- A satellite is any object that orbits around another object in space, typically due to gravitational forces. In modern usage, the term most commonly refers to artificial satellites—human-made devices launched into orbit around the Earth, other planets, or the Moon to serve a variety of purposes. These purposes include communications, navigation, earth observation, weather forecasting, scientific research, and military applications. There are also natural satellites, such as Earth’s Moon, which orbit celestial bodies without human intervention.
- Artificial satellites are launched into space by rockets and can be placed in different types of orbits depending on their function. These include low Earth orbit (LEO), medium Earth orbit (MEO), geostationary orbit (GEO), and polar orbit. For example, satellites in LEO are commonly used for Earth imaging and the International Space Station (ISS), while those in GEO are ideal for communication purposes, as they appear stationary relative to a fixed point on Earth.
- Structurally, satellites typically consist of several key systems. These include a power source (often solar panels and batteries), communication systems for sending and receiving data, propulsion and attitude control systems to maintain or adjust their position, and payload instruments tailored to their specific mission. For instance, a weather satellite might carry sensors to measure atmospheric temperature and moisture, while a GPS satellite would carry highly accurate atomic clocks for precise timing.
- Satellites have revolutionized life on Earth. Communication satellites enable global broadcasting, internet access, and real-time telecommunication across continents. Navigation satellites, such as those in the Global Positioning System (GPS), support location services essential for aviation, maritime transport, military operations, and daily civilian use such as navigation apps. Earth observation satellites provide critical data for monitoring environmental changes, natural disasters, urban development, and agricultural productivity. Meanwhile, scientific satellites like the Hubble Space Telescope or James Webb Space Telescope expand our understanding of the universe by studying stars, galaxies, and cosmic phenomena.
- In addition, satellites are central to weather forecasting, as they provide meteorological data that allow scientists to predict storms, monitor hurricanes, and analyze climate patterns. Military and intelligence satellites are also deployed for surveillance, reconnaissance, missile detection, and secure communications, playing a crucial role in national defense strategies.
- The deployment and operation of satellites are governed by international treaties and regulations, including the Outer Space Treaty, which emphasizes the peaceful use of space. However, with the rapid increase in satellite launches—especially due to commercial ventures like SpaceX’s Starlink, OneWeb, and others—issues such as space debris, orbital congestion, and radio frequency interference have become significant concerns, prompting discussions on sustainable space governance and satellite traffic management.
