Korea Joins Global Race for Space-Based Solar Power

Space-based solar power is gaining significant attention after Tesla CEO Elon Musk announced plans to build artificial intelligence data centers in space powered by solar energy.

Solar panels in space can generate electricity around the clock with efficiency up to 10 times higher than ground-based systems. This has intensified research and commercialization efforts worldwide.

Japan to Launch 'Ohisama' Satellite This Year

Japan is pursuing space solar development through public-private cooperation. According to Asahi Shimbun, the Japan Space Systems, a nonprofit organization under the Ministry of Economy, Trade and Industry, plans to launch a demonstration satellite as early as this year.

The satellite is named Ohisama, meaning "sun" in Japanese. The system would deploy solar panels spanning approximately 2.5 kilometers in radius at an altitude of 36,000 kilometers. The generated electricity would be converted to microwaves and transmitted to Earth, where a 4-kilometer-diameter antenna would receive and convert the energy for the power grid.

Japan Space Systems said each antenna could produce up to 1 million kilowatts, enough to supply more than 10% of Tokyo's annual electricity consumption.

The key objective is to verify whether microwaves transmitted from space can be converted to electricity on the ground. In 2023, the California Institute of Technology became the first to successfully transmit electricity to Earth using its Space Solar Power Demonstrator prototype. The Ohisama project focuses on actual ground-based conversion to assess commercial viability.

Musk has stated he aims to operate space data centers within two to three years. If successful, the Ohisama project could demonstrate space solar power's potential ahead of Musk's timeline.

EU, China, UK Accelerate Development; Korea Begins Testing

Multiple countries are advancing space solar power development.

The U.S. Air Force Research Laboratory is finalizing plans to launch Arachne, a space solar demonstration satellite, this year. The European Space Agency announced in 2022 its Solaris satellite program, targeting operations by 2030. The United Kingdom aims to achieve 30 gigawatts of space solar capacity by 2040. China plans to launch a 10-megawatt power satellite by 2035.

Korea has also entered the race. The Korea Aerospace Research Institute began developing space solar power demonstration technology in 2022. In 2023, KARI successfully received enough power to illuminate LED lights from 1.8 kilometers away, marking a key milestone.

Musk has been credited with reviving interest in space solar power, a concept first developed in the 1960s United States. SpaceX reduced rocket launch costs by up to 99%, dramatically lowering expenses for deploying large solar panels into space. Growing global pressure to reduce carbon emissions has also renewed attention to the technology.

Cost Remains Critical Challenge

Beam forming technology, which precisely transmits electricity generated in space to ground receivers, is considered essential for the space solar era. Perovskite-silicon tandem cells, which reduce weight while increasing efficiency, are also crucial. Rectenna technology for converting microwaves back to electricity is equally important.

However, cost estimates vary significantly. NASA reported in January 2024 that space solar power could be 12 to 80 times more expensive than ground-based renewable energy. The agency estimated that more than 70% of space solar costs come from rocket launches.

Industry observers criticized the NASA report as excessively conservative, arguing it failed to account for SpaceX's cost reductions.