On-Demand Additive Manufacturing of Astronomical Mirrors

The proposed technology will meet the Air Force’s need for new techniques to allow 3D printing at nanometer scales to produce astronomical parabolic/spherical mirrors requiring little to no figuring or modification to achieve the form fidelity, surface finish, and reflectance. Astronomical mirrors are traditionally produced via a combined casting, diamond turning, and coating approach that is time consuming, expensive, and yields a heavy cumbersome solid mirror structure for large numerical apertures. Additionally, when attempts have been made to lightweight these large mirrors, the centrifugal forces from diamond turning leads to residual stresses and distortions in the mirrors optical properties. The proposed technology is a two-step on-demand manufacturing approach to directly print and finish lightweight astronomical mirrors. Additive manufacturing will produce the mirror platform and non-contact electrochemical polishing will be used to create the mirror surface. Once the methodology to produce high quality mirrors is understood, we will evaluate the potential of incorporating support structures that can greatly reduce the weight of the mirror. As the successful completion of this activity, the manufacturing lead times and the cost to produce lightweight astronomical mirrors of interest to the Air Force, Space Force, and our commercial partners will be greatly reduced.