The Colonization of Space.
1. The Colonization of Space We have put men on the Moon. Can people live in space? Can permanent communities be built and inhabited off the Earth? Not long ago these questions would have been dismissed as science fiction, as fantasy or, at best as the wishful thinking of men ahead of their times Now they are asked seriously not only out of human curiosity, but also because circumstances of the times stimulate the thought that space colonization offers large potential benefits and hopes to an increasingly enclosed and circumscribed humanity.
Permanent communities can be built and inhabited off the Earth. The following chapters present a detailed description of a system for the colonization of space. It is not the best system that can be devised; nor is it complete. Not all the important questions about how and why to colonize space have been posed. Of those that have, not all have been answered satisfactorily. Nevertheless, the 10-week summer study is the most thorough and comprehensive one made to date. On its basis space colonization appears to be technically feasible, while the obstacles to further expansion of human frontiers in this way are principally philosophical, political, and social rather than technological.
THE OVERALL SYSTEM
The focus of the system is a space habitat where 10,000 people work, raise families, and live out normal human lives. Figure 1-1.shows the wheel-like structure in which they live. This structure orbits the Earth in the same orbit as the Moon in a stable position that is equidistant from both Earth and Moon. This is called the Lagrangian libration point, L5. The habitat consists of a tube 130 m (427 ft) in diametral cross section bent into a wheel 1790 m (over 1 mi) in diameter. The people live in the ring-shaped tube which is connected by six large access routes (spokes) to a central hub where incoming spacecraft dock. These spokes are 15 m (48 ft) in diameter and provide entry and exit to the living and agricultural areas in the tubular region. To simulate Earth's normal gravity the entire habitat rotates at one revolution per minute about the central hub.
Much of the interior of the habitat is illuminated with natural sunshine. The Sun's rays in space are deflected by a large stationary mirror suspended directly over the hub. This mirror is inclined at 45 degrees to the axis of rotation and directs the light onto another set of mirrors which, in turn, reflect it into the interior of the habitat's tube through a set of louvered mirrors designed to admit light to the colony while acting as a baffle to stop cosmic radiation. With the help of abundant natural sunshine and controlled agriculture, the colonists are able to raise enough food for themselves on only 63 ha (156 acres). The large paddle-like structure below the hub is a radiator by which waste heat is carried away from the habitat.
Abundant solar energy and large amounts of matter from the Moon are keys to successfully establishing a community in space. Not only does the sunshine foster agriculture of unusual productivity, but also it provides energy for industries needed by the colony. Using solar energy to generate electricity and to power solar furnaces the colonists refine aluminum, titanium, and silicon from lunar ores shipped inexpensively into space. With these materials they are able to manufacture satellite solar power stations and new colonies. The power stations are placed in orbit around the Earth to which they deliver copious and valuable electrical energy. The economic value of these power stations will go far to justify the existence of the colony and the construction of more colonies.
Principal components of the overall space colonization system and their interrelations are shown schematically in figure 1-2.
DESIGN GOALS
This system is intended to meet a set of specific design goals established to guide the choice of the principal elements of a practicable colony in space. The main goal is to design a permanent community in space that is sufficiently productive to maintain itself, and to exploit actively the environment of space to an extent that permits growth, replication, and the eventual creation of much larger communities. This initial community is to be a first step in an expanding colonization of space.
To effect this main goal, the following subsidiary goals must be met using existing technology and at minimum cost:
Design a habitat to meet all the physiological requirements of a permanent population and to foster a viable social community.
Obtain an adequate supply of raw materials and provide the capability to process them.
Provide an adequate transport system to carry people, raw materials, and items of trade.
Develop commercial activity sufficient to attract capital and to produce goods and services for trade with Earth.
Fortunately, the design study could draw on substantial earlier work. Active interest in space colonization as a practical possibility began in 1969 when Gerard O'Neill and students at Princeton University undertook a detailed assessment of space colonization. They aimed at a model to show the feasibility of a space colony rather than an optimum configuration and they selected as a test case a rotating habitat in satellite orbit around the Earth at the distance of the Moon, using solar energy to sustain a closed ecological system. They proposed a habitat constructed of processed lunar ore delivered by an electromagnetic accelerator and located at either the Lagrangian point L4 or L5 in order to make delivery of the ore as simple as possible. (The Lagrangian points are described in ch. 2.) The habitat was configured as a l-km long cylinder with hemispherical end-caps. It was to have an Earth-like internal environment on the inner surface and be supplied with sunlight reflected from mirrors
(ref. 1).
Subsequently, the Princeton group suggested that the L5 colony could construct solar power stations from lunar material. They concluded that this would improve the economics of both the satellite solar power stations and the colony itself (ref. 2).
The concept of satellite solar power stations has received increasing attention since its introduction by Peter Glaser in 1968 (ref. 3).
These ideas were further considered and developed by a conference "Space Manufacturing Facilities" which took place at Princeton University on May 7-9, 1975 and focused more attention on O'Neill's test case.
This report presents a rationale for the design choices of the Ames-Stanford study group and it details how the various parts of the system interrelate and support each other. The next three chapters discuss successively how the properties of space specify the criteria that a successful design must satisfy, what human needs must be met if people are to live in space, and the characteristics of various alternative components of the design. Some readers may wish to skip directly to chapter 5 where the details of the operation of the system are described. Chapter 6 provides a detailed analysis of the sequence of events needed for the colony to be built. Timetables, manpower requirements, and levels of funding are presented for the construction of the main parts of the overall system. This chapter also looks at long-term benefits from solar power stations in space and some possible ways to structure economics so as to initiate the establishment and growth of many colonies over the long term. Chapter 7 looks at the future development of colonization of space, and finally chapter 8 discusses why space colonization may be desirable and provides some conclusions and recommendations for further activities and research.
THE HISTORY OF AN IDEA
The history of the idea of space colonization extends back into myths and legends of ancient times, but the first account of an actual space colony appeared in 1869 when Edward Everett Hale's novel, Brick Moon, described how a colony in space happened by accident.
brick sphere, intended for guiding maritime navigators, was to be catapulted into Earth orbit by rotating wheels. When it rolled onto the catapult too soon, still containing many workers inside, the first space colony was launched. Fortunately, the workers had ample food and supplies (even a few hens), and they decided to live the good life permanently in space, maintaining contact with the Earth only by a Morse code signalled by making small and large jumps from the external surface of their tiny spherical brick colony (ref. 4).
The following quotation on the history of the idea of space colonization is taken with permission directly from "Space Colonization Now?" by Robert Salkeld, Astronautics and Aeronautics, September,1975.
"Precursors of the notion of small self-contained worlds in space appeared in novels by Jules Verne in 1878 and Kurd Lasswitz in 1897 (refs.5, 6).
"In 1895 the space-station concept was noted from a more technical viewpoint in a science-fiction story by Konstantin Tsiolkovsky (ref. 7). In 1903 Tsiolkovsky expanded his description of the manned space station to include rotation for artificial gravity, use of solar energy, and even a space "greenhouse" with a closed ecological system (ref. 8). Thus, at the turn of the Twentieth Century, the idea of the space habitat was defined in terms of some of its basic elements. The idea progressed slowly over the next fifty years, then accelerated. In 1923 Hermann Oberth elaborated on potential uses of space stations, noting that they
could serve as platforms for scientific research, astronomical observations, and Earth-watch (ref. 9). In 1928 Guido von Pirquet considered a system of three stations, one in a near orbit, one more distant, and a transit station in an intermediate elliptical orbit to link the other two; he suggested that they might serve as refueling depots for deep space flights (ref. 10). The concept of a rotating wheel-shaped station was introduced in 1929 by Potocnik, writing as Hermann Noordung. He called his 30-m-diam station "Wohnrad" (living wheel) (1) and suggested that it be placed in geosynchronous (2) orbit
(ref. l l). During World War II, space stations received some military study in Germany (ref. 12), and after the war the idea surfaced again in technical circles as a geosynchronous rotating-boom concept
(3) proposed by H. E. Ross in 1949 (ref. 13).
"The space-station idea was popularized in the United States by Wernher von Braun. In 1952 he updated Noordung's wheel, increased the diameter to 76 m, and suggested a 1730-km orbit (ref. 14). At about the same time, Arthur C. Clarke published "Islands in the Sky," a novel involving larger stations (ref. 15), and in 1961 Clarke (in another novel) suggested placing large stations at the Lagrangian libration points where they would maintain a fixed position relative to both the Earth and the Moon (ref. 16). In 1956 Darrell Romick advanced a more ambitious proposal for a cylinder I km long and 300 m in diameter with hemispherical end-caps having a 500-m-diam rotating disc at one end to be inhabited by 20,000 people (ref. 17).
"The companion idea of a nuclear-propelled space ark carrying civilization from a dying solar system toward another star for a new beginning was envisioned in 1918 by Robert Goddard. Possibly concerned about professional criticism, he placed his manuscript in a sealed envelope for posterity and it did not see print for over half a century (ref. 18). In 1929 the concepts of artificial planets and self-contained worlds appeared in the works of 1. D. Bernal and Olaf Stapledon, and by 1941 the interstellar ark concept had been fully expanded by Robert A. Heinlein and others, many appearing in the science-fiction publications of Hugo Gernsback and others (refs. 19-24). In 1952 the concept was outlined in
more technical detail by L. R. Shepherd (ref. 25), who envisioned a nuclear-propelled million-ton interstellar colony shaped as an oblate spheroid, which he called a "Noah's Ark."
"A related idea, the use of extraterrestrial resources to manufacture propellants and structure, was suggested by Goddard in 1920. It became a common theme in science fiction and reappeared in technical literature after World War 11. In 1950 A. C. Clarke noted the possibility of mining the Moon and of launching lunar material to space by an electromagnetic accelerator along a track on its surface (ref. 26).
"In 1948 Fritz Zwicky suggested use of extraterrestrial resources to reconstruct the entire universe, beginning with making the planets, satellites, and asteroids habitable by changing them intrinsically and changing their positions relative to the Sun (ref. 27). A scheme to make Venus habitable by injecting colonies of algae to reduce atmospheric CO2 concentration was proposed in 1961 by Carl Sagan (ref. 28). In 1963 Dandridge Cole suggested hollowing out an ellipsoidal asteroid about 30 km long, rotating it about the major axis to simulate gravity, reflecting sunlight inside with mirrors, and creating on the inner shell a pastoral setting as a permanent habitat for a colony (ref. 29).
"In 1960 Freeman Dyson suggested an ultimate result of such planetary engineering (ref. 30); processing the materials of uninhabited planets and satellites to fashion many habitats in heliocentric orbits. A shell-like accumulation of myriads of such habitats in their orbits has been called a Dyson sphere."
On July 20, 1969 Astronauts Neil A. Armstrong and Edwin E. Aldrin, Jr., walked on the Moon. In the context of history just reviewed the ". . . one small step for a man, one giant leap for mankind" appears quite natural and unsurprising. And if the first step is to be followed by others, space colonization may well be those succeeding steps. Perhaps mankind will make the purpose of the next century in space what Hermann Oberth proposed several decades ago:
"To make available for life every place where life is possible. To make inhabitable all worlds as yet uninhabitable, and all life purposeful."