Leon Theodore "Lee" Silver (April 9, 1925 – January 31, 2022) was an American geologist who was professor of geology at the California Institute of Technology (Caltech). He was an instructor to the Apollo 13, 15, 16, and 17 astronaut crews. Working with the National Aeronautics and Space Administration (NASA), he taught astronauts how to perform field geology, essentially creating lunar field geology as a new discipline. His training is credited with a significant improvement in the J-Mission Apollo flights' scientific returns. After the Apollo program, he became a member of the United States National Academy of Sciences in 1974. He retired in 1996 as the W. M. Keck Foundation Professor for Resource Geology, emeritus, at Caltech.
Early life and education Silver was born in Monticello, New York, on April 9, 1925, as the youngest of five children.Cohen, pp. ii-iii His parents were immigrants from Russia and Poland, who moved the family to Waterbury, Connecticut soon after he was born. He graduated from Crosby High School in 1942.
After spending a year at the Colorado School of Mines before being called up by the Navy in 1943 as a member of the Navy V-12 Program, Silver earned his B.S. in civil engineering at the University of Colorado Boulder in 1945. He later earned an M.S. in geology at the University of New Mexico in 1948 and a Ph.D. in geology and geochemistry at the California Institute of Technology in 1955.Ph.D. thesis: Leon Theodore Silver, The structure and petrology of the Johnny Lyon Hills area, Cochise County, Arizona: California Institute of Technology, Pasadena, .
Career Early career Silver served in the United States Navy from 1943 to 1946, where he attained the rank of Lieutenant Junior Grade in the Civil Engineer Corps. He worked for the United States Geological Survey (USGS), Mineral Deposits Branch, in Colorado and Arizona from 1947 to 1954 (field seasons only), where he attained the status of Assistant Geologist.
Academic career After completing his Ph.D., Silver was appointed Assistant Professor of Geology (1955–1962) at Caltech; he was later promoted to Associate Professor (1962–1965), Professor (1965–1983), and W. M. Keck Foundation Professor for Resource Geology (1983–1996). After his retirement, he had been Keck Professor Emeritus.
His main research interests were petrology, tectonics, and applications of geology and isotope geochemistry to geochronology, crustal evolution, ore deposits, and comparative planetology. While pursuing these research interests, Silver also played a major role in the Apollo Program's lunar geological exploration as well as on numerous national scientific advisory boards and committees.
NASA and Apollo Program involvement NASA's Johnson Space Center Oral History Project lists Silver's involvement as follows:Butler (2002)
Geologist, Astrogeology Branch of the U.S. Geological Survey, (1970–1976, part-time), contracted to work with NASA Geology Lecturer to NASA Scientist-Astronaut Classes, Manned Spacecraft Center, Houston, Texas (Part Time 1968–1993) Lunar Surface Geology Experiment Team (Apollo 13–17) Lunar Sample Preliminary Examination Team (Apollo 15–17) Lunar Surface Traverse Planning Team (Apollo 15–17) Lunar Science Working Panel (Apollo 15–17) Lunar Sample Analysis Planning Team, Manned Spacecraft Center, Houston, Texas (1972–1974) Space Program Advisory Council Ad Hoc Subcommittee on Scientist-Astronauts (1974–1975)
Other federal government advisory roles Chairman of the Advisory Committee to the Office of Basic Energy Sciences of the Department of Energy (1990–91 and 1991–92)Membership of Basic Energy Sciences Advisory Committee Member of the Steering Committee of the NASA Synthesis Group, which evaluated mission scenarios for the President's Space Exploration Initiative (1990-1991)See America at the threshold: report of the Synthesis Group on America's space exploration initiative, Thomas P Stafford, Washington, D.C.: Superintendent of Documents, U.S. Government Publishing Office . . Member of the President's Advisory Committee on the Redesign of the Space Station (1993)"Final Report to the President: Advisory Committee on the Redesign of the Space Station," June 10, 1993.
In popular culture Silver's work with the Apollo Program has been recounted in Andrew Chaikin's A Man on the Moon (1994). The book became a TV mini-series in 1998, with David Clennon portraying Silver in the HBO docu-drama series From The Earth To The Moon. In the series' Episode 10 "Galileo Was Right," Silver is shown teaching the Apollo 15 astronauts field geology, and participating from Houston's Mission Control in their lunar extra-vehicular activities (Moonwalks).Drexler (1999) Silver was interviewed about the episode and he felt that it "romanticized" the experience, and had minor historical inaccuracies, but otherwise liked it and showed it at a lecture in 1999.
In 2006, Apollo 15 Commander Dave Scott devoted a section of his co-authored book Two Sides of the Moon to the training and instruction that Scott and other Apollo astronauts received from Silver.
Personal life and death Silver was a board member of the Caswell Silver Foundation at the University of New Mexico. The Foundation was created in 1980 through an endowment by Caswell Silver, an alumnus of the Department of Geology, independent oilman, and Leon Silver's brother. The Foundation supports education and research at the Department of Earth and Planetary Sciences at the University of New Mexico. He died on January 31, 2022, at the age of 96. His grandnephew is statistician and journalist Nate Silver.
Honors and awards In 1971 Silver was awarded a NASA Exceptional Scientific Achievement Medal both for his training of Apollo astronauts in geologic science and equally for his research:
For his significant scientific achievements in the development of highly precise isotopic compositions of uranium and lead in minerals and the applications of the age determination procedures in the analyses of lunar material. While diligently conducting these laboratory investigations of lunar material, he provided a major contribution by training the astronauts in geological sciences which, through his enthusiasm, leadership and guidance, has led to the successful exploration of the moon.
Guggenheim Fellowship (1964) NASA Exceptional Scientific Achievement Medal (1971) NASA Group Achievement Award, Lunar Traverse Planning Team (1971) NASA Group Achievement Award, Crew Training and Simulation Team (1971) American Institute of Professional Geologists Award for Professional Excellence (1972) NASA Group Achievement Award, Lunar Landing Team (1973) NASA Group Achievement Award, Earth Resources Experiment Team (1974) NASA Group Achievement Award, Lyndon B. Johnson Space Center (1974) Member, National Academy of Sciences (elected 1974) Senior Fellow, Mineralogical Society of AmericaList of Fellows of MSA President, Geological Society of America (1979)Eckel, Edwin, 1982, GSA Memoir 155, The Geological Society of America — Life History of a Learned Society: Boulder, Colorado, Geological Society of America Memoir 155, 168 p., . Centennial Distinguished Alumnus Award, University of New Mexico (1989)
Selected publications Silver, L.T., S. Deutsch, and C.R. McKinney, "Fusion Loss of Lead in the Analysis of Zircons for Isotopic Age Dating," Journal of Geophysical Research, Volume 64, Number 8, pages 1124–1124. (1959). Allen, Clarence R., Leon T. Silver, and Francis Greenough Stehli. Agua Blanca Fault: A Major Transverse Structure Of Northern Baja California, Mexico. New York: The Society, 1960. Silver, L.T., C.R. McKinney, and S. Deutsch et al. "Precambrian Age Determinations of Some Crystalline Rocks of the San Gabriel Mountains of Southern California," Journal of Geophysical Research, Volume 65, Number 8, pages 2522–2523. (1960). Silver, L.T., "Major Magmatic Events and Geochronology," Journal of Geophysical Research, Volume 66, Number 8, pages 2560–2560. (1961). Silver, L.T. "Older Precambrian Geochronology in Cochise County, Southeastern Arizona," Journal of Geophysical Research, Volume 67, Number 4, pages 1657–1657. (1962). Leon T. Silver and Sarah Deutsch. "Uranium-Lead Isotopic Variations in Zircons: A Case Study," The Journal of Geology, Volume 71, Number 6 (November 1963), pages 721–758. Silver, L.T., C.R. McKinney, and S. Deutsch et al. "Precambrian Age Determinations in the Western San Gabriel Mountains, California," Journal of Geology, Volume 71, Number 2, page 196ff. (1963). Cooper, John Roberts, and Leon T. Silver. Geology And Ore Deposits Of The Dragoon Quadrangle, Cochise County, Arizona. Washington, DC: U.S. Government Printing Office, 1964. R. T. Pidgeon, James R. O'Neil, Leon T. Silver. "Uranium and Lead Isotopic Stability in a Metamict Zircon under Experimental Hydrothermal Conditions, Science, New Series, Volume 154, Number 3756, pages 1538–1540. (December 23, 1966). Duke, Michael B., and Leon T. Silver. 1967. "Petrology of eucrites, howardites and mesosiderites," Geochimica et Cosmochimica Acta, Volume 31, Issue 10, October 1967, pages 1637–1665. Silver, Leon T., "Uranium-Thorium-Lead Isotope Relations in Lunar Materials," Science, New Series, Volume 167, Number 3918, The Moon Issue, pages 468–471. (January 30, 1970). Silver, L.T., "Lead Isotopic Heterogeneity in Lunar Soil 10084,35 and Its Age Implications," Transactions of the American Geophysical Union, Volume 51, Number 4, page 348ff. (1970). Silver, L.T., and M. B. Duke, "U-Th-Pb Isotope Relations in Some Basaltic Achondrites," Transactions of the American Geophysical Union, Volume 52, Number 4, page 269ff. (1971). Silver, L.T. "U-Th-Pb Isotope Systems in Apollo-11 and Apollo-12 Regolithic Materials and a Possible Age for Copernicus Impact Event," Transactions of the American Geophysical Union, Volume 52, Number 7, page 534ff. (1971). Silver, L.T., "Regional Provinciality in the U-Th-Pb Isotope Systems in lunar Soils," Transactions of the American Geophysical Union, Volume 54, Number 4, pages 349–349. (1973). Silver, L.T., and Anderson, T.H., 1974, "Possible left-lateral early to middle Mesozoic disruption of the south-western North American craton margin," Geological Society of America Abstracts with Programs, Volume 6, Number 7, pages 955–956. Silver, L.T., "Implications of Volatile Leads in Orange, Grey and Green Lunar Soils for an Earth-Like Moon," Transactions of the American Geophysical Union, Volume 55, Number 7, pages 681–681. (1974). Silver, L.T., "Thorium-Uranium Fractionation as an Indicator of Petrogenetic Processes," Transactions of the American Geophysical Union, Volume 57, Number 4, pages 353–351. (1976). Anderson, T.H., and Silver, L.T., "U-Pb isotope ages of granitic plutons near Cananea, Sonora," Economic Geology and the Bulletin of the Society of Economic Geologists, Volume 72, pages 827–836. (1977). Silver, L.T., and T.O. Early. "Rubidium-Strontium Fractionation Domains in Peninsular Ranges Batholith and their Implications for Magmatic Arc Evolution," Transactions of the American Geophysical Union, Volume 58, Number 6, pages 532–532. (1977). Silver, L.T. "Regional Uranium Anomaly in Precambrian Basement of Colorado Plateau," Economic Geology, Volume 72, Number 4, pages 740–741. (1977). Anderson, T.H. and L.T. Silver, "The role of the Mojave-Sonora megashear in the tectonic evolution of northern Sonora," The role of the Mojave-Sonora megashear in the tectonic evolution of northern Sonora. Silver, Leon T. "Problems of Pre-Mesozoic Continental Evolution," in B. Clark Burchfiel, Jack E. Oliver, and Leon T. Silver, Eds., Continental Tectonics, National Research Council, National Academy of Sciences, 1980, Chapter 2: pages 26–30.