High Performance Hybrid Upper Stage Motor

Hybrid rocket propulsion is a tipping point technology in the sense that a small, short term investment could have game changing consequences in developing green, safe, affordable and high performance systems needed in future space missions. In order to demonstrate the advantages of hybrids most effectively, the effort should be concentrated on improving the Technology Readiness Level (TRL) of the technology for a carefully selected class of missions. Arguably upper stage motors used in small launch vehicles constitute a perfect platform for this purpose due their relatively small scale and high performance requirements. The advanced hybrid rockets that are being developed by SPG are believed to have the capability to deliver high performances desirable for upper stages, while retaining the cost, environmental and simplicity advantages of the classical hybrids. In order to demonstrate the performance capabilities of advanced hybrid rockets, a design study has been conducted to replace the Orion 38 solid rocket motor with a LOX/paraffin-based system. The LOX hybrids delivering the same level of total impulse as Orion 38 system are determined to be 15-18% lighter. It has been shown that switching to higher performance hybrid upper stages could lead to payload increases up to 40% for a typical launch vehicle. The additional cost, environmental, safety, stop/restart/throttling advantages are expected to make the hybrids desirable alternatives to the existing upper stage systems.