NATIONAL HARBOR, Md. — Development of Aerojet Rocketdyne’s new engine could be delayed without sufficient government funding, company executives said here Sept. 15.

Julie Van Kleeck, Aerojet Rocketdyne’s vice president for space and launch, said work on the AR1 engine is on track to have the engine certified by 2019, but that work could be delayed if the company does not win enough money in contracts the Air Force expects to award late this year.

Congress has given the U.S. Air Force a 2019 deadline for fielding an American-made propulsion system capable of ending the Defense Department’s dependence on the Russian-made RD-180 engine that powers United Launch Alliance’s Atlas 5 rocket.

To that end, the Air Force is expected to award as many as four contracts in the coming weeks worth a combined $160 million for new prototype rocket propulsions systems.

These awards, Van Kleeck said during a press conference during the annual Air Force Association technology expo here, “will show how serious they are about 2019.”

Aerojet Rocketdyne is developing the AR1 as a replacement for RD-180 main stage engine. While United Launch Alliance is supporting AR1 development, ULA has indicated that Blue Origin’s BE-4 engine is the leading candidate to replace the RD-180 and power Vulcan, ULA’s proposed Atlas 5 successor.

Meanwhile, Aerojet Rocketdyne officials declined to comment on reports about its $2 billion bid for ULA. It is widely assumed Aerojet Rocketdyne would drop the BE-4 for AR1 if it were to acquire ULA from Boeing and Lockheed Martin, ULA’s parent companies.