Miniature, Axisymmetric Nanolayered Ceramic Composite Liquid Rocket Thruster

Low-cost microspacecraft systems being considered for future development will require a variety of mini- to micro-sized liquid propellant rocket engines for orbit insertion, planetary descent and ascent, reaction control, and precision station-keeping. Currently proposed miniature and micropropulsion devices are prime candidates for the application of ncreased performance requirements gained from energetic, high specific impulse propellant mixtures without the need for active cooling. Recent advances in the development of chemical vapor deposited (CVD) nanolayered composites and fabrication techniques offer promise to increase micro-device performance beyond that achievable with currently proposed materials and fabrication techniques. The objective of this Phase I program is to demonstrate the feasibility of producing miniature, axisymmetric liquid bi-propellant rocket thrusters from nanolayered ceramic composites in an effort to overcome the limitations of existing designs, materials and fabrication techniques. CVD-based SiC is selected as the primary material constituent because of its low thermal expansivity, high thermal conductivity, and outstanding high-temperature mechanical properties and oxidation resistance. Minor nanolayering constituents will be selected for empirical evaluation based on their: (1) known ability to effectively interrupt the SiC deposition epitaxy, thereby increasing strength and thermal shock resistance by controlling grain refinement; and (2) propensity to provide beneficial elastic modulus mismatch, thereby further increasing strength and fracture toughness by limiting dislocation motion. Following the development of a viable composite system, miniature thrusters with integral impinging-stream injectors will be fabricated and delivered to BMDO for further evaluation.