This
story was updated at 9:30 a.m. EDT.
Two
spacewalkers replaced an old door on the International Space Station early
Wednesday during a rare - and brief - internal service call that primed the
outpost for the arrival of a new Russian-built room later this year.
Russian cosmonaut
Gennady Padalka and American astronaut
Michael Barratt spent just 12 minutes working in close quarters to remove
the roof-mounted hatch cover in the forward transfer compartment of the
station's Zvezda service module. They replaced the door with a docking cone
that will allow Russia's new Mini-Research
Module 2 to latch onto the station in November.
"I think
this is it," said Padalka, who commands the station's six-man Expedition 20
crew. "Michael, you did such a great job replacing that cover."
It was a
tight fit for the two spacewalkers. Zvezda's small spherical transfer
compartment is only five feet (1.5 meters) across at its widest point, giving
little room for Padalka and Barratt to move in their bulky Russian spacesuits.
"Michael,
do you have enough space there?" asked Padalka after they two men squirmed into
position.
"Yeah, I
have more than enough," Barratt replied.
An
inside job
Today's
spacewalk began at 2:55 a.m. EDT (0655 GMT) and finished 12 minutes later,
though Padalka and Barratt had a more than six-hour supply of air in case the
door swap went awry. At no point did the two spacewalkers exit the space
station or detach the spacesuit umbilical cables linking them to the outpost.
Not since
2001 have spacewalkers worked inside the
space station in a vacuum, NASA officials said. That earlier spacewalk was
performed on June 8, 2001 - nearly eight years to the day of Wednesday's work -
by the station's then-Expedition 2 crew to prime Zvezda to receive its
Earth-facing Pirs docking compartment. It lasted 19 minutes.
NASA and Russia's
Federal Space Agency consider any activity in which astronauts and cosmonauts
work in a vacuum as a spacewalk. Russian spacewalks are timed by the duration
between a hatch opening and closing, while NASA spacewalks are measured by the
period between the switch to a spacesuit's internal battery power and airlock
repressurization. Russian cosmonauts also performed three internal spacewalks
in 1997 to inspect and repair a damaged module on Russia's Space Station Mir.
The
internal spacewalk by Padalka and Barratt was the second excursion dedicated to
preparing the space station for its new Russian room. The two spacewalkers
ventured outside the station on June 5 to install docking antennas that will
help the Mini-Research Module 2 attach to its final berth when it arrives this
fall.
Russia's
new station room
With the
new docking cone installed, the space station's Zvezda module is now a step
closer to welcoming Mini-Research Module 2, a new room slated to launch toward
the outpost atop an unmanned rocket.
The module
will add a new docking port to the space station, which currently has four
available berths, three on the Russian segment and one at the front of the
outpost on NASA's Harmony connecting node.
The space
station needs more docking ports to support its larger, six-person
crew, which took up residence earlier this month. In addition to Padalka
and Barratt, another Russian cosmonaut and astronauts from Japan, Belgium and
Canada currently live aboard the space station.
Two Russian
Soyuz vehicles are currently parked at the station as lifeboats and a taxi home
for the six spaceflyers aboard. An unmanned Progress cargo ship is docked at
the remaining Russian port.
The
Mini-Research Module 2 will also serve as an airlock for Russian spacewalks and
will have exterior attach points for future experiments, NASA officials said.
Russia's
Federal Space Agency built two Mini-Research Modules for the station at the
same time and always planned to launch the first one completed to the outpost
atop an unmanned booster, NASA officials told SPACE.com. Mini-Research
Module 2 was completed slightly ahead of its counterpart and jumped to the head
of the line, they added.
NASA and
Russia plan to launch the Mini-Research Module 1 to the station in May 2010
aboard the U.S. space shuttle Atlantis.
Shuttle
mission ahead
Wednesday's
spacewalk was the 125th excursion dedicated to station
construction and maintenance. It was the eighth spacewalk for Padalka, who
finished with 27 hours and 15 minutes of spacewalking time. It was the second
career spacewalk for Barratt, who ended with just over five hours of orbital
work.
The six men
aboard the space station have an extended rest period ahead as they prepare for
the arrival next week of NASA's shuttle Endeavour and seven more astronauts.
Endeavour
is slated to launch Saturday morning from Florida to deliver a porch-like
experiment platform for the station's Japanese Kibo lab, as well as new solar
array batteries and spare parts. Five spacewalks are planned for the 16-day
shuttle mission.
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