Russians begin spacewalk outside station

Two cosmonauts this morning floated outside the International Space Station to begin a planned six-hour spacewalk, the first since one NASA astronauts performed during last month's final shuttle mission.

Russians Sergei Volkov and Alexander Samokutyaev, flight engineers on the station's six-person Expedition 28 crew, opened the Pirs airlock hatch about 20 minutes later than planned at 10:50 a.m. EDT.

The Russian duo plans to move a cargo boom from one airlock to another, install a prototype laser communications system and deploy an amateur radio micro-satellite.

The 57-pound satellite (left) carries a student experiment, greetings in native languages from students around the world and also messages celebrating the 50th anniversary earlier this year of the first human flight in space by Yuri Gagarin.

The move of the cargo boom from the Pirs to Poisk docking compartments is the big job, expected to take about three hours.

The spacewalk will be the third for Volkov, 38, who performed two during a previous long-duration stay on the station in 2008. It's the first for the 41-year-old Samokutyaev.

Both will wear Orlan-MK spacesuits marked with blue stripes and equipped with U.S. helmet cameras.

Click the NASA TV box at right to launch a viewer and watch the spacewalk live.

During the excursion, the four other Expedition 28 crew members will be split up as a standard safety precaution during spacewalks out of the Pirs airlock.

Russian Andrey Borisenko, the current station commander, and American Ron Garan will be inside the Soyuz 26 spacecraft docked opposite the depressurized airlock to make sure they could safely escape in an emergency.

American Mike Fossum and Satoshi Furukawa of will work as usual in the station's U.S. segment, with access to a Soyuz 27 lifeboat docked to the Russian Zarya module.

The spacewalk is the 29th by cosmonauts supporting space station assembly and maintenance, and the 161st overall.