Douglas Charles Kubler

Douglas Charles Kubler of Thousand Oaks died at home on Tuesday, September 8, 2026, six days after his 82nd birthday. He was riding his bike when his heart stopped. It was quick, and it was where he was happiest.

Doug was born in Jackson, Mississippi, while his father, an Army Air Forces flyer, was on his 35th mission over Germany. He grew up an Air Force kid, and in Roswell, New Mexico, his adopted hometown, he and his pals rode their bikes everywhere, "without helmets, locks, or lights." He graduated from Caltech in 1966 with a degree in physics, was drafted the same year, and served in the U.S. Army, including in Germany.

He spent his career as a software engineer in aerospace, from satellite orbits and the display systems for the Viking Mars lander to twenty years at Hughes Aircraft, later Raytheon, building the tools behind the F-14, F-15, F-18, F-22 and B-2. He married Katherine "Kathie" Turner in 1970, and they raised five children in the same Thousand Oaks home for more than fifty years.

Retirement, he said, "just means you don't get paid." He rode nearly every day: 700 miles a month in his sixties, more than a million feet of climbing in a single year, the Vision Quest at 64 as the oldest rider in the field, and the Leadville 100, a hundred miles at ten thousand feet, at 70 and again at 72. He helped run the Nightrides mountain-bike group, gave away his trail maps and helmet-camera videos to anyone who wanted them, and was the person riders called when a bike, a GPS or a ride plan needed fixing. After a stroke in 2022 he came all the way back, still setting personal records in 2026.

He never stopped being a student. He wrote more than a hundred letters to the editor, most of them arguments from arithmetic. He photographed a mountain lion at ten feet and flew drones in his seventies. For the last ten years of his life he got up before dawn to work on a geometry theorem first posed in 1840, and this spring he was still arguing it with the editor of a mathematics journal. He signed his letters "Retired but active."

He told his sons to photograph everything, because "someday you'll be glad for the reminders." He was right.

Doug was preceded in death by his parents, Lt. Col. Edwin C. Kubler Jr. and Betty Lee Kubler. He is survived by his wife of 56 years, Kathie; his children, Kristina Turner (Jim), Kimberly Weixel (Steve), Robert Kubler (Brittany), Thomas Kubler (fiancée Amanda) and Elizabeth Kubler; his nine grandchildren, Dougie and Eddie; Jasper, Amber and Ember; Matthew, Harlow and Ivar; and Alexander; his sister, Kyla Law; his brother-in-law, Steve Turner; and the riding friends of forty years who knew him as the one who always knew how.

A funeral service will be held Friday, October 16, 2026, at noon in the chapel at Pierce Brothers Valley Oaks Memorial Park, Westlake Village, followed by burial with military honors.