Jul 16, 2008, 0:19 GMT
Moscow - Two Russian cosmonauts floated out of the International Space Station (ISS) for nearly six hours Tuesday in their second spacewalk in less than a week, successfully installing a docking target and retrieving an earlier experiment.
ISS Commander Sergei Volkov and Flight Engineer Oleg Kononenko completed Tuesday's assignment, returned inside the ISS and locked the hatch at 2302 GMT.
In their spacewalk debut on July 10, the cosmonauts successfully retrieved an explosive bolt from the Soyuz space capsule docked in orbit. The bolt is to be examined later on Earth, in hopes of revealing why the Soyuz spacecraft have been so badly off course on their last two jolting flights back from orbit.
The main objective of Tuesday's spacewalk was to set up a new seismological experiment - dubbed Vsplesk, or Burst - on the exterior of the station, which would act as an early warning system for large earthquakes. They also retrieved tubes of bacteria, fungi and larvae left 18 months ago, as part of the Biorisk experiment, to study the effects of space on micro-organisms.
The two cosmonauts mounted a docking target for a new laboratory that Russia plans to send into orbit in 2009. The ISS addition will be used for future experiments and expand living spaces for later crews.
US flight engineer Greg Chamitoff, the ISS's third crew member, remained in the Soyuz during the spacewalk as a precaution.
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