BE-4
The Blue Engine 4 or BE-4 is an oxygen-rich liquefied-natural-gas-fueled staged-combustion rocket engine under development by Blue Origin. The BE-4 is being developed with private and public funding. The engine has been designed to produce of thrust at sea level. It was initially planned for the engine to be used exclusively on a Blue Origin proprietary launch vehicle New Glenn, the company's first orbital rocket. However, it was announced in 2014 that the engine would also be used on the United Launch Alliance (ULA) Vulcan Centaur launch vehicle, the successor to the Atlas  V launch vehicle. Final engine selection by ULA happened in September 2018. Although previously planned to fly as early as 2019, the first flight test of the new engine is now expected no earlier than 2022 on the Vulcan rocket. The engine is running four years behind , and Blue has experienced a number of problems, both technical and managerial, with the engine development program, leaving the engine still not yet flight-qualified. While flight engines have not been delivered, pathfinder engines are currently undergoing testing at ULA facilities, and flight engines are being built. History. Following Aerojet’s acquisition of  Pratt & Whitney Rocketdyne in 2012, Blue Origin president Rob Meyerson saw an opportunity to fill a gap in the defense industrial base. Blue Origin publicly entered the liquid rocket engine business by partnering with ULA on the development of the BE-4, and working with other companies. Meyerson announced the selection of Huntsville, AL as the location of Blue Origin’s rocket production factory in June 2017. Blue Origin began work on the BE-4 in 2011, although no public announcement was made until September 2014. This was their first engine to combust liquid oxygen and liquified natural gas propellants. In September  2014—in a choice labeled "a stunner" by SpaceNews—the large launch vehicle manufacturer and launch service provider United Launch Alliance selected the BE-4 as the main engine for a new primary launch vehicle. Blue Origin said the "BE-4 would be 'ready for flight' by 2017." By April 2015, two parallel development programs were under way. One program was testing full-scale versions of the BE-4 powerpack, which are the set of valves and turbopumps that provide the proper fuel/oxidizer mix to the injectors and combustion chamber. The second program was testing subscale versions of the engine's injectors . The company planned to begin full-scale engine testing in late 2016 and expected to complete development of the engine in 2017. By September 2015, Blue Origin had completed more than 100 development tests of several elements of the BE-4, including the preburner and a "regeneratively-cooled thrust chamber using multiple full-scale injector elements". The tests were used to confirm the theoretical model predictions of "injector performance, heat transfer, and combustion stability", and data collected was being used to refine the engine design. There was an explosion on the test stand during 2015 during powerpack testing. Blue Origin built  two larger and redundant test stands to follow, capable of testing the full thrust of the BE-4. In January 2016, Blue Origin announced that they intended to begin testing full engines of the BE-4 on ground test stands prior to the end of 2016. Following a factory tour in March 2016, journalist Eric Berger noted that a large part of "Blue Origin's factory has been given over to development of the Blue Engine-4". Initially, both first-stage and second-stage versions of the engine were planned. The second stage of the initial New Glenn design was to have shared  the same stage diameter as the first stage and use a single vacuum-optimized BE-4, the BE-4U. In the event, they backed away from this plan. The first engine was fully assembled in March 2017. Also in March, United Launch Alliance indicated that the economic risk of the Blue Origin engine selection option had been retired, but that the technical risk on the project would remain until a series of engine firing tests were completed later in 2017. A test anomaly occurred on 13 May 2017 and Blue Origin reported that they lost a set of powerpack hardware. In June  2017, Blue Origin announced that they would build a new facility in Huntsville, Alabama to manufacture the large BE-4 cryogenic rocket engine. The BE-4 was first test fired, at 50% thrust for 3 seconds, in October 2017. By March 2018, the BE-4 engine had been tested at 65% of design thrust for 114 seconds with a goal expressed in May to achieve 70% of design thrust in the next several months. By September 2018, multiple hundreds of seconds of engine testing had been completed, including one test of over 200 seconds duration. In October 2018, Blue Origin President Bob Smith  announced that the first launch of the New Glenn had been moved back to 2021, and in 2021 an additional slip to late 2022 was announced. This caused the first flight test of the BE-4 to be scheduled for the initial Vulcan Centaur launch rather than on New Glenn. By February 2019, the BE-4 had acquired a total of 1800 seconds of hot fire testing on ground test stands, but had yet to be tested above pounds of thrust, about 73 percent of the engine's rated thrust of . By August 2019, BE-4 was undergoing full power engine tests. In  July 2020, the first pathfinder BE-4 was delivered to United Launch Alliance for integration testing with Vulcan Centaur. In August 2020, ULA CEO Tory Bruno stated that the second test BE-4 would be delivered soon, followed quickly by the first flight-qualified ones. He noted an ongoing issue with the BE-4’s turbopumps. At the time, Blue Origin was still troubleshooting the 75,000-horsepower pumps that bring fuel to the BE-4’s main combustion chamber, Bruno said, adding that he was confident the issues would be resolved soon. In October, Bruno stated that the issue was resolved and that the  engine was moved into production; but it was not. By August 2021, it had become clear, even publicly, that the BE-4 engine program was in trouble. Delays had been accruing in the program for four years, including turbopump problems, combustion instability, overheating, and shorter-than-planned engine life. In addition, company management issues have left insufficient hardware to build development engines, leading to extended periods where no testing could be done, as well as issues related to company CEO Bob Smith and Jeff Bezos' distractions. Blue Origin has had difficulty getting the engines to run successfully at full power for  a full-duration burn. The company made the "risky decision" to ship the flight engines—currently not fully assembled—to their customer, ULA, before they had completed full qualification testing, meaning formal delivery may still occur in early 2022 rather than the earlier promised dates. According to long-time space reporter Eric Berger of Ars Technica, the relationship with ULA has deteriorated, in part because Blue tried to renegotiate for a higher price in 2017 than had been agreed to in 2014. Applications. By 2017, the BE-4 was being considered for use on two launch vehicles then under development. Prior  to this, a modified derivative of the BE-4 was also being considered for the experimental XS-1 spaceplane for a US military project, but was not selected. By 2018, it was the selected engine for both the Blue Origin New Glenn and the ULA Vulcan launch vehicles. Vulcan. In late 2014, Blue Origin signed an agreement with United Launch Alliance to co-develop the BE-4 engine and to commit to use the new engine on the Vulcan launch vehicle, a successor to the Atlas V, which would replace the Russian-made RD-180 engine. Vulcan will use two of the BE-4 engines  on each first stage. The engine development program began in 2011. The ULA partnership announcement came after months of uncertainty about the future of the Russian RD-180 engine that has been used in the ULA Atlas V rocket for over a decade. Geopolitical concerns had come about that created serious concerns about the reliability and consistency of the supply chain for the procurement of the Russian engine. Initially, ULA expected the first flight of the new launch vehicle no earlier than 2019 but by 2018, that target had moved out to 2021. Since early 2015, the BE-4 had been in  competition with the AR1 engine for the Atlas V RD-180 replacement program. While the BE-4 is a liquified natural gas engine, the AR1, like the RD-180, is kerosene-fueled. In February 2016, the US Air Force issued a contract that provides partial development funding of up to to ULA in order to support use of the Blue BE-4 engine on the ULA Vulcan launch vehicle. Initially, only was to be disbursed by the government with additional to be spent by a ULA subsidiary on Vulcan BE-4 development. Although was the original USAF contract amount to Aerojet Rocketdyne (AR) to advance  development of the AR1 engine as an alternative for powering the Vulcan rocket, by June 2018, the USAF had renegotiated the agreement with AR and decreased the Air Force contribution—5/6ths of the total cost—to . ARR put no additional private funds into the engine development effort after early 2018. Bezos noted in 2016 that the Vulcan launch vehicle is being designed around the BE-4 engine; ULA switching to the AR1 would require significant delays and money on the part of ULA. This point had also been made by ULA executives, who clarified that the BE-4 is likely to cost 40 % less than the AR1, as well as benefit from Bezos capacity to "make split-second investment decisions on behalf of BE-4, and has already demonstrated his determination to see it through. [whereas the] AR1, in contrast, depends mainly on U.S. government backing, meaning Aerojet Rocketdyne has many phone numbers to dial to win support". New Glenn. The engine is to be used on the Blue Origin large orbital launch vehicle New Glenn, a -diameter two-stage orbital launch vehicle with an optional third stage and a reusable first stage. The first flight and orbital test is planned for no earlier  than late 2022, although the company had earlier expected the BE-4 might be tested on a rocket flight as early as 2020. The first stage will be powered by seven BE-4 engines and will be reusable, landing vertically. The second stage of New Glenn will share the same diameter and use two BE-3 vacuum-optimized hydrolox engines. The second stage will be expendable. XS-1. Boeing secured a contract to design and build the DARPA XS-1 reusable spaceplane in 2014. The XS-1 was to accelerate to hypersonic speed at the edge of the Earth's atmosphere to enable its payload to  reach orbit. In 2015, it was believed a modified derivative of the BE-4 engine was to power the craft. In 2017, the contract award selected the RS-25-derived Aerojet Rocketdyne AR-22 engine instead. The XS-1 was cancelled in 2020. Availability and use. Blue Origin has indicated that they intend to make the engine commercially available, once development is complete, to companies beyond ULA, and also plans to utilize the engine in Blue Origin's own new orbital launch vehicle. As of March 2016, Orbital ATK was also evaluating Blue engines for its launch vehicles. The BE-4 uses liquified natural gas  rather than more commonly used rocket fuels such as kerosene. This approach allows for autogenous pressurization, which is the use of gasified propellant to pressurize liquid propellant. This is beneficial because it eliminates the need for pressurization systems that require the storage of a pressurizing gas, such as helium. Although all early BE-4 components and full engines to support the test program were built at Blue's headquarters location in Kent, Washington, production of the BE-4 will be in Huntsville, Alabama. Testing and support of the reusable BE-4s will occur at the company's orbital launch facility at Exploration Park  in Florida, where Blue Origin is investing more than in facilities and improvements. Technical specifications. The BE-4 is a staged-combustion engine, with a single oxygen-rich preburner, and a single turbine driving both the fuel and oxygen pumps. The cycle is similar to the kerosene-fueled RD-180 currently used on the Atlas V, although it uses only a single combustion chamber and nozzle. The BE-4 is designed for long life and high reliability, partially by aiming the engine to be a "medium-performing version of a high-performance architecture". Hydrostatic bearings are used in the turbopumps rather than the  more typical ball and roller bearings specifically to increase reliability and service life.