The uncontested launch site

Orbital ATK said a benefit of Antares over the Atlas V is launching from Wallops Island, Virginia, which has a less-crowded schedule than Kennedy Space Center, where SpaceX and United Launch Alliance also book launch slots.

"We like to call it our uncontested launch site," Patterson said.

The Wallops Flight Facility, as it is formally known, is the country's only NASA-operated launch range, and is not subject to Air Force oversight and coordination. Other than Orbital ATK Antares and Minotaur flights, the facility is best known for sounding rockets and balloon missions.

The facility is managed by NASA's Goddard Space Flight Center, and enjoyed strong political support from outgoing Maryland Senator Barbara Mikulski. A 2014 economic impact statement found the facility impacts the coastal region by more than $808 million annually, and Orbital ATK officials said a single Antares launch generates tourism revenue similar to the area's other big draw, the annual Chincoteague Pony Swim.

The plan all along: RD-181 engines

In my previous article exploring the future of Antares, I noted the rocket has yet to find a customer beyond NASA's ISS cargo program. Yet one of the reasons Orbital ATK was selected for the program was to stimulate the U.S. launch market.

Antares debuted in 2013 sporting a pair of Aerojet AJ-26 engines, which were refurbished powerplants left over from the Soviet Union's N-1 moon rocket program. After the 2014 launch accident, in which an AJ-26 engine was implicated, Orbital ATK quickly announced a plan to switch to a more modern Russian engine: the RD-181.

Company officials told me upgrading to the RD-181 was actually the plan all along—the accident merely accelerated the process.

In 2012, Orbital ATK signed a separate NASA contract, known as NLS-II, to place Antares on the menu of possible NASA science mission launchers. Bowman and Patterson said that at the time of the accident—the rocket's fifth flight—Antares had just gained enough credibility to become a viable option for other customers.

That momentum was derailed, and the engine swap set the rocket’s ambitions back further, because a re-flight was necessary under the NLS-II contract. After last year's successful return-to-flight mission, Antares is available for NASA science missions once again.

"We do now have some options we are working toward that are non-cargo," Patterson said.

Antares versus Atlas

If Antares flights are cheaper, why would NASA choose an Atlas V for Cygnus flights?

At the moment, the reason is cargo capacity. The Atlas V, which launches Cygnus using the rocket's lightest-lift variant, the 401, allows Cygnus to carry up to 3,513 kilograms. Antares, at the moment, can only lift 3,200 kilograms.

Orbital ATK said that won't be the case much longer. The RD-181 engines offers a 13 percent thrust increase over the AJ-26 engines, and the rocket performed better than expected during its return-to-flight mission. This will allow the company to shed what it calls "contingency margin."

When combined with a CASTOR 30 XL upper stage, Antares in its new configuration is capable of matching the Atlas V 401.

"For OA-11 (the final CRS-1 flight), we will be increasing the payload capability to 3500 kilograms," Patterson said.

Through at least 2024, then, Orbital ATK expects to launch a lot of ISS cargo flights from Wallops Island.

"ULA has been a great partner, and if NASA wants us to launch Cygnus on an Atlas again, we will be happy to do so," Bowman said. "However, our baseline plan is to launch on Antares for CRS-2, unless otherwise asked or directed."