Prometheus (rocket engine)


The Prometheus rocket engine is an ongoing European Space Agency (ESA) development effort begun in 2017 to create a reusable methane-fueled rocket engine potentially for subsequent technology use in the Ariane 6 or its successor rocket.[1]By 2020, the development program was fully funded, and is being developed for the ESA by Ariane Group.[2]

The engine is aimed to be reusable with substantially lower costs than traditional engines manufactured in Europe. The cost goal is to manufacture the Prometheus engine at one-tenth the cost of the Ariane 5's first-stage engine.[3][2]

This engine is to cost no more than 1 million euros.[citation needed]

  • Some parts will be made by 3d printing.[2]
  • It will use the Gas-generator cycle.[4]
  • It will have a thrust of 100 tons.[citation needed]
  • Combustion chamber pressure will be approximately 100 bar (10,000 kPa).[5][full citation needed]
  • The engine is being designed to be reusable 3 to 5 times.[citation needed]


The European Space Agency (ESA) began funding Prometheus engine development in June 2017 with €85 million provided through an ESA capital mechanism called the Future Launchers Preparatory Program.[1]

By June 2017, Patrick Bonguet, lead of the Ariane 6 launch vehicle program at ArianeSpace, indicated that it was possible the Prometheus engine could find a use on a future version of the expendable Ariane 6 launcher. In this scenario, a "streamlined version of Vulcain rocket engine called Vulcain 2.1 would have the same performance as Vulcain 2. The expendable Ariane 6 was then expected to make an initial launch in 2020.[3]

By June 2020, the ESA was onboard with this plan, and had agreed to completely fund the development of the Prometheus precursor engine to bring the "engine design to a technical maturity suitable for industry." The objective of the overall program as stated in June 2020 was to utilize Prometheus technology to eventually "lower the cost of production by a factor of ten of the current main stage Ariane 5 Vulcain 2 engine."[2]


  1. ^ a b Henry, Caleb (5 October 2017). "France's Prometheus reusable engine becomes ESA project, gets funding boost". SpaceNews. Retrieved 9 January 2018.
  2. ^ a b c d "ESA moves ahead on low-cost reusable rocket engine". ESA. 4 June 2020. Retrieved 4 June 2020.
  3. ^ a b Henry, Caleb (8 January 2018). "France, Germany studying reusability with a subscale flyback booster". SpaceNews. Retrieved 9 January 2018.
  4. ^ Iannetti, A.; Girard, N.; Tchou-kien, D.; Bonhomme, C.; Ravier, N; Edeline, E. (July 2017). PROMETHEUS, A LOX/LCH4 REUSABLE ROCKET ENGINE (PDF). 7th European Conference for Aeronautics and Space Sciences. doi:10.13009/EUCASS2017-537. Retrieved 2 March 2019.
  5. ^