Spacewalking Astronauts Outfit ISS For New Cargo Ship

Expedition 10 flight engineer Salizhan Sharipov ties the satellite NanoSputnik to the Pirs docking compartment exterior during his second spacewalk on March 28, 2005. He later deployed the small satellite by tossing it into space. CREDIT: NASA TV.

Two astronauts are safely back inside the International Space Station (ISS) after apparently breezing through an early morning spacewalk designed to prepare the orbital facility for a new cargo ship.

ISS Expedition 10 commander Leroy Chiao and flight engineer Salizhan Sharipov left the space station empty as they worked outside clad in Russian-built Orlan spacesuits.

The two men were consistently ahead of schedule as they installed antennas and photographed the space station, ultimately completing their tasks 4.5 hours after leaving the Pirs docking compartment at 1:25:20 a.m. EST (0625:20 GMT).

"Now that we have time to actually look around, it's too bad it's all dark outside," said Chiao as he prepared to reenter the ISS as it flew over an Earth draped in night.

Chiao and Sharipov worked primarily on the space station's Russian Zvezda service module, installing a trio of navigation antennas around its conical smaller section. The space-to-space antennas - known as WAL antennas - will be used to aid the docking operations of Europe's Automated Transfer Vehicle (ATV) during future ISS-bound cargo mission.

Another piece of hardware - a global positioning system (GPS) unit attached to Zvezda during the spacewalk - will also aid the ATV, which NASA officials said is expected to arrive at the ISS sometime next year.

NASA officials said the first ATV, called Jules Verne, will be able to deliver 8.5 tons of cargo to the ISS, including some 10,000 pounds (4,535 kilograms) of propellant.

NanoSputnik

In addition to installing the new antennas, the Expedition 10 crew also deployed a small satellite in what may be the ultimate Hail Mary pass.

After the Expedition 10 crew successfully connected the first three antennas, Sharipov returned to the Pirs docking compartment, to which he had lashed the small satellite NanoSputnik. Weighing just 11 pounds (five kilograms) and about one foot in length, the satellite carries a transmitter and is designed to test small spacecraft control and orientation systems over about 100 days in space.

"Off it goes," Sharipov said as he threw the long nanosatellite into space at a velocity of about one meter (3.2 feet) per second. "It's rotating a bit, but it should be okay."

Sharipov tossed NanoSputnik into a retrograde orbit - opposite the direction of the space station's motion - at about 3:31 a.m. EST (0831 GMT) while Chiao photographed the in-space launch.

"Congratulations and huge thank you to you because our scientists are saying they are getting a signal from the satellite," Russian flight controllers later told Sharipov.

Just a small drift

Before Chiao and Sharipov could move back to the Zvezda module and install the GPS unit, Russian flight controllers had to take the space station's attitude control thrusters - which help the ISS maintain its position - offline to avoid harming or contaminating the spacewalking duo with toxic propellant.

Instead, the space station's attitude was kept in check by U.S.-built gyroscopes. U.S. flight controllers had only anticipated the station's two working gyroscopes last about 30 minutes, after which time the loads on the ISS would be too great and the station would be left to drift while the Expedition 10 crew completed their work near the Russian thrusters.

But NASA commentators said the gyroscopes performed much longer than anticipated, and were only overwhelmed at 5:15 a.m. EST (1015 GMT). The ISS drifted freely for less than an hour, a dramatic difference from the three hours expected by U.S. flight controllers.

By 6:31 a.m. EST (1131 GMT), Chiao and Sharipov had repressurized the Pirs docking compartment and doffed their space suits. The successful extravehicular activity marked the sixth spacewalk for Chiao and the second for Sharipov.

Together they have amassed a total of nine hours and 58 minutes of spacewalk time during the two Expedition 10 spacewalks. Including today's event, ISS astronauts have spent 358 hours and 15 minutes working outside the space station. About 181 hours of that time is spread across 33 spacewalks staged from the ISS itself, NASA officials said.

The Expedition 10 crew currently has less than a month of on-orbit mission time remaining, with Chiao and Sharipov expecting to return to Earth on April 25.

• Complete Coverage: ISS Expedition 10