Conceptual design of a compact space-borne IR high-resolution cross-dispersed spectrograph realized by germanium immersion grating and all-cordierite reflective optical system

We present a new concept of an unprecedentedly compact, 20 cm-sized, IR high-resolution (λ~3μm, R~30,000) cross-dispersed spectrograph employing germanium immersion gratings and an all-cordierite reflective optical system. The spectrograph has high-throughput and can cover an octave of wavelength in a single exposure without mechanisms and electric power, thus it is not only highly efficient but also stable and low power rather than existing IR high-resolution spectrometers for space application. This CubeSat-class spectrograph could expand the opportunity of IR high-resolution remote-sensing spectroscopy to the Jupiter’s and Saturn’s moons for exploring chemical processes of molecules link to life.