GEO_EVOLVE, the NASA/JSC orbital debris simulation model for Earth's geosynchronous region, is in the process of being upgraded to version 2.0. The historical period of geosynchronous earth orbit (GEO) growth is mimicked with the addition of a set of updated and expanded launch/breakup files, and two new orbital propagators servicing objects in GEO and geosynchronous transfer orbits (GTO). This results in a GEO_EVOLVE 2.0 generated environment that is comparable with data from the US Space Surveillance Network (SSN) catalog and NASA's CDT (CCD Debris Telescope). The slow precession of the node and argument of perigee of objects near GEO has driven the development of a pair-wise collision probability algorithm for use in the projection phase of GEO_EVOLVE 2.0. This module is still in the preliminary testing phase.