The satellite is built by OHB and will provide images with an extremely high level of detail. The main component is a large telescope. For this optical system, HENSOLDT is constructing a total of four mirrors of different sizes. The mirrors are made of Zerodur, a glass ceramic with very low thermal expansion.
After the largest mirror was light weighted at Schott for more than half a year, it was polished at Zeiss for more than a year and interferometrically measured at HENSOLDT more than 50 times to achieve the required accuracy in the nanometer range. For comparison: a hair has a diameter of about 100µm, which is 1000 times more than the required and achieved height differences on the mirror surface.
For HENSOLDT, achieving this size with this accuracy is a first. There are very few companies in the world capable of manufacturing such mirrors. It requires an end-to-end understanding of the relationships between prediction, manufacturing and measurement, which has been refined during the manufacturing process. To prove that the mirror assemblies survive the challenging environmental conditions of rocket launch and operation unscathed, HENSOLDT conducted numerous tests for vibration, shock, thermal stress and high-energy radiation.
Since 2019, a total of five units of these mirrors have been developed, manufactured, assembled and tested, three of which are flight units. The unit for the telescope tests was already delivered in October 2020 and successfully tested in OHB’s instrument.