Concept introduction
Reconnaissance satellites are divided into photographic reconnaissance satellites, electronic reconnaissance satellites, marine surveillance satellites, early warning satellites and nuclear explosion detection satellites according to different tasks and equipment. Reconnaissance satellites have the advantages of large reconnaissance area, wide range, high speed, good effect, regular or continuous surveillance, and are not limited by national boundaries and geographical conditions. The United States, the Soviet Union/Russia and other countries have launched a large number of reconnaissance satellites.
The types of information collected can include military and non-military facilities and activities, the distribution, transportation and use of natural resources, or the acquisition of meteorological, marine and hydrological data. Because the current airspace does not include the orbital airspace around the earth, the use of satellites to collect information avoids the dispute of violating airspace; And because of the high operating height, it is not easy to be attacked.