N O V E M B E R 1 9 5 8
Discuss this article in the Science & Technology forum of Post & Riposte.
Return to Flashback: Our Place in Space
New rocket techniques and new fuels greatly simplifies space exploration. The
cost of space expeditions is rapidly being lowered. One of my Harvard
Observatory colleagues, Professor Theodore Sterne, recently estimated that a
manned round trip to Venus would cost between 2 and 3 billion dollars, a
fraction of our annual military budget. Furthermore, it is interesting to note that only four years ago the trip would have cost about a thousand time that
figure. So great a reduction in cost, which came mainly from a significant
advance in rocket fuels, is not likely to happen again. Incidentally., the cost
would be only one fiftieth as much if the explorer abandoned the luxury of a
round trip and planned to remain on Venus permanently.
The Pyramids are supposed to represent an investment of perhaps 10 per cent of the gross national product over a period of twenty years. If we wanted to make a similar investment, as Dr. Fred Whipple, my Harvard-Smithsonian colleague, and I have calculated, we could put the Pyramids into orbit. Or, for a figure somewhat less than the annual military budget, we could put the recently moth-balled battleship Wisconsin into orbit.
I do not, of course, recommend such projects. I give the figures to show that we can build and launch space craft and indulge in space research without imperiling our democracy.
It takes vision and courage to put money into basic research, which often represents long-term investment. And yet most of our great industries owe their existence to discoveries in the field of pure science. Radio, television, electrical power, atomic power, electronics, plastics, even automobiles could not exist without basic research. I cannot think of a single major industrial fields which does not have a beginning in contributions from pure science.
The chief ingredient of basic research is imaginations. Imagination and understanding, coupled with curiosity. The scientist knows very well what he is looking for and relies on his ingenuity to find it. Although nature may supply an occasional extra dividend in the form of an entirely unexpected result, most basic research is an orderly progression of study.
And so it has been with investigations of outer space. More than a dozen small telescopes have rocketed momentarily to heights of a hundred miles or so, to collect important data about solar radiation in the far ultraviolet -- energy that is trapped by the upper reaches of the earth's atmosphere. Rockets have also carried probes to measure the density and temperature of gases in the immediate vicinity of the earth. They have given information about the number and distribution of "micrometeorites," fine dust particles in outer space.
Enormous balloons have lifted much more powerful telescopes to altitudes of from sixteen to twenty miles for special studies of the sun and planets. These highs are insignificant compared with those attainable from rockets or satellites, but they are great enough to elevate the equipment above those atmospheric layers where turbulence and air circulation cause the images to tremble or twinkle.
From such airborne telescopes, astronomers hope to obtain clearer views of Mars the sun then from ground-based instruments. Further, the problems of controlling the gondola and pointing the telescope are similar to those we shall later encounter in our satellites. Thus balloon research constitutes a significant step toward our ultimate goal: the telescope in space.
Astronomers are definitely planning such instrumentations. They visualize a satellite whose characteristic spinning and tumbling can be reduced to zero by a system of control jets. A telescope in a static shell would remain pointed in a selected direction until moved by remote radio control. Miniature television systems would relay to earth information about the heavens. In all probability some auxiliary device would store up information for periods of an hour or more, releasing it on signal as the satellite came in and of the vast network of tracking stations sprinkled over the surface of the earth.
ONE of the first studies to be made will be an exploration of the starry sky patterns it appears in the far ultraviolet -- say in the region of the principal radiation of atomic hydrogen, the most abundant atom in the universe. And every different the sky will look, too, in this short-wave energy, which is completely absorbed the my atmospheric layers above fifty miles. Some of the brightest stars in the sky -- especially red ones, like Antares or Betelgeuse -- will be extremely faint. The planets, shining by reflects sunlight, will likewise be almost invisible, because the sun is relatively deficient in this region. In certain regions of the Milky Way, the stars themselves are likely to be lost in the diffuse glow of billowing gas clouds in interstellar space. Although we have a broad idea concerning the revelations of satellite telescopes, the details will enable the scientists to perfect his concepts of the structure of the universe, it origin and evolution.
Ultraviolet, X rays, and infrared radiation, all of the energy now stopped by the earth's atmosphere, will become accessible for study. The mysterious cosmic rays, some produced by the sun in a paroxysm of explosive action and others coming from the depths of space or the distant stars, may disclose to us the secret of their origin. Such knowledge will, in turn, contribute to our understanding of atoms and perhaps enable us to build more effective nuclear power plants.
Scientists have recently found that the sun, the hydrogen atoms of the interstellar space, and various other interstellar objects are sending out radio waves, which provide a new tool for studying the structure of the universe. The largest collector of radio waves build to date is the 250-foot "dish" at Manchester, England. Astronomers visualize much larger dishes, sent aloft in collapsed form in rockets. Once ejected they expand or unfold like a giant Japanese parasol to form a receptor for detection and measurement of radio waves much too long to penetrate the electrifies zones of the earth's upper atmosphere.
Space between the stars is not a complete void. It contains both gas and dust. The quantities are minute, to be sure. We should have to sweep up a volume of space as large as the earth to collect enough matter to fill a small flowerpot. But space itself is so vast that the total amount of dust, in certain directions, is great enough to obscure the most distant stars. Anyone who wished may see how a vast dust cloud splits the summer Milky Way in two.
Our sun continually spouts great jets of hot gas into space. Some of these occasionally penetrate the earth's magnetic umbrella, to procure the aurora borealis and make the compass needle tremble. The more violent impacts of solar gas clouds tend to disrupt long-range radio communications. Recent studies indicate that the sun's outermost layer, the corona, is heated and swollen by the violent explosions near the sun's visible surface. Indeed, the earth and perhaps even Jupiter and Saturn probably lie within the distended solar envelope. Theory indicates that the temperature of the corona, immediately beyond the earth's atmosphere, is about 7000,000 degrees absolute centigrade, 1.2 million degrees Fahrenheit.
It is disturbing, almost frightening, to realize that a mere five hundred miles or so overhead lies region where the temperature approaches a million degrees. Does not this hot region constitute a serious hazard to space flight? Will it not melt and consume any solid object passing through it? A careful study proves that the heating-burning effects of the hot space gas is negligible. So few atoms are present that the total available energy is much less than that from ordinary sunlight. Man himself could enter the medium without fear of being burned. Satellites and interplanetary probes will provide us with important data about radiation, matter and magnetic fields in interplanetary space. And this information, in turn will lead to a better understanding of the interaction of the earth with its space environment.
Our own Explorer satellite has already discovered the existence, near the earth, of a zone of cosmic radiation of far greater intensity than we had expected. Whether or not these rays constitute a serious hazard to space travel depends largely on how thick the layer actually is. Further satellite studies are expected to furnish this information, so that we can judge the possibility of shielding against its lethal effects.
Satellites can be used for study of such solar features as sun spots. I believe these objects to be islands of calm in a story ocean of seething gas. The observations will help us understand solar activity.
Satellites, equipped with TV cameras and transmitters, will look earthward and televise pictures of clouds, storm areas, and atmospheric circulation of the world-wide basis. This program should lead not only to improved weather forecasting but to a better understanding of the whole science of meteorology.
In my opinion the military value of space vehicle has been considerably overestimated. Except for weather reconnaissance, the satellites would be essentially useless as a weapon. People seem to have magnifies the potential menace of a satellite, manned or unmanned. An aviator flying a plane could release a bomb that would fall to earth in a predetermined area and cause great damage. Many persons have therefore imagined that an observer in a satellite could similarly drop a bomb on some spot beneath him. They forget that the bomb is also in orbit and that it would follow along beside the satellite until air resistance or some other force separates them. To make such a bomb return to earth, we should have to supply it with a system of guiding rockets -- used in reverse, of course -- similar to the those that put the satellite into orbit. The problems of launching and guiding from a satellite base would be immeasurably greater than those from a base on earth. The intercontinental ballistic missile is a much simpler answer to any question of attack.
FOR some years to come, man will conduct most of his spatial exploration by proxy, sending robots into space to do his work for him. Most of these devices are simple, designed to perform over and over again some elementary function, like measuring the intensity of a specific kind of radiation, the temperature or density of the environment, or the character of a magnetic field. Ingeniously, they encode the information and store it electronically for release on command or on some schedule.
For exploration of the moon or the surface of some planet, man will require a more versatile type of robot -- one that can move about, handle objects, and make decisions. Even the most advanced computing machines are morons. They perform a limited number of function efficiently and often rapidly. But they are no substitute for a man when it comes to making decisions. Man's mechanical representative on the moon must be a sort of tele-robot, a worker controlled by man himself who sees what the machine sees through his television eyes. A small tank with caterpillar traction will provide mobility. The device will posses mechanical arms and hands that can be controlled by man, 250,000 miles away. Such manipulative appendages are currently used inside atomic power plants where man himself cannot go because of the dangerous radiation. One of these tele-manipulators, which visitors can operate to construct toy block houses, is perhaps the most popular exhibit in the U.S. building of the Brussels World's Fair.
When the space vehicle, decelerated by rockets in reverse, finally lands on the moon, the scientist on earth will push the controls that releases the tele-robot from its shell and initiate its exploring mission. As directed, the robot will move in any chosen direction, rotate its television head to survey the rugged lunar terrain. On command, it will pause to dig a hole, measure the thickness or temperature of the dust layer, pick up a rock and subject it to analysis, and so on. A group of such tele-robots might even assemble complex devices or build a base station that man could employ if he were to land on the moon at some later date.
Robots will continue to operate only if they can be supplied with power, presumably electrical. Even though the demands of a machine are far simpler than those of a man, the problem of a power source is not fully solved. Small batteries operated by sunlight supply energy for radio transmitters in some of the Explorer satellites. More complex solar engines are possible. For a permanent station on the lunar surface, these would be ideal. The Russians have recently announced a pocket-sized atomic power plant for use in a satellite, and it seems reasonable to assume that such an engine would be most economical.
Although the currently planned series of lunar probes will not employ mobile tele-robots, they should give significant information about the moon. The flash of a bomb, exploding on impact, would do more than confirm the arrival of the probe. Analysis of light from the flash would tell us something about the chemical nature of the surface layer, the elements comprising the body of the moon. But let us use TNT or other chemical explosives, not H- or A-bombs, whose detonation, however spectacular, would permanently contaminate the lunar surface with artificial radioactivity.
The behavior of the material blasted out would give us a clue as to the depth and extent of the vast dust layers that some astronomers have postulated to account for the appearance of the moon. Here and there on the lunar surface vast relatively smooth areas have all but obliterated mountain chains and craters, of which only peaks and ruined fragments remain. Most astronomers, including myself, have supposed that extensive lava flows have covered the once rugged terrain. But if the blanketing layer consists of dust, it must be a mile or more in depth. And what a hazard such a layer would constitute for lunar exploration -- a trap, worse than quicksand, into which man and equipment would helplessly sink.
We know that the moon is an airless, waterless world, with extremes of temperature ranging form that of boiling water in its daytime maximum to that of liquid air at nighttime minimum. Some evidence already suggest that these extremes exist in a layer that may be only a fraction of an inch deep. If so, the danger of injury from walking on the superheated or sueprcooled surface may not be serious.
The moon turns on it axis at exactly the same rate it goes around the earth. Hence we see only one side of the moon. A probing rocket, circumnavigating the moon, should presently televise to us a view of the unknown, invisible face. We expect to see the same sort of mountains, craters, and plains as we do on the earthward side. But the details will be of absorbing scientific interest.
By some means we should eventually find a definite answer to the question of the origin of the thousands of craters that pockmark the lunar surface. Astronomers generally believe that collisions of large meteorites -- rocks or even small planets -- formed the craters, as they have occasionally done on the earth's surface. But some of the chains of crater pits must have their origin in a type of volcanism, perhaps in lava flows of matter liquefied by the impact. These and hundreds of other question will be answered when space exploration becomes a reality.
ROBOT probes of Venus and Mars should quickly follow those to the moon. Man needs to know more about the atmosphere and the general character of the surfaces of these planets before venturing there himself. Astronomers are currently arguing about he nature of the silvery clouds that perpetually screen the solid surfaces of Venus from our views. Are they dust or water droplets? If the latter, Venus may be entirely covered with oceans and would be a natural source of soda water.
Photographs of Mars taken through the earth's tremulous atmosphere are never perfectly sharp. However, we have seen and verified the existence of the famous Martian "canals," which are not canals at all in the sense of being artificial water ways. In my opinion they are fertile river valleys in a region that has otherwise reverted to desert. Water is scarce but definitely present. The white button of a polar cap is a region covered thinly with hoar frost rather than heavily laden with ice and snow. The cap completely disappears during the course of a Martian summer.
Photographs taken at different time show changes in color and in the shading that go with the Martian seasons. Although other possible explanations exist, I believe that some form of vegetation is responsible for these effects. Whether Mars has animal life, intelligent or not, will be revealed only by direct exploration. In my opinion the complete absence of radio signals from Mars suggest that any hypothetical inhabitants would be less advanced than we are.
The nearest of the Martian satellites would probably be the best location form which space travelers could view the planet. The problem of return from a small satellite would be much simpler than return from Mars, because the satellite's gravitational pull is negligible.
It will be some time before we can expect to send vehicles out further than Venus or Mars. Jupiter would be most interesting. Ten times bigger that the earth, it is the largest planet in our solar system. Its atmosphere contains such gases as methane and ammonia, at temperatures not very different form that of liquid air.
Saturn has an atmosphere similar in composition. The flattened fringe girdling Saturn consist of small particle so frock. Once wonders whether our earth may not also eventually acquire a ring, just from the debris tossed from space vehicles. If so, let us hope that it will consist of material other than vodka bottle and caviar tins.
The growing demands of space research will require tele-robotas of increasing complicity. Eventually it will prove more economical to send man himself into space, fully supplied with everything necessary for survival: air and means of regenerating air in an enclosure capsule-type food, water, and miscellaneous protective devices. I am in no sense urging a crash program of space exploration. We to proceed in orderly fashion from light to heavy satellites. And the final, exciting step of manned space exploration will be a logical development based on information gained from unmanned flight.
The Department of Defense is already thinking in terms of man in space. Some months ago, in a simulated flight to the moon executed by the air force, a man spent a week sealed in a tin can. The submerged crossing of the polar ice cap by the atomic-powered submarine, the Nautilius, even more realistically represents the problem of manned space flight under actual operating conditions. These experiment have demonstrated that man can overcome the physical discomforts and psychological problems of space fight.
The age of outer space is already upon us. Manned flight to the moon and planets is less than a decade away. And science fiction of space exploration will become much of a reality as has Jules Vernes' famous submarine, the Nautilius. The real question is: Whose program have I just outlined? Ours or the Russians'?
In the fields of missiles and satellites, the United States has clearly fallen behind Soviet Russia. The reason for our inferiority is simple and well known throughout the scientific and industrial world. High official in the Defense Department have opposed pure reassert, especially in the missile and satellite fields. Active antagonism, especially from Secretary of Defense Wilson, stymied the efforts of scientists to develop a progressive program of missiles and space research. No enemy-planned sabotage could have been more effective or more devastating. Arbitrary budget cuts forced cancellation of vital programs and development as well.
The facts speak for themselves. The first successful Russian attempt placed into orbit a 185-pound sphere, in addition to the 50-foot, 3-ton rocket that comprise the third stage. The most recent Sputnik weighs a ton and a half, and the final rocket stage, also in orbit, must weigh at least twice as much. A small wonder that foreigners almost universally sneer at the U.S. miniature satellites, weighing only 3 pounds and having dimensions of the order of a softball. The Russians have a standard joke. "the trouble with American satellites," they declare, "is that no on can find a dog small enough to go up in one."
The Sputniks, in their way, were probably the best thing that could have happened to America. They shocked us out of our complacency and revealed our vulnerability. Basic science began to live again.
Despite the inadequacies of our satellite development, we have reason to be hopeful. The satellite launched by the United States in July weighed 31 pounds, and plans call for early launching of satellites with pay loads between 200 and 500 pounds. These figures indicate substantial progress. The program needs more funds, issued without stifling restrictions. And the support must be given in an atmosphere of intelligent, friendly consideration. There is no reason why the U.S. satellite program should continue to be as inferior as it is today. Space research is vital to our future.
If we are to draw a parallel between space flight and any of man's past achievements, the great exploration of our earth furnish us with a standard of comparison: exploration of the Americas, of the heart of Africa, or of the polar regions. The hardy frontiersmen could not possibly have foreseen the great developments that would follow from their pioneering. Is colonization of Venus, Mars, or even of the moon sheer fancy? Only time will tell.
Meanwhile, the American people should give whole hearted support to a full-scale space program. We can be sure that the scientific discoveries and new inventions made in the course of our effort to attain space flight will more than pay the cost. Success is within our view. Our scientists merely need the respect, confidence, and support of governmental leaders to make the greatest adventure of all history a reality.
Copyright © 1958 by Donald H. Menzel. All rights reserved.
The Atlantic Monthly; November, 1958; The Astronomer's Stake in Outer Space; Volume 202, No. 5; pages 95-99