The Research Trend on Space-Based Solar Power (SBSP) System

This paper provides a comprehensive review of the latest technological trends and key demonstration projects in space-based solar power (SBSP) systems. As SBSP has re-emerged as a candidate to fundamentally address the intermittency of terrestrial renewable energy, the research paradigm in recent years has shifted rapidly from conceptual studies to hardware-based on-orbit demonstrations. The paper introduces the core components of SBSP systems—(1) high-efficiency, lightweight photovoltaics (PV); (2) ultra-large deployable structures; and (3) wireless power transmission (WPT) technologies—and analyzes major demonstrations that have advanced technology readiness, drawing on academic literature and government reports (e.g., NASA, JAXA, ESA). It covers recent achievements such as Caltech’s Space Solar Power Demonstrator-1 (SSPD-1; assessment of lightweight baseline [ALBA], deployable on-orbit ultralight composite experiment [DOLCE], microwave array for power-transfer low-orbit experiment [MAPLE]) on-orbit mission; JAXA/Japan Space Systems (JSS)’s aircraft-based microwave power transmission (MPT) demonstrations; and NTT/MHI’s laser power transmission (LPT) efficiency records. Finally, it examines ongoing discussions on critical gateways to commercialization, focusing on international frequency allocation (ITU WRC-27/31) and space environmental regulation (ESA’s “Zero Debris” policy).