Orbital Sciences Corp. has enough hardware on hand for the 10 commercial cargo missions it has contracted with NASA, and is already looking ahead to the day when it runs out of the surplus Soviet-era Russian engines it uses to power its new Antares launch vehicle.

The Dulles, Va.-based company is on the way to completing its second NASA mission with the safe launch Wednesday of its second and final demonstration mission with the Antares, this one carrying pressurized cargo to the International Space Station in the first full-up Cygnus cargo vehicle to fly.

If all goes well, and the Cygnus is able to demonstrate safe handling before reaching the ISS on Sunday morning, Orbital will be ready as early as Dec. 8-21 to begin fulfilling its eight-flight, $1.9 billion Commercial Resupply Service (CRS) to deliver bulk food, clothing and equipment to the station. The mission launched Wednesday completes the company’s Commercial Orbital Transportation Services (COTS) spacecraft-development agreement with NASA. It carries about 700 kg. of supplies, while early CRS flights will be able to handle as much as 2,000 kg of pressurized cargo, and an enhanced Cygnus would have a 2,700-kg capability.

Frank Culbertson, Orbital executive vice president, told reporters here after the Sept. 18 launch that Aerojet has another 16 AJ-26 engines in stock beyond the 20 Orbital has under subcontract for its NASA COTS and CRS missions. Aerojet modified the surplus Russian Nk-33 engines for the Antares role, and Orbital hopes to use them to meet the launch services market originally carried by the Delta II medium-lift launch vehicle, in addition to the NASA contracts that expire in 2016.

Once the old Russian engines run out, Culbertson said, Orbital has plans to find a replacement that will enable it to continue flying Antares.

“We’re looking at what the options are, who has engines that might be compatible and what’s available and how long would it take to develop and/or order them,” Culbertson said. “So we’ve got a very active effort going on.”

That effort includes discussions with “everybody who says they make an engine,” he said. “We know that sometime after 2016 we need to start looking at other alternatives.”

Meanwhile, Orbital controllers were off to a good start on the COTS demonstration. Culbertson said the Antares placed the Cygnus in a 289-by-257-km orbit, slightly above targets. The solar arrays deployed and began providing electrical power, and all valves opened to pressurize the propulsion system that will be used to pursue the ISS, which was over the Indian Ocean at the 10:58 a.m. EDT liftoff from the Eastern Shore of Virginia.

After a series of thruster burns to raise the orbit toward the station, the controllers plan a demonstration of the Cygnus’ ability to navigate using the Global Positioning System. Culbertson said the vehicle will approach the station and back away twice to demonstrate safe handling before going into the final “R-bar” approach from directly below it. The vehicle is scheduled to hold itself autonomously at a range of 250 meters before moving in close enough for station crewmembers working in the cupola to grapple it with the robotic arm and attach it to the nadir common berthing mechanism on Node 2.

The crew will open the hatch, unload the cargo and begin filling the vehicle with trash and unneeded gear that will ride to a destructive re-entry over the South Pacific east of New Zealand after about a month at the station.