Guion (Guy) Bluford, Jr., the first African-American in space, joined NASA as an astronaut in August 1979. He has logged over 688 hours in space on four flights as mission specialist: STS-8 (Challenger); STS-61-A (Challenger); STS-39 (Discovery), and; STS-53 (Discovery).
Ronald McNair became an astronaut in 1978 and flew on mission STS-41-B aboard Challenger in 1984, the second African-American in space. His second mission was STS-51-L also on the Challenger which exploded just 73 seconds after lift-off. He was posthumously awarded the Congressional Space Medal of Honor in 2004 along with the crews of the Challenger and Columbia accidents.
Mae Jemison, the first African-American female in space, flew one mission on STS-47 (Endeavor) as mission specialist in 1992. She left NASA the following year and is a Professor-at-Large at Cornell University.