About Horizon Europe
project SALTO

Esrange Space Center

The Horizon Europe project SALTO is coordinated by ArianeGroup and will be implemented by 25 consortium partners and 1 affiliated partner. Each partner has complimentary competencies and expertise. The target vehicle, which comprises various technologies matured by ArianeGroup and its partners, will pave the way for even more ambitious demonstrations to reproduce the high-energy trajectory representative of an actual operational launch.

SALTO: Advancing European Space Access, Autonomy, & Competitiveness

Prometheus® rocket
engine & Themis demonstrator

Prometheus® rocket engine

The next-generation Prometheus® rocket engine is a liquid methane-liquid oxygen engine currently under development by the European Space Agency (ESA) in collaboration with the French national space agency (CNES) with support from the German aerospace agency (DLR) for use in future launch vehicles. The engine is designed to be highly efficient and cost-effective, using liquid oxygen (LOx) and methane as fuel sources instead of traditional rocket fuels such as hydrogen. It is designed to be highly reusable, with a long lifespan and minimal maintenance requirements. The engine is expected to play a key role in future missions, including launching commercial satellites.

Themis demonstrator

Themis is a European Space Agency (ESA) programme, led by ArianeGroup with the participation of Germany, France, Switzerland, Belgium, Sweden, Spain, Netherlands, Poland and Hungary (CMIN22 outcome). Themis demonstrator is 30 meters high for 3.5 meters in diameter and carries more than 130 tonnes of propellant.

Themis powered by the Prometheus® rocket engine

The Hop tests within the scope of the SALTO project will be conducted with 1 Prometheus® rocket engine. In the future, at the next stage of the reusable rocket development, the tests will also be undertaken with 3 Prometheus® rocket engines. These developments are the key technological building blocks for the next generation of reusable European launchers that aim to significantly reduce space launch costs compared to the current European rocket fleet.

SALTO project will culminate in flight test campaigns to demonstrate and validate the technologies necessary for a reusable launch vehicle.

Test campaign & its results

During the vertical hop tests, the launcher will be lifted up to 30 – 250 meters high using Prometheus® reusable engine demonstrator. The campaigns will involve operational teams for both the test site and the launch vehicle for launching and recovering the rocket stage. Once the rocket stage is recovered and back in safe mode, test data will be retrieved and shared across the SALTO team, allowing us to assess test results, elaborate the test report, and support maturation activities.

Themis reusable rocket roadmap

Hop Test Campaign

The SALTO project and the foreseen tests are complementary and coherent with ESA’s Themis reusable stage programme. Two test campaigns of the Themis reusable launcher stage prototype will be conducted in Kiruna, Sweden. After years of preparation and construction, the mainland EU’s first orbital launch complex, Spaceport Esrange, was officially inaugurated on January 13, 2023.

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The impact

The achievements and results of the SALTO project will contribute to the overarching objective of launch cost reduction by 50%, increasing launch service flexibility and reducing the environmental footprint.

Beyond the overarching reusability impact, several SALTO technologies will contribute to cost reduction:

Impact on SALTO consortium partners

All the consortium partners will benefit from participation in the project in terms of experience and expertise in their field of interest and business. After the project, they will be able to use the project results according to the IP management plan to design new solutions, products and technologies, conduct further research or provide new services. This project will also positively impact partner reputation, especially for start-ups and SMEs.