Astronauts have run into their first big glitch with the International Space Station?s brand-new room, one that may delay plans for opening its long-awaited observation deck.
An insulation cover for the $382 million module?s end cap doesn?t fit properly and is vital to protect the new Tranquility module once the window-lined observation deck there is moved to its final perch.
?When we remove a module and expose it to space, you want some kind of protection,? said space station flight director Bob Dempsey early Saturday.
The insulation is a round, multilayered fabric covering installed with buckles and four fold-down bars to lock it in place. Astronauts could not swing those bars fully into place because pieces of metal securing handrails and other tools in place in the dome-shaped window unit were in the way.
The observation deck, a $27.2 million addition, is known as the Cupola. It has six petal-like windows arranged around a round central pane that is the largest space window ever launched.
It arrived with the Tranquility module aboard the space shuttle Endeavour. They were installed earlier this week in a spacewalk and opened late Friday night.
Astronauts planned to move the observation deck next week to an Earth-facing spot on the bottom of Tranquility, where it would give astronauts a panoramic view of the planet below.
Dempsey said engineers are now considering whether to move the observation deck without the insulation cover on the end of Tranquility or to leave it place for the remainder of Endeavour?s mission and send a new fitted cover on the next shuttle flight, which will launch in mid-March.
The end of Tranquility wouldn?t be exposed for long, Dempsey said. A cone-shaped adapter will be moved to cover it after the observation deck is installed.
There is also a concern that the same obstruction preventing the insulation cover?s installation could interfere with the Cupola?s move to its final lookout perch.
Engineers are studying that possibility too, Dempsey said.
?When you have interference like this that you didn?t expect, there?s always that question in your mind that you have to go analyze,? he added.
The Tranquility module and observation deck, called the Cupola, are NASA's last major additions for the space station. They are attached to the left side of the station's central Unity node.
With them installed, the space station is now 98 percent complete and weighs nearly 800,000 pounds (362,873 kg). The $100 billion space station has been under construction since 1998 and is the result of cooperation by 16 different countries.
After opening the new room, astronauts swiftly got to work loading it with gear. It was dark and sometimes stuffy ? the module is not fully activated yet ? but the astronauts managed to move a bulky exercise machine inside and began outfitting the room for permanent use.
?It?s great to see it up here in space,? Endeavour astronaut Kathryn Hire said in a series of interviews televised on NASA TV. ?We?re filling it up very quickly.?
While engineers on Earth study the Cupola concerns, Endeavour?s six-astronaut crew and the five spaceflyers on the space station are gearing up for their mission?s second spacewalk.
Shuttle astronauts Robert Behnken and Nicholas Patrick are due venture outside the space station late Saturday night at 9:09 p.m. EST (0209 Sunday GMT) for a 6 1/2-hour spacewalk aimed primarily at hooking up the plumbing hoses for the Tranquility module?s cooling system.
The spacewalk is the second of three excursions needed to fully switch on the new space station room?s systems.
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SPACE.com is providing complete coverage of Endeavour's STS-130 mission to the International Space Station with Managing Editor Tariq Malik and Staff Writer Clara Moskowitz based in New York. Click here for live spacewalk coverage and shuttle mission updates and a link to NASA TV.