Plasma contactor modeling with NASCAP/LEO - Extending laboratory results to space systems

In the laboratory, hollow cathode-based plasma contactors have been observed to both emit and collect ampere-level electron currents with low impedance. The laboratory behavior of hollow cathode-based plasma contactors and the limited space experience with hollow cathodes suggest that, for many applications, a hollow cathode-based plasma contactor is the ideal device to provide electrical connection with the space plasma. In order to confidently extend the laboratory experience to the low-earth-orbit environment, a series of plasma contactor computer models has been developed. Calculations show that a hollow cathode plasma contactor that collects 0.5 A in the laboratory will only collect 2.4 mA in space. The simplest way to boost the collected current is to increase the gas flow. A mole of gas is enough to collect ampere level currents for 5-1/2 hours.