Advanced Materials Technology, Inc (AMTI) responds to the NASA solicitation S2 "Advanced Telescope Systems" under subtopic S2.05, "Optics Manufacturing and Metrology for Telescope Optical Surfaces". The proposed program is aimed at developing large, ultra-lightweight mirror substrate, including membrane optics for very large aperture space telescopes. The novel materials offer considerable weight and cost savings. In order to prevent significant figure error, mirror substrate materials should have very low (ideally zero) coefficient of thermal expansion (CTE), low coefficient of moisture expansion (CME), low cure shrinkage, low internal stresses, low outgassing, and high thermal and environmental stability. The ultimate goal of the proposed Phase I program is to develop thin mirror substrate materials that will meet the desired requirements. Once the feasibility of the proposed technology is demonstrated in Phase I, we shall scale-up the thin mirror substrate technology in a Phase II program to meet the NASA requirements.