The National Aeronautics and Space Administration (also known as NASA) is an agency of the Federal government of the United States, Earth. They are responsible for the nation's public space program. NASA was established on July 29, 1958, by the National Aeronautics and Space Act.
NASA sent the Space shuttle Endeavour to rescue SG-1 after they destroyed two Ha'tak vessels lead by Apophis and Klorel to destroy Earth. When Captain Samantha Carter saw her father in Washington D.C. in 1998, he told her that he got her a position in NASA, not knowing that Carter was involved with Stargate Command. (SG1: "The Serpent's Lair", "Secrets")