Reducing Space Costs: CNES’s DEMESURE Project Explores Upper Stage Reusability

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Project DEMESURE, or “DEMonstration Étage SUpérieur REutilisable,” is an ambitious initiative by the French National Centre for Space Studies (CNES) that aims to develop a reusable upper stage for a heavy-lift rocket, akin to the payload capacity of the Ariane 6. The project seeks to push the boundaries of rocket technology by making the typically expendable upper stage recoverable and reusable, thereby reducing the cost and environmental impact of space missions.

This project is an extension of the work initiated with the THEMIS program, where CNES, in collaboration with ArianeGroup, has been working on developing a reusable first-stage rocket. THEMIS, which stands for “Thématiques pour une Étude de Moteur Innovant et Systèmes,” is focused on creating a first-stage prototype that can be recovered and reused, much like SpaceX’s Falcon 9. THEMIS has been a stepping stone, providing valuable insights into reusable rocket technology, with tests including tank filling, engine ignition, and low-altitude “hop tests” to validate the concept of recovery and reuse.

The relationship between DEMESURE and THEMIS is one of progression. While THEMIS concentrated on the first stage, DEMESURE takes the learnings from THEMIS to tackle the complexities of a reusable upper stage. The THEMIS program has demonstrated the feasibility of reusable rocket components, and DEMESURE aims to apply this knowledge to a different, more challenging part of the rocket. The success of THEMIS in developing the Prometheus engine and testing various recovery technologies directly informs the strategies and methodologies of DEMESURE.

Both projects are part of a broader European endeavor to catch up with and potentially lead in the reusable launch vehicle sector. They share common goals of cost reduction, environmental sustainability, and increasing the frequency and flexibility of space missions. DEMESURE leverages the technological advancements and experimental data from THEMIS to address the unique challenges associated with recovering an upper stage, such as dealing with the intense heat of re-entry from higher altitudes and managing the delicate balance of fuel for re-ignition and landing.

As of early 2025, DEMESURE is in its developmental phase, with CNES outlining its objectives and methodologies.

The outcomes of both THEMIS and DEMESURE are eagerly awaited, as they could redefine the landscape of space travel, making it more accessible and sustainable. However, the path involves overcoming significant technical challenges, where the legacy of THEMIS might prove invaluable for the success of DEMESURE.

Last update on 2025-12-20 / Affiliate links / Images from Amazon Product Advertising API