Six US astronauts are wrapping their mission at the International Space Station on Sunday before strapping themselves back into the shuttle Discovery, one day before setting back toward Earth, NASA said.
"Today, the 12 crew members will spend their final hours together, transfer some payload science samples from a freezer aboard the station to one on Discovery, say their goodbyes and close the hatches between the spacecraft," NASA said.
The six Americans who arrived aboard Discovery will say farewell to their ISS colleagues, who include two Americans, three Russians and one Italian.
During the mission, the astronauts installed a spare closet module on the ISS, completed some important repairs and delivered the first humanoid robot, though it will need more time to be assembled and made operational.
Discovery and its crew of astronauts are expected to land on Wednesday, March 9, after a 13-day mission that will mark the final space trip for the oldest and most traveled shuttle in the US space program.
The shuttle blasted off from Kennedy Space Center on February 24, on its last trip into orbit before it becomes the first of the three remaining US shuttles to become museum pieces later this year.
Endeavour is to lift off on April 19 followed by Atlantis on June 28, marking the official end of the US space shuttle program after 30 years.
Explore further: NASA extends Discovery shuttle mission by a day