Extraterrestrial Civilizations - Isaac Asimov [108]
The lunar material is not perfectly adapted to human needs, to be sure. It is low in the volatile elements carbon, nitrogen, and hydrogen, and these are essential to the functioning of the settlement. Fortunately, the Earth is not short of any of these and can well afford to supply the initial quantities. These would be carefully conserved and recycled, of course, so that replacement supplies would be held to a minimum. Eventually, other sources for volatiles would be exploited—passing comets, for instance.
Dangers and difficulties? Of course.
The possibility of a meteor strike exists, but that is not a very great one. The chance would be far less than that of earthquakes or volcanic eruptions on Earth—which occasionally destroy cities.
Energetic solar radiation is dangerous but would not be a problem in a settlement protected by aluminum, glass, and soil. Cosmic-ray particles offer a more serious problem and the outer hull of the settlement would have to be thick enough to absorb the bulk of them.
Then, too, the centrifugal effect of the cylinder spin would not perfectly duplicate Earth’s gravitation. On Earth, the gravitational pull is not perceptibly altered as we rise from the surface. Inside the spinning settlement, however, the centrifugal effect would weaken rapidly as one rose from the inner surface and fall to zero at the axis of rotation of the settlement. We have no way of knowing yet whether such a fluctuating gravitational effect is dangerous to the human body in the long run, but in view of experiences in space so far, we can fairly hope it won’t be.
Why should such settlements be built? Human beings are not likely to undertake a vast construction project merely for the fun of doing it. The Great Wall of China was built to hold off the barbarian hordes. The Pyramids of Egypt were built because the religious beliefs of the time made it seem that preserving the body of the monarch was essential to the well-being of the nation. The medieval cathedrals were built for the greater glory of God.
As to space settlements, the motivation may arise out of our declining supplies of petroleum and the difficulty of finding a source of energy large enough, safe enough, and long lasting enough to replace it.
The direct use of sunlight would seem to be one possible solution and that sunlight can be gathered more efficiently in space than on Earth’s surface. A solar power station can receive the full range of the Sun’s energy, unblocked by atmospheric phenomena. If the station is in Earth’s equatorial plane in synchronous orbit, at a height of a little over 35,000 kilometers (22,000 miles), it will be in the Earth’s shadow only 2 percent of the time over the course of a year.
A number of solar power stations girdling the Earth could solve humanity’s energy needs for the indefinite future and could also give Earth’s nations a positive reason to cooperate, since building and maintaining the stations would serve as literal lifesavers for each of them alike.
If such solar power stations are understood to be needed and if the effort is made to build them, the space settlements will naturally come into being to house the workers who will serve on the mining stations on the Moon and at the construction sites themselves.
Indeed, beginning with the drive for power stations, space may be put to greater and greater use as observatories, laboratories, and whole factories (much more computerized and automated than they are on the Earth’s surface) are lifted into orbit.
With so much of man’s industrial and technological activity lifted into space, Earth may return to a more desirable wilderness/park/farm condition. We could restore the beauty of the Earth without losing the material advantages of industry and high technology.
Once the space settlements are established over the next couple of generations as part of a program for meeting the dire need of Earth’s population for energy, there may be a number of ancillary advantages.
As the space settlements increase in number, the room available for human beings