Category Dreams, Technology, and Scientific Discovery

ithout a doubt, the most momentous event during this period of early space exploration was the discovery, from the data obtained from Explorers I and III, of what we dubbed initially as simply the high-intensity radiation. It has come to be known commonly as the Van Allen Radiation Belts. This discovery was a serendipi­tous event. The original purpose of the experiment had been for a rather straightfor­ward extension of the cosmic ray research that had been under way for many years. That objective was immediately overshadowed when the new discovery thrust itself upon us.

There have been many accounts of the discovery, some of them misleading, incom­plete, or contradictory. In the interest of historical accuracy, there is heavy reliance in this work on primary documentation, that is, material that was written by direct participants at the time of the activity. Those include a variety of archival materials, personal files, and many papers and other published and unpublished accounts.1,2’3’4 There was secondary dependence on the recollections of direct participants, including a number of unpublished exchanges.5

It should be noted that there is a relative lack of primary documentation for one key period—much of the month of April 1958. Laboratory notebooks and personal journals of the four major participants, Van Allen, McIlwain, Ray, and this author, are strangely deficient. It was a time of unusually intense activity—all of us were so completely absorbed in following up on the exciting new findings, that our normal habits for record keeping appear to have been set aside for a while.

Van Allen, the principal investigator and intimately involved in all aspects of the project, was an unusually meticulous record keeper, and he retained his many journals, diaries, notebooks, day-to-day notes, calendars, meeting files, travel records, letters,

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and so on. As mentioned earlier, they reside now, along with complete cataloging, as a professionally maintained collection by the Department of Special Collections in the University of Iowa Libraries.

I was responsible for the cosmic ray instrument development, for our field activi­ties, and for designing, setting up, and running the University of Iowa data-processing facilities. Although participating at times in the data analysis effort, much of my atten­tion was directed to the instrumentation, operational, and data-processing activities. My work is also thoroughly documented. It includes extensive personal journals, notebooks, calendars, meeting files, travel records, photographs, sample data records, letters, and so on. Arrangements have also been made to preserve most of my materials as another special collection in the University of Iowa Libraries.

Carl McIlwain concentrated on developing a thorough understanding of the behav­ior of Geiger counters in the presence of intense radiation and on working with Ernie and Van in pondering, unraveling, and describing the new phenomenon. Carl’s record keeping was intermediate in scope. His records, combined with his keen recollection of events that took place during the 1950s, have been instrumental in resolving some of the conflicting details. Discussions are under way about also placing Carl’s records in the University of Iowa Libraries.

Ernie Ray took charge of the initial processing and plotting of the Explorer I and III flight data at Iowa City. He was an enthusiastic participant, throughout the period, in developing an understanding of the physical processes being observed. Ernie’s record keeping was nonexistent—his shirt pocket served as his file cabinet. Having died in 1989, his personal memories can no longer help us. His contributions to this account are based primarily on the recollections of his wife, Mary, some of his data plots, and a few short notes.

Upon Van Allen’s return to Iowa City on Friday, 2 May, he, Carl, and I met to plan our work. Additional personnel would be needed, and more student helpers were quickly identified. Arrangements were made with Stuhlinger for ABMA to send engineers to help us on short-term staffing loans. In addition, Huntsville would detail an engineer to our laboratory to help us over a longer term. Importantly, in the process of helping us, those engineers would learn what they needed to know for testing our satellite payloads and integrating them into the launch assemblies at Huntsville.

Our work progressed at breakneck speed. Carl concentrated on developing the new scintillator counters. One was for measuring the average current (representing total integrated energy) over a very wide intensity range, while the other included a pulse

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height discriminator to provide information on the particle energy spectrum. One of my early tasks was to develop a faster scaling circuit that would work with GM counters (Anton type 302) having a smaller cross section than the earlier Explorer units by a factor of about 100 times. The scintillation counters and faster GM counters represented the first configuration explicitly designed to follow up on the new radiation belt discovery by making measurements to much higher intensities than had been possible with the earlier Explorers.

Within several days, we had detailed the final detector configuration, and I sent that to Ernst Stuhlinger at Huntsville.15 Within several more days, engineers began arriving from Huntsville. Hermann Wagner was the first—in short order, we were visited by specialists in structures, electronics, environmental testing, and payload checkout, and H. Burke arrived to help us over a longer period.

Relating the details of the many activities that took place during the next weeks would be a book in itself. As already stated, the ABMA at Huntsville carried the primary mission responsibility. I worked extensively with Ernst Stuhlinger, Joseph Boehm, and Charles Lundquist in coordinating many of the programmatic issues. The working-level contacts that I remember with special fondness include (in alphabetical order) Tomas (Tom) A. Barr, H. Burke, George Campbell, Charles Chambers, Harold Donnelly, James Warren Harper, Gerhard Heller, Hans Kampmeier, Samuel (Sam) Stevens (Huntsville’s payload manager), Arthur (Art) Thompson, Willis Underwood, and Hermann Wagner.

I served as SUI’s project manager, overall system designer, coordinator, and equip­ment and supplies procurer. By mid-project, William (Bill) Whelpley, a young engi­neering student, had become my right arm, taking responsibility, among other things, for a substantial portion of the field activities. He continued his work in the laboratory for a number of years, becoming a very competent satellite designer in his own right.

Carl McIlwain carried the full responsibility for the new scintillation counters (Figure 13.1), with Ernie Ray working with him from time to time. Carl was also assisted by Dale (Pete) Chinburg, who prepared his numerous drawings. Pete also remained with the Iowa group for a number of years, where he served primarily as a payload coordinator and manager.

Wayne Graves continued his earlier assignment from Collins Radio in Cedar Rapids, providing very skillful help with the electronics design and construc­tion and with GM counter calibration. Charles Cook, Riley Newman, and Chris Richards provided additional laboratory assistance. Drafting support was provided by Mr. Schnerre.

The JPL provided the low-power transmitters, subcarrier oscillators, antenna gaps, and outer shells with their temperature-control coatings. In addition to working with

CHAPTER 1 3

director Bill Pickering, chief scientist Eb Rechtin, and senior engineer Henry Richter, I worked at various times on this project with Walt Downhower, Karl W. Linnes, Phil D. Potter, Lee Randolph, Fred Riddle, and Al Wolfe.

The NRL in Washington provided the high-power transmitter. My primary interface there was with my good friend Marty Votaw.

The U. S. Signal Research and Development Laboratory at Fort Monmouth, New Jersey, provided the battery packs through their contract with the Mallory Battery Company. My primary contacts there were Hans Ziegler and A. Legath.

During the instrument development, Pentagon brass and other officials showed up at the physics building from time to time. They returned home incredulous:

Visitors to the University of Iowa during the spring and summer of 1958 were astonished to find that a crucial part of this massive undertaking had been entrusted to two graduate students, and two part-time professors working in a small, crowded basement laboratory of the 1909 physics building. But we knew our business and were in no way intimidated by representatives of huge federal agencies.16

Despite the secrecy, we could build all of the equipment in the open, since the satellite and its instrumentation served officially as an International Geophysical Year (IGY) program to extend our investigation of the natural radiation discovered by Explorers I and III. Only the second mission to study the nuclear blasts was held in strict confidence by a small group of us who were building the instrument. In fact, only Van Allen and McIlwain had access to the full range of details. My knowledge

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was limited to a basic understanding of the mission and to details necessary to build the instrumented satellite, test it, and interface it with the launch vehicle.

The Argus Project was helped immeasurably by the assignment of a very high mil­itary priority that helped to cut through the red tape and delivery delays. Specifically, it enjoyed a DX-A2 designation, where the DX rating was the highest Department of Defense priority, and A2 designated missile-related contracts. Its high priority enabled us to obtain materials that existed anywhere in the national manufacturing, warehous­ing, and delivery chain, regardless of who may have ordered them. Our procurement of a complete vibration test system illustrates the benefit of that arrangement. It was a large aggregate of electronic and electromechanical assemblies capable of vibra­tion testing our satellite. It included four racks and a console filled with electronics equipment, plus a vibration exciter on which the equipment to be tested was mounted. Those systems were normally produced at the factory only upon receipt of concrete orders, so that the normal delivery time was substantial. We ordered one in late May, and it was delivered and placed in operation in about six weeks. In order to accomplish that, a system that was being built for another customer was intercepted and delivered to us. That system, shown later in the lower left corner of Figure 15.2c, turned out to be operational too late to help much with the Argus Project, so the Explorer IV and V vibration testing was conducted at Huntsville. Our vibration test system was used extensively over time on later projects.

We had a substantial body of experience with most of the circuits and components used in Explorer IV, as they were similar to those in the earlier Explorers. Carl McIlwain’s new detectors, however, introduced a completely new element. During their environmental testing, failures occurred with a calibration relay and with the Radio Corporation of America (RCA) type 6199 photomultiplier tubes. A summary of the problems on 25 June 1958 indicated that the relay problem had been satisfactorily resolved. Although RCA had made some improvements in the tubes, a complete redesign was not possible. The launches would have to proceed with somewhat less than full confidence in them.

Specifically, after the initial tests, their failure rate was determined to be about 25 percent. The late June report summarized the situation, as it had evolved by that time, by stating that the tube was not designed for the rocket launch environment, that no other suitable tube was available, and that there was no time for complete redesign of the tube’s construction. The RCA was able, however, to make some minor changes, and Carl made an improvement in the exterior mounting arrange­ment to further isolate the tube from payload vibration. In addition, the vibration test levels were somewhat reduced. Because of the urgency of the mission, the decision was made to launch the payloads with an estimated failure rate still at about 5 percent. Fortunately, Explorers IV and V were launched without instrument failure.

The photomultiplier tube evolving from that design effort served for a number of years as the standard for similar rocket and spacecraft detectors.

On 5 May, Stuhlinger called a planning meeting at Huntsville. Neither Van Allen nor I could go because of the press of our work in Iowa City, but we participated via a telephone conference call. Many issues involving receiving stations, orbital computation, payload weight, and the assignment of responsibilities for providing the various components were worked out. That meeting was followed by another on 10 May, which I did attend. Engineers were there from ABMA, JPL, and the Signal Corps Engineering Laboratory in New Jersey, while NRL participants joined us via telephone. During that meeting, a more detailed delivery schedule was established. It was tied to the requirement that we have our satellite in orbit before the first Argus high-altitude nuclear detonation, then scheduled to occur on 31 July.

During the preparations for the Explorer IV and V launches, we employed light military and chartered civil aircraft to shuttle personnel and equipment between Iowa City, Huntsville, and Washington, D. C. The schedule was too pressing for us to wait for commercial flights. At least 15 of those special flights were made.

On 7 June, Carl McIlwain and I packaged our prototype Explorer IV instrument assembly (Figure 13.2) and carried it via an Army Twin-Beech aircraft to Huntsville, where we test-fitted it into the outer satellite shell and began the process of balancing and aligning it. Two days later, Carl returned to Iowa City, where he prepared and sent

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some repair parts to me. I returned to Iowa City with ABMA’s George Campbell and Willis Underwood to make a new circuit board on 14 June, and five days later, I flew again to Huntsville with the result. On 21 June, it was back to Iowa City to work on the flight units.

About three weeks later, on 2 July, Bill Whelpley flew to Huntsville with our first flight unit for an extended stay to help with the testing. The next week saw the rapid shuttling of the flight payloads between Iowa City, Huntsville, and Washington. Flight Payload 1 moved from Huntsville back to Iowa City for transmitter rework, back to Huntsville, thence to NRL in Washington, and finally back to Huntsville. Payload 2 also made a trip to NRL for transmitter modification.

On 9 July, I left again for Huntsville to deliver the third flight unit and to remain for a week for extended testing. The rest of my family drove to Huntsville in our personal car to join me. While in Huntsville, we were the guests of gracious hosts George Campbell and his family.

We had a particularly rough night on 11 July, when we repaired a vacuum problem in flight unit 1 and were finally able to run a satisfactory vacuum test on it. Antenna matching problems with that flight unit were also resolved during the night, and we corrected a problem with the high-power transmitter in flight unit 2 and passed a vibration test with it.

And so it continued during the next days. I finally had a much welcomed short break on 16 July, when I drove our family to Cape Canaveral for the launch. I remember having great fun with Rosalie, Barbara, Sharon, and baby George during the drive with group singing, including many spontaneous variations on “Purple People Eater.”

Bill Whelpley remained at Huntsville to continue the testing on flight units, and Carl McIlwain soon joined me at the Cape. The pace there was just as hectic as it had been at Huntsville. During the next few days, I completed the final inspection and calibration of flight unit 1 and worked with the ABMA, NRL, JPL, and Cape personnel on fitting the payload to the launch vehicle, balance tests, and radio frequency testing and calibration. Other activities, such as working out the countdown procedures and checking ground receiving station readiness, occupied the remaining time leading up to launch.

We soon began concentrating on the final preparations of the most promising of the flight payloads. On 22 July, we completed the last radio frequency interference tests with it mounted on the launching vehicle, as it stood upright in the gantry.

Two incidents remain vivid in my memory that emphasize the informality of that early space flight era. A day or two before the Explorer IV launch, I was called to a meeting with Major General Donald N. Yates, Commander of the Air Force’s Atlantic Missile Range. He had the ultimate responsibility for flight safety. As mentioned earlier, an orbital inclination of 51 degrees had been chosen, compared with 33

CHAPTER 13 • ARGUS AND EXPLORERS IV AND V 373

degrees for Explorers I, II, and III. Those earlier launches involved aiming the rockets slightly south of due east from Florida, where their flight paths were well clear of any substantial landmasses. On the other hand, Explorers IV and V in order to achieve the desired higher inclination, had to be aimed northeast, with their paths passing just off the U. S. East Coast. In fact, the swath that included their intended paths, widened by allowances for reasonable aiming errors, included possible passage over the east coast of Newfoundland.

General Yates wanted to be assured that the flight would be reasonably safe. This was the easiest argument that I ever had to make, as he was just as eager to launch as we were. All I had to do was to mutter a few words about the low population density on its expected course and the improbability of hitting any populated areas if the vehicle should happen to stray, and he quickly said, “Let’s go.”

I especially marvel at the second incident. On 23 August, I performed a careful inspection of the number one flight unit being readied for the Explorer V launch. I found that many of the wires in a bundle of interconnecting wires were nearly broken off where they were soldered to the terminals.

Teflon insulation for electronic circuit wire had just made its appearance. The coating process had still not been perfected for copper, although it was well understood for silver. So the hookup wires that we selected were made up of many fine silver strands. The main problem with that was that the silver strands broke easily when flexed repeatedly. To compensate for that, the manufacturer included a stainless steel strand in the center of the bundle. The stainless steel strand provided strength, while the silver strands provided high electrical conductivity.

Our chosen flight instrument had been reworked so much that the silver strands in many of the interconnecting wires had broken, leaving only the single stainless steel strand intact. That, of course, could not be permitted for the flight. I did the thing that I thought most reasonable under the circumstances: I plugged in my soldering iron and went to work on reconnecting the entire main wiring harness, containing dozens of individual soldered connections.

Under the operating procedures of even those early times, that kind of rework would not have been attempted that late in the launching process. The launch would have been delayed, the repairs made, and a number of the electrical and environmental tests repeated to make sure that the work had been done properly. In this instance, though, time would not permit the standard procedures because of the inflexible Argus schedule. I felt comfortable in undertaking the rework, since I had personally installed the wiring harnesses in the first place.

The Huntsville engineers, I discovered later, were horrified. While I was soldering away, a number of them quietly retreated to a nearby trailer-workshop to discuss the situation. After a lengthy debate, and in consideration of the extremely tight schedule, they decided to let “that crazy Iowa student” proceed with the repairs. I completed

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the work in short order, and we proceeded with the remaining preparations as though nothing unusual had happened.

The repair worked perfectly.

With the experience that everyone had gained with the earlier Explorer launches, the countdown procedures had become very well established. We even had a written procedure in case the payload instrument should malfunction during the countdown. It spelled out the precise conditions that would call for either a hold or postponement. Interestingly, my copy was hand annotated “hide,” probably indicating that we did not want to reveal anything to the public other than full confidence in success.

The countdown began early in the morning of 26 July. The launch was completely normal, and Explorer IV was successfully in orbit later that day.

The satellite’s initially computed orbit ranged from 164 miles at perigee to 1381 miles at apogee, with an inclination relative to the Earth’s equator of 50.1 degrees. The initial orbital period was 110.1 minutes. Because of the rather low perigee, it decayed from its orbit and reentered the Earth’s atmosphere a little more than a year later.

With its attached final rocket stage, Explorer IV was, like the earlier Explorers, 80 inches in length and 6 inches in diameter. The total weight placed in orbit was 38.43 pounds, of which 18.26 pounds was the instrument, 7.50 pounds was the shell, and 12.67 pounds was the exhausted final rocket stage. The increased payload weight and higher orbital inclination were made possible by an upgrading by JPL of the high-speed rocket stages. [10]

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the NRL engineers checked the transmitter and found problems, and a replacement transmitter was flown from Washington and installed. Flight Payload 1 was chosen as the best-performing instrument.

The launch countdown began at 5:30 PM on 23 August, and ignition occurred early the next morning, but with a hugely disappointing result. The final rocket stage failed to ignite, and Explorer V ended up somewhere at the bottom of the Atlantic Ocean.

The day after the Explorer V launch attempt, I detoured to Huntsville for discus­sions about the IGY Heavy Payload, and two days later, I eagerly rejoined our group in Iowa City.

James Van Allen was a truly remarkable teacher, working in a gentle but persistent way. His most powerful tool was his use of the carefully phrased question. It invariably caused us students to go away and think critically about the issue and to come up with our own solutions. If we made wrong assumptions or arrived at wrong conclusions, he would gently steer us in the right direction.

Many of us have expressed our admiration for Van Allen’s willingness to turn students loose on such important projects and to give us great freedom in carrying them forward. His guidance provided just the right amount of direction to advance our skills and understanding of the work, but at the same time to keep us from getting into too much trouble. Only with later widening experience did I come to appreciate the immensity of the risks he took with us.

Although we all made our individual contributions toward the State University of Iowa Physics Department’s rise to leadership in the new branch of research, it was Van who provided much of the vision, gained a major portion of the outside programmatic and financial support, and had the most to lose if we failed.

CHAPTER 16 • SOME PERSONAL REFLECTIONS 441

I visited with Van only a few weeks before he died, and we talked of many things. One of our topics was the discovery of the Van Allen Radiation Belts.

Van had posed a question to me a few months earlier: “Would we have discovered the radiation belts with Explorer I alone, if we had not had the onboard-recorded data from Explorer III?” We exchanged independent written responses before the visit. In his response, he asked further, “Would we have concluded that our detector on Explorer I was hopelessly erratic and despaired of getting any credible data? Or would we have persisted in reading and compiling the data, recognized the dead time problem, and made the radiation belt discovery? If so, how long would this process have taken?”

Van asserted that we would have organized enough Explorer I data so that we would have discovered the high intensity of geomagnetically trapped energetic particles, but he did not speculate further. My response was that we would have made the discovery, but that it would have taken longer. I further speculated that we would likely still have made the announcement before the Soviets, but posited that the trapped radiation announcement would have been less dramatic and have had less impact on jump­starting an energetic space research and exploration program.

He also asked during our visit, “Do you know that a detailed description of how the proximity fuse worked has never been written?” It is remarkable but typical that, even as he lay in his bed near the end of his life, his writing pad was on his bedside table, and he had begun drafting a paper on that subject.

Van was a truly remarkable person, and I was indeed fortunate to have had him as a mentor and friend

Meredith’s initial detection of the auroral soft radiation in 1953 led to vigorous follow­up work for a more discriminating examination of its latitude dependence, compo­sition, and directional characteristics. In addition to his early work on the balloon in­struments, as described in the preceding section, Frank McDonald joined in the effort to further define the new phenomenon. Over the winter 1953-1954, working with Mel Gottlieb and Bob Ellis, he developed two new rockoon instruments.16 I worked with them during most of May and June 1954 to build a set of flight instruments.

The first new rockoon instrument paired the same type of GM counter that had been used on the 1953 expedition (minimally shielded with 30 mg/cm2 in the counter wall, plus 160 mg/cm2 in the nose cone) with a second identical Geiger counter having additional shielding (150 mg of aluminum and lead). That instrument also included a photoelectric rocket-orientation indicator.

The second payload type was fundamentally new for the rockoons. Derived from the balloon instruments on which McDonald and Webber had been working, it employed a Na-I (thallium-doped) scintillation crystal mounted on a photomultiplier tube. That scintillation detector was mounted below a single thin-walled GM counter located in the nose of the rocket. The Geiger counter pulses gated the output of the scintillation detector. When both were triggered within a very short time, usually by a single particle traversing both of them, the amplitude of the scintillator detector pulse was

CHAPTER 2 • THE EARLY YEARS 37

telemetered. The raw Geiger counter pulse rate was also telemetered. Thus, the instrument was to provide information about particle type, energy, intensity, and direction of arrival.

The SUI 1954 field expedition contingent consisted of Frank McDonald (heading the team) and Bob Ellis. The NRL again fielded a team. They all left from Boston on 15 July on the USN icebreaker USS Atka.17

Two shakedown launch attempts on 16 July due east of Boston were spoiled by rocket ignition problems. So-called redesigned, greatly improved igniters had been shipped with the rockets, but, like the igniters on the 1953 expedition, they failed to fire the rockets at altitude. The team prepared a version of the Jones Igniter so resourcefully worked out during the 1953 expedition. That proved to be completely successful, and it was used throughout the rest of the expedition.

The third rocket in the series, with the improvised Jones Igniter, was launched three days later while they were still en route to their primary area of interest. Although the rocket ignited properly, that flight experienced a partial telemetry system failure and did not produce usable data.

The first fully successful flight (SUI flight 27) occurred off the northern tip of Labrador near 59 degree north geographic latitude, or at about 70 degrees north geomagnetic latitude. That, with 10 other launches, was clustered in and near the heart of the auroral zone during the short five-day period from 21 through 25 July 1954. Seven of those flights reached observational altitudes with operating instruments.

Ellis, Gottlieb, and Meredith reported later on the data from two of the successful flights of the paired GM counters. One of those flights, number 36, dramatically revealed the auroral soft radiation, as shown in Figure 2.7. The effect of the additional shielding of the second GM counter is clearly evident.18

The data from McDonald’s scintillation/GM detectors was, at first, puzzling.19 That question was partly resolved in 1954, and McDonald, Ellis, and Gottlieb reported that, of three successful flights of that instrument, two revealed the soft radiation.

The group’s experience with balloon-, rocket-, and rockoon-launched instruments put us in an excellent position to develop the new satellite instrument. We were well versed in building the types of electronic circuits that would be required, and we had learned how to build them ruggedly enough to withstand the stresses of rocket firing. Nevertheless, designing an instrument for a satellite added new dimensions. In my 26 April 1956 notebook entry, I listed the major problems foreseen in developing the

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Vanguard instrument. Foremost among them were (1) learning how to use transistors, (2) developing the in-orbit data storage system, and (3) miniaturization.7

The transition from the vacuum tubes that we had been using in our balloon and rocket instruments to transistors was essential in order to minimize the instrument’s size, weight, and power demand. I worked hard during the initial few months, and, indeed, throughout the entire developmental period, to build miniaturized circuits that would operate at the required low power levels and still be highly reliable over the expected range of operating conditions.

Before starting work on the satellite project, I had never even seen a transistor, let alone developed a circuit that used one, although I had been following their evolution through the engineering literature out of general curiosity. The very few existing books on transistors were not at all helpful. They focused on a network analysis approach to understanding the basic characteristics of the devices and were not useful in designing actual working circuits. I quickly abandoned any theoretical approach for designing circuits and adopted a much more pragmatic experimental approach. Starting with appropriate circuits from our vacuum tube experience, I substituted transistors, and then varied circuit topologies and component values until I obtained the results that I was seeking. That approach eventually gave me considerable insight into the internal workings of the new devices, and I soon developed the same intuitive familiarity with transistor circuit design that I had enjoyed with vacuum tube electronics.

Admittedly, that first U. S. satellite instrument appears trivially simple by the stan­dards of current massively dense fabrication technologies. Today, all of the Explorer III electronics circuits could be fabricated in one or a few very small silicon chips. But those technologies were not available in the 1950s, and we were pushing the then-available state of the art.

The second major challenge was in devising a suitable device for storing the data during each orbit, and for relaying them rapidly to the ground when the satellite passed over the ground stations. As already mentioned, Van Allen’s proposal for the cosmic ray experiment was such that data recovery over a broad range in geomagnetic latitude was essential. Both his late 1955 and early 1956 cosmic ray proposals focused on the use of networks of ground receiving stations for that purpose. Although he did mention the use of “a magnetic storage drum” in his second Ann Arbor paper dealing with the auroral soft radiation, he did not mention onboard storage in the cosmic ray proposal. That was in spite of the fact that, from the beginning of our discussions in the fall of 1955, he and I had talked about its desirability and some early ideas for achieving it. Certainly, from very early, he strongly favored an approach employing onboard storage because of its vastly greater data coverage, even though we knew that development of the in-flight hardware would be challenging.

Van Allen and I increased our efforts immediately following the Ann Arbor meeting to examine various options for the instrument configuration. We continued to keep

CHAPTER 5 • THE VANGUARD COSMIC RAY INSTRUMENT 129

both the no on-orbit storage and the data storage options open while I examined the feasibility of an onboard data recorder. By early May, I was convinced that in-orbit storage was technically achievable, and we committed ourselves to that approach.

As events unfolded, both configurations were ultimately employed, with Explorer I being made as simple as possible with no on-orbit storage. It was followed by the unsuccessful Explorer II and the fully successful Explorer III, both of which carried the onboard storage device. The presence of onboard storage in Explorer III proved to be a critical element in interpreting the unexpectedly high counting rates encountered by the pathfinder Explorer I and was, therefore, a major factor in the discovery of the Earth’s radiation belts.

I began my design effort by inventorying known options, including the counting of shaft rotations, accumulating charge on a capacitor, chains of bistable scalers, magnetic matrix (core) storage, dielectric matrix storage, magnetic and dielectric tape recording, magnetic and dielectric drum recording, magnetic wire recording, cathode ray tube storage, and mercury tank storage. The latter two were discarded outright. By 7 May, I had narrowed the viable possibilities to magnetic drum, magnetic tape, ferroelectric matrix, ferromagnetic matrix, and capacitor bank storage. Two days later, I decided to proceed with magnetic drum storage.

The data storage device eventually passed through four major design phases. The first model, Mark I, was the drum recorder. The Mark II, III, and IV models, all based on magnetic tape storage, incorporated a number of progressive improvements. Mark II used Mylar tape and a mechanical centrifugal governor for controlling the playback speed. For Mark III, metal tape, a magnetic field-eddy current speed control mechanism, and an improved tape advancing mechanism were substituted. The final Mark IV design incorporated a further-improved tape-advancing mechanism.

Today the circuitry on a small fraction of a square millimeter of a solid-state memory chip would provide the same functionality as the Explorer III tape recorder. But that was before the age of integrated circuits, and the only practicable approach was to develop an electromechanical device.

The third major challenge was in miniaturization. Because of the extreme constraints in satellite size and weight, we needed a much more compact method of assembling our electronic components than we had used for the vacuum tube circuits in the balloons and rockoons. Single – and dual-layer printed circuit boards were state of the art in 1956—the Naval Research Laboratory (NRL) and the Jet Propulsion Laboratory (JPL) engineers were using them routinely, and they looked promising for our work. However, there were no facilities for producing them in the Iowa City area. I purchased the necessary supplies, set up a trial printed circuit facility, and produced a few boards to check out the techniques.

Their quality was poor. I turned to an alternate process using terminals that were pressed, or swaged, into holes drilled in fiberglass circuit boards. The component

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leads and other interconnecting wires were wound around the heads of the terminals and soldered in place. Although inelegant, that approach proved to be rugged and reliable, and the circuit boards could be assembled wholly within our laboratory by student aides.

The Jet Propulsion Laboratory’s director, William H. Pickering, played a central role in reshaping the organization’s direction at the beginning of the Space Era. Born in New Zealand in 1910, William H. Pickering was attracted to CalTech by an uncle. There, he took his bachelor’s and master’s degrees in electrical engineering. He received his Ph. D. in physics in 1936 and stayed on as a faculty member in electrical engineering. His graduate and postgraduate work put him in touch with the work of CalTech’s Robert A. Millikan and Victor Neher, whose seminal work in cosmic ray research especially caught his interest.

In 1944, he began part-time work at CalTech’s JPL, organizing their electronics efforts to support their guided missile research and development. He became project manager for Corporal, the first operational missile that JPL developed. During Corporal testing at White

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Sands, Pickering became aware of the work of von Braun’s group on the V-2, and the two groups collaborated to launch a series of combined V-2-WAC Corporal two-stage vehicles known as the Bumper-WAC. One of its flights reached a record altitude of 244 miles in February 1949, becoming the first man-made object to reach extraterrestrial space.

During that period, Pickering broadened his interest in scientific research and its special demands on technology, including serving on several national committees that were active in charting upper atmospheric research. He shifted from part-time to full-time work at JPL in 1950. From then on, although retaining the rank of full professor on the campus, the JPL work took most of his attention. He took over as the JPL director in the fall of 1954.

In his discussions with California Institute of Technology president Lee DuBridge, the new director agreed that JPL should begin thinking of a shift away from classified missile development to something that was more compatible with the open research character of university research. The Sergeant missile program had been authorized shortly before Pick­ering’s assumption of the JPL leadership—he and DuBridge agreed that it would be their last army missile program.35

In September 1955, upon returning to Pasadena from Huntsville from the von Braun discussion following the Vanguard decision, Froehlich placed the remaining scaled-Sergeant rockets in a “long-term life test.” It was explained to me after I went to JPL much later, that, although the ABMA and JPL had been instructed from Wash­ington to stop all work on the remaining Jupiter C rockets, they did obtain permission to use them in “technology tests.” The tests were characterized tongue-in-cheek as “placing the spare rockets in storage at normal room temperature and pressure until destroyed.” Through that stratagem, the upper-stage rockets were preserved for later use in the satellite program.

From the time of the discussion at Huntsville in September 1955 through the time of the third RTV flight in September 1957, JPL carried the project responsibility for three major RTV tasks: (1) adaptation of the scaled-Sergeant rockets for that purpose, (2) development of the cluster arrangement to form the upper stages of the vehicle, and (3) development of a telemetry system for relaying flight performance data to the ground.

The first two tasks, adaptation of the scaled-Sergeant rockets and development of the upper stage cluster, required the combined efforts of teams of mechani­cal engineers, materials specialists, and propulsion experts. They configured the rocket’s thrust chamber and developed a suitable ignition mechanism. Under Geoffrey Robillard’s leadership, they loaded and fired enough test rockets to determine the op­timum fuel and chamber configurations and to establish the rocket’s reliability. As for the mechanical configuration of the cluster, under John Small’s leadership, they determined the number of stages required, made the weight analyses, designed the mechanical configuration, and performed mathematical analyses of the structural design and in-flight performance. As already stated, the work was done in such a way that a live fourth stage with its satellite payload could easily be added to the cluster.

CHAPTER 7 • THE U. S. SATELLITE COMPETITION 203

The third JPL area of responsibility was to develop a suitable tracking and data telemetry system to assist in obtaining engineering data from the RTV final stages. That might have been quite simple if the system were designed exclusively for that purpose. Those flights were of short duration, so long-lasting batteries were not nec­essary. The RTV rocket configuration had sufficient weight-carrying capability that more conventional flight components, including vacuum tubes, could have been used. The higher weight-carrying capability also meant that much higher-powered trans­mitters could be used, obviating the need for a supersensitive tracking and telemetry system.

However, from the very beginning, the JPL engineers wanted the system to be usable in a satellite. Initial ideas for what became the future Microlock system had been developed while JPL was designing the Corporal missile. When JPL was brought into the Orbiter program planning by the Huntsville and navy teams in the fall of 1954, the long-range possibilities for such a system became even clearer in their minds, and the Microlock system began to take more tangible form. A look at the Microlock development emphasizes the extent to which it was shaped by their dreams of space flight.

One of the leaders in the Microlock development was a new engineer, Henry L. Richter. He figured prominently in the application of that system to the satellite program and in the preparation of the Jupiter C satellite instruments.

Henry holds a special place in my memory as my primary contact and close friend during the five months that I was at JPL during late 1957 and early 1958.

ven while the Deal I satellite (Explorer I) was being assembled, work was moving forward steadily on the Deal II payload. While Deal I used only the Geiger-Muller (GM) counter, high-voltage power supply, and scaling circuits from my Vanguard design, the Deal II package contained my complete University of Iowa instrument, including its onboard data recorder.

Building the Deal II instruments

Only days before leaving Iowa City for Pasadena in November, I had finished con­structing the engineering test model but had not had time to draw the final detailed schematic diagrams. They existed only in scattered notes in my notebook and in my mind.

When I drove from Iowa City to Pasadena, the trunk of our car carried those notebooks, the engineering prototype package, and the parts that I had already begun accumulating for the flight instruments. Figure 10.1 shows the prototype Vanguard package as it appeared at that time.

The overall configuration of the Jupiter C version had been worked out through our exchanges in late October and early November. Although the outward appearance of the complete Deal II satellite was markedly different from that of the Vanguard satel­lite (a long cylinder rather than a sphere, as shown in Figure 10.2), the internal canister housing the University of Iowa cosmic ray instrument was quite similar. Some idea of that resemblance is seen by comparing the Vanguard instrument package in Fig­ure 10.1 with what became the Explorer II instrument cylinder shown in Fig­ure 10.4. The primary differences were (1) substitution of a JPL-designed high-power

263

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transmitter for the Naval Research Laboratory (NRL)-designed one, (2) changes to the NRL command receiver made necessary by the change to the two-transmitter (Minitrack plus Microlock) configuration, and (3) a change in electromechanical component locations necessitated by the higher spin rate.

Several tasks were especially pressing when I arrived at the Jet Propulsion Laboratory’s (JPL’s) gate. The first was to provide a catalog of needed parts. I completed a four-page list and turned it over to the JPL engineers on 4 December. They immediately placed a stack of rush procurement orders.

My second major task was to furnish workable schematic diagrams of my electron­ics design, which I drew by hand from the many sketches and notes in my laboratory notebooks. Most of those drawings were handed over to the JPL engineers by 16 December. However, I was still uneasy about a few of the tape recorder control circuit details. The engineers in JPL’s circuit development laboratory helped me with improv­ing those, and I eventually turned over the final schematic diagram on 9 January 1958.

Another urgent initial task was to arrange for the completion and installation of the onboard tape recorders. The tape recorder was unique—no comparable unit

CHAPTER 10 • DEAL II AND EXPLORERS II AND III

SUB CARRIER OSCILLATORS

AND

I KANSMITT ER ВАТТ ERIES

LOW POWER ANT GAP

AND TRANSMITTER

G M COUNTER

INSTRUMENTATION CYLINDER

COMMAND RECEIVER

PLAYBACK TRANSMITER

COSMIC RAY EXPERIMENT

ELECTRONICS

BATTERIES

>- TAPE RECORDER

HIGH POWER ANT GAP ■ROCKET CASING

FIGURE 10.2 The Deal II satellite. The six inch diameter instrumentation cylinder at the center of the figure contained the Iowa cosmic ray instrument.

was available from industry, and it would have taken too long for JPL to tool up to produce them. It was agreed that the instrument makers at Iowa, primarily Ed Freund, would complete the manufacture of four flight tape recorders. They would be shipped, however, with one task remaining undone. Ed had just completed the design of a new solenoid mounting bracket that converted the units from the Mark III to the Mark IV design, but had not yet machined enough for the flight units. We agreed that time would be saved if JPL machined the remaining mounts and installed the solenoids on them.

OPENING SPACE RESEARCH

On 26 November, I turned over the first completed recorder to Bob Garwood for him to begin making the modification. The second flight tape recorder arrived from Iowa on 5 December, and the others arrived at about one week intervals.

Also on 26 November, an engineer in Henry’s lab reported that he had been able to operate all of the Vanguard electronic circuitry in my prototype instrument package.

The JPL engineers had not been involved in designing the circuits in my cosmic ray package and had not had a hand in testing the components that I had selected. They established their own confidence in my work by building laboratory breadboard copies of many of the circuits and putting them through various tests. In only a few cases did they make minor changes.

We all shared a special concern about the performance of the onboard tape recorder in the more stressful environment of the Jupiter C launch vehicle. We were also anxious to verify the electronics packaging techniques that I had used. Although similar to those being used within the Vanguard project, some of the techniques were new to the JPL engineers.

Thus, we prepared a series of early vibration and spin tests using the Vanguard engineering design instrument package.[4] The JPL technicians mounted a new GM counter on my package to replace one that had been broken and installed a different turn-on plug on the top cover. We made the Mark IV modifications to the tape recorder and installed it in the package. Finally, we updated the wiring between the electronics decks.

They prepared a special mounting jig to attach the instrument package to the spin test facility. The initial results were encouraging. Everything, including playback initiated by the command transmitter and receiver, was normal up to a spin rate of 500 revolutions per minute (rpm). However, above that rate, recorder playback could not be reliably commanded. We were not sure whether the problem was in the tape recorder, in its control relays, or in interference to the radio frequency command signal caused by the noisy laboratory environment.

Milt Brockman suggested mounting a temporary test switch on top of the GM counter to bypass the command and control relays, in such a way that that switch could be actuated while the instrument was spinning. The engineers set up that ar­rangement overnight, and the next day, we made another spin test. The spin rate was increased to 1000 rpm, and operation was satisfactory. We then reconnected the playback relay, relocating it so that it was closer to the spin axis. During the next test, recorder playback was satisfactory up to 1100 rpm, but not at 1250 rpm. We concluded that the problem was with the relay, but we decided to proceed with it that way because the maximum spin rate during and after launch would be much lower at 750 rpm. The spin test series ended with a run with all of the sensitive

CHAPTER 10 • DEAL II AND EXPLORERS II AND III 267

components mounted in the positions envisioned for flight. That arrangement op­erated satisfactorily at 1190 rpm, but not at 1250 rpm. Again, we considered it acceptable.

A series of vibration tests of the cosmic ray package was uneventful. With the results of those vibration and spin tests in hand, I sketched the final internal physical arrangement for the Deal II cosmic ray instrument package on 9 December.2

Although the changes in the satellite program had substantially delayed my university course work, the objective of obtaining my M. S. degree was never far from my mind. Van Allen and I discussed that subject during several of our telephone discussions in early December, and he sent me a sample of a master’s thesis based on the development of another cosmic ray instrument. That helped me develop a feeling for the writing that I would have to do and provided additional motivation for very meticulous note taking.

A pivotal instrument review and planning meeting was called by payload manager Walt Victor for 11 December. Specific individuals were assigned responsibility for various portions of the work. The schedule called for the first flight unit to be shipped to Cape Canaveral on 10 February, with shipment of the second payload on 17 February. To make that schedule, the first State University of Iowa (SUI) cosmic ray package would have to be fully assembled and tested by 11 January, only one month hence, and the second unit would be required one week later.

That meeting served as the “starting gun” for the actual fabrication of the hardware. Following the meeting, Walt issued an “all hands” memo that began:

There is no pad in the Deal II schedule. All flight hardware must be completed on time and must operate satisfactorily in the environment [emphasis his]. It is suggested that all engineers consider the scheduled date as the absolute latest time the equipment can be made available, and that they make every effort to better the scheduled date whenever possible. I will be following the work progress very closely and expect to be notified immediately of any circumstances which would prevent making the schedule.3 I

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During much of January 1958, aside from my work on the GM counter calibrations, as recounted earlier, much of my effort went toward finishing and testing several of the Deal II circuits. In mid-January, a few design details on the tape recorder playback amplifier and relay control circuits were still being improved. One of those improvements was to add a protective circuit to unlatch the control relays in case the recorder should freeze, so that the batteries would not be drained if that should occur. My summary report to Van Allen on 20 January read:

Needless to say, all circuits which were not completely checked out when I left Iowa have now been. The recorder drive circuit [had not been], but has been found by now to operate from —25°C to +65° The playback amplifier required some rework, and now utilizes considerable negative feedback to stabilize its operating conditions. Its characteristics change very little from —25°C to +75°C. It delivers a saturated rectangular pulse to the modulator.4

That letter included a set of drawings for both the Deal I and II instrument packages, a five-page listing of all of the components being used in the flight payloads, and their selection criteria. I promised to send mechanical drawings in the near future.

I also reported:

My schedule is finalized now—will leave here the 26th, leave there [Cape Canaveral, not mentioned because of security] the 31st, arrive Iowa City the 31st at 2:05 PM, and leave Iowa City the 3rd at 2:15 PM. Had the thought that you might not be back in Iowa City by the 31st.

If not, will you send a wire? Also need the address at which I can contact you in Washington and your itinerary if possible.5

As mentioned earlier, I delayed my departure to Cape Canaveral for the Deal I launch until 28 January to make additional tests of the GM counter calibration setup and procedures. Even after those tests, I still had some reservations about the final calibrations. Beginning on 14 February, after I had returned from the Explorer I launch and my stop in Iowa City, I made a detailed assessment of the entire calibration setup, procedures, and results. After four days of work, I finally convinced myself that the calibrations were valid.6 I would have preferred to give the counters on the Deal II flight units a final run, but by that time, the first unit was already at the Cape. Any lingering concerns were not sufficient to warrant interfering with the remaining launch preparations.

By the end of Tuesday, 18 February, my work on Deal II appeared to be essentially complete, and it looked like I would be able to spend a few days at home with Rosalie and the two girls. My journal reported:

Payload I is built. It was recently pared down to remove weight, but is rebuilt. # II [the second payload for Deal II] is being built. There were three difficulties so far. (1) An internal short in receiver deck B2 caused a 150 ma. [milliampere] drain. Cleared OK. (2) Tuning fork deck D2 became intermittent. Replaced with D3. (3) This afternoon before leaving found out the playback head in recorder J2 was not delivering sufficient pulse amplitude. This will require disassembly & checking.7

CHAPTER 10 • DEAL II AND EXPLORERS II AND III 269

That marked the end of the payload development and assembly. During a long phone conversation with Van Allen on that day, we discussed many topics, including plans for preliminary analysis of the Explorer I data and for the upcoming Deal II satellite.

At the Cape, the JPL engineers were making several rather substantial last-minute modifications to the first Deal II flight payload mechanical structure. That included the substitution of a shorter shell, a lighter magnesium instrument container, and a lighter fretwork support for the low-power transmitter assembly. There was still considerable concern about achieving a sufficiently high orbit with a payload that was somewhat heavier than Explorer I, and every step imaginable was taken to reduce its weight. The other two Deal II flight payloads were modified in similar fashion at JPL before they were shipped to the Cape.

My brief respite was short-lived. On the 19th, two developments put me back into the crisis mode. The first was a failure during the environmental testing of the spare flight payload (the third Deal II payload). The recording amplifier quit operating, and the instrument would not respond to interrogations during the vacuum chamber test. After I analyzed the problem the next morning, the JPL engineers set about to repair it.

I turned my attention to the second crisis, the lack of readiness of the ground stations that would be needed to interrogate the satellite’s tape recorder. That problem is discussed in the next chapter.

Ernest C. Ray, or Ernie, as all his associates knew him, was born on 23 February 1930 in St. Joseph, Missouri, and he grew up in that city as a bright youth in a stimulating household. In high school, he was in the marching band as a clarinetist, in theater, and unusually active in the Boy Scouts, where he attained the rank of Eagle Scout.

Following high school, Ernie began his college work at Saint Joseph Junior College. Since he had settled upon physics as his primary academic interest, and as Saint Joseph did not offer a physics curriculum, he moved to the University of Iowa after his second year at St. Joseph. He received his B. A. degree in the fall of 1949. He continued there for all of his graduate work, receiving his M. S. and Ph. D. degrees in 1953 and 1956, respectively.

During his graduate study years, Ernie served several stints at Princeton University, New Jersey, working on the Matterhorn nuclear fusion project. Throughout his years at Iowa, he made major contributions to the research program through his study of, and keen insight into, physics and, particularly, the motions of charged particles in the near-Earth region.

Following receipt of his Ph. D. degree, Van Allen offered him a series of faculty positions, first as an instructor, then as an assistant professor. He remained there until June 1961, when

CHAPTER 12 • DISCOVERY OF THE TRAPPED RADIATION

he took a short appointment at the RAND Corporation at Santa Monica, California. In early 1962, he joined the research staff at NASA’s Goddard Space Flight Center. Moving for a year and a half to Cornell University in Ithaca, New York, he returned to Goddard in early 1965.

By that time, his friends noted a marked personality change. His creative contributions to Goddard’s research waned, he stopped publishing, and it became increasingly difficult to converse with him. His descent into the depths of acute schizophrenia continued to the point that he was committed to a mental health institution in 1970. He remained there, in halfway houses, and in other transitional facilities for the rest of his life. In his later years, he became a valued volunteer at the Baltimore Fellowship of Lights, an organization that provides assistance for runaway youths and their families. In that environment, he managed to maintain his dignity and live a useful life until he died, in December 1989, of kidney cancer and chronic lung disease.

With the failure of the Explorer V launch and the NOTSNIK attempts, the Argus Project was left with only Explorer IV to obtain the crucial orbital data coverage. Fortunately, the satellite operated perfectly for nearly two months, from 26 July until 21 September, well after the Argus detonations.

It was important to obtain data from the full range of latitudes covered by the satellite for both an expanded study of the naturally occurring radiation, and for detecting and measuring the Argus Effects. The full suite of Minitrack stations es­tablished earlier as part of the Vanguard program was used. Additional stations were set up to extend the orbital coverage and, most important, to provide coverage at the higher latitudes. The full suite of stations used for Explorer IV data reception was impressive:

The initial month’s data from Explorer IV established the natural conditions in the Earth’s radiation trapping region and showed rather small responses to the lower- altitude Teak and Orange bursts on 1 and 12 August. When the first Argus nuclear device was detonated on 27 August, the satellite easily and promptly detected the

OPENING SPACE RESEARCH

resulting particle shell and did likewise for the two bursts that followed on 30 August and 6 September.

On 24 August 1958, the day after the Explorer V attempt, I was feeling completely worn out and swamped by the work ahead. Work was progressing on PL-16 (the precursor to Explorer 7); planning for a number of lunar probes was heating up; and I was heavily involved in the Explorer I, III, and IV data reduction. Additional missions were being discussed. On top of that, Van Allen was on vacation on Long Island, so I had only infrequent telephone contact with him to resolve issues. A new academic semester was about to start. I had not been taking courses for most of the year and was very concerned about completing the work for my master’s and Ph. D. degrees. On that day, I expressed some of those concerns by writing in my journal:

The future is confusing, and a big question mark. At least four projects can be seen in the near future, with no sign of a letup. This in view of the fact that I planned to return to school this fall. I can hardly bear to think of not obtaining my Ph. D., yet, how can I escape from this other work. My family is another consideration. I have been away from them so much the past year, … I cannot continue to spend one hour per day or less with my family and expect to have a livable home relationship and happy, well-adjusted children.17

That difficulty was resolved to a satisfactory degree at the end of the month. By then, Van Allen had returned to the campus and he, Carl McIlwain, and I were able to sit down for an extended discussion of the laboratory’s space-related work. At that meeting, I stated that I would be unable to continue the combination of the heavy instrument development and management load that I had been carrying, plus the work on the data and an academic load. We agreed to limit our total laboratory efforts to three major project series and to split them up among us. I would continue with the Explorer activities, Carl would take the Space Technology Laboratories’ lunar shots (Atlas-Able and Pioneers 1 and 2), and Van Allen would take the JPL lunar shots (Pioneers 3 and 4).18

I promptly signed up for courses in Classical Theoretical Physics and Nuclear Physics.

The decade of the 1950s was marked by an unusually good spirit of cooperation among the scientists who participated in the Great Space Endeavor. It was furthered by the spirit of common purpose and cooperation engendered by the IGY.

I was greatly impressed by the proceedings at the pivotal meeting of the Upper Atmosphere Rocket Research Panel at Ann Arbor in early 1956. The summer before, the president had announced the goal of orbiting an artificial Earth satellite as part of the U. S. participation in the IGY. That presented a wonderful opportunity for many scientists to realize their long-standing dream: to observe our earthly home from well above the atmosphere.

One would have to admit that the possibility of participating in that grand adventure might have engendered a fierce competition with many negative aspects. That did not happen. Never once did I observe an instance of a scientist trying to gain a

OPENING SPACE RESEARCH

foothold by attacking a potential competitor. The competition was marked by efforts by prospective participants to convince their research colleagues of the validity and superiority of their own ideas. When decisions were made, one way or the other, there was a willingness to proceed on that basis, with a minimum of backbiting and other destructive behavior. Never, throughout the entire period leading up to and including the IGY, did I observe a substantial instance of untoward selfishness, destructive competitiveness, or power brokering among the many established and emerging scientists with whom I was in contact.

The “let’s get on with the job” spirit enabled many amazing accomplishments. Excep­tionally short development times were possible that astound those looking back from the present vantage point. Explorer IV was planned, approved, and launched within a period of 77 days.

The spirit of the 1950s made it possible for individual graduate students to conceive of experiments, build the instruments, launch them into space, collect and analyze the data, and publish results during the few years of their university studies. Although that form of end-to-end experience can still be gained today with some balloon and rocket studies, it is rare with most of the current, more ambitious space experiments.

It takes years and even decades to develop some of today’s instruments. A large share of the difference must, of course, be attributed to the vastly different scale and complexity of the experiments. It is an inescapable result of the maturing and broadening of the field. As a result, today’s far grander instruments are bringing us a cornucopia of spectacularly beautiful and important revelations about the nature of the universe that could not otherwise be gained.

Despite today’s great capabilities, there remains a persistent longing by many of us “old-timers” for the relative flexibility and freedom that we enjoyed in that bygone era. The pressures during the 1950s were great, and we worked long hours, but it was a period of tremendous excitement and achievement.

For any researcher, and especially for a student, an environment in which the full spirit of the Sigma Xi motto “Companions in Zealous Research” prevails is a true blessing. Many of us benefited tremendously from that environment during those early years of the Space Age.