A retired United States Air Force (USAF) colonel, aeronautical engineer, test pilot, businessman, rancher, and NASA astronaut. He was the commander of Apollo 8, the first mission to fly around the Moon, and together with crewmates Jim Lovell and Bill Anders, became the first of 24 humans to do so, for which he was awarded the Congressional Space Medal of Honor. As of 2021, he is the oldest living former American astronaut, eleven days older than Lovell.