Clifton Williams, American astronaut (b. 1932)
Clifton Curtis "C.C." Williams, Jr. (September 26, 1932 – October 5, 1967), (Major, USMC), was an American naval aviator, test pilot, mechanical engineer, major in the United States Marine Corps, and NASA astronaut, who was killed in a plane crash; he never went into space. The crash was caused by a mechanical failure in a NASA T-38 jet trainer, which he was piloting to visit his parents in Mobile, Alabama. The failure caused the flight controls to stop responding, and although he activated the ejection seat, it did not save him. He was the fourth astronaut from NASA's Astronaut Group 3 to have died, the first two (Charles Bassett and Theodore Freeman) having been killed in separate T-38 flights, and the third (Roger B. Chaffee) in the Apollo 1 fire earlier that year. The aircraft crashed in Florida near Tallahassee within an hour of departing Patrick AFB.

Before becoming an astronaut, Williams received his Bachelor of Science degree in Mechanical Engineering from the Auburn University in 1954 and joined the U.S. Marine Corps through the Naval Reserve Officers Training Corps (NROTC). He became a Naval Aviator in 1956 and joined the Fleet Marine Force. In 1960, he graduated from the U.S. Naval Test Pilot School. As a test pilot, he worked for three years in the Carrier Suitability Branch of the Flight Test Division at NAS Patuxent River. In 1962, Williams, then a Captain, became the first pilot to land a two-seat jet on the aircraft carrier from the rear cockpit. At the time of his death, he was 35 and held the rank of Major.

Although he was never on a spaceflight, he served as backup pilot for the mission Gemini 10, which took place in July 1966. Following this mission, he was selected to be the Lunar Module Pilot for an Apollo mission to the Moon commanded by Pete Conrad. Following Williams' death, Alan Bean became Lunar Module Pilot for Conrad's mission, which ended up being Apollo 12, the second lunar landing. In his honor—on Bean's suggestion—the mission patch had four stars instead of three; one for each of three astronauts and one for Williams. Also, Bean placed Williams' naval aviator wings and silver astronaut pin to rest on the lunar surface during his moonwalk.