NASA

The Space Shuttle program launched on April 12th, 1981, was the fourth crewed program in NASA's history.

An excerpt from the article 29 facts about NASA
It launched a total of 135 missions and was the first program to reuse a spacecraft. Its main goal was the transportation of crew and cargo from Earth to orbit. Throughout the span of 30 years, it carried 355 astronauts from 16 countries.