Description: Our proposed innovation is additive manufacturing for the production of lightweight mirror substrates for flight applications with high mechanical stability. The steps of our proposed process for manufacturing lightweight 3D printed mirrors: first, a geometrically complex substrate is easily and cost-effectively manufactured using 3D printing. After printing, the mirror surface is lapped and polished using traditional manufacturing methods to final figure specifications. Then, a flight or space ready mirror coating is applied to the surface and the part is tested for performance. Additive manufacturing will permit lightweight mirrors with support structures that are impossible with traditional manufacturing methods for lightweighting. In addition, these structures will be optimized in size, shape, and location to negate thermal effects from changes in temperature and mechanical effects from stresses during manufacture, mounting, and flight. Technical Objective 1: Demonstrate feasibility of additive manufacturing a lightweight substrate with mechanical and thermal stability at flight temperatures Our goal for this objective is to manufacture a spherical mirror substrate suitable for light focusing applications at a range of temperatures for flight applications Technical Objective 2: Demonstrate feasibility of depositing mirror coatings at low temperatures for flight applications A low temperature deposition process minimizes shape distortion of the 3D-printed substrate that would occur during a typical coating. Our work plan consists of the following tasks: 1: Mirror Substrate Design and Optimization 2: Manufacturing of the Optimized Mirror Substrate using 3D printing 3: Polishing the Mirror Substrate 4: Low-Temperature Deposition of Mirror Coatings on Substrates for Flight Applications

Benefits: Many missions in space and sub-orbital atmosphere require lightweight telescope systems for imaging applications. The planned New Horizons Mission to Pluto is such an example that requires a lightweight telescope system. The NASA's Next Generation X-ray Optics (NGXO) project is an example of a need for a lightweight x-ray mirror system. Balloon missions are a specific application that would be perfect for lightweighted 3D printed mirrors. Balloon missions are highly recommended for next generation observatories. Additionally, the Astro2010 report identified that lightweight mirrors for both x-ray and UV/Visible applications are necessary for several different future missions. A lightweighted 3D printed optic could dramatically change the design space for the mirror in these missions.

Mirror-coated 3D printed optics can be used for airborne laser systems. Firing an airborne laser is significantly cheaper than firing an anti-missile missile. In addition, there is no recoil or after effect. However, to make airborne power lasers realizable to many applications, a weight reduction of the laser system is required. A reduction in weight increases the available time in flight as well as improves the speed and accuracy of tracking. It has been estimated that the optical assembly may comprise 40-50% of the total weight of the laser system. Thus, a significant opportunity exists to advance airborne lasers by reducing the weight of the optical assembly. Freeform optics are quickly becoming part of many commercial and military optical systems. Many optical designers are starting to use freeform optics to achieve optical performance (less aberrations), lighter weight optical systems through a reduced number of components, and an increased ability to go off axis with smaller and tighter packages. Optimax is starting to offer commercial quality freeforms as a standard component. We are seeing designs for beam shaping, corrector plates, conformal windows, and head-up displays for example. 3D printing of mirror substrates for freeform optics would expand the design space possible.