Cygnus arrival at ISS
The International Space Station's robotic arm prepares to grapple the Cygnus cargo spacecraft as it arrives at the station Dec. 9, in this image taken by NASA astronaut Scott Kelly. Credit: NASA

WASHINGTON — As the first Cygnus mission launched on an Atlas rocket arrived at the International Space Station, Orbital ATK was already looking ahead to the second such mission, as well as resuming flights in 2016 of an updated version of the company’s own Antares launch vehicle.

The Cygnus spacecraft, flying a mission designated OA-4, arrived at the ISS early Dec. 9, two and a half days after its launch from Cape Canaveral, Florida. The station’s robotic arm grappled the spacecraft and berthed it to the Unity module, where it will remain until January.

Cygnus brought to the station more than 3,500 kilograms of cargo, such as crew supplies, space parts for the station, and experiments that include satellites that will later be deployed from the ISS. That is the most cargo ferried to the station since commercial cargo missions by Orbital and SpaceX began in 2012.

That heavier payload was enabled by Orbital’s decision a year ago to launch a Cygnus on a United Launch Alliance Atlas 5 while working to replace the first stage engines on the Antares rocket that caused an October 2014 launch failure that destroyed another Cygnus spacecraft bound for the station.

“Our goal from the beginning was that we wanted to get back to delivering cargo,” said Frank DeMauro, a vice president of Orbital ATK’s Space Systems Group who manages the Cygnus program, in a Dec. 3 interview at NASA’s Kennedy Space Center. “The two main parts of the goal were new main engines for Antares and, in the meantime, get Cygnus flying as soon as possible.”

While the contract for the Atlas launch of Cygnus announced last year was originally seen as a one-time deal, the companies announced in August a deal for a second Atlas launch of Cygnus, scheduled for March. “A slot opened up, NASA needed more cargo, and they were interested in taking advantage of that little bit of more cargo we could do on ULA,” DeMauro said.

Components of the Cygnus spacecraft for that next mission, OA-6, will start arriving at KSC in January for a launch tentatively scheduled for March 10. DeMauro said he doesn’t expect many changes to the processing flow for that spacecraft based on the experience preparing for the OA-4 mission.

“Off the top of my head, we can’t think of anything of any significance that we would want to change,” he said. There will be a formal “lessons learned” review with ULA and KSC officials later in December, he added, “and we’ll find some thing to improve the process. But my sense of things is that those will be relatively minor.”

The other part of that effort, replacing the engines on Antares, is also going well. “Overall, when you look at all the big changes that had to come together, that all went close to plan,” said Mike Pinkston, vice president and general manager of the Antares program at Orbital ATK, in a Dec. 3 interview.

Those big changes included replacing the AJ-26 engines previously used on the first stage of Antares with new RD-181 engines provided by Russian company NPO Energomash. That engine replacement did require some changes to the rocket as well as the launch pad at the Mid-Atlantic Regional Spaceport at Wallops Island, Virginia, work that Pinkston said was on schedule or already complete.

Orbital ATK currently plans to complete installation of the first set of RD-181 engines in an Antares first stage by February, with a static fire test on the pad at Wallops planned for early March. A successful test would clear the way for Antares launches of Cygnus spacecraft to resume in late May.

The remaining cargo missions under Orbital ATK’s current Commercial Resupply Services (CRS) contract with NASA, which runs through the OA-10 mission in early 2018, will launch on the upgraded Antares. NASA, meanwhile, has delayed awards for follow-on commercial cargo contracts, known as CRS-2, several times, most recently until as late as the end of January.

Those delays have not had a major effect on Orbital ATK’s long-term planning, according to DeMauro. “We’ve got a good hardware flow” to support the current missions under contract, he said. “The supply chain is established and moving along very nicely.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...