ESA considers righting the wrongs of Ariane 6 by turning it into a Franken-rocket

Former French Finance Minister Bruno Le Maire said in 2021 that Ariane 6 was a “poor strategic choice”. As recently as October last year, the head of ESA said the continent’s space industry should “catch up” with international competitors like SpaceX and develop reusable launchers “relatively rapidly”.

Presenting the best of ESA! initiative, ArianeGroup has proposed replacing the solid-fueled side boosters of the Ariane 6 rocket with new liquid-fueled boosters. The booster will be developed by Arianegroup’s French subsidiary Miaspace, which is working on its own partially reusable small satellite launcher. MaiaSpace and ArianeGroup will convert the Maia rocket’s methane-fueled booster for use on Ariane 6.

ArianeGroup’s proposal was first reported by European Spaceflight, which said the concept presented to ESA is similar to a 2022 ArianeGroup proposal, when the company described liquid reusable boosters as a “plug-and-play” alternative to Ariane 6’s solid-fueled boosters, helping to reduce operating costs and increase launch rates.

Details of ArianeGroup’s latest proposal have not been published, but the concept was summarized in a paper presented at the European Conference on Aeronautics and Astronautics in 2025.

German rocket startup, Isar Aerospace, wins a separate Best Award! Contract from ESA to study a demonstrator for a reusable first stage based on the company’s Light-class Spectrum rocket. The initial design of the Spectrum rocket is expendable. Its first test flight last year ended in failure, and Isar is preparing a second Spectrum rocket for another launch attempt later this month.

ESA asked ArianeGroup and Isar Aerospace to assess the feasibility of their proposals, develop technology and system development plans, and define plans and costs for a “key flight demonstration”.

MaiaSpace’s rocket won’t launch until 2027 at the earliest, and any decision to use it as the basis for a new Ariane 6 booster isn’t possible until Maia can fly on its own. Even if ESA and ArianeGroup take this route, the Ariane 6 rocket will still be primarily expendable.