Controlling the Electric Potential of the Low-Earth Orbit Microsatellite in Ionosphere Observation Via Langmuir Probe

Using a Langmuir probe mounted on a large satellite is a general method to directly measure ionosphere’s plasma characteristics, such as electron temperature and electron density. Microsatellites are also being planned to be used for this task due to their apparent advantages, such as low-cost and short development time. However, the deployment of Langmuir probe on a microsatellite faces with a problem that the satellite’s electric potential fluctuates significantly as the plasma’s currents are fed to a satellite’s conducting surface which is not much larger than that of the probe. This in turn adversely affects the accuracy of the observation results. In this paper, a technique exploiting an electron gun is proposed to stabilize this fluctuation. The technique is tested in a space chamber and the obtained results are shown to demonstrate the effective controlling of the satellite electric potential.