CHAPTER 1

THE MEANING OF SPACE SCIENCE

The science managers in the new National Aeronautics and Space Administration of 1958 for the most part had limited experience in the management of science programs. By comparison with the broad program about to unfold, the previous sounding rocket work and even the International Geophysical Year programs were modest indeed. Yet the evolving perceptions of these individuals as to the nature and needs of science would play a major role in the development of the U.S. space science program. At first those perceptions were largely intuitive, growing out of personal needs and experience in scientific research, although a rather extensive literature made the thoughts and experience of others available. In addition, in launching the new program the space science managers had the benefit of the wise counsel of Deputy Administrator Hugh Dryden and Administrator T. Keith Glennan, both of whom had had considerable experience in managing science and technology programs.

Because of the central role played by the concepts of science that NASA managers brought to bear-sometimes consciously, sometimes subconsciously-on the planning and conduct of the NASA space science program, some of those concepts are set forth here at the outset. Moreover, the reader should bear in mind that these concepts are implicit in the author’s treatment of space science in this book. The exposition below, while a substantial elaboration of a summary presented to Congress in the spring of 1966, is still highly condensed, and runs the risk of oversimplification.¹

SCIENCE A PROCESS

A major theme throughout this book is that of science as a worldwide cooperative activity, a process, by which scientists, individually and collectively, seek to derive a commonly accepted explanation of the universe. The author recalls learning in the ninth grade that science was “classified (i.e., organized) knowledge,” only to have to discard that definition years later as the very active nature of science became apparent. To be sure, organized knowledge is one of the valuable products of science, but science is far more than a mere accumulation of facts and figures.

Science defies attempts at simple definition. Many-both professional scientists and others-who have sought to set forth an accurate description of the nature of science have found it necessary to devote entire volumes of elaborate discussion to the subject.² None has found it possible to give in a few sentences a complete and simple definition, although James B. Conant perhaps came close: “Science is an interconnected series of concepts and conceptual schemes that have developed as a result of experimentation and observation and are fruitful of further experimentation and observations.”³

On a casual reading, this definition may again appear to characterize science as a static collection of facts and figures. One must add to the definition the activity of scientists, their continuing exchange of information and ideas, and their penetrating criticism of new ideas, working hypotheses, and theories. A static mental construct alone is insufficient; one must include the process that constantly adds to, elaborates, and modifies the construct. All of this Conant-himself an eminently successful chemist-does actually include in what he is trying to convey in his brief definition, as is patent from the amplification he provides in the rest of his treatment. Indeed, the last clause of the quoted definition, requiring that the concepts and conceptual schemes of science be “fruitful of further experimentation and observations,” clearly implies the ongoing nature of science.

The difficulty of conveying in brief the nature of science, particularly to the layman, has led in exasperation to such statements as, “Science is what scientists do. “The circularity of this definition can be frustrating to one seriously trying to understand the subject-a legislator, for example, endeavoring to appreciate the significance of science for the country and his constituents, and to discern what science needs to keep it healthy and productive. Yet the definition suggests probably the best way of approaching the subject; that is, to tell just what it is that scientists do.

Scientists work together to develop a commonly accepted explanation of the universe. In this process, the scientist uses observation and measurement, imagination, induction, hypothesis, generalization and theory, deduction, test, communication, and mutual criticism in a constant assault on the unknown or poorly understood. Consider briefly each of these activities.

The scientist observes and measures. A fundamental rule of modern science is that its conclusions must be based on what actually happens in the physical world. To determine this the scientist collects experimental data. He makes measurements under the most carefully controlled conditions possible. He insists that the results of experiment and measurement be repeatable and repeated. When possible, he measures the same phenomenon in different ways, to eliminate any possible errors of method.

To experimental and observational results the scientist applies imagination in an effort to discern or induce common elements that may give further insight into what is going on. In this process he may discover relationships that lead him to formulate laws of action or behavior, such as Newton’s law of gravitation or the three fundamental laws of motion, or to make hypotheses, like Avogadro’s hypothesis that under the same pressures and temperatures, equal volumes of different gases contain equal numbers of molecules.^* It is not enough that these laws be expressed in qualitative terms; they must also be expressed in quantitative form so that they may be subjected to further test and measurement.

The scientist generalizes from the measured data and the relationships and laws that he has discerned to develop a theory that can “explain" a collection of what might otherwise appear to be unconnected or unrelated facts. In seeking generalization, the scientist requires that the new theory be broader than existing theory about the subject. If the new theory explains only what is already known and nothing more, it is of very limited value and basically unacceptable.

The new theory must predict by deduction new phenomena and new laws as yet unobserved. These predictions can then serve as guides to new experiments and observations. By taking predictions and working them together with other known facts and accepted ideas, the scientist can often deduce a result that can be put to immediate test either by observation of natural phenomena or by conducting a controlled experiment. Out of all the possible tests, the scientist attempts to choose those of such a clear-cut nature that a negative result would discredit the theory being tested, while a positive result would provide the strongest possible support for the theory.

In this connection, it must be emphasized that the scientist is not seeking “the theory,” the absolute explanation of the phenomena in question. One can never claim to have the ultimate explanation. In testing hypotheses and theories the scientist can definitely eliminate theories as unacceptable when the results of a properly designed experiment contradict in a fundamental way the proposed theory. In the other direction, however, the scientist can do no more than show a theory to be acceptable in the light of currently known facts and accepted concepts. Even a long-accepted theory may be incomplete, having been based on inadequate observations. With the continuing accumulation of new data, that theory may suddenly prove incapable of explaining some newly discovered aspect of nature. Then the old theory must be modified or expanded, or even replaced by an entirely new theory embodying new concepts. Thus, in his efforts to push back the frontiers of knowledge, the scientist is continually attempting to develop an acceptable “best-for-the-time-being" explanation of available data.

In all this process the scientist continually communicates with his colleagues through printed journals, in oral presentations, and in informal discussions, subjecting his results and conclusions to the close scrutiny and criticism of his peers. Ideally, observations and measurements are examined and questioned, and repeated and checked sufficiently to ensure their validity. Theories are compared against known observation and fact, against currently accepted ideas, and against other proposed theories. Acceptable standing in the growing body of scientific knowledge is achieved only through such a searching trial by ordeal.

One should hasten to add that this is not a process of voting on the basis of mere numbers. Even though the majority of the scientific community may be prepared to accept a given theory, a telling argument by a single perceptive individual can remove the theory from competition. Thus, the voting is carried out through a continuing exchange of argument and reasoned analysis. Those who have nothing to offer either pro or con in effect do not vote.

This process or activity called science has developed its rules, its body of tradition, from hard and telling experience. Recognizing that the scientific process cannot yield the absolute in knowledge, scientists have sought to substitute for the unattainable absolute the attainable utmost in objectivity. The scientific tradition wrings out of final results as much as possible of the personal equation by demanding that the individual subject his thoughts and conclusions to the uncompromising scrutiny of his skeptical peers.

The above are things that scientists do, and through the complex interchanges among scientists these activities amalgamate into what is called science. But at this point one must ask what factor distinguishes science from a number of other endeavors. Observation and measurement, imagination, induction, hypothesis, generalization and theory, deduction, test, communication, and mutual criticism are used in various combinations by the economist, the legislator, the social planner, the historian, and others who today in partial imitation of the scientists apply to their tasks and studies their concepts of what the scientific method is. The distinguishing factor is fundamental: underlying the pursuit of science is the basic assumption that, to the questions under investigation, nature has definite answers. Regardless of the philosophical dilemma that one can never be sure of having found the right answers, the answers are assumed to exist, their uniqueness bestowing on science a natural, intrinsic unity and coherence. In contrast one would hardly argue that societal, political, and economic problems have unique answers.

These latter problems are concerned with the human predicament, and the human equation enters not only into the search for answers, but into the very solutions themselves. Human invention and devising are necessary ingredients of the solutions achieved. In science, however, although imagination and invention are important elements of the discovery process, the human factor must ultimately be excluded from its findings, and to this end the scientific process is designed to eliminate as much personal bias and individual error as possible. This aspect gives science its appearance of objectivity and impersonality, while bestowing a universality that transcends political and cultural differences that otherwise divide mankind.

The reader is again cautioned not to be misled by oversimplification. One must not conclude from the above orderly listing of activities and processes of thought, either that they constitute a prescribed series of steps in the scientific process or that one can identify a single scientific method subscribed to and followed by all scientists. On the contrary, individual scientists have their individual insights, styles, and methods of research. Conant is emphatic on this point:

There is no such thing as the scientific method. If there were, surely an examination of the history of physics, chemistry, and biology would reveal it. For as I have already pointed out, few would deny that it is the progress in physics, chemistry and experimental biology which gives everyone confidence in the procedures of the scientist. Yet, a careful examination of these subjects fails to reveal any one method by means of which the masters in these fields broke new ground.⁴

While there is no single scientific method, there is method, and each researcher develops his own sense of order and line of attack. And major elements of the various methods are sufficiently discernible that they can be identified. Indeed, there is enough of method to the profession to lead John Simpson, professor of physics at the University of Chicago, to assert that even the plodder, while he may never make brilliant contributions, can through systematic effort aid in the progress of science.

Nevertheless, the role of insight and perceptiveness is crucial. The application, however, cannot be equated with induction in the Baconian tradition.⁵ The inductive step from the singular to the general, while an important element in science, is far from routine. Often seemingly haphazard, this step calls into play inspiration, insight, intuition, imagination, and shrewd guesswork that are the hallmark of the productive researcher. Conant alluded to the elusive character of this phase of the scientific process: “Few if any pioneers have arrived at their important discoveries by a systematic process of logical thought. Rather, brilliant flashes of imaginative ‘hunches’ have guided their steps-often at first fumbling steps.”⁶

Each individual has his own devices for trying to discern from the particular what the general might be. Certainly the reasoner does not approach his task with no preconceptions. To the new data he adds other facts and data already known, and he calls into play previously accepted ideas that appear relevant. Whatever the method, the ultimate test is whether it works.

A continuing task of the space science manager was to assess progress in the program, and various criteria for measuring the worth of scientific accomplishments have been used. In this regard the author finds attractive a number of concepts provided by Thomas S. Kuhn.⁷

A scientist approaches a new situation or problem with a definite mental picture of how things ought to be, what processes should be operative, what kinds of results are to be expected from different experiments. This mental picture-which, with some leeway for differing points of view, he shares with scientific colleagues working in the same field-has developed over the years from experimentation and observation, hypothesizing, theorizing, and testing. It has stood the ordeal of searching tests and has proved its value in predicting new results and in integrating what is known of the field into a logically consistent, useful description of nature.

To this shared mental construct, Kuhn gives the name paradigm, a substantial extension of the usual meaning of the term. Thus, the ionosphericists share a paradigm, in which each knows-or at least agrees to accept-that there is an ionosphere in the upper reaches of the earth’s atmosphere consisting of electrons and positive and negative ions, varying in intensity, location, and character with time of day, season, and the sunspot cycle. He knows, or agrees, that most of the ionization and its variation over time are caused by solar radiation, and that the ionosphere has a complex array of solar-terrestrial interrelations. The ionosphere is affected by and affects the earth’s magnetic field. It has a profound influence on the propagation of many wavelengths in the radio frequency region of the electromagnetic spectrum and acts like a mirror reflecting waves of suitable wavelength, a phenomenon that before the advent of the communications satellite afforded the only means of round-the-world short-wave radio transmissions. To develop thoroughly the paradigm shared by ionospheric physicists would be a lengthy proposition, ⁸ but the reader may find the above sufficiently suggestive.

As another example, solar physicists share a paradigm in which the sun is regarded as an average sort of star, about 10 billion years old and with some billions of years still to go before it evolves into a white dwarf. It originated as a condensation of dust and gases from a huge nebula and was heated by the gravitational energy released by the falling of the nebular material into the contracting solar ball until internal temperatures rose sufficiently to initiate nuclear burning of hydrogen, the major source today of the sun’s radiant energy. And so on.⁹ Workers in the field of solar studies understand each other, they have a common way of looking at things, they approach problems with a similar orientation.

Individual scientists usually share a number of paradigms with different colleagues. The paradigms of the upper atmosphere physicist and the ionosphericist overlap greatly. While an ionospheric investigator is applying his ionospheric paradigm to his work, he also has in the back of his mind that the laws of physics and chemistry must apply to the ionosphere, and when appropriate the ionospheric researcher brings to bear the paradigms of chemistry and modern physics. Likewise the solar physicist must constantly borrow from the paradigms of astronomy, astrophysics, physics, nuclear physics, and plasma physics.

The importance of the currently accepted paradigm or paradigms in guiding a scientist in his researches, in determining-and determining is not too strong a word-what he will perceive when he encounters a new situation, cannot be overestimated. Even the nonscientist, by osmosis from the press, television, and literature, in addition to his formal schooling, absorbs many significant concepts from the paradigms of the working scientists. Most of the fundamental concepts about the nature of the universe shared by modern man have derived from the scientific developments of the last two centuries. With these concepts infused into one’s thinking, an enormous effort would be required to see the universe and the world as they were visualized by the medieval thinker. As Herbert Butterfield put it:

The greatest obstacle to the understanding of the history of science is out inability to unload our minds of modern views about the nature of the universe. We look back a few centuries and we see men with brains much more powerful than ours-men who stand out as giants in the intellectual history of the world-and sometimes they look foolish if we only superficially observe them, for they were unaware of some of the most elementary scientific principles that we nowadays learn at school. It is easy to forget that sometimes it took centuries to discover which end of the stick to pick up when starting on a certain kind of scientific problem. It took ages of bitter controversy and required the cooperative endeavor of many pioneer minds to settle certain simple and fundamental principles which now even children understand without any difficulty at all.¹⁰

Thus the concept of the paradigm is more than a mere convenience. In terms of the paradigm one can discern several stages in the scientific process. First of all, the existence of shared paradigms in a scientific some measure of maturity of the field. In its beginning, a newly developing field tends to fumble along without any accepted conceptual framework, and each new datum or observation may seem to heighten the complexity and confusion. In time, however, discerning minds begin to perceive some order, and a workable paradigm begins to evolve. A good example is furnished by the birth of modern chemistry in the very confused, yet highly productive, second half of the 18th century.¹¹

In its maturity a field of science exhibits alternating periods of what Kuhn refers to as normal science and scientific revolution. During a period of normal science, the accepted paradigm appears to work well, satisfactorily explaining new observations and results as they accumulate. It is a period in which measurements and observations tend to illuminate and expand upon the accepted paradigm, but not to challenge it. Most scientific work is normal science in this sense.

Occasionally new experimental results don’t appear to fit the framework of the accepted paradigm. When that occurs, attention is directed toward finding an explanation. Generally the first efforts are to find a way of retaining the accepted paradigm, particularly if it has proved highly productive and illuminating in the past. Perhaps the paradigm can be extended or even bent to accommodate the new results. In fact, the scientist’s inclination is to tolerate a considerable amount of misfit to save a particularly useful paradigm.

But when the challenge to the previously accepted paradigm becomes too severe, and acceptable modifications or extensions won’t accommodate the new results, then a change in paradigm becomes necessary. Such periods, bringing a forced change of paradigms, Kuhn designates as scientific revolutions. Periods of scientific revolution are likely to be exciting (at least to scientists), highly active, with much debate and a lot of fumbling around trying to find a way out. Classical examples of scientific revolutions are furnished by the shift from Newtonian to Einsteinian relativity and from classical to quantum physics.¹² A more recent example is to be found in the upheavals of the 1950s and 1960s in geophysics and geology leading to the now general acceptance of the concepts of sea-floor spreading, continental drift, and plate tectonics as fundamental features of the paradigm that today guides the researcher in experimenting and theorizing about the nature of the earth’s crust.¹³

For this book the concepts of paradigm, normal science, and scientific revolution furnish a way to trace and assess the development of space science through the first decade or so of NASA’s existence. Nevertheless, the reader is cautioned that the concept of the paradigm in the scientific process-or the manner in which the concept is used-has been extensively criticized.¹⁴ A major concern has been the difficulty of supplying the concept with any great degree of precision and the consequent fuzziness in the picture one can draw of the role really played by the paradigm in science. Critics have pointed out that Kuhn himself has used the concept in numerous different ways. Also, the simultaneous existence at times of conflicting paradigms, each receiving support from its separate group of adherents-as, for example, in the many years during the 18th century when both the caloric and mechanical theories of heat had their supporters-is pointed to as indicating that Kuhn’s concept of scientific revolution is too simplistic to embrace the hole picture of ho science moves and how revolutions occur in scientific.

In spite of the criticism the paradigm appeals to the author as useful and even fundamental; he suspects the criticism can be met. At any rate, for this book the straightforward interpretation of the role of paradigm in science will suffice and should be useful.

SPACE SCIENCE

This book is about space science. The subject is simple in concept, comprising those scientific investigations made possible or significantly aided by rockets, satellites, and space probes. But in its realization space science turns out to be very complex because of the diversity of scientific investigations made possible by space techniques.

Interest in the phenomena of space is not recent, its origins being lost in the shadows of antiquity. Impelled by curiosity and a desire to understand, man has long studied, charted, and debated the mysteries of the celestial spheres. Out of this interest came eventually the revolution in thought and outlook initiated by Copernicus, supported by the remarkably precise measurements of Tycho Brahe, illuminated by the observations of Galileo and the insights of Kepler, and given a theoretical basis by Newton in his proposed law of gravitation. The Copernican revolution continues to unfold today in human thought and lies at the heart of modern astronomy and cosmology. ¹⁵

Yet, until recently outer space was inaccessible to man, and whatever was learned about the sun, planets, and stars was obtained by often elaborate deductions from observations of the radiations that reached the surface of the earth. Nor were all the inaccessible reaches of space far away. The ionosphere, important because of its role in radio communications, was not as far away from the man on the ground below as Baltimore is from Washington. Nevertheless, until the advent of the large rocket, the ionosphere remained inaccessible not only to man himself but even to his instruments. As a result many of the conclusions about the upper atmosphere and the space environment of the earth were quite tentative, being based on highly indirect evidence and long chains of theoretical reasoning. Time and again the theorist found himself struggling with a plethora of possibilities that could be reduced in number only if it were possible to make in situ measurements. Lacking the measurements, the researcher was forced into guesswork and speculation.

Small wonder, then, that when large rockets appeared they were soon put to work carrying scientific instruments into the upper atmosphere for making the long-needed in situ measurements. From the very start it was clear that the large rocket brought with it numerous possibilities for aiding the investigation and exploration of the atmosphere and space. It could be instrumented to make measurements at high altitude and fired along a vertical or nearly vertical trajectory for the purpose, falling back to earth after reaching a peak altitude. When so used the rocket became known as a sounding rocket or rocket sonde, and the operation was referred to as sounding the upper atmosphere.

A rocket could also be used to place an instrumented capsule into orbit around the earth, where the instruments could make extended-duration measurements of the outer reaches of the earth’s atmosphere or observations of the sun and other celestial objects. Or the rocket might launch an instrumented capsule on a trajectory that would take it far from the earth into what was referred to as deep space, perhaps to visit and make observations of the moon or another planet. The orbiting capsules were called artificial satellites of the earth; those sent farther out came to be known as space probes or deep space probes. Finally, the ultimate possibility of carrying men away from the earth to travel through deep space and someday to visit other planets emphasized dramatically the new power that men had acquired in the creation of the large rocket.

A language of rocketry emerged, which the news media popularized. Familiar words took on new meanings, and new terms were encountered: artificial satellite, spacecraft, space launch vehicle, rocket stages, countdown, liftoff, trajectory, orbit, tracking, telemetering, guidance and control, retrorockets, reentry-and space science.

Through all the centuries of scientific interest in space phenomena, the phrase space science had not gained common use. That the terminology did not come into use until after rockets and satellites brought it forth gives force to the definition of space science given at the start of this section. That definition sets forth the meaning in mind when in June 1957 the U.S. National Academy of Sciences combined the functions of the IGY Technical Panel on Rocketry and the IGY Technical Panel on the Earth Satellite Program into a single board, naming it the Space Science Board. That is the meaning implied by the discussions in the first book-length publication by the Space Science Board a few years later.¹⁶ That is the meaning picked up by Samuel Glasstone in 1965 in his comprehensive survey of space science:

The space sciences may be defined as those areas of science to which new knowledge can be contributed by means of space vehicles, i.e., sounding rockets, satellites, and lunar and planetary probes, either manned or unmanned. Thus space science does not constitute a new science but represents an important extension of the frontiers of such existing sciences as astronomy, biology, geodesy, and the physics and chemistry of Earth and its environment and of the celestial bodies. ¹⁷

While the basic meaning of space science was clear and unvarying from the start, the exact nature of the activity, and in particular its relationship to the rest of science, was not always so clear. Glasstone’s use in the above quotation of space sciences in one place and space science in the very next sentence reflects one question that arose often during the first years of the NASA program. Is space science a new scientific discipline^* or, if not yet, will it in time develop into a new discipline? The question arose primarily because of the pure-science character of space science and the strong coherence that quickly developed in the field, but also because of the broad range of scientific topics to which research was addressed. The initial answer to the question generally agreed to by those in the program was that given by Glasstone: space science was not a new discipline and should not be expected to become one. The initial response was probably intuitive, but in retrospect it is seen to have been the correct answer.

Space science makes extensive contributions to geophysics; but this part of space science remains a part of the discipline of geophysics, using its techniques and instrumentation and employing and extending its basic theory-sharing its paradigm, that is. The researchers using space techniques for geophysical investigations, while perhaps thinking of themselves as space scientists, continue to call themselves geophysicists, to be members of geophysical societies like the American Geophysical Union, to present their papers at geophysical meetings and to publish them in geophysical journals.

Space science also makes numerous contributions to astronomy, but again the parts of space science devoted to astronomy remain a part of the discipline of astronomy, and space scientists using rockets for astronomical research continue to view themselves as astronomers. Their results are presented at meetings like those of the American Astronomical Society or the International Astronomical Union^** and are published in their journals or proceedings.

Cosmic ray physicists find space methods advantageous in many of their researches, but continue to be cosmic ray physicists first and space scientists only incidentally. Examples can be multiplied at length.

Nevertheless, for several years following Sputnik the thought that space science might evolve into a separate discipline persisted. One can understand why. The demands imposed by rockets and spacecraft on the running of a science program were severe, giving a coherence to the field akin to that characteristic of a scientific discipline. But rockets and spacecraft did not rest upon or stem from the scientific disciplines they served. Rather, they were simply trucks to provide transportation to otherwise inaccessible places, while the genuine techniques and instrumentation of the investigations were those of the individual disciplines that benefited from the new means of transportation.

To emphasize the diverse scientific disciplines, writers sometimes chose to use the phrase space sciences . At other times authors used science in space to imply that space science was not separate from science on the ground and was neither more nor less than the familiar, everyday science carried out in a new arena. These initial uncertainties were reflected in the changing names given to the space science group in NASA Headquarters by the author and his colleagues. In 1958 and 1959 the division in the Office of Space Flight Development that had responsibility for scientific research in space was labeled Space Science. When NASA Headquarters reorganized under the new administrator, James E. Webb, the space science program was elevated to the level of a separate office, which called attention to the plural nature of its activity in its title: Office of Space Sciences. Finally, in the reorganization of 1963 that brought science and applications together under one head, NASA settled on space science as its choice for the rest of the 1960s, designating the new entity as the Office of Space Science and Applications. ¹⁸

If space science had been distinctly separate from the rest of science, NASA might well have felt less impelled to draw in the wide participation that the agency encouraged in the program. As it was, recognizing that no single agency could reasonably expect to bring within its own halls the expertise needed for all the separate disciplines, NASA consciously sought broad participation from the outside scientific community, especially from the universities, where the greatest interest in pure science was to be found.

Within the universities the question arose in a somewhat different form. As the numbers of those entering space science research grew apace, a need to provide training for new scientists who might wish to pursue space research as a career became evident. Should this be done by setting up departments of space science in universities? The instinct of NASA program managers was not to do so, and when asked they advised against it, recommending instead that opportunities be provided within the traditional departments of astronomy, physics, geophysics, geology, etc., for taking on space-related problems as thesis topics. Most universities saw it this way, although a few decided to experiment with separate space science departments.^****

The inseparability of space science from the rest of science and the broad range of disciplines to which space techniques promised to contribute gave impetus to the rapid development of science in the national space program. It must be emphasized that scientists came into the program with problems that had been under attack by other methods and that appeared to need some new approach if they were to be solved. The promise to provide that new approach drew researchers first to sounding rockets and later to satellites and space probes.

Writing about six years after the start of sounding rocket research in the United States, in what was probably the first book devoted to the subject, the author was able to find in the scientific literature significant results to report on upper atmospheric pressures, temperatures, and densities; atmospheric composition; solar radiations in the ultraviolet and x-rays; upper-air winds; the ionosphere and the earth’s magnetic field; cosmic rays; and high-altitude photography. A year later the list was extended even further in a book reporting the papers presented at the first international conference on the subject of high-altitude rocket research, arranged by the Upper Atmosphere Rocket Research Panel (see chap. 4) of the United States and the Gassiot Committee of the Royal Society of London.¹⁹ In 1956, just a decade after the start of rocket sounding of the upper atmosphere, the Upper Atmosphere Rocket Research Panel, extrapolating from its sounding rocket experience, turned its attention to the researches that would be possible with instrumented satellites of the earth. These deliberations were published in the first book on the subject to be assembled by persons professionally engaged in high-altitude research. ²⁰ To the research topics listed above, the book added some new ones: meteors and interplanetary dust, particle radiations from the sun, the aurora, stellar astronomy, meteorology, and geodesy. The potential contributions to science of both manned and unmanned spacecraft were discussed in the Space Science Board’s first book. While most attention was devoted to unmanned exploration of space, the ultimate potential of manned spaceflight was recognized in such words as: “The significant and exciting role of man lies in the exploration of the Moon and planets.” ²¹

Such scientific investigations, made possible by sounding rockets and spacecraft, came to define what is meant by space science. Much of the potential of space science was already discernible before ever a satellite had been launched, and by the end of 1960-by which time the first NASA administrator, Keith Glennan, had set the agency firmly on its course-the broad sweep of space science was fully apparent. By the end of a decade space science research had become worldwide, and a steady flow of results was pouring into the literature. ²²