Twoastronauts will step outside the International Space Station tonight to add newexperiments to the orbiting laboratory?s hull, including one to aid an ongoinginvestigation into recent Russian Soyuz spacecraft glitches.
Spacestation commander Michael Fincke of NASA and Russian cosmonaut Yury Lonchakov aredue to float outside the station in Russian-built Orlan spacesuits at about7:10 p.m. EDT (0010 GMT) and spend just over six hours working outside.
?I will goout the door first,? Fincke said in a video message last week. ?It?s going tobe very exciting.?
Their firsttask is the installation of a Langmuir probe, an instrument that will monitorthe plasma environment near a Soyuz docking port on the station?s Russian-builtPirs docking compartment.
The tool isdesigned to give engineers in Russia more information on the plasma environmentnear the docking port, which is suspected to be responsible for explosive boltmalfunctions on two of the lastthree Soyuz spacecraft to return astronauts from the space station. Russianengineers believe electrical arcs near oneof the bolt locations caused it to fail during module separation on thoselandings, which sent the Soyuz vehicles to land off-target and subjected their crewsto higher gravitational loads.
?Thisactual task was added as a direct consequence to the commission to understand exactlywhat happened with the Soyuz,? said Kirk Shireman, NASA?s deputy space stationprogram manager.
In additionto the plasma probe, Lonchakov and Fincke will attach two experiments, EXPOSE-Rand Impuls to the exterior to of the station?s Russian Zvezda module.
The EXPOSE-Rexperiment is a joint project between the European Space Agency and Russia?sFederal Space Agency to understand how organic materials behave in the vacuumof space. The Impuls experiment is a tool aimed at studying the plasmaenvironment of Earth?s ionosphere.
?This[spacewalk] is going to expand our science capability,? said space stationflight director David Korth.
Lonchakovand Fincke also plan to retrieve a canister-like Biorisk container filledbacteria and fungi as part of a study on how changes in solar activityaffect their growth.
Flightcontrollers also want the astronauts to close a loose insulation flap andreposition a misaligned space exposure experiment. If extra time is available,the astronauts may also conduct a photo survey of the space station?s Russian segmentwith a focus on a navigation antenna that failed to work properly during arecent cargo ship?s arrival.
Today?s workoutside the space station will be led by Lonchakov, who will make his first spacewalk.It will be the fifth spacewalk for Fincke, who is commanding the space station?sExpedition 18 mission. Their third crewmate, NASA astronaut Sandra Magnus, willremain inside the space station during the spacewalk.
Fincke said he was looking forward to trying out the new helmet lights for hisRussian-built Orlan spacesuit, which he emblazoned with an American flag shoulderpatch.
?I?m proud tobe an American working on station and it?s really cool working with the Russianpartners,? Fincke said last week. ?I?m glad they trust me with one of theirsuits to help out with the plan.?
NASAwill broadcast tonight?s spacewalk live on NASA TV beginning at 6:30 p.m. EDT (2330GMT). Click here for a link to SPACE.com?sNASA TV feed and International Space Station mission updates.
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