A Mission Specialist is assigned to a limited field of the mission, such as for medical experiments or technical quests. Other functions on board are Pilot, Flight Engineer and Mission Commander. Some Space Shuttle missions included Payload Specialists in addition to Mission Specialists. While a Payload Specialist was selected for a single specific mission, a Mission Specialist was selected as an astronaut first, and then assigned to a mission. Mission Specialist is abbreviated by NASA as MS.
- A person wishing to be a Mission Specialist must pass a NASA Class II space physical to be certified for flight.
- A bachelor's degree in engineering, biological science, physical science or mathematics, as well as at least three years of related professional experience (graduate work or studies) and an advanced degree, such as a master's degree (one to three years) or a doctoral degree (three years or more).
- Applicant's height must be between 4 ft. 10.5 in. and 6 ft. 4 in.
- It is possible that Dr. Ryan Stone should have been a Payload Specialist as opposed to a Mission Specialist. This can't be considered an inaccuracy because she could have also been a Mission Specialist. Either way is possible. A Payload Specialist (PS) is 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.