Tory Bruno, president and chief executive of United Launch Alliance, testifies before the House Armed Services strategic forces subcommittee June 27.

WASHINGTON – Blue Origin continues to have the upper hand in a competition with Aerojet Rocketdyne to build a new engine for United Launch Alliance’s next-generation rocket, ULA chief executive Tory Bruno said June 27.

Testifying before the U.S. House Armed Services committee strategic forces subcommittee, Bruno said Blue Origin’s BE-4 engine development program is 16 months ahead of Aerojet Rocketdyne’s AR1 effort.

Congress mandated last year that the Defense Department develop a kerosene-fueled main rocket engine to replace the Russian RD-180, which powers the main stage of the ULA’s Atlas 5 rocket, by 2019. The Atlas 5 launches a majority of the Defense Department’s national security satellites.

ULA announced in September that its first choice for a replacement is the BE-4, a liquid-natural-gas fueled engine that cannot be used on the Atlas 5 as currently designed. Blue Origin of Kent, Washington, the secretive company owned by founder Jeff Bezos, is developing that engine using its own funds.

Sacramento, California-based Aerojet Rocketdyne has since stepped up its internal investment in the AR1, components of which have been developed in part with government funding. ULA has a contract with Aerojet to retain the AR1 as a backup in case the BE-4 effort falters.

ULA expects to make a final decision on which engine to pursue in late 2016. Unlike the AR1, which is designed to fit into the Atlas 5, the BE-4 would require ULA to develop a new rocket — essentially an Atlas 5 with a new first stage — called Vulcan.

“[The AR1] is at present 16 months behind the [BE-4] engine simply because it started later and it does require significant government funding in order to continue,” Bruno told the subcommittee during a hearing. “Both programs are currently on plan. They are meeting their program and technical milestones.”

The Air Force has raised doubts that it can meet Congress’ 2019 deadline for fielding a new U.S.-built engine. Aerojet Rocketdyne and Blue Origin executives are more optimistic.

“Aerojet Rocketdyne is on-track to deliver our AR1 engine in 2019,” Julie Van Kleeck, vice president of advanced space and launch systems, said in a July 1 email to SpaceNews. “We are slated to test our first development engine in 2017, followed by additional testing in 2018 to provide a certified engine in 2019.”

Rob Meyerson, president of Blue Origin, noted in written testimony that the BE-4 has been in development for more than three years.

“Most importantly, it is on schedule to be qualified for flight in 2017 and ready to support the first Vulcan flight in 2019, two years ahead of any alternatives,” he said.

Congress appropriated $220 million this year for RD-180 replacement work, and the Air Force is planning to start awarding engine technology development contracts this year. Among the companies expected to bid, at least for a piece of the funding, are Aerojet Rocketdyne and Orbital ATK of Dulles,Virginia.

SpaceX, the Hawthorne, California, company whose Falcon 9 rocket was certified in June to launch U.S. military payloads, has not indicated whether it will compete for a share of the money.

Key members of Congress and the Air Force, meanwhile, differ on the strategy for ending U.S. reliance on Russian engine technology. These lawmakers want the Air Force to proceed immediately on a direct replacement for the RD-180, while the service plans to invest in various rocket and propulsion technologies.

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.