Design of a High Reliability Compact CubeSat Propulsion System

A compact (1 liter) propulsion system for CubeSats was designed, incorporating a reliable low hazardous system with high performance. While several propulsion systems are available for CubeSats, the choices are largely between very low specific impulse cold-gas systems and electric propulsion systems with low overall reliability, or a lack of suitability for a secondary payload launch. In this research, a propulsion system with the following characteristics was developed and manufactured: 1) No single-point failures, 2) No hazardous propellants, 3) Total volume less than 1 U (10 cm x 10 cm x 10 cm), 4) Total mass less than 1.5 kg, and 5) No exotic power requirements. The system designed was a resistojet thermo-electric system, using water as a propellant gas, and R-236fa as a low pressure pressurant. This design has the ability to actively control feed pressure for throttle control, and uses four propellant valves arranged by two parallel sets in series with each other, to ensure that if one valve fails either open or closed, there will be neither uncontrolled thrust nor an inability to command thrust. The system was designed primarily with COTS and additively manufactured components, to ensure ease of manufacturability.