Don Owen Coffin made his transition from this world peacefully Sept. 27, 2026, in Los Alamos, New Mexico, in his apartment at Los Alamos Assisted Living, just after visiting with his family. He was 97.
Born June 27, 1929, Don lived a long and deeply rooted life marked by intellect, devotion, and steady character. He was valedictorian of Modale High School in Iowa, an early indication of his inquisitive nature and life-long dedication to learning more about the world around him. He then attended Simpson College in Iowa, where he studied mathematics and physics and was a member of the Epsilon Sigma Honors Society. He continued his studies at the University of Colorado in Boulder, earning a Master’s in Physics. While at Simpson, Don met and married (Sept 10, 1949) the love of his life, Lois Hamilton. By the time Lois passed away (March 16, 2026), they had been faithfully married for an astonishing 76-1/2 years!
Don began his professional career with the Bureau of Standards in Boulder, CO, while finishing up his master’s degree. A few days after returning from an interview with Sandia Lab, which included an immediate job offer, he was called for an interview at Los Alamos. The moment he flew into this beautiful mountain community, his heart was set on making Los Alamos home for his young family. LASL offered him a position, with even higher pay, so he immediately accepted. That decision shaped the course of his life, and he went on to raise his family, build a career there, and eventually retired from LANL after 33 years of service. He was highly respected in the field of cryogenics and tritium sciences and authored several scientific papers throughout his career.
Beyond his academic and professional accomplishments, Don was a man of wide interests and zest for life. In his youth, his favorite activity was bicycling. He was given his first bicycle at age 11, and it was his sole mode of transportation throughout his school years and undergraduate work at Simpson, earning him his class nickname of “Bi-Cycle.” He also enjoyed hiking, Scouting, camping and back-packing. This life-long love of the outdoors was passed on to both his daughters, as most of their family vacations were spent visiting and camping at National Parks all around the Southwest.
Though Don gave up bicycling during most of his work years in Los Alamos, he took it up again more seriously as he was approaching retirement. His wife Lois had reignited his desire to find a fun way to stay healthy and strong, when she signed them up to do a bicycling tour through southern Colorado. This provided a whole new way for them to travel and experience the beautiful country in which they lived. In his pre-retirement years, at age 50, Don also realized a childhood dream and earned his pilot’s license. He spent nearly a decade flying with Lois, along with the fold-up bikes that she encouraged him to buy so they could pedal from airport to hotel at the parks they were visiting. He later joined the BAC (Bicycle Adventure Club) and was eventually awarded a life-time membership for his dedicated years of support. He participated in many multi-day bike tours all over the US, Canada and Mexico. For several years, he even led what became a classic BAC tour here in northern New Mexico, called “The Anasazis to Atoms Tour,” aka “The NM Enchanted Circle Tour.” Don inspired his daughter Gracia and her husband Don Gettemy to take over this tour for a few more years, after he retired from leading bicycle tours himself.
For most of his retirement years, Don and Lois maintained a second home in Mesa, AZ and lived there during the winter months. In AZ, Don was a dedicated member of the Red Mountain Bike Club and the Pinnacle Peak Pedalers. He later inspired another group of senior cyclists to hold weekly rides in Los Alamos, White Rock, and the Rio Grande Valley, during his summer months in NM. By the time he hung up his bike for good, at the age of 89, he had logged nearly 150,000 miles in the saddle. His Los Alamos friends are still riding many of the routes he scouted for their weekly rides.
Another life-long love of Don’s was photography, especially nature photography. This love of photo-documenting life, the beauty of nature, and travel experiences was passed on to both his daughters. Also, having begun his work career just as computers were making the scene, Don enjoyed discovering practical as well as creative uses for his computer. After retirement, he avidly researched and pieced together his family genealogies. This included finding and digitally restoring old family photos, creating genealogy charts, and putting together various photo journals and albums for each of his family members. He also put together his own photo-historical autobiography, a kind of “time-capsule” of what was going on in the world during each of the chapters of his life. His computer was the perfect play-tool for these explorations in his retirement years. It also helped him maintain a sharp mind well into his 90s, as he always did his own taxes and even helped others do theirs by volunteering as a Tax Aid for AARP.
Those who knew Don will remember his sense of humor, his loyalty, and his unwavering integrity and honesty. He was devoted to his wife and family, and he carried a deep compassion for humanity along with a profound love of country. As a nature lover, he cared deeply about environmental protection and believed that staying active in the outdoors was essential for a happy and healthy body, heart and mind. These values were not simply interests to him, but part of the way he moved through the world. He was an “activist” not by preaching his politics to others, but by quietly modeling and walking his mind and heartfelt beliefs in the world, inspiring others to do the same. On the lighter side, his favorite life advice was “When it quits being fun, quit doing it!”
His birth date and date of death put together end to end forms a perfect palindrome (6272992726), which if he didn’t actually plan it that way, would certainly have been appreciated as one of the mathematical enigmas of his life. Don will be remembered as a thoughtful and accomplished man whose life joined intellect, principle, love of family, and appreciation for the natural world. His long life was truly a gift to his daughters and those who knew him, and his memory will remain a blessing to his family and friends.
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Don is survived by his daughters, Gracia Gettemy Coffin and her husband, Donald Gettemy, and Marcia Brown and her husband, Martin Brown. He also leaves his grandchildren, Jonathan Brown and Wendy Pettay and her husband, Michael Pettay, as well as his great-grandchildren, Gavin Brown, Tatum Brown, Hailey Pettay and Reagan Pettay. He is also survived by his younger sister, Colleen Wenham. His family was an important part of his life, and the generations that follow him carry forward the love, strength, and example he gave them. He was preceded in death by his beloved wife, Lois Coffin; parents, Owen and Thelma Coffin; and brother, Joe Coffin.
A Celebration of Life will be held at Los Alamos Assisted Living, 1010 Sombrillo Court in Los Alamos, at 2 p.m. MDT, Oct. 27, 2026. In lieu of flowers, our father’s memory would be honored by a donation to a local humanitarian project or organization, an organization focused on protecting our natural environment, or to your favorite charity.
Don Coffin with his wife Lois on a tandem bike. Courtesy photo
Please visit www.riverafamilyfuneralhome.com to leave pictures, stories and condolences for the family.