Charles Momsen, American admiral, invented the Momsen lung (died 1967)

Charles Bowers Momsen, nicknamed "Swede", was born in Flushing, New York. He was an American pioneer in submarine rescue for the United States Navy, and he invented the underwater escape device later called the "Momsen lung", for which he received the Navy Distinguished Service Medal in 1929. In May 1939, Momsen directed the rescue of the crew of Squalus (SS-192).

The Momsen lung was a primitive underwater rebreather used before and during World War II by American submariners as emergency escape gear. It was invented by Charles Momsen, who worked on it from 1929 to 1932. Submariners trained with this apparatus in an 80 ft (24 m) deep Escape Training Tank at New London, Mare Island, or Pearl Harbor. It was introduced as standard equipment on Porpoise (P)-class and Salmon-class boats.

June 21 is the 172nd day of the year in the Gregorian calendar; 193 days remain until the end of the year.