Workers roll out the first BE-4 engine in the Blue Origin Factory in Washington StateUnited Launch Alliance has decided that Blue Origin’s BE-4 rocket engine will be the propulsion of choice for its new Vulcan launch platform. The BE-4 has been under development since 2011 and has been vying for the contract for the last four years, completing with Aerojet Rocketdyne’s AR1.

The BE-4 will end the ULA’s reliance on the purchase of Russian manufactured engines, which Congress restricted to just 18 RD-180 engines through 2022. The new rocket engine will also serve as the main engines for the New Glenn platform, which Blue Origin is developing privately.

The Vulcan will replace two of ULA’s current rockets, the Atlas V and Delta IV, which have been workhorses ULA and its customers. It represents a major shift away from single-use rockets and marks Blue Origin’s entry into the world of military contracts. Though Aerojet lost the main engine contract, its smaller RL10 engine will still power the second stage of Vulcan.

Jeff Bezos, CEO of Amazon, has been spending approximately $1 billion a year on Blue Origin, which is headquartered in Kent, Washington, a few miles south of Seattle.

For its part, United Launch Alliance, which is a partnership between Boeing and Lockheed, is the primary contractor for the vast majority of military launches, especially national security missions. SpaceX has been nipping at their heels recently with their Falcon 9 and Falcon Heavy platforms, but the new Vulcan rocket should keep ULA competitive for years to come.

Read more in The Verge.