If you are one of those who enjoy researching about the outer space and advanced space technologies then you will be interested in knowing in depth what a satellite and what they are used for. Below, we will not only explain the concept, but also how they have evolved, their technological importance and how these devices are key to our daily lives.
What is a satellite?
A satellite can be defined as any object that orbits a larger bodySatellites can be natural, like the Moon, or artificial, that is, built by humans to perform certain functions. Artificial satellites, in particular, are launched into space and operate around planets or stars for a wide range of scientific, communication, navigation, and even military purposes. Usually, when we talk about satellites in a current context, we are referring to those artificial satellites which are placed in orbit around the Earth to facilitate tasks such as obtaining images from space, supporting telecommunications, weather forecasting, or GPS navigation.
How are satellites placed in space?
Satellites are placed in space using rockets or space shuttles that generate enough power to overcome Earth's gravity. Once in the desired orbit, the satellites continue to orbit the planet, mainly thanks to the balance between the gravity and the speed at which they travel. This balance prevents satellites from falling back to Earth. Most satellites launched today are powered by multistage rockets. These rockets are designed to shed sections of their structure as they ascend, allowing them to reach sufficient speed to bring the satellite into a stable orbit.
What are artificial satellites used for?
Artificial satellites have multiple functions in various fields:
- Telecommunications: One of the most widespread uses of satellites is in the field of telecommunications. These satellites are responsible for facilitating the transmission of data over large distances and between different parts of the world. From telephone communications to satellite television and the Internet, these devices allow signals to travel great distances without significant interruptions.
- Climate detection and monitoring: Weather satellites allow us to monitor the weather accurately. They allow us to obtain more accurate forecasts and predict extreme events such as storms or hurricanes.
- Navigation and GPS: Without satellites, the use of global navigation systems such as GPS (Global Positioning System) would be impossible. These satellite networks provide position information with an accuracy of up to a few metres.
- Scientific investigation: Satellites are also key tools for space and terrestrial exploration. From studying the atmosphere to observing deep space or detecting exoplanets, their role is fundamental to modern science.
History and evolution of satellites
El first artificial satellite of the world was the Sputnik 1, launched by the Soviet Union on October 4, 1957. This event marked the beginning of the space age and an intense race between the world's superpowers for domination of outer space. Sputnik 1 was intended to collect data on the highest layers of the Earth's atmosphere. Although it was an extremely simple device compared to modern standards, its success proved that satellites could be a practical reality. Shortly afterward, in 1958, the United States launched its first satellite, the Explorer 1, which was instrumental in the discovery of the Van Allen radiation belts.
Types of satellites
There is a wide variety of satellites depending on their function and orbit. Below we detail the most common ones:
According to its function:
- Communications satellites: Used to transmit radio, television and telephone signals over long distances.
- Weather satellites: Employees to collect meteorological data and make weather forecasts.
- Navigation satellites: They provide signals used to determine precise geographic locations. GPS is a great example of this type of satellite.
- Research satellites: Designed to study the cosmos, detect asteroids and perform scientific experiments in space.
According to the type of orbit:
- Low Earth Orbit: (LEO) Satellites that orbit at altitudes of up to 2.000 kilometers. They are common for observation tasks.
- Mean Earth Orbit: (MEO) Satellites are located at a distance between 2.000 and 35.000 kilometers. GPS satellites are usually in this orbit.
- Geostationary orbit: Here they are located at an altitude of 35.786 kilometres and rotate at the same speed as the Earth. Telecommunications satellites are usually in this type of orbit.
Satellite lifetime and space debris
Even when a satellite completes its mission, it does not always withdraw from orbit. Many of them remain as space junk, which can pose a risk to other satellites and future missions. As satellites age, their propulsion and communication systems can fail, leaving them inoperative and adrift. Space debris is a growing problem. There are efforts to try to clear Earth's orbit of this debris, and new satellites are being designed with plans to allow for controlled reentry into the Earth's atmosphere for disintegration.
Importance of satellites in modern life
Satellites are absolutely crucial to modern life. Without them, we would not have basic services such as satellite television, long-distance telecommunications, or GPS navigation systems. They also provide critical data to address global challenges such as climate change, natural disaster management, or air traffic control. Satellites also play a strategic role in the national defense and security of many countries, providing essential information for monitoring military activities and recognizing threats. Over the past few decades, satellite technology has advanced enormously, allowing space missions to become increasingly complex and ambitious. The most recent plans include dedicated satellite constellations to provide global internet coverage from space, such as Starlink.