Additive Manufacturing Techniques for Astronomical Mirror

TECH FOCUS AREAS: Directed Energy TECHNOLOGY AREAS: Space Platform OBJECTIVE: This topic's outcome will be ability to create a telescope mirror not requiring much/any figuring to be usable for observing space objects. DESCRIPTION: Efforts will aim to develop techniques/technologies to allow 3D printing at nanometer scales to produce parabolic/spherical mirrors requiring little to no figuring or modification. Visible light is in the range of 400 - 700 nm and typical figuring of astronomical telescopes is to the wavelength/10 or better. Achieving this level of figuring with a 3D printer will require either the ability to print at the nanometer scale, or some technique to get the nanometer figure at a larger print scale. The Air Force is looking for a solution eventually providing the ability to mass produce custom size/shape mirrors for use in telescopes supporting Space Domain Awareness at reduced costs and at lighter weights to improve performance. PHASE I: Investigate the capabilities of various Additive Manufacturing devices and techniques for micrometer-to-nanometer-scale accuracies. Research how those capabilities could be improved to provide required accuracy to 3D print a quality mirror. Research various printing materials providing the strength required for a size-able mirror to retain its shape when used in a telescope. Investigate techniques to make the process scalable; being able to 3D print a meter-class mirror for a telescope could provide additional opportunities for successful technology transition. PHASE II: The contractor will demonstrate the ability to 3D print a high-quality mirror that can be used for astronomical purposes by printing an 8-inch mirror with an approximate focal length of 840mm (F/4 focal ratio) and a surface figure of wavelength/10 (./10). The mirror will be assembled into a Newtonian telescope design to demonstrate its ability to hold its shape in actual use. The contractor will, in the course of this phase also demonstrate the tradeoffs of time to print vs. the quality of the printed mirror (./4 vs. ./10 figuring). The contractor should make contact with telescope manufacturers during this phase to garner interest in their technique/potential products. The resulting telescope will be provided to the Space Force for evaluation under normal operations. PHASE III DUAL USE APPLICATIONS: The contractor will demonstrate the scalability of the technology/techniques to a twenty-inch mirror with wavelength/10 figure. For dual use potential: Recently there has been a shortage of commercial, hobbyist telescopes due to supply issues from non-indigenous manufacturers. This capability could relieve this shortage. REFERENCES: https://3dprint.com/238521/nanofabrica-micron-resolution-3d-printing-platform/ https://www.energy.gov/science/bes/articles/how-3d-print-nanoscale https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202001675?af=R https://www.researchgate.net/publication/341454859_3D_Printing_of_Micrometer-Sized_Transparent_Ceramics_with_On-Demand_Optical-Gain_Properties KEYWORDS: Additive Manufacturing; Telescope Mirrors; 3D Printing; Astronomical Mirrors; Nanometer scale