Optical design of the near-infrared spectrograph NIRSpec

The near-infrared spectrograph (NIRSpec) is part of the James Webb Space Telescope (JWST) science mission: NIRSpec is a spectrograph that works in the near infrared spectral region (0.6micron - 5.0micron) and allows the observation of spectral features of the incident star light with different spectral resolution (R=100, R=1000, R=3000). It is designed for spectroscopy of more than 100 objects simultaneously. The optical design of the NIRSpec instrument is characterized by a straight optical system layout: It constitutes of a set of optical modules of similar optical design type with high performance and low module tolerances. The NIRSpec instrument development is a cooperation of the European Space Agency and EADS Astrium Germany GmbH as prime contractor for instrument development, design, and manufacturing.