TOKYO - Japan is moving closer to testing technology designed to generate solar power in space and transmit the electricity wirelessly to Earth, with researchers now conducting final checks on a flight model for an upcoming satellite experiment.
Koji Tanaka, an associate professor at the Japan Aerospace Exploration Agency, said the project seeks to demonstrate the key technologies needed for a future giant solar power station in orbit. Such a system would collect sunlight in space, convert it into electricity and transmit the energy to receiving facilities on the ground.
Tanaka said wireless power transmission could allow electricity to be directed to different locations, provided that each site had the necessary receiving and charging equipment. Unlike conventional solar panels, which remain fixed after installation, a space-based system could potentially switch the destination of its power beam.
The central technological challenge is ensuring that the beam reaches its intended target with extreme precision. Tanaka described the task as comparable to aiming at a target about 3 centimeters wide from a distance of 1 kilometer.
Although he acknowledged the difficulty, Tanaka said continued experimentation could make such precision achievable. He noted that phased-array antenna technology, which electronically controls the direction of radio waves, is already widely researched and has been put into practical use in fields including radar.
Researchers must also determine how conditions in space may affect wireless power transmission. The planned satellite experiment will examine factors such as the influence of ionospheric plasma on the beam.
Tanaka said the project must evaluate both how the space environment affects the system and how the transmission technology could affect its surroundings. Those issues must be thoroughly examined well before any commercial deployment.
The project has advanced to the stage where a flight model has been built and entered final testing ahead of launch, Tanaka said. The satellite experiment is expected to provide important data on beam control, transmission accuracy and environmental effects, bringing Japan a step closer to determining whether large-scale power generation in space can become commercially viable.
Beyond the technical challenges, efforts to realize space-based solar power will also require international rules governing activities in space and substantial funding for development. Japan's ability to compete in the emerging field will depend not only on engineering advances but also on building international cooperation and securing long-term investment.
