Why Don't Satellites Fall to Earth? This is the explanation
Satellites are one of mankind's greatest technological achievements. Until now, satellites have turned out to be very crucial in sustaining human life on planet Earth.
Satellites have many uses depending on the type. Some are used to forward telephone and television signals, Earth observations, weather monitoring, to navigation. Because of that, satellites are very important in modern human life.
Before entering into the main discussion, it would be nice if we knew in advance about satellites in more depth.
What is Satellite?
A satellite is an object that orbits another object in space with a certain period of rotation and revolution. Satellites can be divided into two types, namely natural satellites and artificial satellites.
Based on the explanation above, the Earth can be classified as a satellite because it orbits the sun, and so does the moon orbiting the Earth. Meanwhile, artificial satellites are man-made objects that evolve in outer space.
Artificial satellites have the main function as a receiver and transmitter of radio communication signals. In addition, artificial satellites are also commonly used by meteorologists in predicting the weather.
There are two types of artificial satellites, namely manned and unmanned satellites. One example of a manned satellite is the United States Space Shuttle. While the unmanned satellites include communication satellites, weather satellites, navigation satellites, and others.
Until now, there are around 2,700 satellites in operation. These satellites circulate in orbits that have been arranged and defined. There are many satellites orbiting at the low or polar equator that circulate from North to South of the Earth.
The first man-made satellite was Sputnik 1 which was launched by the Soviet Union in 1957. The launch of this first satellite also marked the beginning of the space race between the Soviet Union and the United States. In addition, Sputnik 1 also became the beginning of space exploration carried out by humans.
The average size of a satellite is the size of a bus with the International Space Station (ISS) as the largest artificial satellite with a size almost the size of a football field. Until now, the ISS is still being developed with an estimated weight of up to 450 tons when it is perfected.
Then why don't satellites fall to earth?
A satellite is sent into orbit using a high-speed rocket 100 to 200 km above Earth to escape the atmosphere. When the rocket reaches the specified orbit, it will begin to be directed sideways at a speed of up to 18,000 miles per hour.
After that, the rocket will turn off its power and then drop the payload in the form of the satellite it carries, until then the satellite is in orbit and glides at the same speed.
As we know, the lower the Earth's atmosphere, the higher the density of the air, this can destroy the satellite and burn due to the great friction with the air. Because of this, most satellites are dropped at an altitude of 2,000 km above the Earth's surface.
Technically, the satellite actually always falls, but is deflected by its initial velocity at launch, which is 28,000 km. When an object has passed through the atmosphere, then gravity is no longer strong enough to pull the object back to Earth, but still enough to keep the object in orbit or around the Earth.
The earth is curved while the satellite is falling sideways at a very high and steady speed. Because of this speed, satellites always manage to evolve before they get close to Earth.
The satellite moves in two directions, namely to the center of the Earth and laterally to the perpendicular to the Earth's surface due to the acceleration when launched sideways. The combination of these two types of forces is known as circular motion. This motion was also described by Isaac Newton through the "Newton Cannonball".
In order for a satellite to remain in its orbit, it must have a force similar to that of the Moon, which is Earth's natural satellite. The difference is in the Earth's gravitational force on the artificial satellite which is larger because it has a closer distance than the Moon.
To get a balance between the Earth's gravitational force and the moving away force, the artificial satellite must have a speed higher than the speed of the Moon. If it moves too slowly, the satellite will fall back to Earth. On the other hand, if it moves too fast, the satellite will move away from the Earth's gravity.
The balance of the two forces can be achieved if the speed of the satellite is in the range of 27,000 km / h as on the ISS, or 16,000 km / h on GPS satellites which have different distances from Earth. At that speed, the satellite will continue to circulate around the Earth.
The fall of an artificial satellite can be due to running out of fuel, poor components, to errors in orbital altitude.