Modular Multirotary Joints SPS Concept—Challenges and Design Considerations

As a major space-based energy infrastructure in response to the challenge of climate change, space solar power (SSP) has attracted extensive international attention for more than 55 years. Recently, various SSP concepts have been proposed, aiming to efficiently harvest gigawatts of solar power over Earth's geostationary orbit and transmit it to the Earth wirelessly. Based on the multirotary joints solar power satellite (MR-SPS) concept proposed in 2014, this article presents an updated modular MR-SPS (MMR-SPS) concept, together with the challenges and design considerations. The primary objective is to address the challenges associated with long-distance dc electric power transmission and exceptionally high-precision microwave power transmission. The MMR-SPS employs multiple modules, each further including a solar subpanel and an antenna subpanel. The solar subpanel and antenna subpanel in each module are connected with each other via conductive rotary joints with a much shorter distance compared with that in the MR-SPS concept. As a result, lower voltage in electric power transmission is allowed, which significantly reduces the complexity of the system and increases its reliability. Retroreflective beamforming is employed to ensure the accurate steering of the microwave power beam to the ground's receiving aperture. For the first time, this article analyzes and validates the performance of using retroreflective beamforming to compensate for antenna position deviations through a numerical calculation model that includes near-field effects. Additionally, this article outlines the transportation and assembly methods, along with the considerations of the full life-cycle cost for an MMR-SPS.