The launch countdown was in its final few minutes, and the cylindrical “tub” atop the first stage of a Juno I launch vehicle was spinning rapidly. Finally, a voice over the intercom intoned, “four – three – two – one – ignition – liftoff.” My senses were soon overwhelmed by the thunder of the rocket engine, as it beat upon me to affirm ignition and the beginning of the rocket’s purposeful climb toward space.
At the very tip of that multistage rocket assembly was a payload containing a cosmic ray instrument that I had painstakingly designed over the past two years as a graduate
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student at the University of Iowa.2 Perched on a stool in a nearby hangar, I listened with growing satisfaction to a wavering tone from a receiver on the workbench before me. During the 10 minutes following liftoff, the signal told me that the counting rate of the instrument’s Geiger-Muller detector increased, peaked, and then dropped slightly to an essentially constant value.
That counter was detecting showers of secondary atomic particles produced by collisions of high-energy galactic cosmic rays with molecules in the Earth’s upper atmosphere. Its counting rate increased as the instrument rose to a height of about 60,000 feet (11 miles or 18 kilometers),3 where the production of secondary particles peaked. As the counter progressed higher above the substantial atmosphere, it detected fewer and fewer of those secondary particles until, ultimately, the counter registered little other than externally arriving primary cosmic rays.4 5
Thus, the signal’s pattern told me that the rocket had successfully climbed to a height of at least 11 miles, passed above it, and remained above that height until it passed out of range. Furthermore, it showed that the instrument and transmitters in the payload were operating properly.
Down-range tracking stations quickly confirmed that the four-stage rocket had completed its work in lifting the 18 pound payload with my precious instrument package to the intended height of about 220 miles and in propelling it to the required speed of slightly more than 18,000 miles per hour. Although those down-range stations were able to measure the approximate speed of the departing final rocket stage and instrument, they were not capable of accurately determining its exact direction of flight. Thus, it remained possible that it had been aimed excessively upward or downward, in which case it would make a premature fiery descent into the atmosphere. Although preliminary indications of a successful launch looked promising, we still did not know whether the instrument was in a durable orbit.
By that time, there was nothing more that I could learn in the hangar, and I quickly made my way to the project’s more complete receiving station. Located in a special trailer some distance from the other Cape facilities, this was one of a global network of stations setup to receive the signals from the U. S. satellites. That station was especially important at that moment because it was linked to the rest of the receiving station network by high-quality telephone lines. That communication network permitted us to hear of the progress in acquiring the signal as the instrument progressed above other stations around the world. I joined a steadily growing and increasingly excited group at the trailer’s steps.
We did not expect to hear a meaningful confirmation that the instrument had been successfully orbited until it had made a nearly complete circle of the Earth, when it would come within range of receiving stations on the west coast of the North American continent. Expectations were that it would pass within range of four stations in California between 12:25 and 12:30 EST.
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The time of anticipated signal acquisition came with great excitement but passed with the disappointing absence of any signal. During the next minutes, we waited with a growing dread that the launch or instrument might have failed. Just as my fear was peaking, at about 12:42 EST, a voice from the trailer shouted, “Gold [the Earthquake Valley receiving station] has it!” We knew then that the rocket had provided a greater thrust than expected, resulting in a higher orbit. Thus, it took longer than expected for the new satellite to orbit the Earth. Our knot of observers exploded with applause and shouts of relief and jubilation as we realized that
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Joy also reigned in Washington, D. C. The three primary leaders of the effort, Wernher von Braun, directing the booster rocket effort, William H. Pickering, leading the upper-stage rocket and overall satellite effort, and James A. Van Allen, the principal scientist for our cosmic ray experiment, along with a bevy of Army generals, followed the launch and the interminable wait in a “war room” in the Pentagon. As soon as the orbit had been confirmed, the three were whisked to the National Academy of Sciences building on Constitution Avenue. There they briefed several civilian program officials and then led a spirited press conference in the academy’s Great Hall.
Word of the accomplishment immediately spread worldwide, as the front pages of the morning papers were emblazoned with the welcome news.
That event signaled both a conclusion and a beginning. On the national scale, it represented the culmination of a major effort to orbit the first U. S. artificial earth satellite. In Iowa City, it marked the realization of James A. Van Allen’s long-standing dream of placing cosmic ray instruments well above the Earth’s atmosphere. On a personal note, it was the end of a busy and exciting two year developmental effort that later served as the basis for my physics master’s thesis.
The event initiated a new era of scientific research within the Earth’s magnetic shell and beyond. The ensuing half-century of remarkably active and productive research in space has included the conduct of countless scientific investigations throughout our solar system, the announcement of numerous important scientific discoveries, and the training of many scientists who became leaders in the new field.
How did we get to this point, and what followed the initial excursion into space?
Endnotes
1 The corresponding universal time (UT, also commonly referred to as Greenwich Mean Time (GMT)) was 03:47 on 1 February 1958. Local times are used throughout most of this
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book. However, in discussions of the worldwide network of ground receiving stations and the data produced by them, the author reverts to universal time to avoid confusion. Such occurrences are appropriately identified.
2 During the period covered in this work, the university was known as the State University of Iowa (SUI), sometimes rather derisively pronounced “soo-eee.” Several decades ago it came to be known, simply, as the University of Iowa (UI). The two names are used here synonymously, with SUI being preferred when describing the events of the 1950s.
3 U. S. units of measure are used throughout most of this book, occasionally with corresponding international (SI) units indicated in parentheses.
4 An excellent summary of the state of knowledge of cosmic ray physics at that time is contained in D. J. X. Montgomery, Cosmic Ray Physics (Princeton Univ. Press, 1949).
5 The manner in which the counting rate of a simple Geiger-Muller counter varies as a function of altitude is described in many sources, including James A. Van Allen, “The Cosmic Ray Intensity Above the Atmosphere Near the Geomagnetic Pole,” II Nuovo Cimento (1953) pp. 630-647.
