State-of-the-art in cryogenic solid propulsion research

Cryogenic solid propulsion is a novel type of chemical rocket propulsion, which is based on the idea thai any chemical rocket propellent combination can be used in solid rocket propellant motors, if the definition of solids is not restricted to "solid and stable at ambient temperature". The CSP concept includes all suitable high energy propeilant combinations or additives and stands for sub-cooled, "green" high energy solid propulsion. CSP combines the simplicity of solids with high performance of liquid propulsion. During previous activities it was shown that green propellant combinations using hydrogen peroxide or oxygen along with hydrocarbon polymers are the best choice for entering CSP technology development. The paper describes the status of CSP development as part of a contract with the European Space Agency for larger scale CSP feasibility demonstration within the frame of ESA's Technology Research Program. For this purpose, a dedicated CSP test motor (AI-X1), c apable of holding 1 kg of propellants based on solid hydrogen peroxide and polyethylene, was designed and manufactured at AI: Aerospace Institute (AI) in Berlin. In the course of several hot firings of AI-X1, the general feasibility of multilayer internal hybrid combustion of 1 kg of CSP propellants was successfully demonstrated by AI and its subcontractors Fraunhofer ICT, Schöyer Consultancy and EADS.