LE BOURGET, France—Ukrainian rocket specialist Yuzhnoye State Design Office is under a tight deadline from Orbital ATK to make the U.S. company’s Antares core stage compatible with the new RD-181 engine chosen to replace modified Russian NK-33s implicated in an October 2014 launch failure.

As developer and producer of the Antares core stage, Yuzhnoye is working toward a March 2016 Antares launch, which is expected to carry Orbital ATK’s Cygnus cargo vessel to the International Space Station (ISS) under a $1.9 billion fixed-price agreement with NASA to haul 20,000 kg (44,000 lb.) to the orbiting outpost by the end of 2017.

However, Yuzhnoye President and Chief Technology Officer Alexander Degtyarev says there are other modifications that could be made to the core stage to double Antares performance, offering the potential for Orbital ATK to meet NASA’s requirement with fewer launches.

Yuzhnoye, which builds rocket engines as well as stages, also has proposed a new liquid main-stage engine for Antares in the event that Orbital ATK decides to move off the RD-181 in the future.

Degtyarev says the core-stage engine, in development for Ukraine’s new Mayak family of liquid-fueled launchers, could also replace the Russian RD-180 that currently powers the United Launch Alliance (ULA) Atlas 5.

“The engine that we are developing for ourselves fits perfectly into American projects such as the Atlas 5, where they use the RD-180,” he said.

Such a shift in hardware could help dispel concerns among U.S. lawmakers over the nation’s continued reliance on Russian-made engines for access to space. However, the new powerplant would require additional investment for the core stage to be ready by 2019, by which time Orbital hopes to be supporting resupply missions to the ISS under a follow-on commercial-cargo contract with NASA.

Degtyarev says Yuzhnoye could support production of the Antares core stage and engines in the U.S., though he says development and maturity would be less costly in Ukraine.

In addition to Antares, Yuzhnoye has been working with Brazil to develop the Alcantara launch site to support Ukraine’s new Cyclone 4 rocket. He said that while the program may appear to be on hold, the treaty signed between the two governments has not been renounced by either party and he remains cautiously optimistic the Alcantara project could be restarted.

As for Yuzhnoye itself, Degtyarev says despite ongoing unrest in eastern Ukraine—where Yuzhnoye is headquartered—over the past five years the company’s workload had increased dramatically, though employment has not kept pace.

“This is a great company but this increase in personnel is a reflection of how much work we have, and we need people to support this level of workload,” he said.

In the meantime, Degtyarev says the company is investing in its future with new research and technology facilities and production tooling. But he said the company has not been able to take full advantage of the sharp decline in the Ukrainian hryvnia, compared to the other currencies, which makes Ukrainian products more attractive for export, but which has been largely wiped out by high inflation there.