Satellites refer to celestial bodies that orbit planets in a cyclical movement. While natural satellites are commonly referred to as satellites, artificial objects such as rockets and spacecraft that revolve around the earth are also called satellites.

With rapid advancements in science and technology, humans have expanded their exploration beyond earth and directed their efforts towards the stars. Artificial satellites are the closest and most significant development that enables humans to achieve this.

Satellites can be classified into earth satellites or satellites of other planets. Earth satellites can further be categorized into natural satellites and artificial earth satellites.

Artificial satellites have a significant impact on our lives, with communication equipment such as mobile phones and recording camera equipment heavily relying on satellites. We also receive TV broadcast signals, navigation positioning information, and earth resource information through satellites. Our lives have become intertwined with satellites.

From an external perspective, satellites look like big birds soaring in the sky. The long "wings" are solar electric boards that convert solar energy into electrical energy to power the satellite.

The operation of artificial earth satellites relies on the gravity of the earth, causing the height of the satellite to decrease gradually during operation. Therefore, rocket engines must be started periodically to increase the satellite's height.

When the rocket fuel is exhausted, the satellite is gradually attracted to the earth by gravity and eventually falls to the earth or burns in the atmosphere.

However, the risk of satellite falling is minimal since their orbits are scientifically and reasonably designed to fall into the sea. Related personnel will then recover them as soon as possible to prevent injury.

Artificial satellites operate on their own track, each with a specific function and use. They can be categorized into five groups: communication, meteorological, resource, investigation, and navigation.

Communication satellites convey TV and phone signals to humans and provide internet access.

Without them, we cannot communicate or watch world news programs.

Meteorological satellites employ remote sensing technology to monitor changes in the earth's atmosphere, providing feedback on meteorological changes and global weather data.

Earth resource satellites use remote sensors to detect various plants, geology, and resources on the ground.

Investigation satellites carry high-resolution cameras that capture ground movements, mainly used in defensive operations.

Navigation satellites include the GPS positioning system, which provides significant convenience for transportation and travel.

Artificial satellites have also played a significant role in scientific research, with various satellites launched for space exploration and astronomical observations. The Hubble Space Telescope, launched in 1990, has provided us with countless images of the universe, revealing its beauty and secrets.

The Kepler Space Telescope, launched in 2009, has discovered numerous exoplanets outside our solar system, deepening our understanding of the universe and the possibility of life beyond earth.

Satellites have also contributed to disaster management and emergency response. During natural disasters such as earthquakes and hurricanes, satellites provide critical information that aid in rescue and recovery efforts. They help track the movement of storms, monitor flooding, and assess damage caused by natural disasters.

Satellites also play an essential role in national security and defense. Some satellites provide intelligence and communication capabilities, giving governments the ability to monitor global events and respond to threats. Satellites provide essential data for defense planning, enhancing the security of nations around the world.

Artificial satellites have revolutionized our lives in countless ways. They have improved communication, provided vital information for weather forecasting and resource management, and opened up new frontiers for scientific exploration.

As technology advances, we can expect satellites to continue to play an increasingly important role in shaping our world and expanding our understanding of the universe.