Prometheus is a backronym from the original French project designation PROMETHEE, standing for "Precursor Reusable Oxygen Methane cost Effective propulsion System", and for the Titan Prometheus, from Greek mythology, creator of humanity, and god of fire, known for giving fire to humanity in defiance of the gods.
By 2020, the program was funded and is under development by ArianeGroup.[3]
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.[4][3]
General characteristics
The engine is planned to have the following features:
Methane–oxygen propellant.
Extensive use of metal 3D printing (up to 50% of the engine).[3]
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.[4]
By June 2020, the ESA was on board 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 5Vulcain 2 engine".[3]
In 2021, ESA invested an additional €135 million in the project,[7] including €30 million from DLR.[8]
A Prometheus engine was started up in Nov 2022.
The engine had a successful 12 second test firing in June 2023, at the THEMIS test stand in Vernon, France.[9]
An additional successful hot fire test was reported at the end of 2024.[10]
