The arrival of the American SpaceX forced the Europeans to start building Ariane 6. The development of the new launcher led to a complete reorganization of the industrial scheme.
A stone’s throw from the gigantic hall dedicated to the Ariane 5 – which surpasses the Arc de Triomphe in Paris -, the new building on the ArianeGroup site in Les Mureaux, in the Yvelines, seems quite modest. It is however in this construction completed less than two years ago that the main stage of the new European Ariane 6 launchers is assembled.
The reason for this reduction in size? The new rocket, which should fly in the second half of 2021, is manufactured horizontally rather than vertically to create flows similar to those of an automotive or aeronautical assembly line. “We have adopted the same working principles as in the other major industrial sectors, as Airbus does for example with the A350. This makes it possible to increase production rates, reduce waste and bring more reliability. There are also fewer anomalies, “explains Patrick Bonguet, director of the Ariane 6 program at ArianeGroup. Another advantage, simpler: the building is cheaper to maintain and heat.
A geographic distribution
The entire production chain has been rationalized across the group. For Ariane 5, each country brought its brick. The organization is now based on a more detailed geographical distribution of tasks, with, for example, the production of metal structures in Germany and composites in Spain. The German industrialist MTA thus produces all the ferrules (the external structures), which allows it to rotate its equipment more and therefore to produce cheaper. The Belgian Sabca, who just signed this week the first industrialization contract with ArianeGroup, has the exclusivity of actuation systems, which allow to orient the rocket.
This overhaul of the industrial scheme is one of the elements implemented by ArianeGroup and its European partners to make Ariane 6 less expensive to manufacture by 40% compared to its predecessor. Because if Ariane 5, originally designed to carry the European shuttle Hermès (which never saw the light of day), is the most reliable launcher in the world, it is too expensive and is no longer competitive compared to SpaceX, which has revolutionized the space launch market.
Improving competitiveness is also based on the use of new manufacturing technologies. A good example: the insulation of central tanks carrying liquid hydrogen and oxygen from Ariane 5, which is done by bonding … manual, plate by plate! An operation now replaced on Ariane 6 by a significantly faster and more efficient injection process.
A first for space Europe
The conventional welding techniques for aluminum sheets have been eliminated by friction stir mixing, which weakens structures less. It is a technology which consists in locally heating the area on which the welding is done, to cause a mixture of material. “It is the first time that this technique, already used elsewhere, has been applied in the space sector in Europe“, says Patrick Bonguet. This kind of new process nevertheless entails certain constraints: the concrete slab supporting the assemblies could not accept a deformation on the ground greater than 50 microns over 40 meters.
Another innovation in the new building: a special adjoining room has been created for tank pressure testing. Protected by an armored door, this room would see its outer wall detach in the event of an accidental explosion, to avoid destruction of the hall. For Ariane 5, these tests must take place in a gigantic underground well.
The overhaul of the processes is also valid for the assembly of the new Vulcain engine in Vernon, a huge wooded site three quarters of an hour from Les Mureaux. Additive manufacturing, very well suited to space products, has entered these engines. 3D printing makes it possible to reproduce very quickly complex parts that require hundreds of hours of conventional work, but also to produce elements that are impossible to shape otherwise. For Ariane 6, around ten references have already been qualified, including certain gas generators on the engine or an auxiliary power system for the upper stage.
Additive manufacturing, very well suited to space products, has entered.
ArianeGroup partners have also been asked to modernize their manufacturing processes, the only possible option for offering cheaper parts. “The requested cost reduction has sometimes been 30%,” admits a Belgian industrialist. “But this was done in good understanding with the client, from the designAnother compensation: the series will be larger, since Ariane 6 should lead to higher firing rates. Ina Maller, CEO of Thales Alenia Space Belgium, the company which manufactures many electronic equipment for the new launcher, explained that his company had made innovations in the manufacturing chain, “like using the augmented reality and of new data storage methods “.
The next step
Finally, thecontrol of Ariane 6 costs was also achieved by increasing the use of existing components, like microprocessors used in other sectors or inertial units derived from airliners. Overall, with a few exceptions, it is also the entire launcher that uses proven technologies. But ArianeGroup is already preparing the next steps: one of its teams is engaged in development, on the Vernon site, of the new Prometheus engine which is expected to cut production costs by 10 compared to current Vulcain 2 engines. This engine, which will make massive use of 3D printing and will use methane and oxygen, will be reusable. Its complement is also already being studied: the Themis demonstrator, intended to demonstrate the feasibility of a recoverable first stage concept.