The Things You Can’t Ignore: Evolving a Sub-Arcsecond Star Tracker

The feasibility of a star tracker with 1 arc-second accuracy and 1 deg/sec slew capability is explored, using the ST-16 design as a starting point. Whole-sky simulation is used to determine the impact of optical design on the star tracker availability. The current optical calibration process is examined, and shown to be inadequate for the desired performance. Additional factors that become important at high accuracy are examined. These are detector calibration, temperature variation, chromatic aberration, stellar aberration and proper motion. Plausible methods of dealing with each of these are presented