Arianespace and ESA: Developing Low-Cost and Green Engine Technology

The European Space Agency (ESA) and the launch services company Arianespace are developing an ultra-low-cost reusable rocket engine. Their Prometheus will not only cost a tenth of the previous favorite Ariane 5’s Cilcain 2 engine but also use liquid oxygen-methane propellants that are more environmentally friendly. The first demonstrators for the new engine could take place before the end of the year.

Yisela Alvarez Trentini
4 min readNov 4, 2020

The ESA began funding Prometheus in June 2017 through an investment of €85 million ($91 million) for their Future Launchers Preparatory Programme. Earlier this year, the program received an official move ahead, after tests at the German Aerospace Center’s Lampoldshausen facility validated Prometheus’s hardware components.

The engine is, at the moment, a baseline for future developments. Its short term technology developments are expected to benefit existing engines such as the Ariane 6 and act as a precursor to several ultra-low-cost rocket propulsion systems that could fit a fleet of new launch vehicles.

Prometheus promises to be a cheaper alternative to existing launchers and a highly flexible engine that combines high efficiency and operational simplicity with a more widely available and easier to handle methane propellant. The project, part of ESA’s Future Launchers Preparatory Programme, is set to eventually become the main European propulsion technology.


Arianespace is a leading global launch services company that serves international clients from its headquarters in France, the United States, Japan, and Singapore. Created in 1980, Arianespace has about 220 employees and an assigned mission of guaranteeing independent access to space for the whole of Europe.

The company offers three launch solutions. The Ariane 5 is a heavy-lift launcher with 109 successful launches and over 225 satellites orbited; it is also the global benchmark for launches to geostationary transfer orbit (GTO). The Soyuz is a medium-lift launcher that is versatile and especially well-suited to deploying satellite constellations. Since 2011, Soyuz has completed over 50 missions. Finally, the Vega is a lightweight launcher ideally suited for Sun-synchronous Earth observation satellites and has completed 16 launches.

Arianespace’s services are operated from South America (French Guiana Spaceport) and Central Asia (Baikonur Cosmodrome). The company’s 2019 revenue is estimated at around €1 billion ($1.17 billion) and has a current order book value of €3.5 billion ($4 billion).


The ESA is an intergovernmental organization dedicated to the exploration of space. The agency’s programs include human spaceflight, uncrewed operations to other planets and the moon, and science and telecommunications, among others.

The agency was founded in 1975 and includes 22 European states. With headquarters in Paris, the principal components of the organization are distributed across the continent. Their Research and Technology Centre is in the Netherlands, their Operations Centre and Astronaut Center in Germany, and their Astronomy Center in Spain. The ESA has cooperated with NASA on many projects and developed several independent probes and spacecraft such as Giotto (which examined the core of Halley’s comet in 1986), Ulysses (launched in 1990 to explore the Sun’s polar regions), and a system of meteorological satellites known as Meteosat.

One of ESA’s focus is to use space for green growth. This is done by providing alternative infrastructure monitoring, supplying climatological data, enabling remote communication, and empower forecasting through artificial intelligence (AI), blockchain, the internet of things (IoT), augmented/virtual reality (AR/VR), and uncrewed aerial vehicles.

Awaiting Prometheus with Ariane 6

With a cost of one-tenth of Ariane 5’s first stage, the reusable engine is on track for completion by the end of 2020, when we should expect to see a first ground test. Prometheus will leverage extensive 3D printing with the goal of reaching a cost of only €1 million ($1.17 million).

We could see the new engine ascend to the skies in the 2030s, although by then, a lot of its technology will have already been applied to the Ariane 6’s expendable Vulcain 2.1 first-stage engines and Vinci second-stage engines. Spinoff electrical valves and 3D-printed parts could also reduce the cost of Ariane 6’s expendable engines.

Although we might have to wait a little longer to see Arianespace and ESA implement fully reusable launchers, there’s a lot to look forward to with the latest Ariane 6. ArianeGroup is currently seeking funding for five main improvements. The first is an enhanced payload adapter to support more rideshares. There’s also an auxiliary power unit (APU) that can deliver satellites directly into circularized geosynchronous orbit (instead of a typical elliptical transfer orbit), a carbon composite upper stage that will make Arian lighter, and a possible simplification of the dual solid rockets to improve manufacturing processes.

Last May, ArianeWorks announced that a young rapid-prototyping French firm called MyCTO was building the first prototype of the Themis, a demonstrator that will examine how to recover the first stage of a rocket. Themis will use a reusable and environmentally-friendly Prometheus engine for its much-anticipated landing.

This article was originally published in Startup Savant on October 31, 2020. Link:



Yisela Alvarez Trentini

Anthropologist & User Experience Designer. I write about science and technology. Robot whisperer. VR enthusiast. Gamer. @yisela_at