A payload specialist (PS) was an individual selected and trained by commercial or research organizations for flights of a specific payload on a NASA Space Shuttle mission. People assigned as payload specialists included individuals selected by the research community, a company or consortium flying a commercial payload aboard the spacecraft, and non-NASA astronauts designated by international partners.
Ukrainian astronaut Leonid Kadenyuk seen with a badge of payload specialist on the left side of his chest
The NASA Astronaut Corps is a unit of the United States National Aeronautics and Space Administration (NASA) that selects, trains, and provides astronauts as crew members for U.S. and international space missions. It is based at Johnson Space Center in Houston, Texas.
NASA space suits previously worn by the Astronaut Corps at the Johnson Space Center (center, Pete Conrad's suit worn during the 1969 Apollo 12 mission)