Guion Stewart Bluford Jr. (born November 22, 1942) is an American aerospace engineer, retired United States Air Force (USAF) officer and fighter pilot, and former NASA astronaut in which capacity he became the second person of African descent to go to space. While assigned to NASA, he remained a USAF officer rising to the rank of colonel. He participated in four Space Shuttle flights between 1983 and 1992. In 1983, as a member of the crew of the Orbiter Challenger on the mission STS-8, he became the first African American in space as well as the second person of African descent in space, after Cuban cosmonaut Arnaldo Tamayo Méndez.