The Space Shuttle Endeavour is seen with the International Space Station at the top of the frame as the crews aboard the two spacecrafts undock in this image from NASA TV, March 24, 2008. [Photo: NASA TV/Reuters]

The U.S. space shuttle Endeavour, with seven astronauts aboard, undocked from the International Space Station at 8:25 p.m. EDT Monday (0025 GMT Tuesday), beginning its journey back to Earth, NASA TV broadcasted.

Endeavour's crew and Expedition 16 at the station bid one another farewell in the afternoon with a flurry of hugs and hand-shakings.

"It's a strange feeling to want to see our families, but not want to leave a wonderful place," Endeavour Commander Dominic Gorie said to the station residents.

However, the undocking procedure was unexpectedly delayed about 30 minutes from the originally planned time because a solar array joint aboard the station was unsecured.

After the problem was solved, the shuttle finally departed from the space station when they flew over the Indian Ocean, reported the mission control center on the ground.

ISS flight engineer Garrett Reisman rang a bell aboard the station in a long-standing tradition for undocking spacecraft. ISS Commander Peggy Whitson appreciated the hard-working Endeavour guys, leaving a growing space station behind them.

After the physical separation, the shuttle began its slow loop around the station while the crewmembers will photograph the exterior of the station. When the fly-around finishes, Endeavour will head back to Earth in its full swing.

During the 12-day stay at the orbital outpost, Endeavour crew, along with the station partners, performed the record-setting five spacewalks, which are the most ever done in single shuttle mission visiting the station.

Spacewalkers devoted the first three spacewalks to assembling a Canadian-built robot, named Dextre, outside the station. The fourth spacewalk focused on testing a method for repairing damaged shuttle heat shield tiles, while the fifth involved stowing an inspection boom on the station.

In addition to the two-armed robot, Endeavour delivered the first component of Japan's first orbital laboratory Kibo. During their joint operation, the two groups of astronauts successfully attached Kibo's storage component to the planned place, making it run smoothly.

Endeavour got off the ground on March 11. After the shuttle arrived and linked up with the station, one of its crew members Garrett Reisman switched places with expedition 16 Flight Engineer Leopold Eyharts, who represents European Space Agency.

Eyharts is returning to Earth aboard Endeavour. If all goes well, Endeavour will land at the Kennedy Space Center in Florida on Wednesday night, according to NASA's mission schedule.