PICO-SATELLITE ORBIT AND ATTITUDE CONTROL BY ELECTRIC PROPULSION

The possibility of maintaining a group of pico-satellites in a bounded formation, using very low power electric propulsion, is presented. A model predictive controller is used to develop a simple control scheme that avoids the need for on-line orbit determination. The control law, verified using a high fidelity propagator, is capable of maintaining a group of pico-satellites within a 1500 km region at an average ΔV of 2.5 m/s per month. In order to reduce the power requirements of the attitude and propulsion systems, a combined control is utilized. Attitude accuracy is shown to be better than 0.5 deg. The combined attitude-orbit control and the simplicity of the control law provide important advantage for implementation in a pico-satellite with extremely limited resources.