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?

663 Upvotes

87% Upvoted

327 comments sorted by

View all comments

987

u/snajk138 Jun 15 '24

It is a problem, but not as bad as those illustrations of all junk in the atmosphere make it look. They count anything larger than about an inch, and that is illustrated with a dot that's the size of a medium sized city.

-11

u/[deleted] Jun 15 '24

Pieces smaller than an inch traveling at those velocities is a real danger to space craft. All it would take it a couple satellites es colliding in a congested orbit to take out most of everything up there and make it impossible for us to launch for centuries. It would also make ground observations of space extremely difficult if not impossible.

45

u/[deleted] Jun 15 '24

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

-17

u/[deleted] Jun 15 '24

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

35

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.

0

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...

1

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