Satellit

Satellit is the term used in several languages for an object that orbits another body. A satellit can be natural, such as the Moon, or artificial, a human-made spacecraft placed into orbit to perform specific tasks. Artificial satellites carry power sources, communication links, attitude control systems, and payloads for observation or experiments. They are launched by rockets and placed into a chosen orbit around Earth, the Moon, or other planets.

Orbits and classes: Satellites occupy various orbital regimes. Low Earth orbit (LEO) ranges from about 160 to 2,000 kilometers and allows high-resolution imaging and low-latency communication. Medium Earth orbit (MEO) extends roughly from 2,000 to 35,786 kilometers. Geostationary orbit (GEO) at about 35,786 kilometers keeps a satellite fixed above the same point on the equator, facilitating continuous communications and weather monitoring. Polar and sun-synchronous orbits pass over the poles and enable global coverage and consistent lighting for imaging.

History and impact: The first artificial satellite, Sputnik 1, was launched by the Soviet Union in 1957, initiating the space age. Since then, thousands of satellites have been deployed for telecommunications, global positioning (GPS), weather forecasting, Earth observation, and scientific research. The International Space Station is a large, manned satellite in low Earth orbit, while many companies are deploying large constellations of small satellites to provide broadband and other services.

Challenges and outlook: Space debris, collision risk, radio interference, and regulatory coordination are ongoing concerns. Advances in small satellite technology, reusability, and on-orbit servicing continue to shape the evolution of satellit programs.