As a supplier to the aerospace industry our client was involved in one of the most exciting fields of engineering. They produced sun sensors for satellite guidance and for the navigation of planetary rovers. They came to us to solve a problem that could stop the project from getting off the ground.
The client: They produced sun sensors for satellite guidance. They came to us to solve a problem that could stop the project from getting off the ground.
The challenge: A sun sensor is designed to detect the exact angle of the sun relative to the satellite. The design required an opaque coating on the surface of a filter. Light passes through lines etched through the coating, and is then analysed by a CCD chip behind the filter.
Light was entering the filter from other sources and causing false readings.
The solution: We found stray light was entering the module from two sources:
Pinholes in the coating were caused by dust particles on the substrate. Extra cleaning would have been expensive, but we applied lateral thinking and came up with a solution that produced perfectly pinhole-free coating on an entirely standard coating plant.
Stray light from the perimeter was being scattered from the ground edge. Edge blackening was ineffective, so we applied an ring of chrome coating to the sapphire cover plate above the filter.