Study on the physicalmechanism of a plasma thruster with wide range of thrust

Considerable progress has been made in recent years in the study of the Earth's gravitational field by observing the motion of satellites in low altitude orbits. However, such observations are hampered by the aerodynamic drag caused by the residual atmosphere, which modifies the orbits of these satellites in an unpredictable way. In order to overcome this problem, an on-board propulsion system with wide range of thrust is needed which will exactly balance the drag experienced by the spacecraft while measurements are being made.