any of a series of U.S. meteorological satellites, the first of which was launched on April 1, 1960. The TIROS satellites comprised the first worldwide weather observation system. Equipped with specially designed miniature television cameras, infrared detectors, and videotape recorders, they were able to provide global weather coverage at 24-hour intervals. The cloud-cover pictures transmitted by the TIROS craft enabled meteorologists to track, forecast, and analyze storms. From 1969, a series of advanced weather satellites known as Nimbus largely supplanted TIROS.