A "payload specialist" is a person onboard a spacecraft whose main job is to take care of and operate the scientific, technological, or research equipment that the spacecraft is carrying. Full definition
1998 — Dr. Alexander Dunlap (LSU SVM 1989) was alternate payload specialist and ground veterinarian for the STS - 90 Neurolab space shuttle mission flown. (lsu.edu)
Payload specialist and space station engineer Ravi Margasahayam told Business Insider that each pound of cargo used to cost $ 10,000 to ship into space. (businessinsider.com)
Thirsk visited the void twice, including 17 days as a payload specialist aboard the space shuttle Columbia in 1996, and six months aboard the International Space Station last year. (canadianbusiness.com)