Earth observation - A short historical account
The modern space age started in October 1957 when a small metal sphere with long antennas was launched into space.
This Soviet Sputnik-1, weighing 83 kg, was the world's first artificial satellite. |
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| Satellites with both optic and radar instruments |
| The world's most advanced environmental satellite, Envisat, was launched the night before 1st March. |
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| Satellites with optical sensors |
| Sputnik-1 was a simple satellite. It consisted of a metal sphere half a meter high, which contained a radio transmitter, and also four radio antennas. |
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| Radar satellites |
| Instruments on board in radar satellites transmit radar beams towards the surface of the Earth. The first satellite of this type, Seasat, was developed in the USA by NASA. |
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