Mid-infrared Spectroscopy from the Stratosphere: EXES and SOFIA

The Stratospheric Observatory for Infrared Astronomy (SOFIA) will provide a unique opportunity for spectroscopy in the mid-infrared, allowing high spectral and high spatial resolution investigations of molecules that are blocked by the Earth's atmosphere. To take advantage of this opportunity, we are building the Echelon-cross-Echelle Spectrograph (EXES), a PI class spectrograph operating from 5.5 to 28.5 microns. High spectral resolution (R = 100,000) will give optimum sensitivity to cold interstellar gas and provide access to information in spectral line profiles. No current or planned spaceborne instrument will have this capability. In addition to the cross-dispersed high resolution mode, EXES can operate as a long-slit spectrograph at R = 10,000 and R = 3000. These resolving powers can address a broad range of Galactic, extragalactic, and planetary problems. We acknowledge USRA for providing the funds to develop EXES.