Japan is making significant strides in the development of space-based solar power, with plans to test a mini solar power plant in low Earth orbit next year. The mission, part of the OHISAMA project (Japanese for Sun), is on track for launch in 2025 and aims to contribute to the global effort in reducing dependence on fossil fuels.
Details of the OHISAMA Project
At the International Conference on Energy from Space held in London last week, Koichi Ijichi, an adviser at the Japanese research institute Japan Space Systems, shared details about the country’s plans. The mini space-based solar power plant will be a small satellite weighing approximately 400 pounds (180 kilograms) and will transmit about 1 kilowatt of power from an altitude of 250 miles (400 kilometers).
While the planned demonstration is not on the scale required for commercial use, it is a significant step forward in the development of space-based solar power technology. One kilowatt of power can run a small household appliance, such as a dishwasher, for around an hour, depending on its size.
How the Space-Based Solar Power Plant Works
The spacecraft will use an onboard 22-square-foot (2 square meters) photovoltaic panel to charge a battery. The energy stored by the battery will then be transformed into microwaves and beamed towards an antenna on Earth. Due to the high speed at which spacecraft travel, approximately 17,400 mph (28,000 km/h), the antennas on Earth will need to be spread over a distance of 25 miles (40 kilometers) and placed at a distance of 3 miles (5 km) from each other to allow for sufficient energy transmission.
The researchers have already successfully demonstrated wireless transmission of solar power on the ground from a stationary source and plan to conduct the transmission from the aircraft in December.
Overcoming Challenges and Harnessing Potential
The concept of space-based solar power generation was first described by Apollo engineer Peter Glaser in 1968. At the time, it was considered science fiction due to the high costs associated with the large installations required in orbit. However, experts at the recent conference shared that recent technological advancements could make this a possibility in the near future.
Space-based solar power plants have the potential to provide a consistent and uninterrupted power supply, as they are not affected by weather conditions and nighttime like Earth-based solar plants. This technology could play a crucial role in combating the growing threat of climate change, which is largely attributed to the use of fossil fuels for energy needs.
Earlier Developments in Space-Based Solar Power
Earlier this year, Caltech announced the successful completion of its Space Solar Power Demonstrator (SSPD-1) mission. The mission tested three new solar power technologies, including wireless power transmission in space, the efficiency of different solar cells, and a lightweight structure to carry and support the solar cells and power transmitters. The success of this mission paves the way for the commercial viability of space-based solar power.
