The roar of the rocket was followed by a sigh of relief.

On the evening of Oct. 17, an Orbital ATK Antares rocket lifted off from Virginia’s Mid-Atlantic Regional Spaceport, nearly two years after the previous Antares launch ended in an engine failure and explosion.

Nine minutes after liftoff, the reengineered rocket released into orbit its payload, a Cygnus cargo spacecraft on a mission to the International Space Station designated OA-5.

“It is great to be back,” said Frank Culbertson, president of Orbital ATK’s Space Systems Group, at a celebratory post-launch press conference at NASA’s Wallops Flight Facility. “It took a little longer than we thought it would. These things are always harder than you expect them to be in many ways, but it was done right.”

What was done right was the upgrade of the Antares rocket. With the AJ26 first-stage engine — a refurbished version of the NK-33 engine developed for the former Soviet Union’s N-1 moon rocket decades ago — implicated in the October 2014 accident, Orbital ATK decided not long afterwards to replace it with new RD-181 engines from Russian firm NPO Energomash.

While the RD-181 was billed as the closest to a “plug-and-play” replacement for the AJ26, it still required changes to the rocket to accommodate it. Mike Pinkston, Antares program vice president and general manager at Orbital ATK, said prior to the launch that those changes included modifications to the structure that transfer thrust loads from the engine, new control systems and increased instrumentation.

Those changes were tested with a static fire of the first stage on the pad at the end of May. “It was a very detailed, meticulous process,” he said, “but as evidenced by the stage test, we got it right and we’re ready to go.”

Orbital ATK felt confident enough to forego a test flight of the upgraded Antares before putting a Cygnus on it. “The first stage has been changed,” Culbertson said prior to launch, “but we understand those changes, and we feel like all those tests covered the risks people have been able to think of.”

That confidence was justified by the rocket’s performance, which Culbertson said was even better than expected. “Since it was the first flight of this configuration, we had fairly conservative estimates of what the results would be,” he said after the launch. “The engines did perform very well.”

That’s good news for both NASA and Orbital ATK. NASA is relying on Antares and Cygnus to help resupply the station, particularly at this moment. The Sept. 1 pad explosion of a SpaceX Falcon 9 will delay Dragon resupply flights for at least a few months: the next mission, which was scheduled for November, is now expected to slip to at least early 2017, depending on when the Falcon 9 is cleared to resume launches. Japan’s HTV cargo vehicle has also suffered delays, with an October mission now planned for early December.

Joel Montalbano, NASA’s deputy manager of the ISS program, said the agency addressed those other delays by adding cargo to this Cygnus. “We originally had some ballast that we were flying on this vehicle,” he said. “We’ve removed all that ballast and we’ve replaced it with crew supplies,” ranging from additional food and clothing to hardware for upgrading computers on the station.

An upgraded Antares now allows Orbital ATK to start thinking about other business for that vehicle. Since its inaugural test flight in April 2013, every Antares mission to date has carried, and every future launch currently under contract will carry, Cygnus cargo spacecraft for NASA.

“There’s nothing about the Antares rocket that makes it unique to the CRS missions,” Pinkston said, referring to the company’s Commercial Resupply Services contract from NASA. “We’ve got aspirations to market and sell it for other satellite operations, anything in the medium class.”

How strongly Orbital ATK has been following up on those aspirations isn’t clear. Some customers might require additional changes to Antares, such as a new upper stage, Pinkston acknowledged. “A lot of those applications would require development of an alternate upper stage capability,” he said. “We’ve got thoughts on that.”

Others, like some NASA science missions, might be able to use the Antares as-is. “I think in all cases a successful flight is going to be an entry requirement to any of that, so that’s why we’ve been squarely focused on the OA-5 mission,” he said before the launch.

Orbital ATK’s Cygnus team, meanwhile, has also been exploring additional uses for the cargo spacecraft. The company was one of six to receive a Next Space Technologies for Exploration Partnerships (NextSTEP) award from NASA in August. That contract will allow the company to continue studies of using Cygnus-derived spacecraft for a cislunar habitat that it started last year.

“We think Cygnus has all the building blocks in place to be able to be used as a habitation module or logistics module out beyond Earth orbit,” said Frank DeMauro, vice president for human space systems at Orbital ATK, in an Oct. 16 interview. In the new NextSTEP contract, he said, the company will develop a ground prototype of a Cygnus-derived habitation module.

He added that the company is exploring other applications of the Cygnus system. “We’re out looking at how we can use the Cygnus platform, primarily the service module, for other types of missions,” he said. That service module includes the power, propulsion, control and other key subsystems of the spacecraft, and DeMauro said it could be adapted for use by other, unspecified payloads.

The advantage of using the Cygnus service module, he said, is that it has demonstrated the ability to handle large payloads and operate safely in the vicinity of the space station. “In and of itself, the Cygnus service module has a lot of capability,” he said. Combined with the company’s other spacecraft experience, “you come up with a recipe for a very capable spacecraft than can be used for all sorts of purposes.”

Those potential Cygnus-derived spacecraft might be logical candidates for future Antares launches. “We are actually proposing the use of Cygnus for other applications in low Earth orbit,” Culbertson said. “Antares would continue to be the ideal launch vehicle for most of those missions.”

Yet, Culbertson was careful not to get too far ahead on potential future uses of Antares and Cygnus, given the company still has a backlog of ISS cargo missions to carry out for NASA. Asked at the post-launch press conference what was next for Cygnus and Antares, he had a simple answer: “Launch again.”

“We’ve got aspirations to market and sell it for other satellite operations, anything in the medium class.”


— Mike Pinkston