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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 ...
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]
Earth orbit (yellow) compared to a circle (gray) Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi), or 8.317 light-minutes, [1] in a counterclockwise direction as viewed from above the Northern Hemisphere. One complete orbit takes 365.256 days (1 sidereal year), during which time Earth has traveled 940 million ...
In 2008, more than 150 Earth observation satellites were in orbit, recording data with both passive and active sensors and acquiring more than 10 terabits of data daily. [1] By 2021, that total had grown to over 950, with the largest number of satellites operated by US-based company Planet Labs. [4]
The United States' Global Positioning System (GPS) consists of up to 32 medium Earth orbit satellites in six different orbital planes. The exact number of satellites varies as older satellites are retired and replaced. Operational since 1978 and globally available since 1994, GPS is the world's most utilized satellite navigation system.
This works out to an altitude of 35,786 km (22,236 mi). Both complete one full orbit of Earth per sidereal day (relative to the stars, not the Sun). High Earth orbit: geocentric orbits above the altitude of geosynchronous orbit (35,786 km or 22,236 mi). [8]
The prograde satellites consist of the Himalia group and three others in groups of one. The retrograde moons are grouped into the Carme, Ananke and Pasiphae groups. Saturn has 146 moons with known orbits; 66 of them have received permanent designations, and 63 have been named. Most of them are quite small. Seven moons are large enough to be in ...