The Stratospheric Observatory for Infrared Astronomy is a joint project of the German Aerospace Center (DLR) and the National Aeronautics and Space Administration (NASA). The Deutsches SOFIA Institut (DSI) at the University of Stuttgart coordinates the scientific operations on the German side. The American scientific operations are planned by the NASA Ames Research Center (ARC) and the Universities Space Research Association (USRA). Flight tests and flight operations are led by the NASA Armstrong Flight Research Center (AFRC) to the north of Los Angeles. The NASA Ames Research Center (ARC) to the south of San Francisco conducts the scientific research flights. To facilitate smooth telescope operations, the majority of DSI employees are continuously posted on site in California.