Weather forecasts are important to everyone—in planning whether or not to carry an umbrella, when to plant crops, when to evacuate riverbank areas. Nineteenth-century American meteorologists relied on local weather observations telegraphed to the Smithsonian Institution in Washington and then plotted on a large map of the nation from which forecasts were prepared.

When Tiros-1 returned the first global cloud-cover picture in 1960, meteorologists were on their way to more accurate forecasts. Since the satellite pictures offered more comprehensive weather data over a larger geographic area, the identification of weather patterns became more reliable.

While our knowledge of atmospheric conditions is still imperfect, we have learned to make reasonably accurate regional weather forecasts and to identify and track violent storms and hurricanes based on satellite information.

The TIROS series (Television Infrared Observations Satellites) were designed to test the feasibility of weather observation from orbit. The TIROS satellite on exhibit was the prototype for the entire series of vehicles. The prototype made eight trips to the launch stand at Cape Kennedy, where it was used to check communications and handling procedures prior to the launch of the scheduled TIROS. All 10 TIROS satellites were successful. Launched between April 1, 1960, and July 1, 1965, they carried a variety of camera systems for experimental purposes.

Nine TIROS Operational Satellites (TOS) followed TIROS 1-10. Except for the first TOS, these satellites flew in pairs with one craft storing pictures on board for later transmission to major receiving centers, while the other broadcast its photographs continuously to any ground station within range. The satellite on display is of the latter type. These vehicles were launched between 1966 and 1969. They were placed in near-polar orbits by reliable Thor-Delta launch vehicles.

After launch, TOS vehicles were referred to as ESSA satellites. ESSA was an acronym both for Environmental Survey Satellite and for the Environmental Science Service Administration, the federal agency that operated the spacecraft. This organization became a part of the National Oceanic and Atmospheric Administration which currently has responsibility for operational meteorological satellite programs.

From about 1392 kilometers (865 miles) above Earth, two wide-angle television cameras mounted on either side of the spacecraft took in 10.4-million square kilometers (4-million square miles) per photo.

The Improved TIROS Operational Satellite (ITOS) opened the world of radiometric measurement to meteorologists—information about surface temperatures on the ground, at sea level, or at the cloud tops obtained by scanning devices sensitive to energy that is invisible to the naked eye. ITOS spacecraft could return accurate day or night surface and cloud-cover images. Seven of these satellites were launched between 1970 and 1973.

TIROS was presented to the National Air and Space Museum by the National Aeronautics and Space Administration; TOS is from the National Oceanic and Atmospheric Administration; ITOS is from the Astro-Electronics Division of RCA, Inc.