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Mon Dec 9 22:33:49 PST 2019

Volume XXVI, Issue 71


Table of Contents

1. John B. Cladis: 1922-2019


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John B. Cladis: 1922-2019

From: Steve Petrinec (steven.m.petrinec at lmco.com)

(The following obituary is taken from https://www.skylawnmemorialpark.com/obits/john-b-cladis/.)

Dr. John B. Cladis was a nuclear physicist who engaged in nuclear and space physics research for over 60 years. He passed away on September 12, 2019 at the age of 97. John was born in Dawson, NM on June 21, 1922 but moved to Denver Colorado shortly afterward. He was the son of Greek immigrants, Mary and George Mperos. His father died when John was 1 ½ years old, and he was adopted by his stepfather Tom Cladis. John was blessed with a wonderful family. His wife of 65 years Genevieve, whom he loved deeply, predeceased him. He is survived by his beloved children Mary Kay Worsley, Christine Billion, Dr. George Cladis and Dr. Mark Cladis, eleven grandchildren and three great grandchildren.

After obtaining a BS degree in engineering physics at Colorado University, John enlisted in the U.S. Army and served during WWII from 1941 to 1946. Following basic training in Camp Crowder, Missouri and Officer’s Candidate School in Ft. Monmouth, NJ, he was sent to Harvard and MIT to study courses pertaining to radar systems. Then he worked on advanced radars at Ft. Monmouth, NJ and taught radar principles and repair at Sea Girt, NJ. After VE day (May 5, 1945), John was sent to Italy, where he held several leadership positions at the Headquarters of the Mediterranean Theater of Operations in Caserta, Italy. He was fluent in Italian and served as a translator on several operations.

After his discharge from the army, John returned to Denver, CO and married Genevieve (Jenny) Liradjis, the love of his life. They moved to Berkeley, CA, where John did his graduate work in Nuclear Physics at the University of California and worked at the Lawrence Berkeley National Laboratory. Because of the invention by Dr. E. O. Lawrence of the cyclotron, which was then the highest energy machine in the world for investigations of new physics, the laboratory attracted great physicists. John loved his associations there, which included six Nobel Laureates, and was fascinated by a plethora of exciting ideas and the heralding in of newly created particles. John also made an important contribution by using the cyclotron to determine the velocities of nucleons in light nuclei, a finding that Nobel winner Emilio Segre said was the best research to come out of Berkeley. In 1951, after he received his PhD degree in Nuclear Physics, John went to work at the Los Alamos National Laboratory, where he helped develop a remote method of measuring the “burning rate” of exploding atomic and hydrogen bombs, an important measurement for the design of nuclear devices. He used this method to successfully test nuclear bombs in Nevada, Eniwetok and Bikini.

In 1955 John accepted an invitation to join a new movement at the Lockheed Aircraft Company to form a missiles and space division. He first worked on a proposal to develop a satellite reconnaissance vehicle. This proposal was accepted by the government only after the Sputnik satellite was placed in orbit by the Russians. John enjoyed working on the many new problems that arose during the development of the first large satellite. He quickly realized the need for testing the thermal design of satellites and, for this purpose, he designed a space thermal environment chamber that simulated the heating sources and sinks that a satellite would experience in an orbit about the earth. Because of its high cost, management was hesitant to build one, but now all satellite builders have thermo-vacuum chambers. John was honored by NASA as a Space Pioneer for his early work on spacecraft.

After the first satellite was successfully launched, John joined the Lockheed Research Laboratory in Palo Alto, CA and began working on the radiation belt that was discovered shortly before by Dr. James Van Allen. Using instrumented rockets, John contributed to the measurements of many features of the natural radiation belt and of the artificial radiation belts produced by the Argus high altitude nuclear explosions. In order to better understand plasmas in space, John went to Princeton University in 1961 to take courses in plasma physics. John was group leader, directing and performing space physics research for 51 years. He did such things as improving the understanding of the earth’s radiation belt; modeling the radiation belts interaction of the solar wind and the earth’s magnetic field; predicting the concentration of ions that would be knocked out of the moon’s surface by the solar wind and transported near the earth – a prediction was later confirmed by spacecraft measurements. Spacecraft measurements also confirmed his theory that heavy ions from the earth’s ionosphere would be accelerated by an electric-field-induced centrifugal force and move to high altitudes where they would form a component of the trapped radiation.

John lived a full life, filled with joy. He loved his family, his church, mathematics, physics, history, foreign cultures and music. He and his wife enjoyed attending international space physics meetings in many countries of the world since 1965 and had many friends and colleagues abroad. They also traveled often to Greece and Italy to visit relatives. John readily put to use the six languages he had mastered. He enjoyed playing the mandolin and the violin and sang in the church choir. He also sang songs in six languages.


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