James Webb Space Telescope (JWST) mirror assembly. The JWST mirror consists of 18 of these hexagonal mirror segments (each made from beryllium and coated with gold). Each segment is mounted to six actuators that can adjust the segment in 5-nanometre steps. The JWST is an infrared telescope that is scheduled to be launched in 2021. By using infrared wavelengths, the JWST will be able to see through much of the dust that obscures visible light. It will also study dark matter, thought to form the majority of the matter in the universe. Photographed on 9 April 2003, at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama, USA.