The two astronauts living
aboard the International Space Station (ISS) are preparing for the first
spacewalk of their mission with a combination of experience and enthusiasm, NASA
flight controllers said today.
ISS Expedition 10 commander
Leroy Chiao, a spacewalking veteran, and flight engineer Salizhan Sharipov
plan to exit the orbiting facility on Jan. 26 for a 5.5-hour job of installing
new hardware on the station's exterior.
"The Expedition 10 crew is
in great shape and doing extremely well," said Derek Hassman, Expedition 10's
extravehicular activity (EVA) flight director, during a press briefing at NASA's
Johnson Space Center today. "The crew is extremely focused and we're very
excited about going out the door next week."
That focus will come in
handy for Chiao and Sharipov, who will have to pull themselves equipment across
100 feet (30
meters) of space station exterior - starting from the Russian Pirs docking
compartment - to reach their first EVA worksite outside the
Zvezda service module. The Expedition 10 crew will have to make to make the
trek hand-over-hand, toting themselves and their equipment without the aid of an
extendable 50-foot (15
meter) boom - called Strela - that has served as a shortcut for past ISS
spacewalks.
"The Strela EVA crane is
unable to reach this worksite," said Scott Bleisatch, Expedition 190's lead EVA
officer, during the briefing.
Chiao and Sharipov will don
Russian-built Orlan spacesuits during the spacewalk.
Work ahead
During their spacewalk, Chiao and
Sharipov are expected to attach two commercial payloads, including the
German-built Rockviss robotic experiment, life science study hardware and
other scientific equipment, to the space station's exterior. The Expedition 10
crew will also inspect three exhaust vents to determine if any of them have
become clogged.
One of those vents is used
by the space station's Elektron
oxygen generator to expel excess hydrogen, while another is used by a
Russian-built system to scrub carbon dioxide from the cabin air, Hassman said.
The third vent is used to screen the atmosphere for trace contaminants, he
added.
Since both Expedition 10
crewmembers will be working outside the ISS during the EVA, flight
controllers will monitor the empty space station interior from the ground. ISS
crew complements have been limited to two members - as opposed to the typical
three person details - since the grounding of NASA's space shuttle fleet
following the loss of Columbia and its seven-astronaut crew.
"One of the challenges has
been that we don't have the third crewmember inside to respond to unexpected
circumstances," Hassman said, adding that Chiao and Sharipov will close a number
of hatches to safeguard the ISS while flight controllers monitor station status
from the ground.
Flight controllers will
also watch the performance of NASA-built ISS stabilizers called control moment
gyroscopes in case the added strain from the spacewalk puts too great a load on
them. If that occurs, the space station would rely on Russian thrusters for
orientation, but would have to drift
freely if Chiao and Sharipov are working near any of the thruster nozzles.
NASA officials said the ISS
could float in a free-drift mode for no more than 45 minutes before a correction
would be required, but the only Expedition 10 work task that would conflict with
the thruster system should only take about 30 minutes.
Looking
forward
Chiao is no stranger to
working with only a spacesuit for protection from the harsh environment of
space. He has made four EVAs during two past shuttle flights to help build
the ISS. The Jan. 26 spacewalk will be his first EVA staged from the space
station. It will also be the first spacewalk ever for Sharipov, who served as a
mission specialist aboard the shuttle Endeavor during its 1998 flight
to the Russian space station Mir before joining Expedition 10.
"It's very interesting to
me to be able to make such an experience in space," he said to a reporter this
week during an interview broadcast on NASA TV.
NASA officials said that,
under direction from Russian flight controllers, Chiao and Sharipov will both
wear Orlan spacesuits marked by a red stripe during the spacewalk,
departing a bit from the typical red stripe-blue stripe spacesuits to delineate
who's who out in space. Chiao's spacesuit will bear the U.S. flag in order to
tell the two men apart, they added.
The Jan. 26 EVA is set to
be the 57th spacewalk in support of ISS maintenance and the 42nd
staged from the space station itself as opposed to the space shuttle. It is
expected to be the 14th spacewalk for work on the Zvezda module.
Complete
Coverage: ISS Expedition 10
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