Bruno Le Maire, the former French finance minister, said in 2021 that the Ariane 6 was a “poor strategic choice.” More recently, in October last year, the head of ESA said the continent's space industry must “catch up” with international competitors like SpaceX and develop a reusable launch vehicle “relatively quickly.”
In his entry for ESA's BEST! initiative, ArianeGroup proposes to replace the solid-fuel side boosters of the Ariane 6 rocket with new liquid-fuel boosters. The boosters would be developed by MaiaSpace, a French subsidiary of ArianeGroup that is working on its own partially reusable small satellite launch vehicle. MaiaSpace and ArianeGroup would convert the methane-powered booster of the Maia rocket for use on the Ariane 6.
Isar Aerospace's concept for a reusable first stage booster (left) and ArianeGroup's proposal for an Ariane 6 rocket with reusable strap-on boosters (right).
Credit: ESA/Isar Aerospace/ArianeGroup
Isar Aerospace's concept for a reusable first stage booster (left) and ArianeGroup's proposal for an Ariane 6 rocket with reusable strap-on boosters (right).
Credit: ESA/Isar Aerospace/ArianeGroup
ArianeGroup's proposal was first reported by European Spaceflight, which said the concept presented to ESA is similar to an ArianeGroup proposal from 2022, when the company described the liquid, reusable boosters as a “plug-and-play” alternative to Ariane 6's solid-fueled boosters, reducing operating costs and increasing launch rates.
The details of ArianeGroup's latest proposal have not been published, but the concept was summarized in a paper presented at the 2025 European Conference on Aerospace Sciences.
Isar Aerospace, a German rocket startup, won a separate BEST! contract from ESA to study a demonstrator for a reusable first stage based on the company's Spectrum light rocket. The original design of the Spectrum rocket is expendable. The first test flight last year ended in failure, and Isar is preparing the 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 systems development plans and define plans and costs for a 'major flight demonstration'.
MaiaSpace's rocket won't launch until 2027 at the earliest, and a decision to use it as a basis for new Ariane 6 boosters is unlikely to pay off until long after Maia is flying on its own. Even if ESA and ArianeGroup were to go this route, the Ariane 6 rocket would still be largely expendable.
