Orbital Sciences Corp. will begin fulfilling its $1.9 billion cargo resupply contract as early as December, after satisfying its Commercial Orbital Transportation Systems (COTS) program requirements with a successful berthing of the Cygnus resupply capsule with the International Space Station (ISS).

The first of Orbital's eight Commercial Resupply Services (CRS) missions is tentatively scheduled to lift off from the Mid-Atlantic Regional Spaceport in Virginia on Dec. 8, says Alan Lindenmoyer, COTS program manager.

Orbital intends to step up its mass per mission to 1.5-2 tons on the next three CRS missions, then 2.5 tons on the final deliveries. The Dulles, Va.-based company also plans to reduce the 2-3-day baseline rendezvous trajectory to one day over the early CRS flights, according to Frank Culbertson, Orbital's executive vice president.

Cygnus shook off a GPS navigation-software mismatch with the ISS that prevented a Sept. 22 rendezvous, and approached instead on Sept. 29 for a robotic-arm capture by ISS astronauts Luca Parmitano of the European Space Agency and NASA's Karen Nyberg.

They completed the operation by commanding the Canadian arm to place Cygnus and its 1,543-lb. non-critical cargo of crew provisions and science equipment at the U.S. segment Harmony berthing port, managing to get ahead of schedule for the task.

“They've demonstrated a system that certainly can deliver,” says Lindenmoyer. “There will be no delays in proceeding toward the next mission.”

Cygnus was launched atop an Orbital two-stage Antares rocket on Sept. 18 on the final demonstration mission flown under the company's $288 million COTS agreement, a qualifier to begin the CRS contract activities. It will remain berthed until Oct. 22, and then depart with trash for a destructive reentry into the Earth's atmosphere.

Orbital now joins SpaceX, of Hawthorne, Calif., in NASA's CRS stable to take on an ISS resupply role, filled by NASA's shuttle fleet until the winged orbiters were retired in 2011. SpaceX already has started its 12-flight, $1.6 billion CRS work.