Moscow - Two Russian cosmonauts will Tuesday float out of the International Space Station (ISS) in their second spacewalk in less than a week, to install one experiment and retrieve another. ISS Commander Sergei Volkov and Flight Engineer Oleg Kononenko are expected to exit the hatch at 1710 GMT in what should be a routine maneuver, compared to last Thursday's harrowing exercise. The spacewalk is to last five-and-a-half hours.
In their spacewalk debut last week, the cosmonauts ripped through insulation to retrieve an explosive bolt from the Soyuz space capsule docked in orbit.
The retrieved bolt it 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 is to set up a new seismological experiment - dubbed Vsplesk - on the exterior of the station, which would act as an early warning system for large earthquakes.
They will also retrieve tubes of bacteria, fungi and larvae left 18 months back, as part of the Biorisk experiment, to study the effects of space on micro-organisms.
The two cosmonauts will mount 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 the crew's living space.
US Flight Engineer Greg Chamitoff, the ISS's third crew member, will remain in the Soyuz during the spacewalk, as a precaution, in case the airlock cannot be re-pressurized.
