As of January 2022, the number of satellites in space was more than eight thousand. However, some of them are no longer active. The biggest hurdle in sending them into space is dodging Earth's strong gravity. How is this almost impossible task done? After reaching space again, by what technique can they travel around the earth in a balanced orbit? And how on earth are they managed? If you don't know the answer to these questions, let's find out.
release velocity
Suppose you have a tennis ball in your hand. You're determined to shoot it aloft and accompany the rumble of an artificial satellite. Because, with all your heart, you believe that one day robots will take over the world using them. So they have to stop to have time. However, you throw the ball upwards with all your might. Can it even reach artificial satellites?
Unless you're superman, the ball will definitely bounce up a bit and then start to come down with a huge bang. How high the ball can go will depend entirely on your muscle strength. The harder you throw, the higher the ball will go. The main mechanism behind the tennis ball losing its momentum and falling down is the gravitational force of the earth. It's not just tennis balls; Rather, the invisible binds the earth's surface and everything around it in a strong bond.
A tennis ball has a certain amount of kinetic energy at the moment it is thrown upwards. It works in the opposite direction of the Earth's attraction. When the kinetic energy is completely exhausted, it begins to fall downwards. But if we could throw it hard enough, it would completely resist Earth's gravity. Physicists can easily calculate the value of this kinetic energy using calculus.
If an object on Earth could travel at least 11.2 kilometers per second, it could easily bypass gravity and go into space. Scientists have named this velocity Muktibeg. Its value varies depending on the planet or star. For example, if an object travels from the surface of the sun to reach space, it has to travel about 617.5 kilometers per second. This is because the size of the Sun is many times that of the Earth. That is, the value of the release velocity completely depends on the mass and radius of the planet or star.
The answer to a strange mystery of nature can be found through freedom of movement. Let's explain a little. The two lightest elements in the periodic table are hydrogen and helium. They are quite readily available. It is found everywhere in the universe including the earth. They are gaseous in normal state. As such, they are supposed to be present in the Earth's atmosphere. But the strange thing is that they can hardly be found there. Why is that?
The average kinetic energy of an atom depends on temperature. For the same temperature, atoms of lighter gases have higher kinetic energy and atoms of heavier gases have lower kinetic energy. At normal temperature, the average kinetic energy of hydrogen and helium atoms is greater than the Earth's release velocity. As a result, they can easily go into space. On the other hand, the relatively heavy atoms like nitrogen, oxygen etc. are trapped in the atmosphere due to their low speed. As a result, almost 99 percent of the air is made of them. And despite being abundant throughout the universe, hydrogen and helium are very rare in the atmosphere.
Now let's dispel a common misconception. It is not always necessary to travel at a speed equal to or greater than the velocity of freedom to overcome the attraction of the earth. This will only be true if there is no opportunity to apply the acceleration separately after taking off. Think again about the example of throwing a ball. After the ball leaves the hand, its velocity continues to decrease. There is no way to increase speed by applying acceleration at this time even if desired. So to escape Earth's gravity, the ball must start traveling at 11.2 km/s. But if somehow acceleration can be created by applying force on it, then it is possible to reach space by traveling at a much lower speed. Exactly this technique is used in rockets.
Along with the rotation around the sun, the earth also rotates on its axis. If we want to use it, we can make the value of the release velocity more or less. If we travel in the same direction as the Earth's rotation to go to space, then the value of the release velocity will decrease. And if you travel in the opposite direction of the earth's rotation, the opposite will happen. In this method, the release velocity can be increased up to 10 percent. The value of rotation of the earth on its own axis is greatest near the equator. As a result, traveling from this region can take maximum advantage of reducing the release velocity. Hence most of the world's rocket launch facilities are located here.
