Advances in propulsion systems are key to enabling independent deep-space CubeSat missions. Currently available electric propulsion technologies require relatively high power and thereby heavy power generation systems, severely limiting their utility for missions going away from the Sun. The ionic-liquid electrospray is known to have high power efficiency but a relatively short lifetime in its present state, limiting the total impulse available in such systems. This lifetime limit can be overcome by using several stages of thrusters, which are used in sequence to multiply the total system lifetime. In this paper, we present the design details and laboratory testing results for a staging system that is compatible with the CubeSat standard. This system will later be demonstrated in space on the STEP-1 satellite, which could enable an exciting new era of accessible CubeSat exploration around the solar system.
Nomenclature= Effective exhaust velocity of propulsion system, m/s = Hold-down wire diameter, m = Elastic (Young's) modulus, Pa = Stiffness (spring constant), N/m = Hold-down wire length, m 0 = Spacecraft initial wet mass, kg dry = Propulsion system dry mass, kg pay = Spacecraft payload mass, kg P = Electrical power of propulsion system, W = Specific power of electricity generation, W/kg Δ = Velocity increment from propulsion, m/s