Orbital Sciences, one of two firms hired by NASA to fly cargo to the International Space Station after the space shuttles were retired, successfully launched its first supply ship on Thursday.
The company's Antares' rocket, carrying a cargo ship called Cygnus, blasted off from a commercial spaceport on Wallops Island, Virginia, at 1:07 p.m. EST, the first step of a 2.5-day journey to the station.
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Launch was delayed twice this week by weather issues; first by the frigid cold and then by an unusual space weather event - high radiation from a massive solar flare.
If all goes as planned, astronauts aboard the station will use the outpost's robotic arm to latch on to the capsule shortly after 6 a.m. EST on Sunday and dock it to a berthing port on the station's Harmony node.
The capsule is loaded with nearly 2,800 pounds of cargo, including science experiments, computers and supplies for the six-member, live-aboard station crew.
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The freighter also carries belated Christmas gifts, as the launch originally was planned for December. NASA delayed the flight when one of the station's cooling systems shut down and astronauts needed to conduct a pair of spacewalks to install a spare pump.
While fresh science experiments and food, including fruit, were replaced, the gifts stayed.
"We haven't changed them out for Valentine's cards," joked Orbital Sciences' Frank Culbertson, a former astronaut and station commander who now serves as the firm's executive vice president.
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Orbital Sciences and Space Exploration Technologies, which also flies cargo for NASA, plan to make up to six trips to the station this year.
Orbital Sciences, which has a $1.9 billion contract for nine flights, made a successful demonstration run to the station in September. SpaceX is preparing for its third cargo run on Feb. 22.