With the proliferation of small satellites resulting from CubeSat standardization of flight hardware elements, new mission architectures involving automated small satellite proximity operations are increasingly relevant. While small satellite lifecycle costs are often tightly constrained, a rigorous program of requirement verification and validation during flight system integration and testing is needed to ensure successful performance during proximity operations. To meet this need, the proposed investigation will develop a test environment that combines high-fidelity software simulation with a hardware-in-the-loop test bed, for the validation of nano- and micro-satellite missions involving relative proximity operations. This system will provide an environment to test the integrated spacecraft through the entirety of the proximity operations portion of its mission, including the simulation of power production, visual stimuli, and attitude determination and control in response to the test environment. Development of a dedicated software simulation capability coupled with a hardware-in-the loop test bed will provide for a powerful facility aimed at the advancement of autonomous small satellite systems for proximity operations.