Europe's Reusable Rocket Prepares for First Flight

September 29, 2025

The first model of the European Space Agency’s (ESA) reusable rocket demonstrator Themis is standing at its launch pad in Kiruna, Sweden.

The first model of ESA’s reusable rocket demonstrator Themis is standing on its own legs at its launch pad in Kiruna, Sweden.

Themis is investigating technologies to demonstrate rocket stage recovery and reuse. The first vehicle model – called T1H for Themis-1 engine-Hop – arrived at the Esrange Space Center over the summer, with its landing legs shipped separately. The legs are now installed, and T1H is standing tall.

Themis is set to be the first European demonstration of a full-scale vertical take-off and landing rocket element that uses cryogenic propulsion.

T1H is 30 meters tall standing on its legs and 3.5 meters wide, holding the necessary technologies for the low-altitude take-off and landing tests it is set to perform. Themis uses the Prometheus engine, almost as powerful as the Ariane 6 rocket’s main engine – but Prometheus can restart in flight and throttle its thrust to ensure a soft and safe landing.

Themis was transported by truck over 3,000 km from the ArianeGroup integration building in Les Mureaux, France, to the Swedish Space Corporation’s Esrange Space Center in the north of Sweden.

Preparing Themis T1H to move to the launch pad.

After final check at a Kiruna assembly building, Themis was moved to the pad in August and hoisted onto a tool to allow the swift assembly of its four legs. This is the first time the rocket stage demonstrator has had its four legs installed, now the demonstrator is fully assembled and ready for its wet dress-rehearsal preparing for a first flight.

Themis, the first European reusable main stage’s full-scale demonstrator, was developed by ESA’s future Space Transportation preparation programme, with ArianeGroup as prime contractor and multiple European industrial partners. Themis’s first flight campaign with T1H, will be realized in the scope of Horizon Europe project Salto, funded by the European Union. The Salto project is responding to the EU Space Research and Innovation Programme and is implemented by 25 consortium partners from 12 European Union countries.

ESA expects the first flight of Themis to occur in early 2026.

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