Thomas Kelsall, who was deputy principal investigator on the NASA team credited with developing technology that yielded proof that the Big Bang Theory was correct, died in hospice care in Mitchellville, Md., on Aug. 13. Formerly of East Hampton, he was 89 and had had complications of dementia.
Working at NASA’s Goddard Space Flight Center from 1958 to 2003, Dr. Kelsall was a designer of the Diffuse Infrared Background Experiment, which was integrated onto the Cosmic Background Explorer (COBE) mission satellite. Between 1989 and 1994, the experiment provided extraordinary evidence, in the form of temperature fluctuations, that supported the Big Bang Theory. Stephen Hawking, recognized as one of the greatest scientific minds in history, later called the COBE results “the most important discovery of the century, if not of all time.”
Tommy Kelsall, as he was known here, was born in Southampton on Oct. 26, 1933, to Bernard Kelsall and the former Hilda Wilman. He graduated from East Hampton High School in 1951, and went on to earn a bachelor’s degree in physics from Muhlenberg College in Allentown, Pa., an M.S. in physics at George Washington University in Washington, D.C., and, in 1971, a Ph.D. in astronomy from the University of Maryland.
Over the years, Dr. Kelsall held engineering, research, data science and analytics, and management positions for NASA. He was recognized with several individual and group awards, including NASA’s Exceptional Achievement Award in 1990, the Smithsonian Institution’s National Air and Space Museum Trophy for Present Achievements in 1991, and the NASA Exceptional Scientific Achievement Award in 1992. He was honored three times with peer awards for his work on the space telescope program, a balloon-borne-telescope survey of the Milky Way galaxy, and his work for the COBE mission.
He married Ann Nottingham, an academic researcher, in June 1955. She survives.
Beyond his scientific interests, Dr. Kelsall was a member of committees that oversaw real estate development in Prince George’s County, Md. He read and wrote poetry, according to his extensive NASA C.V., taking part in the Squared Circle Poetry Round Table from 1955 to 1960 and serving as an editor and publisher of Trigram, a magazine, from 1956 to 1959. He loved animals, his wife said, cats in particular.
His many outside pursuits also included tennis, chess, and motorcycles. He was an officer of the Greater Washington Tennis Association from 1971 to 1976 and of the Landover Hills Recreation Council from 1975 to 1982. He was secretary and treasurer of the Goddard Chess Club and held leadership and organizational roles within the Goddard Tennis Club. For two decades, beginning in 1974, he was a trip leader for the Motorcycle Trippers, and traveled far and wide on his Honda Gold Wing.
In East Hampton, he was a member of St. Luke’s Episcopal Church.
In addition to his wife of 68 years, Dr. Kelsall leaves a nephew, Dafydd C. Corbett-Kelsall of Boca Raton, Fla. The family has suggested memorial donations to the physics department of Muhlenberg College, online at muhlenberg.edu/academics/physics.