Astronaut Buzz Aldrin was one of the first people to walk on the moon. He and flight commander Neil Armstrong made the Apollo 11 moonwalk in 1969.

African-American physicist and astronaut Ronald McNair was one of the seven crew members killed in the 1986 Space Shuttle 'Challenger' explosion.

As a mission specialist aboard the space shuttle 'Challenger' in 1983, Guion S. Bluford became the first African American to travel into space.

Mae C. Jemison is the first African American female astronaut. In 1992, she flew into space aboard the Endeavour, becoming the first African American woman in space.

High school teacher Christa McAuliffe was the first American civilian selected to go into space. She died in the explosion of the space shuttle 'Challenger' in 1986.

In 1983, astronaut and astrophysicist Sally Ride became the first American woman in space aboard the space shuttle Challenger. Ride died on July 23, 2012 at the age of 61, following a battle with pancreatic cancer.

Astronaut, military pilot, and educator, Neil Armstrong made history on July 20, 1969, by becoming the first man to walk on the moon.

In 1963, cosmonaut Valentina Tereshkova became the first woman to travel in space aboard Vostok 6.

Jim Lovell is a former NASA astronaut and retired U.S. Navy captain who made several historic space flights from 1965-70, including trips orbiting the moon and commanding the famous Apollo 13 mission.

John Glenn was the first U.S. astronaut to orbit Earth, completing three orbits in 1962. He also served as a U.S senator from Ohio.

Alan Shepard became one of the original seven Mercury program astronauts in 1959. He later commanded the Apollo 14 flight.

Chris Hadfield is a pioneering Canadian astronaut who became a global celebrity through his Twitter feed while aboard the International Space Station in 2013.

Selected by NASA in 1990, Ellen Ochoa became the world's first Hispanic female astronaut in 1991.

Michael Collins is a former astronaut who was part of the Gemini 10 and Apollo 11 missions, the latter of which included the first lunar landing in history.