Satellites orbiting the Earth can be used for civilian or military purposes.
satellite, satellite types, Global Positioning System, GPS, International Space Station, ISS, Hubble, Cloudsat, GOES, Galileo spacecraft, reconnaissance satellite, space probe, space station, space research, telecommunication, meteorology, astronomy, geography
GPS is an advanced positioning system that allows 3 dimensional positioning, timing and speedmesurement on land, sea or in air. Accuracy is typically within a few meters. The system operates with 31 NAVSTAR satellites, each completing 2 orbits per day, 20,200 km (12,550 mi) above the surface of the Earth. Their location is such that at any moment at least four of them are visible from any point of the Earth. The 31 satellites are divided into six groups, they orbit the Earth in planes inclined at 60 degrees. From flat terrain 7–12 satellites are visible at a time, of which three are necessary for positioning, and one more for determination of altitude.
International Space Station
The space station orbits the Earth on a 360 km (223.7 mi) altitude, low-Earth orbit, every92 minutes. Upon completion of construction, the pressurized volume of the ISS will be 600 m³ (21,190 ft³), mass 400 tonnes, power output 110 kW, total length 108.4 m (355.6 ft), length of the modules 74 m (242.8 ft), with a 6 member crew.
Astronomical satellite, in a 569 km (366.6 mi) altitude, low-Earth orbit, orbiting the Earth once every 96 minutes. It measures 13.2 m (43.31 ft) in length, 4.2 m (13.78 ft) in diameter and weighs 11.1 tonnes.
Meteorological/Earth observation satellite for the detailed examination of clouds. It orbits the Earth every 100 minutes at a 700 km (435 mi) altitude. It has a special polar orbit, sun-synchronous orbit, it scans the entire surface of the Earth's with its sensors.
One of the 31 satellites of the Global Positioning System. It orbits 20,200 km (12,550 mi) above the Earth, twice a day. It weighs 2 tonnes.
Meteorological and research satellites. Geostationary satellites at 35,790 km (22,240 mi) altitude. Permanently within view of a given ground station on Earth. Orbital period is equal to the Earth's rotation period, 1 day.
One of the telecommunication satellites orbiting above Europe. Its orbit is geostationary, at a 35,790 km (22,240 mi) altitude. It is permanently within view of a given ground station on Earth. Its orbital period equals the Earth's rotation period, 1 day. Mass: 824 kg (1,817 lb).
Satellites for military purposes, mostly with a secret mission. Mainly used for monitoring purposes. Civilian satellites often carry military equipment and vice versa (see GPS). The first military observation satellites were equipped with analog cameras, returning the films to Earth with parachutes.
Unmanned research spacecraft. A space probe launched in 1989 to observe the moons of Jupiter. It reached Jupiter in 6 years. The probe worked until 2003, it was then guided into the atmosphere of Jupiter where it burned. Its mass was 2,223 kg (4,901 lb).