A low Earth orbit (LEO) is usually described as an orbit inside the area which comes from the Earth’s surface up to an altitude of 2,000 kilometres (1,200 miles). Other definitions use other numbers such as orbital eccentricity and orbital period. Satellites in LEO go around the Earth many times per day.
Satellites are put in low Earth orbit if the things they do must be done in outer space but need not be far away. Some satellites are in LEO to photograph the Earth, for example some weather satellites and Earth resource satellites. Most space telescopes are in LEO since they only have to be above the Earth's atmosphere. The International Space Station is in LEO.