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 for use on the Themis reusable rocket demonstrator, Ariane Next, the successor to Ariane 6, possibly a version of Ariane 6 itself, and the Maia reusable launch vehicle. 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. 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 Vulcain 2, Ariane 5's first-stage engine. By 2020, the program was funded and is under development by ArianeGroup. By 2025, the engine had completed two successful test firing campaigns including four successive ignitions in a single day.