A sun sensor determines a spacecraft’s orientation with respect to the sun.
The front surface of the NewSpace Systems (NSS) NFSS-411 sensor is a synthetic sapphire window with a reflective metal coating beneath. Slits are etched in the metal and sunlight passes through them and through an optical filter onto a sensor. The charge on the photo-sensors are read by the micro-controller which processes the image and computes the sun vector. The vector and other telemetry is returned to the spacecraft through the serial interface.
The NCSS-SA05 is base around a PSD analogue sensor. Each sensor comes with a specific calibration equation for maximum accuracy. The unit can be powered from unregulated DC power from the spacecraft.