The United Launch Alliance (ULA) announced today that it has selected Blue Origin’s BE-4 engine for its new Vulcan rocket over Aerojet Rocketdyne’s AR1. ULA and Blue Origin announced a partnership four years ago, but the competition with Aerojet Rocketdyne has taken this long to reach its conclusion. ULA will use a different Aerojet Rocketdyne engine for the Vulcan’s Centaur upper stage, however.

The decision was announced by press release and tweets today.

Big win for @BlueOrigin today! And a big thank you to @ulalaunch for choosing our BE-4 engine. Excited to be a part of Vulcan’s mission to space. #21stCenturyEngine #AllAmericanEngine #GradatimFerociter https://t.co/K0Szt3jesi — Jeff Bezos (@JeffBezos) September 27, 2018

Video of tests of the BE-4 (Blue Engine-4), which uses liquid oxygen (LOX)/Liquefied Natural Gas (LNG) as propellant, is posted on YouTube. LNG is a form of methane so it is sometimes referred to as a LOX/methane engine.

Amazon.com billionaire Jeff Bezos, who founded, funds and owns Blue Origin, and the company’s president, Bob Smith, thanked ULA for choosing the BE-4. Smith added they look forward to building the engine in Huntsville, AL. Alabama is home not only to ULA’s production facility in Decatur, but to Sen. Richard Shelby, the powerful chairman of the Senate Appropriations Committee. He also tweeted his congratulations.

Big announcement! @BlueOrigin & @ULALaunch will now be partnering to provide affordable, reliable access to space with an American-made rocket built in #Alabama. Looking forward to the groundbreaking of its new facility in Cummings Research Park. #MadeinAL https://t.co/yDC5lfubHt — Richard Shelby (@SenShelby) September 27, 2018

Vulcan will replace ULA’s Atlas V rocket, which is powered by Russia’s RD-180 engines. ULA decided to build a new rocket after a long, contentious congressional debate led by the late Sen. John McCain to end U.S. dependence on Russia for launching national security payloads into space. By law, RD-180s may only be procured through the end of 2022.

Many national security satellites are launched on Atlas V, as are NASA payloads. In addition to robotic spacecraft, Boeing will use it to launch its CST-100 Starliner commercial crew vehicles to the International Space Station. They will transition to Vulcan or other rockets as the Atlas V is phased out. Vulcan will also replace ULA’s Delta IV.

ULA is a 50-50 joint venture between Boeing and Lockheed Martin.

ULA said today it anticipates the first Vulcan launch in mid-2020. Several successful launches are required before a rocket is certified by the Air Force to launch the most critical national security satellites. The goal is to get Vulcan certified before the RD-180s run out.

Each Vulcan will use two BE-4 engines, each generating 550,000 pounds of sea level thrust. Paired with a Centaur upper stage, powered by Aerojet Rocketdyne RL10 engines, and Northrop Grumman solid rocket boosters, Vulcan will be able to place 56,000 pounds into low Earth orbit (LEO), 33,000 pounds into Geostationary Transfer Orbit (GEO), or 16,000 pounds into Geostationary Orbit (GEO).

ULA President Tory Bruno said “Our new rocket will be superior in reliability, cost and capability — one system for all missions. We have been working closely with the U.S. Air Force, and our certification plan is in place.”

Bruno and Bezos announced their partnership in 2014, but the BE-4 versus AR1 competition took until now to be resolved. Aerojet Rocketdyne tweeted that it remains committed to development of the AR1.