satillites

A satellite is any object that orbits a larger body due to gravity. Broadly, satellites are classified as natural, such as moons, or artificial, meaning human-made objects placed in orbit around a planet or other body. Artificial satellites carry payloads and systems that enable a range of functions, from sensing to communication.

Orbits are the paths satellites follow around their primary. Orbits are characterized by altitude, inclination, and shape. Low Earth orbit (LEO) typically lies from about 150 to 2,000 kilometers above Earth and completes an orbit in roughly 90 to 120 minutes. Medium Earth orbit (MEO) sits higher and often hosts navigation satellites. Geostationary orbit (GEO) is about 35,786 kilometers up, where a satellite’s orbital period matches Earth’s rotation, making it appear fixed over one location. Highly elliptical orbits are used for specialized missions. Orbital mechanics determine lifetime, visibility, and coverage for the satellite’s mission.

Historically, the launch of Sputnik 1 in 1957 marked the beginning of the space age. Early satellites demonstrated basic telemetry and science, followed by decades of communications, weather observation, navigation, and remote sensing missions. Today, thousands of satellites operate, including large constellations that provide global broadband.

Satellites consist of a bus that supplies power, attitude control, propulsion, and thermal management, plus a payload that performs the mission—cameras, transponders, sensors, or scientific instruments. They require ground support for command, data reception, and tracking.

End-of-life plans include deorbiting, using a graveyard orbit for GEO satellites, and debris mitigation to minimize space junk. International coordination on frequency use, orbital slots, and safety standards governs satellite operations. Emerging trends include small CubeSats, mega-constellations, and sustainable design practices.