[Illustration: 35. TOS satellite is covered with solar cells.]
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.
[Illustration: 36. _TIROS I_ photo showing a section of the East
coast of the United States, including the Boston and New England
area.]
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.
[Illustration: 37. Artist’s concept of ITOS weather satellite
illustrating how the weather eye takes night-time (infrared)
cloud-cover pictures.]