Solar Orbiter is a solar observation satellite launched by the European Space Agency from Cape Canaveral in 2020. Among the many complex instruments it carries, two imaging telescopes operating in the extreme ultraviolet (wavelengths of 17 nm and 30 nm) are designed to study the solar corona. The mirrors used are high-precision optics, on which a stack of reflective layers are deposited to select the wavelengths to be observed.
Franck Delmotte, a teacher-researcher at the Charles Fabry Laboratory, heads the team that designed and manufactured these mirrors. He explains the challenges of this international project and the various stages in the mirror manufacturing process, from the polishing of the optical surfaces to the deposition of the reflective layers by magnetron sputtering.