Since the world’s first satellite, the Sputnik 1, was launched by the Soviet Union in 1957, thousands of satellites have been launched into orbits around the Earth and other planets for a number of purposes. Common types include military and civilian Earth-observation satellites, communications satellites, navigation satellites, weather satellites, and science satellites.
By observing the Earth from space, satellites provide essential information about land environments, the ocean, ice, and the atmosphere. Earth-observation satellites help monitor and protect the environment, manage resources, and ensure the safety and security of human beings. Satellite imagery is also used to support global humanitarian efforts and sustainable development.
Communications satellites are the most-economical way to connect even the most-remote communities of the world with the advanced services needed to compete in the global knowledge economy. These satellites also assist search-and-rescue teams, provide ships, aircraft, and ground vehicles with geopositioning information, and beam instructors to classrooms across the country.
Navigational satellites enable mobile receivers on the ground to determine their exact location using radio time signals. The relatively clear line of sight between the satellites and receivers on the ground allows satellite navigation systems to measure location with accuracy on the order of a few meters in real time.
Weather satellites are primarily used to monitor the weather and climate of the Earth. These meteorological satellites also see fires, effects of pollution, auroras, sand and dust storms, snow cover, ice mapping, boundaries of ocean currents, energy flows, and other types of environmental information. Weather satellite images also help monitor the volcanic ash.
Scientific satellites and spacecraft study the physics and effects of phenomena of the Earth and other planetary bodies, such as aurora borealis on Earth’s magnetic field. These satellites expand our understanding of the origin, formation, structure, and evolution of celestial bodies and the universe.
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