ESA backs flight demonstrations of reusable rocket boosters

The European Space Agency announced plans to support industry-led flight demonstrations of reusable first stages and boosters, under a new phase of the initiative to strengthen European space transport known as BEST!.

On 27 October the agency published a call under BEST!2 for demonstration proposals aimed at accelerating the development of reusable first-stage or booster technologies and proving them in actual flights. According to the call text, the activities will support system-level proposals for recovering and re-flying the first stage, with the aim of reducing technical and operational risk and speeding the entry of these technologies into operational launch systems.

The call currently appears on the agency's tendering platform with an intended status, a status that usually means the detailed tender documents setting budgets and dates have not yet been issued. The call follows the first round of the initiative, in which contracts were awarded in late 2024 to ArianeGroup and Isar Aerospace and covered stages from preliminary studies to preliminary design and estimation of the cost of future flight demonstrations.

ArianeGroup proposed converting the first stage of the small launch vehicle being developed by its subsidiary MaiaSpace into reusable liquid boosters for a future version of Ariane 6, while Isar proposed developing a demonstrator for a reusable first stage for the Spectrum rocket. It is not yet clear whether the new call will provide further funding for either project or open the door to other proposals. The agency also published a separate procurement notice for the BEST! Reloaded initiative to fund a new round of preliminary studies for medium and heavy launch vehicles in Europe, and both activities fall under the Future Launchers Preparatory Programme.

What do these terms mean?

Reusable booster: Part of a rocket that returns to Earth after launch to be used again, reducing the cost of each flight.

First stage: The lower part of a rocket that operates at liftoff and carries most of the fuel, and separates after its fuel is consumed.

BEST!2: A phase of a European initiative that supports proving reuse technologies in actual flights instead of limiting itself to studies.

Future Launchers Preparatory Programme: A programme of the European Space Agency that funds technologies for Europe's upcoming launch systems.