An Inefficient, Dangerous System
I read your article [“Successful Test Boosts Hopes for Space Solar Power,” Sept. 15, page 14] about transmitting solar power using radio waves, and there are some characteristics of doing this you should be aware of.
Radio waves undergo serious loss when they are transmitted through air. Humidity in the air can bend the beam causing it to go off target. You can partially compensate for the loss by using a large receiving antenna. The power received is directly proportional to the size of the antenna, but this gain pales miserably when compared to the path loss that varies inversely as the square of the distance. The amount of bend, and more importantly the direction of the bend, can’t be predicted and will change suddenly as a function of time and humidity.
In addition, transmitting through clouds will attenuate the beam further, to say nothing about rain, which could render the system totally inoperative for some period of time.
Then we also must ask what would happen if the system in space were hit with a meteorite and knocked off center by 30 degrees. Does one of our cities get fried before we can shut it down?
A large solar panel such as the one contemplated for this also would be affected by the solar wind, which will attempt to move it or turn it depending on solar conditions.
The system described in your article is hopelessly inefficient, never mind dangerous.