Developing in orbit manufacturing methods for sustainable composites for space applications

Sustainability is becoming an increasing concern for the space industry as it grows. However, the strict performance requirements of the space application arising from mass and environmental constraints pose a significant challenge. Current spacecraft are made using non-recyclable materials and are either demised or written off at their end-of-life. This solution has been satisfactory for earth-orbiting missions; however, in-situ use/reuse of existing material may become obligatory for long-duration or indefinite missions.

This project aims to develop and investigate an in-orbit manufacturing method as a potential alternative to the current paradigm. A successful method could unlock the ability to create large, efficient structures without the penalties associated with the launch and manufacture of virgin material. While the scope of this PhD is primarily focused on space applications, such a method could also have significant implications for the terrestrial sustainability of composites, which are currently widely used in the aerospace and wind energy sectors.

The proposed concept combines the WrapToR manufacturing method's structural efficiency with discontinuous fibre composite's recyclability and performance enabled by the HiPerDiF alignment process. To date, no group has demonstrated a system simultaneously capable of comparable structural efficiency and recyclability.

To develop this concept, the project aims to tackle the following challenges: 1. Identify and develop a discontinuous fibre thermoplastic composite suitable for space application and manufacturing. 2. Develop a method capable of consolidating aligned HiPerDiF tapes and thermoplastic into a usable filament feedstock. 3. Modify the WrapToR process to be compatible with a thermoplastic input material.

There are seven principal groups of beneficiaries for our new EPSRC Centre for Doctoral Training in Composites Science, Engineering, and Manufacturing.

1. Collaborating companies and organisations, who will gain privileged access to the unique concentration of research training and skills available within the CDT, through active participation in doctoral research projects. In the Centre we will explore innovative ideas, in conjunction with industrial partners, international partners, and other associated groups (CLF, Catapults). Showcase events, such as our annual conference, will offer opportunities to a much broader spectrum of potentially collaborating companies and other organisations. The supporting companies will benefit from cross-sector learning opportunities and

- specific innovations within their sponsored project that make a significant impact on the company;
- increased collaboration with academia;
- the development of blue-skies and long-term research at a lowered risk.

2. Early-stage investors, who will gain access to commercial opportunities that have been validated through proof-of-concept, through our NCC-led technology pull-through programme.

3. Academics within Bristol, across a diverse range of disciplines, and at other universities associated with Bristol through the Manufacturing Hub, will benefit from collaborative research and exploitation opportunities in our CDT. International visits made possible by the Centre will undoubtedly lead to a wider spectrum of research training and exploitation collaborations.

4. Research students will establish their reputations as part of the CDT. Training and experiences within the Centre will increase their awareness of wider and contextually important issues, such as IP identification, commercialisation opportunities, and engagement with the public.

5. Students at the partner universities (SFI - Limerick) and other institutions, who will benefit from the collaborative training environment through the technologically relevant feedback from commercial stakeholder organisations.

6. The University of Bristol will enhance their international profile in composites. In addition to the immediate gains such as high quality academic publications and conference presentations during the course of the Centre, the University gains from the collaboration with industry that will continue long after the participants graduate. This is shown by the

a) Follow-on research activities in related areas.
b) Willingness of past graduates to:

i) Act as advocates for the CDT through our alumni association;
ii) Participate in the Advisory Board of our proposed CDT;
iii) Act as mentors to current doctoral students.

7. Citizens of the UK. We have identified key fields in composites science, engineering and manufacturing technology which are of current strategic importance to the country and will demonstrate the route by which these fields will impact our lives. Our current CDTs have shown considerable impact on industry (e.g. Rolls Royce). Our proposed centre will continue to give this benefit. We have built activities into the CDT programme to develop wider competences of the students in:

a) Communication - presentations, videos, journal paper, workshops;
b) Exploitation - business plans and exploitation routes for research;
c) Public Understanding - science ambassador, schools events, website.