Did you know? Artificial Satellites
This month . . . Artificial Satellites. From the launch of Sputnik which lead to the start of the Space Race between the Soviet Union and USA artificial satellites play an important part of our life.
Unlike natural satellites such as the Moon which orbit the Earth, artificial satellites are human-made and are deliberately sent into orbit in space. The International Space Station (ISS) is the largest artificial satellite currently orbiting Earth.
The oldest artificial satellite still in orbit is Vanguard 1 launched by the USA on 17th March 1958. Although no longer operational, communications with the satellite were lost in 1964, it will remain in orbit for centuries to come.
The speed an artificial satellite must travel to stay in space is called its orbital velocity. It usually needs to be more than 28,200 kilometres per hour.
On the 29th November 1967 Australia launched WRESAT from Woomera Test Range, South Australia, making Australia the seventh nation to have an artificial satellite launched, and the third nation to launch one from its own territory.
Artificial satellites are crucial to our everyday life. Fixed satellite services handle billions of voice, data, and video transmissions: mobile satellite systems are used for navigation (GPS): and scientific research satellites are used for meteorological data, land survey images, and other scientific research functions.
A geostationary satellite orbits Earth from west to east over the equator. It moves in the same direction and speed as Earth is spinning, therefore as seen from Earth, these satellites do not appear to move. Polar-orbiting satellites orbit Earth in a north-south direction from pole to pole, so as Earth spins underneath they scan the entire globe strip by strip.