Obituary of Charles (Chuck) Sonett (1924-2011)

US Army Naval Radiological Defense Laboratory Ramo-Wooldridge Corporation, Space Technology Laboratories division Chief of Sciences, NASA Lunar and Planetary Programs Director Space Sciences Division at NASA Ames Research Center Director Lunar and Planetary Laboratory (LPL), Dept. Chair Planetary Sciences, University of Arizona Regents’ Professor, University of Arizona

On September 30, 2011, Charles P. Sonett, second LPL director, first Planetary Sciences department head, and Regents’ Professor of Planetary Sciences Emeritus, died from complications of Parkinson’s disease. After graduation from high school, Sonett entered UCLA, majoring in physics. The Japanese bombing of Pearl Harbor in 1941 interrupted his studies. He enlisted in the Army on October 26, 1942. On March 13, 1945, while on combat patrol in France near Uhrwiller in Alsace, Sonett stepped on a German mine. His wounds required a battlefield amputation of his left leg. Sonett’s military decorations include the Combat Infantryman’s Badge, Bronze Star, and Purple Heart. After leaving service, Sonett returned to UCLA to continue undergraduate work in physics. He then transferred to the University of California at Berkeley where he graduated in 1948. In June of that year he married Virginia Louise Hooten, also a graduate of UC Berkeley. His first employment was with the Naval Radiological Defense Laboratory at Hunters Point, San Francisco, working in satellite planning. After one year he returned to UCLA where he received his Master of Arts in 1951 and Doctorate in 1954. Following his graduation, Sonett’s interest shifted from nuclear physics to rocketry and its application to exploration of the solar system. This change in interest coincided with the launch of Sputnik and the beginning of the “Space Race.” Sonett began employment with Ramo-Wooldridge Corporation, Space Technology Laboratories division. Sonett was subsequently employed at NASA Headquarters in Washington, D.C. where from 1960 to 1962 he was NASA’s Chief of Sciences, Lunar and Planetary Programs. In 1962 Sonett became the head of the Space Sciences Division at NASA Ames Research Center, where he oversaw research for the nation’s space program in the areas of geophysics, interplanetary and planetary physics, planetary sciences, astronomy, and astrophysics. He remained at Ames for 11 years; during that time he was principal investigator on Explorer 33 and 35, Lunar Orbiter Magnetometer Experiment. During the post-Apollo era, Sonett played an important role in efforts to understand the Moon’s interior through the use of magnetic field measurements at the Moon’s surface and from orbit. A major goal was to understand whether the Moon had a metallic core analogous to the Earth’s. Sonett worked with several collaborators to analyze spacecraft data using new theories for electromagnetic induction in the Moon. The results set firm limits on the electrical conductivity and hence the temperature profile of the Moon’s upper mantle. The culmination of this work at the University of Arizona during the late 1970s and early 1980s led to a firm upper bound of about 400 km for the radius of a highly electrically conducting metallic core in the Moon, proving a major dissimilarity of the Moon to the Earth. Sonett’s result is consistent with current estimates for the lunar core radius (about 330 to 350 km based on a variety of geophysical measurements). As a space exploration pioneer, Sonett was involved in the following programs and missions: Pioneer Program Missions included: Pioneer 1, launched Oct 11, 1958 Sonett, Principal Investigator, Ion Chamber and Single Axis Search-Coil Magnetometer Pioneer 2, launched November 8, 1958 Pioneer 5, launched March 11, 1960 Explorer Program A series of spacecraft missions that have studied the Sun, Moon, Earth and the environment of our Solar System. The first spacecraft was launched in 1959; the program still has many missions in operation: Explorer 6, launched August 7, 1959, Earth Explorer 33, launched July 1, 1966, Earth Explorer 35, July 19, 1967 Sonett, Principal Investigator, Ames Magnetic Fields Explorer Studied interplanetary space from lunar orbit and discovered that the Moon has no magnetosphere, that the solar wind impacts the lunar surface and that the Moon creates a ‘cavity’ in the solar wind. Apollo Program Manned missions to the Moon: Apollo 12, launched November 14, 1969 Sonett, Principal Investigator, Lunar Surface Magnetometer Results of these experiments indicated significant variations in the strength of the Moon’s magnetic field on both local and regional scales. Apollo 15, launched July 26, 1971 Apollo 16, launched April 21, 1972 Ulysses Program Joint ESA/NASA mission and first to survey of the Sun’s environment in space from the equator to the poles, and over a wide range of solar activity conditions, launched October 6, 1990 In 1969 Sonett received NASA’s Exceptional Scientific Achievement Medal for unusually significant scientific contribution toward achievement of aeronautical or space exploration goals. In 1973, Sonett was invited Sonett to be the director of the University of Arizona’s Lunar and Planetary Laboratory (LPL), and to head the new interdisciplinary Department of Planetary Sciences, chartered that year by the Arizona Board of Regents. During his term as the first Planetary Sciences Dept. Chair and second LPL director (1973-1977), Sonett presided over a dramatic expansion. He built research and education programs in solar system science that became internationally recognized. In 1992 Sonett was named Regents’ Professor, the highest academic rank at the University of Arizona. Sonett retired in 2003 as Regents’ Professor Emeritus. On April 30, 2004, the University of Arizona dedicated the Dr. Charles P. Sonett Space Sciences Building, which houses around 45 scientists and support staff. At the building’s dedication, Michael J. Drake, LPL Director at the time, stated, “Bringing Sonett to UA was one of Gerard Kuiper’s best moves. Chuck understood the breadth of what planetary sciences would become, and why it was important to hire first-rate people. He laid the roots of the modern lab---and what has become the best planetary sciences department in the world.” Remembrances may be sent to the Arizona Chapter American Parkinson Disease Assoc., 616 N. Country Club Road, Tucson, AZ 85716.