Two Russian cosmonauts plan to install a docking target and
swap out science experiments during a Tuesday spacewalk outside the
International Space Station.
The five-and-a-half hour spacewalk is set for 1:08 p.m. EDT (1708
GMT), as the second of two spacewalks conducted by space station commander
Sergei Volkov and flight engineer Oleg Kononenko.
Both cosmonauts were first-time spacewalkers when they
successfully removed
an explosive bolt from the Russian Soyuz spacecraft outside the space
station on July 10. The six-hour,
18 minute spacewalk was added per Russian request as part of the continuing
investigation into a mysterious malfunction that has caused the two most recent
Soyuz spacecraft to go off-course
during re-entry.
The second spacewalk will focus on the original duties for
the initial spacewalk that were pushed back to allow for the Soyuz inspection,
NASA officials said at a press briefing July 8.
Those duties include placing the docking target for an
upcoming mission, removing a biological experiment and putting a high-energy
physics experiment in place. Russian mission controllers had hoped that the
cosmonauts could install the docking target on the space station's Zvezda
module during the July 10 spacewalk, but eventually opted to give Volkov and
Kononenko a break.
The second spacewalk will start off with Volkov and
Kononenko placing the docking
target for a new airlock called the Mini-Research Module 2 (MRM2). That
will replace the Pirs docking compartment as the main airlock for the Russian
part of the space station, after its delivery in 2009 by an unmanned Russian
Progress spacecraft.
Both spacewalks have required the cosmonauts to exit from
the Pirs docking compartment, which also represents the only passage between
the space station and the Soyuz spacecraft that serves as an emergency lifeboat.
U.S. astronaut Greg
Chamitoff will once again spend the entire spacewalk sitting inside of the
Soyuz, so that he does not get cut off in the unlikely event of a crisis.
Kononenko will install the docking target by riding the long
arm of the Strela hand-powered crane to the Zvezda module. Volkov will operate
the hand-powered crane and move his fellow astronaut to the target location.
Next, the cosmonauts will use a spacewalker's ladder and
move to a different part of Zvezda to inspect some bolt holes. The holes will
serve as the location for a future antenna adapter that will serve the Kurs
automated docking system.
A quick trip back to Pirs should allow the cosmonauts to get
the Vsplesk, also known as Burst, experiment and install it on the Russian
module. Burst will gauge the seismic effects of high energy particle streams in
orbit around the earth.
Lastly, Volkov and Kononenko aim to retrieve the Biorisk
experiment installed by Expedition 15 spacewalkers on the Russian module. That
long-running experiment looks at the effects of solar radiation and zero G on
microbes and other small organisms.
Volkov will wear the Orlan spacesuit with red stripes as
lead spacewalker (EV1), while Kononenko will wear a blue-striped suit (EV2).
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