Star Trackers Based Upon Advanced Sensor Technologies

"Modern star trackers are based primarily upon Charge-Coupled Device (CCD) image sensors. CCDs are sensitive to the space radiation environment and can degrade rapidly under the influence of energetic charged particles and x-ray and gamma-ray photons.Recently, new types of image sensors have been developed that show promise of being more radiation-tolerant than CCDs. These Active Pixel Sensors (APS) are based on complimentary metal-oxide semiconductor (CMOS) processing can also include on-chipanalog-to-digital converters, on-chip correlated double sampling, and addressability of individual pixels. A back-illuminated CMOS imager can combine the advantages of CMOS arrays with the sensitivity and uniformity advantages of the highest quality CCDarrays. This Phase I study will address the development of a back illuminated CMOS array for star tracker and other high performance applications, ending with the conceptual design for a back-illuminated CMOS array. In Phase II the design will becompleted, fabricated and evaluated. The anticipated benefit of Phase I is a star tracker conceptual design that affords greater radiation tolerance and lower cost without sacrificing performance. The prospect of reduced cost and improved radiationtolerance will make the proposed CMOS based star tracker attractive to DOD, NASA and commercial spacecraft manufacturers. There may be a broader market for star trackers as a backup for GPS navigation systems wh