Using a high index of refraction material such as Germanium (n=4) to diffract light in an infrared spectrometer results in a smaller beam than that required using reflective gratings with air or vacuum (n=1) as the diffraction medium. The resulting instrument is thus much smaller and lighter. For R=50,000 at 3 microns, the beam can be <1 inch. A Ge IG used in the envisioned spacecraft can also use a passively-cooled detector that operates out to 10 microns. We propose to employ this optical element in a compact infrared spectrometer that could use light from a variety of future space-based telescope missions. Our approach leverages capabilities currently assembled at, and aligned with ARC. Deliverables: A grating and test reports that support a SAT ROSES proposal.