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Earth observation satellite missions developed by the ESA as of 2019. Earth observation satellites are Earth-orbiting spacecraft with sensors used to collect imagery and measurements of the surface of the earth. These satellites are used to monitor short-term weather, long-term climate change, natural disasters.
Samples of three GPS satellites' orbits over a five-year period (2013 to 2018) USA-242 · USA-239 · USA-151 · Earth As of 15 August 2023, 83 Global Positioning System navigation satellites have been built: 31 are launched and operational, 4 are unhealthy or in reserve, 41 are retired, 2 were lost during launch, and 1 prototype was never launched. 4 Block III satellites have completed ...
The first artificial satellite launched into the Earth's orbit was the Soviet Union's Sputnik 1, on October 4, 1957. As of December 31, 2022, there are 6,718 operational satellites in the Earth's orbit, of which 4,529 belong to the United States (3,996 commercial), 590 belong to China, 174 belong to Russia, and 1,425 belong to other nations. [1]
Earth also has more than 20 known co-orbitals, including the asteroids 3753 Cruithne and 469219 Kamoʻoalewa, and the occasional temporary satellite, like 2020 CD 3; however, since they do not permanently orbit Earth, they are not considered moons. (See Other moons of Earth and Quasi-satellite.)
A satellite in a geostationary orbit appears stationary, always at the same point in the sky, to ground observers. Popularly or loosely, the term "geosynchronous" may be used to mean geostationary. [1] Specifically, geosynchronous Earth orbit (GEO) may be a synonym for geosynchronous equatorial orbit, [2] or geostationary Earth orbit. [3]
One complete orbit takes 365.256 days (1 sidereal year), during which time Earth has traveled 940 million km (584 million mi). [2] Ignoring the influence of other Solar System bodies, Earth's orbit, also called Earth's revolution, is an ellipse with the Earth–Sun barycenter as one focus with a current eccentricity of 0.0167. Since this value ...
Orbiting more than 300 miles above Earth, the satellites can be seen without special equipment. ... Starlink is the first and largest satellite constellation in low Earth orbit, ... The Today Show.
Geocentric orbit: An orbit around the planet Earth, such as that of the Moon or of artificial satellites. Selenocentric orbit (named after Selene ): An orbit around Earth's Moon. Areocentric orbit (named after Ares ): An orbit around the planet Mars, such as that of its moons or artificial satellites. For orbits centered about planets other ...