The aim of the Optical Coatings for Ultra Lightweight Robust Spacecraft Structures (OCULUS) project is to demonstrate the process of a high-quality metallization of carbon-fibre-composite substrates. Thereby the creation of space-suitable, lightweight and cost-effective refractor is enabled, which allows a drastic mass reduction of mirrors in the application for space telescopes.
Conventional telescopes for operation on ground and in space use mirror materials with high density, such as metal or ceramics. The mirror mass of space telescopes dominates the system mass. The aperture’s diameter, which is relevant for the optical performance of the system, is limited by the launcher. The reduction of mirror mass is also of interest for ground based observatories. Through the research in the OCULUS project the mirror mass can be reduced by a minimum of 80% compared with conventional systems.
In cooperation with Invent GmbH and the Fraunhofer Institute for Surface Engineering and Thin Films, the Institute of Space Systems came in second within the Innospace Masters Contest in the category "DLR Space Administration Challenge". Thus the manufacture of a prototype for technology demonstration is possible.
The Invent GmbH already has experience in manufacturing geometrically high precise CFRP sandwich structures. This components are very stiff, extremely temperature resistant and can be produced in different sizes even with aspherical shape. The Fraunhofer IST is responsible for the highly adhering coating by means of galvanic metallization and subsequent the highly accurate polishing. Besides the project coordination the Institute of Space Systems take over the implementation of the technology in a space telescope in CubeSat size.
The optical system is designed for Earth observation. For improved performance, with enlargement of the aperture on approx. 260 mm diameter, the primary mirror has to be segmented and deployed as well as adjusted autonomously. The experience and technology gathered in this project can be applied to other applications, where high precise CFRP structures with a metallic surface functionality (optical, electrical, tribological) are needed.