ESA's Herschel telescope is surveying the infrared cosmos with the largest mirror flown in space. This 3.5 m-diameter reflector came from a small French firm whose workers once produced much more compact items: ceramic bearings and seals for industrial pumps.
What is really remarkable about Herschel's mirror is less its large size than its low mass: at just a third the mass of the Hubble Space Telescope's main mirror, it provides twice the observing area. It comes down to a very specific European technology mastered by a single company, working alongside ESA and Herschel prime contractor EADS Astrium...more.