The National Aeronautics and Space Administration (NASA) is an American government agency which runs the civilian arm of the space program. The aim of NASA is to increase human understanding of the solar system and the universe that contains it, and to improve American aeronautics ability. Under its charter, NASA is supposed to be a peacetime agency that does not perform military functions, although NASA does cooperate with the military, and many NASA employees have a military background. To achieve this goal, NASA has an annual budget which can be counted in the billions to fund programs and pay tens of thousands of employees.

NASA was founded in 1958, in response to the Soviet launch of Sputnik in 1957. The early years of the organization were driven by Cold War competitiveness, and NASA quickly worked on creating rockets which would allow for manned spaceflight. NASA astronauts Neil Armstrong and Buzz Aldrin were the first humans known to have set foot on the moon in 1969, an action that was considered a major victory for American aeronautics. Riding on this early success, NASA continued development of aeronautic equipment designed to function outside the Earth's atmosphere.

After the moon landing, NASA focused on doing research around the solar system, sending an assortment of manned flights to the moon to collect material for study, and unmanned drones to other planets to collect data. These flights have collected large amounts of data which are constantly being added to and analyzed. Scientific advancement is a large part of NASA's mission. With the assistance of the agency, scientists have been able to conduct experiments in the zero gravity environment of space, and test hypotheses about the universe.

NASA also continues to work on a space shuttle program to make space more accessible. As of 2007, the space shuttle had made 112 flights with astronauts from many nations including the United States, and two of these flights, the Challenger and Columbia, were lost. NASA plans to resume manned flights to the moon by 2020, after safety improvements have been made to the space shuttle.

As part of its mission as a peaceful agency, NASA cooperates with agencies within the United States and international aeronautics agencies. A NASA astronaut can usually be found on board the International Space Station, and astronauts from other nations are invited to participate in NASA events. This fostering of international cooperation will hopefully continue as humans explore space and the possibility of off-Earth human settlements becomes possible.