Space tourism might begin even before there is a space colony, with the building of an orbiting vacation resort. In 1967, at a conference of the American Astronautical Society, the hotel entrepreneur Barron Hilton (son of Conrad) stated that if space transport costs fell to $5 per pound, he would build a hotel in orbit. Actually, inflation has turned Hilton ‘s $5 per pound into what in today’s dollars would be more like $10. With reasonable provision for baggage and for the food and oxygen to be used by the orbiting tourists, a round-trip ticket then might cost $4,000 or so. This is not much more than twice the cost of a round-trip transatlantic ticket on the Concorde and is similar to the costs charged for many cruises by ship. Since the Cunard Line has successfully sold tickets for their most luxurious round-the-world cruises at up to $97,000, the potential is obvious.

The possibility of a space hotel then rests, as does so much else in space, on the availability of low-cost rockets. The scramjet, discussed in Chapter 5, is an entirely new form of engine, which offers the prospect of an aircraft that will fly to orbit as if it were a fast jet plane. The day will come when vacationers can reserve seats on such a craft on a flight out of Miami to orbit.

What a flight that would be! Using turbojet engines, the plane would fly to open ocean, where the sonic boom of supersonic flight would not be annoying. At Mach 2 the jets would shut down and the scramjets take over. Passengers would not notice much, but they would continue to feel the acceleration as the plane gathered speed. Through their windows they could see the sky turn a deeper, deeper blue. Soon it would shade off into virtual blackness, and the curvature of the Earth would be evident. There would be no vibration, no harshness of ride, but on the cabin bulkhead a digital Machmeter would display the increasing speed: Mach 6, Mach 8 and on up as high as Mach 14.

At that speed, and at 120,000 feet altitude, it would be the turn of the scramjets to shut down. In the rear of the aircraft, rocket engines now would thunder to life. With the hardest part of their job already done, the rockets would soon drive the travelers the rest of the way to orbit. The craft would dock with the orbiting hotel, and the passengers could deplane and seek their staterooms.

In the hotel lounge would be large windows offering excellent views of both Earth and space. With telescopes and cameras, or merely sitting in comfortable chairs, the vacationers could sit enthralled as their planet passed below. Awesome would be the sunrises and sunsets, every ninety minutes, as the Sun spread its waxing and waning light across the world or made incarnadine the lower air. The land would offer a never-constant panorama: now the deep reds and yellows of the Sahara, then the dark green of the Amazon rain forest, and again the cloud-speckled blue of the sea. The Himalayas—those majestic mountains spanning the view, yet which one is the Everest which Hillary and Tenzing struggled to climb? The astonishing crystal greens of shallow tropical seas near Bermuda, near the islands of the Pacific. An anvil-shaped thunderhead towering above an expanse of white cloud over Kansas. The great cities of America and Asia, glowing with light amid the nighttime darkness. The feathery watershed of a great river in spring. And always, on the horizon, the light blue where the sky is as seen from below.

When they turn away from their Earth-watching, the tourists will find a number of unique attractions. Since artificial gravity can be set to any level simply by controlling the rotation rate, many Earthside sports and games will take on an entirely new character. For instance, there could be a circular jogging track, on which people could run in the direction opposite to that in which the track is spinning. As a jogger would speed up, his weight would go down, since he would be counteracting some of the centrifugal force that was holding him down. If his pace was fast enough, his weight would vanish entirely, and he might find himself kicking vigorously while slowing rising into midair.

Nor would humans be the only ones to enjoy this; dogs could too. Fans of greyhound racing could find much to cheer in an orbiting version of Hialeah, where reduced gravity would greatly lengthen the graceful strides of the competitors. In fact, an entire orbiting menagerie might develop. What about the idea of turtle races? Think what they could do without the weight of their heavy shells. How would kangaroos fare, or monkeys swinging from the branches of trees? Or a new version of Mark Twain’s “celebrated jumping frog of Calaveras County “? [Author’s footnote: Every July there is a jumping frog competition in Calaveras County, California. The winning jumps have been around twenty-one feet.]

Water sports would take on an entirely new character. A low-gravity swimming pool would resemble an enormous slowly rotating barrel with water all along the inside of its periphery. Someone swimming there could look up and wave to his friends directly overhead, for he would see the water arching uphill to left and right, then continuing overhead to form the interior of the barrel. Swimming with the aid of flippers need not be limited to the water. A swimmer could launch himself upward from underneath, break the surface like a dolphin, and then continue upward into the air. The flippers then could serve as little wings, further propelling and steering the swimmer as he sought to reach the center of the barrel. Ordinarily he would not succeed, and would slowly lose speed, then fall back. But a few would achieve zero-g. There they could float and relax, watching the scene around them.

Human-powered flight could be a most novel and pleasurable sport if the orbiting resort grows large enough. The aircraft would resemble hang gliders, but with a propeller turned by bicycle pedals. The daring aviators could start their flights near the center of a large rotating enclosure, where the artificial gravity or centrifugal force would be weak and the pilots could get a good start. Thereafter, the challenge would be, “how low can you go.” By swooping low, outward from the center, the artificial gravity would increase, and pilots would need more and more effort to maintain the margin of power for a return to the central, low-gravity regions. Of course there would be no danger if someone dipped too low; he would simply glide to a landing on the inside of the enclosure. Still, this would prove quite embarrassing on occasion, especially to someone who wanted to show off.

Even with less elaborate wings, tourists will find opportunities to take advantage of zero-g so as to fly after the fashion of birds. Many vacationers will practice for hours or days till they understand how to control their flight, and thereafter will treasure the home movies or Polaroid photos that will attest to their skill. Yet there will be those for whom these memories will be far from the strongest. Some will seek activities of a very private nature, which may leave them little time for the views from the lounge or for sports.

Among the most popular attractions will be the opportunity for sex in zero-g. Here will be the chance for lovers to try out all the positions that proved uncomfortable or difficult back home, even in a waterbed. The Hindu love manual, the Kama Sutra, will doubtless be popular reading; with good reason, it will be on sale in the airport departure area. Some Kama Sutra experts like to try out difficult positions in the water first, but they will find that space is much better.

Neither partner can be on top or on the bottom when there is no up or down. It will take a lot of cooperation for novice couples to stay locked together, and this will prove easier with the aid of an elastic support. This will be a situation unimagined in the Middle Ages, when the lady of a knight wore a chastity belt; what will be needed here is an unchastity belt, to keep the couple coupled. It may be of pink latex or nylon, with holes for four legs, somewhat resembling a set of underpants to be worn by a baby elephant. However, it will be worn by a rather different animal, what Shakespeare referred to as the beast with two backs.

More experienced couples will dispense with such artifices and rely on the woman to wrap her legs around her man, then to move her body in appropriate ways. A man may prove quite inventive, grappling his woman’s thighs with his knees so as to thrust into her. Others will find various ways for a woman to sit astride her man, facing either forward or backward. And so the long night will pass.

And how good it will be, after the loving, to fall asleep still holding each other in one another’s arms, with no gravity to press the weight of one heavily on the other, or to cut off circulation in arms that would embrace.

As time goes by, there will be many couples who will make love in this way, and many thousands of people who will sample these pleasures of life in space. In the meantime, the space colony will be developing and its people building their powersats. There will naturally be the question of bringing to the colony the pleasures and amenities of such an orbiting resort. With an imaginative colony leadership, they could be the basis for the next phase of colony growth.

As the program for building powersats expands, the need for new colonies will expand apace, and a solid understanding of how to provide for a space community will develop. There will be a large corporation in space, or perhaps several such corporations, which may actually be departments of Earthside governments. These corporations will run the space transport and the centers for space construction. In addition, their orbiting “Panama Canal Zone” colonies will provide homes for the people who live in space; and the corporate management will have reduced to standard practice the means for supplying these people with their needs, without recourse to large-scale transport from Earth. When a new space community is to be built or a section of agricultural land expanded, the board of directors can vote to have these things done under fixed-cost contract. It will be the same as the routine, standard way an airline orders new jet planes.

We may imagine that the corporation that produces and leases the powersats operates a very profitable business on a steady, even financial keel. It has ample flow of cash, and a secure, constant
income from its powersat operations. It is then that the corporation would seek to grow and expand by moving into related areas of endeavor. One alternative would be the real estate business.

There is no reason why real estate development in space should be all that different from its more traditional Earthside counterpart. On Earth, areas of land acquire value when people want them and are willing to bid for them, as at an auction. In space colonies, real estate will have the intrinsic value associated with the capital costs and the energy needed to produce it, but there can be as much of it as one wishes. Land in space colonies will be like autos or refrigerators, which are sold at fixed prices and produced to meet the demand.

The simplest act of space colonization would call for no new construction at all. It would simply involve a change of policy: Instead of the corporation owning the people’s homes and renting them to its employees, the tenants would be granted the opportunity to acquire ownership and a clear title. For those who had been living in space the longest, their rent payments of past decades might simply be counted for bookkeeping purposes as mortgage payments; they could own their homes free and clear. Even the most recent newcomers could have their rental contracts converted into mortgages, and rental payments of past years could be counted as mortgage payments.

Even so simple a change would mark the end of an era. No more would the space-dwellers be regarded as wards of an all-powerful government. No more would there be a central administration to take responsibility for all phases of the people’s lives. It would mark the end of space communities as company towns, as extensions of bureaucratic fiefdoms. It would mark the beginning of a true space economy, aimed not at serving the needs of Earth but rather at serving the people who live in space.

The end of universal government ownership would also mean the end of the policy of tight control over who could and could not live in space. No more would there be careful selection of applicants to fill those jobs and only those jobs that the government deemed worth providing. No more would an employee have to leave the colony if he quit his job or was fired. Instead, there would be opportunities for people to make a living by private employment, providing new goods or services. An Earthsider, long attracted to space, could arrange to buy the home of a retiring space colonist and move there. With a loan from the Bank of the Colony, such a newcomer could work to set up his business, hoping his fortunes would prosper. Home remodelers, builders, general contractors would all find themselves newly welcome in space.

There would be need for caution here. A too-rapid changeover to private ownership could spark a speculative real estate boom. One can well imagine that the mid-twenty-first century will see numerous millionaire space enthusiasts who have whetted their appetites with visits to the space hotel but whose real wish is to live there permanently. In a few days or weeks they might bid the prices of space homes up into the millions as they competed for the few thousand or so newly available properties. Many a colonist would find himself rich overnight, at least on paper, as his modest $50,000 home or condominium happened to catch the fancy of some wealthy Earthsider. By selling, he would realize a quick financial killing; but the space activities would be deprived of his skills as he left for Earth with his money. In the span of a few months the space colony could change its character completely, from a home for valued employees to a center for frenzied real estate speculation. The eventual bursting of this financial bubble then would prove most unpleasant to all concerned.

So it would be important that from the start there be an adequate supply of real estate in space colonies. This would mean building more such colonies, whose land and homesites would be made available to Earthside buyers. There would be other land, too, for light industry and for shopping malls. The day of the company store or commissary would be at an end.

As a minimum, such “for-sale” colonies would be built as a pressure shell of strong metal, with mirrors and window areas to let in sunlight. They would have coverings of lunar soil for radiation shielding, interior atmospheres, more soil on the inside. They would also have equipment for circulating electricity, air, and water while keeping the latter two fit for human use. The interior layouts of such colonies would vary. For those intended as farmland, there would be little more than flat soil. At the other extreme luxurious colonies for those with expensive tastes (and wallets) would offer lakes and streams, marinas, golf courses, elaborate recreational areas, and even equestrian trails. Most likely the land would be sold in a condition ready for development, but without pre-existing buildings or other structures. It would be the responsibility of the buyers, whether as private individuals or commercial firms, to hire contractors to put up their homes and businesses. The colony government would still have its hand in this, but it no longer would be an all-controlling power. Instead, it would be like a real estate developer who seeks to encourage buyers who will contribute to the growth of the community.

Apart from the glamour of living in space and being a part of humanity’s reach outward, there would be an eminently practical reason for Earthsiders (especially those from Chicago or the Northeast) to prefer life in a space colony. A colony could easily be made to have the best climate available, milder than Hawaii or Southern California, entirely free from storms or other surprises, never ceasing to be warm or bright. The weather, of course, would be fully controlled. Nor need the scenery appear unnatural, artificial. If demand booms, it will be quite possible to build colonies that are miles in extent, with a blue sky and clouds, and with room for a million or more. If so few as a
million Earthsiders were to take out mortgages averaging $100,000—the price of a home and lot today in many desirable parts of Southern California—that would be $100 billion. That would provide for quite a bit of space construction.

In 1975, the artist Don Davis prepared a set of color paintings showing visions of the interiors of the largest possible space colonies. He showed parklands and green forests, rivers and hilly uplands, even a bay full of small boats and spanned by a large suspension bridge. Such ideas may appear as mere fantasy, but they are no such thing. They will be entirely necessary if space colonies are to build a reputation for quality and desirability.

Large space colonies may be miles in extent. (Courtesy Don Davis).

Perhaps the activity most resembling this kind of space colonization today is the building of new communities in the deserts of the Southwest. Several such developments have been built by a subsidiary of McCulloch Oil Corporation, which like our fictional powersat firm, is a successful energy corporation that has diversified into real estate. The subsidiary, McCulloch Properties, has built such towns as Lake Havasu City and Fountain Hills, Arizona; Spring Creek, Nevada; and Silver Lakes, California. Over the wasted deserts where twenty-mule teams once hauled borax from Death Valley, there now rise these attractive and much-sought new communities. Lake Havasu City is particularly well known; it is there that McCulloch rebuilt London Bridge, having shipped it from England. It is enough to make one wonder; surely the Golden Gate Bridge cannot forever meet the needs of San Francisco. Will it one day be dismantled and rebuilt in a future Lake Havasu City?

If a space community follows the pattern of the McCulloch developments, its amenities will be lavish indeed. For starters, there will be lakes well stocked with trout and coho salmon. Around the lakes will be boat docks and launching ramps, sandy beaches, barbecue pits, and grassy park areas. Many families will enjoy access to the lakes from their own backyards. Because the landscaping can be in whatever way the developers want, it will be easy to design a lakefront community as a number of long, low, sandy peninsulas extending into the lake. Each peninsula will be wide enough for a road down its length, with lots on either side backing against the water. The sight of brightly colored sailing craft, or of catamarans with aluminum hulls, will be just part of the local scenery.

There will be plenty for the sports-minded. It will not be hard to bring in championship tennis and golf pros, to manage these sports activities, and to arrange special events or tournaments. A professionally designed and landscaped series of golf courses will permit 9-, 18-, or 27-hole play, regular or championship. The ready control over landscaping will mean a challenging layout for every shot. For those who are not so proficient, a large putting green and driving range will permit people to sharpen their game. The game of golf will actually be more challenging in a space colony because the gravity will be artificial. Since it will be provided by rotating the colony, there will be an effect due to the rotation known as the Coriolis force. It will cause golf balls to slice to left or right even if hit straight down the fairway, and even the most proficient of golfers will virtually have to relearn the game to correct for this.

Every golf course must have a clubhouse, and this one will be no exception. Perhaps it will be a two-story structure on a rise of land, with excellent views of the colony interior. There will be a cocktail lounge and an excellent restaurant, a main lounge with high cathedral ceiling and lavish floor space, a fully equipped recreation room with gymnasium facilities, locker rooms, bowling, saunas and massage rooms, whirlpool baths, as well as meeting rooms and movie theaters. Just outside the clubhouse will be the basketball and handball courts, as well as the tennis, and the swimming pools. An Olympic pool with three levels of diving, a Jacuzzi, a small pool for children, all with wide concrete decks and ample beach chairs, with a snack bar, will complete everyone’s enjoyment.

Elsewhere will be a hotel with convention facilities, riding trails and stables for horses, and bicycle paths. These may be in a separate equestrian park. And all these facilities can be provided with no users’ fees charged to the community residents or to their guests.

When building on a lot, the homeowner will have a choice of architectural designs, which permit easy construction with the aid of robots. A builder may control a team of robots as though he were pharaoh driving a gang of slaves in a Cecil B. DeMille movie. This method will likely mean one of a couple dozen standard home layouts, available in different colors or styles of exterior trim, built from factory-manufactured modules. Custom-built homes will cost more. Construction will be straightforward and building codes simple, for there will be no storms or ice, no natural hazards, not even groundwater to leak through a foundation.

Yet if these colonies are to prosper, it will not be enough to establish them as resorts or real estate developments. Their success will call for much more than wealthy or independent space buffs buying homes there for reason of their novelty. Indeed, it would prove a very bad mistake to promote space colonies simply for reasons of fashion, for fashions change all too quickly. Biarritz may have been tres chic last year, but this year no one would be caught dead there, dahling.

Fortunately, there appear to be at least two industries that can supply the economic underpinnings for these orbiting cities. One of these would be the design and building of spacecraft. The powersat will be only the first of these. Just as the settlers of New England took advantage of their forests to develop Boston and New Bedford as important centers for shipbuilding, the space colonies will be advantageously placed to build their own ships.

By developing skills as instrument makers, propulsion specialists, electronics designers, the space colonies increasingly will be able to compete with the Earthside centers for spacecraft development. Among the people who will go there to live may be many astronomers, and other scientists as well. Great observatories and physics laboratories can grow there to take advantage of the vacuum of space and the unimpeded views of the stars.

The second major industry would be information. In the next century many people will spend much of their working days at computer consoles or telecommunications terminals and will be free to live anywhere they please. The use of communications satellites will allow them to do their work and keep in touch with colleagues and associates without having to leave their offices. If such people are attracted to life in the space colonies, it may be less for the golf courses or even the zero-g sex as for the superb, unequaled communications facilities they may command. Consultants, writers, analysts,
financial managers—these may be only a few of the people, many of them self-employed, who will be able to make their livings in the space communities.

These communities can help facilitate the classic dream of astronauts setting off for distant planets on missions of exploration. This is a dream inspired by the historic voyages of Columbus, Drake, Hudson, Cook. It expresses the hope that as the ship with sails set was the very symbol of the Age of Discovery, so might the rocket, outward bound, serve as the harbinger of a new Renaissance.

The present era and the decades ahead are proving indeed to be a great age of space exploration, but the explorers are instruments and robots, not men. The people will follow in their wake, but initially there will be little of the grand romance of an H.M.S. Endeavour or Golden Hinde. Space exploration has much more in common with exploring the Antarctic than with the voyages of Columbus, and one does not venture to Antarctica in crude wooden caravels manned by illiterate sailors from the docks of Cadiz. But for good scientific or economic reasons, we will place large parties in McMurdo Sound or Prudhoe Bay. The same will be true when we send groups of people into the space beyond the Moon.

It was oil, ten billion barrels of it, which brought people to Prudhoe Bay. The space activities of the future will not seek this resource, but they will rely on what to them will be as valuable: water, carbon, nitrogen. With these it will be possible to go beyond the building of structures merely of metal and silicon. There will be new structural materials, stronger and with superior properties. There will be the opportunity for space agriculture. Above all, a ready source of these prizes will point toward the end of dependence upon Earth for a space project’s most vital needs. It will become possible to think in terms of a civilization in space.

The nearest source of water could well be the Moon. For nearly twenty years there has been a solid scientific basis for speculating that water may exist there. The Apollo missions found the Moon to be exceedingly dry, so much so that by comparison the harshest deserts of Earth would appear a rank and growth-choked swamp. Not only was there no evidence of water or ice; the rocks lacked telltale chemical signs of even having ever been exposed to water.

However, all lunar explorations to date have been carried out near the lunar equator, in regions which for billions of years have felt the blasting heat of the Sun. In 1961, a young Caltech scientist named Bruce Murray pointed out that near the lunar north and south poles are permanently shadowed regions where the Sun never shines. An example would be the interior of the crater Peary, whose high rocky walls block all direct sunlight. In such shadowlands there is only the feeble light of sunshine reflected from distant uplands. Nor are the shadow areas small in extent; they cover some one-half of a percent of the total lunar surface, which is about the size of the state of Michigan.

It was the proposal of Murray and two colleagues that these shadowlands could serve as “cold traps.” Temperatures there would always be hundreds of degrees below zero. Any water on the Moon would freeze out and be trapped there. Over geologic eons, sizable quantities of water might accumulate—tens of billions of tons, according to the most recent estimates. This same Bruce Murray in 1976 became director of NASA’s Jet Propulsion Laboratory, the leading center for lunar and planetary exploration. It is not surprising that he has advocated a mission known as Lunar Polar Orbiter, a lunar satellite which would pass over both poles. It would carry an instrument known as a gamma-ray spectrometer, which would detect water in the cold traps, if it exists.

Much of this presumed lunar water would have been brought in by impacts of meteorites or comets. A common class of meteoroids is a type known as carbonaceous chondrites; these typically
have a water content of 3 percent. Much larger quantities of water are known to exist in comets; a single comet could readily have brought a billion tons of water to the Moon.

While lunar water is a matter for speculation, the water content of comets and meteoroids has been measured by observation. As an oil geologist would say, lunar water falls under “possible resources,” but water from comets and meteoroids would be “proved resources.” It thus is quite significant that recent advances in astronomy have made it possible to identify the sources of meteoroids and to find bodies in space that actually are immense carbonaceous chondrites. Moreover, it now appears that a rich source of materials lies close to Earth’s orbit, in many cases scarcely more difficult to reach than the Moon. This resource would not only provide water, but carbon and its compounds (as the description “carbonaceous” attests) and quite probably nitrogen.

These are the Apollo and Amor asteroids. Most asteroids are small rocky bodies orbiting the Sun between Mars and Jupiter, but a few venture closer in. One of them, named Icarus, passes closer to the Sun than the planet Mercury. Those that cross the orbit of Earth are called Apollo asteroids; those that pass just outside Earth’s orbit are the Amor asteroids. Some twenty-eight Apollos have been discovered, and more are being found at the rate of at least four per year. Various astronomers have estimated their total number, and the estimates tend to agree: There are some five hundred to one thousand such bodies larger than a kilometer in diameter. [Author’s footnote: The name has nothing to do with the Apollo program. The first such “Earthcrossing asteroid” was discovered in 1932 and named Apollo; it gave its name to the group.]

In 1937 one such body (Hermes) passed within a half-million miles of Earth, a very near-miss on the cosmic scale. Had it hit, it would have struck with the energy of ten thousand large hydrogen bombs, blasting a crater some twenty miles in diameter. Indeed, such impacts occur three or four times each million years. Most of them are in the ocean, but land impacts are far from unknown. Arizona’s Meteor Crater is an example; a much larger one is the forty-five-mile-wide Lake Manicouagan in northeastern Quebec. Other old impact scars are the Ries Kessel in Germany, the Vredefort Ring in South Africa, and Gosses Bluff in Australia. Canada has an especially well-preserved region of old impact craters. The scars have been preserved in the deep granite of the Canadian Shield and have been uncovered by the action of glaciers. A map of such impacts, prepared by Canadian geologists, makes their country look like nothing so much as a portion of the planet Mars.

These impacts show that there must be a continuing supply of new Apollo asteroids; the existing several hundred would all hit Earth (or Venus) in the course of a few hundred million years. They are, in fact, ancient comets.

Comets come from outside the Solar System, from a region of interstellar space known as the Oort Cloud. A passing star can disturb the motion of some of them, causing them to enter the Solar System. As they pass by Jupiter or Saturn they may be “captured, ” pulled by gravity so as to become a permanent part of the Solar System. A very few experience close encounters with the gravity fields of Mars or Earth. Then their orbits can change so that they become Apollo asteroids.

Just this type of process seems to be taking place with an object known as Comet Encke. Its orbit is intermediate between that of an ordinary comet and that of an Apollo asteroid. What’s more, in recent decades it has shown definite signs of weakening in activity. A comet’s brilliant display results from its content of easily vaporized gases. These gases are frozen in the cold of interstellar space but vaporize when a comet nears the Sun. When they are all gone, a comet ceases to be active and becomes instead a type of asteroid. When Comet Encke becomes inactive, after perhaps a hundred more orbits, it will be an Apollo asteroid and may one day strike Earth. It is unsettling to realize that events in interstellar space could lead to a catastrophe that might wipe out the New York metropolitan area.

Can asteroids be retrieved, transported to Earth orbit to be mined for their valuable water and carbon? In 1964 Dandridge Cole and D.W. Cox wrote a prophetic book, Islands in Space. They proposed that asteroids be used as resource mines, hollowed out or otherwise processed in order to build space colonies. Indeed, they freely used the terms “space colonies” and “space colonization.” Their preferred transport technique was the mass-driver. As a means for launching lunar payloads, the mass-driver was already old; it had been proposed by Arthur C. Clarke about 1950. What Cole and Cox proposed was that it serve as a new type of rocket, or reaction engine. Fitted to an asteroid, it would eject chunks of matter taken from the asteroid itself. The asteroid thus would slowly be consumed as it would wend its way earthward.

Much valuable material would be lost this way, so it is fortunate that there is another way to proceed. This method would use large banks of ion-electric thrusters, such as will move powersats from their construction sites to geosynchronous orbit. An asteroid could be fitted with a chemical plant that would extract oxygen from the minerals in which it is chemically bound. The oxygen, and only the oxygen, would serve to run the reaction engines. The valuable hydrogen and carbon compounds, as well as refined metals, would be saved and not ejected.

Because ion-electric engines give superior performance, this approach would offer several advantages. Much less asteroidal material would be lost as rocket exhaust. The exhaust itself would be a gas, not a hazardous stream of pellets or slugs of rock. That material which is ejected would be the most common of space resources, oxygen. Best of all, the asteroid would be chemically processed into valuable goods even while it was flying en route to Earth’s vicinity.

In an era of concern over resource limits, it is comforting to know that the potential of the Apollos and Amors is not small. If these are regarded as fisheries whose stock is continually replenished, then on the average there are 400,000 tons of new Apollo/Amor asteroids introduced per year. If the Apollos/Amors are seen as a resource to be mined, they could supply a million tons per year for something like ten million years. It should be a long time before there is an Apollo/Amor shortage.

With the tapping of resources from the asteroids, the last requirement will be met for a long-term growth of the space colonies or communities. When these communities are built and settled, the human presence in space will be well on the way to expanding beyond the early beachheads won by the builders of power satellites. Yet in a sense this phenomenon will not be new, but something quite old.
The first settlers in Virginia came to grow tobacco to send to the mother country; how much of the production of today’s America finds its way to England? San Francisco was founded as a seaport, a center for shipping; yet today in the Bay Area one of the most important industries is electronics, and many people there have never set foot on a ship.

The space communities will grow for the same reason other civilizations have grown. They will have abundant sunlight and solar energy, rich resources from the Moon and asteroids, talented and creative minds to seek new opportunities. Like pioneers settling a fertile and well-watered valley, the settlers in space will be able to see the fruits of their efforts. Here will be no outcasts, sent to work a stony soil and to wrest a living from unfavorable lands. Here instead will be youthful, energetic people, confident in the assurance that their efforts will prosper.

The space immigrants will come from many nations. When the colonization of space is thrown open to all, there will be no restriction as to nationalities. It will once again be the opening of the American West, with diverse peoples coming to win a new land. Even at the early stages of the enterprise, there will be need for a colony government. As the population grows, and as the space economy becomes more and more self-sufficient, the human presence in space will become less and less that of a colony, a mere appendage of the mother planet. Increasingly the space-dwellers’ government will assert itself in the councils of the world, speak for its own interests. Slowly, gradually, the space colony will evolve into a nation.

It will be a new type of nation. The newly arrived residents will not be like settlers on the western frontier; rather, they will be like homeowners moving into a new suburban subdivision. Nor will residence in space long remain a matter of golf courses and sports facilities. As with new communities in the desert, these amenities will give the space enterprise a reputation for quality, but there will then be the opportunity to construct much less lavishly appointed developments offering lower price tags to buyers. And this too will not be new. The first autos were expensive, affordable only by the wealthy, but they provided manufacturers with the experience which soon allowed Henry Ford to sell the Model T to Everyman. Airline tickets were for many years quite costly, but once the airlines had grown sufficiently, they were able to offer discount fares for all.

It is in this fashion that the human presence in space will grow. Yet that will not be the end of the story, but merely a new beginning. The influence on human thought will be profound. As the prospects of America embodied all the hope and optimism of nineteenth-century thought, so may the new and vastly larger frontier create new hope in the next century.

The people of space will not be demigods, nor will they be sybarites and hedonists. Rather, theirs will be no more than the strengths and weaknesses of any other people. Their material prosperity will be remarkable, but in the long run they may be cherished more for the hope they will give humanity: The hope of new horizons, of new opportunities, of a better life in a new land. All this will be real, it will be possible, it will exist—it will be theirs.

And the frontier will stretch ever outward. Inevitably, the colonists’ thoughts will be drawn to the stars. The space-dwellers will not be left in ease and luxury, for to them will fall the great but unaddressed human challenge. It will be they who will grapple with the unanswered question: In the vast Milky Way galaxy, in the cosmos of which it is a part, what is the significance of man?

This is the challenge of the stars, and this is the question that will lie before them.