If there are many satellites orbiting earth, how do space launches not bump into any of them?
In: 2066
Additionally the radius of where the satellites are vs the cars is greater so there’s even more surface area for satellites to exist
Think about how many Ants are on planet earth: twenty quadrillion. How are you not crushing hundreds of them with every step you take? Because they are tiny and the Earth is *massive*.
The orbit around earth is even bigger than earth, has 3 dimensions to spread out in, and there are only 7700 satellites.
The easiest comparison is that there is about one satellite per state in the US.
Except they’re in multiple orbits of different height, so really it’s like one satellite per country in the world.
Just to give a sense of scale.
If you were to spread out equally not just all satellites, but ALL space debris in general in orbit, each piece would still be hundreds of miles form any other piece.
Add to that, they are not orbiting at the same height from Earth. In fact MOST of them are not orbiting at the same height. So they are actually much farther away than even hundreds of miles (on average). The chances for random collisions even if they were not being tracked at all would be very small.
Imagine there were 10,000 people standing on the Earth, spaced more or less evenly apart. There would be hundreds of miles between each person, standing in what is essentially a 1’x1′ square. Now drop a telephone pole from Space, and what are your chances of it hitting one of those people?
Chances are very low, because the people are so small, and the space between them is so very large.
There are fewer than 10,000 satellites in orbit, and the “sphere” of their orbits is much larger than the surface of the Earth, so the chance of a rocket launch hitting one of those satellites is even lower than the chances of our pretend telephone pole hitting a person standing on Earth.
Another factor is the altitude at which satellites orbit. There are many satellites that orbit at VERY high altitudes around the Earth, above the paths of many rocket launches. For instance, the ISS is only 400 km up, where many satellites will be orbiting 1,000-10,000 km above the Earth’s surface.
Also, all the satellites in orbit are tracked and their position at a certain time is very predictable.
Take a few hundred cars then build a 100 mile tall parkade the size of texas, then tell everyone to drive in a straight line at a fixed speed. Put a gps tracker in each car and when it looks like 2 cars will collide in the future tell one driver to slightly turn left by 0.1 degrees or to go to another level. That’s the size of space
Think about the surface of the planet. All of the objects on just the surface of Earth. Now, imagine expanding out the surface like an inflating balloon into space.
The surface of your “balloon” is the amount of space you have to put things into orbit at a single altitude. Everything up there is actively tracked and the orbits are constant, so if you want to put something else up there you can just check if your orbit will intersect with something else’s.
Want some more room? Expand out the balloon a little bigger or smaller (changing altitude) and start putting stuff there, too.
There is a ton of room up there, much more than the surface of the planet, and we have a lot more than a few thousand objects on the surface.
Go run outside in a straight line for about 10 minutes. Just keep running. How many people will you literally bump into during your little run? Sure, you can put on a blindfold to make it interesting. Yes, it is more likely to bump into people in Times Square than the middle of Kansas. But Times Square is TINY. Remember going for that “really long and boring” drive last year? There were far more open fields and forests than cities. All those areas are places you could easily run around with a blindfold for 10 minutes without being anywhere near another person. Let alone actually bump into that person.
You imagined the difficulty you would have bumping into just 1 person out of 8 billion who are (nearly) all stuck on some pieces of land. The oceans are more than 2.5 times the size of all of that land that holds all of those people. So imagine how much harder it would be to bump into a person if there was no ocean and people could spread out even more!
You are 1 of 8 BILLION people on this planet. There are about 0.25 billion pieces of space stuff in orbit. People are FAR larger than 10 cm (3.9 in) and there are barely 0.0034 billion pieces of space stuff larger than 10 cm (3.9 in) in orbit. Also, those 8 billion people aren’t really at different altitudes, but the space junk is scattered at many different altitudes.
Humans are able to track the most dangerous space debris, so it is more like looking through a dirty window than a blindfold. Yes, it is possible for a collision. No, I’m not worried about a rocket hitting any of them during the 10 minutes it takes to get to orbit.
For more reading: https://www.nasa.gov/mission_pages/station/news/orbital_debris.html
Let’s use a thought exercise. There are an estimated 3.5 trillion fish in the ocean. How do people who jump off boats into the water not smash into a bunch of fish? Because the ocean is huge. And deep. Despite so many fish they arent everywhere and you have to actually try to find them. In comparison there are something like only 7,000 to 8,000 satellites and space around the earth is much much bigger and much “deeper” than the ocean.
For many satellites, the largest part is the solar panels. The US produces about the area of a tennis court annually for space applications. The rest of the world roughly matches us. So the current total area of annually launched spacecraft is less than about 4 tennis courts. We have been launching satellites since about 1960, so just over 60 years. At most we have put up 240 tennis courts worth of area into space. Much of that has burned back in, so you can safely assume that there is no more than say 150 tennis courts worth of material in orbit. That is less than the size of a freeway inside the loop of any moderate sized city. Your odds of randomly hitting man-made space material when just flying into deep space are virtually zero.
The problem with space junk is there are some orbits that are highly used for some particular applications, junk in those orbits, or crossing those orbits will cause problems.
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