SPRL History: The Early Years

William Gould Dow and the Birth of SPRL

Soon after the end of the Second World War the United States' space program began in earnest: many captured German V2 rockets were launched in this post war era, both to study rocketry and to study the Earth's upper atmosphere. One of the first groups of scientists participating in this exciting period of discovery was the later-named Space Physics Research Laboratory, founded under the leadership of Professor William G. Dow of the University of Michigan's Department of Electrical Engineering.

Professor Dow was born in 1895 and received his B. S. from the University of Minnesota in 1916 and his E. E. from the same institution in 1917. He served as an Engineer in the U. S. Army at Fort Belvoir on the Potomac River during the First World War. After the Great War he worked in industry both as a practical power engineer and in marketing. In the late 1920s he left industry to return to academia, taking a position on the instructional faculty in the Department of Electrical Engineering at the University of Michigan in 1926, and completing his M. S. E. in 1929.

When the United States became involved in the Second World War, Professor Dow was called to serve his country in his field of Electrical Engineering. He conducted research into radar counter measures at the Harvard Radar Research Laboratory. It was during the war years that he was first exposed to the V2 rocket. As part of his war work he was sent to London, where he heard V2s dropping. In fact, one V2, landing in London, missed him by 5 minutes and 1/4 of a mile.

Once the war was over Professor Dow returned to his post at Michigan, becoming a full Professor in 1945. Another person who returned to Michigan after doing war-related research was Emerson Conlon, then Chair of the Department of Aeronautical Engineering. Professor Conlon had worked in the Naval Bureau of Aeronautics during the war, and so shared a common interest in Rocketry with Professor Dow. This common interest started the processes which lead to the foundation of the Space Physics Research Laboratory.

In January 1946 the Cold War was just around the corner. The belief existed in Washington that there was a need to stay ahead of other countries in the fields of applied science or the United States would lose the next war. For those involved in science education this attitude was very beneficial: to paraphrase Professor Dow, "Necessary equipment was readily available, and you could pay the going rates for those who were capable of using it. Unlike industry, the federal government was willing to allow you to learn not only how something occurs, but why it occurs. And they were also keen for you to publish."

Professors Dow and Conlon felt that the University of Michigan should participate in this heady research environment. So Professor Conlon contacted Air Force personnel at Wright Field toward the end of 1945 and in January 1946. Professor Conlon wanted to have a telemetry capability in the Department of Aeronautical Engineering and wanted to attract Myron Nichols to the University of Michigan to provide the necessary expertise.

Because of his familiarity with telemetry, Professor Dow attended a telemetry conference at Princeton University in January 1946. Myron Nichols hosted this conference, and through him Professor Dow found out that the Army and Navy had joined together to make use of the many captured German V2 rockets for research purposes. These rockets would come to represent a major breakthrough in upper atmospheric research. Prior to this time the highest in situ measurements possible had been made by balloons, which could only reach altitudes of only 30 kilometers. The V2 rocket could go up 100 miles!

The Army and Navy were pursuing this research in concert, but they had carefully excluded the Air Force, which had recently been split off from the Army. Their planning provided an opportunity for those wishing to get into rocket research. This opportunity existed because a crucial component of the Army and Navy plan for the development of rocket research in this country was originated in January 1946 as the Rocket Research Panel. Naturally, the Air Force was interested in pursuing rocket research and they could do so by getting a representative on the panel. Members of this panel had to be actively involved in some kind of tangible, experimental research.

Professor Dow's USAF connection now became useful. He went to the USAF and proposed to represent them on the Rocket Research Panel in exchange for their support. They offered him a contract and processed it in 30 days, clear evidence of their enthusiasm in this matter. Professor Dow attended the second meeting of the Panel as the official representative of the USAF. Later they brought in their own representative from the Cambridge Laboratory (which subsequently became the Air Force Geophysical Laboratory, then the Phillips Laboratory).

After this second meeting, Harold Zahl, another wartime colleague, and the Army's Signal Corps, decided that they needed a representative on the Rocket Research Panel. Professor Dow offered to arrange this through the University of Michigan. At the time it was arranged for Professors Dow and Conlon to send two unsolicited proposals to the Army's Fort Monmouth, N.J. laboratory one to work on microwave magnetrons and the other to develop instruments to be flown on a V2 rocket. In the same post, two one- year contracts arrived to do these pieces of work. The first contract lead to the formation of the Vacuum Tube Research Laboratory in the Department of Electrical Engineering (which still exists as the Center for High Frequency Electronics). The second contract was taken over by Myron Nichols, by then a member of the Department of Aeronautics. This latter contract was to become a source of mild friction between the Department of Aeronautics and the Department of Electrical Engineering, which was under contract to a different agency to perform similar work with the V2 rocket.

The Air Force contract with the Department of Electrical Engineering, which was awarded in March 1946, called for the instruments to be launched aboard a V2 rocket on August 22, 1946. The Air Force had decided to measure atmospheric temperature and density. Professor Dow also wanted to measure the electron and ion temperatures in the ionosphere, and had proposed to the Radio Propagation Laboratory of the Bureau of Standards to do so. The proposal was rejected, so he returned to the Air Force with it. They told Professor Dow to go ahead as long as it did not cost too much.

Now, with a budget and a launch date in hand, Professor Dow needed someone to do the work. Nelson Spencer and John Strand were employed to assemble the instruments. The University of Michigan's contribution to the rocket's instrument payload consisted of a thermionic vacuum tube, to measure neutral temperatures and densities, and a Langmuir probe to measure ion and electron temperatures. The thermionic vacuum tube was expected to produce valuable data from the rocket launch. Its weakness was that it did not perform well at low altitudes, but it was an accurate device in the region of primary interest for these rocket missions.

As originally planned, the launch occurred at 9 a.m. on August, 22 1946. Professor Dow recalls that the beginning of the launch of a rocket is a beautiful thing because, 'it moves so slowly.' The manager of the White Sands rocket range wanted to share the beauty of the launch with the people of nearby El Paso, whom he knew to be very interested in the V2 rockets. So he invited them to come watch the launch. One hundred and fifty people from El Paso accepted his invitation. They boarded buses, journeyed to White Sands, parked about a mile away from the launch site, and prepared to watch the show. But what they mainly saw was a second and more exciting show. Instead of going straight up, the rocket tilted at an angle. went up about 300 feet, leveled off, and then struck the Earth approximately one mile away from the launch site in an explosion of alcohol and liquid oxygen propellants. Luckily this explosion occurred 1/4 of a mile from the watchers from El Paso. It was the first and last time that guests were invited to watch a V2 launch.

Despite the failure, the USAF was willing to grant another contract to perform upper atmosphere research. They were a bit less enthusiastic this time and would not process it in just 30 days. The result of this second sponsorship was a successful flight in November 1946.

One result of this experimental work using rockets was a greater understanding of the temperature and density of neutral atmosphere up to 100 miles, knowledge that was to prove crucial in making re-entry calculations for manned spacecraft at a later date. Dr. Fred Whipple, then Director of the Smithsonian Astrophysical Laboratory and, as a member of the Rocket Panel, a colleague of Professor Dow's, had used observations of meteor trails to make an estimate of the neutral density based on the concept of the amount of air required to make them catch fire. He estimated that his prediction would be accurate within a factor of 10. Considering the almost total lack of knowledge about the region at the time, it was a very good estimate. He, no doubt, hoped that his estimates were more accurate than that. With the advent of the V2 rocket launchings, these densities could be measured directly.

Two instruments were flown which could make these measurements: one from the University of Michigan's Department of Electrical Engineering and the other from the Naval Research Laboratory. When the data were analyzed it was found that the NRL measurements were very close to Dr. Whipple's calculations and that the SPRL data differed by a factor of 10. When asked what he thought of this, Professor Dow replied that it was unlikely that Whipple's calculations were that accurate. As he suspected, three months later the scientists from NRL reported that they had corrected the calibration of their results. Their measurements were now essentially the same as those made by SPRL.

Such were the earliest events that lead to the birth of SPRL. Professor Dow continued his work in the Department of Electrical Engineering (serving as Chairman of the Department of Electrical Engineering from 1958 until 1964) until his retirement in 1965. In addition to the pivotal role he played in setting up SPRL, he played crucial roles in setting up both the Vacuum Tube Research Laboratory and the Willow Run Laboratory, which was later to become ERIM, a private company internationally known for its environmental research. Professor Dow's lifelong contribution to research was given formal recognition by the University of Colorado in 1980, when he was awarded an honorary Doctorate.