John M Dahlen

John M. Dahlen, of Duxbury, passed away peacefully on Sunday, December 14, 2025, at the age of 95. He was the patriarch of the Dahlen family and is remembered with deep love by his large and devoted family, which includes eight children, twenty-two grandchildren, and thirty-one great-grandchildren.

John was born in Boston to Clarence ("Del") and Alice (Brooks) Dahlen and was raised first in Watertown and later in Braintree. His father died of pneumonia in 1935, and his mother, then pregnant with his sister Claire, moved the family to Somerville. In 1937 she married George Marshall, and John enjoyed four additional siblings.

From a young age, John aspired to become a Navy pilot. While a senior at Somerville High School, he was accepted into the highly competitive Navy pilot training program and was sent to MIT. After two years, he entered active flight training but was forced to leave the program after failing a routine eye examination-an immense disappointment. John then returned to MIT and completed his degree in Aeronautical Engineering.

It was during this period, after his family had relocated to Cochituate, that John met the love of his life, Sheila. They married upon his graduation. John was commissioned as a second lieutenant in the U.S. Air Force, and the couple moved to Wright Air Development Center, where they spent two years. The Air Force later sent John back to MIT to earn an advanced degree in Aeronautical Engineering, followed by a three-year assignment in California working in the Ballistic Missile Division.

After leaving the Air Force, John returned to Massachusetts and settled in Concord, where he joined the MIT Instrumentation Laboratory. There, he worked on guidance and navigation systems for the nation's early manned spaceflight programs, including Mercury, Gemini, and Apollo. In 1959, John joined the Charles Stark Draper Laboratory in Cambridge, where he continued work on the space programs.

In 1962, John and Sheila moved their growing family-by then six of their eventual eight children-to an old colonial home on Tremont Street in Duxbury. The house required extensive renovation, which became a labor of love. It was also during this time that John developed a lifelong passion for the ocean and sailing.

In 1967, John transitioned from space exploration to ocean science at Draper. He spent the remainder of his professional career there, leading the Oceanographic Instrumentation Research Laboratory until his early retirement in 1992. His work resulted in several patents for innovative ocean-measurement systems.

In 1970, John and Sheila purchased ten acres of shorefront property on Deer Isle, Maine, beginning a long-term family project to build a homestead for future generations. They first constructed a barn boathouse, followed by a post-and-beam Cape-style home of their own design. Although they never formally retired there, the property became a beloved family compound enjoyed by relatives and friends alike.

During these years, John also returned to flying, eventually becoming an instrument flight instructor. Later, seeking a new challenge, he devoted himself fully to sailing. Ever the engineer, John approached boating as a series of projects-spending far more time repairing and improving his boats than actually sailing them.

John was predeceased by his beloved wife, Sheila Patricia (Noonan) Dahlen; his sons Shawn Dahlen of Duxbury and Hugh and Brent Dahlen of Kingston; and his granddaughter Katrina Garvey of Duxbury. He is survived by his children: Colleen Dahlen of Plympton; Colin Dahlen (Loryn) of Kingston; Maura Garvey (Paul) of Duxbury; Neal Dahlen (Lorrie) of Marshfield; and Deirdre Dahlen of Kingston. He is also survived by his brother George Marshall (Brenda) of Dunstable; his sister Martha Walsh (Jim) of New Hampshire; twenty-one grandchildren; and thirty-one great-grandchildren. He was predeceased by his sisters Claire Hanson (Bob), Brenda Snider (Ron), and Sara Ceurvels (Edward).

A funeral Mass will held on Friday, December 19 at 11am at Holy Family Church in Duxbury, followed by private burial at Mayflower Cemetery. A celebration of life Mass will be held in late March, with family and friends to be notified. In lieu of flowers, donations may be made to St. Jude Children's Research Hospital, 501 St. Jude’s Place, Memphis, TN 38105