An Earth satellite can be placed into an infinite number of orbits. Each kind of orbit has its own specific features, and is chosen according to the mission objectives and technology constraints, such as altitude, solar illumination conditions, coverage and revisit frequency.

Among the different types of orbit used by Earth satellites (see table), two in particular afford special benefits:

Geostationary orbit: at an altitude of 35,786 km, a geostationary satellite appears to “hover” above the same spot on the Earth’s surface. In fact, it is moving at a speed of over 10,000 kph in the equatorial plane, and completes one orbital revolution in 23 h 56 min 04 s—exactly like Earth.
Because they offer vast coverage, geostationary satellites are ideal as relays for telecommunications and for keeping an eye on the weather.

^{Three geostationary satellites can beam data almost instantly around the globe.
Imagined by Jean-Pierre Penot (CNES) and Bernard Nicolas, illustrated by Bernard Nicolas}

Sun-synchronous orbit: a Sun-synchronous satellite passes over the same point on Earth at the same solar time. The orbital plane is always oriented the same way with respect to the Sun. Such satellites fly at altitudes of 600 to 800 km and offer major advantages for Earth observation, since they can observe the same area of interest in similar illumination conditions on every pass.

^{A Sun-synchronous satellite’s orbit maintains the same orientation with respect to the Sun all year round. This natural phenomenon is due to the irregular shape of the Earth.
Imagined by Jean-Pierre Penot (CNES) and Bernard Nicolas, illustrated by Bernard Nicolas}

Polar orbit: a polar-orbiting satellite passes over the Earth’s poles on each orbital revolution, typically at relatively low altitude. In an orbit inclined near 90°, a satellite can cover almost all of the globe, making it very useful for Earth observation purposes.