Japan's
first unmanned space cargo ship cast off from the International Space Station
Friday as it nears the end of a successful maiden voyage.
Astronauts
aboard the station used the outpost's robotic arm to pluck the spacecraft, called
the H-2 Transfer Vehicle 1 (HTV-1), free from an Earth-facing mooring and let
it go at about 1:30 p.m. EDT (1730 GMT).
The HTV-1
is the first in a new line of Japanese
space freighters to haul tons of supplies for astronauts aboard the space
station. It is the latest addition to an international flotilla of unmanned
space cargo ships for the station that includes Russian and European vehicles.
But the
HTV-1 is currently the only freighter capable of delivering cargo for use
inside the station, as well as new experiments and other equipment for the
outpost's exterior. It is due to fire its thrusters on Sunday in order to begin
an intentional death plunge into Earth's atmosphere over the Pacific Ocean.
"We'd like
to thank everybody across the planet for this beautiful vehicle," NASA
astronaut Nicole Stott radioed Mission Control as HTV-1 left the station's
vicinity. "It was pretty much flawless from beginning to end."
NASA delayed
the departure of HTV-1 from the station by one orbit - about 90 minutes -
in order to be sure a piece of Russian space junk would not pose a risk to the
spacecraft. The debris, part of a defunct Russian satellite, posed no danger to
the space station and its crew, but could have posed a threat to the HTV-1 once
it entered a different orbit later today, NASA officials said.
The Japan
Aerospace Exploration Agency (JAXA) launched
the HTV-1 in early September using its brand-new H-2B rocket. Both
spacecraft functioned perfectly during the spaceflight debut. A mission control
center in Tsukuba, Japan, watched over HTV-1's weeklong trek to the space
station.
The
gleaming HTV-1 is a gold-colored cylinder about 33 feet (10 meters) long, 14
feet (4.4 meters) wide and covered in solar panels attached to its curved hull.
It is capable of hauling up to 6 tons of cargo to the space station, but
HTV-1 carried about 4 1/2 tons of supplies on its maiden flight, NASA officials
have said.
HTV-1 arrived
at the space station on Sept. 17, when Stott and her five crewmates plucked it
from space using the station's robotic arm. They packed it with nearly 1,600 pounds (728 kg) of trash before discarding the disposable spacecraft Friday.
Unlike
Russian and European cargo ships, which can fly themselves up to the space
station autonomously, HTV-1 is designed to be grappled by the station's arm.
NASA hopes to use a similar method for securing future commercial cargo ships
built in the United States.
JAXA
officials said Japan spent about $220 million to build HTV-1, but the
spacecraft's development has cost an estimated $680 million since 1997. The
Japanese agency plans to build at least one new HTV a year, they added.
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