Donald Howard Menzel
A prominent scientist and noted skeptic, Menzel has debunked many UFO cases as prosaic phenomena such as clouds, meteors and military airplanes and rockets.
Menzel served as a lieutenant commander in the United States Navy in World War II, climbed the ranks, and headed a division of naval intelligence in 1944. After the war he continued to work for the Navy while he worked to improve radio-wave propagation. He was appointed as director to the Harvard Observatory in the 1950's and before later serving as a U.S. State Department consultant for Latin American affairs.
In the 1950's Menzel was commissioned by the Psychological Strategy Board to provide a skeptical view on the UFO phenomena. He co-authored several books on UFOs, as he explained sightings and incidents with prosaic explanations, misidentifications or hoaxes. Menzel claimed he witnessed an unidentified flying object in 1955 but stated that the 'flying saucer' he observed was a mirage of Sirius, a bright star.
In 1968, Menzel testified in front of the "U.S. House Committee on Science and Astronautics – Symposium on UFOs", and claimed that he considered all UFO sightings to have natural explanations.