Category Dreams, Technology, and Scientific Discovery

y the fall of 1952, all of the essential elements were in place at the Iowa Physics Department for a sustained program of upper atmospheric research. There was outstanding leadership, a capable staff, a cadre of eager students, appropriate tools and techniques, experience with field operations, and modest funding. Early scientific re­sults were appearing in print. James Van Allen and his new group were already solidly established in the national and international science arena as leading contributors to cosmic ray research.

Entering opportunity’s door

Purely by chance, I arrived on the scene at about that time. When my tour of active duty with the Air Force ended on 18 December 1952, I returned to my Iowa family home near the tiny town of Tiffin, located just eight miles west of Iowa City. My single-minded goal was to enter the University of Iowa to study physics. With no understanding of the significance of the situation that was developing at the time, a tremendous opportunity was opening.

For a number of years my father, George M. (GM) Ludwig, conducted a daily morning program over local radio station KXIC from his Ludwigheim farm home. He had interviewed Van Allen, Meredith, and Blodgett in October upon their return from the summer’s rockoon expedition. Van Allen and Meredith returned for a follow-up interview a few days after I arrived home. In the course of that morning’s discussions, Dad (acting as my self-appointed agent) turned to Van Allen and asked, “George is just back from the Air Force and is looking for a job. Might you have something for him?” Van Allen replied that he might and suggested that I come to his office the following Monday to pursue the question further. I did so, and he offered me part-time

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work as a research aide in his Cosmic Ray Laboratory, at 75 cents per hour. I eagerly accepted his offer, began work immediately, and was well established there when the spring semester opened in February 1953.

Anderson’s 1957 Fort Churchill expedition As Kinsey Anderson was arriving in Iowa City in September 1955, our summer rockoon expedition was returning with new information about the auroral soft radiation. When Kinsey saw those results, he noted that the anomalous radiation was occasionally penetrating to altitudes lower than the rockets’ peak altitudes. In fact, the auroral soft radiation was sometimes seen at altitudes that might be reachable directly by Skyhook balloons. He believed that balloon flights, flown for extended periods of 10 to 30 hours at their peak altitudes, might be able to capture synoptic and time variation information on both the auroral soft radiation and low-energy cosmic rays that was not obtainable from the relatively short duration rockoon flights.

Kinsey had been impressed by a seminar at Minnesota in late 1954, in which Phyllis Freier described a potential IGY project for studying cosmic ray variations. She suggested that a series of balloon launches covering an extended period carry a standard set of cosmic ray particle detectors to study those variations.

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Those two lines of thought converged, prompting Kinsey to submit a proposal to the U. S. National Committee for the IGY in November 1955. It called for a large number of high-altitude, long-duration balloon flights to be carried out during 1957 at Fort Churchill, Canada, a site well within the auroral oval.14

Kinsey immediately began designing an instrument to achieve that objective. It in­cluded three basic detectors: (1) a GM counter telescope, (2) a single GM counter, and (3) a scintillation detector using a thallium-activated sodium iodide crystal mounted on the front of a photomultiplier tube. The scintillation detector was configured to have high efficiency for X-ray radiation at energies above about 10 keV He expected the combination of instruments to reveal new information about the energy spectrum of the parent electrons that were responsible for the auroras.

However, Kinsey ran into serious problems in moving his project forward. To begin with, rules at the University of Iowa at that time did not permit junior researchers to submit proposals to outside agencies. Van Allen stepped in to sidestep that hurdle. The next step was to gain U. S. and IGY programmatic and financial support. In late 1955, Homer Newell’s Special Committee for the IGY (operating under the umbrella of the U. S. Upper Atmosphere Rocket Research Panel) reviewed his proposal and rejected it, apparently through some misunderstanding between Kinsey and the committee. Newell went so far as to declare that, beyond the funding issue, the U. S. military support group at Fort Churchill would not be permitted to support it.

Kinsey then attempted to obtain funding via the National Academy’s Technical Panel on Rocketry for the IGY. Scott E. Forbush, as its chairman, explained that nearly all of their funds for U. S. IGY cosmic ray research had already been committed. He asked if $15,000 would permit a useful program (compared with the $60,000 that Kinsey had requested). The panel also stated that, if approved, Kinsey would have to switch to a substantially different detector complement, to bring it more in line with programs at other locations that had already been approved. Specifically, it would have to include two instruments like those being used by the Minnesota group: a 10 inch diameter Neher-type integrating ionization chamber and their single GM counter design. Under those conditions, it would not be possible for Kinsey to in­clude the envisioned scintillation detector, and the nature of the project would be substantially different than originally envisioned.

Nevertheless, Kinsey quickly replied that he would be able to achieve meaningful results with that arrangement and submitted a revised proposal for the new instruments and a reduced number of flights. That resulted in approval for the modified program in April 1956.

Even then, the way was not clear. Newell had forbidden support by the U. S. military support at Fort Churchill, so other arrangements had to be made for launch­ing the balloons. Acting on Van Allen’s suggestion that he contact Donald C. Rose

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of the Canadian National Research Council, the problem was eventually resolved when Kinsey’s program was made part of the joint Canadian-U. S. IGY program, with Canada taking responsibility for the launches. Kinsey later reported that the arrangement with the Canadians turned out to be a very happy and productive one.

Developing the new instruments presented another major challenge to Kinsey, as he had no previous experience with ion chambers. With help from several students, and benefiting from the instrument shop’s much-earlier experience with Bob Ellis’ ion chambers (described in the first chapter), he prepared the instruments during 1956 and the first half of 1957. The spherical chambers had to be designed, manufac­tured, and assembled, and then they had to be baked out, evacuated, filled with argon gas, and calibrated (Figure 4.3). And the GM counters and various associated elec­tronics had to be designed and built. Completing the work was touch-and-go, and the last few ion chambers were completed only days before the first scheduled balloon launch.

With the various delays, final approval for the flights was not obtained until April 1957, only 10 weeks before the field operation was to begin. The schedule was met, however, and between 7 August and 7 September 1957, Kinsey, with help from three undergraduate students, directed the launch of 14 of his balloons from Fort Churchill. In total, they obtained about 175 hours of data from altitudes above 18 miles.

Kinsey related a fascinating tale about a highly improbable event that occurred during their field operation. In his words:

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The program of IGY balloon launches in 1957 was punctuated by a remarkable coincidence in space, time, and people. After we had launched a balloon on 7 August, we hurriedly loaded the inflation gear into the panel truck and sped toward the main base and our telemetry station. The road closely paralleled the western shore of Hudson Bay. Glancing eastward over the Bay I saw a polyethylene research balloon coming out of a low-lying cloud layer. The balloon we had just launched had moved rapidly westward and away from Hudson Bay only a few minutes before. The intruder collapsed onto the rocky beach. We stopped the truck, started the Homelite generator, and snapped on our checkout telemetry receiver. We were indeed still receiving the VHF telemetry signal from our balloon off to the west. I then guessed that the interloper had to be a balloon used by the SUI group launching Rockoons in the Davis Strait half a continent away to the East. Running to the beach where the balloon lay partly in the water and partly on the beach, I chopped off the end portions with the hunting knife I carried (most persons engaged in launching large balloons carried such a knife believing it might save their life should they become fouled in a line as the balloon was released). When we returned to Iowa City, I showed the balloon ends to Laurence Cahill who verified they were from a balloon of the type used that summer for the Rockoon launches.15

Although most of Kinsey’s flights provided interesting and useful data, the one on 29 August 1957 was especially noteworthy. A Forbush decrease in cosmic ray intensity marking the beginning of a geomagnetic storm was detected by monitors at numerous ground locations while the balloon flight was in progress. The cosmic ray decrease at flight altitude was about twice as large as that observed on the ground. Although soft radiation (X-ray) was seen frequently throughout the flight, a strong burst of X-rays lasting about five minutes was seen in the balloon’s instrument at a time coinciding with the beginning of the storm. Ground observers reported that they had seen bright and active visible auroral during the period of observation. That was one of the earliest cases where the direct effect of energetic particles (electrons) was associated with such a geomagnetic phenomenon.

During flights on several other nights when quiet auroral arcs appeared in the sky, no similar X-rays were seen by the balloon instruments. This led to Kinsey’s inference that the quiet arc type of aurora did not involve electrons having energies high enough to produce X-rays that could penetrate that deeply into the atmosphere.16

Returning to Fort Churchill in 1958 Following up on his 1957 success, Kinsey proposed a series of balloon flights for August-September 1958 to further study the auroral zone radiation. Again, the balloons were to be launched from Fort Churchill. Approval was much more straightforward for that proposal—he submitted it to the U. S. National Committee for the IGY in October 1957, and it was approved relatively quickly.

Assisted by Donald Enemark, they made substantial improvements in the instru­ment design. They improved the low-temperature performance of transistor ampli­fying and scaling circuits, and the weight of the package was reduced by replacing the vacuum tube transmitter with one employing silicon transistors. In August, the

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two, joined by students Donald Stilwell and Louis Hinton, made their way to Fort Churchill with their instruments.

During the August-September 1958 period, they made 10 balloon flights, col­lecting 150 hours of high-altitude data. Kinsey’s account of the launch operations provides interesting reading.17 It tells of launches made during windy conditions from locations ranging from the leeward side of an aircraft hangar to the playground of the Fort Churchill elementary school, where many eager young faces watched from the windows. The flights produced varying results, with some indicating only quiet-time background cosmic radiation, while others showed moderate auroral X-ray activity.

The flight launched at about 8:30 local time the evening of 21 August was more exciting. By 10:30, the balloon had settled at its float altitude. Throughout the night, the counting rates were monotonously constant, revealing only the presence of the normal background cosmic rays. They were sufficiently uninteresting that Kinsey felt comfortable in catching a few hours’ sleep. After breakfast, he returned to the receiving station to find the situation unchanged. However, at about 9:45 on the morning of 22 August, things changed dramatically. The pen movements on the data recorder began to speed up—over several minutes, the rates climbed to previously unseen levels. All detectors were vigorously responding to some form of ionizing radiation. In Kinsey’s words:

I was especially struck by the rapid pulse rate of the usually sluggish ionization chamber.

Ionizing radiation was reaching the balloon at intensities far beyond anything that we had encountered on any previous flight. Recovering my composure, I began to think about what the detector responses were telling us. Careful study of the data received to that point convinced Donald Enemark and me that there were no instrument malfunctions. The ratio of the ion chamber to single counter response was much higher than could be produced by X-rays or gamma rays; therefore, the ionizing radiation could not be due to auroral associated X-rays.

The most powerful information for identifying the ionizing radiation came from the ion chamber-to-counter telescope ratio. That ratio told me the ionizing radiation could not be electrons, alpha particles, or heavier atomic nuclei. The measured ratio was just what I expected from fluxes of protons. After our return to Iowa City, I rechecked calibrations and made more detailed calculations and found the average energy of the protons arriving at our balloon over Fort Churchill, on 22 August 1958 to be 170 MeV.18

A highly varying pattern evolved over the next hours. The counting rates dropped and rose over a three hour period, and then the heavily ionizing radiation began a slow but steady decline. That continued throughout the rest of the morning and afternoon. Some protons were still present, however, when the transmission from the balloon ceased at about 5:00 in the afternoon of 22 August.

The team soon learned that an intense burst of radio noise was emitted from the Sun starting at about 8:15 AM, about 90 minutes before the protons were seen by the

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balloon instruments. They also learned that a great solar flare had been observed to begin about 75 minutes before the proton arrival.

That event did not produce a measurable effect in ground neutron monitors, as did some other rather rare superflares, like the one that occurred on 23 February 1956. It was clear that the proton energies were too low for either the primary or the secondary particles to penetrate the atmosphere and reach the ground.

From his flights and the work of others, it soon became understood that the Sun produces, in addition to the huge flares previously seen, more frequent smaller flares that emit large fluxes of protons of much lower energies than those produced by the large ones. This new knowledge played an important role in the evolution of the thinking about solar processes and solar-terrestrial relationships.

McDonald to Missouri and Minnesota On 27 June 1958, with help from aide Louis Hinton, Frank McDonald flew a two million cubic foot Skyhook balloon from Moberly, Missouri, to study latitude variations of the cosmic ray heavy nuclei and their relation to the sunspot cycle. The instruments were recovered the next day, and Frank and Louis flew immediately to International Falls in northern Minnesota to fly them again there. Those observations further extended the latitude range of Frank and Bill Webber’s earlier heavy-nuclei observations.

And Anderson back to Canada Kinsey Anderson’s final Iowa balloon-launching expedition was to Resolute, on Resolute Bay, Cornwallis Island, Canada. He chose that location because of its nearness to the Earth’s north magnetic dip pole (the location of the north magnetic dip pole is considerably removed from both the north geomagnetic pole and the north geographic pole). On that expedition, in July 1959, Kinsey, Don Enemark, and Robert Lamb launched 10 balloons into very high intensities of particles produced by large solar flares.

Balloons as a continuing feature Balloon flights by the Iowa group continued throughout the rest of the decade, both with the huge Skyhook balloons and with much smaller ones.

Balloons are still in use today, primarily to achieve long flight durations at relatively low cost. Flight capabilities have grown dramatically since the 1950s. To illustrate, a new balloon flight duration and distance record was set in early 2005. It involved a flight of nearly 42 days, during which the balloon and its instruments traveled through three orbits around the South Pole. Launched from the National Science Founda­tion’s McMurdo Station in Antarctica on 16 December 2004, it landed on 27 January 2005 after traveling 27,410 miles. The enormous balloon, weighing 4055 pounds, ex­panded to a diameter of more than 450 feet at its ceiling height of 125,000 feet (about 24 miles). The balloon carried a Cosmic Ray Energetics and Mass experiment de­signed to explore the supernova acceleration limit of cosmic rays, the relativistic gas of protons, and electrons and heavy nuclei arriving at Earth from outside the solar

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system. That flight was an early demonstration of the developmental NASA Ultra­Long Duration Balloon, which is expected to extend flight times up to 100 days.19 Balloon sizes are now up to nearly 30 million cubic feet, capable of carrying payload weights exceeding 5000 pounds.20

Summarizing the Iowa experience with balloons during the decade of the 1950s, many Iowa physics students did at least part of their research with balloon-borne instruments. At first, very small, inexpensive latex balloons were used by graduate students Leslie Meredith, Robert A. Ellis Jr., Ernest C. Ray, Kenneth E. Buttrey, William R. Webber, and Raymond F. Missert. By the end of the decade, after the Skyhooks had entered the scene, many additional researchers had used balloons. They included (in addition to the work of McDonald, Kinsey Anderson, Cahill, and McIlwain described earlier) graduate students Hugh Anderson and Ralph Tuckfield. Many of those flights contributed significant new information about radiation in and above the Earth’s atmosphere.

ife within the U. S. space program changed dramatically following the launch of the first Sputnik. The public surprise and outcry following failure of the United States to be first in space energized everyone in a way that no other event short of a war could have done. Their feat vividly demonstrated that the Soviets were capable of launching nuclear weapons over intercontinental distances. The realization that the Soviets really were ahead of us in developing large, long-range missiles resulted in a strong U. S. reaction, and the cold war race for rocket supremacy built to a feverish pitch. The pressure for the United States to get a satellite into space mounted, only adding to the frustrations of the Vanguard personnel, who were having problems in bringing their launch vehicle to a state of readiness.

No account of the early U. S. satellite program would be complete without stepping back in time to examine the fierce competition for developing the U. S. International Geophysical Year (IGY) satellite launcher, the decision to go with the Vanguard proposal, and the persistent effort to keep a losing proposal alive.

did not leave Pasadena for the Cape on 26 January 1958 as planned. I felt that I had to complete the Geiger-MUller (GM) counter calibrations for the Deal II payloads and delayed my departure until the very last minute. I finally left for Florida on Tuesday morning, 28 January 1958, staying overnight in Orlando. Early the next morning the Jet Propulsion Laboratory (JPL) office at Cape Canaveral sent a car to take me, first to Cocoa Beach for check-in at a motel on the strip, and then to Cape Canaveral.

Because of my delay, I arrived there while the first (soon aborted) Deal I countdown was already in progress. I did not view my late arrival as a serious problem, as JPL had the overall responsibility for preparing the relatively simple Deal I payload. I did arrive in time to observe the final Standard Source-Standard Distance check of the cosmic ray instrument in the Spin Test Facility before the satellite was installed atop the launch vehicle.

I had expected to be at some support facility for the countdown and launch where I could monitor my instrument’s performance. I was terribly disappointed to discover that JPL did not have any station available for me. I had no alternative but to join the crowd of general onlookers to listen to the countdown over the Cape-wide public address system.

It was agreed from the beginning that the Vanguard project would compute the orbits for the Deal satellites, as they had already been preparing to do for the Vanguard satellites. After the Deal project was approved in November 1957, tracking data from the JPL Microlock stations were added to the mix. All tracking data were sent to the IBM 704 computer in the Vanguard Computing Center by high-speed wire and radio teletype circuits.

Optical tracking stations An optical tracking system was established as a compo­nent of the U. S. Vanguard program. It drew upon two cooperating components, an acquisition group (known by the name Moonwatch) and a precision tracking group. The acquisition group drew heavily upon the services of amateur astronomers to pro­vide coarse tracking information. The precision tracking component, conceived and overseen by Fred L. Whipple at the Smithsonian Astrophysical Observatory at Cam­bridge, Massachusetts, used high-precision telescopic Baker-Nunn cameras having an unusually large aperture that were developed for the purpose.

Although the camera development was beset by several problems, the network was ready in time to support the Explorer and Vanguard programs. Precision op­tical tracking stations were located at Jupiter, Florida; Organ Pass, New Mexico; Olifansfontein, Union of South Africa; Cadiz, Spain; Mitaka, Japan; Naini Tal, In­dia; Arequipa, Peru; Shiraz, Iran; Curacao, Netherlands West Indies; Villa Dolores, Argentina; and Haleakala, Maui, Hawaii.

In retrospect, the Minitrack and Microlock networks for radio tracking worked well, and the missions probably could have been conducted without the optical tracking net­works. Nevertheless, they provided a layer of protection, using a very basic capability that had the full confidence of the program planners and scientists. Fully integrated into the computational effort at the Vanguard Orbit Computation Center, the optical data were used throughout the early Explorer and Vanguard programs and made a substantial contribution to the high accuracy achieved in tracking those satellites.

Minitrack stations As a part of the presatellite era’s Viking program, the Naval Research Laboratory (NRL) had developed a Single-Axis Phase-Comparison Angle­Tracking Unit. It served as the basis for the development, for Vanguard, of a tracking and telemetry system, known as Minitrack. Two versions of the ground station were developed, a Prime Minitrack Station and a Mark II Minitrack Station.12

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The Minitrack development depended upon the efforts of many NRL individuals, led by John T. Mengel. It included primary contributions by Roger L. Easton, David (Dave) S. Hepler, Victor (Vic) R. Simas, and Martin (Marty) J. Votaw.

All Minitrack stations produced satellite tracking information by the use of pairs of antennas and receivers along both north-south and east-west axes. The outputs of each pair of receivers were summed. When the angle to the satellite was such that its signal arrived at both antennas in phase, the summed output was twice the amplitude arriving at a single antenna. As the satellite moved so that its signal arrived at the two antennas out of phase, they canceled and the sum was zero. Thus, as the satellite made its transit over the station, the combined receiver output for each axis pair was a variable-amplitude signal, with the peaks occurring when the distance from the satellite to the antennas differed by an integral number of wavelengths.

That information was not sufficient to provide unambiguous position information, as the signals were in phase at a number of different angles. In the Prime Minitrack Stations, those ambiguities were removed by using two pairs of antennas having different spacing along each of the two axes.

The Mark II Minitrack Stations, being simpler for implementation by radio am­ateurs and other smaller groups, lacked the multiple pairs of antennas along each axis, and the receivers were much simpler. Their data were used in the Vanguard Orbit Computation Center to complement the data received from the Prime Minitrack Stations.

For reception of the telemetered data, the signals from the pairs of antennas and receivers were combined in a different manner.

The Prime Minitrack Stations also had command transmitters to trigger the play­back of data from the Deal II onboard storage system.

Prime Minitrack Stations were located as shown in the earlier Figure 11.1. Seven stations were located roughly along the seventy-fifth meridian of west longitude and were positioned so that the satellite would pass within range of at least one of them during each orbit. That basic “picket line” consisted of stations located at (from north to south) Blossom Point, Maryland (this station also served as the engineering prototype for development of the system); Fort Stewart, Georgia; Batista Field, Havana, Cuba; Paramo de Cotopaxi, Quito, Ecuador; Pampa de Ancon, Lima, Peru; Salar del Carmen, Antofagasta, Chile; and Peldehune Military Reservation, Santiago, Chile. An additional Prime Minitrack Station at Rio Hata, Republic of Panama, was planned initially, but it was decided that relocating that station at the Navy Electronics Laboratory, San Diego, would meet that need. An additional advantage of the San Diego location was that it was in a better position to receive the signal near the end of the first orbits of newly launched satellites.

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In addition to that basic picket line, Prime Minitrack Stations were positioned at Coolidge Field, Antigua, British West Indies (primarily for downrange reception immediately following launch), and at Woomera, Australia (to provide some very limited coverage in the eastern hemisphere).

Special Minitrack stations with wider antenna beams were established on May – gauana and Grand Turk islands in the British West Indies to assist in tracking the Vanguard first-stage rockets.

A Minitrack station was established by the National Telecommunications Research Center near Johannesburg, South Africa. The primary motivation for that station was to obtain tracking information following injection of Vanguard satellites. It provided valuable tracking information for the Explorer I and III satellites but was not called upon for telemetry data recovery.

Microlock stations As mentioned earlier, JPL had developed a high-performance tracking and telemetry system as a part of their work in testing the Corporal and Sergeant missiles at the White Sands Missile Range in the early 1950s. It operated at very low signal levels (thus, over very long distances), in spite of Doppler shifting of the frequencies of signals received from rapidly moving rockets. That Microlock system was the product of a very energetic and dedicated team under the leadership of JPL’s Eberhardt (Eb) Rechtin. His team included Richard Jaffe, Robertson (Bob) C. Stevens, and Walter (Walt) Victor.13

The Microlock system was sufficiently mature by 1954 that it was introduced into the JPL and Army Ballistic Missile Agency (ABMA) collaborative planning for project Orbiter. Following the end of all officially sanctioned Orbiter planning, the Microlock system remained an integral part of the behind-the-scenes planning for a satellite by ABMA and JPL.

The Microlock receiver was designed with an extremely narrow (10 hertz) radio frequency bandwidth. It employed a phase-locked-loop technique to track the arriving signal’s frequency. For tracking the motion of the satellites, multiple receivers and antennas used the interferometer principle in a manner similar to that described above for the Minitrack system.

A Microlock station was set up at PAFB, Florida, for checking the payloads at Cape Canaveral and for receiving data during their launches. Additional stations were located in Pasadena, California (the developmental station at the JPL home location); Temple City, California (by an amateur radio club, as discussed below); Earthquake Valley, California (at an exceptionally radiation-quiet location); and at Ibadan, Nigeria, and Singapore (for improved global coverage). The locations of the Microlock stations are also indicated in the map of Figure 11.1.

Conventional stations Some early satellite receiving stations were designed in a more conventional manner. The most notable of those was a station established

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and operated by the Radio Research Laboratories at Kokubunji, Tokyo. Although not equipped to provide tracking data, it contributed valuable eastern hemisphere telemetry data throughout the Explorer I and III operating lifetimes.

Radio amateurs Both satellite-launching nations made major efforts to enlist sup­port by the amateur radio community. In the United States, the primary medium for communicating with the amateurs was the American Radio Relay League, through its publication QST. The Soviets used their amateur radio magazine Radio for a similar purpose.

The first to appear in the United States was a pair of articles in the July 1956 issue of QST that dealt with the U. S. Vanguard program’s Minitrack system.14 They were followed over the next two years by a string of articles dealing with equipment and techniques for receiving the signals from the Vanguard satellites.

After the Microlock system entered the picture, radio amateurs were encouraged to receive its signals, as well. The San Gabriel Amateur Radio Club in Temple City, California, went so far as to build and operate a substantial station. The club’s activity was strongly supported by JPL under Henry Richter’s (W6VZA) leadership. The club obtained equipment loans and donations from a variety of sources and facilities and support from the Los Angeles Sheriff’s Department. Members of the club built much of the specialized equipment under the direction of Robert Legg (W6QYY), Lamont Shinn (W6PFR), Jack Pattison (W6POP), and Howard G. Wheeler (W6GRW). Being tightly integrated into the Primary Microlock communications network by JPL, that station provided valuable tracking and telemetered data from the early Explorer satellites. The club documented its work in a handbook that was made available to all interested radio amateurs.15

A Mark II Minitrack tracking and receiving station was established by 12 amateur radio members of the Sohio Moonbeam Group, in Cleveland, Ohio. Other radio amateurs also provided data during the early Explorer flights. Their primary value was in helping to establish the initial orbit parameters.

The Soviets, too, were eager to include radio amateurs in their program. After all, one of the primary reasons for their choice of 20 MHz and 40 MHz as transmitting frequencies for Sputnik 1 was to allow the worldwide community of radio amateurs to receive its signals. That could be done without modifying the receivers possessed by a majority of amateur radio operators. An article in the USSR publication Radio in June 1957 provided technical details about the motion of their planned satellite in its orbit, the propagation of its signal, and arrangements for receiving it. That article was largely unknown in the West until after the Sputnik 1 launch.16 After that occurred, a translation was provided to the International Geophysical Year (IGY) technical panel on ionospheric physics, and a condensed version of that translation appeared

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in QST in November 1957.17 The primary emphasis in that article was on the use of amateur radio observations for orbit determination—telemetry reception instructions were notably absent. For the next several months, QST carried a number of articles dealing in one way or another with Sputnik 1 signal reception.18

As another interesting historical note, during one of our telephone conversations on 27 November 1957, Van Allen mentioned his interest in adding a capability to transmit continuously from the U. S. satellites at a lower frequency to extend the coverage to a wider network of ground receiving sites, including radio amateurs.

The signals at the IGY-approved satellite-transmitting frequencies of 108.00 and 108.03 MHz would propagate only in straight lines. That band had been chosen for just that reason, so that the satellite orbital path could be measured to the desired precision. The straight-line propagation was not important for transmitting the telemetry data, however, and, in fact, limited the area over which reception would be possible. Van Allen knew from his personal experience in receiving the Sputnik 1 signal during his South Pacific expedition that transmission at a frequency of 20 MHz would expand coverage because the signal path would be bent by the ionosphere. He reasoned that it should be possible to meet more of the cosmic ray experiment’s wide-area coverage requirement if a 20 MHz transmitter were added. He stated that unspecialized receiving equipment should permit the reception of the 20 MHz signal for periods of about 25 minutes on each pass, and that it should be possible to receive sequences of at least five consecutive passes.19

The idea was alluring enough that he elevated that question two days later in a letter to the two working groups of the Technical Panel on the Earth Satellite Program (TPESP). That letter advocated continuous 20 MHz satellite data transmission at a level of about 0.1 watt. His letter expressed a set of personal observations, including his belief that a single well-located receiving station could provide telemetry recovery for about one-fourth of the time, that the change would lend itself to added telemetry recovery by radio amateurs and others, and that continuous transmission at that frequency might eliminate the need for onboard data storage in future missions in the interest of simplifying the onboard instruments.

His recommendation was seconded nine days later by Vern Suomi at the University of Wisconsin, who stated that such a transmitter would permit substantial simplifica­tion of the Vanguard instrument he was developing to measure the Earth’s radiation balance.20

Van also discussed this point with Pickering, who once informed me that his working group had discussed transmitting at the 20 MHz frequency from the Deal satellites at an earlier meeting of the TPESP but had decided against it “for political reasons.”

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Nevertheless, by the time of Van Allen’s letter, it was too late to make the change in any of the Deal satellites. His recommendation was implemented later in the Explorer 7 satellite, as related in Chapter 13. As the space program evolved after that, however, the demands for higher data rates from Earth orbit required the higher transmitting frequencies. The specially designed satellite receiving stations became an established feature of space operations, and the possibilities for radio amateur participation dimin­ished. To my knowledge, no other U. S. satellites were designed to transmit at 20 MHz, not even the Oscar satellites that were built by the amateur radio enthusiasts some years later.

Major problems in preparing the ground networks Preparing the network of Mini­track and Microlock stations for the Deal satellites was not without its share of prob­lems. Building the completely new Minitrack system by NRL was a major project in its own right and encountered the typical problems of such endeavors.

The Microlock effort at JPL encountered a major snag at the outset. The Department of Defense (DoD) was initially reluctant to provide the needed financial support. In fact, soon after approval of the Deal program, it issued a directive that limited the Microlock network to the station at Cape Canaveral, Florida (essential for launch support), and the engineering development station in Pasadena. Upon learning of that directive in the early afternoon of Wednesday, 27 November, I immediately called Van Allen. He was, at that moment, preparing for concurrent meetings of the IGY Rocket and Satellite Research Panel and its TPESP to be held on 6 December. He asked me to inform Pickering of that meeting and to tell him that Caltech’s Lee Dubridge would be attending it. He suggested that the two of them might be able to address the problem there.

Pickering immediately set up a conference call that included Henry Richter, Al Hibbs, C. I. Cummings, K. W. Linnes, and me.21 He informed us that, al­though IGY officials had not expressed any opposition to the addition of Microlock (even though it represented a major change in several years of Vanguard planning), they were not willing to openly contest the DoD directive. During that conversa­tion, we identified five possible options for providing the Microlock coverage that we felt we needed: (1) get the DoD position reversed in some way, (2) get ad­ditional coverage without major DoD financial support as a shoestring operation, (3) get the IGY program to help fund it, (4) get IGY participants in India or Japan to set up stations, or (5) see if the University of Iowa could help in some way.

Pickering also sent identical letters to Professor Masasi Miyadi at the Tokyo Astro­nomical Observatory and to A. P. Mitra, secretary of the Indian National Committee for IGY.22 Those letters outlined the need for global telemetry coverage and en­couraged them to construct stations suitable for recovering the Deal telemetry. The

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Japanese did follow through in time to provide valued support by establishing a station near Tokyo, as mentioned earlier.

The next morning, I informed Van Allen that Pickering would be in New York on 5 December to argue the Microlock issue.23 Van offered his help in presenting the scientific basis for increased Microlock coverage and prepared charts to help clarify the issue.

Ultimately, by a combination of continuing vigorous actions and some good luck, a robust network of Microlock ground stations was operational by the time of the Deal I launch.

A second major ground station crisis occurred relatively late in the game. Through a telephone conversation with Roger Easton at NRL on Wednesday, 19 February, just two weeks before the planned launch of Deal II (Explorer II), I learned that the interrogating transmitters were not ready at the NRL Minitrack ground stations, except for the station at Blossom Point, Maryland. The others lacked antenna-matching networks, and about half of them still needed work on the transmitter control panels. That threatened the success of our experiment, as without them we would have been unable to read the data from the onboard tape recorder for most of the orbits. I immediately called Van Allen, who, in turn, called Bill Pickering at JPL and John Hagen, the Vanguard project director at NRL.

Apparently, in the rush of switching our Iowa experiment from the Vanguard program to the Jupiter C program, although we thought the requirement for Vanguard command support was fully understood, no explicit written request for such support had been filed. That omission was immediately rectified by a letter from Pickering to Vanguard’s John Mengel. The text of that letter read:

This is to state that a requirement exists for the operation of interrogation transmitters for the University of Iowa satellite experiment. This payload contains a tape recorder used in connection with the ground interrogation system for the recording and transmission of the complete cosmic ray counts each orbit. It is essential that as many of the Minitrack fence stations as is possible be prepared to interrogate the satellite communications system. The time is very short in which this must be set up. For this reason, details will be worked out in a meeting between us on February 21. If a sufficient portion of the Minitrack system cannot be made available in time, our firing date will have to be delayed in order that a meaningful experiment will result.24

Henry Richter and I made a hasty departure for Washington on Thursday afternoon to be there for a meeting with John Mengel, Roger Easton, and Marty Votaw the next morning. Mengel’s and my independent reports summarized the results. Agreements were reached to retune the Minitrack receivers to the Deal II frequencies and to ready the Minitrack command transmitters for the mission. We received assurance that the Blossom Point, Maryland, station was in operation, and that the Fort Stewart, Georgia; Havana, Cuba; Antigua, British West Indies; Lima, Peru; Antofagasta, Chile; and San

CHAPTER 11 • OPERATIONS AND DATA HANDLING 305

Diego, California, stations would be ready in time. As parts for the Quito, Ecuador, station had been lost in transit, and the Santiago, Chile, station was dealing with various cable problems, their readiness was in some question.25 26

In reality, it took a heroic effort on the part of the Vanguard engineers and station personnel to complete the arrangements during the short time remaining. Installation and checkout of the command transmitters for the South American stations were performed by Fred Friel of NRL and C. Cunningham of the Lima Station, with Friel hand carrying the necessary parts and instructions. The full array of Minitrack interrogating stations was completed only about a week before the Deal II launch. That seemed then, and even more so now, a miracle. The NRL engineers and operators certainly extended themselves magnificently to achieve that goal.

That January meeting also provided an opportunity to address other details in preparation for the Deal II launch. They included backup procedures for pointing the antennas in case the satellite’s low-power transmitter should fail prematurely, procedures for recording and forwarding ancillary information about interrogation times and performance, and the handling of the ground-recorded telemetry tapes. Henry and I also made a brief stop at the IGY Office in downtown Washington, and we visited the Vanguard Computing Center at 615 Pennsylvania Avenue, Northwest to learn whether all necessary preparations had been made for orbit computation and initial data processing. Henry returned to Los Angeles that evening.

The next morning I had some slack time before leaving Washington for Florida. That gave me an opportunity for some Washington tourism, including walking down the stairs in the Washington Monument. That evening, I flew to Orlando and made my way to Cocoa Beach. On Monday, 24 February, I joined the JPL engineers at Cape Canaveral to help in preparing the satellite instruments for flight.

The United States and Soviet Union were in the midst of the 30-year cold war. By mid-1958, both possessed proven capabilities for producing nuclear weapons and for delivering them by one means or another to the other country. And both were near-paranoid in their suspicions of the other.

Thus, both were urgently examining potential capabilities for detecting the det­onation of nuclear test devices by the other country, and for protecting themselves against atomic bomb attacks if they should occur. In the United States, air filters to remove radioactive debris from the air and airborne water had been developed by the

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Naval Research Laboratory (NRL) as early as 1947.1 Beginning in late 1948, several weather reconnaissance B-29 squadrons routinely patrolled over the Pacific Ocean with those air filters to assist in detecting Soviet test detonations. The first Soviet nuclear detonation, referred to as Joe-1 in the United States and as RDS-1 in the USSR, and occurring on 29 August 1949, was first detected by ground and airborne air and rain filters of that type. The Weather B-29s that I was flying for weather reconnaissance over the Pacific Ocean during 1952 continued that nuclear detonation monitoring effort as an add-on classified mission objective.

Beginning as early as July 1957, our country relied heavily on the Distant Early Warning Line (DEW Line), a network that eventually grew to 63 radar and commu­nications stations built across northern Canada and Alaska to provide early detection of any Soviet aircraft or missiles that might be headed for the United States.

The Soviets announced their successful test of an Intercontinental Ballistic Missile (ICBM) on 26 August 1957. That demonstrated an improved capability for launching nuclear weapons against the United States.

With that new information, Nicholas C. Christofilos, a physicist working on magnetic fusion at the Lawrence Livermore National Laboratory (LLNL, operated by the University of California, Berkeley), became greatly concerned that the Soviets might try to conceal a sneak ICBM attack by detonating a nuclear device beforehand at high altitude. The ionospheric effects and the synchrotron radiation resulting from spiraling electrons produced by the blast might cause radio interference that would severely limit the range at which the DEW Line could see approaching missiles. Conceivably, that particle shell might completely blind the radars.

With the launch of Sputnik 1 on 4 October, Christofilos’ concern heightened. He believed that the new Soviet capability placed the United States in near-term peril. Building on his experience with magnetically confining charged particles, he came up with the idea of depositing and storing huge numbers of electrons in the Earth’s magnetosphere to make a defensive shield. The source of the electrons would be a large number of nuclear explosions at high altitude.

During October and November 1957, he discussed that possibility repeatedly with Herbert F. York, then director of the LLNL. According to York, Christofilos even predicted the existence of the naturally occurring trapped radiation before it was discovered by stating, during those discussions, that “there are already high energy (MeV range) electrons trapped there!” He believed that cosmic rays hit­ting the Earth’s atmosphere produced, among other things, neutrons; some of those moved radially outward and decayed, and a fraction of those were trapped in the magnetosphere.2

Christofilos thought that an electron shell, if produced by the United States, might serve as a defensive electromagnetic shield against Soviet ICBMs. If dense

CHAPTER 13 • ARGUS AND EXPLORERS IV AND V 361

enough, it might heat the outer surfaces of approaching ICBMs to make them bright enough targets for heat-seeking defensive missiles. Beyond that was the possibil­ity that a sufficiently dense shell (produced by perhaps thousands of megatons of nuclear detonations per year) might directly damage approaching missiles or their warheads. They might even prematurely and harmlessly trigger incoming nuclear bombs.

His concept became known as the Argus Effect, and the endeavor to test it became known as the Argus Project.

The government’s support of veterans’ education via the G. I. Bill following World War II forever changed the character of university education in the United States.1 It

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enabled thousands of veterans to go to school who would not otherwise have been able to do so. By 1947, veterans made up 49 percent of U. S. college enrollment. By the end of the bill’s coverage in 1956, 7.8 million veterans attended universities, colleges, trade schools, and business and agriculture training programs.

The bill brought to the campuses a whole generation of intensely focused students whose war experiences had given them a much different outlook than that of typical prewar students. Being older than most of the traditional students, many brought along wives and young children.

To accommodate returning married G. I.s and the other student families, many universities built small villages to house them. Eight such villages of three types were built at the University of Iowa. Representative of the first type was Hawkeye Trailer Village on Old Iowa Field on the east bank of the Iowa River (near where the University Library now stands). It contained 128 trailers, whose inhabitants shared communal showers and washhouses. Ernie and Mary Ray occupied one of those units for a while. The trailers, however, did not hold up well, and by the time we arrived in 1953, the university administration had decided to remove a trailer whenever it required repairs of $50 or more.

More substantial Quonset huts and corrugated sheet metal barracks in other villages were tremendously successful. The military surplus round-topped Quonset huts held up well and had more complete facilities, including in-house showers. Les and Marilyn Meredith lived in one of those in Riverside Park, located along North Riverside Drive near the present Art Building.

Rosalie and I considered ourselves fortunate to live in one of the slightly larger half-barracks, located just west of the original University Hospital building in what was known as Finkbine Park. Templin Park, the last of those temporary villages, was razed in 1975 in favor of more permanent brick-and-mortar housing units, as the ancient custom of marriage only after college was largely outmoded by then. The site of Finkbine Park is no longer recognizable, being now a part of the university’s huge medical and sports complex.

The University of Iowa counted a total enrollment of fewer than 10,000 students in 1953 when I started, and passed that mark while I was there. By 2008, the enrollment has surpassed 30,000. When I was there, class sizes were small by today’s standards—I can recall no class larger than 200, and classes that large were rare. Classes for physics and engineering majors ranged from a few to no more than 25. One-on-one sessions with faculty members outside the classroom on short notice were nearly always possible.

Compared with the more traditional single students of the prewar era, the older married students had less time and energy for social and other nonacademic campus activities. Their families, with the need for paying employment to help support them, lent a

CHAPTER 16 • SOME PERSONAL REFLECTIONS 433

new focus and sense of urgency to the university experience. Although fraternity and sorority life was still present, it was not a part of the university experience for most of the married students.

To highlight the difference, my father, while a bachelor in his senior year in 1921 at Western Union College in LeMars, Iowa, participated actively in the Decameronian Literary Society (vice president, debates, orations, lectures, and plays), Science Sem­inar, band, glee club, Young Men’s Christian Association, and the Cleric organization. He considered those activities to be important elements of his classical liberal arts education.

There were times when I regretted not having had more time for that type of extracurricular activity, but the responsibilities of a growing family, the need to work to supplement my G. I. Bill income, and my different interests at that stage in life took precedence. Still, I never felt cheated. The undergraduate curriculum in physics at Iowa embodied a well-balanced mix of the technical, historical, and philosophical aspects of physics, along with exposure to world history, ancient and modern literature, English language structure and composition, the German language, mathematics, and the creative arts. The only area in which I regretted the lack of more training and experience was in oration, including open debate on nontechnical subjects. Nevertheless, I emerged from my undergraduate years with an excellent classical liberal arts education. [11]

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Study Program. That seemed to offer experience with a company that might help me decide upon a specific direction for my postgraduate work. As an added fac­tor, both Rosalie and I wished to live closer to her family on the West Coast for a while.

That inquiry led to a letter of acceptance by Lockheed, with the understanding that I would work at their installation in Palo Alto—full time during school vacations and about half time during school semesters. The two year appointment would include salaried work in their facilities, and they would pay my tuition and other expenses at any suitably accredited university. My hope was that I would attend Stanford University, but I learned that the deadline had already passed for application to their very limited Industrial Students Program. That meant that I would have had to travel between Palo Alto and the University of California in Berkeley. The thought of commuting a distance of 35 miles each way through heavy San Francisco Bay traffic completely repelled me. It would have made it impossible for me to have the type of strong campus interaction that I enjoyed at Iowa.

In mid-April, I rather reluctantly rejected their offer. The basic idea remained alive, however, until late summer. During a vacation trip to visit Rosalie’s family in the Seattle area in early September, I described the work I was doing to a physics faculty member on the University of Washington campus. At the end of my summary, he asked, “Why would you want to go anywhere else than Iowa?”

That clinched it—I dropped any further thought of leaving the University of Iowa. Needless to say, I have been eternally grateful that I stayed.

I was born in Sharon Center, Iowa, a tiny crossroads cluster 10 miles southwest of Iowa City. My life until the time of high school graduation was centered on the small Ludwig farm near Tiffin. At about age 11, flying and electronics began to consume much of my free time. During my high school years, many of the Tiffin residents came to depend upon me for repairing their ailing radios and household appliances.

Immediately upon graduating from our small high school in 1946, I volunteered for service as a private in the U. S. Air Force. Serving for a year as an enlisted man, then for a year learning to fly in aviation cadet school, I received my wings and second lieutenant bars in July 1948. During four and half more years as a multiengine pilot, a squadron electronics officer, and other assignments, I was exposed to an ever-broadening range of experiences and satisfied my lust for travel.

Rosalie F. Vickers traveled with her family from Tacoma, Washington, to Biloxi, Mississippi, to marry me in July 1950. At that time I was attending radar school. Dur­ing the next two-plus years we enjoyed a nomadic military life at posts in New Mexico, Idaho, and California. Our first daughter, Barbara Rose, was born in February 1952.

I had always strongly believed that I needed a university education. Several efforts to pursue that goal as an air force officer proved fruitless, so I felt compelled to leave the active military service. On 18 December 1952, Rosalie, our 10-month-old daughter, and I departed from my final duty station in Sacramento, California, with only a very general concept of what the future might hold. When we arrived back at my boyhood home in Iowa, I had no income-producing job and very little money. Our second child was on her way. Van Allen’s offer of a position in the Cosmic Ray Laboratory was a godsend.

This book chronicles my university years, progressing through our family’s arrival in Tiffin in mid-December 1952, the birth of our daughter Sharon Lee in 1953, the receipt of my B. A. degree in February 1956, the birth of our son George Vickers in 1958, the receipt of my M. S. degree in February 1959, the birth of our fourth child, Kathy Ann, in August 1960, and ending with receipt of my Ph. D. degree a few weeks later.

Along the way, I helped in designing and building eight of the earliest U. S. Earth satellite instruments and in the use of the four of them that reached orbit.

As my final graduation approached, I accepted a position with the then-forming Goddard Space Flight Center (GSFC). Moving with my family to Silver Spring, Maryland, in Septem­ber, I formed and directed an instrument development section in Frank McDonald’s Fields and Particles Branch. From then until 1965 my work included development of a progression of satellite and space probe instruments, service as project scientist for a series of Orbit­ing Geophysical Observatories, and participation in the rapidly evolving scientific research program.

Subsequent positions included director of the Information Processing Division at Goddard and a move to the National Oceanic and Atmospheric Administration (NOAA) in 1972 to set up and direct an Office of Systems Integration in the National Environmental Satellite Service. My work in NOAA included establishment of the Geostationary Operational Environmental Satellite system and the TIROS-N polar orbiting system and, subsequently, direction of the operation of the two systems.

In 1980, Rosalie and I moved to Boulder, Colorado, andNOAA’s Environmental Research Laboratories (ERL). After a period as the ERL director, I returned for a short term at the

CHAPTER 2 • THE EARLY YEARS

headquarters of the National Aeronautics and Space Administration (NASA), where I retired from government service in 1984.

Various consulting roles, work as a research associate at the University of Colorado’s Laboratory for Atmospheric and Space Physics, and an assignment as a California Institute of Technology Visiting Senior Scientist at NASA Headquarters occupied my attention for the next seven years. In 1991, I retired from all further work in the space arena, and Ros and I made our retirement home near Winchester, Virginia.

My work in the Cosmic Ray Laboratory evolved rapidly over the three years of my undergraduate schooling. My earliest work included general laboratory work on a variety of test instruments. The first substantial task of note was to design and build a new type of marker pulse generator. At the same time, I helped Joseph (Joe) E. Kasper in building the differential analyzer (an early analog computer) that was the basis for his master’s degree.1 As time progressed, in addition to instrument development and construction, I oversaw more and more of the daily operation of the laboratory, including organizing and ordering supplies and supervising some of the student aides.

And I quickly edged into the fine art of building balloon and rockoon instruments. Figure 2.1 shows me with some of my early work.

The SUI rockoon program culminated in a pair of field exercises that were supported as a part of the IGY endeavor. The ambitious expeditions were undertaken in the fall of 1957 by James Van Allen, Larry Cahill, and their coworkers.

Cahill’s rockoon magnetometer While still at the Applied Physics Laboratory, Van Allen had been aware of an invention by M. Packard and R. Varian, a proton free-precession magnetometer.21 That instrument was intrinsically capable of making very precise measurements of the magnitude of a magnetic field—its precision was believed to be sufficient to make a clear distinction between the Earth’s strong main magnetic field and very weak magnetic fields hypothesized to result from electrical currents in the ionosphere. Members of Van Allen’s group at the Applied Physics Laboratory and researchers at the Naval Ordnance Laboratory conducted several searches for those ionospheric currents during the very late 1940s and the opening of the 1950s by the use of flux-gate magnetometers.22 The possibility of using the more precise proton free-precession magnetometer for that purpose, although attractive, was not pursued then.

The idea resurfaced in early 1954, when Van Allen suggested to the Upper Atmo­sphere Rocket Research Panel that the free-precession magnetometer might be used in the search for the ionospheric currents.23 At his fall 1954 meeting with his graduate students at Iowa, Van Allen outlined that basic idea and suggested that such a project might be undertaken by one of them by developing a miniaturized version that would fit within the physical envelope of a Loki rocket. If that could be done, the instrument could be carried at low cost to a sufficient height to detect the currents.

CHAPTER 4 • THE IGY PROGRAM AT IOWA

Larry Cahill, as mentioned earlier in connection with the 13 March 1956 balloon flight of his magnetometer, had joined the Iowa research group in 1954 and agreed to take on the challenging new developmental project.

Three paths were initially advanced for reaching the U. S. goal of launching a satellite. Those were (1) a relatively heavy payload to be launched with the air force’s Atlas Intercontinental Ballistic Missile, (2) an extension of the army’s Jupiter Intermediate – Range Interballistic Missile (IRBM) development program by Wernher von Braun’s group at Huntsville, Alabama (Orbiter), and (3) a launch vehicle based on the navy – managed Viking and Aerobee-Hi sounding rockets (Vanguard).

Atlas With its origin in the early 1950s, and with the initiation of its all-out high-priority development in May 1954 following the first U. S. fusion nuclear bomb

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tests, the Atlas was being developed as the first U. S. Intercontinental Ballistic Missile (ICBM).

In 1955, when the satellite launch vehicle debate was unfolding, the air force put forth a proposal for a 150-pound satellite to be launched by the Atlas rocket. They considered that weight to be the minimum payload required to perform the exper­iments that they envisioned. They emphasized that the Atlas would ultimately be capable of placing hundreds, or even thousands, of pounds into orbit. Furthermore, it would use proven components, use only two stages, subject the payloads to rela­tively low acceleration forces, and offer the advantage over the other two proposals of simplicity of design. They acknowledged clearly, however, that it would not be pos­sible for them to launch even a minimal satellite without interfering with the ICBM development, because of competition for facilities, propulsion sources, and skilled personnel.

An additional negative factor was that the first test flight of the Atlas was not due until well into the IGY period, and its availability in time for a satellite launch before the end of the IGY was questionable. There was also concern that use of the country’s primary ICBM missile for the IGY satellite might confuse the desired distinction between the country’s military programs and the nonmilitary IGY research endeavor.1

The Atlas made its first (unsuccessful) test flight on 11 June 1957, and partly successful test launches were achieved by September 1958. The first completely successful launch, with a realistic payload and traveling the planned distance, took place on 28 November, over a year after the Sputnik 1 launch. Three weeks later, on 18 December 1958, an Atlas B was placed in Earth orbit as Project SCORE. That “Christmas Satellite” caused a major sensation by broadcasting a prerecorded Christmas message from President Eisenhower.

The Atlas eventually became a true workhorse of the spacecraft-launching stable, first for air force military and intelligence missions, and then for National Aeronautics and Space Administration (NASA) space exploration missions.

It is a fascinating note of history that each of the first two space-faring countries used the launch of a payload into Earth orbit as the first public demonstration of the prowess of their ICBMs. The Soviet Sputnik 1 launch occurred only six weeks after the first fully successful R-7 ICBM test launch, and the Atlas SCORE launch occurred only three weeks after the first successful Atlas ICBM launch.

Since the Soviet Sputnik launch was achieved about 14 months before the U. S. SCORE launch, it led to a public perception that the USSR was ahead, not only in missilery, but by extension, in the whole broad arena of technology. That proved to be not true, as even at that time, the United States had a strong lead in missile guidance and general electronics technologies. Overtime, the advantage of the initially superior Soviet lifting capability was overcome by the U. S. lead in other high technologies. It

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resulted, in a little over a decade, in the United States placing humans on the Moon’s surface, while the Soviets had to abandon their efforts to do so.

Hermes, Redstone, Orbiter, and Jupiter C Wernher von Braun’s team moved from Fort Bliss, Texas, to the Redstone Arsenal in Huntsville, Alabama, in 1950. That group formed the Guided Missile Development Division in the army’s Department of Ordnance. It was reorganized as the Army Ballistic Missile Agency (ABMA) in February 1956 following the Department of Defense approval of their Jupiter program.

The group’s first task at Huntsville was to develop the Hermes rocket. Over time, that rocket evolved into the Redstone IRBM. Both were easily recognized descendents of the German V-2 rocket, which had demonstrated its technical soundness and utility through over 60 firings in Texas, plus two flights with Women’s Army Corps (WAC) second stages (called Bumper rockets) from Cape Canaveral, and one flight from the deck of the aircraft carrier USS Midway.

Although the exact date of origin of the Redstone project is indistinct, the Redstone name was attached on 8 April 1952. The Redstone missile made its first test flight in August 1953 and its first successful full-range flight in January 1954.2 By the time of the president’s announcement in July 1955 of the U. S. intent to mount a satellite effort, eight Redstone test launches had been made with varying degrees of success. By the time of the Sputnik launch in October 1957, 19 additional test firings had occurred, and all but 4 of those performed successfully. By then, the missile was approaching operational deployment status. That deployment was made to Europe in June 1958.

Von Braun’s eyes had been set toward space since his early rocket flights in Ger­many during the 1920s and 1930s, and even during the wartime V-2 development at Peenemtinde. After he and his team came to the United States following World War II (WWII), and while their primary work under army auspices was being directed toward the development of short – and intermediate-range military rockets, he and his associates continued to dream of rocketing into space.3 4

Thus, from early in the Redstone development at Huntsville, von Braun was think­ing of using it to launch a satellite. Ernst Stuhlinger, his senior scientist, recalled, “Sometime in 1952, von Braun remarked to me: ‘With the Redstone, we could do it.’—‘Do what?’ was my answer. ‘Launch a satellite, of course!’ And then, he de­scribed how three small stages of solid propellant rockets on top of a Redstone, ignited when the rocket had reached its apex point, could put a small satellite into orbit.”5

While that idea languished for some time within all governmental circles, enthu­siasm for space flight was growing in other arenas. For several years beginning in about 1952, the American Rocket Society (ARS) and the British Interplanetary So­ciety featured articles on possible launching rockets, satellites, and the mechanics of interplanetary flight.

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It was in late 1953 that several far-thinking individuals became increasingly con­vinced that the time had come for more concrete action. In June 1954, Commander George W. Hoover at the Office of Naval Research and Frederick C. Durant III, pres­ident of the International Astronautical Federation, convened a meeting in the navy’s old temporary wooden building T-3 on Constitution Avenue. That meeting included von Braun, Ernst Stuhlinger, Gerhard Heller, Rudolf Schlidt, and several others from Huntsville; as well as Fred L. Whipple (chairman of the Department of Astronomy at Harvard University); S. Fred Singer (physicist at the University of Maryland); David Young (Aerojet General Corporation); and Alexander Satin (chief engineer in the Air Branch of the Office of Naval Research). Hoover opened the meeting with the words, “Gentlemen, the time has come to stop talking and start doing. We will now go ahead and build a satellite.”6

Von Braun proposed using the Redstone rocket and a three-stage Loki cluster as the satellite launcher. The Loki was a simple antiaircraft rocket being routinely produced by the Aerophysics Corporation. The launcher’s second stage would consist of 24 Lokis, the third stage would use 6, and the final stage would consist of a single Loki with a five pound satellite payload. His concept was immediately embraced by the meeting attendees.

Fred Singer and some of his colleagues in Britain had suggested, as early as 1952, a 100 pound scientific satellite, which he called the Minimum Orbiting Unmanned Satellite of the Earth (MOUSE). At the 1954 meeting, it was clear that that large a satellite could not be lofted with currently available technology. Nevertheless, Singer was enthusiastic about the proposed five pound satellite program as a first step.

The overall concept that emerged from that meeting was code-named Project Slug to help keep it out of sight of the many who were heavily involved in military politics. The idea was presented to the Chief of Naval Research soon after the meeting. After study there by Milton W. Rosen and John W. Townsend Jr., he gave official approval for further investigation and authorized conversations between the navy and von Braun’s group at Huntsville.

On 3 August 1954, the navy representatives went to Huntsville for a meeting with then-colonel Toftoy and von Braun to discuss further details. Following that meeting, Toftoy went to Washington for a discussion with Major General Leslie Simon, the assistant chief of Army Ordnance. Simon stated that he would work with the navy on this project provided it would not slow the army’s missile weapons programs. The chief of naval research followed that by giving the Office of Naval Research’s Air Branch authority to proceed with preliminary studies. During those interactions, the name “Project Orbiter” emerged, and Commander Hoover became its project officer.

It was agreed that the army group at Huntsville would be responsible for the complete launching vehicle, while the navy would design the satellite and provide

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the Naval Research Laboratory’s (NRL’s) Minitrack system, other ground tracking facilities, and logistics support and would acquire the data. It was expected that they would be ready for a launch in 1956 from an island near the equator.

In September 1954, von Braun and some of his coworkers prepared a paper, “A Minimum Satellite Vehicle Based on Components Available From Missile Develop­ment of the Army Ordnance Corps.” The paper, submitted to army authorities as a classified document, provided many details of the design, performance, and operation of the suggested system. The paper asserted that a five pound satellite could be built with components available from their weapon developments. He suggested that a joint army-navy-air force “Minimum Satellite Vehicle Project” be established.

It was some time later that the Huntsville engineers suggested that the Redstone rocket might be upgraded by lengthening its tanks and substituting hydyne for alcohol as the fuel. With those changes, they believed that a satellite weight of 15 pounds could be orbited.

The efforts to sell the Orbiter concept continued on other fronts. On 24 November 1954, the ARS Space Flight Committee that was mentioned earlier submitted an open proposal based on the Orbiter concept. Titled “On the Utility of an Unmanned Earth Satellite,” it was submitted to the U. S. National Science Foundation (NSF). The proposal stressed the use of such a satellite in studies of astronomy, astrophysics, biology, communications, geodesy, and geophysics. Although the NSF did not act on the proposal, being preoccupied with other planning for the upcoming IGY, the ARS continued to promote the idea using its own resources.

William Pickering and his staff at the Jet Propulsion Laboratory (JPL) were brought into the Orbiter planning as a full partner after the ABMA and NRL sent their proposal to Pickering for JPL’s review in late 1954.

The evolving proposal was submitted to Assistant Secretary of Defense Donald A. Quarles, in charge of army research and development, on 20 January 1955. Recog­nizing the growing interest in launching satellites within all three of the U. S. military services, and of growing indications of a similar interest in the Soviet Union, Quarles, instead of acting on the proposal, established a new Ad Hoc Committee on Special Capabilities chaired by Homer J. C. Stewart. The committee came to be known as the Stewart Committee. Its task was to recommend which of the competing U. S. proposals ought to be supported.

An important decision was quietly made internally by the U. S. National Committee for the IGY on 14 March 1955 that the United States should initiate a satellite program. However, no public announcement of that decision was made, and it was only later that the Orbiter proponents learned of that decision.

Even as the Stewart Committee was being formed, planning for Project Orbiter continued. One feature of the Redstone-based launch vehicle was that it could be

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launched from a fully mobile launch platform that could be set up in short order at any location. In April, the Office of Naval Research began planning for a launch site survey in the Gilbert Islands in the Western Pacific. They planned that the survey expedition would depart in the spring of 1957, and that the actual Orbiter launch could take place in midsummer or the fall of that year.

Orbiter came to an abrupt end as an officially sanctioned project in September 1955, when the Stewart Committee made its recommendation and the Army Policy Committee and Quarles made the decision to proceed with the Vanguard launcher.

The Redstone rocket had a range of several hundred miles. The army needed a longer – range missile, and the Huntsville group proposed a 1500 mile IRBM in July 1955. Planning progressed throughout the rest of 1955, culminating in full approval of the program in December of that year and its official designation as the Jupiter program in April 1956.7

The first two phases of the Jupiter flight-testing program employed Redstone – based configurations to make early tests of certain critical new Jupiter technologies and components. Although built upon the Redstone rocket, they were considered part of the Jupiter development program and carried the Jupiter designation. Among other reasons, that kept them high on the priority list for procurements, and for testing at Cape Canaveral.

The first of those test configurations was called the Jupiter A. It made its first preliminary firing in September 1955 and its first fully successful flight to test the Jupiter inertial guidance system six weeks later. Over the Jupiter A lifetime, ending in June 1958, 25 vehicles were fired to test various components of the Jupiter IRBM. Twenty of those were mission successes, two were rated as partial successes, and only three failed.

Among other things, it was proposed that the Jupiter missile program use a new concept for dissipating the heat generated as the nose cone carrying the warhead reentered the atmosphere. The air force had adopted a heatsink approach for its ICBM. That depended on the absorption of the heat of reentry by a large mass of metal on the nose cone’s leading surface. The army team recognized that use of a high-temperature insulating ceramic on the nose cone offered the possibility of achieving the same result more economically. Ablation—conversion of the solid material directly into vapor as it heated—would carry away the reentry heat with a much smaller weight penalty.

The ablation approach represented completely new territory. Rather than incurring the delay, expense, and uncertainty of waiting to test that new concept by live firings of the full Jupiter missile after it became flight worthy, a new Redstone-based configura­tion was devised to provide a much earlier and lower-cost test, using readily available components. That second Jupiter test configuration, introduced into the program in

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mid-1955, was known as Jupiter C—standing for Jupiter-Composite. It was often referred to as the Reentry Test Vehicle (RTV). Permission and funds were obtained to build a dozen Jupiter C vehicles for that purpose

Not surprisingly, the RTV looked like an incarnation of the Orbiter launcher! It consisted of the Redstone first stage, plus two of the three upper Orbiter stages. The originally proposed Loki rockets were replaced in August-September 1955 by a smaller number of somewhat larger rockets, following a suggestion by Homer Stewart at JPL. The so-called scaled-Sergeant rockets were an outgrowth of JPL’s contract with the army to develop the Sergeant IRBM. The reduced size test rocket was built so that early developmental tests could be made on candidate formulations for the Sergeant rocket fuel. They were six inches in diameter, and 11 of those small rockets formed the Jupiter C second stage, while three made up its third stage.

The RTV (Jupiter C) configuration, though inelegant, was remarkably simple and robust. Three firings were made as a part of the Jupiter nose cone-testing program. The first, to demonstrate the soundness of the multiple-stage design, took place on 20 September 1956, over a year before Sputnik 1 was launched by the Soviets. For that launch, Von Braun was explicitly directed not to include an active fourth stage, to ensure that it would not “end up in space” and preempt the Vanguard program. In fact, the Pentagon brass, being fully aware of the great passion of the Huntsville group for space flight, sent a monitor to Cape Canaveral for the express purpose of ensuring that a live fourth stage was not “accidentally” mounted on top of the assembly. The payload for that first test consisted primarily of sand to simulate the weight of a scaled Jupiter nose cone. That test was fully successful, with the inert payload achieving a maximum velocity of about 12,000 miles per hour, a height of 682 miles, and a range of 3400 miles.

It was clear to all involved that a live final stage could have achieved orbit.

Two more flights of the Jupiter C carried scaled nose cones as their payloads. One on May 1957 was a partial flight success, with the missile taking an erratic course because of a guidance system malfunction. The nose cone from that flight lit at sea too far from the planned impact area to be recovered. A brilliantly successful third flight took place on 8 August 1957, with the nose cone being recovered and publicly displayed by President Eisenhower.

The success of that flight demonstrated the validity of the ablation-type nose cone design, and the nose cone-testing program ended. Nine remaining sets of Jupiter C hardware were in various stages of construction but no longer needed for their original purpose. Some of them were carefully stored “for any possible future use” (i. e., for launching satellites).

Aerobee, Aerobee-Hi, Viking, and Vanguard As the V-2 program in Texas was winding down in the late 1940s, the two stage Aerobee rocket was developed to provide

OPENING SPACE RESEARCH

a vehicle for continuing the country’s upper atmosphere scientific research program. It was developed by the Aerojet General Corporation and Douglas Aircraft Company under contracts from the Navy Office of Research and Inventions (predecessor to the NRL). Funding was provided by the U. S. Navy Bureau of Ordnance.

James A. Van Allen, at the Johns Hopkins University’s Applied Physics Labo­ratory, was a major instigator and overseer for the Aerobee program. He provided technical oversight throughout its development and early use, and prepared some of the instruments for Aerobee flights until he left Johns Hopkins in late 1950.

The completely assembled Aerobee, with its booster, main rocket, and nose cone, measured a little over 26 feet in length and 15 inches in diameter, with a gross weight at launching of 1068 pounds.8 Unguided, it was capable of carrying 150 pounds of payload instruments in a nose cone about 88 inches long by 15 inches in diameter at its base. During launch, the solid stage booster carried the rocket to a height of about 1000 feet, where the liquid-fueled main engine ignited. The 45-second thrust of that main engine, followed by its coasting after burnout, carried the rocket to its peak height.

The Aerobee enjoyed a remarkable record of performance in the U. S. suborbital high-altitude research program.9 Its first static test firing occurred on 25 September 1947, quickly followed by the first successful launch of an instrumented payload on 24 November. Most of the early Aerobees were launched from the army’s White Sands and nearby Holloman Air Force Base range facilities near El Paso, Texas. Five flights were made from two cruises of the USS Norton Sound. By the time of the Stewart Committee decision on the satellite launcher in August 1955, 55 Aerobees had been launched.

The Aerobee continued for a long time as a true workhorse—as of 17 January 1985, 1037 had been fired for a wide variety of investigations in atmospheric physics, cosmic rays, geomagnetism, astronomy, and other fields.10 The majority of the successful research flights achieved peak altitudes of from 40 to 65 miles, depending on payload weight and other factors. A record height of over 91 miles was achieved by U. S. Air Force flight 56 on 15 June 1955.

In response to a continuing need for even higher performance, an extension of the Aerobee rocket was developed, again, expressly as a carrier for upper atmospheric scientific research. Design and development began in 1952, when the navy and air force began working together with the Aerojet General Corporation. The resulting rocket retained the basic two-stage Aerobee design, but improved on the thrust-to – mass ratio of the main stage, increased the efficiency of the thrust chamber, and added more propellant.11

It was built in two versions, both designated Aerobee-Hi. The air force version, sometimes called the Air Force-Hi, was contracted in 1952, under direction of the Air

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Force Cambridge Research Center and the Wright Air Development Center. The navy version, likewise occasionally referred to as the Navy-Hi, was contracted in 1953, with direction from John W. Townsend Jr. of the NRL. The two versions were much the same, but the navy version contained more propellant. The air force version could carry a payload of 120 pounds to 160 miles, or 150 pounds to 145 miles. The navy version could carry 120 pounds to 180 miles, or 150 pounds to 170 miles.

The overall length of the navy Aerobee-Hi rocket, including both stages and the nose cone, was about 31 feet, and it had a diameter of 15 inches. The payload configuration was similar to that of the Aerobee—an approximately 88 inch long nose cone could accommodate up to 150 pounds. As with the Aerobee, there was no active guidance—a slow roll provided lateral stability.

At the time of the Stewart Committee’s Vanguard decision in August 1955, the Aerobee-Hi was just coming on line. The air force had test-fired two of its versions, and the navy made its first flight on 25 August.

The Aerobee-Hi rocket, too, had a distinguished record. By mid-1957, six air force launches had been made (including four test flights), and four flights achieved heights of over 100 miles. By the same time, the navy had launched 13 of theirs (including four test flights), and 7 of them reached heights of over 100 miles.

A rocket considerably larger than the Aerobee was developed for further expansion of upper atmospheric research. The NRL, under Milton Rosen’s leadership, contracted production of the rocket with the Glen L. Martin Company. The rocket was originally dubbed the Neptune, but that name was changed to Viking to avoid confusion because the navy was developing an aircraft named Neptune.12

Twelve Viking firings were made by the time of the Stewart Committee’s decision in 1955. Its record of success was outstanding throughout. There were no rocket-only developmental flights—all 12 carried instruments for upper atmospheric research. The first, launched in May 1949, achieved a height of 50 miles. Number 8 failed during a static firing. All others reached altitudes of from 31 to over 150 miles. Number 4 was fired from the afterdeck of the USS Norton Sound in May 1950 to a height of 104 miles. The others were launched from the White Sands Proving Ground in Texas.

The various launches included instruments for upper air pressure, temperature, density, winds, ionization, and composition; Earth photography; and solar and cosmic radiation studies. Especially notable firsts included the measurements of positive ion composition at an altitude of 136 miles on Viking number 10 in May 1954, and cosmic ray measurements at an altitude of 158 miles on Viking number 11, also in May 1954.

The Viking was believed at the time to be the most efficient rocket in existence. However, because of its high replication cost of about $450,000, it never became a pervasive feature of sounding rocket research. By the time of the satellite launcher

OPENING SPACE RESEARCH

deliberations, two more Vikings remained on hand out of the original purchase and were offered for use in the Vanguard program.13

In 1954, when the possibility of launching an Earth satellite was growing in the United States, and especially after President Eisenhower announced his decision to launch one in 1955, the suggestion was advanced by a group at the NRL under John P. Hagen’s leadership that a combination of the navy-developed sounding rockets be used to launch it.

That concept, named Vanguard, would employ an improved version of the Viking rocket as a first stage, a modification of the main stage of the Aerobee-Hi as a second stage, and a solid propellant rocket as a third stage. As stated above, the Viking had already achieved an enviable record of success, the Aerobee was in regular service, and the Aerobee-Hi was successfully entering service. The development of a suitable third stage was believed to be a simple extension of the currently available technology.14

The fully assembled Vanguard launch vehicle was to be 72 feet long and 45 inches in diameter at its thickest point, with an all-up weight of 22,000 pounds. The first stage Viking would burn a mixture of alcohol and gasoline, with liquid oxygen as the oxidizer. Its thrust was to be 27,000 pounds during a burn of 140 seconds. Its motor was mounted in gimbals and steered to maintain the desired flight path.

The second-stage Aerobee-Hi derivative was to be powered by nitric acid and hydrazine. Its motor was also gimbaled for steering. Auxiliary jets provided stabiliza­tion during the coasting phase and spun it on its long axis just before final third-stage ignition. The second stage contained the control system for all three stages.

The second-stage nose cone contained the third-stage solid fueled rocket and its satellite payload. The third-stage rocket was unguided, but the spin imparted by the second stage averaged out variations in the thrust of its motor to keep it on a straight course.

The written Vanguard proposal included extensive content related to the devel­opment and building of the research instruments. That benefited greatly from the experience at NRL in building and flying scientific instruments in its sounding rocket programs. It was also proposed that a navy-developed system would be used for satel­lite tracking and data transmission. That would be a derivative of an instrument devel­opment in the Viking program—the Single-Axis Phase-Comparison Angle-Tracking Unit, later known as Minitrack.