Spacecraft in orbit for communication, navigation, weather, Earth observation, science, defense, and exploration
Artificial Satellites
Artificial satellites are human-made spacecraft placed in orbit around Earth or another body. Since Sputnik 1 in 1957, satellites have become part of daily infrastructure, supporting weather forecasts, television, internet links, GPS navigation, climate monitoring, disaster response, scientific research, and national security.
What they are
An artificial satellite is a human-built object placed in orbit around Earth, the Moon, another planet, or another body. It stays in orbit because its forward motion and gravity balance in a continuous fall around the body below. Most satellites are uncrewed machines, though space stations are also artificial satellites.
How satellites stay in orbit
A launch vehicle accelerates a satellite high above the atmosphere and sideways fast enough that it keeps missing Earth as it falls. Low Earth orbit requires very high speed, while higher orbits move more slowly but need more energy to reach. Engineers choose altitude, tilt, and path according to the mission.
Major orbit types
Low Earth orbit is useful for imaging, science, space stations, and many internet constellations. Medium Earth orbit is used by navigation systems such as GPS. Geostationary orbit lets a satellite appear fixed above one point on the equator, which is useful for communications and weather monitoring. Polar and sun-synchronous orbits help observe the whole planet over time.
What satellites do
Satellites relay phone, television, internet, and data signals; measure clouds, storms, oceans, fires, crops, ice, and cities; guide aircraft, ships, cars, and phones; study space weather and astronomy; and support military reconnaissance and communications. One satellite may carry cameras, radar, antennas, clocks, sensors, computers, and propulsion.
Earth observation
Earth-observing satellites are essential for weather forecasts, climate records, disaster mapping, agriculture, ocean monitoring, and environmental protection. They can see patterns too large, remote, dangerous, or fast-changing for ground observers alone. Satellites do not replace local knowledge, but they give a broad and repeated view of the planet.
Risks and limits
Satellites face radiation, temperature swings, micrometeoroids, limited fuel, launch vibration, cyber threats, and orbital debris. Crowded orbits increase collision risks, while bright satellite constellations can affect astronomy. Satellites can also raise questions about surveillance, military escalation, unequal access, and who governs shared orbital space.
Why it matters
Artificial satellites matter because much of modern life quietly depends on space infrastructure. A forecast, map route, bank transaction, emergency alert, live broadcast, crop estimate, or climate dataset may rely on signals from orbit. Understanding satellites helps people see both the benefits and responsibilities of using near-Earth space.