MEMS Mega-pixel Micro-thruster Arrays for Small Satellite Stationkeeping

Small satellites flying in clusters require periodic “stationkeeping” to keep them in place. The required impulse is very small – the goal is not to keep the individual satellites in rigid formation, but only to keep them in well-defined orbitals with respect to one another. The necessary impulse, therefore, is only the amount needed to overcome the difference in drag between the most-affected and the least-affected satellites in the cluster. Estimates are that the differential drag can be overcome by providing ~1 μNsec (micro-Newton second) to ~1 mN sec (milli-Newton second) every 10 to 100 seconds throughout each satellite’s mission. The system we are developing will do that. The thrusters have very low power and energy thresholds for ignition (~10 mWatts, ~100 μJoules), and no moving parts so they are expected to be highly reliable. A single thruster array contains a quarter of a million separate thrusters.