The mathematics of putting an artificial satellite into orbit were known for a long time before the feat was finally accomplished with the launch of Sputnik I in 1957. And meteorologists had long realised the benefits such an achievement would have for the more accurate prediction of weather.
Not surprisingly, therefore, only three years after Sputnik a satellite dedicated to the weather was launched in April 1960. The American TIROS I, for Television and Infra-Red Observations Satellite, transmitted 20,000 pictures over its two-year lifetime and has had dozens of successors.
But weather people had another dream. Again long before the launch of Sputnik I, Arthur C Clarke, better known, perhaps, for his popular science fiction, suggested the concept of a "geostationary orbit", one in which the satellite is positioned over the equator in such a way that its speed in orbit matches the speed at which the Earth rotates on its axis underneath.
Clarke first explained his notion in a memorandum prepared for the British Interplanetary Society in May 1945, seeing it primarily as a means of providing worldwide UHF communications. He suggested using "a chain of space stations with an orbital period of 24 hours".
"The stations would lie in the Earth's equatorial plane, and would thus always remain fixed in the same spots in the sky from the point of view of terrestrial observers. Unlike other heavenly bodies, they would never rise or set. This would greatly simplify the use of directive receivers installed on the Earth."
For weather people the idea also opened up exiting possibilities. A geostationary satellite could provide successive pictures of the same field of view, taken at, say, half-hourly intervals, which could be combined to form a "movie" of the evolving weather situation below.
This ambition was realised just 35 years ago today when the first meteorological geostationary satellite went into orbit on December 6th, 1966. It was called ATS-1, the initials this time standing for Applications Technology Satellite, and was positioned at 151 degrees west longitude, over the equator and the centre of the Pacific Ocean.
ATS-1 was the first of a constellation of five weather satellites, dotted like well-spaced beads on an invisible celestial necklace high above the equator. The successors of these five still provide us with pictures of the global weather and a great deal more information about the atmosphere.