What is a launcher?
A launcher is the vehicle used to put satellites or space probes to other planets into space. To understand how important launchers are, first we have to appreciate the importance of satellites. Satellites are used for communications; weather forecasting; navigation; observing land, sea and air; scientific research; and military reconnaissance.
Their shape has changed considerably since the first satellite - the Russian Sputnik - was launched in 1957. Today’s satellites have large solar panels to collect power from the sun, and satellite dishes to gather and transmit information from and to the Earth, day and night, whatever the weather.
To escape from the Earth’s atmosphere a launcher has to travel 150 km at a speed of more than 7.9 km per second. If a satellite were put into orbit lower than 150 km it would rapidly burn up in the atmosphere.
Satellites can be launched into circular or elliptical orbits. Once the chosen orbit is reached, small engines on board the satellite thrust it into its precise position. These engines are also used to correct the satellite’s trajectory during orbit if it is pulled off course by the gravity of the Earth, other planets or by solar wind forces.