Orbital Sciences Corporation's unmanned Cygnus cargo ship on Sunday arrived at the International Space Station on the company's first regular supply mission to the research outpost.

Cygnus is delivering 2,780 pounds (1,260 kilograms) of supplies to the space station including hardware, food and equipment, which astronauts will use to carry out studies on everything from ant behavior to antibiotic drug resistance.

The capsule officially berthed with the space station at 1305 GMT, nearly two hours after a robotic arm reached out and grabbed the incoming cargo carrier, according to the US space agency NASA's television network.

US astronaut Mike Hopkins and his Japanese colleague Koichi Wakata operated the space lab's 57-foot (17-meter) Canadian-made mechanical arm, known as the Canadarm, which connected with Cygnus at 1108 GMT.

"Basically capturing something that is free-floating in space right next to you going so fast... with so much at stake, that is the tricky part," said astronaut Cady Coleman, who narrated the capture from Earth for NASA TV.

The crew used the robotic arm to guide Cygnus to its berthing port on the Earth-facing side of the Harmony node for the installation process, according to NASA.

The rendezvous -- the term given to the crucial moment when the arm grasps the capsule -- "goes by pretty fast," said Coleman.

"You train and train and you practice and practice, and that's what it comes down to."

The mission is the first official resupply trip for Orbital's cargo ship, coming on the heels of the company's successful demonstration flight and berthing at the ISS in September.

Orbital on Sunday expressed elation over how smoothly the maneuver went.

Its maiden mission under its contract with NASA "was flawlessly executed... from the picture-perfect launch... to the rendezvous, capture and berthing at the space station this morning," company CEO David Thompson said in a statement.

"Our whole team has performed at a very high level for our NASA customer and I am very proud of their extraordinary efforts."

According to NASA, a hatch will be opened later in the day or on Monday to begin unloading the supplies.

The spacecraft will eventually be packed with disposable items. It will remain at the station until mid-February.

After Cygnus detaches, it will burn up on re-entry to Earth's atmosphere and will disintegrate over the Pacific Ocean.

The commercial space company SpaceX is due to send its Dragon capsule to the ISS shortly afterward for another cargo mission.

Both Orbital and SpaceX have contracts with NASA worth more than a billion dollars each to supply the space station over multiple trips, restoring US access to the ISS after the retirement of the space shuttle program in 2011.

California-based SpaceX, owned by Internet entrepreneur Elon Musk, became the first private company to reach the space station with its Dragon capsule in 2012.

Cygnus's berthing at the ISS marks the fifth mooring of a private vessel at the space station in two years.

NASA has announced that the life of the $100 billion International Space Station will be extended by an additional four years, or until 2024.

The space lab serves a global science collaborative and was launched in 1998. It had been expected to stay in operation until 2020.

Partnering agencies are NASA, the Russian federal space agency Roscosmos, the Canadian Space Agency, the European Space Agency and the Japan Aerospace Exploration Agency.