CAPE CANAVERAL, Fla. - The space shuttle Discovery is set to ferry up
the last big American-made piece of the International Space Station after a
decade of construction when it launches Wednesday night.
Discovery is poised
to lift off at 9:20 p.m. EDT (0120 March 12 GMT) from a seaside launch pad
here at NASA's Kennedy Space Center carrying seven astronauts and the last
segment of the station's backbone-like main truss, along with a final set of power-generating
solar arrays. The elements are the last major U.S.-built contribution to
the now 10-year-old space station, which will be 81 percent complete by the end
of Discovery's STS-119 mission.
The new truss, massive girder called Starboard-6 (S6), weighs about 30,000
pounds (13,607 kg), and will push the station's total weight to nearly 1
million pounds (453,592 kg).
When complete, the space station's complete 11-segment main truss will
span a distance of 310 feet (94 meters), longer than a U.S. football field. The
station can already be seen by the naked eye from Earth as a bright, rapidly
moving object.
The $298 million S6 segment was assembled for NASA by Boeing. It is 45
feet (13.7 meters) long with two wing-like solar arrays that will have a
wingspan of nearly 240 feet (73 meters) when fully unfurled. The new solar
wings are the station's fourth set of U.S. solar arrays and will complete its
American-built power grid.
"This is a very special moment to see our last Boeing-designed-and-built
truss go into orbit," said Chuck Hardison, Boeing CAPPS mission management
and operations director. "The space station now is a massive orbiting
item, and something the United States and its international partners should be
very proud of."
NASA plans to launch Discovery's STS-119 flight and at least eight more shuttle
missions before retiring its three-orbiter fleet in 2010. Eight of those nine
missions are space station construction flights. While there are other NASA
components of space station still yet to fly - most notably the European-built
Node 3 module and its Cupola window - none are as large as the S6 segment.
Discovery
astronauts will install the S6 truss segment on the starboard, or right-most,
side of the space station during the four spacewalks planned for their mission.
The new additions to the station represent a significant step toward
outfitting the outpost to host crews
of six people, doubled from its current capacity of three. The new solar
panels are expected to boost the station's power-generating capability by 25
percent, to a total of about 120 kilowatts of generating capacity, or enough to
power about 55 average American houses, Hardison said.
"One of the primary purposes for the power that S6 will be
providing is for going from three- to six-person crews," said Discovery's
payload manager Robby Ashley. "All of the crew systems that are required
for that sized crew, takes a lot of power draw."
SPACE.com is providing continuous coverage of STS-119
with reporter Clara Moskowitz at Cape Canaveral and senior editor Tariq Malik
in New York. Click here
for mission updates and SPACE.com's live NASA TV video feed. Live launch
coverage begins at 4:00 p.m. EDT (2000 GMT).
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