Microshutters, seen here being inspected on June 23, 2012, are a new piece of technology being used on the Near Infrared Spectrograph (NIRSpec) instrument on Webb. NIRSpec is an instrument that will allow scientists to capture the spectra of more than 100 objects at once. Because the objects NIRSpec will be looking at are so far away and so faint, the instrument needs a way to block out the light of nearer bright objects.
The Near-Infrared multi-object Spectrograph disperses the white star light into a spectrum so that the contribution of individual atoms and molecules in the star can be seen. The atoms and molecules in the star imprint lines on this spectrum that uniquely fingerprint each chemical element and reveal a wealth of information about physical conditions in the star. Spectroscopy (the science of interpreting these lines), is among the sharpest tools in the shed for exploring the cosmos.