International Space Station Bipropellant Plume Contamination Model update for short thruster pulse widths

The International Space Station (ISS) Bipropellant Plume Contamination Model
has been a vital tool for characterizing the thruster plume-induced contamination environment
at the ISS but was not intended to be used for very short thruster pulse widths. This paper
presents an updated model that ensures full start-up and shut-down phases are modeled for each
thruster firing, when the majority of liquid phase contaminant mass is released. The updated
ISS Bipropellant Plume Contamination Model prevents potential under-prediction of thruster
plume-induced contamination due to visiting vehicle proximity operations and provides a way to
take advantage of thruster start-up and shut-down performance data gathered during thruster
test programs, if available.