Japan Plans to Beam Solar Power from Space to Earth in 2026
Published · Updated · 3 min read
Japan is preparing to launch a satellite that will collect solar energy in orbit and send it wirelessly to the ground, marking one of the most advanced tests of space-based solar power ever attempted.
The mission, called OHISAMA, meaning “sun” in Japanese, is scheduled for launch later in 2026. The 180-kilogram satellite, roughly the size of a washing machine, will orbit Earth at an altitude of 400 kilometers and transmit approximately one kilowatt of power to receiving stations on the ground.
A Small Output With Big Implications
One kilowatt is enough to run a small appliance for about an hour. But the goal of the mission is not scale. It is proof.
Japan Space Systems, the organization leading the project, designed OHISAMA to show that solar energy collected in space can be reliably converted into microwaves and beamed back to Earth. The satellite carries a two-square-meter photovoltaic panel that will capture sunlight and convert it into microwave radiation for transmission.
The signal will travel down to a receiving station in Suwa, in Nagano Prefecture, central Japan, where 13 antenna arrays spread across a 600-square-meter area will capture the energy and convert it back into usable electricity.
Precision Is the Core Challenge
The hardest part of the mission is not collecting energy. It is directing it accurately.
The microwave beam must stay on target with an angular error of less than 0.001 degrees, while the satellite travels at more than 17,000 miles per hour. Advanced beam-steering electronics will adjust the transmission angle in real time to keep the beam locked on the fixed ground receiver.
Researchers at Kyoto University have spent decades developing this wireless transmission technology. Ground-based tests have already demonstrated the ability to transmit 1.8 kilowatts of microwave power over 55 meters with strong efficiency, giving the team confidence in the space-to-ground approach.
Why Japan Is Pushing This Technology
Japan imports more than 90 percent of its energy, leaving it exposed to price swings and supply disruptions. The 2011 Fukushima nuclear disaster added pressure to find alternatives that are both safe and domestically controlled.
Conventional solar farms are limited by cloud cover, nighttime, and a lack of available land. Space-based solar power addresses all three. Satellites in orbit receive solar radiation around the clock and face no weather interference.
Japan has set a target of net-zero greenhouse gas emissions by 2050, and its government formally included space-based solar power in its national space policy as far back as 2009, as detailed in Japan’s long-planned photovoltaics from space. In 2024, the government established the Space Strategy Fund, committing roughly one trillion yen, or about seven billion dollars, over ten years to support advanced space technology development.
Other Nations Are Also Competing
Japan is not the only country pursuing this technology.
In 2023, researchers at the California Institute of Technology demonstrated wireless power transmission between spacecraft in orbit and detected the energy at receivers on Earth’s surface through its MAPLE project. That milestone proved that lightweight microwave transmitters could survive launch and operate in space.
China has announced plans for kilometer-scale solar arrays in orbit, with a phased timeline running from small demonstrations in the 2020s to gigawatt-scale systems by mid-century. A gigawatt-scale system would match the continuous output of a large nuclear power plant.
A 2024 NASA analysis found that space-based solar power costs remain far above terrestrial renewables today, as outlined in NASA’s 2024 space-based solar power report. But the same report noted that with lower launch costs and continued technology improvements, the gap could close significantly by 2050.
What Comes After OHISAMA
A successful demonstration in 2026 would not immediately lead to a commercial power station. But it would confirm that the core technology works in real orbital conditions, something no mission has fully validated before.
Researchers and government planners see OHISAMA as the foundation for progressively larger systems in the decades ahead. Megawatt-scale demonstrations could follow in the early 2030s, with gigawatt-scale systems potentially viable by mid-century if launch costs continue to fall and materials technology advances.
For now, the world is watching to see if a satellite the size of a washing machine can change the future of energy.
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