Flight Works is proposing to expand its work in micro-gear-pumps for hypergolic and ?green? propellants in order to develop and demonstrate a micropump for MON-25 and mono methyl hydrazine (MMH) bipropellant thrusters. MON-25, with 25% of nitric oxide (NO) and 75% nitrogen tetroxide (NTO, N2O4), allows lowering the oxidizer freezing point to -55 C, which is a close match to that of the fuel, MMH (which is around -51 C). While toxic, this propellant combination is hypergolic and allows operations over a wide range of temperatures, particularly in extremely cold environments as those envisioned for many future missions. For NASA deep space and Moon/Mars missions, such as lunar lander and Mars ascent vehicles, the introduction of a micropump in the propulsion system provides significant performance benefits. For missions with high delta-Vs, the system wet mass is greatly reduced, or at fixed total wet mass, scientific payload mass increases. For example, in the case of a lunar lander (delta-V > 3,000 m/s), a two-stage configuration can be replaced by a pump-fed single-stage system of the same mass while the pressure-fed would have to be larger. Flight Works is proposing to develop and characterize micropumps suitable for 5 lbf and 100 lbf MMH/MON-25 thrusters. These will be used to perform pump-fed MMH/MON-25 hot-fire test demonstrations of the technology under representative environmental conditions in order to reach a TRL 6 by the end of Phase II.
