Updated and fact-checked by the Discover Today in History editorial team.
At 10:23 a.m. Eastern Daylight Time on September 12, 1992, Space Shuttle Endeavour lifted from Launch Pad 39B at Kennedy Space Center. The mission was STS-47, an eight-day flight built around Spacelab-J, a joint program of NASA and Japan’s National Space Development Agency. Among the seven crew members was physician and engineer Mae C. Jemison. When the shuttle reached orbit, she became the first African American woman to travel in space.
The milestone is often reduced to a single sentence. The mission itself deserves more attention. Jemison flew as a science mission specialist in a laboratory operating around the clock. STS-47 carried dozens of investigations in life science and materials science and represented a deep collaboration between American and Japanese researchers. Her history-making presence and her scientific work were parts of the same story.
From medicine and engineering to NASA
Jemison was born in Decatur, Alabama, in 1956 and grew up in Chicago. She entered Stanford University at sixteen, studying chemical engineering and African and African American studies, then earned a medical degree from Cornell University. Her education resisted the false choice between science and culture that often shapes public biographies: she pursued engineering, medicine, social questions and the arts as connected forms of understanding.
After medical training, Jemison worked as a physician and served as a Peace Corps medical officer in Sierra Leone and Liberia. She later practiced medicine in Los Angeles. NASA selected her as an astronaut candidate in 1987, in the first astronaut class chosen after the loss of Challenger. Training included shuttle systems, science operations, survival skills and the technical work required of mission specialists.
Her selection was itself significant. Black Americans had contributed to the space program as mathematicians, engineers, technicians and pilots for decades, while institutional discrimination restricted access and recognition. Guion Bluford became the first African American in space in 1983. Jemison’s flight nine years later marked another barrier crossed, without erasing the longer history that made the moment possible.
A laboratory inside the shuttle
Spacelab was a pressurized laboratory carried in the shuttle’s payload bay and connected to the crew cabin by a tunnel. For STS-47, the module supported Spacelab-J, with research sponsored by NASA, NASDA and joint teams. NASA’s mission record lists 24 materials-science and 20 life-science experiments. The crew worked in red and blue teams so that investigations could continue across the orbital day.
Materials studies examined subjects including fluid behavior, electronic materials, metals, ceramics and biotechnology in microgravity. Life-science investigations used cells, plants, fungi, fruit flies, frogs and other biological systems to study how living processes change when gravity’s constant pull is largely removed.
Jemison was a co-investigator on research involving bone cells and participated in experiments related to human adaptation to spaceflight. NASA’s biographical record also identifies her work on space motion sickness, frog fertilization and bone loss. These experiments were not side activities added to a publicity flight; they were the central purpose of Spacelab-J.
September 12: launch and a first
The shuttle’s launch committed the crew to a carefully sequenced program of orbital operations. Endeavour climbed into an orbit inclined 57 degrees to the equator, allowing it to pass over a broad range of the planet. After reaching orbit, the crew configured the laboratory, divided into shift teams and began the experiment schedule.
Jemison’s place in that sequence mattered because representation changes what a society imagines to be possible. She did not enter the shuttle as a symbol alone. She entered as a trained astronaut responsible for complex research. The distinction is essential: the first African American woman in space was also a physician, engineer and mission specialist doing the work for which she had prepared.
Photographs from the mission document her inside Spacelab-J, surrounded by instrument racks, cables and experiment hardware. Those images are stronger than invented dialogue or a cinematic account of what she supposedly felt. They show the material reality of the achievement: a scientist at work in orbit.
A mission of simultaneous milestones
STS-47 also carried Mamoru Mohri, representing NASDA, on the first shuttle flight by a Japanese astronaut. Mission specialists N. Jan Davis and Mark C. Lee became the first married couple to fly together in space. The crew’s composition drew attention, but the international science program gave the flight its lasting institutional significance.
The mission completed 126 Earth orbits and traveled roughly 3.3 million miles before landing at Kennedy Space Center on September 20. Its recorded duration was 7 days, 22 hours, 30 minutes and 23 seconds. The precision of those figures contrasts with the open-ended effects of the flight: experimental results continued to be analyzed, and the people watching the mission carried its image into schools, laboratories and future careers.
After NASA—and beyond the language of “firsts”
Jemison left NASA in 1993. Her later work has crossed education, technology, public policy and entrepreneurship. She founded organizations and projects designed to encourage scientific literacy and long-range thinking, and she has repeatedly argued that science should include a wider range of people and perspectives.
Her career also challenges the way “firsts” are sometimes treated as endpoints. A first can expose exclusion, celebrate an individual achievement and widen a path, but it does not by itself create equality. Jemison’s flight became historically powerful because later students and researchers could see someone previously absent from the astronaut corps doing consequential scientific work.
Why September 12 still matters
The launch of STS-47 joined two histories. One was the technical history of the Space Shuttle and Spacelab, systems designed to place a reusable laboratory in orbit. The other was the social history of who had been allowed to represent the United States in space. On September 12, 1992, those histories met aboard Endeavour.
The enduring image is not simply of a barrier breaking at launch. It is of Jemison in the laboratory after the applause ended, checking equipment and carrying out experiments. That is what the milestone made visible: entry into space was also entry into the daily practice of science beyond Earth.
Explore the September 12 edition: return to Today in History – September 12, browse Science & Space, then continue with Ed White’s first American spacewalk, the launch of the Hubble Space Telescope, or the first view of Earth from lunar orbit.
Sources and method
Mission times, duration, experiment counts and crew details come from NASA’s official STS-47 mission record. Jemison’s education, medical service, astronaut selection and research role were checked against NASA’s Mae C. Jemison biography and image archive. Scene-setting is limited to documented launch data, spacecraft configuration and mission photography. No dialogue, private thoughts or sensory details have been invented.
