Themis (rocket)

Themis is a European demonstrator for a reusable first rocket stage, developed with ArianeGroup as prime contractor through the ArianeWorks innovation platform launched by ArianeGroup and the French space agency CNES, with funding from the European Space Agency. It is a stage of stainless steel tanks, about 28 to 30 metres tall and 3.5 metres wide depending on the version, fed by one to three methane-fuelled Prometheus engines that can be restarted in flight. It exists to prove the techniques Europe needs to launch, land vertically and fly again, as a step between Ariane 6 and a possible reusable successor, and it feeds the design of the MaiaSpace Maia rocket. The ground test prototype is called T1G, the first flying prototype T1H is built for low hops at Esrange in Sweden, and a three-engine version, T3, is meant for high flights from Kourou. No orbital flight is planned for the demonstrator itself.