Passive Cathode Coatings and Devices for Spacecraft Charge Mitigation

Physical Sciences Inc. (PSI) and Brookhaven National Lab (BNL) will optimize and scale-up a paintable cathode coating for the prevention of electrostatic discharge (ESD) from spacecraft operating in the low earth orbit (LEO) and geosynchronous orbit (GEO) plasma environments. The passive cathode coating requires no external power, can survive even in low altitude LEO orbits, will have negligible impact on spacecraft size, weight and cost, and is applicable at any point during spacecraft manufacturing. The coatings developed in Phase I achieved discharge current densities of ~18 uA/cm2, 10000 times the minimum requirement, thereby demonstrating the feasibility of the approach. A thin-film device embodying an idealized coating emitted approximately ten times more current. In Phase II PSI and BNL will mature the Phase I coating and device designs through a campaign of systematic component variation. This will lead to optimized coatings and devices, while providing valuable insight into the physical mechanisms at play. PSI will also demonstrate the ability to coat large areas and multiple substrate types using a process suitable for production at the scale required to support deployment and commercialization. In Phase III, PSI will seek opportunities to test the coating in an operational environment.