NASA stands for the National Aeronautics and Space Administration. It is the United States government agency responsible for the nation’s civilian space program as well as aeronautics and aerospace research. Founded on July 29, 1958, in response to the Soviet Union's advancements in space technology, NASA has since played a crucial role in numerous space explorations, including the Apollo moon-landing missions, the Space Shuttle program, and the Mars rover expeditions. NASA continues to engage in scientific research, technology development, and international collaborations to advance our understanding of Earth and beyond.