A Cygnus cargo ship began a long-delayed, three-day journey to the International Space Station on Sunday following a successful launch aboard Orbital Sciences Corp’s fourth Antares rocket.

The 13-story rocket blasted off at 12:52 p.m. EDT from the new Mid-Atlantic Regional Spaceport (MARS) at NASA’s Wallops Flight Facility on the Virginia coast.

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“It’s a very exciting day for us,” said Orbital Sciences vice president Frank Culbertson, a former astronaut who spent four months aboard the space station in 2001.

“I think we found the secret to getting people’s attention here on the eastern shore of Virginia, Maryland and Delaware, and that’s to launch on a Sunday in July,” Culbertson quipped. “There’s a lot of traffic out there right now.”

“It took a lot of effort for people to pull this off. We worked a lot of problems up to the last couple of months that had to be resolved. Even today, as we were working through the countdown, small things came up and people had to figure them out,” he said.

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The last-minute issues included sailboats encroaching in an area blocked off so that the rocket’s first stage could fall back into the water without posing a risk to mariners.

“The Coast Guard went out to try to turn them around – one of them didn’t want to turn around. I don’t think they believed them,” Culbertson said.

With the range clear, Orbital Sciences proceeded to launch its Antares rocket on its second operational mission for NASA. The booster previously made two test flights, including a practice run to the space station last September.

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The Cygnus capsule is due to reach the space station early Wednesday. Astronauts aboard the outpost will use the station’s robotic arm to snare the capsule from orbit and bolt it to a docking port on the Harmony connecting module.

The capsule carries more than 3,600 pounds of food, supplies, experiments and research equipment, including 28 Earth-imaging CubeSats for San Francisco-based Planet Labs. The small satellites will be deployed by a specially made CubeSat launcher set up in Japan’s Kibo laboratory module.

Once Cygnus is unpacked, it will be filled with trash and equipment no longer needed on the station. After about a month, Cygnus will be released back into space and re-enter the atmosphere for incineration.

Orbital Sciences is one of two companies hired by NASA after the space shuttles were retired to fly cargo to the station. The other company, SpaceX, made its third paid delivery in April. NASA is paying the companies a combined $3.5 billion for the station resupply missions.