Kathryn Thuleen's Obituary
Kathryn (Kathy) Thuleen passed away peacefully on April 18, 2026 at her home in Valley Center, California, surrounded by her family and loved ones, one week before her 90th birthday, after a long battle with metastatic breast cancer.
Born in 1936 in Minneapolis to Robin and Hildur Graves, Kathy met her future husband Ron Thuleen in junior high in Compton, California. Both attended UC Berkeley, where Kathy earned her degree in mathematics in 1957. She and Ron went on to celebrate 68 years of marriage.
Kathy joined the Jet Propulsion Laboratory as one of Helen Ling's "human computers," contributing to many space exploration projects including the Mariner missions. Her work and equations continue to be cited in satellite telemetry operations today. She left JPL when her youngest child was born, devoting herself to family life, and the family moved to Valley Center, California, where she and Ron cultivated first avocados and then grapes, turning the acreage into a beautiful vineyard and garden. An accomplished organist and pianist, Kathy served as the Valley Center Middle School chorus accompanist in the 1980s and early 1990s.
Kathy is remembered by all who knew her for her ever-present smile, her quiet competence, and her grace and cheer even in the face of adversity. She was a devoted mother and a gifted organizer, bringing people together throughout her life. In addition to gardening, she loved animals, music, her Swedish heritage, and the hand-made telescope she and Ron created. In her final days she watched the Artemis moon mission with rapt attention and delight.
Kathy is survived by her husband, Ron Thuleen of Valley Center; her son Rob, her daughter Nancy, her sister Janice, her brother Don, her grandchildren Anna and Alyssa, and a large extended family. She was preceded in death by her son David Thuleen (2019).
In lieu of flowers, the family welcomes donations to organizations supporting women in science and mathematics, or to breast cancer research.
What’s your fondest memory of Kathryn?
What’s a lesson you learned from Kathryn?
Share a story where Kathryn's kindness touched your heart.
Describe a day with Kathryn you’ll never forget.
How did Kathryn make you smile?