The French space agency CNES has issued a call for proposals to develop a reusable upper stage for a heavy-lift rocket.
On 3 February, CNES published an initial overview of Project DEMESURE (DEMonstration Étage SUpérieur REutilisable / Reusable Upper Stage Demonstration), describing it as one of the agency’s nine Priority Innovation Vectors for space transportation. In an initial introduction, it states that the development of a reusable upper stage “could offer competitive advantages at a time of growing launch capacity demand.”
With Project DEMESURE, CNES aims to demonstrate the recovery and reuse of a launch vehicle upper stage. The agency explained that the ultimate goal is to develop a reusable upper stage for a two-stage rocket that can deliver 20 tonnes to low Earth orbit, a similar payload capacity to Ariane 6. The initial demonstration will, however, be conducted at a “reduced scale” with an incremental approach to the system’s development.
The call published on 3 February will cover development phases 0 and A. This includes the completion of a key system concept review, Phase 0 and Phase A technical requirements evaluation, cost estimation review, and a feasibility meeting. The deadline to submit proposals for this initial call is 26 February 2025.
A future call will deal with phases B through D, which will include the definition and fabrication of the demonstrator. Phase E will be the demonstration flight itself and will include the recovery and reuse of the upper stage demonstrator.
While this is currently a CNES-led project, it appears to be a natural successor to the Themis programme, which also originated within the French space agency. A future vehicle incorporating insights from Themis and DEMESURE could pave the way for a fully reusable European successor to Ariane 6.
