Extraterrestrial Civilizations (32 page)

But where are we to get all the material for the construction of these space settlements? Our groaning planet, sagging under its weight of humanity, with its supply of key resources sputtering and giving out, couldn’t possibly afford to give up the colossal quantities of supplies needed for it all. Millions to hundreds of millions of tons of construction material would be needed for each settlement.

Fortunately we have the Moon, a completely dead world with no native life, however simple, whose “rights” need trouble our sense of ethics.

Lunar material would yield the aluminum, iron, titanium, glass, concrete, and other substances needed for constructing the colony.
Lunar soil would be spread over the interior surface. Not only is all that material present in the Moon in huge quantities, but lifting it off the Moon against that body’s weak gravity would require only 1/20 the effort necessary for lifting it off Earth. All the smelting and other chemical work would be done in space.

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 would increase, too. Within a century, there could conceivably be room for a billion people on space settlements, and within 2 centuries there would be more people in space than on Earth.

This prospect does not obviate the need to lower our birthrate in the long run, for if human beings continue to multiply at their
present rate, the total mass of flesh and blood will equal the total mass of the Universe in 9,000 years or so.

In fact, it does not obviate the need to lower our birthrate right now, for long before we could put that first billion into space, Earth’s population would have increased by 25 billion and that would be disastrous. And yet the presence of space settlements would offer a bit of an escape valve; the birthrate need not drop quite as far with space settlements in existence.

In addition to allowing some space for human numbers, the burgeoning clusters of space settlements will lend additional variety to human cultures. Each settlement might well have its own way of life, and some might be quite a distance off the norm. Each settlement might have its own styles in clothing, music, art, literature, sex, family life, religion, and so on. The options for creativity in general, and for scientific advance in particular, would be unbounded.

There could even be items of life-style unique to the settlements and impossible to duplicate on Earth.

Mountain climbing on the larger settlements would have comforts and pleasures unknown on Earth. As climbers moved higher, the downard pull of the centrifugal effect induced by the settlement’s spin would weaken, and it would be easier to climb still farther. Then, too, the air would grow neither thinner nor colder to any substantial degree.

Finally, in carefully enclosed areas on the mountain tops, where the centrifugal effect is particularly low, people could fly by their own muscle power when they were outfitted with plastic wings on light frames, thanks to the thick air and the small downward pull.

For the purposes of this book, however, the chief value of the space settlements would be this: They would make possible the exploration of the Solar system—not so much for physical reasons, as for psychological ones.

Consider:

To begin with, space flight is an exotic matter to the people of Earth, something that would take them away from the world on which they live, and on which ancestral life has developed over a
period of more than 3 billion years.

Space flight would, on the other hand, be of the very essence of life to the space settlers. Their worlds would have been populated as a result of space flight; and their labors on the Lunar mining stations and at construction sites would involve space flight as a matter of course.

Tourism would also exist among the multiplying settlements.

Because each settlement would have no perceptible intrinsic gravitational pull of its own, and because all are at roughly the same distance from the Sun, the Earth, and the Moon, travel from one to another would take very little energy. It would be something like coasting on level ice.

Considering the low cost in energy and the fact that various settlements might be each considerably different in culture from others, visitors would have much to be amused by and interested in. It would be quite possible that all space settlers would be space travelers from an early age and the concept would have no terror for them.

Even if the settlers wanted to leave the libration points, or even if they were on the Moon and wanted to leave that world, there would be no need for the strong initial acceleration blast that is required to lift a rocket through the Earth’s atmosphere against the Earth’s large gravitational pull. That instantly removes the most uncomfortable part of space travel.

Therefore, where Earth people might, on the whole, hesitate to venture into space, and where only a tiny fraction would qualify physically and temperamentally as space explorers, the entire population of the space settlements might be potential explorers.

Then, too, the conditions of space flight represent an extreme changeabout to Earth people. Earth people are accustomed to clinging to the outer surface of a very large world; to a cycling of food, air, and water through so vast a system that one is scarcely aware of it; and to a gravitational intensity that is constant wherever they go.

For space settlers, however, spaceflight introduces changes that are not at all extreme. The settlers live on the inside of a world to begin with; they are aware of and accustomed to a close cycling of food, air, and water; they are accustomed to a variable downward pull.

In short, the space settlers, in undertaking an extended space
flight, move from one spaceship to another quite similar, though smaller, spaceship.

All this does not make the space flights to some specific destination necessarily less long or less tedious, but it should enormously lessen the psychological difficulties. A crew of space settlers could undoubtedly endure the restricted quarters of a spaceship over the long flight to Mars and beyond far more stoically and efficiently than a crew of Earth people could.

Again, though, we must ask ourselves for motivation. What would make the space settlers move outward through the Solar system?

Human curiosity and the desire for knowledge might assure the occasional long-distance flight, but something more would be needed for a mass movement.

That something more is easily seen.

The libration points on either side of the Moon are not very large and could easily be filled. Furthermore, as more and more settlements are built and filled, the drain on Earth’s supply of volatile elements would become appreciable and the reluctance of Earth’s people to part with them would become pronounced.

It would be useful to search for additional living space and for a better source of volatiles.

The inner Solar system is, as a whole, poor in volatiles. The Moon and Mercury have none, Venus is unapproachable, and Mars, while approachable and possessing volatiles, may not be an ethical source. By the time the space settlements are ready to move outward, there may be human beings on Martian bases, and the volatiles would, in a way, belong to them.

As I mentioned earlier, comets rich in volatiles wander by now and then, but this is an intermittent and unreliable source and to depend on them would become ever more risky as the number of settlements multiplies.

It is the asteroid belt that is the nearest appropriate target for expanded living space for the settlements. The many thousands of asteroids might offer even more easily attained construction material than the Moon, and many of them should contain considerable quantities of volatile material.

It may well be that by the twenty-second century, the settlements at the libration points will be recognized as a mere preliminary
stage, and it will be the asteroid belt that will be considered the true home of the settlements. They will be farther from Earth and utterly independent of it, but they can remain within radio and television reach of it, of course. There will be endless room out there for the construction of many millions of settlements without crowding.

The outward push might continue even farther and belts of settlements might be placed around Jupiter and Saturn at distances large enough to avoid the magnetic fields and the charged particles with which those are filled.

In short, the space settlers will prove the Phoenicians, the Vikings, and the Polynesians of the Space Age, venturing out on a far vaster sea to settle their new lands and islands.

By the twenty-third century, the Solar system may well have been thoroughly explored by human beings with settlements in favored places throughout. The Sun itself can serve as an adequate energy source if its radiation is properly gathered and focussed, even far out in the vastness of the outer Solar system, and hydrogen fusion reactors should eventually serve as an alternate adequate source.

This optimistic picture of the total exploration and, so to speak, occupation of the Solar system depends, to a surprising extent, on the use of the Moon as a stepping stone.

Suppose the Moon weren’t there in our sky; that it hadn’t been formed along with the Earth by some enormously low-probability accident; or that it hadn’t been captured late in Earth’s life by an equally enormously low-probability accident. Think how that might have affected humanity’s technological development.

It was the Moon that first gave human beings the concept of a plurality of worlds. It was the Moon’s size and nearness that made it an interesting world and lured us out into space toward what was such a tempting target.

Without the Moon, advancing astronomical techniques might have revealed the planets to be worlds, but would human beings have really tried to develop space travel if the nearest reasonable objects were Venus and Mars, and if flights to the nearest reasonable goal would require a round trip of well over a year?

We need an easy target on which to work out the technology of space flight, and human beings have to be encouraged to strive toward that technology with the bribe of an attainable success.

Of course, human beings might still have sent rockets into space and placed people in orbit around the Earth, even without the presence of the Moon. Such flights have many functions other than that of reaching the Moon. The desire to study Earth as a whole—its resources, its atmosphere and weather pattern, its magnetosphere, the dust and cosmic rays outside the atmosphere, the observation of the rest of the Universe from a position outside the atmosphere, the utilization of solar energy—all would have urged us onward to rocketry and space exploration.