Astronaut

Astronaut was a term used on Earth during the 20th and 21st centuries to designate early space explorers, primarily those from the United States of America. In particular the exploration of astronauts was limited to intrastellar missions within the Sol system. However in later centuries the term had come to have a generic meaning for any explorers in nascent space-faring societies.

Zefram Cochrane called William T. Riker, Deanna Troi, and Geordi La Forge astronauts "on some kind of star trek" after they told him the truth about his flight in the Phoenix and subsequent First Contact with the Vulcans. 

The young Jonathan Archer painted a remote controlled model spaceship model in 2121 which had two removeable astronaut figures. 

In 2151 Commander Tucker referred to the risky job astronauts did with the use of rockets: "In the old days, astronauts rode rockets with millions of liters of hydrogen burning under their seats. You think they said, "gee I'd love to go to the moon today but it seems a little risky?""

Pre-warp Earth

 * Buzz Aldrin (Apollo 11)
 * Neil Armstrong (Apollo 11)
 * Cernan (Charybdis)
 * Shaun Geoffrey Christopher (Earth-Saturn probe)
 * Zefram Cochrane (Phoenix)
 * Evans (Charybdis)
 * Fontana (Earth-Saturn probe)
 * John Glenn (Mercury 6; STS-95 on Discovery)
 * John Kelly (Ares IV)
 * Rose Kumagawa (Ares IV)
 * Andrei Novakovich (Ares IV)
 * Shannon O'Donnell (NASA-trained, never flew)
 * O'Herlihy (Earth-Saturn probe)
 * Stephen G. Richey (Charybdis)
 * Schmitt (Charybdis)
 * Alan Shepard (Freedom 7; Apollo 14)

Other pre-warp civilizations

 * Gotana-Retz (Sky ship expedition)

Background
Several real-life astronauts have appeared in Star Trek. Mae Jemison appeared as Lieutenant Palmer in the Star Trek: The Next Generation episode. She was followed by E. Michael Fincke and Terry Virts, who appeared in the final episode of Star Trek: Enterprise,.

Several places and objects in the Star Trek universe were named after, the first Human astronaut in space, including the , Yuri Gagarin Hall, Gagarin IV, the Gagarin system, and the Gagarin Radiation Belt.