Douglas Kleinmann, a Ridgefield, CT resident, passed away on July 13, 2025, at the age of 83, a gentle, quiet soul, a loving husband, father, grandfather, uncle, grandfather, scientist, and manager.

Born in Chicago on July 11, 1942, to Erwin Kleinmann and Ruth Kleinmann (nee Stone), Doug was the eldest of four brothers, an eagle scout, a band member (trumpet), and class valedictorian at Sunset High School in Dallas. He went on to earn a BS in Physics at Rice University, and an MS and PhD in Rice's new Space Science Department, opened only 2 years after President Kennedy announced the mission to land a man on the Moon.

For decades afterwards, he used new technology for research in astrophysics.  He discovered a massive cloud of cold gas and dust (the "Kleinmann-Low Nebula") in the constellation Orion, where thousands of new stars began shining only in the last hundred thousand years.  This discovery led to a revolution in our understanding of how the gas in space forms molecules, clouds, stars and planets.  For this work, Doug was inducted into The Explorers Club in New York.

Later in his career, Doug obtained an MBA from MIT's Sloan School of Management, and began working on space-based projects that looked down at the Earth rather than up from it.  As a program manager at Honeywell, he led the delivery of a new class of imaging devices designed to measure ozone in the upper atmosphere, and were eventually flown on the Space Shuttle.  He then led the delivery of imaging components for a new class of satellite-born cameras that (to this day) look down on the Earth to measure many aspects of the atmosphere.

As a life-long scout, he was a committee member and later chairman of Boy Scouts of America, Troop 119, in Lexington, MA.

Doug was known for his even temper, straightforwardness, reliability, and love of exploration. He faced his final years with grace, battling cancer, Parkinson's disease, and a traumatic injury with dignity.

He is survived by his beloved wife Susan, his son Peter, and grandson Oliver, his brothers Ken, and Kurt.