Recently, the head of the European Space Agency, Joseph Ashbach, warned and accused SpaceX's starlink satellites: SpaceX launched thousands of "starlink" communication satellites, which will inevitably lead to a reduction in the radio waves and low-Earth orbit space available to competitors.
He believes that Musk's SpaceX company "sets the rules" in the commercial space field, crowding out other potential competitors and violating the international conventions of "no sovereignty in space" and "no monopoly in space".
Musk responded in an interview last Wednesday: "The Earth's space orbit is very large, and the satellites are very small, and the space resources are almost infinite." A few thousand satellites is nothing. It's like having thousands of cars on the planet, and that's no big deal. ”
This kind of sneaky concept is blatantly said!
It is true that the larger the radius of the sphere, the larger the surface area, so the area of low-altitude orbit must exceed the entire area of the Earth, and it is not a problem to accommodate tens of billions of satellites.
It's like putting 5,000 cars in a parking lot, but what if they all move?
And anyone who has driven a car knows that the front and rear cars must maintain a safe distance before. Usually it is enough to keep 10 meters per hour below 20 kilometers, and it is almost enough to keep 60 meters at 60 kilometers, but it takes 150 meters to 200 meters to keep 100 kilometers. Because the braking difficulty rises too quickly.
The Earth may house the number of satellites
The speed of the satellite around the earth is 28440 km / h, even if it is calculated according to the safe distance of ordinary cars - 100 km and 200 meters, the safe distance between the two satellites is at least 56880 meters.
The radius of the earth is 6371 kilometers, the satellite orbit takes an intermediate height of 1000 kilometers, according to the circumference formula, the circumference = pi× radius ×2, almost the satellite orbit around the earth is 46289 kilometers, so that almost an orbit can accommodate 814 satellites.
The next step is to estimate how many orbits can be made on Earth, and in fact the cross-sectional area of the available orbit of the satellite is almost the area of the satellite's high orbit minus the area of the satellite's ground orbit. A rough calculation can be obtained that the usable cross-sectional area of the satellite is about 432263292.18 square kilometers.
Considering that the satellite needs to maintain a safe distance in all directions, it can be calculated as a square of 3.14 * 56.88 kilometers, and the cross-section of the satellite orbit is almost 10130.39 square kilometers.
Divide the cross-section of the satellite's usable orbit by the cross-section of the satellite's orbit, and divide by 2 because it is 213833 a circular area.
Multiplying the orbit and the maximum number of satellites that can be accommodated in each orbit, it can be concluded that the Earth can theoretically accommodate 174 million satellites.
It seems like a lot, but don't forget that satellites don't steer and brake in seconds like cars.
According to jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, it takes hours for the current space satellite to adjust its orbit once.
Therefore, it is impossible for the earth to accommodate satellites to reach theoretical values, and it is conservatively estimated that it can accommodate 10 million satellites, even if human beings manage it well. Coupled with the fact that once the satellite is damaged, a pile of space junk pops up, and a lot of orbital resources can be wasted in an instant.
There is currently no space garbage recycling technology, which means that the current orbital resources are non-renewable resources.
summary
What used to be a lot of love for Musk now finds that the face of a capitalist has reappeared, a commercial company that sets rules in order to be able to make the space field. A large number of Starlink satellites were launched to seize the common resources of mankind.
If I remember correctly, the Chinese space station has twice urgently avoided the news of the "Starlink" satellite, and Musk can even shamelessly say that the Starlink satellite does not occupy the Earth's orbit too much.