Category Dreams, Technology, and Scientific Discovery

that demanded substantially higher levels of mathematics and abstraction.3 Many new students quickly entered those newly highlighted fields, and postgraduation job opportunities seemed nearly unlimited. The goal of human landings on the Moon was soon reached, pride and enthusiasm ran high, scientists and engineers exulted in high public esteem, and young people clamored for a chance to join in the excitement and challenge.

Since then, the enthusiasm for space exploration has substantially ebbed, as public attention became increasingly redirected to the civil rights movement, the Vietnam War, and a growing concern about our environment. At least to some extent, ma­terialism and commercialism have replaced some of the sense of adventure that accompanied the early foray into space. The almost worshipful public regard for sci­entists and engineers diminished as a growing realization developed that science and technology could not solve all of society’s ills.

Fewer physics students are entering our universities today. The building of the International Space Station has not engendered the kind of widespread public excite­ment that accompanied the “race to the Moon.” Yet the fascination with “reaching out” to discover our physical surroundings continues to capture substantial public interest.

Humankind’s development from its primitive beginnings has progressed through a remarkably small number of truly defining events. The development of language and the resulting expanding social consciousness contributed to the realization that there were opportunities beyond the basic survival needs of each individual. In the same way that individuals began to look outside themselves, the Greeks, Near Easterners, Nicolaus Copernicus, and others questioned the concept that the Earth and its human inhabitants were the center of the universe. Charles Robert Darwin and, simultane­ously, Alfred Russel Wallace effectively publicized their beliefs that living things on the Earth developed over a long period by a series of very small evolutionary steps.

There has been a long-standing and deep-seated belief that Earth is unique within the universe as being the only home for life—that is, substance with the ability to reproduce. Although we may eventually find that to be true, with the knowledge being accumulated today, that belief is being challenged. There is a growing realization that life just possibly might have developed in other star systems and galaxies as well as on Earth.

The first conclusive discovery of life in any form anywhere else than on Earth will rank in importance with the major defining events mentioned above. Even though it is highly unlikely that life will have evolved elsewhere in the same way that it has on Earth, the discovery of individual living cells of any kind will bring about another

OPENING SPACE RESEARCH

fundamental and pervasive change in our thinking about humankind’s place in the scheme of things.

The first 50 years in space, in spite of its remarkable accomplishments, has opened only a small window to a greater understanding of our remarkable universe, and to a greatly increased awareness of humankind’s place in it.

[1] made a side trip while on the East Coast. Significant satellite-related design work was under way at the Signal Corps Engineering Laboratories at Fort Monmouth, New Jersey, and I went there to learn about it. I learned of their work on developing state-of-the-art power sources and transistor power converters.

That work looked so promising that I returned two months later for further discus­sions. Their engineers gave me a general briefing on primary power sources that might be used in our package, including silver-zinc, silver-cadmium, nickel-cadmium, solid electrolyte, nuclear, and solar cell sources. We also discussed their work on transistor power converters at considerable length, and they gave me a copy of a report that summarized their development efforts.22 Those discussions and that report gave me

[2] was dealing with another difficult issue during the week of 28 October. Everyone agreed that my presence would be needed at JPL if we were to prepare the two instrument packages in the short time available. Eb Rechtin suggested that JPL could hire me and move my family to Pasadena for the duration. The terms seemed reasonable. I felt truly crippled, however, because of Van Allen’s absence. He and I had no opportunity to discuss the many important practical matters and long-term implications of such a move. Ernie Ray, as acting department head, did not believe that he had the authority to approve my remaining a University of Iowa employee, in residence at JPL.

[3] was especially anxious to arrive home to see how my very pregnant wife was pro­gressing. I was greatly relieved to find that Rosalie’s father, the Reverend Loyal H. Vickers, had been staying with her. He stayed on for some time and pro­vided wonderful physical and moral assistance as Rosalie struggled to maintain the house and oversee the two children while I was so completely occupied at the laboratory.

Two days after my return, as her dad watched the children, Rosalie and I went out with one of her uncles and his wife for a special evening of relaxation and entertainment. We had wanted to see the famous Hollywood Boulevard and Vine Street intersection that marked the center of the motion picture industry at that time. After seeing the imprints of notable movie stars in the sidewalk, we went to dinner, and then to the Cinerama showing of Seven Wonders of the World. After the show, we stopped for coffee at a shop on the very corner of the famous intersection, and one of those highly improbable coincidences in life occurred.

We had no longer sat down in our booth than we were confronted by a very excited man from a neighboring table. It turned out that he had just spent much of his afternoon

[4] remember little of the 1957 Christmas holidays in the blur of the satellite work. Rosalie was in her third trimester of pregnancy. Fortunately, her parents visited us for a substantial interval that included Christmas. Their presence provided much needed help and interaction for Rosalie in the middle of her efforts to carry so many of the household and family responsibilities. We had our usual family celebration on Christmas Day. On New Year’s Day, Rosalie and I watched the Rose Bowl Parade on television. Although we were living less than a mile from the parade route, we decided to relax at home and not brave the crowds.

The designations, GM counter identification numbers, and dispositions of the four payloads were as shown in Table 10.1.

We had only two weeks to prepare the payloads for the new launch attempt. We immediately tackled the tape recorder difficulties that had been encountered during the Deal IIa Cape activities. I canceled my plans to go to the ABMA in Alabama that Thursday for work on a new IGY Heavy Payload being proposed, so that I could help with the Deal IIb instruments. Discussion of that new project is detailed in Chapter 14.

[6] discovered that the double-stepping that we had encountered with the Deal IIa tape recorder was due to overtravel of the tape-advance solenoid, and stops on the remaining recorders were adjusted to prevent a recurrence. We also spent consider­able time in fine-tuning other adjustments in the recorders to ensure more reliable operation.

As for the launch pad difficulties in interrogating the Deal IIa tape recorder, JPL engineers made many tests and analyses of the radio frequency system. These included two specific tests related to possible causes for loss of command receiver sensitivity.12 One was that the antenna radiation pattern might have been distorted. That effect was simulated and eliminated from further consideration. The second possibility was that receiver sensitivity might have been too low, at least partly a by-product of electrical noise generated by the spin motor for the upper-stage tub. That condition was also simulated, with the conclusion that it, in fact, might have been a factor. The command receiver sensitivity was increased, and other arrangements were made at the Cape for increasing the signal-to-noise ratio for the interrogation signal in the neighborhood of the launch gantry.

Several new problems surfaced during the second half of the week of 10 March. A resistor on deck “G” of the Environmental Test Payload IV failed and had to be replaced. That meant unwiring and removing that particular electronics deck from the instrument stack, digging through the foam encapsulation, replacing the resistor, recasting the foam, retesting the deck, reinstalling it in the stack and rewiring it, and

[7] There were no problems with the Explorer I primary mechanical structure or of its provisions for controlling its internal temperatures.

• Throughout the satellite’s operating lifetime, the performance of the State Uni­versity of Iowa (SUI)-designed scientific instrument consisting of the Geiger – Muller (GM) counter, its 700 volt power supply, and the binary scaling circuits was faultless.

• The low-power transmitter subsystem, including its associated subcarrier oscilla­tors, operated perfectly until the normal exhaustion of its batteries. That occurred on 13-14 April 1958, after two and a half months of continuous operation. Its design lifetime had been two months.

• The high-power transmitter and its associated subcarrier oscillators operated perfectly until the morning of 12 February. Its signal faded away gradually during the next day, with a last detectable but weak signal at 11:15 UT. That operating lifetime of nearly 12 days is only two days short of the system’s design lifetime of two weeks.

[8] High-Power System

о From 1 through 11 February, there was an average of 22 recordings per day. Once routine operations were established after the initial day, and un­til 8 February, the numbers varied in an essentially random pattern from 21 to 29 passes per day. During 9, 10, and 11 February, the rates were some­what lower, at 18-19 passes per day. That reduction was probably due to a small decrease in the transmitter output power due to decreasing battery voltage, combined with changes in orbital positions relative to the receiving stations.

о During the period from 24 through 27 February, that is, while the high – power transmitter was again sporadically operating, the recovery rate was much lower, at 4.8 passes per day. There were several reasons for that lower rate. Even though some of the Minitrack high-power signal receivers

[9] NRL Minitrack stations at Santiago, Chile; Antofagasta, Chile; Quito, Ecuador;

Havana, Cuba; Fort Stewart, Georgia; and Woomera, Australia

[10] remained at Cape Canaveral for about a week after the Explorer IV launch to begin preliminary preparations for the next attempt. Everyone wanted a second instrument in orbit before the nuclear detonations to provide the greatest probability of adequate coverage.

From 4 through 8 August, our family had a pleasant drive together in returning to Iowa City. Our laboratory was occupied with many last-minute preparations for data analysis and for the next launch. Pickering arrived on 9 August to discuss data reception, reduction, and dissemination. We increased the amount of lead shielding on one GM counter and put a small calibration source in one scintillation detector for that second launch.

On 13 and 14 August, it was back to Huntsville, and then to Cape Canaveral for final launch preparations. A countdown was started on 21 August but was canceled due to a leaky fuel valve on the booster rocket. On 22 August, there began a last – minute scramble to repair a problem in one of the spare flight payloads, so that there would be sufficient spares on hand to cover any eventuality. The next day, I took that spare to Huntsville for a vacuum test and returned it to Cape Canaveral. Meanwhile,

[11] received one year’s undergraduate credit for training that I had received in the Air Force—thus, I started in February 1953 with sophomore status. I took full 16 semester-hour loads the first three regular semesters but dropped back to 12 hour loads for the rest of my undergraduate studies because of my increasing workload in the Cosmic Ray Laboratory. In spite of that, by adding summer sessions in 1953 and 1955, I earned my B. A. degree in three calendar years, receiving it at the 14 February 1956 commencement ceremony.

My undergraduate years were very enjoyable. Although extremely busy, both my academic studies and the work in the laboratory were exciting, challenging, and rewarding. It was as though I had been preparing all my life for that situation. My teenage interest in electronics, my communications and radar training in the Air Force, and the broadening effect of widespread travel, officer training, piloting, and management in the Air Force all served to prepare me for the new environment.

As I neared the end of my undergraduate work, I struggled with an important question. I felt that I should broaden my experience by going to a different school for my graduate studies. I began looking for another situation where I could attend college and also find acceptable work to help support my family. My most sub­stantive effort in that regard was an inquiry in March 1956 to the Missile Systems Division of the Lockheed Aircraft Corporation in California about their Advanced

As already mentioned, the most significant single new result from the early rockoon flights was the discovery and early characterization of the auroral soft radiation. That discovery was completely unexpected and turned out to have important impli­cations.

Following the initial detection of the extra radiation during two rockoon flights during the summer of 1953, Meredith, Gottlieb, and Van Allen tentatively hypothe­sized that the GM counters had registered the high-energy tail of the primary auroral particles.36 They stated that the observed particles were most likely electrons having energies in the neighborhood of 1 MeV that were directly penetrating the residual atmosphere above the rocket, the sheet metal of the nose cone, and the wall of the GM counter. They eliminated protons as the cause by reasoning that, if the particles were protons, then they must have possessed energies up to 35 MeV and beyond in order to penetrate the various absorbing materials. They then pointed out that protons of that energy would have too large a radius of curvature as they spiraled around lines of the Earth’s magnetic field to produce the observed spatial inhomogeneity. They also stated that the observed energy spectrum was low enough that most of the particles could not be coming along Stormer-type trajectories directly from external sources such as the Sun.

The auroral soft radiation was seen again during three of the summer 1954 rockoon flights. Two flights of the first type of instrument containing paired GM counters with different absorber thickness had been ballistically successful, and the second one dramatically revealed the auroral soft radiation superimposed on the primary cosmic ray background. Based on those data, Ellis, Gottlieb, and Meredith reported in an abstract in July 1955 that the ratio of counting rate for the counter without the absorber to the rate for the counter with the added absorber was about three for the

CHAPTER 2 • THE EARLY YEARS 55

upper part of the flight (55 to 60 miles). It was about two lower in the flight where the radiation was first encountered.37

Data from the flights of the second instrument type containing McDonald’s new scintillation detector-GM counter instruments were somewhat confusing.38 That con­fusion was partly resolved by the summer of 1955, when McDonald, Ellis, and Gottlieb published an abstract stating that, of three successful flights of that instrument, two revealed the soft radiation.39 It was seen as an elevated counting rate in the single GM counter mounted ahead of the scintillation detector. They concluded that the radiation had not been energetic enough to activate the telescope by traversing the combined absorbing materials ahead of and in the instrument. Those abstracts of the preliminary analyses did not offer further speculation about the particle species.

Van Allen also published a brief abstract at that time, in which he stated that the average density of material penetrated by the particles was of the order of 180 milli­grams per square centimeter in aluminum and 220 mg/cm2 in the atmosphere.40 He alluded to possible interpretations in terms of gamma rays having energies of about 20 KeV, electrons of energy about 1 MeV, or protons of energy about 15 MeV. Thus, although the possibility that the detectors were directly detecting elec­trons had not yet been entirely discounted, other possibilities were being seriously considered.

The situation was finally resolved following analysis of the aggregate of all rockoon data following completion of our 1955 expedition. The results were promptly reported at the spring 1956 meeting of the American Physical Society.4142 Van Allen and Joe Kasper’s summary paper asserted that (1) the auroral primary radiation consisted of electrons with energies of the order of tens of KeV and (2) the GM counters were actually registering X-rays (referred to as bremsstrahlung, or braking radiation) produced in the nose cone by bombardment by the electrons.

Those early assessments were expanded upon and summarized by Van Allen in a classic paper published in early 1957 by the National Academy of Sciences. He summarized the salient features of the radiation:

a) The latitude distribution and the temporal variability of the effect [the soft radiation] strongly suggest that it is to be associated with aurorae.

b) The radiation is quite soft (by cosmic ray standards), being completely or nearly completely absorbed… by amounts of material ranging from several gm/cm2 to several hundred mg/cm2 of air and/or aluminum and being attenuated by a factor ranging from 3 to greater than 50 by 150 mg/cm2 of lead.

c) Referring to the crystal measurements which give absolute energies dissipated in the crystal, we have observed no case in which resolved pulses corresponding to greater than 200 keV occur (except for the expected number of cosmic ray pulses), even though there is a simultaneous occurrence of a very large counting rate in the more heavily shielded Geiger tubes. . .

d) The “wings” of the counting rate versus time curves are in all cases “regular” in character and are believed attributable to atmospheric absorption.43

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In that paper, Van reaffirmed the conclusion that the detectors could not have been directly registering protons or electrons. He further asserted that X-rays having energies in the range 10-100 keV were consistent with all observed data. He provided an estimate that the X-ray intensity was of the order of magnitude 103-105 photons per square centimeter per second. It was believed that the X-rays seen at relatively low altitudes (25-45 miles) were bremsstrahlung from electrons that were stopped at 55 miles or above in the atmosphere, and that when the rockets were at higher altitudes (say, above 65 miles), the primary auroral electrons were striking the walls of the apparatus and creating the bremsstrahlung locally.

The locations of ships at the times of launching all of the 55 rockoon flights during the 1952, 1953, 1954, and 1955 expeditions are indicated in Figure 2.14. The flights clustered near Thule, Greenland, were made during the 1952 expedition when the rockoon technique was being initially tested. The flights extending from Boston, up the Nova Scotia coast, and around Newfoundland were largely shake­down flights, although several were fully successful and yielded data for the latitude survey, the original program objective. The rest of the flights, those off the coast of Labrador, up Davis Strait, and across Baffin Bay, represent attempts either to obtain data points for the latitude survey or to investigate the auroral soft radiation after it was initially discovered in 1953. The initial discovery of the soft radiation by SUI flight 13 on 28 July 1953 is indicated by the star located just north of Resolution Island.44

Van Allen summarized the results of many of those flights in another form in a figure in his 1957 paper, reproduced here as Figure 2.15.45 In this figure, the peak counting rates from the 10 flights represented by the stars in Figure 2.14 are plotted as a function of geomagnetic latitude.

The peak occurrence of visible auroras occurs near the center of the shaded region in Figure 2.14, and near the 68 degree geomagnetic latitude region in Figure 2.15. Taken together, these two figures dramatically illustrate the close association of the auroral soft radiation observations with the visible aurorae. Those results constituted the first in situ detection and measurements of the presence and composition of the radiation responsible for the visible aurorae. Further rockoon observations by Van Allen and colleagues during 1957 (described in Chapter 4) helped to further define the characteristics of that phenomenon.46

Had more been known about magnetospheric physics in 1956-1957, the Iowa group might have deduced that some substantial portion of the X-rays were being produced by charged particles mirroring in the northern cusp of the later-discovered outer region of high-intensity trapped radiation. Postulation that huge populations of charged particles were durably trapped in the Earth’s magnetic field was not made, however, until after the initial Explorer I and III data were examined in 1958.

CHAPTER 2 • THE EARLY YEARS

FIGURE 2.14 The approximate locations of all rockoon flights during the 1952,1953,1954, and 1955 expeditions are indicated by circles (unsuccessful), plus signs (instruments reached a height of 120 miles or more but did not observe the auroral soft radiation), and stars (instruments reached a height of 120 miles or more and detected the auroral radiation). The shaded oval indicates the approximate location of the region where visible auroras are most frequently seen.

Anderson’s Canadian balloon flights in early 1956

Kinsey Anderson became another highly productive member of the Iowa cosmic ray group when he joined it in the fall of 1955.

OPENING SPACE RESEARCH

Kinsey A. Anderson

Kinsey A. Anderson was bom on 18 September 1926 at Preston, Minnesota, and grew up there. He received his B. S. degree in physics from Carleton College in 1949, and went on to the University of Minnesota, where he received his Ph. D. degree after the spring semester in 1955. He stayed on there for the summer as a research associate to work with John Winckler and colleagues on a survey of cosmic ray intensity over the range 51 degrees to 65 degrees north geomagnetic latitude, using a triple-coincidence Geiger counter lofted by small latex balloons.

During Kinsey’s work that summer, one of their balloon flights, made from Flin Flon, Manitoba, on 26 August 1955, at a geomagnetic latitude of 65 degrees, revealed a dramatic increase in the counting rate of their counter telescope. This was quite unlike anything they had seen during the earlier, more southerly flights. They were aware of the discovery and study by our Iowa group of the auroral soft radiation during the 1953 and 1954 rockoon expeditions, and of the further studies being conducted during the 1955 expedition. Kinsey and Winckler were fully aware that we were beginning to think seriously about X-rays as the possible cause of the anomalous high counting rates at the rockoon altitudes. But they could not understand how X-rays might penetrate to the lower balloon altitude to produce the result they had seen. This mystery served as a major motivation for Kinsey’s later research program at Iowa.

Kinsey joined the Iowa Physics Department in September 1955 as a research associate, advancing to assistant professor in 1958. He left Iowa City in November 1959, spending the next several months at the Royal Institute of Technology in Stockholm, Sweden. He moved to the University of California at Berkeley (UCB) in the autumn of 1960 to join the space research program there. During a long and distinguished career at UCB, he advanced to full

CHAPTER 2 • THE EARLY YEARS 59

professor in 1966, contributed substantially to the U. S. space research program, and served as director of the Space Science Laboratory for many years. He is currently a Research Physicist Professor Emeritus at Berkeley.

Kinsey’s initial undertaking at Iowa was to continue the theme of his Minnesota research, but with the use of larger Skyhook balloons. His first instrument, a GM counter telescope for measuring cosmic ray protons and helium nuclei, was ready by early 1956. He carried his flight instruments to Goodfellow AFB as the sole Iowa participant on a third ONR-sponsored field exercise.47

Experimenters from other laboratories on that Goodfellow expedition were from the universities of Chicago and Minnesota. An ONR field representative, R. C. Cochran, was in overall charge, and General Mills again handled the balloons. Notices were placed on all flight packages to facilitate their quick recovery but, acting on previous experience, in this case, advance notices were also sent to Texas ranchers and cattlemen so they could be on the lookout for equipment landing in their areas.

That expedition saw the launch of 10 balloon flights between 25 January and 15 February 1956, several of which carried Kinsey’s instruments.48

Even though there was tremendous excitement about the Soviet Sputnik announce­ment at the conference, I still had a work session scheduled at NRL. Their engineers and I pushed ahead resolutely to complete that work, beginning immediately following the conference closure at noon on Saturday, 5 October.

The first order of business was to test and calibrate the radio frequency portions of the complete system, both the satellite portions independently, and then with the ground receiving and transmitting equipment. Martin (Marty) J. Votaw and Roger Easton, the Vanguard senior engineers for those components, made the measurements and adjusted the design as needed. For that purpose, we mounted the instrument package in the NRL prototype satellite shell. Final tailoring of the wiring harness to the antennas adjusted the phasing of the signals to produce the correct antenna radiation pattern. Those tests also revealed the need for an additional radio frequency shield between the receiver and transmitter circuit decks. After several days of fitting and tuning, our measurements showed that the telemetry transmitter, command receiver, antennas, and interconnecting harness were all operating properly as a system.

Next, we began tests to check the performance of the satellite while it was operating in concert with the prototype ground station. Runs with varying amounts of signal attenuation gave us confidence that the space and ground components should operate together over an orbit-to-ground range of up to several thousand miles.

As a final test, we had planned to fly the instrument package via helicopter over the first operational Minitrack receiving station located on the shore of the Chesapeake Bay at Blossom Point, Maryland. Delays in getting the Blossom Point station fully operational, compounded by their scramble to modify the station to receive the signal from the newly launched Soviet satellite, forced a postponement. In spite of the incomplete testing, we did develop reasonable confidence that the space-to-ground link would perform as intended.

The radio frequency tests were to be followed by a (it was hoped final) set of design-level vibration and acceleration tests. However, those tests, planned for 9 and 10 October, could not be undertaken on schedule due to breakdowns in the test equipment, and they were rescheduled for a later time.

Before they could be run, our instrument was shifted to the army’s Jupiter C program.

OPENING SPACE RESEARCH

I finally returned to Iowa City on Wednesday, 16 October, 12 days after the Sputnik launch. During the rest of October, I scrambled to try to catch up with my university course work and to attend to a few lingering details of the electronic circuit design and package fabrication. My laboratory notebook entry for 29 October stated quite simply, “Completed test unit.”28 Although a slight overstatement, that point did mark the end of all work on the Vanguard version of the instrument, and my full attention shifted to adapting the instrument to the Army’s Jupiter C vehicle.

A final progress report to our granting agency in October listed a few minor items to be completed and mentioned that the first of the magnesium satellite shells was due to be delivered by the fabricator to NRL in November.29 That final report also listed the instrument package weight as just under 13.0 pounds, which, when added to the weight of the satellite structure and other components, made the total satellite weight two to three ounces less than the 21.5 pounds that had been allocated.

Although the Sputnik launch energized Wernher von Braun, Bill Pickering, some of the Army brass, their disciples, and many others throughout the United States, Pres­ident Eisenhower at first remained tranquil. During the days immediately following the launch, he downplayed the event’s importance. On 9 October, he sang that tune with gusto when he told newsmen at a press conference that “the effect of Sputnik does not raise my apprehension, not one iota.”3

That attempt to downplay the significance of the Soviet Sputnik failed to sway the press, and their editorials quickly became loud and critical. With the Sputnik launch,

CHAPTER 8 • GO! JUPITER C, JUNO, AND DEAL I 215

the Soviets convincingly demonstrated that they could deliver atomic weapons over great distances long before the United States had that capability. They were, in both fact and popular perception, well ahead of us in brute force long-range missilery.

Two days after the satellite launch, Russia announced that they had exploded a “powerful hydrogen device of new design” at a very high altitude. The combination of the satellite launch and their successful weapons test served to embolden the So­viets, and the tempo of their saber rattling increased markedly. Premier Khrushchev sent letters to members of NATO threatening them with H-bomb destruction, deliv­ered via long-range ballistic missiles, if they allowed any American missile bases to be established on their territory. Indications of Soviet intent to attack Turkey intensified. The Soviets even threatened the United States with missile retaliation if we interfered directly in the struggle between Lebanon and the United Arab Republic.

That situation was not eased when the Soviets launched a second satellite only a month after their first launch. Sputnik 2, weighing an incredible 1121 pounds and carrying a live dog, was launched on 3 November 1957. It triggered a flood of further criticism of the Eisenhower administration. He and his officials were faulted for letting the Soviets surge ahead of the United States in rocketry and, by straightforward extension, the broad areas of technology and science. The American public, egged on by a raucous press, embarked on a binge of critical self-analysis. All of a sudden, many things Russian, including their educational system, were viewed as superior to the U. S. equivalents.

A few days after the second Sputnik launch, acting under public pressure, Eisen­hower finally knuckled under. He gave Secretary of Defense McElroy authorization to proceed with the Army’s plan. The press promptly reported that the Army had been instructed “to proceed with the launching of an Earth Satellite, using a modified Jupiter C.”4

As a side note, criticism at that time of President Eisenhower’s reluctance to increase the priority of a satellite launch has softened over the intervening years, as the true state of overall Soviet technological prowess in the 1950s has become better understood. In the totalitarian state that existed then, the Soviets were able to commit immense resources on a selected few projects. The choice of those projects was based on military and propaganda value rather than any consideration of direct benefits to Soviet society or scientific aspirations.

Thus, the Soviets were able to pull off a whole series of space spectaculars ahead of the United States for awhile, including being first in space, first to launch a live animal, first to the neighborhood of the Moon, first to impact the Moon, first to take pictures of the backside of the Moon, first human in orbit, and first to orbit two astronauts in a single spacecraft. They did that by learning of our intentions and mounting crash

OPENING SPACE RESEARCH

programs behind their curtain of secrecy to beat us. Eventually, however, the ability of the United States to sustain a long-term high technology program won the race to place humans on the Moon. Since then, the United States has dominated the scene in both the scientific and manned space arenas.

Because of his access to believable, highly secret intelligence information, Eisen­hower was convinced even in 1957 that the Soviets actually lagged the United States in overall technical prowess. His primary error was in underestimating the propaganda value of the first achievements in space.5 6

Although news of the oral instructions to proceed with the Army program resulted in initial rejoicing in Huntsville, that was cut short when the official written directive was received the next day. It stated that the Army was to proceed with “preparations” for a launch. Calls by General Medaris confirmed that the order withheld authority to actually launch. It seemed that the thinking in Washington was to give the actual launch authority only if the Vanguard program continued to falter. If the Vanguard program became productive, the Army would be instructed, in effect, to “put their toy on the shelf.”

At that point, an irate General Medaris dictated a wire to the Army’s research and development chief, General James M. Gavin, threatening to quit if ABMA did not receive a clear-cut order to launch. Both von Braun and Pickering were in the office with him as he prepared that wire, and they insisted that Medaris include their similar sentiments.

It was only then that the Army brass in Washington issued a clear authorization for the launch. That occurred on Friday, 8 November 1957.

I left Cape Canaveral on 7 March for a one day stop in Iowa City, where our small cosmic ray group met to discuss the data arriving from Explorer I. That discus­sion is described in the next chapter. On Sunday, I boarded a plane again, bound for Pasadena to help prepare for a second attempt to launch our full cosmic ray instrument.

The first order of business upon arriving in Pasadena was to check on Rosalie, whose time for delivery of our third child was fast approaching. I had been away from 20 February until 9 March—a long two and a half weeks considering that son George made his appearance into the world only nine days after my return.

On Monday, it was back to the laboratory. All parties understood that a second Deal II launch attempt would be made as quickly as possible. We set about with great urgency to prepare for that attempt.

If one includes the original Environmental Test article, four Deal II satellite pay­loads were built. The Environmental Test model would not normally have been con­sidered for flight, after being intentionally overstressed during its testing regime. But we wanted to have three units in the best possible working condition at the Cape, in case we should have unexpected problems and need the additional hardware. There­fore, our launch preparations included that payload, as well as the two primary flight units.

The next two days, 11 and 12 March, Van Allen visited the JPL for a special meeting. Although discussion of preliminary results from the Explorer I data was billed as the purpose of the meeting, its actual primary purpose was a thinly veiled discussion of a highly classified topic of immense importance. The attendees, in addition to Van Allen and me, included Bill Pickering, Jack Froehlich, and Henry Richter of JPL, Major General John Mederas from Huntsville, and several others, most interestingly, Stanford University’s Wolfgang K. H. Panofsky, who was heavily involved in the U. S. atomic bomb testing program. That story is resumed later in this chapter and in Chapter 13.

The information discussed at that meeting lent additional urgency to the early analysis of the Explorer data and marked the beginning of planning for a new satellite, which was launched a few months later as Explorer IV.

From the time of the decision to launch a backup Deal II satellite, the failed mission was referred to within JPL and ABMA as Deal IIa, and the new attempt was dubbed Deal IIb. For some reason that I never understood, the JPL payload manager changed the payload identifications for that second attempt, leading to considerable confusion.

CHAPTER 10 • DEAL II AND EXPLORERS II AND III 277 [5] [6]

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then retesting the entire payload. During that retesting, the transmitter power output dropped for a while on one occasion. But it returned to its normal level before the engineers could determine what was wrong, and it never recurred. Thus, Payload IV had a possible not-understood incipient failure, a long history of various difficulties, and thus could not be depended upon for use as a full spare payload. It was taken to the Cape, nevertheless, as an emergency source for parts, if they should be needed.

A substantial change was made in one of the two satellite antennas on all three units. Explorer I had employed a so-called “turnstile” antenna for the high-power transmitter. One of its four stainless steel cable elements appeared to have broken off immediately after final injection, as described in Chapter 11. The significance of the change in the radio frequency radiation pattern following the Explorer I launch had not been fully understood by the time Deal IIa was launched, so that payload had retained the original whip antenna.

The situation was better understood by mid-March, however, and the JPL engineers undertook a crash program to change the antenna for the high-power transmitter and command receiver to eliminate the whips. It was converted to a simple linearly polarized dipole antenna, in which the shell of the instrument payload and the rocket casing served as the two driven elements. That change was designed, fabricated, tested, and installed by the JPL engineers on all three Deal IIb payloads during the short time available.

As in the case of the Deal I calibration data, JPL assembled a set of complete calibration data for the Deal IIb/Explorer III flight counter.13

Our baby was due any time after Friday, 14 March. As Barbara and Sharon had been born very quickly after the beginning of Rosalie’s labor, and since we lived a considerable distance from the hospital, she and I were very concerned about getting her there in time for her third delivery. We worked out what we considered the best route from our home in north Pasadena to Behrens Memorial Hospital in Glendale. That was in a time before interstate highways. The routes via the Pasadena and Los Angeles freeways took a long path around the San Rafael Hills, and they were frequently and unpredictably greatly congested. So we chose a route across the hills via Linda Vista and Chevy Chase drives. Our test drive on that Sunday afternoon revealed that those roads were very curvy but unlikely to be congested.

Our third child arrived two days later, on Tuesday, 18 March 1958. The day turned out to be rather complicated! At 1:00 in the early morning, Rosalie informed me that her labor pains were five minutes apart, so I loaded her and the two girls into the Mercury and we made our tortuous trip to the hospital. It soon became evident that her pains were false labor, so I took Barbara and Sharon home so they could get more rest in their own beds. After we arose that morning, we returned to the hospital, where we learned that Rosalie’s labor was not progressing.

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Noticing how uneasy I was, being preoccupied by the pressing work awaiting me at the laboratory, she suggested that I take the girls back home and go to my office. We had struck up a close personal friendship with Bill Pilkington and his family. The young couple had offered to take care of the two girls while Rosalie was in the hospital, so I dropped them off there and returned to the laboratory.

Rosalie and I maintained contact with the Pilkingtons after our return to Iowa, but to our great horror and dismay, the entire Pilkington family, parents and children, were killed some time later when their private airplane crashed in Mexico.

In the late afternoon, the staff at the hospital induced true labor, and our son was born at 7:24 PM. Once again, circumstances conspired to keep me from Rosalie’s side during our child’s actual birth (as turned out to be the case for all four of our children). My final notes for that day state, “He is a fine looking boy weighing seven and one-half pounds, 20 inches long, and with very little hair.”

We were delighted to have our first son and named him George Vickers Ludwig. The given name George continued a long-standing family tradition, honoring his father, grandfather, great-grandfather, and great-great-great-grandfather—all Georges. The middle name honored Rosalie’s family name.

Rosalie returned home from the hospital with our new son on Friday, 21 March. It seems unbelievable and somewhat embarrassing to me even today that I spent so little time with them during that period. I spent the next Saturday and Sunday mornings by beginning the design of a faster version of the binary scaling circuit for a future satellite. Thankfully, Rosalie’s mother arrived at our Pasadena home at that time to help during my continuing absences.

There was a substantial delay, sometimes exceeding three weeks, between the record­ing of data at the ground receiving stations and appearance of the data in our Iowa City laboratory. That was due, of course, to the time required for the shipment of data tapes from the widely spread sites, for clearing customs in some cases, for some limited processing and examination of the data at JPL, and for shipment of the tapes and charts from JPL to Iowa City. As of 5 February, the date on which I left Iowa City on my way back to Pasadena after the Explorer I launch, none of the Explorer I data had yet reached Iowa City for analysis.15

Even after the next week or two, only a sparse set of data was available. It consisted mostly of short segments (of the order of a minute each) from stations widely dispersed geographically. The positions of the satellite at the times when those bits and pieces were recorded were uncertain, as the accuracy of the satellite orbit computation in Washington was still evolving.

Even by the end of February, the situation remained quite tentative, as seen by examining an SUI progress report released on 28 February.16 Sanborn strip-charts from 74 passes over Microlock stations had been received from JPL. Of those passes, all but seven were from U. S. stations, that is, from locations where the satellite was near its northernmost excursion and not far above its lowest height, that is, outside the region of trapped radiation.

In addition to the Sanborn charts, magnetic tapes with copies of the appropriate channels from the ground station recordings had been received for 66 passes. In most cases, those were not the same passes as those for which the Sanborn charts had been received.

By 23 February (the cutoff date for the data analysis that was summarized in the 28 February progress report), SUI had examined, read, and plotted the data from 54 of those passes. Thirty-four (largely from stations in California, where the satellite

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was near its lowest altitude) produced clean and readable data. They showed cosmic ray counting rates within the expected range of 12 to 80 counts per second.

Although a substantial number of tapes from the Naval Research Laboratory’s (NRL’s) Minitrack stations had arrived at JPL by that time, none of them had been processed. Thus, none of the recordings made during deep excursions into the region of intense radiation were yet available.

The 28 February report did briefly mention a curious anomaly:

An apparently valid case of a temporal variation was observed in a record from the J. P.L. receiving station at 0123 UT on 2/5/58 [5 February]. An inadequate amount of data has been received to confirm the Japanese report of temporal variations at 0709 UT on 2/5/58 and at 0857 UT on 2/7/58. Reports of apparent temporal variations must be viewed with caution since the normal counting rate varies markedly with latitude and altitude.17

The complete tabulation of Explorer I data published much later reveals that the JPL pass mentioned here had shown a normal rate until about mid-pass, when it began edging upward, reaching 109 counts per second at the end of the pass. Thus, it was making a very shallow approach to the trapping region. Final analysis of the Tokyo passes revealed that the rate peaked at 324 counts per second and then decreased to a normal rate during the 5 February pass. The tabulations reveal that no data were received from Tokyo or any other station on 7 February at the time cited above. Thus, the one Tokyo pass did also indicate a mild incursion into the trapping region.

Records from Singapore and Nigeria deserve special comment. A later assessment revealed that the instrument had frequently risen well into the high-intensity radiation region over those stations during the 24 day period covered in the 28 February report. Such incursions occurred on 8 days at Singapore and on 14 days at Nigeria. However, no significant portion of those data had yet reached Iowa City by the time of the February report.

As a side note, the tapes mentioned above were just the beginning of the torrent of Explorer I data that eventually descended upon our laboratory. During just the period from launch through 23 February, a final total of 474 station recordings were of good enough quality that the beginning and ending times of radio frequency signal reception were eventually determined. Of those, 334 yielded at least short bursts of useful cosmic ray data. By the end of the satellite operational lifetime, the accumulated totals grew to 877 and 592, respectively.

In summary, the report on 28 February indicated satisfactory performance of the Explorer I instrument and included a few guarded comments about what were being referred to then as “temporal variations.” The general situation in Iowa City at the end of February can best be characterized as a mixture of jubilation that we were receiving useful data from the first U. S. satellite, frustration that we were not receiving

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the data more quickly, and perplexity about several mildly abnormal readings. The photograph on the cover is an accurate portrayal, even though staged sometime later, of the puzzling situation that existed at that time.

The first Deal II launch attempt was made on 5 March, but the satellite failed to enter orbit, as related earlier. I stopped at Iowa City over the 8-9 March weekend on my way back from the Cape to Pasadena. Our small cosmic ray group gathered in the physics building that Saturday to discuss the early Explorer I data. Van Allen, Ernie Ray, and I were joined by Carl McIlwain, who had recently returned from his Fort Churchill rocket-launching expedition and had just joined the Explorer I data effort. The three of them, with help from student data readers, had been trying to make sense of the unexpected “anomalous” readings.

The situation remained additionally clouded by the continuing lack of accurate orbital information, since minute-to-minute satellite orbital positions from the IGY Vanguard Processing Center had also not yet started to arrive. Joe Siry and his people in the Vanguard Computing Center in downtown Washington were working heroically but were still having difficulties in computing an accurate orbit, partly because the software and tracking system were new and had to go through a period of initial shakedown, but also because the orbit apogee was substantially higher than expected.

To further complicate the situation, both the tasks of interpreting the data and computing the orbit were complicated by the transition of the Explorer I motion from its initial axial spin to an end-to-end tumbling, as described in the previous chapter. The signals from both the high – and low-power satellite transmitters, although they were operating at their full design power levels, were very weak by any ordinary standards. The deep spin modulation that resulted from the change in the spin configuration resulted in additional dropouts in the data that complicated their interpretation.

Thus, even by the time of my 8 March visit, we still possessed only isolated segments of Explorer I data, mostly with durations of a minute or less. And the locations of the instrument in space where the data had been captured were uncertain.

Despite those factors, a discernable pattern was emerging. There were periods during which the counting rate was as expected from the primary cosmic rays, other periods during which the counting rate was much higher, and still other times during which the counting rate appeared to be zero. One especially intriguing case had been seen of a smooth transition during a station pass from a zero counting rate, to a high rate, and then to a normal cosmic ray rate.

My clear recollection of that 8 March meeting is of the four of us (Van Allen, Ray, McIlwain, and me) gathered around the conference table in Van’s office for an extended assessment of possible causes of the strange readings. The moment was later reposed and captured on film, and that photograph became the model for a 1962 painting by artist Robert Tabor that still hangs in Van Allen Hall at the University of Iowa.

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Either there was some systematic misbehavior of the instrument, or we were seeing a real physical phenomenon that was completely unexpected. We pored over every possibility we could think of to explain the anomalous rates. We debated, for example, whether the unusual observations could be the result of temperature effects on the GM counter or associated electronics. But there was no correlation between the anomalous rates and the passage of the satellite through the Earth’s nighttime shadow, where the instrument temperatures dropped to their lowest values. The only consistent correlation appeared to be with the satellite’s position relative to the Earth’s magnetic field. The high and zero apparent rates seemed to occur consistently only when the satellite was both closest to the magnetic equator and at its highest altitudes.

In preparing for the Fort Churchill expedition from which he had just returned, Carl Mcllwain had wanted to find out how his detectors would respond to the high-intensity radiation that had been seen in the auroral zone during our earlier rockoon expeditions. To do that, he talked Van Allen into buying an expensive 250 KV direct current X-ray machine and set it up in the north end of the basement. His preexpedition calibrations revealed that that machine could easily drive the GM counters to zero counting rates.

During our March meeting, Carl noted that the zero counting rates being seen in the Explorer I data seemed similar to those he had seen during the calibration of his Churchill instruments. He suggested that the Explorer satellite instruments might be observing a high flux of particles that was blanking the GM counter. He further suggested that study of transitions from normal to abnormal rates might help resolve the riddle. Abrupt transitions would suggest an instrument malfunction, while smooth transitions would suggest that the satellite was moving into and out of a region containing a high radiation flux.18

Thus, at that 8 March meeting, we were already beginning to seriously entertain the possibility that there might be a higher than anticipated flux of charged particles in certain regions above the atmosphere. That information, however, was held very closely to our collective chests until we could be more certain of the situation. Not even other members of the physics faculty were aware of the development at that time.

The Iowa satellite experiment as originally envisioned did not call for any particular urgency in dealing with the flight data. As previously stated, its original purpose had been to assemble a set of data that was comprehensive in its spatial and temporal coverage. We envisioned that the data set would be assembled throughout the satellite’s lifetime and that the analysis process would be done in due course during the following months.

We had no way of anticipating the intensity of the spotlight that soon focused upon our work. The cold war space race introduced a new reality—pressure for early

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results precluded the more measured pace that had been envisioned. Added to that, the unexpected readings created in us an even greater sense of excitement and urgency. We were beginning to understand that we might have come across a new finding of great importance.

During the weeks following our 8 March meeting, while I was busy at JPL with preparations for the second launch attempt of our more complete Deal II instru­ment, Van Allen, Ray, and McIlwain, with a team of student data readers, continued their examination of the Explorer I data. Nevertheless, the data remained largely in­conclusive.

No indication of our growing belief in the possible existence of a naturally occur­ring region of high-intensity radiation appears to have been made at the previously mentioned 11-12 March meetings at JPL. Throughout the rest of that month and early April, there were other external contacts in which preliminary results from Explorer I were discussed. On 20 March, for example, Van Allen talked to a CBS reporter about our results—again, there is no indication that the anomaly was mentioned.19 On 17 March, I talked to a physicist at Northrop Aircraft who was working on a paper on radiation hazards in space. During that discussion, I outlined our general progress to date but made no mention of elevated counting rates.20

Van Allen wanted to be sure of our analysis before mentioning it outside our group.

In the general excitement that followed the successful Explorer I launch, a new satellite program was approved and announced that would capitalize on the now-proven launch capability. The program, with Juno II as the vehicle name, would use a larger Jupiter Intermediate-Range Ballistic Missile instead of a Redstone as its first stage, combined with the Juno I upper stages. It would be able to launch a substantially heavier satellite. On 17 March, Van Allen informed me that our Iowa group would be furnishing an instrument for that so-called IGYHeavy Payload.

Its initial schedule called for a very short developmental period. We were expected to have our instrument prototype ready by 1 June. Thus, the development of our new instrument became an urgent priority for me. As circumstances evolved, that instrument was not actually launched until over a year later as Explorer 7 (after an intervening failed attempt). But those delays could not have been foreseen during the period March through May, when I had to scramble to meet the original schedule. The story of the development and launch of that satellite is recounted in Chapter 14.

Meanwhile, time marched inexorably toward the second attempt to launch Deal II. The Deal IIb payload was launched from Cape Canaveral at midday on 26 March (12:38 EST or 17:38 UT), as described in the previous chapter. After launch, it was renamed Explorer III.

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y the end of the summer of 1958, less than a year after the first penetration into space, three successful Sputniks had led the venture into the new realm, accompanied by three Explorers and a Vanguard satellite.

Both the Soviet Union and the United States quickly tooled up for the unfolding grand adventure and opportunity. In the United States, the Department of Defense established, in February 1958, a new agency for focusing their space program—the Advanced Research Projects Agency, later renamed the Defense Research Projects Agency. In addition to oversight of the Argus program, as described in the previous chapter, it began vigorous work on the reconnaissance satellites that had been a long-standing aspiration of the military and other national intelligence-gathering organizations. It also began to address the urgent needs of the Department of Defense for improved worldwide communications.

A new U. S. agency to oversee the nation’s civilian space program was signed into law on 1 October 1958, just before the first anniversary of the Sputnik 1 launch. That National Aeronautics and Space Administration (NASA) took over responsibility for the scientific missions then in progress and quickly expanded its scope to encompass a vast array of robotic and manned endeavors.

This chapter concentrates on the rapid blossoming of instrumented space research during the rest of the decade of the 1950s.

A major balloon launching campaign was mounted in the spring of 1956, when three flights were made at Iowa City with larger skyhook balloons.49 50 Frank McDonald and Bill Webber had quickly followed their balloon flights on the second Goodfellow expedition with the development of an improved instrument. It contained a thin-lucite Cerenkov detector like the one used previously, but augmented by a Na-I scintillation counter and a GM counter telescope to provide improved measurements of lithium, beryllium, boron, and carbon in the primary cosmic ray radiation. The entire package, along with a camera to record the data, was assembled in a cylindrical aluminum gondola six feet long, 18 inches in diameter, and weighing 130 pounds, as shown in Figure 2.16.

The first two of those launches lofted a large assortment of experiment instruments. On the first flight, the new McDonald-Webber instrument led the chain of packages on the load line. The next package on the line, designed by Laurence (Larry) J. Cahill, constituted an early balloon flight test of the proton free-precession magnetometer that he had been developing for rockoon flights, as detailed in Chapter 4. Next on the line was one of Kinsey Anderson’s GM counter telescopes like the ones he had just flown at Goodfellow. Yash Pal, an Indian research associate at the Massachusetts Institute of Technology, provided a bundle of photographic nuclear emulsion plates. Additional items included a timer and cut-down device for terminating the flight after eight hours, a parachute for lowering the string of instruments after they were cut loose, a camera,

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an altitude-measuring barometer, another bundle of nuclear emulsion plates from the University of Minnesota, and a carefully calculated ballast to control the equilibrium altitude of the balloon. Those components, totaling about 250 pounds, were spaced along the balloon’s 100 foot long load line.

The largest Skyhook balloon used to date, at 244 feet in length before inflation, about 150 feet in diameter when fully inflated, and nearly 2 million cubic feet in volume, was used to loft the first of the three Iowa flights. That first launch was initially planned for about 1 March 1956 but was delayed because of weather. Another attempt was made to launch it on 12 March, but high winds and poor visibility caused further postponement. The launches required a ground wind speed of less than 11 miles per hour to avoid damage to the balloons and their loads during inflation and launch. It was also highly desired that the visibility across eastern Iowa and northern Illinois be clear to enable the chase teams to follow and recover the instruments.

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All conditions were met the next day, when it was finally possible to launch that first Super-Skyhook balloon from a runway at the Iowa City municipal airport. That occurred at 7:47 AM on 13 March 1956.51 The experimenters had made final checks and adjustments on their instruments throughout the night. The balloon-inflation crew began their preparations soon after midnight. Four foot weather balloons were tethered from a panel truck at 150 foot and 300 foot heights to monitor the wind speed and direction. Although the lower test balloon indicated a gentle enough wind for safely inflating the balloon, the higher one revealed a wind shear that could destroy the balloon soon after release. That situation persisted throughout most of the night. As dawn approached, the wind shear finally abated, and a decision to attempt the flight was made at about 5:30 AM. The fleet of vehicles made its way into position at the south end of the runway. That flotilla included a truck pulling the mobile launcher, another truck carrying helium, the panel truck with its weather balloons, the scientists and their instruments, and the beginnings of an entourage of onlookers that eventually swelled to more than 200. Just before the Sun appeared over the eastern horizon, the balloon was laid out on the runway and inflation began. As inflation progressed, the envelope was played out from between large rollers on the mobile launcher. As the helium bubble slowly formed, the flow was stopped at intervals and the platform was pushed forward by the tow truck to play out more of the plastic envelope.

There was great excitement in the local community about this launching. Batteries of newspaper photographers snapped their cameras as the crews worked through the night, and local radio station KXIC began a live broadcast at about sunrise. The growing crowd of onlookers pressed in on the workers—it was too early in the Space Age for us to have thought much about crowd control. As the free lift reached about twice the payload weight, the flow of helium was stopped. At that time, the helium was contained in a small bubble at the very top of the balloon. Although occupying only about 1 percent of the balloon’s volume at ground level, this bubble would expand as the balloon ascended through the decreasing air pressure until it completely filled the balloon’s spherical envelope at about 113,000 feet, or 21 miles. Until it was cut down by the timer, the balloon would float at about that altitude, moving up or down slightly as the gas temperature varied due to changes in solar illumination.

After everything was ready for the balloon release, a hold was called. That lasted for an hour while the pressing crowds were moved back and the launch platform was realigned to accommodate a slight shift in the wind direction. Finally, one end of the launch platform’s top roller was released, and the balloon floated free. Being at the top of the load line, Frank’s gondola was immediately lifted from the ground. Since the wind was blowing the balloon slowly northward, the other teams had to run across the ground with their equipment packages until the balloon took up the slack in the load line. Otherwise, the instruments would have been dragged across the ground and damaged. This was always an exciting (often comical) phase of a balloon

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launching operation. There is no greater motivation for an Olympian sprint than a graduate student’s need to thus protect the prized product of many months of intense laboratory preparation, and to keep alive his hopes for a timely completion of his thesis and receipt of his degree.

The chase plane departed immediately after the launch. The assembled crowd watched the balloon and its payload shrink to a small dot in the sky and eventually disappear. Cahill and an undergraduate assistant departed to chase the balloon with a truck on loan to the Physics Department from the Navy. They followed the balloon eastward, stopping about every 50 miles to record the payload signal, until they were stopped by Lake Michigan. A full discussion of that flight of Larry’s instrument is contained in the thesis for his M. S. degree, which he received in 1957.52

The other experimenters rushed back to the physics building, where Kinsey Anderson was able to monitor the radio signals from his instruments until mid­morning, when the balloon passed out of radio range. Frank McDonald’s data were being recorded by a special camera in the gondola, so he could do nothing but await the gondola’s return to see if his instruments had performed satisfactorily. The nuclear emulsion plates, of course, also needed to be returned for laboratory analysis.

High-altitude winds turned out to be much stronger than expected. Within the first 200 miles, the balloon had far outpaced the chase truck. It reached upstate New York by the time the timer cut the load line and the parachute lowered the payload to the ground. The chase plane was out of visual contact due to thick weather much of the last portion of the trip, but the pilots were able to follow the balloon’s approximate path with the plane’s radio direction finder. They believed that the balloon’s equipment had descended about 40 miles south of Rochester, and so landed at the Rochester airport. A ground search, however, was unsuccessful. It wasn’t until 48 days later, on 30 April, after a snow cover melted, that a farmer found the equipment 30 miles south of Utica, about 120 miles farther east than expected. The equipment was returned, the farmer was paid the promised reward of $150 for finding and reporting it, and Frank and the other scientists began to analyze their flight data.53

The second and third flights used somewhat smaller 120 foot diameter balloons. The primary instrument on the second flight was another of Frank McDonald’s heavy – nuclei cosmic ray instruments. It was in a gondola similar to that of the first flight, but somewhat lighter at 110 pounds. Carl McIlwain flew a single GM counter package sim­ilar to the ones he had launched on the 1955 rockoon expedition. Also attached to the load line were nuclear emulsion packages from the University of Minnesota, Washing­ton University in St. Louis, Missouri, and the Massachusetts Institute of Technology.

The second flight was launched at 6:27 AM on 20 March. Everything went more smoothly, the balloon’s speed aloft was more nearly as expected, the skies were clear,

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and the twin-engine Beech chase plane was easily able to follow it. After seeing the equipment string descend under its parachute about seven miles northwest of Mount Pleasant, Michigan, the pilots landed their plane at the nearest airport. People on the ground also saw the instruments descend, and the flight equipment was in the hands of the Michigan State Police 20 minutes after it landed. The pilots in the chase plane returned the equipment to Iowa City the following day.54

For the third flight, graduate student Raymond (Ray) Missert had prepared for a long-duration 24 hour flight to study variations in the cosmic ray intensity. Available records do not contain details of that flight, but it appears to have taken place, as Ray obtained his Ph. D. degree the following year based on a dissertation on that subject.55

Those three flights were supported once again by the ONR and the Atomic Energy Commission. The balloon operations were handled by Otto C. Winzen, chief flight engineer Edward Lewis, and their crew from Otto’s Winzen Research Company in Minneapolis. The Iowa experimenters were assisted by a battery of student aides and other assistants.

This chapter relating balloon, rocket, and rockoon work rounds out my account of University of Iowa high-altitude scientific research to the point where the International Geophysical Year provided an opportunity for a greatly expanded program, including the possibility of launching artificial Earth satellites. The balloon, rocket, androckoon work described in this chapter produced important scientific results, sharpened our technical skills, and shaped a high-altitude research laboratory that was second to none.

I received my bachelor’s degree at the winter convocation in February 1956 and was ready to begin my graduate work. My personal involvement with the Iowa balloon and rockoon programs, per se, essentially ended when I turned to developing Earth satellite instruments in March 1956.

Since the data recorder developed for Vanguard and launched on Explorer III played such an important role in the radiation belt discovery, a few more words about the device are appropriate.

Variations on the Iowa design Variations of my recorder design were developed by two other groups. Starting in late 1956, Gerhardt Groetzinger and his group at RIAS in Baltimore, Maryland, designed a Vanguard instrument package with an ionization chamber for measuring the flux of primary cosmic ray nuclei with atomic number greater than eight. He, too, needed to obtain broad orbital coverage. In May 1957, I sent him a full set of drawings and an actual working model of my recorder (unit 2 of the Mark III design), as well as my electronic circuit designs. He used that material as the basis for a version for his instrument.

Unfortunately, Dr. Groetzinger died before his instrument could be launched. That ion chamber, with P. Schwed of RIAS and Martin A. Pomerantz of the Franklin Institute serving as investigators, was eventually launched aboard Explorer 7 on 13 October 1959. Explorer 7 employed a solar-powered, continuously radiating, rel­atively high power 20 MHz transmitter that could be received by radio amateurs via conventional receivers throughout the world. Thus, adequate coverage by direct radio transmission was expected, and their tape recorder was not needed in that satellite.

For many years, I enjoyed a wonderfully productive relationship with Verner (Vern) E. Suomi at the University of Wisconsin. He first contacted me in mid-1956 about the possibility of using my recorder and electronic circuit designs, and I immediately provided a full set of drawings and other details. His “Proposal on Radiation Balance of the Earth From a Satellite,” which included a variation of my recorder design,

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was submitted in the early fall as a candidate for flight in the Vanguard program. He received preliminary endorsement from the IGY committee in early December 1956. On 25 February 1957, they received formal approval and funding for their proposal, and a month later, they reported that fabrication had begun on their tape recorder – sequencer. Their variation on the design increased the recorder tape speed to two steps per second instead of one and added an elaborate set of sequencing switches that cycled between five sensors and two 10-stage scaler circuits. Those switches were actuated by the ratchet drive in the tape recorder.

An attempt was made to place the full University of Wisconsin instrument into orbit on 22 June 1959 on Vanguard Satellite Launch Vehicle (SLV)-6, but that launch attempt failed. A modified version of the instrument was finally orbited aboard Ex­plorer 7 on 13 October 1959. Since that satellite benefited from global reception of the higher-powered 20 MHz transmissions, as mentioned before, the data recording feature was not needed and dropped. However, the stepping mechanism and general layout were used for operating the programming switches.

Other early satellite data recorder designs A somewhat similar unit was developed in the early 1960s by the Raymond Engineering Company in Middletown, Connecti­cut, under contract from JPL. It had many similarities with the SUI recorder—it also operated entirely in the digital domain, with the tape advancing one physical step only when an input pulse was applied. The Raymond device, however, being produced later than the Iowa design, was able to use a superior configuration. Although its tape was also held in tension by a spring, the spring applied a torque to the tape take-up spool rather than the supply spool, and the tape was pulled forward by the spring when it was incrementally released by an escapement mechanism similar to that found in mechanical clocks. The Negator spring used in their design provided a nearly constant torque. An electric motor drove the tape in the other direction at a nearly constant speed to read out the data upon command.

The tape in the Raymond device moved 0.005 inch for each step, the same as in the SUI recorder. With a much longer tape, it had a total capacity of 100,000 bits versus 8000 in mine. That made it substantially larger, 2.25 by 4 by 5 inches, and heavier. Its power consumption was comparable to that of the SUI recorder. Developed to permit individual instruments aboard future multi-instrument spacecraft to have their own data storage, its use was overtaken by two developments. First, the rocket launching capacity increased rapidly after the initial space launches, so that extreme weight minimization was less important. Second, demands for data storage and transmission increased dramatically as the instruments became more discriminating, and the Raymond design did not meet that need.

Only a breadboard model of the Raymond recorder was built for testing, and it was never used in flight.30

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A completely different type of space tape recorder was launched into orbit on 17 February 1959 as a part of the Vanguard II instrument package. That recorder, de­signed by a group under William Stroud’s leadership at the U. S. Army Signal Corps Engineering Laboratories at Fort Monmouth, New Jersey, was designed to record cloud cover distribution over the daylight portion of the satellite orbit. It was a minia­turized version of more conventional analog recorders, with a weight of a pound or so. It used a 75 foot length of tape in an endless loop that did not require rewind­ing and had recording and playback times of 50 minutes and 1 minute, respectively. The recorder operated properly in orbit. Interpretation of the data was not possible, however, because of the unanticipated complex rotation of the satellite.

As mentioned earlier, the Soviets included a much larger data recorder in Sputnik 3, launched on 15 May 1958. However, that recorder failed before the launch. Political considerations caused them to launch without the delay that would have been required to fix the problem. Thus, they were deprived of the continuous data coverage that they wanted.

Explorer III tape recorder summary The Explorer III tape recorder set new stan­dards in terms of size, weight, required electrical power, and ruggedness. Some of the recorder’s most notable features were as follows:

• The final model was only 2.5 inches in diameter, less than 3 inches long, and weighed just over eight ounces.

• Its average power consumption was only 0.035 watts. That low power require­ment was a major factor in permitting the full Explorer III instrument to operate in orbit for 44 days.

• It was fully digital in its operation, making it relatively insensitive to temperature, battery voltage, and other variables. The fact that the tape was motionless most of the time contributed to the low power demand.

• All moving mechanical components except for the playback solenoid were dy­namically balanced, making it largely insensitive to vibration and various trans­lational and rotational motions of the satellite.

• All mechanical components were physically constrained so that high acceleration and shock in any direction could not damage the recorder.

• Ball bearings held friction to a minimum. Nineteen of them supported all rotating components and served as cam followers. The smallest ball bearing was only 5/32 (0.156) inch in outside diameter.

The tape recorder required more than 2000 hours of precision tooling in the Physics Department instrument shop over a one and a half year period. Edward (Ed) Freund worked with me as the principal instrument maker.31 He was helped at times by shop manager Joseph George Sentinella and fellow instrument makers Robert (Bob)

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Markee and Robert (Bob) Russell. For their work on the data recorder, the four were recognized in 1959 with Certificates of Recognition from the American Society of Tool Engineers.

I kept a spare recorder in my possession from the time of my departure from Iowa City in 1960 until early 1968. That year, I offered it to the Smithsonian Institution’s National Air and Space Museum, and arrangements were made with Frederick C. Durant III to transfer it to their care. In due course, it was cleaned and restored to fully operating condition by Ed Freund. In September 1968, I carried it to Washington and handed it to Fred. The official transfer to the museum was by a letter from Van Allen.32

The unit was identical to the ones launched in Explorer II (launch failure) and Explorer III, except that its relatively short-lived magnesium coating was replaced with gold plating to make it more immune to long-term oxidation.

Although the device included a number of unique and remarkable features, the Uni­versity of Iowa business office decided not to apply for patents. They concluded that there would not be enough demand for similar devices to make patenting economically attractive.

The staffs at ABMA in Huntsville and JPL in Pasadena did not wait idly for the final Washington approval—the initial Sputnik launch was their call to action. General Medaris took an audacious step only a few days after the launch by instructing von Braun and his organization to take Jupiter C, Missile 29 out of storage and begin preparing it for use. Although the general lacked authority for that action, the amount of money was small, and he figured that he could hide it if necessary. He was absolutely convinced that the Vanguard effort would run into trouble.7

Thus, von Braun and Pickering’s people began implementing the plans on which they had been quietly working. Although the tank of Missile 29 had been elongated earlier to hold more fuel and oxidizer to increase its performance, and although the engine had already been test fired with the new hydyne fuel in October 1956, many other changes were required. The vehicle had to be fitted with an attitude control system that would reorient it during the coasting period following first stage burnout,

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so that the cluster of upper stages would be horizontal when it reached the highest point in its trajectory. The apex predictor that Stuhlinger had built had to be integrated into the launch operations procedures so that it could be used in firing the second stage at just the right moment.

Both ABMA and JPL intensified their studies of the dynamics of injecting a satellite into orbit, maintenance of a durable orbit, satellite temperature control, and other technical factors. Most importantly, they began to tie the numerous studies, hardware, and software efforts together to produce a system that would operate effectively as a whole.