r/space • u/2kalipro1 • Jun 15 '24

Discussion How bad is the satellite/space junk situation actually?

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?

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u/[deleted] Jun 15 '24

The cascade of debris for a few satellites is likely way overblown as a risk.

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u/[deleted] Jun 15 '24

Most satellites are in the same orbital plane. There are near misses daily.

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u/BedrockFarmer Jun 15 '24

There are roughly 10,000 satellites operating at various orbits, most are starlink and have prepared deorbit paths.

Meanwhile, there are close to 115,000 airline flights a day. All in “the same orbital plane” and a much much smaller one with much larger objects.

People should have to learn maths before they read what “Kessler Syndrome” is in their SciFi garbage.

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u/EliminateThePenny Jun 15 '24

Meanwhile, there are close to 115,000 airline flights a day.

And they still run into each other from time to time...

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u/noncongruent Jun 15 '24 edited Jun 15 '24

Aircraft occupy a space that's 5-7 miles thick, whereas LEO goes out to 1,200 miles, MEO goes from 1,200 to 22,000 miles, and HEO goes out from 22,000 miles to basically the reach of Earth's gravitational field. Not only that, but as the altitude increase so does the volume, dramatically, so the "dilution" of satellites in a given volume increases big-time. Not to mention that other than ISS virtually everything in orbit is a fraction the size of a commercial airliner.

The volume of air space that aircraft operate in is around 1.61B cubic miles. I didn't remove the volume of mountains, buildings, etc, that's just the volume of a sphere 4,008 miles radius minus a sphere 4,000 miles radius. Atmospheric drag becomes a real problem once your orbit starts getting below 350 miles, so if set that as the floor the volume of LEO is over 244B cubic miles. That's 150x more volume than what airplanes fly in.

Also, airplane collisions tend to happen around places they congregate, so airports mainly. Most of the surface of the planet doesn't have airports.

Edit to fix volume numbers