According to ArianeGroup, which is developing Prometheus under contact to ESA, testing will continue at the end of 2023 at the German aerospace agency DLR’s test site in Lampoldshausen, Germany. 

The 100-tonne thrust class Prometheus features extensive use of new materials and manufacturing techniques designed to reduce its cost to just a tenth of Ariane 5’s Vulcain 2, an upgraded version of which – Vulcain 2.1 – powers the core stage of Ariane 6. 

Prometheus burns liquid oxygen-liquid methane fuel. Methane is clean burning and simplifies handling, to help enable reusability and reduce the cost of ground operations before and after flight. A version using liquid hydrogen-liquid oxygen is also being developed. 

Prometheus features variable thrust and multiple ignition capability. Additive layer manufacturing – so-called 3D printing – features extensively, reducing the number of parts, speeding up production and reducing waste. 

For the Vernon and Lampoldshausen tests, Prometheus is mounted in a prototype of a reusable rocket stage, called Themis, which is being developed in parallel with the engine. Later, this engine-stage combination will attempt a series of “hop-tests”, lifting a few meters above the ground to check flight and landing capability. 

Together, Prometheus and Themis are envisioned to be common technological building blocks for a future family of European launchers.