15 Famous Astronauts Who Expanded Our Universe

Neil Armstrong is arguably the most famous astronaut of all time. As the first person to walk on the Moon during the Apollo 11 lunar landing in 1969, he delivered the iconic words: "That's one small step for man, one giant leap for mankind."

Armstrong served as the Apollo 11 mission commander and descended to the lunar surface in the lunar module. His background as a test pilot and work with the U.S. Air Force helped shape the success of early space missions.

Buzz Aldrin followed Armstrong onto the lunar surface, becoming the second person to walk on the Moon. Serving as the lunar module pilot, Aldrin had a key role in landing on the Moon.

Beyond the lunar landing, Aldrin advocated for future missions to Mars and supported space science initiatives. He helped shift the vision of the space program from near-Earth to deep-space ambitions.

Astronaut Sally Ride made history in 1983 as the first American woman in space aboard the Space Shuttle Challenger. Her journey marked a pivotal moment for women in STEM and human spaceflight.

She later participated in public outreach and served on several space policy commissions, influencing how NASA prepares for future missions.

Astronaut John Glenn became the first American to orbit Earth in 1962 aboard Friendship 7. Decades later, he flew again on the Space Shuttle Discovery in 1998, becoming the oldest astronaut in space at age 77.

Glenn's return helped scientists study how the human body responds to space travel over time.

Mae Jemison shattered barriers as the first African American woman in space during a 1992 mission aboard Space Shuttle Endeavour.

A physician and mission specialist, she conducted science experiments in orbit and has since worked to promote STEM education and support for female astronauts, especially from underrepresented backgrounds.

Alan Shepard was the first American in space, launching aboard Freedom 7 in 1961. Later, he walked on the Moon as commander of Apollo 14. His role in both early Mercury and later Apollo missions shows the evolution of NASA's space travel goals.

NASA astronaut Peggy Whitson set a NASA record with 675 days in space, the most by any American. She served on the International Space Station (ISS) across multiple expeditions and completed multiple NASA missions, acting as flight engineer, science pilot and eventually chief astronaut.

Her experience spans three NASA missions to the International Space Station and one commercial mission with Axiom Space.

Canadian astronaut Chris Hadfield brought space exploration into the digital age. Aboard the ISS, he recorded a version of David Bowie's "Space Oddity," becoming a viral sensation. As a flight engineer and commander, he also contributed to research on how microgravity affects the human body.

Valentina Tereshkova became the first woman in space in 1963 aboard Vostok 6. Her groundbreaking flight made her a symbol of Soviet space prowess and gender inclusion. She contributed to the Russian Space Federation and inspired generations of female astronauts.

Yang Liwei became the first astronaut launched by China's space program in 2003 aboard Shenzhou 5. His mission marked China's entry into human spaceflight and laid the groundwork for their current space station and lunar ambitions.

Eileen Collins was the first American woman to both pilot and command space shuttle missions. Her leadership on four space shuttle missions broke barriers and contributed to the legacy of female astronauts. Collins flew on Space Shuttle Columbia and helped test procedures for future missions.

Soviet cosmonaut Yuri Gagarin became the first human in outer space in 1961, completing one orbit of Earth in Vostok 1. His flight proved space travel was possible and ignited the Space Race between the U.S. and the Soviet Union. Gagarin remains a global icon of exploration.

Scott Kelly spent nearly a full year aboard the International Space Station in a groundbreaking mission to study the effects of long-term space travel. As a former Air Force pilot and twin brother to astronaut Mark Kelly, Scott's experience has shaped our understanding of the human body in orbit.

Koichi Wakata was the first Japanese astronaut to command the ISS. Representing the Japanese Aerospace Exploration Agency (JAXA), Wakata has flown multiple missions and contributed to international cooperation in space science.

Guion Bluford was the first African American in space, flying aboard the Space Shuttle Challenger in 1983. As an aerospace engineer and mission specialist, his contributions helped expand the diversity and expertise of NASA crews.

We created this article in conjunction with AI technology, then made sure it was fact-checked and edited by a HowStuffWorks editor.