H. GRADY HUGHES III Dec. 18, 1945 – Oct. 9, 2023

Henry Grady Hughes III passed away at home on October 9, 2023, following a long struggle with Parkinson’s Disease. Grady was born December 18, 1945, in Waco, Texas to Alice Vernor Hughes and Col. Henry Grady Hughes, Jr.

He spent his early years in Waco where his mother worked as a circuit court reporter. His mother traveled with the court to small towns in Texas, leaving Grady in the care of his grandparents, Mr. and Mrs. Harvey D. Vernor. Grady’s family moved to Houston in 1955 where his mother found work that did not involve traveling.

As a young child Grady was fascinated with the planets and made a small book with a page for each planet and all the facts he could find about each one. While still an elementary school student Grady began piano lessons and later took clarinet and saxophone lessons, becoming proficient in those as well as the piano. In high school he joined the church choir. Grady participated in his high school’s marching band and various performances of the high school orchestra. He became a National Merit Finalist and was accepted by numerous universities for his graduate work. 

It was no surprise that Grady, being deeply interested in science, focused on physics and cosmology as a student at Rice University. He went on to study physics at Rice University through the Ph.D. level. Grady then entered the post-doctorate program at the University of Maryland. As part of his post-doc training, Grady accompanied his professor to Oxford University in England, Les Houches in France, and Cal Tech in California, where he met many of the top scholars in his field.

He joined Los Alamos Scientific Laboratory (later Los Alamos National Laboratory) in 1975, where he studied cosmology. For much of his career at Los Alamos, Grady was a developer on the MCNP Monte Carlo particle transport code team. He was internationally respected as an expert in electron and charged particle transport simulation and was often an invited speaker at international conferences. 

Grady enjoyed traveling and traveled extensively to many conferences around the world and continued to work with some of the scientists he met there. He was a forward thinker and ensured that the MCNP software would continue to benefit the scientific community in future decades by devoting significant effort to modernizing the MCNP code. He happily shared his knowledge with anyone wanting to learn more, whether they were new members to the team or students at one of the many MCNP code classes that he taught. 

Grady loved the mountains of New Mexico and working at the Lab in Los Alamos. He enjoyed it so much that he worked there for 45 years and retired only when his Parkinson’s Disease began to interfere with his ability to get to work.  

In addition to his professional work, Grady presented piano recitals in his early days at Los Alamos and in Taos and sang in the Los Alamos Choral Society. As time went on he developed interests in scuba diving, free diving, skiing, and hiking and above all became deeply involved in live theater both in Los Alamos and Santa Fe. He starred in many plays including Twelfth Night, Macbeth, A Christmas Carol, A Winter’s Tale,  Harvey, The Notebook of Trigoran, Of Mice and Men, and many others. He also did sound design for plays in Los Alamos and Santa Fe. He and his wife, Betty Ann Gunther, traveled to see five total eclipses of the Sun.  

Grady was preceded in death by his mother, Alice Vernor Hughes, and his father Colonel Henry Grady Hughes. He is survived by his wife, Betty Ann; his son, David Hughes; his granddaughter, Marianne; cousins, Brenda and Rusty; and two half-sisters and two half-brothers.

A memorial service will be announced at a later date.