Johan Leijtens - fine sun sensor BiSon74-ET-RH (ITAR free, extended temperature)After 1.5 years of intensive development and testing we formally came to conclusion of the Artes 5.2 project ITAR free extended temperature sunsensor today by performing a final presentation.

Based on inputs gathered from several potential suppliers over the years, the project started as a company internal project some 3 years ago. The main problem these sensors are intended to solve is that for satellites with extendable solar panels, the panels are often blocking part of the sunsensors field of view in the stowed configuration.

A sunsensor mounted on the solar panel itself will avoid this obscuration (thus improving early orbit acquisition) but will require a sunsensor capable of surviving a much wider temperature range than currently available on the open market. This in turn will require some unconventional solutions.

Based on supportletters provided by SSTL and TAS, the Artes 5.2 program was intended to be (and has been) a very serious risk mitigation exercise. Without the provided ESA support, it would not have been possible to do all these pre-developments is such an extensive way. As a result we are now confident that the next batch of sensors will survive the space environments associated with even the most demanding missions.

This is not only due to the fact that we could show through test that the sensors will survive temperature cycling over a +125 to -125 degrees C temperature range, 30g sine, 48g random and 10.000g pyro-shock testing, but in addition to that, during a design change the radiation shielding is increased to 3mm equivalent circumferential shielding. This means that in combination with diodes tested to more than 1Mrad and 10^16 1MeV electrons, the sensors are capable of surviving many years  near the van Allen belts.

This last property seems to become more and more important as sunsensors cannot be shielded from radiation given the fact that the are on the exterior of the satellite, and a number of large constellations are planned at orbit ranging from 1000 to 1500km.

Before we will start the design of the final configuration we would like to consult our potential customers though so as to tune the properties of our sensors to the demands of our customers as good as possible. This will probably be done at that IAA smallsat conference in Berlin, the ESA GNC conference in Salzburg and potentially even the smallsat in UTAH (although these inputs may come a bit late)

We invite everybody that wants to contribute to building the specification of at least one of the sunsensors for the future by sending remarks, questions or just a list of desired specifications to