How do solar panels work as spacecraft power sources?

Solar panels convert sunlight directly into electricity using photovoltaic cells. Spacecraft typically use: Silicon cells (mature, ~15-18% efficiency), GaAs multi-junction cells (higher efficiency 28-32%, radiation resistant, used for most missions). Power generated depends on: Solar intensity (varies with distance from Sun), Panel area and efficiency, Temperature (efficiency decreases with heat), Incidence angle, and Degradation over time (radiation damage). Solar arrays may be body-mounted or deployable. Tracking mechanisms optimize sun angle. Eclipse periods require battery power. Power management includes maximum power point tracking. Solar arrays sized for end-of-life power requirements accounting for degradation (~2-3% per year in harsh radiation environments).