U.S. space shuttle Discovery homeward bound after leaving ISS

WASHINGTON, April 17 (Xinhua) -- The U.S. space shuttle Discovery undocked from the International Space Station on Saturday and headed for home after spending over 10 days at the orbiting outpost.

The space shuttle Discovery undocks from the International Space Station Saturday and heads home after a mission to install a new ammonia tank and deliver experiments and other gear. (Xinhua/Reuters Photo)

Before leaving, shuttle commander Alan Poindexter thanked the six station residents for their "utmost hospitality." The station's skipper, Oleg Kotov, said it was "really, really sad" to see the astronauts go.

Discovery delivered eight tons of supplies and equipment to the station, including spare bunks for the occupants of the space station, a large tank of ammonia coolant and seven racks filled with science experiments.

The mission conducted three spacewalks, with work including replacing an ammonia tank assembly, retrieving a Japanese experiment from the station's exterior, and switching out a rate gyro assembly on the station's truss structure.

Discovery's first landing opportunity at the Kennedy Space Center in Florida is at 8:48 a.m. (1248 GMT) on Monday, NASA said.

The Discovery flight was the 33rd shuttle mission to the station. Three flights to the station remain before the shuttles retire in 2010.

The International Space Station, a hundred billion dollar project begun in 1998 with the participation of 16 countries, is financed mainly by the United States.

In presenting his 2011 budget proposal in February, U.S. President Barack Obama announced that the space station will be maintained until at least 2020.