AN X-RAY MIRROR ASSEMBLY FOR XMM-BASED ON CARBON-FIBER TECHNOLOGY

On the next cornerstone mission of the ''Horizon 2000'' programme of t he ESA scientific directorate, the X-ray Multi Mirror Mission (XMM), t he most crucial elements are the three X-ray mirror assemblies. Each c omprises 58 nested Welter type I mirror pairs (paraboloid/hyperboloid) , their supporting structure, and a thermal baffle. In an ambitious te chnology programme ESA has initiated the development of two alternativ e technologies based on nickel and carbon fibre epoxy substrates for t he mass production of the mirrors. This paper describes the conceptual design and the analytical results achieved in the course of a system study by Dornier and Zeiss on the overall design of the Mirror Assembl y based on the carbon fibre epoxy technology. The overall design of th e Mirror Assembly was verified by the manufacture of an Optical Demons tration Model which, in essence, proved feasibility of its design, int egration and performance. However, late results from X-ray tests of th is unit revealed also the necessity to further improve the design with respect to performance sensitivity of the mirrors against moisture co ntent in the substrate material. Respective design modification are cu rrently in progress.