Japan is making significant strides in the development of space-based solar power, with plans to transmit solar energy from space to Earth by next year. The project, spearheaded by the Japanese research institute Japan Space Systems, aims to demonstrate the feasibility of a miniature space-based solar power plant that could help reduce dependence on fossil fuels and combat climate change.

Koichi Ijichi, an adviser at Japan Space Systems, revealed the roadmap for the project at the International Conference on Energy from Space held in London. He explained that the demonstration will involve a small satellite weighing about 180 kilograms (400 pounds), transmitting approximately 1 kilowatt of power from an altitude of 400 kilometers (250 miles) above Earth.

Although the demonstration is not on the scale required for commercial use, it represents a significant milestone in the development of space-based solar power. The satellite will utilize a 22-square-foot (2 square meters) onboard photovoltaic panel to charge a battery. The accumulated energy will then be converted into microwaves and beamed to a receiving antenna on Earth.

With the spacecraft traveling at a speed of around 17,400 mph (28,000 km/h), the antenna elements will need to be spread over a distance of about 25 miles (40 km), spaced 3 miles (5 km) apart, to ensure sufficient energy transmission. Ijichi noted that the transmission process would only take a few minutes, but recharging the battery after depletion would require several days.

Scheduled for launch in 2025 as part of the OHISAMA (Japanese for "sun") project, Japan's space-based solar power initiative aims to revolutionize the renewable energy sector. The researchers have already successfully demonstrated wireless transmission of solar power from a stationary source on the ground, with plans to conduct a transmission from an aircraft in December.

Space-based solar power generation, initially proposed by former Apollo engineer Peter Glaser in 1968, was once deemed impractical and costly due to the required infrastructure in orbit. However, recent technological advancements and the urgency to decarbonize the global power supply have changed the perception of this concept.

Unlike other renewable energy technologies that are subject to weather conditions and time of day, space-based solar power has the potential to provide a constant energy source. This quality makes it an attractive solution to complement existing power generation methods, such as nuclear or gas and coal-fired power plants.

The experts at the conference highlighted crucial factors, including advancements in robotics, improved wireless power transmission efficiency, and the emergence of SpaceX's Starship rocket, that could contribute to the realization of space-based solar power. The success of the Space Solar Power Demonstrator mission by Caltech engineers last year, which marked the first-ever beaming of solar power from space, has further fueled interest in the technology.

Numerous space and research agencies, including the European Space Agency, the Defense Advanced Research Projects Agency, and the U.S. Air Force, are exploring space-based solar power. Commercial companies and startups are also embracing the concept, leveraging the availability of Starship and advancements in space robotics.

As the world continues to face the challenges of climate change, Japan's progress in space-based solar power brings hope for a greener and more sustainable future.