The idea of getting energy from the Sun has been around for a number of decades. People are familiar with solar power calculators, solar powered traffic lights, and other devices. Ground based solar power has a number of problems, however. The Sun emits untold amounts of energy, a hundred and seven five thousand terawatts (i.e. a 175 thousand trillion watts) of which strike the Earth’s upper atmosphere. Unfortunately much of that energy is reflected back into space, is absorbed by such things as dust and water vapor, or is used to generate photosynthesis in plants. Ground based solar is a very poor technology for powering a modern, industrial society. The surface area of solar cells that would be necessary to run an industrial plant or an office building would be enormous and in most cases unworkable. Fortunately there is another way to tap into the boundless energy of the sun.

The Birth of Space Solar Power

In 1968, Peter Glasser, at Arthur Little, published a paper suggesting that solar collectors placed in geosynchronous orbit around the Earth would be able to collect solar energy and beam that energy down to collectors on the Earth’s surface known as rectennas. In 1974, Glasser discovered and patented a method of transmitting energy from the solar collectors to the ground using microwaves.

Around the same time, NASA became interested in the concept, due in part to the energy crisis then afflicting the world. NASA, either directly or through aerospace contractors, financed studies of space solar power. However, by the early 1980s, when energy prices began to ease, the concept was put on the back burner.

Meanwhile, Gerard K. O’Neil, then a professor of physics, popularized the subject of space solar power in his classic book, The High Frontier. O’Neil’s idea was that space settlements, which he envisioned as being huge, free flying structures where people would live on the inside of cylinders that rotated to provide the semblance of gravity, would become economically viable by building space solar power stations and selling the power to Earth. To make the plan even more viable, these stations would be built out of materials mined on the Moon or from asteroids, thus obviating the expense of lifting building material from the Earth’s surface.

Due to advances in technology and the increase in energy prices, interest in space solar power has revived to a certain degree. The world uses 13 terrawatts of energy per year at the present time. In about fifty years, that amount is estimated to increase to 30 terrawatts. Some people believe that space solar power is one solution to finding that needed energy, without causing pollution.