Smart co-phasing system for segmented mirror telescopes

One of the main challenges in space observations is to observe always fainter and more compact objects. This can be achieved by increasing the telescope diameters. So, increasing the primary mirror diameters of the telescopes is the challenge solution but it is technically impossible to manufacture monolithic mirrors larger than 10m in diameter. The use of segmented mirrors thus becomes mandatory. This paper describes the results of a light co-phasing setup mounted in laboratory. This setup is able to correct a piston from 200μm to 15 nm based on coarse (200μm to 300nm) and fine (300nm to 15nm) measurement methods. Both measurements are then chained in a feedback system in order to completely co-phase and keep the segments aligned.