The advent of powerful Commercial Off The Shelf (COTS) real-time hardware and significant advances in dynamic modeling and simulation software, combined with strides in cost-efficient virtual instrumentation and animation tools, provides the means for development of innovative low cost spacecraft control solutions. In this paper we develop hardware and software system architectures for a flexible simulator which can function as a powerful platform for research, education and testing. The objective is to provide a basic system configuration that is modular and can be easily reconfigured to meet several different requirements, thus providing a single platform for different phases of the design and development process. The use of graphical modeling and automatic code generation tools that are tightly integrated with the hardware ensures rapid software reconfiguration. The paper also discusses two applications that have taken advatage of this architecture.