The number of private cargo ships in space just doubled.

A rocket from Orbital Sciences successfully blasted off Wednesday at 10:58 a.m. EST, carrying the second private cargo craft ever on a supply mission to the International Space Station.

"Go Antares, go Cygnus," mission control whispered in the moments before the Antares rocket launched from NASA's Wallops Island Facility in Virginia, carrying the Cygnus craft and 1,300 pounds of food, clothes and other items -- including chocolate for the astronauts aboard the station.

The rocket quickly reached 10,000 miles per hour, ultimately topping 16,700 miles per hour before slowing a touch on its way to a a planned Sunday delivery.

If this latest mission succeeds, Orbital Sciences will start launching more Cygnus cargo ships under a $1.9 billion contract with NASA. The commercial effort began more than five years ago.

More On This...

The California-based SpaceX is already shipping goods from Cape Canaveral, Fla., under a separate $1.6 billion contract. Its first trip was in May last year.

Formally known as Space Exploration Technologies Corp., the company founded by billionaire Elon Musk of PayPal fame has the only unmanned vessel capable of returning space station items to Earth. The SpaceX Dragon parachutes into the Pacific off the Southern California coast.

The smaller Cygnus capsule from Orbital Sciences Corp. will be filled with space station trash following its month-long visit and burn up upon descent. That's the same fate as the Russian, European and Japanese supply ships.

NASA is looking to private U.S. industry to keep the space station stocked in the post-shuttle era. It's also putting seed money into SpaceX and other companies for development of a manned capsule. That's still years away, so NASA will continue to buy rides for its astronauts on Russian rockets. One American will be aboard the Soyuz capsule due to take off next week from Kazakhstan, along with two Russians. The trio will double the station population to its normal six.

Wallops was in the spotlight earlier this month. On Sept. 6, NASA launched a robotic explorer, named LADEE, to the moon. It's still en route. Orbital Sciences provided the Minotaur V rocket used in the moonshot, which was widely seen in the night sky along the East Coast. Wednesday's daytime launch won't be nearly as visible.

Frank Culbertson, the company's executive vice president and a former space shuttle commander, said Tuesday that the excitement level is high.

"This is one of the most exciting things that is happening in the middle of a very exiting month for Orbital, for NASA and for space programs around the world," Culbertson said at a news conference, referring to all the various launches and re-entries.

"We're happy to be the focus of attention for today and tomorrow," he added. "Launching Antares ... is going to be a major step in our program."

The Associated Press contributed to this report.