Physics-Driven Dual-Defect Model Fits of Voltage Step-Up to Breakdown Data in Spacecraft Polymers

Overly conservative estimates of breakdown strength can increase the mass and cost of spacecraft electrostatic discharge (ESD) mitigation methods. Improved estimates of ESD likelihood in the space environment require better models of ESD distributions. The purpose of this work is to evaluate our previously proposed dual-defect model of voltage step-up-to- breakdown tests with a case study across four dielectric materials. We predicted that materials best fit by mixed Weibull distributions would exhibit better fits with the dual-defect model compared to a mean field single defect theory. Additional data for biaxially oriented polypropylene (BOPP), polyimide (PI or Kapton) from three sources, and polyether ether ketone (PEEK) are compared to the previous study on low-density polyethylene (LDPE). Except in one case, the dual-defect model is a better fit to bimodal distributions of tests results.