low Earth orbit (LEO)
Definitions of low Earth orbit (LEO) vary. According to some, LEO includes orbits having apogees (high points) and perigees (low points) between about 100 kilometers and 1,500 kilometers. Others extend that range up to 2,000 or 3,000 kilometers. In some cases, the distinction between LEO and MEO (medium Earth orbit) is dropped and LEO is considered to be any orbit below geosynchronous altitude. The majority of all satellites, as well as the Space Shuttle and International Space Station, operate from LEO.