The optical manufacturing of the Refocusing Mechanism of NIRSpec

摘要

This paper reports some details about the optical technologies used for manufacturing the mirrors of the RefocusingMechanism Assembly (RMA). The RMA is a novel cryogenic mechanism designed by Galileo Avionica for the NearInfrared Spectrograph (NIRSpec), one of the instruments of the James Webb Space Telescope (JWST). The RMAcontains two flat mirrors in Zerodur coated with Protected Silver. Severe constraints for accommodation in theNirspec imposed very lightweighted substrates to the RMA mirrors and required state of art technologies in order toachieve the specified quality and its maintenance at cryogenic temperatures.