satellita

A satellita is any object that orbits another body in space. It can be natural, as the Moon does around Earth, or artificial, as a spacecraft placed into orbit by humans. The word is used in several Romance languages to describe both kinds of objects.

Orbits are governed by gravity and velocity. Satellites occupy different regimes, such as low Earth orbit (LEO), medium Earth orbit (MEO), and geostationary orbit (GEO). A GEO satellite stays above a fixed point on the equator, appearing motionless relative to the surface, while others follow various inclined or eccentric paths. Orbits can be circular or elliptical and are described by parameters such as period, semi-major axis, and inclination.

Satellites serve many purposes. Communications and broadcasting, navigation, weather forecasting and Earth observation, scientific experiments, and military reconnaissance are among the main uses. Modern systems often rely on constellations—groups of satellites working together to provide continuous coverage over large areas.

The artificial-satellite era began in the mid-20th century. The first artificial satellite, Sputnik 1, launched by the Soviet Union in 1957, marked the start of sustained space activity. Since then, thousands of satellites have been launched and operate in orbit around Earth, with growing importance for science, industry, and daily life.

Space activity is governed by international law and cooperation. Debris management, orbital-slot assignment, and responsible end-of-life disposal are key concerns, prompting guidelines and treaties to promote safe and sustainable use of outer space.