John Watts Young was an American astronaut, naval officer and aviator, test pilot, and aeronautical engineer. He became the ninth person to walk on the Moon as Commander of the Apollo 16 mission in 1972. Young enjoyed the longest career of any astronaut, becoming the first person to fly six space missions (with seven launches, counting his lunar liftoff) over the course of 42 years of active NASA service. He is the only person to have piloted, and been commander of, four different classes of spacecraft: Gemini, the Apollo Command/Service Module, the Apollo Lunar Module, and the Space Shuttle. In 1965, Young flew on the first manned Gemini mission, and commanded another Gemini mission the next year. In 1969 during Apollo 10, he became the first person to fly solo around the Moon. He drove the Lunar Roving Vehicle on the Moon's surface during Apollo 16, and is one of only three people to have flown to the Moon twice. He also commanded two Space Shuttle flights, including its first launch in 1981, and served as Chief of the Astronaut Office from 1974 to 1987. Young retired from NASA in 2004. He died on January 5, 2018.