The U.S. space shuttle Discovery has docked at the International Space Station on its final voyage into outer space.

The shuttle paused on its way to the orbiting outpost Saturday to perform a 360 degree backflip, a maneuver that allows astronauts on the space station to take pictures of the shuttle's heat shield to inspect it for possible damage.

In addition to a crew of six, Discovery is also carrying a human-like robot designed to assist astronauts, and a multi-purpose storage unit.

Discovery, first launched in 1984, has flown on 38 missions, more than any other shuttle in the NASA fleet.  It carried the Hubble Space Telescope into orbit in 1990, and was the first shuttle to travel to Russia's Mir Space Station.

The mission was originally scheduled for late last year, but was postponed because of a hydrogen leak and cracks in the external fuel tank.

The United States is ending its space shuttle program 30 years after the first launch.

The shuttle Endeavor still has one final voyage, set for April 19 and Atlantis may have one more after that.