Space is big, unbelievably big.
Low earth orbit is roughly 200 km to 800 km in altitude.
GPS satellites are at about 20,000 km in altitude.
Geostationary orbit is 35,000 km up.
The international space station is at roughly 420km altitude, travels at 27,600 km/h, yet takes 93 minutes to orbit the earth once.
Space is just big.
I’m addition, we track objects in orbit, this site says we track over 45,000 items larger than 10cm in size (satellites, rocket parts, debris, the ISS), with there being over a million larger than a centimetre (flecks of paint, lumps of rock/ice, small bits of debris etc). Satellites often have to move to avoid known debris (example for the ISS) and have outer shells that can absorb/disperse smaller impacts (the ISS has armour!)
The biggest causes of debris has been countries testing out anti satellite missiles. Even small bits of debris, a fleck of paint etc can do a lot of damage when the closing speed is 10s of thousands km/h!
Source for most numbers
Edit: fixed spelling and lower bound of LEO
The extra protection on things like the ISS is for more than just man made debris. The Earth is a big gravity well, constantly pulling in and running into things in space. That’s what meteors are, usually small specks of rocks, and the Earth’s atmosphere is like a windshield being driven in rain or snow (or bugs, but that doesn’t happen as much anymore :( ).
There’s around 15 000 satellites in orbit. Imagine there was only 15K cars on earth, and they could drive everywhere at random. How long do you think it would be before you even saw one, let alone there was a collision. Now imagine the area is much bigger, has an extra spacial dimension, and is being tracked and controlled.
Edit. There is, on average, a similar number of planes in the air as satellites, and mid-air collisions are extremely rare and usually only happen at choke-points like airports.
Planes are a good analogy. Pull up any flight tracker map, and zoomed out it’s like the sky is full of planes. How can they miss each other? But then you zoom into a scale that makes more sense, and realize that usually there’s lots of room in three dimensions between them all, with ones going different directions being at different altitudes to be able to cross paths when they do.
Its going to become an issue the more crap we throw into space for commercial reasons. All the satellites are ruining the ozone too.
Because rockets are scheduled to avoid collisions and the ISS has manoeuvring thrusters to slowly get out of the way of space junk. The US Space Force and national space agencies (NASA, ESA, etc) track what’s up there and let people know.
I just keep thinking of that picture with earth and it is surrounded by dots suppose to be satelite and space debri. Kind of seems like a hard thing to schedule. Is this why rockets take off at a slight angle instead of straight up and down? Or is it just seem that way from our view point on a rotating mass?
Rockets take off at an angle because they stay up due to horizontal motion, not vertical (once they’re above the atmosphere). Essentially they go so fast that the curved surface of the earth falls away exactly as fast as the rocket falls. If they just went up, they’d come back down at the same speed due to gravity. Gravity affects rockets for way further than you would think (consider that the moon stays where it is in orbit due to gravity).
Rockets need to go fast parallel to Earth surface rather than just high, though atmosphere slows you down, so you start by going up to get where atmosphere is less dense faster and angle yourself steadily to gain orbital speed.
The first two pictures here explain it better than I ever could
In my feed this: https://piefed.social/c/technology/p/2177562/a-new-crash-clock-measures-the-chance-of-satellite-collisions-and-its-ticking-down-fast
was just a few posts down from yours.
Different orbits. For two things to collide in space, orbital height (altitude) has to intersect. And the orbital parameters of anything up there is tightly controlled/regulated as well as monitored.
Even if two objects’ orbits do intersect, the timing has to match as well. Two objects can be on the same orbit, but out of phase with each other.
Plus, the thing about space is just that: There’s an awful lot of it. While it’s easy to imagine that it’s tightly packed, it’s mostly just empty space. On a similar note: Asteroid fields don’t look like they do in Star Wars. You could be in the middle of an asteroid field and see absolutely nothing.
And since this is three dimensional space over a globe, the higher you go, the more room there is.
On top of that, satellites do have some ability to maneuver (change their orbits), so if their orbit has drifted enough to be a concern, they can adjust. Satellites that are supposed to stay up there for a long time that have run out of thruster fuel are placed in junkyard orbits where they won’t cause any harm, and some of the closer ones are deorbited and burn up during reentry.
Tight surveillance, basically
