Countries have launched so many satellites, is there a saturation point in the number of launches? Will it collide?

The number of satellites launched at present is far from the saturation point. Since the 1950s, there has been only one satellite collision, but the collision is not due to the saturation of space satellites, let alone the crowded orbit.

Perhaps when we browse the pictures of space junk around the earth, we will find that there are tens of thousands of satellites and debris around the earth, and it is easy to collide in such a crowded orbit. In fact, this kind of map is enlarged, the earth shrinks and then the satellite enlarges. If calculated according to the actual proportion, the earth is more than n times larger than the satellite, and the satellite in the picture cannot be presented to the naked eye, just like the ratio of our human body to bacteria.

When launching satellites, countries all over the world will basically register and calculate the corresponding orbits, running in their own fixed orbits, and each road will basically not collide unless the orbit calculation is wrong, just like the collision between the US and Russia satellites in that year, which was caused by the orbit calculation error of the US satellites, but this is really a small probability event.

The orbit of an outer space satellite is not a fixed plane, but it can run 360 degrees without dead ends, with infinite width and height, which is completely different from the plane road of the earth. Of course, there will be more and more satellites in the future, and the possibility of collision will not be ruled out, because some secret military satellites may not be in public orbit. Once a collision occurs, it will not only hurt itself, but also the debris generated will spread to the surrounding satellites.

Countries have launched so many satellites, is there a saturation point in the number of launches? Will it collide?

Man-made satellites are man-made equipment that people launch into different orbits of the earth through rockets for different needs such as communication, meteorological monitoring, navigation, reconnaissance, surveying and mapping, agriculture and environmental protection. In people's impression, the space above the earth is very vast and should be able to accommodate many satellites. So is there a saturation point that can bear the largest number? The answer is yes, because after all, the effective orbit around the earth is limited by the height interval.

Satellite Orbit Before launching a satellite, the orbit of the satellite around the earth must be determined according to different purposes, and the heights of different orbits from the earth will be different. In the world, satellite orbits are usually divided into three regions: low orbit, medium orbit and high orbit according to the orbital range at different heights from the earth.

Of course, the lower the orbit, the better, because according to the formula of gravity and centripetal force:

We can calculate the minimum speed required for a satellite to make a uniform circular motion around the earth:

v= ( GM/r )^( 1/2)

R is the distance from the center of the earth. It can be seen that the closer to the ground, the greater the minimum velocity along the tangent direction of the orbit, the greater the initial velocity given by the rocket to the satellite, and the higher the energy required. If this speed is not reached, the satellite will fall back to the ground. At the same time, the density of the earth's atmosphere is still very high below the ground 100 km, although it is only one millionth of the air density above sea level, but for satellites, the friction between the satellite surface and air molecules is still very high below this height. Therefore, at the 53rd Barcelona International Aviation Congress in 1960, it was decided to define the space above the surface of 100 km as space, so as to ensure that the spacecraft can minimize the loss or damage caused by friction with air.

According to international practice, the space above 120 km and below 2000 km is defined as low orbit area; Determine the space above 2000 km and below 20000 km as the middle track area; Orbits over 20,000 kilometers are defined as high orbit areas. Of course, the higher the better, because the distance from the ground is too high. When it exceeds 36,000 kilometers, the motion speed will be lower than the earth's rotation speed, which makes it difficult to image and has little application significance. The main uses of satellites at different altitudes are different:

Because of the different heights of satellites, the time required in the launching process is long or short, and the work done by gravity to be overcome will be different. Therefore, different energy supply methods must be adopted when sending satellites with three altitudes into the predetermined orbit.

During the operation of the saturation point of the satellite, due to the influence of gravity fluctuation, high-energy particle impact and other factors, there will inevitably be some slight deviation between the actual orbit and the designed orbit, and the farther away from the earth and the longer the operation time, the deviation will gradually increase, and the adjustment of the satellite generally has a certain lag. Therefore, the international requirements for geosynchronous satellites generally require the satellite spacing to be greater than 1000 km. Therefore, the international maximum saturation point of synchronous satellites is 1800. At present, more than 300 synchronous satellites have been launched around the world.

Judging from all satellites in orbit, the closer the orbit is to the ground, the fewer satellites can be accommodated. If 1000 km is taken as the dividing line, the satellite data that the earth can accommodate in space should be around 40,000. At present, there are nearly 7,000 satellites launched into space in the world, and more than 3,600 satellites are still in space, which is still far from the upper limit. However, the value of 40 thousand is only the result of theoretical calculation, but in fact, due to the sudden deviation of satellite orbit and the influence of space junk brought by satellite launch, it should not reach this figure.

Of the nearly 7,000 man-made satellites that have been launched, more than 5,000 have failed (including those that have completed their missions and have not yet fallen into the earth), and only 1000 is still in operation, while more than 2,000 satellites that have remained in space and are no longer in operation have become "space junk", which has brought great hidden dangers to the operation of newly launched satellites and those that have already been launched. In 2009, a commercial communication satellite in the United States collided with a scrapped communication satellite in Russia in the air. With the increase of the number of satellites launched by human beings, it is estimated that the satellite collision caused by this uncontrollable factor will be staged again.

To sum up, a satellite orbiting the earth needs a stable orbital linear velocity and an orbital height that matches different uses. On the premise of ensuring availability, accuracy and safety, satellites must maintain the necessary safe distance and drift angle, so the number of artificial satellites above the earth must have a saturation point, estimated at around 40 thousand. Under the influence of uncontrollable factors and numerous space junk, with the increase of the number of satellites launched by human beings, the probability of satellite collision will become higher and higher, which has become a major problem that must be faced and solved as much as possible in the development of space industry in all countries of the world.

Previously, a Russian satellite collided with an American satellite, so the number of outer space satellites on the earth is increasing. Moreover, the space is smaller than we calculated. This is due to the explosion of spacecraft such as satellites, and the amount of debris produced by collision disintegration is very large, occupying a lot of space. A small piece of debris can also cause fatal damage to satellites in the same orbit or across orbits.

At present, there is no good way for science and technology to clean up the space junk around the earth, which makes the risk coefficient of launching and in-orbit operation of spacecraft such as satellites more and more large in the future. Especially for astronauts who walk in space and repair spaceships, it is more dangerous.

Finally, I want to talk about my personal thoughts. The development of human science and technology has gone from polluting the surface and underground to the space of the earth. I don't know what the ultimate goal of technology is.

Countries have launched so many satellites, is there a saturation point in the number of launches? Will it collide? On the morning of February/KOOC-0/0, 2009/KOOC-0//KOOC-0/point 55, two US and Russian satellites collided in the low-earth orbit over Siberia, making everyone realize that the vast space is actually bustling! This year is 2020. During the 1 1 year since the last collision, humans have launched a large number of satellites into the sky. Is this earth's orbit full of satellites? Is it possible to launch a spaceship in the future?

What are the orbits of the earth? What satellites are there in these orbits? In many popular science articles, it is said that the launch of satellites or spacecraft is in low-earth orbit. Of course, friends who know about space flight have a good idea of what mission to launch and how high this near-earth orbit is, but for most friends, this near-earth orbit is a bit embarrassing. What track is it?

How many orbits are there around the earth?

In fact, there is only one orbit around the earth, that is, the orbit around the earth, but the orbit around the earth has different heights and functions, which are generally divided into the following kinds of orbits:

In fact, there are many classifications, but all the tracks are too complicated to introduce. Let's choose a typical orbit description. Generally, the orbit below 1000 km is a special orbit for reconnaissance satellites, manned spacecraft, international space station and new communication satellites (such as Musk's star chain), because the lower the reconnaissance satellite flies, the clearer it can be seen. Of course, spacecraft also have geodesic satellites and satellites that study the earth's gravity field, and they also need as low an orbit as possible!

Orbit of the International Space Station

For example, the GOCE satellite launched by ESA in 2009 has an orbit as low as 260 kilometers. Because the molecular density of the atmosphere here is still very high, GOCE satellite even has a streamlined shape, and the ion engine continues to move forward, but it still ends its life hastily on 20 13 and falls into the atmosphere!

Most of the satellites in medium orbit (more than 2,000 kilometers in geostationary orbit and less than 36,000 kilometers) are GPS satellites, such as GPS satellites with an orbital height of 20,200 kilometers, GLONASS satellites with an orbital height of 1.9 1 0,000 kilometers, and Beidou satellites with an orbital height of 2 1.500 kilometers.

High-orbit satellites generally refer to 36,000-kilometer stationary satellites, but there are also very special ones, such as SOHO satellites running at the Lagrangian point of the Sun-Earth system or Queqiao relay communication satellites on the earth-moon system (Lagrangian point of earth-moon system).

Satellites with different inclinations and different functions

Along the equator of the earth, it forms a plane with the rotation axis, and this plane is the equatorial plane. Except for satellites rotating along the equatorial plane and satellites in geostationary orbit, there is an included angle between other satellites and the equatorial plane of the earth, which is the inclination angle of satellite orbit! Launch in the most fuel-efficient way, then the position of the launch site determines the inclination of the satellite!

Schematic diagram of Beidou satellite inclination angle

Of course, modern rockets don't count like the first satellite, so now spaceships and satellites are launched at calculated angles. If you are not satisfied, you can change the orbit (usually the rocket is in one step, and you need to use satellite fuel to change the orbit, which is extremely consuming the life of the satellite)!

The sub-star point in the inclined orbit is a wave curve, passing through different positions, while the satellite in the polar orbit makes an angle of 90 degrees with the equatorial plane, and its sub-star point passes through the pole. The advantage is that it passes through different sub-satellite points every turn, so it can detect all the positions of the earth in a few days!

There is also a special sun-synchronous orbit. Its height is about 600-800 kilometers, its orbital period is 96- 100 minutes, and its inclination angle is about 98 degrees. Precession matches the earth's rotation, so that it passes through the same position at the same time every day, and even rotates around the terminal line. Solar cells can always illuminate it, and most satellites that study the sun use this orbit!

stationary orbit

As we all know, the geostationary satellite looks motionless on the ground, but there is a tilted synchronous orbit that you may not have heard of. The orbit of this satellite is as high as that of the equatorial geostationary satellite, but the orbit is inclined and the point below the satellite is splayed. For example, satellites in equatorial geostationary orbit can hardly be seen in high latitudes of north and south latitudes, and tilted synchronous orbit satellites can solve this problem. Generally, high-latitude countries will use this communication satellite, such as Russia!

Can these tracks be packaged? Why did they collide again? There are too many orbits of satellites, only a few of which are introduced above. This orbit ranges from 200-300 km to 36,000 km. The orbital resources of these satellites are so rich that you can launch them at will. As long as it meets the requirements, check whether there are any existing or historical satellites in this orbit. As long as there is no conflict, you can insert satellites in this orbit! It's just that everyone grabbed the good track, so I feel there is no place to waste!

But there is really an orbit, and the total number of satellites is limited, and that is the equatorial geostationary orbit satellite! There is only one orbit, about 36,000 kilometers above the equator, and because the satellites will drift to a certain extent during the work, the allowable range is 0. 1 and the total circumference is 360, so it is very simple to calculate that there are 1800 satellites that can fit into this orbit. Does it look like a lot? In fact, there are many prime locations, such as the closest to the country and the dense country, so these positioning points have become the most sought-after resources!

space trash

Since the first artificial satellite was launched into the sky, nearly 7000 satellites have been launched into space, half of which are still in space, but only about 1000 satellites are still working normally!

If these satellites are controllable and can be tracked in the worst case, there are indeed many satellite orbit resources on the earth, but with the satellite out of control, the three-stage rocket when it is separated from the satellite, the debris of testing anti-satellite weapons, the debris of satellite collision, and of course, the garbage accidentally or intentionally discarded by astronauts from all over the world when they walk out of the cabin. More than 90% of these man-made objects orbiting the earth are rubbish, and many of them are too small.

But even so, there is still only the risk of collision, because the space around the earth is still too empty, just like a Beijing walking around the center of the earth, and another person walking around the center of the earth from Urumqi, the possibility of two people meeting somewhere is really small! But don't underestimate the harm, because every collision will increase the debris by a hundred times, and of course the probability of the next collision will also increase greatly!

Therefore, when detecting debris or satellites that may meet, the orbit will be changed in advance to avoid the danger of satellites! Among the two satellites that collided in 2009, Iridium 33 is still in service, while Russian cosmos -225 1 was launched in 1993, and it was scrapped in 1995! The two collided 790 kilometers above Siberia!

However, NASA still believes that this is only an extremely low probability event!

Can these scrapped satellites be recycled?

Although robotic arms and upper-stage rockets in various countries have important functions of collecting space junk, so far no space junk has been recovered! In the development process, there is also laser irradiation to change the orbit recovery. A British company also has a method, which is to shoot the net to increase the resistance and let it fall into the atmosphere early for recycling!

But they are not practical, because the cost of catching space junk is really too high. Orbit change is simple, requires a lot of fuel, and the transportation cost per kilogram is as high as tens of thousands of dollars. No country will waste its limited space budget with such a probability as low as1%%!

This is the aluminum alloy skin after the surface of the spacecraft was hit by space dust at high speed.

So up to now, in addition to avoiding detectable garbage, it is basically luck for those who can't be detected but can cause harm!

The outer space of the earth is a huge space. Judging from the number of satellites launched by human beings at present, it is still too early to reach saturation, but it is not easy to sit back and relax. On the contrary, the safety of orbit around the earth is imminent, because more and more space junk has seriously threatened the safety of satellites!

How big is the threat of space junk? As we know, all kinds of satellites launched by human beings have a life span. Under normal circumstances, these dead satellites will be scrapped and gradually slowed down by ground control until they fall into the atmosphere and become a wisp of smoke. Very few of them will accurately control the landing site (such as the Pacific Ocean) to ensure the safety of the ground. However, this is an ideal situation. The vast orbit around the earth needs extremely precise control. A flaw in any link may lead to failure, such as an out-of-control object flying in space orbit, such as a satellite out of control and a satellite component falling off. These objects fly very fast and pose a great security threat to other satellites in normal service.

In history, there have been many incidents in which space junk got into trouble, and there have also been many accidents in which space junk posed a threat to spaceships. For example, in 1983, the American space shuttle Challenger collided with paint flakes with a diameter of 0.2 mm, resulting in the damage of the porthole and had to suspend its work. 1986, the Ariane rocket exploded after entering orbit, and the rocket wreckage caused two Japanese communication satellites to "die"! .......

Space junk seriously threatens the safety of orbit around the earth. According to the data of the European Space Agency, there are currently 22,300 pieces of space junk that humans can track, but it is difficult to estimate the smaller space junk that cannot be tracked and has not been discovered. These space junk are like countless "stealth bombs", flying at high speed without control and colliding with each other, which may produce more junk and threaten the future human space program. Some scientists have calculated that the probability of catastrophic collision of each flying object in space orbit is 3.7%, which is too high for expensive spacecraft!

In view of the current threat of space junk, many countries have put space junk cleaning plans on the agenda. For example, the Japan Aerospace Exploration Agency and the European Space Agency plan to start space garbage recycling in 2022 and 2025 respectively. Some scientists have proposed using lasers to destroy space junk; Previously, a Swiss institution also tried to launch an aircraft similar to a space garbage collector, but the effect was average.

Satellites launched by various countries all make circular motions around the earth in near-earth orbit. The near-earth orbit is not just an orbit, but outer space outside the upper atmosphere of the earth's atmosphere. Strictly speaking, it can extend to the vast space in the orbit of the moon. The satellites launched by various countries will have specific data published, especially the distance between the satellite and the earth, which will be published accurately. Countries that launch satellites later will avoid this safety factor distance and form low-earth orbits with different distances. Therefore, the launched satellites can circulate in their own near-earth orbit without interfering with each other or affecting each other.

In addition, because satellites can choose the space position of low-earth orbit, it is a huge space area, and the volume of satellites is very small, so there will be no saturation point for the number of satellites launched, and satellites running at different distances in low-earth orbit will not collide. Only when two or more satellites are in low-earth orbit, satellites at the same distance from the earth will collide.

A: At present, there are more than 5,000 artificial satellites launched by human beings, of which more than 2,000 are in operation. The number of satellites in earth orbit is saturated, but it is far from saturated at this stage. Only some special orbits become valuable space resources, such as the orbital space of geosynchronous satellites.

On February/KOOC-0//KOOC-0/,2009, a commercial communication satellite of the United States and a scrapped military communication satellite of Russia collided over Siberia, with an orbital height of 434 kilometers, which became the only satellite collision event of mankind so far, but it was only a small probability event.

Today, humans have launched more than 5,000 satellites, of which more than 2,000 are working, and the rest have either fallen into the atmosphere and burned, or been pushed out of their original orbit and become out of control satellites.

When the satellite runs in the earth orbit, there will be a deviation between the actual orbit and the designed orbit due to the existence of errors, and with the passage of time, the deviation will become larger and larger. In order to ensure that the two satellites will not collide and the frequencies will not interfere with each other, countries will register with ITU when launching satellites.

For the general earth orbit, because the orbital space is three-dimensional and the time is four-dimensional, the artificial earth satellite can be placed above the orbital height of 100 km. For example, the orbital height of the International Space Station is about 350 kilometers. Considering the risk of collision and frequency interference, the orbits of two satellites generally leave a certain margin. If calculated in this way, the number of satellites in earth orbit is very large, far higher than the current number.

However, for some special orbits, it has extremely important application value. For example, the geostationary orbit plays a very important role. The height of the geostationary orbit is fixed at 36,000 kilometers, and there is only one geostationary orbit above the equator in theory, so the number of satellites that can be placed is very limited.

According to international regulations, only 1 1,800 artificial earth satellites can be placed in geosynchronous orbit at most, which is equivalent to keeping the distance between every two satellites above 1 1,000 kilometers, and the drift range of each satellite is 0. 1 to avoid collision and mutual interference.

Some special orbits are allocated to various countries according to a set of international rules. At the same time, this distribution is based on the principle of first come, first served. If the orbital space you need is occupied by other countries, you can only get the allocated satellite orbital space by buying or leasing, or you can only choose the second orbital space.

For example, the basic 24 satellites of GPS in the United States include 6 orbits, and each orbit has 4 satellites, realizing global GPS all-weather coverage; China has 35 Beidou navigation satellites. One of the reasons is that some near-earth orbits needed by positioning satellites are occupied by positioning satellites from other countries. We can only choose higher orbits, so we need more satellites to achieve global all-weather positioning.

According to the data of 20 18, 46 1 spacecraft were successfully launched in the world, of which 95% were artificial earth satellites, and the others were cargo ships and space probes. In recent years, countries have strengthened space exploration activities, especially the maturity of multi-satellite technology with one arrow, and the number of artificial earth satellites has also increased dramatically.

The space is so big that you can launch satellites at will without collision. Because the satellite orbit must be calculated before launch, the orbit of each satellite is different.

I think the global greenhouse effect and environmental damage are directly related to the satellites launched by various countries. How good the space environment of the earth was 40 years ago. In the past 40 years, the global level has developed rapidly and the global environment has changed rapidly. My analysis is directly related to the satellites launched in recent decades.

The subject's worry is a bit redundant. If nothing else, let's talk about the cost of this satellite, which is a lot of money, not to mention the subsequent launch, management and maintenance, operation and maintenance, etc.

With such a large sum of money, how can you be willing to let someone else's satellite crash?

1957 After the Soviet Union sent the first man-made satellite into space, the space for human activities was no longer confined to the atmosphere, but moved towards a new space. Since then, after more than 60 years of development, satellites launched by humans have begun to serve our daily lives, not just in the military and scientific research fields. Such as navigation, satellite TV, wireless communication and other fields on which human beings depend, satellites no longer play a role all the time.

Former US President Kennedy, who took the lead in launching a space race with the Soviet Union, left a famous saying: "Whoever controls the universe will control the earth; Whoever controls space will control the initiative of war. "

Trump, the current president of the United States, established the Space Force during his term of office, and said in a speech that his national space strategy "recognizes that space, like land, sky and ocean, is a field that will fight."

If space is a battlefield, then satellites are the outposts and bunkers of this battlefield.

Since it is such an important field, the management, maintenance and use of satellites have long formed a set of perfect institutional guarantees.

First of all, who manages the satellite.

We know that the cost of developing and launching artificial satellites is very high, and no commercial company can afford this cost, so launching artificial satellites is often a national act. (Of course, spaceX Liquid, a private space company founded by Musk, now has the ability to launch satellites. Moreover, all countries capable of launching satellites into orbit have relevant institutions to manage them accordingly. For example, the National Aeronautics and Space Administration (NASA) of the United States, commonly known as NASA, is responsible for managing all spacecraft launched from American territory, including artificial satellites. Satellite launches in Western European countries are basically controlled by the European Space Agency (ESA). After all, western European countries have a relatively small land area, and it is difficult to find a suitable satellite launch base. Due to the relatively low launch cost, Russia has been responsible for the transportation of the International Space Station all the year round in recent years. Russia's National Space Management Center is in RKA. Of course, the governing body of China is China National Space Administration.

Secondly, how do these institutions manage the normal operation of satellites?

Generally, national space agencies should submit the general road map of satellite and rocket flight to the relevant international organizations in advance before launching the launch vehicle, so as to avoid the problem of how to investigate the responsibility after accidents and accidents. After the satellite is put into orbit, the daily work of these institutions is to operate the satellite to carry out a series of scientific research, people's livelihood and other related research and system maintenance and debugging. The work looks boring, but a little carelessness will lead to great disaster.

Finally, whether the ground station needs to upgrade or replace the equipment.

Generally speaking, replacing new equipment is the daily work that general institutions should complete. However, the ground facilities of the satellite cannot be easily replaced. The monitoring and operation facilities of artificial satellites can basically be said to be dedicated to special planes. If you change it at will, nothing will happen. Once there is a problem, the consequences will be billions of losses. Therefore, whether it is hardware or software, the ground facilities of the satellite cannot be upgraded at will.