Satellites cover a wide range of functions from enabling communications to monitoring disasters. We have launched many of them into space over the last 60 years.
Using satellites to communicate
Communication satellites were one of the first types of satellite built. Further from the surface of Earth than communication towers, these satellites could send signals much further, connecting remote and distant locations more easily. Most communications satellites are in geostationary orbit above the Earth at around 36000km.
One of the first communication satellites to launch was Telstar 1. This satellite was a joint project between the USA, France and the UK, designed to relay signals across the Atlantic Ocean.
Radio waves have been used for navigation since before World War I. Using this technique with a network of transmitters in orbit around the Earth meant unprecedented levels of accuracy for global navigation.
Most satellite navigation has been handled by two networks, Russian GLONASS and the US GPS. In 2020, a new network will be completed by the European Union called Galileo. This network will be able to track objects down to an astonishing 1cm accuracy.
Remote sensing satellites
Remote sensing satellites are used to gather information about an object while orbiting around it. Around the Earth, they are used for a variety of purposes, including weather forecasts, land surveying and humanitarian applications. The second half of this section expands a bit on these.
Remote sensing satellites are also one of the most common types of satellites sent to orbit objects other than the Earth. These satellites are used by the scientific community to carry experiments to planets, moons and other celestial objects, so that we can investigate them without having to physically transport people there.