Following the design of the EUROSTAR bipropellant combined propulsion subsystem (CPS), a test program has been undertaken to assess performance to and validate supporting analyses. The program has involved both simulant, cold-flow tests and live, propellant firings using flight standard hardware. The test platform is fully representative of the flight geometry and, in addition to providing a model of in-flight performance, has permitted a full checkout of fill/drain procedures and operations in advance of the flight activities. This test bed has promoted a deep understanding of the performance of bipropellant systems and the constituent key components in addition to enhancing expertise in analytical methods, instrumentation techniques, and propellant handling.