An Antares rocket, one of two launchers developed with NASA backing to fly cargo capsules to the International Space Station, blasted off on its debut mission on Sunday, successfully depositing a dummy spacecraft into orbit.

Launch from a new commercial spaceport on Wallops Islands, Virginia, had been delayed from last week by a technical problem and two days of bad weather.

By Sunday, the skies had cleared and the 13-story rocket — the biggest ever to fly from the Wallops Flight Facility — lifted off its seaside launch pad precisely at 5 p.m. EDT.

An onboard camera showed the rocket riding a bright pillar of flame  as it hurtled over the Atlantic Ocean, heading toward an orbit 158 miles above Earth.

With the 4-ton dummy Cygnus capsule safely deposited into orbit, the Orbital Sciences mission control team broke into cheers and applause. They will regroup for a second and final Antares test flight slated for late June or early July when a real Cygnus capsule will attempt to fly itself to the station.

NASA hired Orbital Sciences and startup Space Exploration Technologies (SpaceX) to fly cargo to the station following the retirement of the space shuttles in 2011.

SpaceX completed three test flights and last year began the first of 12 supply runs to the station under a $1.6 billion contract.  NASA also contributed $396 million toward development and testing of the company’s Falcon 9 rocket and Dragon cargo capsule.

Orbital has one more test flight under its $288 million development contract before it is clear to begin the first of eight planned cargo runs under a $1.9-billion NASA contract. (Orbital’s Cygnus capsule is larger and can carry more cargo than SpaceX’s Dragon, hence the price difference.)

“It’s been a long slog,” NASA administrator Charlie Bolden told the Orbital Sciences launch team after the mission. “It’s absolutely incredible what this team has done.”

NASA radioed the space station crew about the successful test flight.

 “Wahoo, that’s super, that’s great news,” said station commander Chris Hadfield. “Good for them. Congratulations to all concerned. That bodes well for all of our futures.”

The dummy capsule is expected to remain in orbit for about two weeks before it will be pulled back into the atmosphere by Earth’s gravity and incinerate.