Two Russian
spacewalkers will step outside the International Space Station (ISS) for the
second time Wednesday to finish attaching new micrometeorite shields to their high-flying
laboratory's hull.
ISS
Expedition 15 commander Fyodor Yurchikhin and flight engineer Oleg Kotov are
due to begin the second spacewalk of their six-month space mission at 10:30
a.m. EDT (1430 GMT).
"It's very
important that we continue with our Russian EVAs," Yurchikhin told reporters
before a May 30
spacewalk, or extravehicular activity (EVA), also aimed at installing new
ISS shielding.
Yurchikhin
and Kotov are both making their second career spacewalks with today's
excursion, which also comes two days before the planned launch of NASA's space shuttle Atlantis carrying
seven astronauts and new solar arrays bound for the ISS.
Expedition
15 flight engineer Sunita Williams will watch over the progress of her two
crewmates from inside the ISS and help choreograph their activities.
Guarding
against space rocks
Clad in
their Russian-built Orlan spacesuits, Yurchikhin
and Kotov are expected to spend just over five hours attaching 12 one-inch
(2.5-centimeter) thick metal panels and other equipment to the exterior of the
space station's Russian segments. The spacewalkers attached five other panels,
known as Service Module Debris Panels, on the outpost's Zvezda service module
during their excursion last week.
Each panel
weighs between about 15 and 20 pounds (about seven to nine kilograms) and
covers a two-foot by three-foot (0.6 by 0.9 meters) patch of space station
hull, NASA officials said. The shields will help guard the space station
against damage from tiny space rocks -- or micrometeorites -- and orbital
debris from jettisoned rocket stages, satellites and other spacecraft. The
potential collision with micrometeorites and debris has been one of the top
risks to the space station, NASA has said.
"We've been
working on these for years, actually since prior to the first launch of the
space station," Kirk Shireman, NASA's deputy ISS program manager, said of the
increased shielding. "We actually launched the space station in 1998. And
through 2016, if you look at that life, there's a lot of debris that we'll fly
through in that time frame and so that's why it's our highest risk."
Outfitting
ISS
In addition
to installing the new station shielding, Yurchikhin and Kotov are expected to
thread a 43-foot (13.1-meter) Ethernet cable along the exterior of the ISS and
attach a Russian science experiment to the orbital laboratory's hull.
The Ethernet
cable, which will run along handrails mounted to the station's Russian-built
Zarya control module, is part of a computer system upgrade for the ISS. A
second cable will be installed in a later spacewalk.
Biorisk,
a Russian-built experiment to study the effect of weightlessness on
microorganisms, will also be mounted to the space station's Pirs docking
compartment -- the starting point for today's EVA -- during the spacewalk. Its
three cylindrical sample containers will be retrieved by future spacewalkers.
"It will be
the first EVAs for both of us and we're really looking forward to performing
this job," Kotov told reporters before the two spacewalks. "We're very
well-trained and that's why we're very sure of our success."
NASA
will broadcast today's spacewalk outside the International Space Station live
on NASA TV beginning at 10:00 a.m. EDT (1400 GMT). Click here for SPACE.com's live spacewalk
updates and NASA TV feed.
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