Solar energy has bathed the Earth throughout its history. The ancient Greeks had begun to recognize some of its potentials for man. Small machines using solar energy were built and exhibited during the 19th century, but they were mostly curiosities.
Solar energy powered Skylab; it has powered most of the United States spacecraft. Now, in the latter part of the 20th century, its potential value is beginning to be perceived as a limitless, permanent source of energy. Coal, “combustible rock,” was known to antiquity. Its use on a commercial scale began in England during the l6th century. Petroleum was discovered in the 19th century, and petroleum-based liquid fuels soon came into commercial use. During the 20th century, fossil sources of energy have been being depleted a million times faster than their creation rate. As a result, the age of petroleum is ending; but coal will be a principal source of fuel until at least well into the 21st century. Also during the 20th century, developnent has teen initiated on two alternative sources of energy representing “permanent” solutions — nuclear (particularly fusion) and solar. The need for energy to provide power for civilization is so critical that all promising sources should be pursued.

Boeing’s studies of the powersat have resulted in their consensus that the most practical way to use solar energy for electric power on a large scale may well be to collect it in space, without hindrance by darkness and weather. It is believed that the powersat should be considered as a promising long-range energy system and that current technology is sufficiently mature to initiate the beginning steps toward its development.

The time for a decision of major commitment is not now. The decision recommended now is to begin in-depth engineering and economic study of power from space. Many incremental decision points, each dependent on successful accomplishments, will lead to full-scale deployment. The promising long-range potential of the powersat is there; now is the time to take first steps.