Selective laser melting, referred to as "Direct Metal Laser Sintering"(DMLS), "Metal Powder Bed Fusion" or "3D Printing" is an additive manufacturing process which allows extremely thin wall and complex structures. Off-axis aspherics are as easily produced as simple spherical optical surfaces.Nickel 11-13 % phosphorus alloy is the only hard, very fine grain, corrosion resistant material that can be diamond turned and polished to ultra smooth surfaces. Diamond turning produces any aspheric surface to visible optical tolerances. Finishes of 0.6nm rms have been diamond turned on NiP alloy without post polishing. Very low cutting force of diamond turning allows a mirror faceplate to be very thin without print-through of the internal support structure. The innovation uses proven steel, stainless steel and superalloy powder additive manufacturing to make mirror substrates with near perfect thermal expansion match with electroplated NiP coating. It is fabrication of low cost, light weight large aperture mirrors by three processes. 1. Additively manufactured mirror substrates very close to net shape. 2. Electroplated NiP alloy covers contours of the mirror substrates with thickness to allow diamond turning, no machining of mirror substrate required. 3. Diamond turning can produce the mirror segment contour to visible tolerances.
Potential NASA Commercial Applications: (Limit 1500 characters, approximately 150 words) Initial medium aperture off-axis three mirror anastigmat (TMA) mirror optical components, collimator and telescope optical instruments. As size capability increases, larger off-axis TMA optical collimator and telescopes. Off-axis hexagonal periphery aspheric optical mirrors can be assembled to enable very large telescopes.
Potential NON-NASA Commercial Applications: (Limit 1500 characters, approximately 150 words) Defense applications requiring mirror optical components for satellites and aerospace vehicles. Non-military applications such as weather satellite optical mirrors and commercial telescope optics. Commercial applications requiring light weight stiff optical components such as semiconductor manufacturing equipment.
Technology Taxonomy Mapping: (NASA's technology taxonomy has been developed by the SBIR-STTR program to disseminate awareness of proposed and awarded R/R&D in the agency. It is a listing of over 100 technologies, sorted into broad categories, of interest to NASA.) Infrared Long Mirrors Multispectral/Hyperspectral Non-Electromagnetic Optical/Photonic (see also Photonics) Telescope Arrays Terahertz (Sub-millimeter) Ultraviolet Visible
