An American astronaut and a Russian cosmonaut will step outside the International Space Station early Friday to prepare the orbital lab for a new module slated to arrive later this year.

Russian station commander Gennady Padalka and NASA flight engineer Michael Barratt are due to begin the planned 5 1/2-hour spacewalk at 2:45 a.m. EDT (0645 GMT). The spacewalkers will attach new antennas to the station's Pirs docking compartment to prepare for the arrival of the Mini-Research Module 2, a new compartment and docking port that will be launched toward the station this fall.

Padalka and Barratt will complete the installation during a second spacewalk June 10.

"These [spacewalks] are part of a bigger preparation scheme in getting ready for the launch and docking of MRM2, which is the Mini Research Module, scheduled to launch and dock to ISS in November of this year," said David Korth, Expedition 20 spacewalk flight director, during a Thursday briefing.

Barratt, who will don a Russian spacesuit with blue stripes, will be making his first ever spacewalk. Padalka, a veteran spacewalker, will be wearing a suit with red stripes to differentiate him. The spaceflyers will be testing out a new spacesuit model — the Russian Orlan MK.  The new suits include slight upgrades from previous versions, such as a different electronic control system and more adjustability in the leg, torso and arm regions for comfort, mission managers said.

The two spaceflyers arrived at the International Space Station (ISS) in March on a Russian Soyuz rocket to begin a six-month tour of duty. They are currently serving alongside Japanese astronaut Koichi Wakata, cosmonaut Roman Romanenko, Belgian astronaut Frank De Winne, and Canadian spaceflyer Robert Thirsk. The latter three arrived last week on a Russian Soyuz flight; collectively, the spaceflyers make up the station's first six-person crew (doubled from the previous crew size of three).

"They had a good weekend together, got a chance to rest and get used to more people onboard," said Courtenay McMillan, NASA's lead flight director for the station's current Expedition 20 mission. "They're all very excited to be onboard and in very good spirits."

During tomorrow's spacewalk Wakata will assist Padalka and Barratt from inside the station.  The antenna set they will install, called the Kurs antenna, will serve as a navigational beacon to guide the new module into port at the space station. Once attached, the Mini Research Module will serve as a new airlock for Russian spacewalks, and will allow spacewalkers to place scientific experiments outside the station if they need to be exposed to the space environment.

SPACE.com will provide live coverage of tomorrow's spacewalk by reporter Clara Moskowitz in New York. Click here for live spacewalk coverage, mission updates and SPACE.com's live NASA TV video feed. Friday's spacewalk coverage will begin at 2:15 a.m. EDT.