Conference attendees were treated to tours of the Centre Spatial de Liège (CSL) and the Advanced Mechanical and Optical Systems (AMOS) at the University of Liege . We began the night with a tour of CSL. A researcher who was part of CSL’s entrance in the Aerospace Industry in the 1960’s described their first mission where they sent a sounding rocket up into the Northern Lights. They are now considered the premiere test facility in the region and their facilities are frequently used by groups such as NASA and the ESA. The director of the CSL then took the time to describe their facilities, how the company has progressed, and some notable missions. We split into two groups to take a tour of their clean rooms (which are 10k, like ours, but can be cleaned to 100). They have a massive vertical vacuum chamber and a wall of heap filters (which, when in use, change the cleanliness from 10K to 100). They also had several shaker tables at their disposal.
At AMOS we were treated to an introductory presentation from the CEO. He discussed the primary industries they work for (Astronomy and Space), mirror technology, and various projects they have done since 1984. We were then split into three groups, and told about various experiments that AMOS is currently conducting and how the industry has changed in the past 10-12 years. Following these information sessions, we were taken to see their mirror manufacturing and polishing facilities. One of their chief technicians explained their manufacturing process and their use of ZERODUR®, aluminium, and silicon carbide. When they test mirrors, they use interferometry with a spherical wave source. This means that spherical based mirrors are easy to work with, while aspherical and non-standard mirror shapes are problematic as fringing effects can occur. To compensate for this, they generate a hologram in the path of the specimen to create a mimicked spherical mirror. Then, when the light interacts with the hologram, it returns the ideal spherical mirror image (thus minimizing the fringing effects). The measurements are taken by examining the distortion of the light waves that interact with both the hologram and the aspherical test specimen.
Finally, we were taken to a manufacturing bay to see the large telescopes that AMOS is working on. One of them was four meters in diameter and was mounted on a very intricate structure. It is meant for a solar observatory being built in Hawaii, commissioned by the National Solar Observatory. This telescope requires special considerations, such as thermal control. For example, the mirror is mounted on hundreds of pneumatic and hydraulic actuators in order to keep the mirror stable and undistorted. The mirror can also be rotated past 90 degrees without falling due to the electromagnet interface.