A Novel AOCS Cold-Gas Micro-Propulsion System Design and Applications to Micro and Nano Satellites

Propulsion systems are required by several space applications, e.g. Formation Flying, when position and attitude control are foreseen and shall be very fine. The system design can present many challenges regarding system mass and performances: a great number of equipments and thrusters may be required and low and variable thrust values could be needed to manage disturbances on orbit. Throttleable thrusters often lead to an increase of complexity and system size, against small-spacecraft constraints. In this chapter a novel micro-propulsion system is proposed, based on MEMS micro-thrusters developed in house by Carlo Gavazzi Space S.p.A. The system design architecture refers to a baseline configuration where each thrust valve commands a torque around an assigned direction. Optimization for two Italian missions (micro and nanosatellite) is analysed. Both applications require high-accuracy attitude control, involving low thrust values (order of 10 mN) and low impulse bits (order of 10–5 Ns). With respect to the first application, a comparison with a reaction-wheel based system in terms of mass and power has been made, showing a power gain of about 5 W against a propellant mass of about 1.5 g for each attitude manoeuvre (200 s each) in LEO orbit.