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.
The term refers to both the individual and to the position on the Shuttle crew.
The National Aeronautics and Space Act of 1958 states that NASA should provide the "widest practicable and appropriate dissemination of information concerning its activities and the results thereof". The Naugle panel of 1982 concluded that carrying civilians—those not part of the NASA Astronaut Corps—on the Space Shuttle was part of "the purpose of adding to the public's understanding of space flight".
Payload specialists usually fly for a single specific mission. Chosen outside the standard NASA mission specialist selection process, they are exempt from certain NASA requirements such as colorblindness. Roger Crouch and Ulf Merbold are examples of those who flew in space despite not meeting NASA physical requirements;: 63 the agency's director of crew training Jim Bilodeau said in April 1981 "we'll be able to take everybody but the walking wounded". Payload specialists were not required to be United States citizens, but had to be approved by NASA and undergo rigorous but shorter training. In contrast, a Space Shuttle mission specialist was selected as a NASA astronaut first and then assigned to a mission.
Payload specialists on early missions were technical experts to join specific payloads such as a commercial or scientific satellite. On Spacelab and other missions with science components, payload specialists were scientists with expertise in specific experiments. The term also applied to representatives from partner nations who were given the opportunity of a first flight on board of the Space Shuttle (such as Saudi Arabia and Mexico), to Congressmen and the Teacher in Space program. Under Secretary of the Air Force Edward C. Aldridge, Jr. was offered a seat to improve relations between NASA and the United States Air Force.
NASA categorized full-time international astronauts as payload specialists unless they received NASA mission specialist training, which some did.: 63 Bilodeau estimated that payload specialists would receive a couple of hundred hours of training over four or five weeks. International or scientific payload specialists were generally assigned a back-up who trained alongside the primary payload specialist and would replace him/her in the event of illness or other disability. Both primary and backup payload specialists received mission-specific and general training. Michael Lampton estimated that about 20% of his training was general, including firefighter school, capsule communicator duty, and use of Personal Egress Air Packs and the space toilet. He described training for Spacelab 1 as "going back to graduate school but majoring in everything"; as the first mission it tested Spacelab's versatility in "medical, metallurgical, remote sensing, astronomy, microgravity, lots more".: 59–60
Payload specialists operated experiments, and participated in experiments needing human subjects. Charles D. Walker recalled that Senator Jake Garn "and I were the obvious subjects" for Rhea Seddon's echocardiograph on STS-51-D. "We really didn’t have much of a choice in whether we were going to be subjects or not. 'You're a payload specialist; you’re going to be a subject.'" Besides his own electrophoresis work, Walker operated an unrelated experiment for the University of Alabama Birmingham, and helped build homemade repair tools for a satellite launched on the mission.
Payload specialists were flown from 1983 (STS-9) to 2003 (STS-107). The last flown payload specialist was the first Israeli astronaut, Ilan Ramon, who was killed in the Columbia disaster on mission STS-107 with the rest of the crew.
Within NASA, Johnson Space Center (JSC) controlled manned spaceflight by selecting professional, full-time astronauts. The payload specialist program gave Marshall Space Flight Center (MSFC)—which supervised Spacelab, including a contracted European Space Agency-chosen payload specialist—control as well, causing conflicts. JSC director Chris Kraft and members of the NASA astronaut corps believed that mission specialists—many with doctoral degrees or other scientific background, and all with full-time astronaut training—could operate all experiments. Rick Chappell, chief scientist of MSFC, believed that the scientific community insisted on its own scientists being able to operate experiments in exchange for support of the Space Shuttle program. While mission specialists could operate most experiments, "Since we could take passengers, why not take at least a couple of passengers who had spent their whole careers doing the kind of research they were going to do in space?" he said.: 9–10, 15, 18, 28–29, 48
During the Space Shuttle design process, some said that crews should be no larger than four people; both for safety, and because a commander, pilot, mission specialist, and payload specialist were sufficient for any mission. NASA expected to fly more payload specialists so designed a larger vehicle. Only NASA astronauts piloted the space shuttle, but mission specialist astronauts worried about competing with American and international payload specialists for very limited flight opportunities. In 1984 about 45 mission specialists competed for about 15 seats on the five shuttle flights. Only three payload specialists flew that year, but in 1985 eight of nine shuttle flights carried 15 payload specialists (Walker flying twice), no doubt angering mission specialists. Some payload specialists like Walker and Byron Lichtenberg were rejected as full-time astronauts but flew as payload specialists before many selected as such, and some may have flown without understanding the level of danger. Many astronauts worried that without years of training together they would not be able to trust payload specialists in an emergency; Henry Hartsfield described their concern as "If you had a problem on orbit, am I going to have to babysit this person?" NASA's preference for its own training caused the agency to offer some international payload specialists the opportunity to become mission specialists, the first being Claude Nicollier.: 40–44, 48–50, 61–63
Those skeptical of the payload specialist program were less critical of scientists and experts like Walker than non-expert passengers ("part-timers", according to Mike Mullane, who called the program public relations-driven and immoral in Riding Rockets) like Garn, US Representative Bill Nelson, and other civilians such as Teacher in Space Christa McAuliffe. They saw Senator John Glenn as a passenger despite being a former Mercury Seven astronaut.: 40, 51  A 1986 post-Challenger article in The Washington Post reviewed the issue, reporting that as far back as 1982, NASA was concerned with finding reasonable justifications for flying civilians on the Shuttle as was directed by the Reagan administration. The article says that "A review of records and interviews with past and present NASA and government officials shows the civilian program's controversial background, with different groups pushing for different approaches". The article concludes with:
Author Tom Wolfe, who chronicled the early days of the space program in The Right Stuff, wrote after the Challenger explosion that support for the citizen program, and therefore McAuliffe's place aboard the ill-fated shuttle, was part of an insiders' battle. NASA civilians, pitting themselves against the professional astronauts, used the program for the "dismantling of Astropower," which Wolfe described as "the political grip the original breed of fighter-pilot test-pilot astronauts had on NASA."
Payload specialists were aware of full-time astronauts' dislike of the program. Garn advised STS-51-D colleague Jeffrey A. Hoffman to not play poker because, the astronaut quoted, "'It took you a while to disguise your initial skepticism about this whole thing'". Merbold said that at JSC he was treated as an intruder. Once payload specialists were assigned to a mission, however, full-time astronauts treated them respectfully and often began long-term friendships. Mullane became less critical of them after his first mission; he and Hartsfield approved of Walker, as did Hoffman of Garn after STS-51-D.: 40, 48, 50–52
List of all payload specialists
|Ulf Merbold||STS-9||first payload specialists, Ulf Merbold was the first international (German) payload specialist|
|Byron K. Lichtenberg|
|Charles D. Walker||STS-41-D||first non government-affiliated payload specialist|
|Marc Garneau||STS-41-G||Garneau was the first Canadian in space, Scully-Power the first Australian|
|Gary Payton||STS-51-C||first military payload specialist|
|Charles D. Walker||STS-51-D|
|Jake Garn||then-U.S. Senator, first U.S. legislative branch payload specialist|
|Lodewijk van den Berg||STS-51-B|
|Patrick Baudry||STS-51-G||two international payload specialists|
|Sultan bin Salman Al Saud|
|John-David F. Bartoe|
|William A. Pailes||STS-51-J|
|Reinhard Furrer||STS-61-A||three international payload specialists, most payload specialists on a single flight|
|Rodolfo Neri Vela||STS-61-B||first Mexican in space|
|Charles D. Walker||Walker's third and final spaceflight|
|Robert J. Cenker||STS-61-C|
|Bill Nelson||then-U.S. Representative, second and final U.S. legislative branch payload specialist|
|Gregory Jarvis||STS-51-L||killed in the Challenger disaster|
Post-Challenger to Columbia
Alternate and back-up (not flown) payload specialists
|Wubbo Ockels||STS-9||flew on STS-61-A|
|Robert Thirsk||STS-41-G||flew on STS-78|
|Robert E. Stevenson|
|Eugene H. Trinh||flew on STS-50|
|Jean-Loup Chrétien||STS-51-G||flew on STS-86 as a mission specialist|
|George W. Simon||STS-51-F|
|Diane K. Prinz|
|Ulf Merbold||STS-61-A||flew on STS-9, STS-42|
|Barbara Morgan||STS-51-L||flew on STS-118 as a mission specialist|
|Robert W. Phillips||STS-40|
|Charles R. Chappell|
|Joseph M. Prahl||STS-50|
|Albert Sacco||flew on STS-73|
|Jean-Jacques Favier||STS-65||flew on STS-78|
|David H. Matthiesen||STS-73|
|R. Glynn Holt|
|Pedro Duque||STS-78||flew on STS-95 as a mission specialist|
|Alexander W. Dunlap||STS-90|
|Chiaki Mukai||flew on STS-65, STS-95|
|2||Ulf Merbold, Byron K. Lichtenberg, Samuel T. Durrance, Ronald A. Parise, Chiaki Mukai, Roger Crouch, Greg Linteris|
|No. of payload specialists flights||Country|
|Total||60 payload specialist flight opportunities|
Payload specialists who trained later as mission specialists
All were international astronauts.
- Marc Garneau – flew on STS-77, STS-97
- Mamoru Mohri – flew on STS-99
- Steven MacLean – flew on STS-115
- Hans Schlegel – flew on STS-122
- Umberto Guidoni – flew on STS-100
- Robert Thirsk – flew on Soyuz TMA-15
- Bjarni Tryggvason – retired in June 2008 without flying again
- Pincus, Walter (1986-03-05). "NASA's Push to Put Citizen in Space Overtook Fully 'Operational' Shuttle". Washington Post. ISSN 0190-8286. Retrieved 2020-07-14.
- Collins, Debbie. "The Power of Persistence". NASA. Retrieved 2020-06-21.
- Croft, Melvin; Youskauskas, John (2019). Come Fly with Us: NASA's Payload Specialist Program. Outward Odyssey: a People's History of Spaceflight. University of Nebraska Press. ISBN 9781496212252.
- Stevens, William K.; Times, Special To the New York (1981-04-06). "New Generation of Astronauts Poised for Shuttle Era". The New York Times. p. A1. ISSN 0362-4331. Retrieved 2020-07-14.
- Walker, Charles D. (14 April 2005). "Oral History Transcript". NASA Johnson Space Center Oral History Project (Interview). Interviewed by Johnson, Sandra.
- Oberg, James. "NASA hypes "Glenn Mission" Science". jamesoberg.com. Retrieved 4 March 2017.
- Ramsay, Janis (21 February 2015). "Barrie astronaut continues to keep eye on skies". Barrie Advance. Retrieved 10 January 2019.