In late 2008, the Lunar Reconnaissance Orbiter (LRO) mission will be launched into orbit around Earth's moon.1,2 The LRO mission will conduct exploration-enabling observations. One of the objectives of this mission is to characterize the lunar radiation environment and its biological impacts on humans. For this purpose a collaboration involving research personnel from Boston University, Massachusetts Institute of Technology, The University of Tennessee, The Aerospace Corporation, Air Force Research Laboratory, and the NOAA Space Environment Center successfully proposed to develop a sensor system called the Cosmic Ray Telescope for the Effects of Radiation (CRaTER). CRaTER will directly measure linear energy transfer (LET) spectra, thereby providing a direct link between the ambient environment and its biological impact on future human missions to the Moon. In this presentation an overview of the CRaTER team and project organization will be presented and the current version of the proposed CRaTER instrument will be described. Preliminary computational predictions of some components of the LET spectra will be presented.