CLAUDE MILTON GILLESPIE, JR. Dec. 13, 1932 – Oct. 1, 2025
Claude Milton “Milt” Gillespie, 92, passed away October 1 surrounded by his family. He lived a full and wonderful life devoted to outdoor adventure, intellectual curiosity, and most of all his family. The only child of Claude Milton Gillespie Sr. and Alice Hauer Gillespie of Huntsville, Alabama, Milt enjoyed childhood visits to the nearby family farm and told stories of mischief at nearby rivers and lakes.
He was fortunate to spend his high school years at Sewanee Military Academy, a college preparatory program located near Chattanooga, TN. His time at Sewanee launched his long career in national security and military affairs. After graduation, he attended the Georgia Institute of Technology (Georgia Tech), where he studied physics and mathematics, graduating in 1954. During this time in Atlanta, Milt met Marian Francis McElroy and they married in 1955.
After Graduating from Georgia Tech, Milt received his commission in the U.S. Airforce as a Second Lt. in 1956. While a young officer he participated in several nuclear bomb tests in the Pacific Islands and remembered vividly the sights and sounds and the resulting debris. After serving out his Air Force career at Kirtland Airforce base in Albuquerque NM, Milt returned to graduate school at Ohio State University where he earned a PhD in Physics in 1966.
Milt and Marian moved to Los Alamos in 1966 and Milt began a long career at LANL. Because of his military background, he was deeply involved with weapons design and development activities at LANL, ultimately serving as an assistant to the Associate Director for Weapons. He also served in X Division as the Associate Division Leader for Fusion and Plasma Applications. From 1983 to 1986, Milt was assigned to the Defense Nuclear Agency (DNA) in Washington D.C. During his time at DNA, he led the design, operation, and execution of a variety of tests at the Nevada Test Site which provided vital information on the survivability of military equipment. Additionally, he testified before Congress on the global effects of nuclear warfare and represented the Joint Chiefs of Staff during US/USSR nuclear testing talks.
After his time at DNA, Milt returned to LANL where he retired in 1993.
Milt and Kathryn (Kathy) met on a Sierra Club sponsored backpacking trip in California, and he often said she was like meeting an angel. Falling head over heels, he found many ways to visit Southern California so he could spend time with her. The two married in December 1972, each having been widowed with two children. Kathy with her two girls – Jeanne and Janet, and Milt with his two boys – Milton and Kenny, brought their families together under one roof in Pajarito Acres, the kids were 9, 10, 11, and 12.
Like many in their circle of friends, affectionately called, “the Rat Pack”, Milt took voluntary retirement in 1993, and ramped up the couple’s outdoor recreation by taking river trips in Canada, Alaska, and all over the lower 48. For most of his adult life, Milt volunteered at Pajarito Mountain, our local ski area. He served as Ski Club President, was a member of the Ski Patrol, and was instrumental in creating the snow grooming program, initially with a small bulldozer and a homemade roller. He also loved blowing up large and belligerent rocks with explosives on Wednesday nights.
Not long into their retirement, Milt and Kathy bought a place in Vail, Colorado, spending many weeks each year where they skied and hiked to their hearts’ content. Together they hosted their children and grandchildren and shared their love for that special place for nearly thirty years. Milt skied until the age of 89.
Milt was proceeded in death by first wife, Marian Frances McElroy Gillespie and parents C. M. Gillespie, Sr. and Alice Hauer Gillespie. He is survived by his wife of 53 years, Kathryn “Kathy” Ball Gillespie; son Milton Gillespie (Hollis Brookover) and grandson Samuel Milton Gillespie of Boise, Idaho; daughter Jeanne Gillespie (David) and granddaughter Andrea Kmetko of Santa Cruz, California; daughter Janet Estrada (Doug) and grandchildren Lanelle Ward, Jared Ferguson, Shauna Ferguson, Aven Furguson of Woodland Park, Colorado; and son Ken Gillespie (Joanna) and grandchildren Jordan Gillespie (Melissa) and Parker Gillespie of Los Alamos.
The family wishes to extend its sincere gratitude to Dr. Molly Vosburg, Los Alamos Visiting Nurse Service, the staff of Los Alamos Medical Center, with special mention to Deb Storms, and most especially to two caretakers Magnolia and Carrie who demonstrated immense compassion and excellent care. Services will be held at Bryce Avenue Presbyterian Church, where Milt was a member for more than 15 years, on Saturday October 25, 11:00am followed by a private committal at Guaje Pines Cemetery.
Donations to Hope Pregnancy Center in lieu of flowers.