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James Webb Space Telescope
Near-Infrared Spectrograph (NIRSpec)


The Near-Infrared Spectrograph (NIRSpec) is a near infrared multi-object dispersive spectrograph capable of simultaneously observing more than 100 sources over a field-of-view (FOV) larger than 3' x 3'. The NIRSpec will be the first spectrograph in space that has this capability. Targets in the Field of View are normally selected by opening groups of shutters in a micro-shutter array (MSA) to form multiple apertures. The microshutters are arranged in a waffle-like grid that contains more than 62000 shutters with each cell measuring 100 µm x 200 µm. Sweeping a magnet across the surface of the MSA opens all operable shutters. Individual shutters may then be addressed and closed electronically. NIRSpec is also capable of Fixed-slit and Integral-field spectroscopy and provides medium-resolution spectroscopy over a wavelength range of 1 - 5 µm and lower-resolution spectroscopy from 0.6 - 5 µm.

NIRSpec will address all of the four main JWST science themes, and much more. It will enable large spectroscopic surveys of faint galaxies at high redshift, obtain sensitive spectra of transiting exoplanets and image line emission from protoplanetary disks and protostars. NIRSpec is being built for the European Space Agency (ESA) by the Astrium consortium with Dr. Pierre Ferruit guiding its development as the ESA JWST Project Scientist. Peter Jakobsen, the NIRSpec Instrument PI, retired in December 2011.

Latest News

July 2014
The entire Integrated Science Instrument Module with NIRSpec in it is now being tested under operational conditions in "CV2" (Cryo-Vac Test 2). As of mid-July all the instruments have cooled to their operational temperatures near or below 40 K. ISIM now starts its Comprehensive Performance Test in which all the instruments are tested for functionality. Later tests will emulate the more varied observations expected when NIRSpec is operational. STScI NIRSpec staff will assist in these tests along with the ESA scientists and engineers.

At STScI, NIRSpec staff have been continuing to work on the many aspects of preparing to support science operations. That includes experiments with documentation and user information systems, observation modeling to simulate realistic instrument usage, and working with software developers on planning tools.

May 2014
NIRSpec has been integrated into ISIM, making ISIM now complete. Basic functionality tests under ambient conditions have all been successful. As part of ISIM, NIRSpec will be extensively tested during CV2, which runs from mid-June to mid-September. Later this year, after CV2, new detectors and new MSAs will be installed in NIRSpec, leading up to the final ISIM test, CV3, in 2015.

December 2013 and January 2014
The STScI NIRSpec team held demonstration sessions at STScI and the AAS of our new prototype software for planning complex Multi-Object Spectroscopy observations with the NIRSpec Micro-Shutter Arrays.

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