Europe’s bid to slash the cost of access to space got another boost at Paris today in the form of a reusable rocket engine intended to cost just €1 million ($1.1 million) – compared to the €10 million cost of the disposable Vulcain 2 that powers the Ariane 5 heavy lifter.

The European Space Agency today signed a contract with Ariane prime contractor ArianeGroup to develop a demonstrator called Prometheus. The reusable liquid oxygen-methane engine concept is to undergo first testing in 2020 and is ultimately intended to power European launchers from 2030.

Meanwhile, says ArianeGroup chief executive Alain Charmeau, “all the stops” remain out in development of the Ariane 6, set to fly from 2020. Ariane 6 launches are to cost €70 million – less than half bill for Ariane 5, and on a par with the cost of a ride on SpaceX’s smaller Falcon 9. Ariane 6 features a modular design and developments of proven Ariane 5 technology, including an iteration of Vulcain 2. Its solid fuel boosters will also double as the first stage of the in-development Vega C light launcher.

Falcon 9 is not technically radical. But, by starting with a clean sheet design, purpose-built industrial infrastructure and several hundred million dollars of investment and launch contracts from NASA, SpaceX has created a streamlined business able to undersell rivals such as Ariane 5 and the Atlas V and Delta IV launchers from US leader United Launch Alliance. Those established launchers are highly reliable but costly; all use technology dating back to the 1980s and dispersed industrial infrastructures. ULA is a Lockheed Martin-Boeing joint venture born of Cold War-era organisational priorities; Ariane rockets come together via a cumbersome network of suppliers devised not for cost efficiency but by a European political reality which has historically dictated that contracts must be spread equitably between EU member states that contribute to a programme budget.

Europe’s response to SpaceX is not only the technically more efficient Ariane 6 modular launcher. Leaders in Brussels have made a clear statement of intent to retain an indigenous European capability to access space, and as such have stepped away from the notion of “juste retour” budget-spreading in favour of the consolidation of the Ariane programme. ArianeGroup is a joint venture between Airbus and Safran – the business is formally Airbus Safran Launchers until 1 July – and has recently taken control of launch operator Arianespace, which runs Europe’s space port in French Guiana.

Hence, Europe’s launch offering sits under one roof, from concept and design through to sales and operations. The Vega light launcher is provided by prime contractor ELV, owned by Avio and the Italian Space Agency. That arrangement had recently to pass scrutiny by the European competition authorities, who decided that Arianespace’s essentially in-house relationship to the Ariane 5 and 6, and also the Soyuz medium-weight lifter, would not disadvantage ELV or prospective customers of the much lighter Vega.

The European Commission and European Space Agency are essentially buying services from ArianeGroup – which, while contracted to develop launchers whose performance is dictated by the EC and ESA, must compete for their business. Critically, under this new order ArianeGroup relies on commercial business such as the orbiting of telecommunications satellites, and must be cost competitive to survive. The number of launches bought annually by European institutions – be they the EC or ESA, weather service EUMETSAT or national governments – is small compared with the large number of flights to space demanded by US counterparts. Their business most typically goes, for national security or political reasons, to ULA, SpaceX or Orbital ATK.

Separately, ArianeGroup is working on reusability concepts beyond Prometheus that may be worked into Ariane 6 iterations during the 2020s. While SpaceX is already returning completed main stages and engines to the ground via powered, soft landings, the European effort is focussed on recovering the engine, which makes up the bulk of the cost of a launcher. The Adeline (ADvanced Expendable Launcher with INnovative engine Economy) concept involves a detachable, winged engine housing that would fly back to a runway landing.

Adeline engine module returns c AIRBUS

Adeline engine module return to runway, artist's impression

Airbus Defence & Space

ULA’s competitive response has been to initiate development of its own modular concept, called Vulcan, to succeed Atlas V and Delta IV in the 2020s. Engine recovery is a key feature.

SpaceX boss Elon Musk insists that it will revolutionise space flight and the company has, earlier this year, succeeded in re-flying a partially recycled launcher. Some insight into the refurbishment process came from SpaceX vice president for commercial sales Jonathan Hofeller, speaking at space insurance conference in London in June. He told the World Space Risk Forum that where it took SpaceX nearly a year to refurbish the first booster for re-use, a second was readied in a couple months. Each part, he said, is refurbished, and if the booster as a whole is not as good as a new one it is retired. SpaceX, he says, sees "reliability as closely coupled with reusability".

Whether reusability becomes a significant factor in launch cost control remains to be seen.

NASA’s Space Shuttles were intended to fly over and over almost like an airliner, but in practice post-flight refurbishment was slow and costly; disposable launchers would have been far cheaper and design-for-reuse was certainly a major contributing factor in the total loss of two orbiters, killing 14 crew. Reusability costs an estimated 40% of Falcon 9’s payload capability to accommodate the fuel needed to fly back from the edge of space, as well as lift landing gear and the thermal protection needed to survive re-entry.

Today’s reusable launcher designs benefit, of course, from the Space Shuttle experience as well as three decades of subsequent technology development. But while it is clearly technically possible to reuse major launcher components, and experts generally anticipate some cost savings, Musk’s insistence that reusability will revolutionise space access costs is far from generally assumed.