Energid Technologies Corp. has been funded by NASA to develop a proxy digital simulation for lunar and planetary rovers. The Intelligent Robotics Group (IRG) at NASA's Ames Research Center, Moffett Field, CA, manages the project. IRG conducts field tests to prepare for lunar and planetary robotic missions, with a field test typically involving 10-20 scientists and controllers, 10-20 operators, and a remote team of 10-20 that travels to a remote location that has terrain matching the needs of the test, usually in a desert. There is an opportunity in replacing this remote hardware and support team with a digital simulation, or proxy, for some studies. Simulation offers cost savings, a reduced burden on engineers, and improved variation of scenarios for study. The new proxy simulation uses a novel architecture for calculating contact among bodies and modeling interactions. It allows each type of interaction to use a different algorithm. Work on the project will be done in Massachusetts, Texas, and Arizona.