On the testing and validation of stray light attenuation for microsatellite star tracker baffles

Abstract

This thesis describes strategies to perform stray light testing in an earthbound laboratory while accounting for atmospheric and surface scattering phenomena that make these measurements difficult. We present a method to analyze and predict the stray light performance for a baffled star tracker optical system. This method involves a hybrid stray light analysis procedure that combines experimental measurements of a star tracker lens optics and uses ray-tracing to obtain attenuation curves. We demonstrate these analytical techniques using an engineering model ST-16 star tracker from Sinclair Interplanetary along with a baffle prototype. The system attenuation curve's accuracy is validated by comparing independently measured baffle attenuation curves with equivalent ray-tracing models. Additionally, exclusion angles are defined for the ST-16 sensor by calculating the false detection rate that varies with system attenuation levels. These techniques provide a versatile alternative to conventional testing for preliminary design stages for a star tracker baffle that emphasizes the use of modest infrastructure.