Cryogenic Optical Testing In Focal 5

The vacuum facility FOCAL 5 (Facilite d' Optique et de Calibration a Liege de 5 metres) is a test facility of the space research centre "IAL Space" of the University of Liege - Belgium. It has been tailored for thermal vacuum testing of medium size payloads and progressively upgraded for cryogenic payloads including 4.6 K (liquid helium temperature) experiments. The first part of this paper presents the current status of the facility with its potential capabilities. The second part will describe the experimental set-up and the results obtained in the case of the cryogenic testing of either the ESA Hipparcos astrometry payload or the ESA ISO infrared telescope subsystems. The various product assurance, quality control and cleanliness aspects are also reviewed.