Characterization and simulation of the gas pressures in space for high voltage breakdown

The theory of gas flow in the molecular range was used to develop equations that may be used to model the pressures in a space system. It is noted that one key factor associated with the volume electrical breakdown in a vacuum is the residual gas in the vacuum. In a space system it is possible that regions could have pressures that are close to the Paschen minimum. The pressures of evacuated regions are determined mainly by the pressures of connected regions, the conductances to the connected regions, and the outgassing load presented by the materials in the regions. In the molecular flow range, conductances are modeled by C=1.6×10⁵ Aα where A is the area of the orifice connecting two regions and α is the transmission probability of the connection. The outgassing load presented by the materials is modeled by integrating the number of molecules leaving the surface. The pressure change may then be calculated using dP/dt=(-CP+Q)/V . These techniques have been incorporated into a computer model used to predict the pressures in vacuum regions. The results of an application of this model are presented