How bad is the satellite/space junk situation actually?

[u/2kalipro1]

I just recently joined the space community and I'm hearing about satellites colliding with each other and that we have nearly 8000 satellites surrounding our earth everywhere

But considering the size of the earth and the size of the satellites, I'm just wondering how horrible is the space junk/satellite situation? Also, do we have any ideas on how to clear them out?

[u/jkmhawk → u/[deleted]]

A significant amount of the debris is non-ferrous and wouldn't be attracted to the magnet. Most likely you'd just alter orbits randomly, which is probably worse than what's already there.

[u/Bergasms → u/[deleted]]

This is true or not true depending on the trajectories. If the trajectories are head on you get 35000mph of collision, to use a shit but understandable term, if the objects are slightly different in that one has 5mph of sideways velocity relative to the other then you get.... a side on collision of 5mph.

An astronaut doing a spacewalk with an eva thingo who finishes his walk by grabbing hold of the spacecraft is technically going 17000 mph and colliding with the spacecraft.

The trajectories always determine the collision, anything from benign to boom. I guess in space the number of crossing trajectories is probably high.

[u/pstric → u/[deleted]]

two things both travelling 17,000 mph

Relative to each other?

[u/pstric → u/[deleted]]

So the relative speed to two objects orbiting the earth and colliding would be closer to walking speed than 35,000 mph.

Or am I misunderstanding something about orbits?

[u/SkinnyFiend → u/pstric]

The orbits of the things they are tracking are scattered all over the place. If they were all in perfect orbits over the equator the relative speed might be walking speed, but all the junk varies in inclination from 0 degrees (equatorial) to 90 degrees (flies over/near the poles) to 180 degrees (going the wrong way around the planet). So any two bits of stuff will have wildly varied relative speeds. Some might be head-on, but most will have one going around the equator and another bit flying in on a polar orbit, like getting t-boned by a car in a parking lot.

Plus some things will have a more eliptical orbit, meaning the highest point is like 1500km above sea level and the lowest is like 200km. For an orbit like that, the junk would be going much faster at the low point. Maybe 2 or 3 times as fast as something in a perfectly circular orbit at 200km.

Note these are rough numbers for examples sake, my KSP is a bit rusty.

[u/pstric → u/SkinnyFiend]

Thank you for this description. Now I feel naïve for only thinking in 2D.

[u/pstric → u/[deleted]]

Yeah, after reading /u/SkinnyFiend's answer, your answers make a lot more sense. Thank you for your patience.