France’s Prometheus reusable engine becomes ESA project, gets funding boost

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WASHINGTON — A French reusable rocket engine program is getting a boost from the European Space Agency, which is ready to sign a contract with Airbus Safran Launchers that would lead to an engine test three years from now.

A small team of engineers from Airbus Safran Launchers and the French space agency CNES have poured a few million euros since 2015 into a liquid oxygen and-methane-fueled reusable engine dubbed Prometheus. ESA leaders agreed during December’s ministerial conference in Lucerne, Switzerland, to make Prometheus part of the agency’s Future Launchers Preparatory Program, or FLPP.

In an interview with SpaceNews, Airbus Safran Launchers CEO Alain Charmeau said FLPP is allocating 85 million euros ($91 million) to Prometheus to fund research and development leading to a 2020 test firing. Now that Prometheus is an ESA program, Charmeau expects more countries will get involved.

“ESA will pay the contract to Airbus Safran Launchers and then Airbus Safran Launchers will cooperate with European industry, of course France and Germany, but we will have also contributions from Italy, Belgium, Sweden and probably a couple of others to a smaller extent,” Charmeau said.

Europe has been reticent to jump into reusability. Both of its next-generation launchers — Ariane 6 and Vega C  — will be expendable. Airbus Safran Launchers, ESA’s prime contractor for the Ariane 6, has said the European market does not ensure enough launches to make reusability a profitable pursuit. Charmeau said the Prometheus work ESA has agreed to fund will evaluate the feasibility of developing a reusable engine with drastically lower cost.

Prometheus Engine
Digital rendering of Europe’s proposed reusable rocket engine, Prometheus. Credit: Airbus Safran Launchers

“If we have this answer by 2020, then we can work on the evolution of launchers either for reusability or not depending on the size of the market,” he said.

The target price for a Prometheus engine is 1 million euros, one-tenth the cost of the Ariane 6’s liquid-oxygen and liquid-hydrogen Vulcain 2.1 engine. The Prometheus program is making extensive use of new technologies and production methods, including 3-D printing, and a large amount of technical design work already completed in France and Germany, according to an Airbus Safran Launchers presentation.

Charmeau said the market dynamics that have dissuaded the company from reusability in the past are still the same, but the company wants to lay the foundation for long-term launcher development.

“We are preparing the market for 2030. Today we do not have in Europe an engine which has the capability to be reused for the main stage of the launcher. Until we have this engine, it is very difficult to design what could be a new launcher,” he said.

During December’s ministerial, ESA members committed 206.8 million euros to FLPP. Startup PLD Space of Spain, another member of the FLPP program, received 750,000 euros from ESA in November to study liquid-propulsion stage recovery for a small satellite launcher.

Airbus Defence and Space’s reusable first-stage engine concept, the Advanced Expendable Launcher with Innovative engine Economy, or Adeline, is a separate project from Prometheus, Charmeau said, but could combined with the liquid-propulsion system. Adeline proposes returning an Ariane first-stage engine by flying it back with deployable wings and landing on a runway.

“Prometheus might fit very well with this kind of reusable launcher concept,” Charmeau said.

European demand for Ariane 6

Airbus Safran Launchers is also trying to get a guarantee of demand for Ariane 6 launches from European government institutions ahead of its first launch. The company estimates that European government demand for launches accounts for only 27 percent of Arianespace’s launch activity, with the rest coming from the commercial sector. The U.S. market is 65-percent government demand, going largely to domestic launch providers, and the Russian market is 76-percent government, according to Airbus Safran Launchers numbers.

“The target now is to try to federate the European Commission, ESA, Eumetsat and national agencies for similar applications so that we organize a production order to be awarded to Arianespace as quickly as possible in order to give European industry a minimum critical mass for production of Ariane 6, and the same for Vega C,” Charmeau explained.

He said Airbus Safran Launchers is seeking a commitment of five Ariane 6 launches per year, and believes a commitment of two Vega C launches a year for Italy’s Avio would constitute enough demand to provide stability. Charmeau said demand for launches of European satellites is rising and should make this an attainable target.

“We anticipate a slight increase in institutional requirements in line with the increasing space budget in Europe, both at the European Commission level and ESA level, which means that there will be more programs, more satellites and therefore more launch services,” he said.

Charmeau said Airbus Safran Launchers wants to see a European representative, such as the European Commission or ESA, aggregate institutional demand and direct that to Arianespace. Such an organizational method is not in place today, and it is unclear how that might form. Charmeau said Airbus Safran Launchers will also be negotiating whether a guaranteed number of launches per year would replace the subsidy Arianespace gets to provide Europe with assured access to space.