The Moon is Earth’s only natural Satellite and its closest neighbour in space, the rest are all man-made Satellites.
Natural Satellites are things like moons and rings. These are held in place by a planet’s gravity and so are stuck in orbit.
There are currently about 1,800 active man-made Satellites orbiting the Earth right now, plus there are about 2,900 more that no longer work.
Russia launched the first ever satellite in 1957 called, Sputnik 1. It only lasted three months in orbit before finally burning up in the Earth’s atmosphere.
The Satellites are either privately owned or owned by a countries government.
Most Satellites are launched into orbit by rocket, but some are taken into space in the payload bay of a space shuttle. Once the satellite has separated from the launcher, an on board motor propels it into its correct orbit.
The Satellites orbiting Earth work for us in a variety of ways. The most important are the telecommunication Satellites that effect most of our lives. They give us global communication at the touch of a button, beams television pictures right into our living rooms, and are used in all type of business, day and night.
Satellites are essential to our daily lives for example, checking the weather, travelling, and even using the internet. Look on a roof and you will see a Satellite dish, this device receives signals from Satellites in space, which enables you to watch events live from the opposite side of the world.
The Hubble Space Telescope is an imaging Satellite that studies distant galaxies in outer space.
The Earth,s weather is monitored by weather Satellites. These study the clouds, tracking both their size and temperature. They can predict when storms or hurricanes might occur enabling people to evacuate dangerous areas.
The Global Positioning Service is a system of Satellites owned by the American government. It can track locations of devices like mobile phones on Earth. It makes it relatively easy for us to find our way around. Applications like Google Maps use GPS system.
The largest Satellite is the International Space Station, which was put together by several different countries.
Satellites vary in size, one can be the size of a shoe-box, while a big one could be as big as a double-decker bus.
Aircraft pilots, yachtsmen, soldiers and now hikers navigate their way about Earth using Satellites. The Global Positioning System (GPS), uses a set of 24 satellites in orbit around Earth. The user sends a signal from a hand set, which is received by up to 12 of the Satellites. By return, he learns his location, direction and speed.
There are four types of Satellites. The GEO (GEOSTATIONARY EARTH ORBIT), LEO (LOW EARTH ORBIT), MEO (MEDIUM EARTH ORBIT) and the HEO (HIGHLY ELLIPTICAL ORBIT).
The distance from Earth to the Satellites varies between 1,243 miles to 22,223 miles.
The first live television pictures were transmitted in 1962 by the Telstar Satellite. In the years that followed, live television became more popular. By 1987, Roman Catholics on five different continents around the world, could watch Pope John Paul II in a live broadcast using 23 Satellites.
Satellites are built to work in space for long periods. But all eventually stop working and their roles are taken over by new ones. It takes only one part of a Satellite to malfunction and the Satellite is dead.
A Satellite is subject to large temperature changes in space. As it orbits the Earth it moves regularly between brilliant sunshine and black space. It is subject to severe temperature differences, because as one side of it is getting sun baked, the opposite side of it is tens of degrees below freezing.
Satellites are shielded from temperature extremes by metal coated blankets, which prevents warping, bending and equipment failure.
It is estimated the cost of a Satellite launch can range from $50 million to $400 million.
A military Satellite’s most common missions are for intelligence gathering, navigation, and military communications.