Spacecraft charging: incoming and outgoing electrons

TL;DR

This paper reviews how incoming and outgoing electrons influence spacecraft surface charging, emphasizing the importance of surface conditions and the potential hazards caused by differential charging.

Contribution

It provides an overview of electron roles in spacecraft charging and highlights the impact of surface conditions on surface potential and charging hazards.

Findings

Surface conditions significantly affect outgoing electron currents.

Surface potential is influenced by the balance of incoming and outgoing currents.

Differential charging poses space hazards due to surface condition differences.

Abstract

This paper presents an overview of the roles played by incoming and outgoing electrons in spacecraft surface and stresses the importance of surface conditions for spacecraft charging. The balance between the incoming electron current from the ambient plasma and the outgoing currents of secondary electrons, backscattered electrons, and photoelectrons from the surfaces determines the surface potential. Since surface conditions significantly affect the outgoing currents, the critical temperature and the surface potential are also significantly affected. As a corollary, high level differential charging of adjacent surfaces with very different surface conditions is a space hazard.