Animation of the light path inside the Near Infrared Spectrometer (NIRSpec) on the Webb Telescope. Showing simulated data.
Credit: European Space Agency
The Near InfraRed Spectrograph (NIRSpec) will operate over a wavelength range of 0.6 to 5 microns. A spectrograph (also sometimes called a spectrometer) is used to disperse light from an object into a spectrum. Analyzing the spectrum of an object can tell us about its physical properties, including temperature, mass, and chemical composition. The atoms and molecules in the object actually imprint lines on its spectrum that uniquely fingerprint each chemical element present and can reveal a wealth of information about physical conditions in the object. Spectroscopy and spectrometry (the sciences of interpreting these lines) are among the sharpest tools in the shed for exploring the cosmos.
Many of the objects that the Webb will study, such as the first galaxies to form after the Big Bang, are so faint, that the Webb's giant mirror must stare at them for hundreds of hours in order to collect enough light to form a spectrum. In order to study thousands of galaxies during its 5 year mission, the NIRSpec is designed to observe 100 objects simultaneously. The NIRSpec will be the first spectrograph in space that has this remarkable multi-object capability. To make it possible, Goddard scientists and engineers had to invent a new technology microshutter system to control how light enters the NIRSpec.