Environmental testing of XMM-Newton optics

XMM-Newton is the largest space observatory ever built and launched by the European Space Agency (ESA). The images recorded during its first year in orbit demonstrated all the high-quality and correct work undertaken on ground. This paper deals with the most challenging part of the telescope development, that means, the manufacturing and the testing of the X-ray mirrors. XMM-Newton consists in 3 Mirror Assemblies (MA). Each MA contains a Mirror Module (MM) including 58 X-ray Wolter I type mirrors named Mirror Shell (MS) and an X-ray baffle (XRB) to reduce straylight. Two of the three MA are equipped with a Reflection Grating Assembly (RGA) for spectral analysis. During four intensive years, more than one thousand MSs have been produced at Media Lario (ML) and several hundreds tested at the Centre Spatial de Liege (CSL). At the end of 1998, three months ahead of schedule, the three flight and the two spare models of the X-ray telescope were handed over to the Spacecraft Prime Contractor, Daimler Chrysler Aerospace. The first part of this paper presents the manufacturing and control process of the individual Mirror Shells and of the full Mirror Modules. It gives also an overview of how the progress has been realised between the first Mirror Shell and the last ones. All the MAs have been tested in the CSL facility. The aim of the tests was to space qualify all the MAs and to check the quality of all the optical subsystems. This was performed in a dedicated facility between 96-98. The second part of the paper explains the need of qualification and environmental test, the method used and the major results.