Astronauts aboard the International Space
Station (ISS) have a long Super Bowl Sunday ahead as they prepare to venture
outside the orbital laboratory for their second spacewalk in less than a week.
Expedition
14 commander Michael
Lopez-Alegria and flight engineer Sunita
Williams are expected to once more don their NASA spacesuits and begin the second
of three planned spacewalks in nine days Sunday at 9:00 a.m. EST (1400 GMT) [image].
Their goal: the completion of an ISS cooling system overhaul that began during
a nearly eight-hour excursion on Wednesday [video].
"That's
Super Bowl Sunday," said Glenda Laws, NASA's lead Expedition 14 extravehicular
activity (EVA) officer, of tomorrow's spacewalk. "We'll get that EVA out of the
way though in plenty of time for everyone to watch the football game
afterwards."
Laws said
that the Expedition
14 spacewalkers will again take great care while handling ISS cooling lines
to avoid leaks of the station's toxic ammonia coolant.
Lopez-Alegria
and Williams are performing an unprecedented three
EVAs in two weeks, and expect to spend around six hours working outside the
ISS on Sunday. Lopez-Alegria is also expected to make a fourth, unrelated
spacewalk on Feb. 22 with Russian cosmonaut and flight engineer Mikhail
Tyurin.
The
spacewalk marathon marks the most densely-packed series of EVAs without a visiting
NASA space shuttle crew.
Shuttle astronauts routinely make several spacewalks within days of one another
while docked at the ISS on relatively short missions. But fatigue and wear are
larger concerns for the long-duration astronauts assigned to station Expedition
crews, NASA officials said.
During the
Expedition 14 crew's spacewalk quartet, the astronauts are routinely discussing
their energy levels and personal health with flight surgeons on Earth, mission managers said.
"The health
of the crew, the stamina of the crew is something that we watch very closely," Derek
Hassmann, NASA's lead ISS Expedition 14 EVA flight director, said after the
Jan. 31 spacewalk.
Cooling
system work awaits
Clad in
bulky NASA
spacesuits, Lopez-Alegria and Williams duties on Sunday are mostly a mirror
image of their previous Jan. 31 spacewalk. As in that excursion, Lopez-Alegria
will sport a spacesuit marked with red stripes while Williams' spacesuit will
be white with no stripes [image].
"We're
hoping that with everything that we learned about body positions and so on...that
we'll be able to move through the operations on the [cooling] loop reconfig
will go a bit smoother next time," Laws said.
During
their Wednesday
spacewalk, Lopez-Alegria and Williams switched the space station's Loop A
cooling system from a temporary set up - which shed heat from a radiator on
the outpost's mast-like
Port 6 truss - to a permanent configuration that runs through heat
exchangers in the station's U.S.
Destiny module. On Sunday, the spacewalkers will tackle the second half of
that cooling system, Loop B, while taking care to avoid any leaks of toxic
ammonia coolant in a worksite renown for its tight squeezes and "Rat's Nest" of
electrical and plumbing lines [image].
Once the
cooling system work is complete, the Expedition 14 spacewalkers will watch over
the remote-controlled retraction an aft-facing radiator on the Port 6 truss
that is no longer required [image].
The
astronauts also plan to retrieve the second of two fluid lines on an unneeded
reservoir filled with ammonia coolant, photograph a solar array extending to
starboard from the Port 6 truss, and wire up a power transfer system that will
allow future NASA space shuttles to
spend more time docked at the ISS by drawing on the outpost's power supply.
If any
spare time remains, the spacewalkers could perform extra tasks -- known as get
aheads -- which include taking snapshots of the station's shuttle docking port
to determine if any corrosion or debris is responsible for spotty communication
links between the ISS and visiting orbiters during recent NASA shuttle missions. But
Laws stressed that completing the spacewalk's primary chores remain the
Expedition 14 crew's top priority.
"We'll take
our time, we'll do what it takes," Laws said after the Jan. 31 spacewalk. "We'll
get to the get aheads when we get to the get aheads."
Sunday's
planned Expedition 14 spacewalk is scheduled to begin at 9:00 a.m. EST (1400
GMT). NASA will begin broadcasting the space station crew's spacewalk
activities live on NASA TV at 8:00 a.m. EST (1300 GMT).
advertisement
