Simpson, John A. (John Alexander), 1916-2000

See the Guide to the John A. Simpson Papers for biographical information.

From the guide to the Simpson, John A.. Papers. Addenda, 1926-2002, (Special Collections Research Center University of Chicago Library 1100 East 57th Street Chicago, Illinois 60637 U.S.A.)

John Alexander Simpson was born November 3, 1916 in Portland, Oregon. His father, the youngest of five sons in Greenock, Scotland, came to Portland in 1910 and established a shoe and leather goods store. His mother, Janet Christie Brand, also from Greenock, was engaged to his father in Greenock and came to Portland to be married in 1914. A younger brother, William Brand, was born in 1919.

He married Elizabeth Alice Hilts in 1946. They had two children, Mary Ann born in 1954 and John Alexander in 1958. He was divorced in 1977 and married Elizabeth Scott Johnson in 1980.

Simpson’s early schooling, delayed by illness, was in public schools until he enrolled in Reed College, where he received an A.B. degree in 1940. He continued his study of physics with a scholarship and teaching assistantship at New York University at University Heights. He received an S.M. degree in 1942 and a Ph.D. degree in 1943.

After requesting an opportunity to help in the war effort, Simpson received a visit in 1942 from Volney Wilson of the University of Chicago, an assistant of Arthur Holly Compton. Compton was then director of the Metallurgical Laboratory devoted to producing a nuclear chain reaction and to producing plutonium for a nuclear bomb. Wilson encouraged Simpson to develop new radiation detectors which could be used to measure radiation of high intensity. In 1943, at the invitation of the Comptons, Simpson was given a room on the top floor of their home and was soon a scientific group leader for novel instrumentation and measuring methods required for the support of the ongoing work at Chicago, Oak Ridge, and Hanford.

In 1945, Simpson requested permission to hold weekly seminars on the international control of atomic energy in Ryerson Hall. These seminars and discussions with senior physicists in the Metallurgical Laboratory resulted in the formation of the Atomic Scientists of Chicago in August 1945, with Simpson as Chairman. Soon thereafter similar organizations appeared at Oak Ridge and Los Alamos. Simpson participated in founding the Bulletin of the Atomic Scientists in 1945 and was its first chairman. The activities of the scientists’ movement in Washington, D.C. in the fall of 1945 through the spring of 1946 were important for the establishment of a civilian bill for the control of atomic energy.

In August 1945 Simpson accepted, along with about ten other physicists and chemists, an appointment in the newly-formed Institute for Nuclear Studies (now the Enrico Fermi Institute), at the University of Chicago, as well as a joint appointment as instructor in the Department of Physics and the College. Subsequently, his join appointments included: Professor (1947), Associate Professor (1949) and Professor (1954). In 1968 he became the Edward L. Ryerson Distinguished Service Professor and in 1974 the Arthur H. Compton Distinguished Service Professor. Since 1987 he has been the Arthur H. Compton Distinguished Service Professor, Emeritus.

Among his administrative appointments, Simpson served as Chairman of the Committee on Instruction and Biophysics (1951-1952) and Director of the Enrico Fermi Institute (1973-1978). In 1962 he founded the Laboratory for Astrophysics and Space Research in the Enrico Fermi Institute.

Simpson’s scientific career began as an undergraduate at Reed College where, for a senior thesis in 1939, he designed and constructed a two-stage electron microscope. The original aspects of that work were published by him in his first two publications. After World War II he began investigations of the energy spectrum of the primary galactic cosmic ray protons by means of their production of a secondary nucleonic component cascade in the atmosphere. Using the fast neutron production as a tracer of the nucleon cascade he discovered the existence of the large latitude dependence of the cascade, the production of which was shown to extend to very low primary particle energies. From these studies Simpson invented in 1948 the concept and instrumentation called the neutron monitor pile, based on the early nuclear chain reaction at Chicago, which for the first time enabled the investigation of the time-dependent intensity changes of the very low energy primary cosmic ray nucleon component. His studies of the time dependence of the nucleonic component over a wide range of incident particle energies led to the proof that the cosmic ray intensity variations were due to interplanetary electrodynamical processes of solar origin-called the solar modulation of the galactic cosmic rays. In 1950-1951 he established a network of these neutron monitors extending from the geomagnetic equator to high latitudes. It was his neutron monitor network which recorded the flare of February 23, 1956 leading to his demonstration with colleagues Peter Meyer and Eugene Parker that there existed a large-scale heliosphere of magnetic fields surrounding The Solar System.

Simpson’s neutron monitor design became the world standard for cosmic ray research sponsored by the 68 nations participating in the International Geophysical Year in 1957-1958.

Beginning with the Office of Naval Research’s sponsorship in 1946, Simpson’s early research was mainly supported by ONR and the U.S. Air Force. This enabled him to undertake high altitude measurements with B-29 and RF-80 aircraft, and to use U.S. Navy icebreakers for investigations around the world extending from the magnetic equator to high latitudes. Simpson worked along at first and later with graduate students. He brought Peter Meyer to Chicago in 1953 and Eugene Parker in 1955 to expand the range of his researches, largely supported by federal funds. Following the launch of the first U.S.S.R. satellite in October 1957, U.S. rockets and satellites were made available for civilian scientific research beginning in 1958, which enabled Simpson to undertake the development of an expanded laboratory and novel instrumentation to attack problems in cosmic rays, interplanetary phenomena and solar accelerated particles directly in the interplanetary medium and the trapped radiation belts of Earth. His first spacecraft experiment was on Pioneer 2, November 1958 (see “Satellite and Space Probe Missions,” p. 6).

It was in the period 1958-1960 that Simpson laid out his three interrelated areas of research goals in space and programs to achieve them:

1) The investigation of the acceleration mechanism of charged particles in nature on all astrophysical scales

2) Using charged particles as probes for the electrodynamical processes in astrophysical settings-interstellar, interplanetary, heliospheric, and planetary magnetospheres, and

3) The investigation of the origins of isotopic and chemical composition of matter measured in galactic cosmic rays, solar flares, comets and the nucleosynthesis in stars.

This “triad” of astrophysical problems-all intimately interconnected and based on his earlier researches-were to be his principal guide for experiments and theoretical research for more than thirty years. This involved space-based research between 1958 and 1990, with Simpson acting as principal investigator for more than 30 experiments. These experiments were carried on spacecraft sent to Mercury, Venus, Earth, Mars, Jupiter and Saturn-as well as to comet Halley and into the third dimension of the heliosphere. All of Simpson’s research was conducted with the strong participation of his graduate students. His space missions provided the these for most of the 32 Ph.D.s awarded to students under Simpson’s supervision. He required that each Ph.D. thesis be published as a sole author contribution.

His experimental program in space would not have been possible without his development of a strong technical, and then later administrative, infra-structure. Simpson oversaw the creation of a solid state sensor laboratory in 1959 and the recruitment of a dedicated technical staff, which could transform original designs and models into flight-worthy instrumentation. Other components of the infra-structure included software development, computing, and data analysis. All of these factors were brought together in the LASR’s building, funded by NASA in 1962 and in full operation by 1964. Recognizing that his work represented modest-scale fundamental research in a university setting but that the space missions for carrying out these experiments were very large-scale efforts, Simpson evolved a style for the conduct of original research. This style was intended to interface small, fundamental science in the university with the big science aspects of major science missions. This included missions to the planets where many individuals and organizations were required by NASA to interact with the Principal Investigator. Simpson published his concept of conducting original and successful space science programs in a university setting, which integrated the work of students, technicians, and research scientists (see papers 12B, 13B, and 14B in Simpson’s publication list).

In support of these concepts for the conduct of space science NASA provided “Technology for Science” grants to LASR faculty from the mid-1960s to the early 1980s. These grants enabled Simpson and his colleagues to develop new concepts, including Simpson’s invention of polyvinylidene fluoride polymer sensors for detection of super heavy charged particles or mass measurements of dust particles in the coma of Comet Halley (1986). This technology support, plus the sequence of discrete space missions, provided a sustaining level of support for his group in LASR. The ability of his laboratory to respond rapidly to new opportunities is illustrated by the Vega missions. Simpson invented his dust detector in 1983 and it was incorporated into an instrument in the spacecraft and launched in 1984.

Federal support from ONR and the USAF continued into the 1960s, along with the new space agency, NASA, until Congress passed the Mansfield Amendment requiring that all Department of Defense support to universities be related to direct military objectives. At this point, Simpson refused to compromise the university’s research program and realigned his research support through NASA and the National Science Foundation.

There were two major periods where NASA was unable to provide access to space for Simpson’s experiments. The first period was 1960-1962 (marked by the failure of the Ranger missions). In this interval Simpson obtained three space flights by riding experiments “piggyback” on military missions-i.e. the Discoverer series. The second interval, approximately 1976-1989, was caused mainly by NASA’s ill-fated decision to discontinue expendable launch vehicles and to concentrate on shuttle launches. The Challenger accident in 1986 accentuated this problem. For this period Simpson again turned to ONR for non-funded sponsorship of NASA-financed instruments to be carried unclassified on U.S. Air Force missions. This period also saw the initiation of the out-of-the-ecliptic mission, realized first as the “ESA/NASA International Solar Polar Mission” and later as the ESA spacecraft designated Ulysses. This was a mission which Simpson had been urging NASA to undertake since the early 1960s and one where he and his staff had developed the required instrumentation in the 1960s and 1970s (see “Chart of CRRES and Ulysses Missions,” p. 12).

Although this period was a difficult one for gaining access to space for new missions, it continued to be a productive and creative period for research. Pioneer 10, Pioneer 11, IMP 7, IMP 8, and Mariner 10 (along with neutron monitors in Peru and Colorado) constituted a heliosphere “laboratory” for astrophysical investigations covering the triad of objectives noted above.

Since the deep space missions were mainly justified by planetary encounters, Simpson designed his experiments to take advantage of both their interplanetary travel phase and, by suing different sensors or operational modes, the planetary encounters to study planetary magnetosphere particle acceleration. Continuous observations and investigations over four successive 11-year periods of solar activity and more than one and one-half solar magnetic cycles have provided a unique set of data for investigating both high energy astrophysical phenomena surrounding a typical rotating magnetic star and for galactic cosmic ray studies.

The writings listed in Part B of Simpson’s publication list reflect Simpson’s personal view that scientists have an obligation to use their knowledge and approach to the solution of problems to influence national and international efforts for controlling the use of nuclear weapons and for promoting cooperation among nations. This view accounts for his extracurricular activities on behalf of the peaceful uses of nuclear energy, as well as his participation in the 68 nation International Geophysical Year as one of its twelve science organizers during the period of the so-called Cold War. It also was a factor in the pre-glasnost cooperative space effort to Comet Halley on two Soviet spacecraft. His support for the participation of universities in the U.S. civil space program led to his organizing the Space Science Working Group in Washington, D.C. in 1982.

From the guide to the Simpson, John A. Papers, 1940-1988, (Special Collections Research Center University of Chicago Library 1100 East 57th Street Chicago, Illinois 60637 U.S.A.)