Types of Satellites

- Types of Satellites

In most cases, satellites are placed in one of several predetermined orbits around the Earth after launch. But in some cases, it might be guided on interstellar travel, following a path around the sun until it reaches its final destination.

Satellites are usually classified according to their orbital altitude (distance from the Earth's surface), which directly affects their coverage area and the speed at which they travel around the Earth. When choosing an orbit type, spacecraft developers should consider its intended use, data acquired and services provided, as well as the cost, coverage, and feasibility of different orbits. The 5 main satellite types based on orbit are:

• Low Earth Orbit (LEO): Low Earth Orbit (LEO), with an orbital period of 128 minutes or less and an altitude of less than 2,000 kilometers. Primarily used for communications and remote sensing satellites; the International Space Station and the Hubble Space Telescope are in low Earth orbit. 
• Medium Earth Orbit (MEO): Medium Earth Orbit (MEO), orbital period less than 24 hours but greater than 128 minutes, altitude between 2000 km and 35786 km. Mainly used for navigation and timing satellites; GPS and Glonass in MEO. 
• Geosynchronous Orbit (GSO): Geosynchronous Orbit (GSO), orbital period equal to the Earth's rotation period, fixed longitude position altitude 35,786 km. Mainly used for communication and earth sensing satellites; traditional space-based Internet satellites and communication satellites are in GSO. 
• Sun-synchronous orbit (SSO) is a particular kind of polar orbit. Satellites in SSO, travelling over the polar regions, are synchronous with the Sun. This means they are synchronised to always be in the same 'fixed' position relative to the Sun.
• Geostationary Orbit (GEO): Geostationary Orbit (GEO) is a form of GSO in which satellites orbit the Earth's equator exclusively, appearing stationary to Earth observers. Mainly used for communication and earth sensing satellites; satellite TV and weather satellites are in GEO.

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