HOUSTON — Orbital Sciences has satisfied its Commercial Orbital Transportation Systems program requirements with a successful rendezvous of the Cygnus resupply capsule with the International Space Station and is cleared to march ahead with plans to initiate a $1.9 billion, eight-flight Commercial Resupply Services contract in December, Alan Lindenmoyer, NASA’s COTS program manager, said Sept. 29.

The first CRS flight is tentatively scheduled to lift off from the Mid-Atlantic Regional Spaceport in Virginia on Dec. 8.

For its part, Orbital plans 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 two to three-day baseline rendezvous trajectory to one day over the early CRS flights, said Frank Culbertson, Orbital’s executive vice president.

The two men spoke after the unpiloted Cygnus shook off a GPS navigation software mismatch issue with the space station that prevented a planned Sept. 22 rendezvous. The commercial freighter approached ahead of schedule on Sept. 29 for a robot arm capture by ISS astronauts Luca Parmitano, of the European Space Agency, and Karen Nyberg, of NASA, at 7 a.m. EDT. They completed the operation by commanding the Canadian robot 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 at 8:44 a.m. EDT, again ahead of schedule.

“They are good to go,” Lindenmoyer said. “The station has a spot ready for them in December. We’re getting the cargo ready to ship out. They’ve demonstrated a system that certainly can deliver. There will be no delays in proceeding toward the next mission.”

The supply ship, which was named for former NASA astronaut and Orbital executive G. David Low, was opened by the ISS crew early Sept. 30 (about 6 a.m. EDT). Cygnus will remain berthed until Oct. 22, and then depart with trash for a destructive re-entry into the Earth’s atmosphere.

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 February 2008 COTS program agreement, a qualifier to begin the CRS contract activities agreed to 10 months later, in December 2008.

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.

The original rendezvous schedule was postponed by 24 hr. and then until Sept. 29 to await the Sept. 25 launch and docking of Russia’s Soyuz TMA-10M with three new ISS crewmembers.

During the delay, Orbital fashioned a one-line software change that was uplinked and verified, allowing Cygnus to march through the final milestones during the last 10 hr. of the rendezvous. They included a successful command exchange from the ISS crew in which Cygnus was instructed to advance from a 250-meter hold point below the station to a separation of 230 meters, where it held for several minutes.