Armored ISS: Cosmonauts Outfit Space Station with New Shields
Expedition 15 commander Fyodor Yurchikhin (right) and flight engineer Oleg Kotov pause to take photographs during a June 6, 2007 spacewalk to install new debris shielding and other equipment to the exterior of the International Space Station.
Credit: NASA TV.

The International Space Station (ISS) has new armor to guard against wayward meteorites and orbital debris after a successful Wednesday spacewalk by two Russian cosmonauts.

Expedition 15 commander Fyodor Yurchikhin and flight engineer Oleg Kotov attached a dozen metal plates to a Russian segment of the ISS and found signs of past damage in some areas.

"We found a dent or a hole from a meteorite," Yurchikhin told mission controllers in Russia from his perch atop the station's Zarya control module. "It looks like a bullet hole. I want to say the size is about five to six millimeters."

Yurchikhin and Kotov installed the new debris shields and other equipment on the space station's outer hull during a five-hour, 37-minute spacewalk that began at 10:23 a.m. EDT (1423 GMT) as the orbital lab flew 220 miles (354 kilometers) above the horn of Africa.

Wednesday's spacewalk marked the second in eight days for the Expedition 15 crew. Yurchikhin and Kotov also installed orbital debris shields and performed other tasks during a May 30 spacewalk. NASA astronaut Sunita Williams, an Expedition 15 flight engineer, monitored her spacewalking crewmates from inside the ISS during both spacewalks.

The Expedition 15 crew is now gearing up for the arrival of NASA's STS-117 astronauts aboard the shuttle Atlantis, which is slated to launch towards the ISS on June 8.

More shields, new equipment

Yurchikhin and Kotov attached 12 aluminum panels to a sensitive area of the space station's Russian-built Zvezda service module -- which houses the ISS crew quarters -- during their Wednesday spacewalk.

"Everything is excellent," Yurchikhin said during the installation. "I guess we're lucky."

The new panels, along with five others installed by the Expedition 15 crew during the May 30 spacewalk, give Zvezda additional protection against impacts from micrometeorites and orbital debris. NASA officials have said that such micrometeorite and orbital debris (MMOD) strikes represent a major risk to the ISS and NASA shuttles in Earth orbit.

"The number one risk for the shuttle is MMOD when it's on orbit," Kirk Shireman, NASA's deputy ISS program manager, said before today's spacewalk. "It's also that way for ISS, although the station was designed to live in a debris environment."

Each of the 17 aluminum plates installed by Yurchikhin and Kotov during their two spacewalks are about an inch (2.5 centimeters) thick and cover a two-foot by three-foot (0.6- by 0.9-meter) patch of the ISS, NASA officials have said. They join six other panels that were installed by ISS astronauts during a 2002 spacewalk.

In addition to the new shields, Yurchikhin and Kotov mounted a Russian experiment dubbed Biorisk to the station's exterior to study the effects of weightlessness on microorganisms.

The cosmonauts also ran a 43-foot (13.1-meter) Ethernet cable across the top of the station's Russian-built Zarya control module as part of a computer network upgrade that will, once complete, allow astronauts to control the outpost's Russian segments from the U.S. modules, NASA officials said.

By the numbers, Wednesday's spacewalk marked the 83rd excursion dedicated to ISS construction or maintenance and the 55th to originate from the orbital laboratory itself. It was also the 22nd excursion to begin at the station's Pirs docking compartment.

More spacewalks ahead

Both Yurchikhin and Kotov now have two spacewalks, totaling of 11 hours and two minutes of orbital work, under their belts. Yurchikhin will add to that experience during a third spacewalk planned for the Expedition 15 mission.

But that spacewalk, a U.S. excursion in NASA spacesuits, must wait until after the upcoming STS-117 shuttle mission to the ISS, which will deliver American astronaut Clayton Anderson to the orbital laboratory. Atlantis astronauts will stage at least three spacewalks during their 11-day mission to install new solar arrays and trusses to the space station's starboard side.

Anderson will relieve Williams as an Expedition 15 crewmember and will participate in the U.S. spacewalk with Yurchikhin.

"It's so dynamic," Yurchikhin said of during today's spacewalk as he and Kotov took pictures while resting between tasks. "It's just like an action movie."