Astronauts ventured outside the International Space Station on Tuesday to put the finishing touches to an observation deck that gives residents a panoramic view of the Earth below.
On the last of three spacewalks planned for shuttle Endeavour's 14-day mission, astronauts Robert Behnken and Nicholas Patrick removed insulation that protected the viewport's seven windows during its trip into orbit.
Later, Patrick removed bolts that held the windows' shutters closed, and the circular cover on the dome-shaped observation deck's biggest window sprang open to reveal its first view of the Earth 200 miles (322 km) below.
"It will give us a view of the entire globe," said astronaut Jeff Williams from inside the cupola. "Absolutely incredible."
The $27 million, Italian-built port gives the station crew a commanding view of Earth and approaching cargo vessels.
Robot arm operators aboard the station now rely solely on camera views, with no direct view outside.
Major construction on the $100 billion orbital outpost is complete, and NASA has only four more shuttle missions planned to ferry spare parts and supplies to the station, a project of 16 nations that has been under construction since 1998.
After the shuttle missions end, travel to the space station will rely on Russian Soyuz spacecraft.
Endeavour and six astronauts blasted off on Feb. 8 for a 13-day construction mission. NASA added an extra day to the flight to help the station crew get the new modules ready for use.
Endeavour is due back at the Kennedy Space Center in Florida on Sunday.
NASA on Tuesday delayed launch of the next shuttle due at the station, Discovery, to April 5 from March 18 due to cold weather in Florida that has delayed launch preparations.