NSS Fine Sun Sensor


The sun sensor determines the 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. The unit is powered from unregulated DC power from the spacecraft.

The front surface of the sensor is a mirror with slits cut in the reflective metal. Sunlights passes through these slits and then through an optical filter. Below this is an array of photosensors interfaced to a micro-controller.

The charge on the photosensors 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.

  • Features
  • Performance
  • Product properties
  • Qualification
  • Documents
  • Accurate determination of sun-angle
  • Four sensors can achieve full sky coverage
  • Used in conjunction with a magnetometer or simple attitude control
  • Can be used as saf°e-mode sensors on gyro or star-mapper controlled systems
  • Digital architecture
  • High accuracy
  • Wide field of view
  • Small size and mass
  • Low power
  • Simple to interface
  • Field of view 140°
  • Update rate 5 Hz
  • Accuracy +/- 0.1°
  • Digital I/F: UART, SPI, I2C, CAN or RS-485/422
  • Mass: 35 grams
  • Power: 7.5 mA average, 26 mA peak
  • Size: 34 mm x 32 mm x 21 mm
  • Operating temperature: -25°C to + 50°C
  • 15g rns random, 1000g shock (qualification levels)
  • 10krad total dose (component level)
  • Power Supply: 28V DC nominal ( 5V to 50V)

The NFSS-411 was first flown in 2007. Since then, it has been used on a number of constellations with a total of over 100 delivered. The NCSS-SA05 has also been delivered, more than one hundred units, to a multitude of international satellite programmes.