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.
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