BE-3

The BE-3 ("Blue Engine 3") is a LH2/LOX rocket engine developed by Blue Origin.
The engine began development in the early 2010s, and completed acceptance testing in early 2015. The engine is being used on the New Shepard suborbital rocket, for which test flights began in 2015.
The engine was under consideration by United Launch Alliance (ULA) for use in a new second stage, the Advanced Cryogenic Evolved Stage, in ULA's Vulcan orbital launch vehicle with first flight in the 2020s.
History.
The BE-3 follows the earliest rocket engine development efforts at Blue Origin in the 2000s. Blue Origin's first engine was a "simple, single-propellant engine" called the Blue Engine-1 (BE-1) which used peroxide propellant and generated only of thrust, and their second, the Blue Engine-2 (BE-2) which was a bipropellant engine using kerosene and peroxide, producing thrust.
In January 2013, the company announced the development of the Blue Engine-3 BE-3, a new liquid hydrogen/liquid oxygen (LH2/LOX) cryogenic engine. The engine was originally announced to produce thrust, with initial thrust chamber tests planned for mid-February 2013 at NASA Stennis. The thrust chamber tests were run sometime in 2013.
The BE-3 was successfully tested in late 2013 on a full-duration simulated suborbital burn, with coast phases and engine relights, "demonstrating deep throttle, full power, long-duration and reliable restart all in a single-test sequence." NASA has released a video of the test.
By December 2013, Blue Origin updated engine specifications following engine tests conducted on test stands at ground level, near sea level. This demonstrated that the engine could produce of thrust at full power, and could successfully throttle down to as low as for use in controlled vertical landings if needed for that purpose on particular launch vehicles. The final engine specifications, released in April 2015 following the full test phase, included a minimum thrust of , an even wider throttling capability by 20 percent than the preliminary numbers, while maintaining the previously released full power thrust spec.
, the engine had "demonstrated more than 160 starts and of operation at Blue Origin's test facility near Van Horn, Texas." Additional testing of the BE-3 was completed in 2014, with the engine "simulating a sub-scale booster suborbital mission duty cycle."
Test stand testing of the engine was completed by April 2015, with over 450 engine firings and a cumulative engine test time of over 500 minutes. Blue Origin stated it would make the first test flight of its "New Shepard" vehicle later in 2015.
In the event, Blue Origin made the first flight test of the engine on the "New Shepard" suborbital vehicle before the month was out, flying a boost profile to altitude on 29 April 2015.
, United Launch Alliance (ULA) is considering the BE-3 for use in a new second stage, the Advanced Cryogenic Evolved Stage (ACES), which is, , planned to become the primary upper stage for ULA's Vulcan orbital launch vehicle in the 2020s. The Vulcan is planned to begin orbital flights in 2019 with an existing Centaur upper stage, and is considering three engines from various manufacturers for the ACES stage which would putatively begin flight in 2023, with selection expected before 2019.
While development of a sea-level version of the engine was completed and fully qualified by early 2015, Blue Origin said then that they intend to develop a vacuum version of the engine to operate in space.
In January 2016, the US Air Force provided partial development funding to Orbital ATK to develop an extendable nozzle for the Blue Origin BE-3U.
Engine design.
The BE-3 uses a pump-fed engine design, with a combustion tap-off cycle to take a small amount of combustion gases from the main combustion chamber in order to power the engine turbopumps.
BE-3U.
For Blue Origin's orbital launch vehicle—New Glenn—Blue has developed an open expander cycle variant of the BE-3, the BE-3U, for use in upper stages. Two of these engines will be used to power New Glenn second stage. 
In November 2015, the engine was projected to have a vacuum thrust of .
Development had begun on the extendable nozzle for BE-3U by early 2016.
By August 2018, BE-3U engine development had proceeded, test engines built, and had accumulated over 700 seconds of test time, confirming performance assumptions in the design. In February 2019, Blue Origin updated the thrust of BE-3U as used on New Glenn to .
Technical specifications.
The performance of the sea-level version of the BE-3 include: