It is with deep sorrow that we announce the passing of Dr. David Alan Didion on Friday, May 15th, 2026 at his Scientists Cliffs home. Dr. Didion passed peacefully, surrounded by his family, whom he cared for deeply and was extremely proud of.  Originally from Bethel Park, Pennsylvania, and a long-time resident of the Washington DC metro area, it was love at first sight when Dave and his wife Helen first discovered the Scientists Cliffs community over 30 years ago.  An avid outdoorsman, Dave enjoyed kayaking the bay and hiking the ACLT trails.

He was an internationally recognized scientist whose specialty was heat transfer and thermodynamics. As a research Fellow at the National Institute of Standards and Technology, he and his team made significant discoveries working with industry partners that reduced ozone-depleting emissions and helped preserve the environment. Dr. Didion earned three degrees and completed postdoctoral studies at The Catholic University of America. His teaching career included the Engineering Schools at his alma mater, the University of Maryland, and Johns Hopkins University.  He will be remembered by the many aspiring engineers and researchers he inspired over the course of his 60-year career for his dry wit and compassionate mentorship.

Dave is survived and missed by his wife Helen of 67 years, his sons Jeffrey and Michael, and his daughter Mary Ellen. He will also be missed by his caring daughters-in-law, Beth and Ellen, son-in-law Perry, and 8 loving grandchildren, and two great-granddaughters.

In lieu of flowers, the family requests you consider making contributions to the American Chestnut Land Trust in remembrance of David Didion.