How did satellite get into the "run" orbit? Can you still "run" along the track?
More than a thousand artificial satellites orbit the earth every day. These satellites play an important role in many fields, such as global digital communication systems, weather forecasts, radio and television signal transmission, military operations, and a wide variety of other key areas that far-reachingly affect human lifestyles and civilizations.
GOES-8, a retired American weather satellite (Photo source: NOAA In Space Collection / Wikipedia)
However, when you watch the live broadcast of the Yankees baseball game or a video of your friend who is thousands of miles away, are you curious about how this process is completed? How did the satellite be launched into orbit around the Earth so that it could stay there for years or even decades?
How is the artificial satellite launched?
Each artificial satellite has a very clear purpose. Some satellites are designed to observe various geographical events in a certain area, and some are used as spy satellites, but many are still launched by private organizations to broadcast global communication signals. Regardless of the type and purpose of these artificial satellites, each satellite must reach a specific orbit, that is, to an orbit (sphere) orbit.
Types of Earth Orbit (based on altitude)
is divided according to the height of each of these satellites from the Earth's surface. There are four main Earth Orbits, low-Earth Orbit (referred to as LEO, in this orbit of the International Space Station), medium Earth Orbit (referred to as MEO, which is the orbit where the GPS satellite is located), geostationary orbit and high Earth Orbit (referred to as HEO, which only contains a small number of satellites, such as NASA's interstellar boundary detector).
orbit height, the height of different orbits orbits (Image source: Rrakanishu/Wikipedia)
So far, most functional satellites operate on low-Earth orbit LEO, while others are in geostationary or mid-Earth orbit MEO.
An artificial satellite requires a very high horizontal velocity to reach its orbit.
An artificial satellite does not have enough acceleration power to rise by itself and pass through the thick atmosphere to reach space. To help it achieve this, it was attached to the launch vehicle , which was able to rapidly accelerate the satellite before it eventually detached and fell back to Earth.
Illustration of the rocket launching into space
Due to an interesting physical phenomenon, Sir Isaac Newton first proposed the assumption that the rocket should not rise in a straight line, but should enter orbit along a curved route (orbit).
Newton cannon
Suppose you have a cannon that can fire the shells you want to fire. In order to make the shells fired as fast as possible, you obviously need to fire on a high ground (so the shells can be in its path without obstacles). Now, the more fire you fire the shell, that is, the faster the horizontal speed of the shell, the further it flies before landing.
If you keep increasing the horizontal speed of the shell, at a certain point (when the horizontal speed reaches 7,300m/s), the shell will fly fast enough to not land! Instead, shells will continue to surround our earth in a fixed orbit. The following animation will help you imagine it better:
As shown in Figure C, it is a trajectory with a horizontal speed of 7,300m/s
also applied the same principle when launching artificial satellites. In order to pass through the thickest part of the atmosphere as quickly as possible, it is emitted vertically. But once it reaches a predetermined height, most rockets' driving force is used to increase horizontal speed so that it can enter a fixed orbit orbit.
This is why the satellite is launched along the parabolic trajectory rather than being launched upwards in a straight line.
A rocket's path, pay attention to how the rocket's path gradually becomes curved (Image source: pixabay)
Since the earth's gravity is the largest in low-Earth orbit, satellites in low-Earth orbit are subject to stronger Earth's gravity than those in Earth orbit or geostationary orbits. Because of this, low-Earth orbit satellites "fly" faster than those in higher orbits (that is, they have higher orbital speeds and orbit faster).
ISS (International Space Station), the International Space Station is launched in low-Earth orbit, and it orbits the earth at an extremely fast speed of about 8 kilometers per second. To get a better idea of how fast it is, think about it: if you fire a shot at one end of the football field, the International Space Station will fly out of the length of a football field before the bullets fly out 10 yards (about 914.4 cm)! (Photo source: Wikipedia)
Now we have the understanding of how satellites are launched into orbit in our minds, so let us continue to understand how satellites stay in orbit independently for so long. How does the
satellite run in orbit for several years?
Here, it can be explained by the experiment of Newton's cannon's thought. In order for the satellite to remain in its orbit, it must circle the Earth at an amazingly super-fast speed so that it does not fall straight onto the Earth. Such a high speed is achieved by the satellite with the boost of its own engine (after the rocket was abandoned by the satellite).
Please note that these satellites have always tended to fall to the ground. It is only because of their extremely high horizontal speed that they continue to fly toward the ground while the earth becomes a curved surface beneath them (so that satellites cannot hit the ground). However, those near-Earth satellites will also still lose their altitude (or experience ‘orbital attenuation’) faster than those operating in higher orbits.
The International Space Station undergoes about 100 meters of "orbital attenuation" every day. In other words, the International Space Station loses an altitude of 100 meters every 24 hours. (Photo source: Wikimedia Commons)
Satellites like this (including the International Space Station) must continue to accelerate to maintain their orbit to avoid falling back to Earth and crashing.
In short, the faster it falls to the earth. To make sure that this doesn't happen, it has to have a high level of speed, which means spending a lot of money to equip the satellite with adequate fuel and all the necessary parts. That's why people say that 'satellite business' burns a hole in your pocket, it's a bottomless pit!
Reference
1. Wikipedia Encyclopedia
2. Astronomical noun
3. Ashish-U_Uranus
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