The International Space Station's two Russian astronauts are conducting
a spacewalk Tuesday to install a docking target for a Russian research
module scheduled to arrive next year.
In a statement on its Web site, the U.S. space agency, NASA, said ISS commander Sergei Volkov and flight engineer Oleg Kononenko are expected to be outside the space station for 5.5 hours.
During their walk, the astronauts will also install a new science experiment on the station and remove an old one that measured the effects of the space environment on microorganisms.
This is the Russian astronauts' second spacewalk in a week. Last Thursday, they removed an explosive bolt from their Soyuz spacecraft docked at the spacestation.
The bolt had the explosive power of a large firecracker. It was one of several used to separate the Soyuz's crew compartment from its equipment module.
Russian space engineers believe faulty explosive bolts may have caused two previous Soyuz capsules to re-enter the Earth at excessive speeds and an incorrect angle.
Some information for this report was provided byAP.