XMM Flight Model Mirror Module Testing Y. Stockman, P. Barzin, H. Hansen, E. Mazy, J. Ph. Tock CSL – University of Liège B- 4031 Angleur, Belgium email : ystockman@ulg.ac.be D. de Chambure, R. Lainé ESA / ESTEC PO BOX 299, 2200 AG Noordwijk, The Netherlands D. Kampf Kayser Threde Wolfratshauser Str., 48, D-81379 Munich, Germany R. Banham, M. Canali, G. Grisoni, P. Radaelli Media Lario, Località Pascolo I-23842 Bosisio Parini (LC), Italy ABSTRACT In the frame of the X-ray Multi Mirror Mission (XMM), the second European Space Agency (ESA) cornerstone project, in total five Flight Models of the Mirror Module have been built. The Mirror Modules are the optical heart of the satellite. Each Mirror Module contains 58 X-ray optical quality Mirror Shells which have been produced and integrated by Media Lario. Each of these Mirror Modules has been tested in the Centre Spatial de Liège (CSL) FOCAL-X facility. The goal of these tests was to measure the optical performance of the Mirror Modules under simulated launch and in-orbit configurations, and to perform some calibration on the Mirror Modules. To achieve these goals, a full EUV (58.4 nm) collimated beam is used to assess the optical characteristic in a representative flight configuration. The X-ray performance is controlled by means of an X-ray pencil beam and an X-ray collimator. The pencil beam is used for the determination of the Mirror Shell position, wing scattering and X-ray reflectivity measurements, the later one for the effective area measurement over 1.5 to 8 keV energy range. This paper mainly deals with the latest results achieved on the Flight Model 4 Mirror Assembly and the fifth Flight Mirror Module. The first one is integrated on the spacecraft, the second has been built to serve as an additional spare flight MM of the highest quality and to further develop the mirror module production and measurement process. After the presentation of these test results, the lessons learnt from the manufacturing and the testing of the mirrors will be presented. KEYWORDS: X-ray optics and telescope, EUV optics, test facility, XMM. 1. INTRODUCTION By the end of 1999, the X-ray Multi-Mirror Mission (XMM) 1 will be launched on an Ariane V rocket. XMM is an observatory mission that will operate in the 0.1 to 10 keV range of the electromagnetic spectrum. It is the largest scientific instrument ever built by ESA. Due to its exceptional large collecting area, it will provide unprecedented observation of X- ray sources. To meet this unique challenge, the optical heart of the mission 2 consists of 3 Mirror Assemblies (MA). Each MA includes a Mirror Module (MM) containing 58 electroformed X-ray quality Mirror Shells (MS) and X-ray and optical baffle (XRB and entrance baffle) to reduce stray light. Two of the three MA are equipped with a Reflection Grating Assembly (RGA) for spectral analysis.