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Mitsubishi Heavy says ground test validates wireless power transmission for space solar power systems; 10 kW sent 500m by microwave

Mitsubishi Heavy Industries, Ltd. (MHI) successfully conducted ground demonstration testing of “wireless power transmission,” a new technology presently under development to serve as the core technology of space solar power systems (SSPS). (Earlier post.) In the ground demonstration test, 10 kW of power was sent from a transmitting unit by microwave; the reception of power was confirmed at a receiver unit located at a distance of 500 meters (m) away by the illumination of LED lights, using part of power transmitted.

The transmission distance and power load mark new milestones in Japan with respect to length and volume of wireless power transmission. The testing also confirmed the performance of the advanced control system technology used to regulate the direction of the microwave beam so that it does not veer from the targeted receiver unit.

MHI conducted the ground demonstration testing based on an agreement with Japan Space Systems, the incorporated foundation that has been consigned by the Japanese Ministry of Economy, Trade and Industry to carry out the “2012 Solar Power Wireless Transmission Technology Development Project.”


Wireless power transmission technology aims to eliminate the cable connections conventionally necessary for transmitting electricity; the newly successful test results lead the way to applying the technology in numerous terrestrial fields. The achievement of wireless power transmission over long distances will not only facilitate the transmission of power to locations where installation of power cables has been difficult or dangerous, but is also expected to contribute to transmission of power from offshore wind turbines and various other applications in the future. One readily conceivable application is wireless transmission of power to electric vehicles.

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.


  • Takanori Narita, Keiji Suzuki, Mayuki Niitsu, Toshihiro Kamiya, Kenichi Anma, Nobuhiko Fukuda (2011) “The Development of Space Solar Power System TechnologiesMitsubishi Heavy Industries Technical Review Vol. 48 No. 4

  • Narita, T.; Kimura, T.; Anma, K.; Fukuda, N.; Shinohara, N. “Development of high accuracy phase control method for space solar power system,” Microwave Workshop Series on Innovative Wireless Power Transmission: Technologies, Systems, and Applications (IMWS), 2011 IEEE MTT-S International doi: 10.1109/IMWS.2011.5877136



40 years after 34 kW was transmitted 1.5 km at Goldstone.

Welcome to the 1970's, Mitsubishi.


Just don't expose yourself to the beam if you want to avoid cataracts.


The cattle are standing like statues
The cattle are standing like statues
They smell of roast beef every time I ride by
And the hawks and the falcons are dropping like flies

(betcha can't name what that's from)


(modified a bit)


Knew you couldn't.

It's the bridge to "Home on Lagrange", not part of the officially-published version on Oberg's site.


Ultra narrow beams aimed directly (only) at high receiving antenna could save cows and other grounded animals and humans but flying birds and aircraft would have to learn to avoid those energy beams.

Aircraft could be equipped to detect energy beams and fly around them?

Flying across in a fraction of a second would do less damages to birds and aircraft?


E-P's right, I remember them proving this in the 70s. Mitsubishi, what rock have you been hiding under?


I really like my Mitsubishi electric car but this technology is not for and earth application. The problem is diffusion in atmosphere will lead to radiation leakage.

To be viable for power transmission, power will be much higher than communications signals. So even a small 1% leakage will be very polluting, but acceptable for business. I oppose all wireless power that has potential to leak energy at higher levels than existing communications emissions. Many people choose not to live next to high power lines, so that should not be considered an acceptable level.

Maybe in space this has some niche when launch costs become trivial or solar cell manufacturing is done in space.


Rayleigh scattering is proportional to the inverse fourth power of wavelength, and the proposals for powersats have long included real-time correction of wavefront distortions due to ionospheric inhomogeneity to put as much power as possible on the target.


Don't HARP on this.


I'm the wrong gender to be a HAARPie.

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