Two astronauts have wrapped up their work outside the orbiting International Space Station to help install a new live-in module.
Spacewalkers Scott Parazynski and Douglas Wheelock were on the job at 6:02 a.m. ET on Friday, just as the station passed over South America. They wrapped up at 12:16 p.m.
NASA reported on its website that the Harmony compartment module had been successfully placed in a temporary location on the station.
"Now the crews that are hot on our heels have a place to come," Parazynski said.
Once fully installed, Harmony will be the docking port for European and Japanese laboratories scheduled for delivery over the next three shuttle flights.
The model, made in Italy, weights about 16 tonnes and is about the size of a school bus. Italian astronaut Paolo Nespoli co-ordinated the installation from inside the space station.
The two space-walkers worked in tandem with astronauts in the space station who controlled the Canadarm2 to transfer the compartment from the payload bay of the space shuttle Discovery.
The task is considered to be one of the most challenging construction tasks carried out at the space station to date.
"It's going to be a very interesting day. A lot of folks have been looking forward to this for a long time," John Shannon, chairman of NASA's mission management team, said earlier, referring to Harmony's installation.
The first task, however, was removing a broken antenna, which will be taken back to Earth for repair.
The Canadarm2 transported Wheelock to the antenna's location for removal.
"Thanks for the ride," he told astronauts Daniel Tani and Stephanie Wilson, the robotic arm's operators.
NASA has four more spacewalks scheduled. Parazynski is to take part in three of them. This was Wheelock's first time in space.
Another task for the 10 shuttle and space station astronauts is examining Discovery for any possible damage suffered during Tuesday's liftoff.
However, engineers haven't detected any significant problem with the shuttle's thermal shield.
Although several hours had been set aside on Saturday for a detailed examination of any problem areas, Shannon said that probably wouldn't be necessary.
In 2003, a piece of foam on the Columbia shuttle's external fuel tank broke free during re-entry.
The foam damaged the heat tiles. Columbia broke up on re-entry, and all seven astronauts aboard died.
With files from The Associated Press
