ABSTRACT
Salient aspects of spacecraft charging without beam emission have been given. This chapter introduces beam emissions. For beam emissions, the beam current is included in the current balance equation. As the beam takes electrons away from a spacecraft, the spacecraft potential responds to the beam emission. One common method for measuring spacecraft potential is to use booms. It is assumed that the tip of the boom is outside the sheath potential of the spacecraft body. The spacecraft potential is governed by the balance of currents. Since the beam current is artificially controlled from the ground, one can vary it methodically, observe the spacecraft potential in response, perform the data analysis of the results obtained, and provide meaningful physical interpretations. Ion beam emission for spacecraft propulsion has been of interest for decades. Ion beam emissions from a spacecraft take away ions from it, resulting in charging of the spacecraft.
