Two spacewalkers
carefully removed a massive tank from its mooring outside the International
Space Station late Tuesday as their crewmates unpacked a treadmill named after comedian
Stephen Colbert.
Astronauts
Danny Olivas and Nicole Stott spent 6 1/2 hours working outside
the station to unhook an old ammonia coolant tank and retrieve experiments
from the orbiting laboratory's hull.
The
spacewalkers took special care because of the sheer size of the ammonia tank,
which will be replaced with a new one on Thursday. The old tank has been at the
station since 2002 and will return home aboard Discovery for an overhaul on Earth.
The tanks are
some of the most massive pieces of gear to be handled by spacewalkers and weigh
about 1,800 pounds (816 kg) when full, making them bulky - if weightless - loads
to haul in space.
The one
wrangled by Stott and Olivas was nearly empty of toxic ammonia, but still
massive at about 1,300 pounds (589 kg). It's almost 5 feet long, 7 feet wide
and 4 feet tall (1.5 m by 2.1 m by 1.2 m), so they were careful to keep it
under control until it could be grappled by the station's robotic arm.
Olivas
and Stott also retrieved a European technology experiment from the end of
the station's Columbus laboratory, as well as a materials exposure
experiment that folds up like a briefcase to be returned to scientists on Earth.
Stubborn bolts and pins made the job a bit harder, but the astronauts - and some
extra elbow grease - won out in the end.
"Good job,"
Olivas told Stott. "A good day's work."
Spacewalk
hiccups
Tuesday's
spacewalk was not without its hiccups.
About 1 1/2
hours into the excursion Olivas spotted some fraying on the index finger of his
spacesuit's right glove, but Mission Control said the defect posed no risk for
the astronaut and the spacewalk was allowed to go on.
Soon after,
a sensor in Stott's spacesuit inexplicably signaled high levels of carbon
dioxide in her spacesuit, but she told Mission Control she felt fine. Mission
Control said the sensor appeared to be giving a false reading.
Then a
severe storm over a relay station in Guam cut off communications between
Mission Control and spacewalkers, as well as the space station and shuttle, for
just over a half hour.
"You're
going to be on your own," Mission Control told the astronauts.
Astronaut
Patrick Forrester, who choreographed the spacewalk from inside Discovery, said
they'd do what they could. The spacewalkers took photographs while waiting out
Earth's silence.
COLBERT
boards space station
While the
spacewalkers worked outside, the 11 astronauts inside the station moved the new
$5
million treadmill named after comedian Stephen Colbert - of the Comedy
Central's "Colbert Report" - into a storage spot aboard the orbiting lab.
Colbert,
with the help of his fans, won the naming rights for a new space station room
during an online NASA poll earlier this year. But NASA opted to the name the
room, which launches to the station next year, Tranquility to honor of the Apollo
11 moon landing 40 years ago last month.
As a
consolation prize, NASA dubbed the station's new treadmill the Combined
Operational Load Bearing External Resistance Treadmill, or COLBERT. It arrived at the station in more than 100 pieces and packed in several bags.
Stott, who
joined the station's crew after arriving Sunday on Discovery, and her crewmates
will assemble the treadmill in mid-September. NASA officials said it should
take 20 hours to complete, so the astronauts will wait until after Discovery's departure and the arrival of an unmanned Japanese cargo ship next month to build it.
Even in
pieces, the treadmill is apparently already trying to steal the limelight. It
banged a video camera on its way into the space station.
"Looks like
COLBERT may have dislodged the camera on his way through," Mission Control
radioed the astronauts, one of whom quickly moved the camera back into place.
In addition
to the treadmill, astronauts also moved a new
astronaut bedroom and air-scrubbing equipment into the space station.
Tuesday's
spacewalk was the first for Stott. Her family watched her 6-hour, 35-minute walk in
space from Mission Control in Houston.
It was the
third career spacewalk for Olivas, who is leading the three spacewalks planned
for Discovery's 13-day mission. He ended the day with 20 hours and 48 minutes. The spacewalk was the 131st dedicated to space station construction or maintenance.
More unpacking
is on tap for station and shuttle astronauts on Wednesday. They plan to unload
a pair of sophisticated new experiment racks to study fluid physics and new
materials in weightlessness. The next spacewalk is set for Thursday.
SPACE.com
is providing complete coverage of Discovery's STS-128 mission to the
International Space Station with Managing Editor Tariq Malik and Staff Writer
Clara Moskowitz in New York. Click
here for shuttle mission updates and a link to NASA TV.
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