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Space: how this sector promotes the development of composite materials and structures (also at INEGI!)

20 November 2020
Article by Nuno Rocha, coordinating researcher for activities in the Space sector, and Nuno Correia, responsible for the composite materials area at INEGI.

Space exploration has been one of the most powerful engines of technological development since it emerged. The technical challenges it imposes, from access to space to operating in a space environment, require new technical knowledge, and innovation in initiatives in the field of future and emerging technologies carried out on a large scale ("Big Sience").

In view of the emergence of these challenges, INEGI has stood out through its continued activity in this sector, largely developed within the scope of projects with the European Space Agency (ESA), covering various technological areas, such as the development of materials, manufacturing processes, design of structures, and testing and evaluation of systems for Space.

High-performance materials contribute to the economic viability of space missions

Reducing the weight of the structures and systems launched into space is one of these challenges, especially important since each launched kilogram can cost € 20,0001.

It is precisely as an answer to this challenge that the development of composite materials, or polymers reinforced with carbon fiber (CFRP), comes to be, as these can be five times more resistant and more rigid than the materials they replace2. Composite materials thus become economical enablers of access to Space. In addition to the high specific mechanical performance, these materials also provide space structures and systems with high thermal stability3.

As technology has evolved, thanks to the design of more optimized products, the development of new manufacturing processes and the introduction of new materials (such as new polymers, new fibers or incorporating emerging materials in its structure, as is the case with nanomaterials), composite structures for space applications have achieved even more remarkable performance4,5,6,7.

INEGI also at the forefront of innovation in Europe

Considering that space structures require maximum performance and the lowest possible weight, very high modulus carbon fibers gain special relevance and are today an important product oriented to the Space sector.

Space is a strategic sector for different nations, but there is still no European supplier of this type of carbon fiber. For this reason, these are identified as a critical material for European non-dependence in the space sector.

It is in this context that, in 2011, the FP7 EUCARBON8 project emerged, the first European unit (installed at Fisipe, now part of the SGL Group) the capacity to manufacture high module carbon fibers, a critical material for the manufacture of satellite structures. The properties of carbon fibers underwent an improvement process, in the scope of a subsequent project entitled H2020 SpaceCarbon9, with the aim of achieving higher elasticity modules. Additionally this project implemented the capacity to produce intermediate module fibers, used for the manufacture of launcher structures.

During the course of the project, which has the participation of AIRBUS Defense and Space and AVIO, INEGI developed new semi-products for composites (pre-impregnated), allowing the validation of the fibers developed and proposal of new matrices for the composites of the future. These involve modification with nanomaterials and the incorporation os new compounds that allow, for example, to improve thermal and electrical conductivities, fracture toughness and their behavior at cryogenic temperatures.

INEGI's contributions to the technological development of the sector, however, precede these projects, and one can highlight the participation in a set of ESA projects10,11, led by HPS GmbH, in order to explore the use of carbon nanotubes in structures for the space. Initiatives that culminated, in 2018, with the application of a demonstrating optical mirror12 that takes advantage of nanomaterials to improve the surface properties of composite structures, resulting in better machining, coating capacity, less roughness and better surface thermal and electrical properties.

Portuguese and European companies support knowledge creation

Among the various challenges embraced by INEGI is the RTM E-BOX13 project, in which an electronic box for Space was developed, using composite material and manufacturing in processes without using an autoclave, allowing to reduce weight in the structure and energy in the manufacturing process. Traditional composites do not have sufficient thermal dissipation and, therefore, INEGI's team of specialists created a new composite material, using a highly conductive carbon fiber. At the same time, they worked on the material architecture, in order to guarantee an adequate thermal dissipation and produced in a manufacturing process outside the autoclave, capable of guaranteeing a complex and highly demanding geometry.

Other challenges include the development of composites with a combination of materials and geometries made to measure for a two-grid composite reflector in the KuDGR14 project (led by HPS GmbH), and the COMETH15 project, led by INEGI and with the participation of SONACA, under which a new folding structure is being developed entirely in composite material capable of reducing weight by eliminating the mechanical components necessary for the structure.

The challenge here was to ensure a sufficiently stable structure during the three associated phases (folded structure, during deployment and during operation), which was achieved through an appropriate definition of materials and geometries, supported by the integration of micromechanical models, such as those described in a recent publication by the research team focused on the phenomenon of relaxation of these structures during prolonged storage16. These folding structures are of enormous importance today, as they allow large structures to be accommodated in the available launchers. INEGI has also been working on the development of support and test systems for these structures, in European reference projects at ESA and EC (European Commission) 17,18,19.

Portugal contributes to the «space race» in composites

Technological development in the area of materials and composite structures for the Space sector has been promoted essentially in a European context, but has been gaining more and more expression in Portugal. Examples of this are the projects in co-promotion with Spinworks (project DIVER20, for dimensioning thermal protection systems in composite for reentry capsules), FHP (project Filtube21, for development of composite tubular structures) and with Omnidea (project SSalut22, with the objective of developing composite pressure tanks with auto-sensory capacity).

Innovation continues, with INEGI's presence in projects about to start, as is the mobilizer VIRIATO23 (led by Omnidea) that aims to create new materials and manufacturing strategies for cryogenic microlance tanks, and NewSat24 (led by Stratosphere) where INEGI will develop innovative framework structures for microsatellites, based on topological optimization strategies, taking advantage of additive manufacturing and new composite semi-products.

Composite materials are, therefore, an important ally in space exploration, with technological challenges always present. Research and innovation promise to provide the answer, and future paths are designed with the use of new hybrid materials, moving towards multifunctionality, more efficient, automated manufacturing processes suitable for highly complex geometries or with the design of innovative structures, using advanced methodologies such as topological optimization, genetic algorithms or artificial intelligence.

[1] Naser, M. Z., & Chehab, A. I. (2018). Materials and design concepts for space-resilient structures. Progress in Aerospace Sciences, 98, 74-90.

[2] Bhat, Gajanan, ed. Structure and properties of high-performance fibers. Woodhead Publishing, 2016.

[3] Alemour, B., Badran, O., & Hassan, M. R. (2019). A Review of using conductive composite materials in solving lightening strike and ice accumulation problems in aviation. Journal of Aerospace Technology and Management, 11.

[4] Sudhin, A. U., Remanan, M., Ajeesh, G., & Jayanarayanan, K. (2020). Comparison of Properties of Carbon Fiber Reinforced Thermoplastic and Thermosetting Composites for Aerospace Applications. Materials Today: Proceedings, 24, 453-462.

[5] Zhang, X., Chen, Y., & Hu, J. (2018). Recent advances in the development of aerospace materials. Progress in Aerospace Sciences, 97, 22-34.

[6] Sairajan, K. K., Aglietti, G. S., & Mani, K. M. (2016). A review of multifunctional structure technology for aerospace applications. Acta astronautica, 120, 30-42.

[7] Gohardani, O., Elola, M. C., & Elizetxea, C. (2014). Potential and prospective implementation of carbon nanotubes on next generation aircraft and space vehicles: A review of current and expected applications in aerospace sciences. Progress in Aerospace Sciences, 70, 42-68.

[8] EUCARBON "European Space-Qualified Carbon Fibres and Pre-Impregnated Based Materials” (2011-2015) (FP7 Space - Technologies for European non-dependence and competitiveness)

[9] SpaceCarbon "European Carbon Fibres and Pre-Impregnated Materials for Space Applications” (2018-2021) (H2020 Space - Technologies for European non-dependence and competitiveness)

[10] NACO I "Non-conventional Matrix/Carbon Nanotubes Reinforced Composites for Applications in Space” (2007-2009) (ESA-GSTP)

[11] NACO II "Non-conventional Matrix/Carbon Nanotubes Reinforced Composites for Applications in Space” (2011-2013) (ESA-GSTP)

[12] NATAP "Carbon Nanotube Technology and Material Engineering for Various Space Applications” (2016-2018) (ESA-GSTP)

[13] RTM E-BOX "Thermally Conductive CFRP manufactured by Resin Transfer Moulding” (2013-2015) (ESA-TRP)

[14] KuDGR "Dual-Gridded Carbon Fibre Reinforced Plastic Reflector” (2011-2015) (ESA-ARTES)

[15] COMETH "Composite elastic hinge for Antenna Deployment Structures” (2017-2020) (ESA-ARTES)

[16] P. Fernandes, B. Sousa, R. Marques, João Manuel R.S. Tavares, A.T. Marques, R.M. Natal Jorge, R. Pinto, N. Correia, "Influence of relaxation on the deployment behaviour of a CFRP composite elastic–hinge”, Composite Structures, 2020, 113217.

[17] LEA "Large European Antenna” (2017-2021) (H2020)

[18] LEOB "Large Deployable Reflector for Earth Observation” (2019-2022) (ESA)

[19] CIMR "Copernicus Imaging Microwave Radiometer High Priority Candidate Mission” (2020-2025) (ESA)

[20] DIVER "Integrated Design of Re-Entry Vehicles” (2015-2018) (PT2020)

[21] Filtube "Non-conventional tubular composite material structures for space applications” (2016-2019)

[22] SSAluT3” Self-Sensing Aluminium Type III composite overwrapped pressure vessel” (2016-2019)

[23] Viriato "Reusable innovative vehicle for research and fostering orbital technology” (PT2020 Mobilizadores)

[24] NewSAT” Development of a compact integrated sensor and satellite for earth observation” (PT2020 / MIT Programme)