Silicon-Carbide, Pointing and Stabilization Mirror Assembly for Geostationary-Earth-Orbit Mission

High spatial resolution imagery from geo-stationary orbit places uncompromising demands on spacecraft stabilization and optical system thermal stability. GEO requires + 8.80 pointing FOR, 1.25 urad IFOV (10's of urad accuracy) and < 1 urad (rms) jitter at ~ 10 Hz rate. Prior solutions have combined complex and costly ACS/IMU/Stellar control of spacecraft jitter with detector oversampling and image motion compensation (IMC). The problem is heightened for limited weight MicroSpacecraft sensors with increased excitation bandwidth and lack of on-board control capability. Ultra-lightweight, thermally stable silicon carbide optics and advanced servo control systems permit large aperture pointing and high precision stabilization in one lightweight assembly. The core innovation of combining these technologies removes the tight slewing and jitter requirements from the spacecraft and IMC from the ground station; complexity, weight and cost are dramatically reduced. This program will develop a 0.5m aperture, high precision SiC pointing and stabilization mirror assembly including servo control electronics. Phase I will provide the conceptual design and analysis of a prototype unit and a hardware demonstration of an advanced 6" x 9" SiC mirror in an existing 2 urad pointing system. The closed back SiC mirror, replacing a beryllium mirror, has superior thermal stability, stiffness and strength. Phase II will provide the development and test of a flight qualifiable advanced pointing assembly for GEO; a wide range of micro-spacecraft such as Quick LAWS and commercial remote sensors and imagers are supported.