The Nikkei reports that the Japanese government will soon issue a public solicitation for firms to participate in a project to develop technologies for a space solar power system that would beam electricity generated by orbital solar panels and converted into microwaves in space down to the earth.
The hope is to commercialize orbital solar power by 2030. Such a system would have such advantages as generating electricity regardless of the weather on the ground.
The project will develop technologies to transmit power down to the earth. The idea is to convert solar electricity into microwaves, which would then be converted back into electricity at the surface. The team will first attempt to transmit microwaves for a distance of around 10m; the hope is to extend this to 100m within three to five years.
The Japan Aerospace Exploration Agency (JAXA) has been conducting studies on both microwave- and laser-based Space Solar Power Systems (SSPS) for years, organizing a special committee and working groups. In case of microwave based SSPS (M-SSPS), the solar energy must be converted to electricity and then converted to a microwave beam. The on-ground rectifying antenna would collect the microwave beam and convert it to electricity to connect to commercial power grids.
In the laser-based SSPS (L-SSPS), a solar condenser equipped with lenses or mirrors and laser-generator would be put into orbit. A laser beam would be sent to Earth-based hydrogen generating device.
JAXA has proposed a four-step roadmap ending with commercial SSPS around 2030:
- Tens of kW-class space technology demonstration satellite to demonstrate microwave or laser power transmission. This satellite will be launched in a low earth orbit by the H-IIA class rocket.
- Demonstrate robotic assembly of 10-MW class large scale flexible structure in space on ISS co-orbit.
- Build a prototype SSPS in GEO.
- Build commercial GW class SSPS in GEO.