NASA stands for The National Aeronautics and Space Administration. It is a government agency that is responsible for the civilian space program as well as for aeronautics and aerospace research in the United States of America(USA). It was formed on July 29, 1958. Its Headquarters is in Washington, D.C.
More phrases which can be derived from NASA are National Auto Sport Association, National Aggregate Stone Association, Negotiating Agents Steering API etc. Some funny full form include National Acronym Slinging Agency, Never Absolutely Sure of Anything etc.