International Space Station Commander Sergei Volkov and Flight Engineer Oleg Kononenko began a spacewalk at 2:48 p.m. EDT Thursday to inspect and retrieve an explosive bolt from their Soyuz TMA-12. The bolt will be returned to Earth for examination.
The spacewalk comes in the wake of two consecutive ballistic entries by the previous Soyuz spacecraft, entries that resulted in high-G rides for the crews and landings hundreds of miles short of the planned recovery area. Russian engineers say they have evidence that failed explosive bolts that help separate two modules likely are responsible.
The spacewalk is expected to last about six hours. It focuses on the area between the Soyuz return and propulsion modules.
Volkov and Kononenko leave the Pirs docking compartment and move to the Strela hand-powered crane mounted nearby. Volkov, wearing the red-striped Orlan spacesuit and designated EV1, and Kononenko mount a foot restraint on the end of Strela.
Kononenko, EV2 in the blue-striped suit, gets into the foot restraint and Volkov maneuvers him to the Soyuz, docked to the Earth-facing port on Pirs.
After installing covers to protect nearby thrusters, Kononenko cuts and secures insulation and inspects and photographs the area. Then Volkov moves along the Strela to join Kononenko, who installs a handrail on the Soyuz and a cover to protect fluid lines.
Volkov cuts a wire tie between adjacent pyrotechnic bolts in the suspect position and demates an electrical connector. Next he unscrews and retrieves the pyro bolt and stows it in a protective cylindrical case. He reinstalls the insulation cover and removes the thruster covers, taking photos after each step.
Kononenko and Volkov move back to the Strela controls and both maneuver the crane back to its stowage position on Pirs. They stow a bag with the blast-proof container holding the pyro bolt in the airlock.
If time permits, they install a docking target on the space-facing side of the Zvezda service module. It will help with the docking of a Russian mini-research module atop Zvezda. The module will be delivered on a future mission.
The cosmonauts return to Pirs, enter the airlock and close the hatch.
Flight Engineer Greg Chamitoff remains in the Soyuz during the spacewalk, part of contingency preparations for the unlikely event the Pirs airlock cannot be repressurized.
Volkov and Kononenko will conduct another spacewalk July 15 to outfit the Russian segment's exterior and install a scientific experiment and retrieve another.
