Optical design, performance, and tolerancing of next-generation airborne imaging spectrometers

We describe the optical design and performance of the Next-Generation airborne Imaging Spectrometer (NGIS) currently being constructed at Caltech's Jet Propulsion Laboratory. The new, high-resolution instrument incorporates a number of design advantages including a two-mirror anastigmatic telescope for simplified alignment and high throughput, as well as a concentric, multi-blazed grating for tailored broadband efficiency. A detailed tolerancing and sensitivity approach reveals tight requirements that must be satisfied for spectral calibration and boresight stability. This improved spectral and pointing stability, combined with high uniformity and high signal-to-noise ratio allows us to generate spectrometry measurements capable of answering challenging science questions.