During their 10-day mission, the six-member crew is scheduled to conduct three spacewalks. The tasks include attaching the cargo pallets with their spare components the outside of the space station. They'll also continue with maintenance and construction-related jobs, such as installing a wireless video system that will relay video from spacewalkers' helmet-cameras to crewmembers inside the station as well as controllers on the ground.
The smaller crew size, shortened mission length, and the type of cargo highlight how close the space station is to the end of its construction phase, and how close the shuttle program is to its swan song. The last station module scheduled for delivery, "Tranquility," is set to launch in February. It will house a COLBERT treadmill and sport a multi-window cupola. The final shuttle launch currently is scheduled for September 2010.
Recent missions have kept the shuttle docked at the station for 10 or 11 days, and astronauts have conducted four or five spacewalks. From that perspective, "it looks like we're kind of slacking off a little bit now," acknowledges Michael Moses, the launch-integration manager for the shuttle program and chairman of the mission management team. But those missions, he adds, were anything but normal.
"We're a victim of our own success. We make the five-EVA missions look real easy, so a three EVA mission must be a piece of cake," Mr. Moses says, referring to extra vehicular activities or spacewalks.
Still, he adds, "This is an extremely important mission."
Between now and the end of the program, the National Aeronautics and Space Administration (NASA) will be ferrying as much spare hardware as the shuttles can carry to ensure that the space station can operate through 2015.
"We're cautiously optimistic that we can even get to 2020 with the spares we'll have pre-positioned" by the time the shuttle program ends, says Michael Suffredini, NASA's International Space Station manager.
To do that, mission planners are shrinking the size of the shuttle crews and shortening the length of the missions where they can. This reduces the amount of weight at launch taken up by food, clothing, and other shuttle "consumables" needed to support a seven-person crew over a longer period of time. That capacity can be given over to additional spares the station will need.
Indeed, when Atlantis returns later this month, it will bring back Nicole Stott, who is winding up a nearly three-month tour of duty as a flight engineer aboard the station. After she returns, the shuttle no longer will be used to help rotate station crews. That duty will fall exclusively to the Russians until the US can build and field a new rocket for ferrying astronauts to low-Earth orbit.
The Ares 1-X, a test version of the shuttle replacement NASA plans to build, underwent a largely successful trial flight last month.
Over the coming months, an increasing amount of cargo will aim to bolster the station's research capabilities, Mr. Suffredini says. Even the pallets bearing the spare components have been designed to hold experiments scientists plan to conduct outside the station.
"Even though we have a little more assembly left to do, we're starting to focus on the use of the ISS," he says.
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