ABSTRACT Rayner, J.T. 9319039 This project will construct a 0.9-5.5 um medium cross- dispersed spectrograph for use as a facility instrument at the 3-meter NASA Infrared Telescope Facility (IRTF) on Mauna Kea. In conjunction with a fast tip-tilt secondary at the IRTF, the spectrograph will accommodate 0.25-0.30" images at 1-2.5 um and diffraction-limited a spectral resolution of R=1200, through a 0.3"x5" slit. The instrument will use a 512x512 Insb focal plane array. The major innovation in this instrument over existing spectrographs is the capability of observing over the entire near infrared range at high sensitivity and at very high angular resolution, making it an ideal instrument for a number of key astronomical projects. These include spectroscopic surveys of small bodies in the solar system to enhance studies of how our solar system formed, spectroscopic surveys of young stellar objects in the most nearby molecular clouds to probe sites of possible planet formation, spectroscopic surveys of star forming regions to spectrally type young embedded stars to provide new insights into star formation, investigation of galaxy formation and early evolution, and distinguishing starbursts and monsters in powerful infrared galaxies. ***