EU-made carbon fibres and prepreg materials for future spacecraft An EU-funded project developed carbon fibres in the high-modulus range targeting satellite components and intermediate-modulus carbon fibres targeting launcher vehicles. Industrial Technologies Space © Vadim Sadovski/Shutterstock.com Composite structures for space applications should be light yet strong. They should also resist damage while also handling significant temperature variations. In this context, high-modulus carbon fibres and the related fibre-reinforced polymer composites are critical materials for future spacecraft. “Composites have hitherto been provided mainly by non-European companies. There is a need for a manufacturing site in Europe to guarantee non-dependence on this technology. As these materials are used in military applications, their purchase from Japanese and US suppliers is not necessarily a straightforward process,” explains Nuno Rocha, coordinator of the EU-funded SpaceCarbon project. “Given the strategic importance of the space industry, especially of satellites, security of supply is important to guarantee continuity of Space programmes.” Keeping Europe in the lead in composite manufacturing This observation shaped the remit of the EUCARBON project. The first European production line for a precursor material (a polymer-based fibre serving as a raw material for carbon-fibre production) was installed at the FISIPE site near Lisbon in Portugal. The production capacity meets the expected demand for high-modulus carbon fibres in satellite subcomponents. These first produced carbon fibres achieved tensile modulus of 348 GPa and tensile strength of 4 200 MPa. This was the highest modulus carbon fibre produced in Europe until that moment and was an important step to establish the capacity to develop and produce carbon fibres in the high-modulus range. Building on EUCARBON’s success, SpaceCarbon further enhanced the carbon-fibre properties and the manufacturing process to make products competitive compared to those from non-European sources. SpaceCarbon also expanded the pilot facility capacity to produce intermediate-modulus fibres for launcher structures. Intermediate- and high-modulus carbon fibre demonstrators “We developed two satellite components using high-modulus carbon fibres: a full-scale sandwich reflector and a structural tube. The targeted carbon-fibre tensile strength ranged from 4 000 to 5 000 MPa, while the tensile modulus from 380 to 400 GPa,” notes Rocha. The first component demonstrator for the launcher was a reduced-scale vessel manufactured with a pre-impregnated tow semi-product. The second demonstrator – a skirt (structural component connecting the motor case to the launcher) – was produced with towpreg and unidirectional tape semi-products. Trials included manufacturing 50 k, 24 k and 12 K filament fibres. The tensile strength of the produced carbon fibres ranged between 5 000 and 6 000 MPa, while the tensile modulus ranged between 280 and 320 GPa. Promising prepreg formulations Project activities also revolved around developing enhanced prepreg formulations for future spacecraft structural composites. Prepregs were developed using reference and European fibres produced by a project partner. Two prepreg processes were implemented: impregnation by resin dip, where no solvents were used; and hot melt impregnation, where solid resin was heated to impregnate the fibres. Special focus was placed on testing the resin outgassing (a critical requirement for satellite applications). SpaceCarbon implemented material hybridisation strategies to improve the toughness and conductive properties of the prepreg materials and reduce production costs. Furthermore, hybrid composites were developed and manufactured by partially replacing high-modulus fibre prepregs with lower-modulus and lower-cost ones, while meeting performance requirements. “The newly developed materials are competitively positioned in the fibre and composites market for space applications. The fact that they are produced in Europe guarantees greater availability and shorter delivery times,” Rocha concludes. Keywords SpaceCarbon, carbon fibres, prepreg, composites, satellite, launcher, spacecraft, Europe, strength, modulus
