Lightweighting design optimisation for additively manufactured mirrors

Abstract

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An additive manufactured CubeSat mirror incorporating a novel circular lattice

“…Figure 1 highlights one of the polished AM mirrors and a cross-section demonstrating the lightweight design -a thorough description of the internal design is provided in Atkins et al (2019b). 18 The mirror dimensions were 84 mm diameter, 17.3 mm in height and with a spherical concave optical prescription of 350 mm radius of curvature. To reduce weight, a body centred cubic (BCC) lattice was used within the internal cavity, which reduced the weight to ∼ 69% of a solid equivalent.…”

“…The mirror dimensional requirements are based upon a nano-satellite (nanosat; CubeSat) payload structure designed for Earth observation (EO) and builds upon previous AM mirror development for CubeSats. 17,18 This paper will present the mirror requirements (mechanical and optical) for the design (Section 2), the first iteration of the mirror design incorporating a novel circular lattice (Sections 3 and 4), subsequent iterations of the design to ensure compliance with build guidelines (Section 5), analysis using a finite element model (Section 6) and concluding with a summary and and description of future work (Section 7).…”

Additively manufactured mirrors for CubeSats

“…The four substrates were built in the vertical orientation, as shown in Figure 5, with external support material added to the substrates to provide both support and heat dissipation -a thorough description concerning build orientation selection can be found in Atkins et al 2019 . 12 Following build completion the excess powder was removed and the substrates were thermally cycled before separation from the build plate to relieve stress within the build. In the final stage, the support material was removed from the substrate -tooling marks in Figure 5 right highlight where the support material has been removed around the spigot.…”

“…Future work will target two areas: design optimisation and improvement of the AM material. The sister paper Atkins et al 2019 12 described the design logic and performance of the fabricated mirror design. The percentage of mass remaining after lightweighting of the fabricated design was ∼ 69%, this value does not represent a significant weight saving at this stage; however, the priority of the project was the fabrication process chain of the AM mirrors the optical quality that could be achieved.…”

“…A single lightweighted design was used for the AM mirrors, based upon a 3 U Earth observation CubeSat, is described in Section 2. A thorough description of the AM mirror design and routes for future design optimisation is given in the sister paper Atkins et al 2019 , 12 which presents the design study of the UKSA project. The fabrication process chain is presented in Section 3.…”