20mN, Variable Specific Impulse Colloid Thruster, Phase II

Primary NASA applications include missions requiring exceptional thrust/power in power-limited missions, and missions benefiting from variable specific impulse (200-2000+seconds) and variable thrust (10x throttling). In many cases, the proposed colloid thruster may prove superior to most other electric propulsion technologies in nearly all metrics for power levels <200 Watts (where thruster efficiency has greater impact on total system efficiency). The primary non-NASA application for the proposed thruster is to support development of colloid-based multi-mode propulsion using green monopropellants, where there is a lack of suitable thrusters at the milliNewton level or greater. This allows a spacecraft to utilize shared propellant tanks for high thrust chemical propulsion as well as high Isp electric propulsion, and is particularly attractive for small spacecraft with limited mass and volume for multiple propellant tanks. Additional applications include replacement of some of the lower thrust plasma-based electric propulsion devices, which suffer from decreased efficiency at low power due to unfavorable surface-to-volume scaling. The variable Isp capabilities and higher thrust levels provide a useful multimode solution for spacecraft requiring both dwell/stationkeeping as well as rapid maneuvers from a single propulsion system. More »