July 11, 2008

Russian Cosmonauts Complete Unscheduled Spacewalk, Return to Iss

KOROLYOV (Moscow region). July 11 (Interfax-AVN) - Members of Expedition 17 at the International Space Station (ISS) Sergei Volkov and Oleg Kononenko have returned to the Pirs docking compartment after spending six hours in outer space.

"They managed to complete one of their tasks and have now entered the airlock of the Russian ISS segment," a source at Russian Mission Control Center told Interfax-AVN.

The purpose of the spacewalk was to inspect and detach one of the five clamp units connecting the return and propulsion modules of the Soyuz TMA-12 spacecraft. While detaching the unit, the cosmonauts retrieved a pyro bolt to take it to the station. It will be later taken to Earth for study. Experts at the Russian Space Agency believe a pyro bolt was what caused the recent perilous (ballistic) descents of two Russian Soyuz spacecraft: the Soyuz TMA-10 in October 2007 and Soyuz TMA-11 in April 2008.

A ballistic descent is different from a normal descent in that it proceeds in a free-falling trajectory of the spacecraft flying towards Earth, with the crew experiencing high Gs and landing hundreds of kilometers off the designated spot. The Soyuz TMA-11 crew experienced 8-9G, instead of the 3-4G of a normal-trajectory return from orbit, and landed more than 400 kilometers off the designated spot.

Meanwhile, Alexander Volkov, the father of ISS crew commander Sergei Volkov, is concerned by the pyro bolt problem.

"The Soyuz spacecraft have remained the same on the outside, but they have changed on the inside: they have new computers, a control panel. The spacecraft control principles are the same, but they are now at a higher level," he said.

"Old Soyuz spacecraft did not have problems with pyro bolts," he said.

"I spoke to engineers, cosmonauts who now work for the Energia rocket and space corporation, and they say that nothing has been changed in the structure of the spacecraft. This is even more alarming," Volkov said.

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