European Space Agency

BiSon74-ET-RH ITAR Free Extended Temperature Fine Sunsensor


The project entailed risk mitigation in the frame of the development of a fine sunsensor capable of surviving an unprecedented temperature range. Availability of such a sensor will allow to measure the sun’s attitude with respect to the solar panels directly even in stowed configuration. Next to this, by increasing the radiation tolerance over the currently available BiSon64 sunsensor, this sensor will be suitable for missions that operate a prolonged time in or near the earths van Allen belts like some planned telecom megaconstellations.


The main challenges are to selecting materials and glues that will allow to sustain the required temperature cycling both during on-ground testing and in-orbit operations, while being strong enough to withstand the mechanical loads experienced during launch. A second challenge is to demonstrate the feasibility to use ceramic injection moulding to reliably make high accuracy parts for space applications.


The BiSon74-ET-RH is intended for mounting on an extendable solar panel, thus measuring the attitude angle with respect to the sun directly  both in stowed and deployed configuration. This will ease and improve the reliability of sun acquisition both in LEOP and save mode phases of any mission. Next to this the high radiation tolerance will allow operation in high radiation environments for a prolonged period of time providing a more cost effective alternative to currently qualified products.


The sensors exhibit:

  • Unprecedented temperature range.
  • Low mass and profile
  • Less albedo sensitivity than a coarse sunsensor
  • Higher radiation tolerance than a coarse sunsensor
  • Guaranteed accuracy on basis of the use of a formula only
  • Very good quality to cost ratio

System Architecture

Titanium housing and ceramic injection moulded insert approach to match CTE’s to the largest extend possible and avoid glass transitions.


The project has known four phases:

1) trade-off and design

2)manufacturing and engineering tests on proto units

3) redesign

4) manufacturing and test of second series of proto units.

Current status

The Artes 5.2 project has been completed.

BiSon74-ET-RH tested through thermal vacuum cycling (12 thermal cycles -125°C..+125°C) Vibration tested (30g sine, 48g random) and pyro-shock tested (3000g and 10.000g) successfully. This has shown the survivability of the units despite the fact that some modifications are needed to reach an optimum configuration.

Minor modifications on the glue system and related partial tests are therefore anticipated before production and qualification of the final devices can be started.

Status date

Monday, May 8, 2017 - 08:15