[323-324] John L. Sloop retired from government service in 1972 after 31 years of aeronautical and space research and its management. He joined the National Advisory Committee for Aeronautics at its Langley laboratory in 1941, was transferred to its new engine laboratory in Cleveland in 1942, and headed a group working on aircraft engine ignition problems during World War II. After the war, he was placed in charge of cooling research in a newly formed section on rockets; he concentrated on internal film cooling using porous walls and other techniques. In 1949, he was made head of the laboratory's rocket research; during the 1950s his group made many contributions in theoretical and experimental research on high-energy propellants, ignition, combustion, and cooling. Over 150 technical reports were published by the rocket group by 1960.

Abe Silverstein, who initially headed all of the National Aeronautics and Space Administration's spaceflight programs, brought Sloop to Washington in 1960 as one of his technical assistants. Sloop served on a number of internal management committees on launch vehicles and spacecraft and participated in the planning that led to the Saturn vehicle and Apollo missions. A year later, he became deputy director of the group that managed NASA's small and medium launch vehicles (Scout, Delta, Atlas-Agena, and Atlas-Centaur). In 1962, he was named director of propulsion and power generation in NASA's office of advanced research and technology, where his responsibilities included solid- and liquidpropellant rockets and on-board power using chemical and solar energy. In 1964, Sloop became assistant associate administrator for advanced research and propulsion, of the office that managed research in NASA laboratories in the fields of aeronautics, space vehicles, propulsion, electronics, human factors, and basic research.

Sloop is the author of 45 publications and over a hundred unpublished papers and talks. He is a Fellow of the American Institute of Aeronautics and Astronautics and in 1974 shared its Goddard award with two others "for significant contributions to the development of practical lox-hydrogen rocket engines which have played an essential role in the Nation's space program and in the advancement of space technology." He is also a member of the Society for the History of Technology. He has held various offices in the American Rocket Society and the AIAA.

Sloop was born in Charlotte, N.C., in 1916, earned a B.S. in electrical engineering from the University of Michigan in 1939, and is a registered engineer in Ohio. Mr. and Mrs. Sloop (the former Atlasse Yeargin) live in Bethesda, Maryland. They have four children: Linda Carr (b. 1942), Lt. (jg) Wflliam Locke (1944-1969), Judith Farrell (b. 1946), and John Robert (b. 1948).