After five successful spacewalks, the seven-member crew of the US space shuttle Endeavour prepared Monday to undock from the International Space Station and begin their trip back to Earth.
Astronauts spent their final hours at the ISS wrapping up transfers of equipment and supplies between Endeavour and the station, and checking out the tools needed for undocking and subsequent activities, officials said.
The undocking is scheduled for 7:56 pm EDT (2356 GMT) and begin its journey back to Kennedy Space Center, Florida.
Looking back at the mission during a press conference late Sunday, Endeavour commander Dominic Gorie qualified it an all-around success.
"We've done awesome," Gorie pointed out. "Every spacewalk was a win, every robotic op (operation) was a win. We've got a couple more to go with the undocking and the landing, but we've got a great winning team."
Two astronauts from the Endeavour -- mission specialists Robert Behnken and Mike Foreman -- on Sunday attached a 50-foot sensory boom to the outside of the International Space Station.
Space station flight director Dana Weigel said the spacewalk, often referred to by National Aeronautics and Space Administration officials as an EVA, or an extra-vehicular activity, had set a new record.
"This was five EVAs, which was more than we've done on any station mission," the flight director pointed out.
Endeavour, whose mission at the ISS is the longest ever, is scheduled to return to Earth on Wednesday.
The spacewalkers also successfully installed an experiment on the outside of the European Space Agency's laboratory, which the astronauts had failed to complete during the third spacewalk on March 17.
They completed the walk by installing trunnion covers on the Japanese module and stowing tools in a toolbox before returning to the space station.
The Endeavour mission's main tasks were to install the first part of the Japanese Kibo lab, which will join similar facilities from the United States, Russia and the EU, whose Columbus lab was delivered to the ISS in February.
"At this moment, the people of Japan are very excited about the module," said Japan Aerospace Exploration Agency astronaut Takao Doi, who is to return to Earth on board Endeavour. "It is going to open up a new era for Japan in the space program."
He added that it remained to be seen how Japanese culture would adjust to the realities of ISS.
But in the meantime, "we like the food a lot," quipped space station commander Peggy Whitson.
European Space Agency astronaut Leopold Eyharts of France, who is returning to Earth after an about two-month stay on the ISS, said he was ready for the trip back home.
"I'm trying to exercise regularly, but I'm quite confident because a couple of months is not so much," Eyharts told reporters.
Astronauts have also assembled the Canadian-made Dextre robot, which is designed to undertake maintenance operations on the space station that until now required a human touch, and reduce the need for risky spacewalks.
The robot's human-like upper torso swivels at the waist, and its arms were designed with seven joints to provide it with maximum versatility. Umbilical connectors provide power and data connectivity.
Manipulated by joysticks inside the ISS or from ground control on Earth, the 1.56-tonne robot will conduct operations such as replacing small components on the station's exterior -- tasks which until now required a human touch.
Each of its "hands" has two retractable grippers that can grab equipment and tools. The hands also each carry a retractable motorised socket wrench, a camera and a light for viewing the work undertaken.
NASA wants to complete construction of the ISS by 2010, when its three-shuttle fleet is scheduled to be retired. (AFP)
US shuttle Endeavour prepares for return trip to Earth