Roth filament winder to facilitate major Ariane 6 weight/cost cuts

One of the world’s largest filament winding systems will soon begin manufacturing components for the Ariane 6 space launch vehicle, which is expected to transport satellites into Earth orbit for the European Space Agency (ESA) as early as 2020. Designed by Roth Composite Machinery (Steffenberg, Germany) in close cooperation with Roth’s customer, Avio (Colleferro, Italy), a leading manufacturer of space propulsion systems, the massive collection of Roth filament winding machinery will enable Avio to produce, among other components, the external casings for Ariane 6 booster rockets — the lift-off propulsion motors for the launch system.

The engine casings and many other components of launch vehicles, today, are built with lightweight composites. Because the casings are typically cylindrical, filament winding is commonly the process of choice, but prepreg processes also are used for some components. Filament wound carbon composite booster cases will, in the Ariane 6, replace the steel cases currently used in active-duty Ariane 5 vehicles. Composites use, in this case, will reduce the weight of Ariane 6 booster stages, compared to those of its predecessor, by as much as 35%. Their use at current levels also will have a marked impact on the Ariane 6 system’s overall cost of operation: The expenses per load-ton are expected to plummet by as much as 50%.

Avio and Roth reportedly have put to good use their common experience from former projects related to manufacturing Ariane 5 and Vega rockets. Accordingly, the new filament winding center has a maximum length of 17m, a large working diameter (3.6m), and is capable of supporting a winding mandrel that weighs approximately 120 MT. The system is equipped with three carriages that support three different winding processes; each carriage has a length of 7.4m and can move up to 90m per minute.

The first carriage is used for winding heat protection tape onto the mandrel in mold-less composite construction (first layer inside the booster). After the vulcanization of the tape, the towpreg winding process is effected by using the second carriage. The third carriage is equipped with a fiber delivery head for automated tape laying (ATL) — a feature for which Avio is seeking patent protection. This technology enables precise laydown of tape in complex geometrical shapes for the attachment parts of the boosters. Tapes are cut and trimmed by means of an ultrasonic cutting head. The ATL technology was developed by Avio together with Roth and another partner based in Italy.

Ariane 6 boosters are 15m long with a diameter of up to 3.6m. Depending on payload size and weight, two or four boosters per rocket, filled with solid fuel, will ensure sufficient boost for the first flight phase. Manfred Roth, president of the family-owned company, Roth Industries, to which Roth Composite Machinery belongs, says of the company’s latest move, “In the composites sector, we belong to the world market leaders.”