HOUSTON--The Endeavour astronauts cranked open aluminum shutters protecting the windows in the space station's new observation deck early Wednesday, giving the crew inside an "absolutely incredible" view of the Earth 220 miles below.
During the shuttle mission's third and final spacewalk, Robert Behnken and Nicholas Patrick removed insulation blankets from the cupola's seven windows late Tuesday and unbolted launch locks holding the aluminum shutters in place.
Astronauts Terry Virts and Kay Hire, standing by inside the cupola, then were cleared to crank open the shutters one at a time to test the deployment mechanisms, starting with the module's large central window.
"Well, as expected, the view from window seven is absolutely spectacular," Station Commander Jeffrey Williams marveled. "This has to be the largest window on board and when we have the others around it open, it'll give us a view of the entire globe. Absolutely incredible."
Later, all seven shutters were opened at the same time and television views from inside the station showed Williams, wielding a camera with a large telephoto lens, floating in the middle of the cupola with the brilliant Earth below.
"I don't think space station's ever going to be the same after this," said astronaut Stephen Robinson, the spacewalk coordinator.
Earlier, Behnken and Patrick activated a second ammonia coolant loop for the new Tranquility module delivered by Endeavour, removed a no-longer-needed keep-alive heater cable and connected power and data cables to a pressurized docking port on Tranquility's outboard hatch.
They then made their way to the cupola to remove the insulation and launch locks. When they returned to the Quest airlock to wrap up a five-hour 48-minute excursion, Hire congratulated them, saying "great job raising the curtains on a bay window to the world."
"Thank you, Kay. It was fun," Patrick replied. "I look forward to the view from the inside."
The cupola is intended to provide panoramic views for Earth observation and to serve as a robot arm work station, giving arm operators direct views of approaching cargo ships and maintenance sites. A robotics work station, one of two on board the station, will be moved into the cupola Thursday.
"Wow! What a spacewalk and what a view we got today," said lead Flight Director Bob Dempsey. "Truly a window of opportunity was opened on the world today.
"Sitting in my chair in mission control looking out at the view was just spectacular. And the astronauts, who are accustomed to views that you and I can't really describe, were moved to tears when they looked out the windows of the cupola for the first time."
Built in Italy by Thales Alenia Space, the cupola weighs 1.6 tons, featuring six trapezoidal side windows and a 31.5-inch circular top window, the largest ever launched into space. Each window features a protective "scratch" pane on the interior side, two inch-thick pressure panes and a debris pane on the outside to protect against space debris impacts.
When not in use, the windows will be covered by the aluminum shutters, which are manually cranked open and closed by the astronauts.
The greatest threat from a debris standpoint is from the front, in the direction of the station's 5-mile-per-second velocity. Shutters on the forward-facing windows typically will remain closed unless visibility in that direction is needed. Trailing windows can remain open for longer periods.
"We do have a very long flight rule that deals with the operations of this particular set of equipment," Dempsey said. "The two most major concerns of operating the shutters are thermal and micrometeoroid debris...The debris concern, obviously, is more severe.
"Even though they're reinforced to prevent anything happening to the crew, we want to keep them in good pristine condition so...the crew will have good views. This will be used for not only Earth observations, but for things like capturing, with the robotic arm, upcoming visiting vehicles."
Endeavour's mission was extended one day to give the astronauts time to repair and test the station's urine recycling system and to move life support system racks into Tranquility that until now have been housed elsewhere. With the addition of Tranquility and the cupola, the International Space Station is more than 98 percent complete.
If all goes well, hatches between Endeavour and the station will be closed early Friday and the shuttle will undock after the crew wakes up that night. Landing back here at the Kennedy Space Center is expected around 9:20 p.m. CST Sunday.