Subject: Geoffrey Kondogbia Jersey
Author: xiaoming
Posted on: 01/14/2017 12:45:12 AM
Satellite technology has become part of all our everyday lives. From telling us what the weather is going to be like http://www.nflbearsgearofficial.com/ted-larsen-jersey/ , and how to get from one place to another, to offering us a far wider choice of programmes to watch on TV.
What is a satellite?
Satellite is a word that simply refers to one body orbiting another. There are natural satellites that orbit planets, such as our Moon, and artificial, man-made satellites that serve a variety of different purposes. The first man-made satellite, Sputnik 1, was sent into space on 4 October 1957 by the former Soviet Union. Today there are over 3,000 satellites in orbit, owned by more than 40 countries worldwide.
What are they used for?
Man-made satellites have six main uses:
- Scientific investigation
- Earth observation
- Weather
- Communications
- Navigation
- Military
What are the different types of orbit?
There are many different orbits a satellite can be put into, depending on what it's being used for. But the majority use one of the following orbits.
- Geosynchronous Earth Orbit (GEO) is where the satellite sits directly over the equator http://www.nflbearsgearofficial.com/sherrick-mcmanis-jersey/ , about 35,775 km above Earth. It will rotate in the same direction and at the same speed as our planet, so always appears to be in the same place in the sky. Communications and some weather satellites are placed in this type of orbit.
- Low Earth Orbit (LEO) is commonly described as the region between 200 and 2,000 km. Most artificial Earth satellites are placed in LEO, where they travel at about 27,000 kmh (8 kms), making one revolution in about 90 minutes. Different orbits are used for different applications, e.g. Earth observation satellites often use the Sun synchrous orbit, travelling over the Poles and thus seeing most of the Earth's surface over time, while LEO communications satellites travel in orbits centred on the equator. Some scientific missions such as Hubble look out into space from LEO.
- Medium Earth Orbit (MEO) has many definitions but is essentially the region above LEO (2 http://www.nflbearsgearofficial.com/sam-acho-jersey/ ,000 km) to 1,000 km below GEO (34,775 km). This region is used by the various Global Navigation Satellite Systems (GNSS). The European Galileo system will reside there as well as the existing US GPS and the Russian Glonass. Many other satellites pass through this region either operationally or during deployment.
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