PROBA-3
The European Space Agency (ESA) mission
An artificial solar eclipse created in orbit by two satellites
Creotech’s role: the optical instrument’s computer and the satellite test system
Solar storms eject enormous amounts of energy and matter into space. Particles reaching Earth can damage satellites, disrupt radio communications and threaten power grids. To better predict these phenomena, we need to understand their source: the solar corona. The problem is that it is about a million times fainter than the Sun’s disc and can only be fully seen from Earth during a total solar eclipse.
PROBA-3 solves this problem in a remarkable way. Two satellites fly in formation, approximately 150 metres apart, maintaining their relative position with an accuracy of less than a millimetre. The first of these, Okulter, obscures the Sun’s disc, whilst the second, Koronograf, photographs the corona at the same time. In this way, an artificial eclipse is created in orbit, which can be repeated many times and observed for much longer than a natural one. The mission transmitted its first images of the corona in June 2025.
Creotech Instruments, in collaboration with the Space Research Centre of the Polish Academy of Sciences, designed and manufactured the optical instrument’s computer subsystem and the satellite testing system. We also designed the AEU electronics board, which forms part of the coronagraph controller. All work was carried out in our cleanrooms, in accordance with procedures approved by the ESA. The technologies being tested on PROBA-3, such as precision manoeuvres to approach another object in orbit, may in future be used, amongst other things, to remove space debris.