The Merits of Cold Gas Micropropulsion in State-of-the-art Space Missions

Cold gas micropropulsion is a sound choice for space missions that require extreme stabilisation, pointing precision or contaminationfree operation. The use of forces in the micronewton range for spacecraft operations has been identified as a mission-critical item in several demanding space systems currently under development. Cold gas micropropulsion systems share merits with traditional cold gas systems in being simple in design, clean, safe, and robust. They do not generate net charge to the spacecraft, and typically operate on low-power. The minute size is suitable not only for inclusion on high-performance nanosatellites but also for high-demanding future space missions of larger sizes. By using differently sized nozzles in parallel systems the dynamic range of a cold gas micropropulsion system can be quite wide (e.g. 0 – 10 mN), while the smallest nozzle pair can deliver thrust of zero to 0.5 or 1 mN using continuously proportional gas flow control systems. The leakage is turned into an advantage enabling the system for continuous drag compensation. In this manner, the propellant mass efficiency can be many times as higher than that in a conventional cold gas propulsion system using ON-OFF-control. The analysis in this work shows that cold gas micropropulsion has emerged as a high-performance propulsion principle for future state-of-the-art space missions. These systems enable spacecraft with extreme demands on stability, cleanliness and precision, without compromising the performance or scientific return of the mission.