3D-Printed Aluminum Mirrors Pave Way for New Era in CubeSat Optics

Researchers in the United Kingdom have developed a novel method for producing lightweight, flexible aluminum mirrors specifically for CubeSat telescopes. This additive manufacturing technique aims to significantly reduce the mass of primary mirrors, targeting approximately a 60% weight reduction compared to traditional designs. This advancement is expected to enhance the capabilities of these small, versatile satellites, opening new possibilities for space exploration and observation.

The newly developed mirror features an annular design with an external diameter of 84 mm and an internal diameter of 32 mm. Its internal structure incorporates a "split-p internal lattice," resembling a honeycomb, engineered to increase robustness while drastically reducing weight. Finite Element Analysis (FEA) modeling predicted a weight reduction of around 56%, closely aligning with the project's 60% objective. The manufacturing process utilized laser powder bed fusion (LPBF) with AlSi10Mg aluminum alloy. Post-processing steps included Hot Isostatic Pressing (HIP) to minimize internal porosity and single-point diamond turning to achieve a highly reflective surface.

Analysis using X-ray Computed Tomography revealed minor pores, predominantly at the perimeter where laser paths converge. Surface roughness measurements remained below 8 nm for all samples. HIP-treated samples exhibited slightly increased roughness compared to those that underwent diamond turning. While the HIP process effectively reduced internal porosity and enhanced strength, it also led to a marginal increase in Total Integrated Scatter (TIS) values due to the heightened surface roughness.

Future development will involve applying a chromium optical coating to further refine the surface quality and conducting thermal flexibility tests to assess performance under simulated space conditions. The increasing demand for cost-effective, durable, and lightweight mirrors is a driving force behind this research, marking a crucial step forward in the advancement of CubeSat technology and space optics. This innovation offers a pathway to more capable and accessible space missions, enabling a new generation of scientific instruments and observational platforms.