SSBV Fine Sun Sensor

The Fine Sun Sensor determines spacecraft body angles with respect to the sun. It accepts configuration commands and outputs digital angles and telemetry over a serial interface to the on-board computer, powered from unregulated DC power. The front surface is a mirror with slits cut in the reflective metal; sunlight passes through these slits and an optical filter onto an array of photosensors interfaced to a micro-controller, which processes the image and computes the sun vector.

Applications include accurate sun-angle determination (four sensors can achieve full sky coverage), use alongside a magnetometer for simple attitude control, and as a safe-mode sensor on gyro or star-mapper controlled systems. Qualification heritage comes from 14 on-orbit sensors flown on 4 LEO satellites.