Artificial Earth satellites

Serious thinking about reaching farther from the Earth’s surface for scientific research began immediately after the cessation of hostilities at the end of World War II. As

CHAPTER 3 • THE INTERNATIONAL GEOPHYSICAL YEAR 71

stated earlier, atmospheric sounding rockets were widely employed throughout the post-1945 era. But the need for much longer-term observations at higher altitudes was widely recognized.

Early U. S. thinking about satellites In May 1945, soon after his surrender to Allied troops in Germany, Wernher von Braun summarized his views on the potential of rocket-launched satellites for his U. S. Army captors.12 Discussions of satellite possi­bilities within the Army stimulated Navy interest, where the primary initial emphasis was on the observation of ship movements at sea. In October of that year, the Navy became the first U. S. agency to take a major formal step to evaluate the prospects. Its Bureau of Aeronautics set up a Committee for Evaluating the Feasibility of Space Rocketry. That group soon recommended that the design of an instrumented Earth satellite be started.

In December 1945, the Guggenheim Aeronautical Laboratory (later renamed the Jet Propulsion Laboratory) at the California Institute of Technology was given a con­tract to investigate the relationship between carrier vehicle performance, the weight of a satellite, and the height of its orbit. The first result of the Guggenheim study was to point out that the system initially envisioned was too expensive to be supported by then-extant Navy budgets. At that point, the Navy tried to enlist help from the other services. A meeting was held on 7 March 1946 between Navy and Army officials, but the U. S. Army Air Corps declined the invitation to participate. What the Air Corps neglected to mention was that they were starting their own investigation, and they had no intention of sharing their efforts with the Navy.

In a November 1945 report, Air Corps general Henry H. (Hap) Arnold expressed his belief that a spaceship “is all but practicable today.” The next month, an air corps scientific advisory group stated that long-range rockets were feasible, and satellites were a “definite possibility.” In early 1946, the Air Corps commissioned a very highly classified independent study, partly to demonstrate that they, in addition to the Army Ordnance group and the Office of Naval Research, possessed competence in this arena and were qualified to assume responsibility for military satellite missions. Project RAND (standing for “Research ANd Development”) was set up by the air corps within the Douglas Aircraft Company at its El Segundo, California, plant to undertake that study.

That group achieved the remarkable feat of producing its first (classified) report, Preliminary Design of an Experimental World Circling Spaceship, by 2 May 1946.13 That 324 page report envisioned a 500 pound satellite to be launched by a booster that would use the technology obtained from V-2 experience. In addition to its technical assessments, the report identified a number of potential military missions for such a spacecraft, including observation, attack assessment, communications, weather recon­naissance, weapons delivery, and the technological development of missile guidance. There was also a strong focus in the report on the gathering of scientific information

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Подпись: 72about the Earth and its near-environment. The report made the following prescient observation:

Though the crystal ball is cloudy, two things seem clear:

(1) A satellite vehicle with appropriate instrumentation can be expected to be one of the most potent scientific tools of the Twentieth Century.

(2) The achievement of a satellite craft by the United States would inflame the imagination of mankind, and would probably produce repercussions in the world comparable to the explosion of the atomic bomb.

The problem outlined in the report was that the cost was expected to be $150 million, a prohibitive amount for that era. A year later, RAND presented a new plan for a smaller satellite that it claimed could be launched for $82 million. But a technical evaluation by a Department of Defense group under Clark B. Millikan reviewed both the Air Corps and Navy plans and reported that the identification of some specific military uses would be required before a military development project could be justified. The final nail was driven in the coffin of those earliest efforts to develop an actual military Earth satellite on 15 January 1948, with Vice Chief of Staff Hoyt S. Vandenberg’s delaying statement that “satellites should be developed at the proper time.”14

Thus, by the opening of the 1950s, there was a strong agreement within military circles that satellite launches were possible. Although many of the suggested jus­tifications for launching military satellites did not appear to warrant the high cost, there was an additional factor. Throughout the cold war era, there was an urgent need for intelligence information to assist in assessing USSR military capabilities. U. S. aircraft photoreconnaissance overflights were made, but the Soviets strongly objected to them, the aircraft were detectable by radar, and they were vulnerable to antiaircraft fire from the ground. But, although satellites offered the possibil­ity of reconnaissance from above the range of ground fire and aircraft, U. S. policy makers were seriously concerned that the Soviets would object to them as a sim­ple extension of what they viewed as the warlike lower-level aircraft flights. The Soviets might then be expected to develop an antisatellite capability, and Earth orbit would become just another battlefront, rather than an outpost for a broad range of uses, including peaceful scientific exploration of the universe and the application of space technology to Earth resource management, communications, and other practical uses.

Within the nonmilitary arena, concrete thinking about space flight was also evident immediately following the war. In 1946, staff researchers at the Naval Research Laboratory (NRL) discussed the use of Earth satellites for unclassified high-altitude research. The idea was set aside at that time as being premature—they concluded that the state of the technology was simply not yet available.

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The scientist’s hopes for research in space remained only a dream into the early 1950s. The popular press began to help in spreading the word. Although many of the concepts discussed openly did not benefit directly from the military studies because of the latter’s high security classification, an expectant culture of serious space en­thusiasts slowly emerged. The American Rocket Society began pressing the case for the scientific and peaceful conquest of space in the opening years of the 1950s. It established a Space Flight Committee in 1952, with Milton W. Rosen of the NRL as chairman. The following year, that committee, after being provided with at least some of the sensitive military information, issued a classified report with details about the kinds of actions that would be required to promote space flight. They suggested that the “National Science Foundation study the utility of an unmanned satellite vehicle to science, commerce and industry, and national defense.” They went on to state that “examples of these research uses might be: for a superior astronomical observatory site; for biological and chemical research utilizing non-gravity conditions; for elec­tronic research utilizing a more perfect vacuum of unlimited volume for microwave research in free space; cosmic ray studies; and sophisticated nuclear research; etc.”

A year later (1954), the Space Flight Committee followed its earlier report with an unclassified report to the National Science Foundation titled “On the Utility of an Artificial Unmanned Earth Satellite.” It stated that a satellite would be one of the most important steps toward advancing the cause of space flight, and that it would also increase the country’s scientific knowledge.

Since the IGY was undertaken as a completely open, purely scientific international effort, its planning involved a huge body of scientists, many of whom were unaware of most of the classified military activity. Those who did know about it were constrained from discussing it in the unclassified IGY planning arena.

The possibility of using satellites for scientific research became much more openly discussed following an event that occurred in 1952. Fred Singer began presenting and publishing a series of unclassified papers that espoused the use of small artificial Earth satellites for scientific investigations.15>16>17>18>19>20 As summarized later by Singer:

Partly stimulated by lectures I gave to the British Interplanetary Society in London in 1951,1 developed ideas for an instrumented earth satellite to carry on the kinds of measurements we hadbeendoinginrockets…. It was quitearadical ideaat the time, whichoffendedthosewho pooh-poohed any notion about working in space as well as those who had already set their aim on manned exploration of the solar system. What I brought to the discussion, mainly, was the notion that instrumentation could be miniaturized and that useful research could be done with a satellite weighing only a few kilograms—even if it survived only for days or weeks….

So was born the MOUSE—the Minimum Orbiting Unmanned Satellite of the Earth—with the help of futurist Arthur C. Clarke and rocket engineer Val Cleaver and some alcoholic conviviality at the Players’ Club near Trafalgar Square. For the next few years, I would try to think of all kinds of experiments that could be done by such a satellite: meteorological observations, including worldwide measurements of ozone; ultraviolet measurements of the

OPENING SPACE RESEARCH

Подпись:Sun and other stars; measurements of incoming interplanetary dust as well as the zodiacal light/solar dust corona; magnetic measurements of ionospheric currents; the use of the satellite lifetime to measure the density of the upper atmosphere; primary cosmic rays, and finally, geomagnetically trapped particles. All these ideas were duly worked out and published in some detail.21

Singer’s implied claim to have originated the idea of a small, instrumented satellite was greeted with discomfort by much of the scientific community. As related by Homer E. Newell in his book on the early history of space science:

Members of the Upper Atmosphere Rocket Research Panel were aware of these [early military satellite] studies, but those who were employees of the military did not feel free to press the issue. As has been seen, the panel recommended only a sounding rocket program to the Academy of Sciences [for the IGY]. But geophysicist S. Fred Singer of the Applied Physics Laboratory, who had been conducting cosmic ray and magnetic field research in sounding rockets, felt under no restraints of military security. From some fairly simple calculations, Singer concluded that it should be possible to place a modest (45-kilogram) satellite in orbit around the Earth, and at every opportunity, he urged that the country undertake to do so. Singer’s conclusions were qualitatively correct, but his outspokenness generated some friction for at least two reasons. First, Singer’s manner gave the impression that the idea for such a satellite was original with him, whereas behind the scenes many had already had the idea, and they felt that Singer had to be aware of this. Muzzled by classification restrictions, they could not engage Singer in debate. Second, being unable to speak out, those who had dug into the subject in much greater depth could not point out that Singer’s estimates overshot the mark somewhat, and that his suggested approach was not as workable as others that couldn’t be mentioned.22

Singer continued to press his ideas for the MOUSE. His next step was also chron­icled by Newell:

Singer gained international attention for his proposal when, in August 1953 at the Fourth International Congress on Astronautics in Zurich, he described his idea for a Minimum Orbital Unmanned Satellite Experiment, which he called MOUSE. MOUSE would weigh 45 kilograms, and would be instrumented for scientific research.

The International Scientific Radio Union, at its 11th General Assembly in The Hague, gave support to Singer’s proposal. At the urging of both Singer and Lloyd Berkner, on 2 September 1954 the Radio Union [International Scientific Radio Union, or URSI] adopted a resolution drawing attention to the value of instrumented earth satellites for solar and geophysical observations. Later that month, on 20 September, the International Union of Geodesy and Geophysics [IUGG] at its 10th General Assembly in Rome adopted an even stronger resolution, actually recommending that consideration be given to the use of small scientific satellites for geophysical research. Both the resolution of the Union of Geodesy and Geophysics and the earlier one of the Radio Union were conveyed to CSAGI, which held its third general planning meeting in Rome shortly after the close of the Geodesy and Geophysics Union meeting.23

The URSI resolution recognized “the extreme importance of continuous obser­vations from above the E-region of extra-terrestrial radiations, especially during the forthcoming IGY.” It went on to state, “URSI therefore draws attention to the fact that an extension of present isolated rocket observations by means of instrumented

CHAPTER 3 • THE INTERNATIONAL GEOPHYSICAL YEAR

Earth satellite vehicles would allow the continuous monitoring of solar ultra-violet and X-radiation intensity and its effects on the ionosphere, particularly during solar flares, thereby greatly enhancing our scientific knowledge of the outer atmosphere.”24

The CSAGI satellite challenge The IUGG quickly followed that resolution with an even stronger formal resolution. It was presented to the CSAGI for action, and on 4 October 1954, the CSAGI passed a very slightly edited version of the IUGG resolution. It read:

In view of the great importance of observations during extended periods of time of extra­terrestrial radiations and geophysical phenomena in the upper atmosphere, and in view of the advanced state of present rocket techniques, the CSAGI recommends that thought be given to the launching of small satellite vehicles, to their scientific instrumentation, and to the new problems associated with satellite experiments, such as power supply, telemetering, and orientation of the vehicle.25

That resolution officially introduced the prospect of artificial Earth satellites into the planning for the IGY program. Exactly three years later, the first satellite was launched.

The U. S. response to the challenge The U. S. response to the CSAGI challenge took some time. Homer Newell’s excellent account of this history reads:

The U. S. National Committee for the IGY gave careful consideration to the proposal during the spring of 1955. Support was not immediately unanimous. Clearly the dimensions of this undertaking would be of a different order from the sounding rockets already a part of the IGY planning. Doubts were expressed over the wisdom of including the project in the IGY. Technical aspects were not the only considerations. There was also the concern about what would be the reaction of people to the launching of an artificial satellite that could easily be viewed as an eye in the sky, could well be accorded some sinister import, perhaps even be equated with some kind of witchcraft. Memories of Orson Welles’s Mars invasion had by no means vanished. Most, however, favored endorsing the project. Joseph Kaplan, chairman of the committee, was especially enthusiastic and jokingly coined the phrase “Long Playing Rocket” for the satellite, by analogy with the long-playing records newly on the market. He suggested that, since sounding rockets had become familiar, the idea of a long-playing rocket would prove less disturbing than the completely new concept of an artificial satellite.26

Eventually, the National Academy of Sciences (as sponsor of the U. S. IGY program) and the National Science Foundation (which provided the money) sought approval of a U. S. Earth satellite program. On 29 July 1955, President Dwight D. Eisenhower announced the decision to launch “small, unmanned, Earth-circling satellites as a part of the U. S. participation in the IGY.” That announcement was made simultaneously in Washington, D. C.; in Brussels, Belgium, at a meeting of the CSAGI in the marble great hall of the Academy Palace; and in the 40 countries participating in the IGY.27 With that announcement, organizing the U. S. program shifted into high gear.

The three U. S. armed forces vied for the assignment to plan and execute the satellite technical program. Through a process described in detail in Chapter 7,

OPENING SPACE RESEARCH

Подпись:that responsibility was ultimately assigned by the Secretary of Defense to the Navy Department on 9 September 1955. In turn, the navy secretary assigned it to the Chief of Naval Research on 27 September, and the director of the NRL was given the task of executing it on 6 October.

The National Academy of Sciences retained the responsibility for policy guidance and for interfacing with the various individuals and organizations of the IGY. That responsibility included the prioritization and selection of the experiments.

In early October 1955, the U. S. National Committee for the IGY established a Technical Panel on the Earth Satellite Program, with Richard W. Porter as chairman. It held its first meeting on 20 October. In late January 1956, Porter asked Van Allen to chair a new Working Group on Internal Instrumentation (WGII). At the same time, he asked William H. Pickering to set up a companion Working Group on External Instrumentation (WGEI). The WGII was concerned with the scientific instruments to be flown, while the WGEI dealt with telemetry and tracking. All three groups undertook their work with great alacrity.

In the final analysis, it is virtually certain that the perceived need to develop a U. S. satellite for military needs served as a significant factor in gaining administration support for the IGY satellite effort. The IGY provided a convenient “open, pure science” cover that helped to ensure that U. S. satellites would be accepted in the international political arena.

Initial official soviet actions Although Soviet interest in space flight was also long­standing, the Soviets were slower to reveal their thinking to the outside world in any formal sense. As mentioned earlier, by the time of the 20 September 1954 meeting of the IUGG, the USSR had not even officially committed to participating in the IGY. By early 1956, that commitment had been made, and their IGY Committee was invited by a special letter from the CSAGI secretary-general, Marcel Nicolet, to consider participating in the rockets and satellites program.

Although the invitation was apparently received with great interest in the Soviet Union, no formal announcement of Soviet plans to launch an Earth satellite was made to the outside world until that fall. On 11 September 1956, Academician Ivan P. Bardin announced to the delegates at the Fourth General Assembly of the CSAGI in Barcelona that the USSR would have a rocket program in the IGY and “would use satellites for pressure, temperature, cosmic ray, micrometeor, and solar radiation measurements.”

It was not until 10 June 1957 that Bardin revealed any further details about the Soviet program to the IGY planners. This was done via letter to the CSAGI Reporter on Rockets and Satellites. In that letter, he mentioned that 125 meteorological rockets would be launched from the Arctic, central USSR, and Antarctic. He also mentioned

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the satellites again, stating that all of the rocket and satellite launches would study “the structure of the atmosphere, cosmic rays, the ionosphere, micrometeors and meteorites, the physical and chemical properties of the upper astrosphere, and more.” But other details, such as the number of planned satellite launches and their sizes, were not revealed.

Although I did not attend the CSAGI and other early international IGY planning meetings, I did observe and participate in much of the detailed planning for the U. S. IGY satellite program throughout 1956 and 1957. The information above was the limit of my knowledge about the Soviet intentions, and I believe that was true for the majority of civilian scientists involved in the U. S. program. We were largely unaware of the many other indicators of Soviet space activity that are detailed in Chapter 6.

The U. S. Vanguard Satellite Program Once the NRL received the assignment for developing the U. S. satellite in early October 1955, work quickly accelerated. The first substantive outline of the form of the U. S. satellite (by that time known as Vanguard) was presented in late November by Homer Newell to the Technical Panel on the Earth Satellite Program.28 He stated that the NRL concept employed two concentric spheres: an outer one, to be 20 or 30 inches in diameter, and an internal, 12 inch diameter sphere to house most of the scientific instruments. The shape of the outer sphere was chosen to optimize optical tracking and the conduct of scientific experiments related to atmospheric drag. Although it was thought then that the inner container should be spherical to help in controlling the temperature of the internal instruments, later study allowed it to be changed to a cylindrical form that permitted more efficient packaging.29

In that early concept, each of the two spheres was to be pressurized independently with helium, although the satellite was to be able to operate even if pressure in the outer sphere was lost due to punctures by small particles (micrometeorites) that were expected to be present in orbit.

That early design posited a total satellite weight of about 22 pounds, with about 2.2 pounds available for scientific instruments, exclusive of telemetry and batteries. It was stated that the data would be recovered by the Minitrack tracking and telemetry system then being developed at NRL under John T. Mengel’s leadership. The antici­pated periods of usable data reception during passage over each ground station were expected to be from eight seconds to as long as a minute for transits that passed directly overhead.

Some of the U. S. scientists were greatly troubled by the small instrument weight allocation. Van Allen suggested during January 1956 that the project consider making some of the satellites cylindrical in shape, with a length of about 18 inches and a diameter of 6 inches. He referred to this as the Mark II configuration.30 The intent of his recommendation was to make more of the total satellite weight available for

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Подпись:scientific instrumentation. It should be noted that the Mark II configuration was similar to the satellites that were ultimately launched as the early Explorers.

Some of Van Allen’s preference for the six inch diameter, no doubt, resulted from our group’s experience with that size for the Deacon-based rockoon instruments. And, although he could not discuss it in the unclassified sessions, it is likely that his preference was also strongly influenced by his knowledge of the highly classified Jupiter C developments then under way at the Army Ballistic Missile Agency at Huntsville, Alabama. Van Allen became aware of those developments as early as 1954, when Ernst Stuhlinger, from the Huntsville team, told him of the possibility that the Army might be able to launch a satellite with its rockets. It had been, in fact, that knowledge that most directly motivated Van Allen to prepare his first (November 1954) proposal for a satellite-borne cosmic ray instrument. That background is described in greater detail in Chapter 7.

Major progress had been made in the Vanguard planning by early February 1956. The diameter of the outer shell was set at about 20 inches, in order that it would fall within the envelope of the third stage of the proposed Vanguard launch vehicle. In addition, the configuration for the inner instrument package was changed to a 3.5 inch diameter cylinder with a variable length, depending on the instruments. The satellite maximum weight had been set at 21.5 pounds, with 2 pounds allocated for the experimenters’ instruments (again, exclusive of telemetry and batteries).31

The issue of the satellite configuration remained open for some time. As late as 30 May 1956, two weight breakdowns were still being carried: one for the spherical form favored by NRL and the other for the cylindrical form preferred by Van Allen and several others.32

The issue was finally settled by a compromise of sorts. The outer shell for all the satellites would remain spherical with a diameter of 20 inches, but the specifications for the inner package were amended to permit either a 3.5 inch or a 6 inch diameter instrument cylinder. Although that did not make as much weight available for the scientific instruments as the Mark II configuration would have provided, the 6 inch instrument configuration did permit more efficient packaging.

The Vanguard satellite hardware Upon receiving approval of the Vanguard project in early October 1955, NRL began working diligently to develop the satellite’s shells, thermal control systems, transistor circuitry, telemetry and tracking systems, and other capabilities that would be required. Progress on those fronts (as well as on the launch vehicle and other Vanguard components) is recorded in a series of 36 detailed reports, the first one dated 13 January 1956. In their third report, dated 29 March 1956, they outlined three satellite designs. They were described as follows:

(1) A minimum-weight satellite containing only Minitrack equipment—the size and

shape would be consistent with the equipment and weight requirements. From a weight

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standpoint, it would be preferable to attach the sphere solidly to the third-stage shell and omit spin-isolation bearings and separating devices. The temperature and acceleration effects on the structure and equipment are being investigated. The weight of this satellite might be as little as eight pounds; it would not be more than eleven pounds.

(2) A 20-inch spherical satellite weighting 21.5 pounds—it would contain a Minitrack and telemetering transmitter; temperature, pressure, and erosion gauges; and equipment for the measurement of variations in solar Lyman-alpha radiation. It would be mounted on a bearing to reduce the spin rate, and a separating mechanism would cause the satellite to leave the third-stage case at about five feet per second after burnout.

(3) A satellite which would contain the same instrumentation as (2), but might remain attached to the third-stage case and would have an optimum configuration which has not yet been established.

The final choice of the satellite type will be made at a future date.33

The planning, then, was that the first small (six inch) satellites would be built for test vehicle developmental launches, while either the second or third configuration would serve as the full IGY scientific instrument-carrying satellite.

The small satellite was, in fact, placed atop test vehicles (TVs) TV-3 (unsuccessfully attempted on 6 December 1957), TV-3BU (unsuccessfully attempted on 5 February 1958), and TV-4 (successfully launched as Vanguard I on 17 March 1958).34 The third design listed above was dropped fairly early in the program.

The second design evolved into the configuration that was ultimately used for six all-up IGY launch attempts, beginning with the (unsuccessful) launch of TV-5 on 28 April 1958. The one successfully launched on 17 February 1959 atop Satellite Launch Vehicle 4 (SLV-4) was Vanguard II. Vanguard III, launched on 18 September 1959, employed a more powerful third stage, permitting a heavier satellite.

It has been reported from time to time that the small satellites included in the failed launch attempts in December 1957 and February 1958, and successfully launched as Vanguard I in March 1958, were the result of a last-minute crash effort to get a payload into orbit as quickly as possible after the Sputnik 1 launch. In fact, as stated above, the 6.44 inch diameter satellite was always planned as a part of the Vanguard launch vehicle development program.

The number of failed Vanguard vehicle launch attempts may seem excessive at first reading. But it was not so by the standards of rocket development at that time. The Vanguard, during its full development and operational period, made a total of 14 launch attempts, including both early rocket developmental tests and all-up satellite launch attempts, of which there were eight failures.

By comparison, the V-2 rockets assembled in the United States following World War II experienced 20 failures out of 64 attempts, even though thousands of the operational rockets had been launched from Germany by that time, and the U. S. operations were overseen by the German scientists who had helped design them. The development of the Redstone rocket up to its elevation to operational status included 37 test flights, of which 10 were failures. The Thor IRBM, during its developmental

Подпись: 80OPENING SPACE RESEARCH

Artificial Earth satellites

TABLE 3.1 Early U. S. Launching Scorecard

Year

Successes

Failures

Percentage

Success

1957

0

1

0

1958

7

10

41

1959

11

8

58

1960

16

13

55

1961

29

12

71

1962

52

7

88

1963

38

8

83

1964

57

7

89

1965

63

7

90

1966

73

4

95

testing period, made 10 launch attempts, of which 6 were failures. The first version of the Atlas, designated Atlas-A and consisting of only the main sustainer stage with a planned range of 600 miles, experienced five failures out of eight attempts.

Table 3.1 shows the total number of U. S. space launch attempts during the first 10 years of the Space Era, and the percentage of those attempts that succeeded.

Of the eight satellite instruments that I developed at Iowa before my departure in September 1960, only half were successfully launched into orbit. The success-to – failure ratio improved slowly during the next few years. It was only in 1965 that the space launch success rate reached 90 percent.

The Soviets fared no better. The public perception of their success was better, as they hid their failures until much later. In actual fact, during the years 1957 through 1960, they made 19 launch attempts, of which only 9, or 47 percent, were successful.

Experiment selection Long before the announcement in July 1955 of a plan to launch a U. S. satellite, ideas for space-based investigations had been gestating in many minds. The president’s decision and announcement provided a great stimulus for further thinking. The first concrete experiment proposal was Van Allen’s, dated 28 September 1955, to study cosmic rays.35 It was followed a few weeks later by a proposal by Fred Singer at the University of Maryland to measure the erosion of the satellite’s skin by meteoric dust.36 And the competition for real estate on the enthusiastically anticipated satellite was off and running.

The UARRP, mentioned earlier as being formed during the V-2 rocket-launching era, had continued its activity into the IGY planning period. Following the president’s July announcement, that body quickly made concrete plans for examining potential satellite experiments. They ended their meeting on 27 October 1955 at the Ballistics Research Laboratories in Aberdeen, Maryland, with a decision to hold a symposium to discuss ideas for such experiments. The guidelines that they established for that symposium stipulated that attendance would be limited to panel members and their

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invitees, that only unclassified materials would be considered, and that the subject matter would be highly constrained to be specific, critically considered, and pertinent within the constraints of the present and near-term projection of technologies. The meeting was open for “plans for physical experiments and observations, theoretical and interpretative matters, and techniques and components of a novel nature, but not space medicine, or the legal and political aspects of the satellite program, or essays dealing with vehicle propulsion and guidance.”37

That symposium took place on the campus of the University of Michigan at Ann Arbor on 26-27 January 1956. The forty-third meeting of the UARRP, it was also billed as their Tenth Anniversary Meeting. It provided an opportunity for scientists to present their ideas for space research in an informal, collegial environment. The proposals for both passive and active satellite-based experiments encompassed a wide span of disciplines, including meteor and interplanetary dust characteristics, air pres­sure and density, hydrogen distribution, meteorological measurements, ionospheric structure, temperature, electron density, electromagnetic propagation, auroral radia­tion, magnetic field, Earth heat transfer, solar Lyman-alpha emission, solar stream particles, ultraviolet stellar magnitudes, and, of course, cosmic rays. Thirty-three of those proposals were later published in book form.38

I accompanied Van Allen to that Ann Arbor symposium. It was a watershed experience for me, as it greatly broadened my perspective of scientific research in general, and of the up-and-coming space program in particular. After that meeting (and my concurrent undergraduate graduation), and in advance of official action to select the scientific experiments to be funded by the IGY program, I began substantive work on developing Van Allen’s instrument, as related in detail in Chapter 5.

Immediately after that meeting, at the beginning of February 1956, the newly formed WGII, under Van Allen’s chairmanship, took over the responsibility for all aspects of the instrumentation to be carried on the IGY satellites, including appraising the many proposals being suggested. Initial members of that group were Leroy R. Alldredge (Johns Hopkins Operations Research Office), M. Ference (Ford Motor Company), Herbert Friedman (NRL), William (Bill) W. Kellogg (RAND), Richard Porter (General Electric), Lyman Spitzer (Princeton University), and Van Allen (as chairman).39,40

Thirty serious proposals were initially considered by the WGII. By the time of its first actual meeting on 2 March 1956, the list to be evaluated stood at 11, with 4 more needing additional clarification. They set about energetically to reduce that list to a priority-ordered list that could be flown on the six launch vehicles being procured. The four criteria on which they settled for ranking the proposals were as follows:

(a) Scientific Importance. This aspect was taken to be measured by the extent to which the proposed observations, if successful, would contribute to the clarification and understanding

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Подпись: 82of large bodies of phenomena and/or by the extent to which the proposed observations would be likely to lead to the discovery of new phenomena.

(b) Technical Feasibility. This criterion encompassed evidence for previous successful use of the proposed technique in rockets (or otherwise), apparent adaptability of the instru­mentation to the physical conditions and data transmission potentialities of presently planned satellites, nature of data to be expected, and feasibility of interpretation of observations into fundamental data.

(c) Competence. An assessment of competence of persons and agencies making pro­posals was attempted. The principal foundation for such assessment was previous record of achievement in work of the general nature proposed.

(d) Importance of a Satellite Vehicle to Proposed Work. The nature of each proposal was analyzed with respect to the questions: Is a satellite essential or very strongly desirable as a vehicle for the observing equipment proposed? Or could the observations be made nearly as well or better with balloons or conventional rockets as vehicles?41

Van Allen’s Geiger-Muller (GM) counter cosmic ray proposal was accepted on 12 May 1956 by the U. S. National Committee for the 1957-1958 IGY (see the comments in the foreword). It was placed on the short list of potential payloads for early satellite missions, and initial funding was arranged.

At its second full meeting on 1 June 1956, the WGII produced an initial constel­lation of priority-ordered Earth Satellite Proposals (ESPs) out of those that had been submitted. They were as follows:

ESP-8, Satellite Environmental Measurements, H. E. LaGow, Naval Research Laboratory.

ESP-9, Solar Lyman-Alpha Intensity, H. Friedman, Naval Research Laboratory.

ESP-11, Proposal for Cosmic Ray Observations in Earth Satellites, J. A. Van Allen, University of Iowa.

ESP-4, Proposal for the Measurement of Interplanetary Matter from the Earth Satellite,

M. Dubin, Air Force Cambridge Research Center.42

At a meeting in early December 1956, the WGII converted that list into a somewhat modified group in which some of the initial proposals were combined and several others were added. The complete list included studies in meteorology, geomagnetism, ionospheric physics, cosmic rays, meteorites, and astrophysics. They identified that list as a “hard-core program” of onboard experiments, designated them as priority-A experiments, and set the stage for their funding.

The first priority-A package included the instrument proposed by Herbert Friedman of the NRL to monitor the intensity of the solar Lyman-alpha ultraviolet emission line at 1215.7 angstroms. It employed a straightforward ionization chamber covering the range 1100 to 1400 angstroms. That primary experiment was to be accompanied by a group of measurements to determine the effectiveness of the provisions for controlling the temperature within the satellite and to measure the density of the field of micrometeorites and their effect on the outer satellite surface.

Unsuccessful attempts were made to launch that instrument on 28 April 1958 (Vanguard TV-5), 27 May 1958 (Vanguard SLV-1), and 26 June 1958 (Vanguard

CHAPTER 3 • THE INTERNATIONAL GEOPHYSICAL YEAR 83

SLV-2). That set of instruments was ultimately launched on 18 September 1959 as part of a substantially expanded Vanguard III payload.

The second approved package included Van Allen’s cosmic ray instrument, con­sisting of a single GM counter coupled with onboard data storage to provide coverage over the entire geographic area covered by the satellite. The observation of cosmic ray intensity above the atmosphere was expected to reveal the geographical symmetry of the cosmic ray intensity, and the deviations of that symmetry from that of the Earth’s magnetic field. The instrument was also expected to provide a first measurement of fluctuations in the intensity of the primary cosmic rays in order to study their possi­ble sources and the process by which they reached the Earth. It was envisioned that the satellite information would supplement and extend the ground-based cosmic ray observations also being planned for the IGY. A second instrument on that package was a set of sensitive gauges on the outer skin of the satellite for determining the order of magnitude of erosion due to meteoric impacts. That instrument was proposed by Edward Manring and his group at the Air Force Cambridge Research Center in Massachusetts.

The development of the second Vanguard experiment package is the primary subject of Chapter 5.

The third priority-A package consisted of a proton precessional magnetometer to measure the Earth’s magnetic field at high altitudes and over an extended geographical area. The basic instrument, in a 13-inch diameter sphere, was reduced to flight form under James P. Heppner’s leadership at NRL. That third payload also included a 30 inch diameter inflatable sphere proposed by William J. O’Sullivan at the National Advisory Committee for Aeronautics laboratory at Langley Field, Virginia. That sphere was to be separated from the primary satellite and tracked from the ground to provide a sensitive measurement of the density of the Earth’s atmosphere at much greater heights than hitherto possible.

An unsuccessful attempt was made to launch that two-instrument package on 13 April 1959 (SLV-5). The magnetometer flew later as part of the instrument com­plement on the expanded Vanguard III on 18 September 1959. The inflatable sphere was never flown successfully in that form. A somewhat similar sphere, focused on the original objectives, was eventually launched on 16 February 1961 as Explorer 9. Two Echo satellites, launched on 12 August 1960 and 25 January 1964, used technology developed in that program.

The fourth Vanguard launch vehicle was reserved for a meteorological experiment. Two packages were developed, of which one was to be selected for flight. The first instrument was for the observation of cloud cover over a substantial portion of the Earth’s surface. Developed by William G. Stroud, William Nordberg, and their group at the U. S. Army Corps Signal Engineering Laboratories at Fort Monmouth, New Jersey, it employed two photoelectric telescopes to scan the Earth’s surface as the

OPENING SPACE RESEARCH

Подпись:satellite spun, coupled with an onboard tape recorder for data storage over the entire orbit.

An unsuccessful attempt was made to launch that package on 26 September 1958 (Vanguard SLV-3), and it was successfully orbited on 17 February 1959 as Vanguard II. Unfortunately, its scientific value was limited due to an unplanned wobble in the satellite’s spin due to tipoff by the final rocket stage.

The other meteorological experiment was developed by Verner E. Suomi, engineer Robert (Bob) Parent, and their group at the University of Wisconsin. It employed four specially prepared small spheres supported by rods around the outer equator of the satellite. Those sensors were sensitive to radiation at several different wavelengths to provide a measure of the Earth’s radiation balance, i. e., the net effect of radiation arriving from the Sun and of radiation being emitted from the Earth.

An unsuccessful attempt was made to launch the Wisconsin instrument on 22 June 1959 (Vanguard SLV-6). Although that instrument was never successfully launched as a part of the Vanguard program, it was adapted for the Explorer 7 payload that was successfully launched on 13 October 1959.

Six backup experiments were designated by the WGII, in case problems arose with the development of the primary instruments described above. Those packages were never assigned flight space as part of the Vanguard program, although many of their objectives were ultimately achieved by instruments in different forms on later spacecraft.

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