Abstract The accelerating expansion of space exploration, from satellite mega‐constellations to planned lunar and Martian settlements, demands revolutionary advances in spacecraft power systems capable of operating autonomously for decades under extreme environmental conditions. This review examines the convergence of photovoltaic (PV) and rechargeable battery technologies for space applications, addressing the critical gap between terrestrial research and space‐specific requirements. This work analyzes how extreme stressors in space environments, including high‐energy radiation, thermal cycling, and micrometeorite impacts, drive fundamental innovations in both energy generation and storage. The discussion traces the evolution from conventional silicon and III‐V solar cells to emerging metal halide perovskites, which demonstrate exceptional radiation tolerance and specific power, alongside the transition from nickel‐based to lithium‐ion and solid‐state battery systems. Particular emphasis is placed on integrated architectures, including structural batteries and photo‐rechargeable systems, which blur traditional boundaries between components to achieve unprecedented mass efficiency. Recent advances in tandem solar cells, all‐solid‐state batteries, and machine learning, enabled power management systems that promise to support next‐generation missions, are critically evaluated. Finally, key technological challenges are identified and development pathways for space‐qualified power systems are proposed. These insights establish design principles for power systems enabling humanity's expansion beyond Earth, from satellite swarms to permanent lunar installations.