Orbital Sciences successfully launched its resupply mission to the International Space Station on Thursday at 1:07 p.m. EST after weeks of delay.

The aerospace firm's unmanned Antares rocket blasted off from NASA's Wallops flight Facility in Virginia, carrying with it the Cygnus cargo capsule, which is scheduled to rendezvous with the space station Sunday morning.

At the time of launch, the station was located above the Atlantic Ocean, speeding near the Brazilian coastline at an altitude of 260 miles. 

"Our team has put in a lot of hard work to get to the point of performing regular ISS cargo delivery trips for NASA," Orbital's President and CEO David Thompson said following the launch. "It's an exciting day for all of us and I'm looking forward to completing this and our future CRS missions safely and successfully for our NASA customer."

The shipment of nearly 3,000 pounds of cargo was originally planned to leave Dec. 18. The launch was delayed on Dec. 11 when a pump module on one of the station's two external cooling pipes shut down upon reaching its preset temperature limit. Two spacewalks were needed to fix the problem, each carried out by NASA crew members Mike Hopkins and Rick Mastracchio. The first, on Dec. 23, removed the module while the second, performed two days later, replaced it.

Rescheduled for Jan. 7, the launch was delayed once more when the Sun unleashed a X1.2-class solar flare the same day. The flare was associated with an Earth-directed coronal mass ejection - an event that can hurl billions of tons of particles into space. Although these particles cannot travel through the Earth's atmosphere to harm humans, they can affect electronic systems and satellites. Given the radiation levels at the time, officials delayed the launch, unsure Antares' systems could withstand the onslaught.

Once complete, the mission will be Orbital's first following a successful trial carried out in September as part of a $1.9 billion contract with NASA.