Untitled Document
The International Space Station (ISS) is a little better
protected against impact by stray particles today after two Russian cosmonauts
installed debris shielding to the station during a 5 hour, 25 minute spacewalk.
Expedition
15 commander Fyodor Yurchikhin and flight
engineer Oleg Kotov installed five Service Module
Debris Protection (SMDP) panels to the Zvezda service
module of the orbital laboratory and also rerouted a Global Positioning System antenna cable. The spacewalk was a first for both
cosmonauts.
“Look at that sunset,” said one of the spacewalkers
while outside the ISS. “It’s amazing.”
“Oh yes, I’ve already had a look,” the other
one replied.
Flight engineer Sunita Williams
remained inside the space station and provided support for the spacewalkers.
The number one risk
The Russian-built Zvezda Module functions
as a living quarters for the ISS and is also responsible for some life support
system functions for the station. It was launched in 2000 without adequate
shielding against impacts by micrometeorites and orbital debris, with the
intention of adding additional protection during future spacewalks.
The SMDP panels are designed to protect the ISS from small- and
medium-sized micro
meteoroid orbital debris (MMOD) that could strike the space station and
cause a potentially catastrophic hull rupture.
“This is one of area we share with our shuttle
brothers,” said ISS Deputy Manager Kirk Shireman before the spacewalk. “The number one risk for the shuttle is MMOD impact
when it’s on orbit. It’s also that way for the ISS.”
Each aluminum panel measures about two feet by three feet, is
about one inch thick and weighs 15 to 20 pounds.
A late start
The spacewalk kicked off at 3:05 p.m. EDT (1905 GMT), after a
45 minute delay caused by a communication problem between ground controllers and
the space station encountered during preparations. The spacewalk was soon back on schedule, however, because the cosmonauts were able
to work through periods of darkness using the light of an almost full moon.
After exiting the Pirs airlock, Yurchikhin and Kotov set out to
retrieve three bundles of SMDP panels that were delivered to the space station
by the space shuttle Discovery last December, and which were stowed outside the
ISS on a mount known as the “Christmas
Tree.”
Using a robotic boom called Strela 2, the spacewalkers
transferred and secured the three bundles, containing a total of 17 panels, to
a grapple fixture on Zvezda. Unwrapping one of the
bundles, Yurchikhin and Kotov installed five shield panels to the sloping conical section of Zvezda.
The pair will install the remaining 12 panels
during a second spacewalk scheduled for June 6. Six panels were installed
during a previous spacewalk in 2001.
Between the retrieval and installation of the SMDP panels, Yurchikhin and Kotov also took
some time to route a Global Positioning System (GPS) Ethernet
cable to an antenna that will help guide the European Automated Transfer
Vehicle (ATV) when it docks with Zvezda.
The
unpiloted ATV is a cargo carrier with almost twice the storage capacity of the
current Progress cargo craft; it is scheduled to make its maiden flight later
this year.
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