5 ms·
How many satellites can we put up there before we get one giant game of snooker?
by demondemidi 3y ago
How many satellites can we put up there before we get one giant game of snooker?
- danparsonson 3y agoSeriously. 30,000! They should just go ahead and call it the Kessler Network
- panick21_ 3y agoI never understand why people are so obsessed crying about Starlink and Kessler Syndrome when any rational thought about it instantly suggest that this is practically impossible to happen. Do you also worry Supervolcano anytime anybody digs a hole?
- danparsonson 3y agoOK. Do you have any actual counterargument, or just your sense of disbelief? > Do you also worry Supervolcano anytime anybody digs a hole? No. The risk is not remotely comparable.
- olivermuty 3y agoPut 29 988 people spread out on the globe (slightly larger since we are further out in the radius, but lets ignore that). Do you still wonder? Probably you could put a few million up there before collision is a worry. Space debris and blocking observatories is a much larger problem.
- ceejayoz 3y ago> Put 29 988 people spread out on the globe... ... and then have them run at 17,000 miles per hour.
- bryanlarsen 3y ago... on highly predictable and known paths.
- swarnie 3y agoWhere only a percentage of objects can change their path if needed. If a collision does happen 2 objects become 20,000 objects in an instance.
- bryanlarsen 3y agoIf a 300kg satellite at a 300 mile orbit becomes 20,000 pieces, those are pretty darn small pieces. Objects in space regularly get hit by <1cm micro-meteoroids. They may become disabled but they don't shatter. And by being so small their mass/area ratio becomes really small and they deorbit within 90 minutes from that altitude.
- ceejayoz 3y agoThe orbital tracks at https://en.wikipedia.org/wiki/2009_satellite_collision https://en.wikipedia.org/wiki/2009_satellite_collision clearly show how a high-speed collision can raise the orbits of the resulting debris, having imparted significant acceleration to them. (For example: <https://en.wikipedia.org/wiki/2009_satellite_collision#/media/File:Collision-50a.jpg https://en.wikipedia.org/wiki/2009_satellite_collision#/medi...>) That smash "created at least 1,000 pieces of debris larger than 10 cm (4 in)".
- ceejayoz 3y agohttps://en.wikipedia.org/wiki/Satellite_collision https://en.wikipedia.org/wiki/Satellite_collision lists six unintentional high-speed collisions involving satellites that have already occurred. That's with 2-8k or so in orbit at the time. https://en.wikipedia.org/wiki/2009_satellite_collision https://en.wikipedia.org/wiki/2009_satellite_collision alone made two thousand cataloguable fragments to track on new paths we didn't get to pick.
- 3y ago
- flatline 3y agoThere have been several notable collisions in the last decade. I think a full blown Kessler scenario is unlikely but it will definitely be a problem for satellite operators. Let alone the impacts on terrestrial astronomy.
- Keyframe 3y agoare orbits (LEO, MEO, GEO) path-specific, like lanes, or it's willy-nilly where only altitude is mandatory-ish?
- polonbike 3y agoYou mean a Kessler syndrome, or event https://en.wikipedia.org/wiki/Kessler_syndrome https://en.wikipedia.org/wiki/Kessler_syndrome And to answer your question : we don't know exactly yet, but I guess we'll know pretty soon
- mcpackieh 3y ago> Kessler syndrome soon No, certainly not in LEO. Debris in LEO falls back to Earth in only a few years so even if a shooting war started and shattered every satellite in LEO into a mist of deadly orbital speed bullets, a few years after the war ends LEO would be clear again. All of the other effects of such a large-scale shooting war would be far more concerning to everybody on the ground, space debris would be the least of the concerns for any survivors.
- bryanlarsen 3y agoIf we give each a cubic kilometre keep-out zone, then we can put up 500 billion between 300 and 1300 kilometre altitude. A cubic kilometre keep out zone is pretty generous, we could probably put in trillions if needed.
- demondemidi 3y agoHow do you keep each satellite in its own cubic kilometer? How do you know that is "pretty generous"? Why not .5cukm or 2cukm?
- rob74 3y agoIf all those satellites were static instead of zipping around at several tens of thousands of miles per hour, that would work out...
- panick21_ 3y agoExcept sats have a very predictable path so its not actually that difficult, stationary or not. The system of airplane management is 1000x more complex.
- dreamcompiler 3y agoSatellite paths are only predictable in the short term. Predicting satellite paths beyond about a week is not possible unless you're comfortable with huge amounts of uncertainty. Newtonian physics says that ideal two-body problems are predictable to any point in the future. But ideal two-body problems exist nowhere in the universe, especially in near-earth orbit.
- mcpackieh 3y agoGood thing we have radar.
- twic 3y agoIf you actually know about this stuff, i would be very interested to hear the reasoning behind a cubic kilometre being a generous keep-out zone (and cubic kilometres even being a sensible unit for a keep-out zone). Since this is HN, my guess is you don't, but i would love to be wrong for once.
- tomxor 3y ago"Snooker" would be so much simpler, unfortunately it just turns into super high speed shrapnel.