What are the key design considerations for spacecraft power system architecture?

Power system architecture includes: Generation - Solar arrays (sized for end-of-life power at worst sun angle), RTGs for deep space; Storage - Batteries (sized for eclipse energy and peak loads); Regulation - Direct energy transfer (DET) or peak power tracking (PPT); Distribution - Bus voltage selection (28V heritage, 100V+ for high power), harness design; and Loads - Essential vs non-essential categorization, load shedding hierarchy. Design considerations: Power margin (typically 10-20%), Redundancy for reliability, Fault tolerance (fuse/circuit breaker protection), Efficiency (minimize losses in conversion), and Mass/volume optimization. Analysis includes: Solar array degradation, Battery depth-of-discharge limits, Eclipse duration variation, and Thermal effects on efficiency. Power positive validation ensures generation exceeds consumption across mission scenarios.