Importance of Surface Conditions for Spacecraft Charging
Abstract
This paper studies the importance of secondary and backscattered electrons in spacecraft charging. The secondary and backscattered electron yields from surface materials are affected not only by the energies of the incoming electrons but also by the surface condition. Some typical parameters characterizing the surface condition are the surface smoothness, thickness, surface composition, and surface contamination. By using the published formulae of secondary and backscattered electron yields, the critical temperature values for the onset of spacecraft charging are calculated. The results found are different for different yield formulae. The yields are not only important in governing the current balance at equilibrium and the onset of spacecraft charging, but also in affecting the accuracy of model calculations of the spacecraft potential. This paper suggests that, for predicting spacecraft charging or in spacecraft design, it is inadequate to look up published tables of the yields for a given type of surface material. It is necessary to measure the secondary electron and backscattered electron yields of an actual piece of the surface material, because the thickness, smoothness, surface composition, and so forth can affect the yields and. in turn, spacecraft charging.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 2010
- Accession Number
- ADA529084
Entities
People
- Shu T.F. Lai
Organizations
- Air Force Research Laboratory