NOAA-15, also known as NOAA-K before launch, is an operational, polar-orbiting of the NASA-provided Television Infrared Observation Satellite (TIROS) series of weather forecasting satellite operated by National Oceanic and Atmospheric Administration (NOAA). NOAA-15 was the latest in the Advanced TIROS-N (ATN) series. It provided support to environmental monitoring by complementing the NOAA/NESS Geostationary Operational Environmental Satellite program (GOES).

Television InfraRed Observation Satellite (TIROS) is a series of early weather satellites launched by the United States, beginning with TIROS-1 in 1960. TIROS was the first satellite that was capable of remote sensing of the Earth, enabling scientists to view the Earth from a new perspective: space. The program, promoted by Harry Wexler, proved the usefulness of satellite weather observation, at a time when military reconnaissance satellites were secretly in development or use. TIROS demonstrated at that time that "the key to genius is often simplicity". TIROS is an acronym of "Television InfraRed Observation Satellite" and is also the plural of "tiro" which means "a young soldier, a beginner".