was added to allow the crew to retract solar arrays that had folded improperly.

Discovery also delivered a new crew member and more than two tons of equipment and supplies to the station. Almost two tons of items no longer needed on the station will return to Earth with the space shuttle.

This is NASA's third and final shuttle mission in 2006. Discovery is scheduled to land at 3:56 p.m. EST (2056 GMT) on Friday at Kennedy Space Center, Florida.