Coating technology for the World's Biggest Eye On The Sky
The coating plant for the segments of the primary mirror of the Extremely Large Telescope (ELT) in Chile
People have been gazing at the stars since Antiquity. Today, astronomers and physicists are still intrigued by questions of the origin of the universe and the potential for extra-terrestrial life-forms. Recently, astronomers found water in the atmosphere of the exoplanet K2-18b, which is 110 light-years away from earth. K2-18b is in the “Goldilocks” zone, meaning that the distance from its star should allow temperatures which are neither too hot nor too cold for liquid water to exist on its surface. Liquid water is an essential condition for life as we know it.
The Extremely Large Telescope (ELT) is a next-generation space telescope currently under construction in Chile by the European Southern Observatory and is scheduled for first light by 2025. With a primary mirror diameter of 39 meters composed of 798 individual coated mirror segments, the ELT will provide images of K2-18b which are 16 times sharper than those from the Hubble Space Telescope.
The magnetron sputtering technology used to precisely deposit the thin reflective layer on each mirror segment is inspired by coating equipment traditionally used within the glass industry. The equipment is earthquake-resistant and allows the application of coatings with optimal reflection in the visible and infra-red spectra.