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New Calculation Finds we are close to the Kessler Syndrome [video]

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Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#141

Post by maxglute »

MrBuddyCasino wrote: post #133
maxglute wrote: post #38

Earlier quoted context omitted.

I think OP is suggesting US concede to sharing 500km orbits that SpaceX has disproportionately squatted rights to, since current international law is first come first serve. Where concede is to rejigger international law to increase density of 500km so others wouldn't have to go higher, i.e. PRC mega constellations going ~800 because ~500 mostly taken. Or in ops suggestion, free for all. This is more costly for US si…

There is no such thing as international law. There are only voluntary agreements.

Sure, issue is, if OP math checks out, currently everyone already voluntarily agrees to international law - ITU coordinating LEO orbits that extends to 2000km, meaning hard to clean >400km orbits is going to be filled with 100,000+ megaconstation hardware in next decades, substantially increasing chance of kessler. Op propose limiting >400km orbits... which means US is going to be unhappy sharing space with PRC megaconstellations. PRC not going to accept limiting >400km orbits without openning more <400km orbits because it means ceding advantage to US who locked in high% of <400km orbits since US grabbed megaconstellation spots earlier. So either everyone shares / free for alls <400km orbits, or everyone suffers Kessler, in which case whoever has the most space hardware might end up losing the most.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#142

Post by ryankshaw »

Retric wrote: post #109
throwaway888889 wrote: post #107

Earlier quoted context omitted.

How can you get past that orbit if there is all this junk destroying your rockets????

Ideally a satellite is in a given orbit for years. If junk is destroying it in weeks or even months you’ve got a massive issue. However a rocket is spending in a seconds in that same orbit. Thus a rocket passing through may only have say 1:10,000 odds of a collision on its way to mars while satellites are getting shredded.

Thanks for the explanation.

So you don’t think the 1:10k odds compounded over every space launch are enough to be a problem?

I was thinking that maybe as you get to a scale where you have things coming and going all the time, and each time they have to pass through the debris layer, and if they have bad luck they become part of that debris, that eventually you get to a point where even just passing through that layer is untenable. But you don’t think that is likely even for a society sending out interplanetary vessels every day?

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#143

Post by [deleted] »

lxgr wrote: post #140
PittleyDunkin wrote: post #130

Earlier quoted context omitted.

Good luck dragging people into war over space trash that doesn't even benefit most peoples' lives in any material sense.

Are you sure that you have never looked at a weather forecast (or received a severe weather warning), crossed an ocean in an airplane, used GPS (or another satellite-based navigation system, or eaten food farmed using precision automated equipment that does), which are just the first things coming to mind that would be much harder without satellites?

[deleted]

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#144

Post by Retric »

ryankshaw wrote: post #142
Retric wrote: post #109

Earlier quoted context omitted.

Ideally a satellite is in a given orbit for years. If junk is destroying it in weeks or even months you’ve got a massive issue. However a rocket is spending in a seconds in that same orbit. Thus a rocket passing through may only have say 1:10,000 odds of a collision on its way to mars while satellites are getting shredded.

Thanks for the explanation. So you don’t think the 1:10k odds compounded over every space launch are enough to be a problem? I was thinking that maybe as you get to a scale where you have things coming and going all the time, and each time they have to pass through the debris layer, and if they have bad luck they become part of that debris, that eventually you get to a point where even just passing through that layer…

A problem, but not an insurmountable one.

Being hit isn’t the same as being destroyed, you can track and avoid large objects, and small are survivable in the short term. https://en.wikipedia.org/wiki/Whipple_shield Collisions however keep adding up until a satellite fails.

Second an outbound rocket need not be in orbit, so if it is destroyed that may not result in extra orbital debris the overwhelming majority of mass could fall back to earth.

Also, Kessler syndrome isn’t a forever thing. There’s a reason planets have rings not debris clouds. It’s possible to have a steady state where the rate you’re making it worse is balanced with the rate things are naturally clearing.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#145

Post by schiffern »

MichaelZuo wrote: post #131
PittleyDunkin wrote: post #127

Earlier quoted context omitted.

> We need viable treaties limiting development beyond 400 or 500km and we need them ten years ago. Basically every other interest on earth is going to see this as the west exploiting space then pulling the ladder up after them. It's the same reason why hoping developing countries will stop using coal is ridiculous. We need to foot the bill to clean up after ourselves or people will just ignore us and do what they see…

Yeah unless all the orbits under 500 km are also annulled and put up for negotiation too, most countries would never accept it. And even then the negotiation process will take decades so that means no LEO satellites available for anyone for several decades.

  > all the orbits under 500 km are also annulled and put up for negotiation
Unnecessary. There's plenty of space (no pun intended) to operate at those altitudes, even with existing and planned satellite constellations.

The real issue is regulatory, not technical. See https://news.ycombinator.com/item?id=42199498

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#146

Post by schiffern »

JumpCrisscross wrote: post #63
mapt wrote: post #57

Earlier quoted context omitted.

If 800km impacts go asymptotic, it pollutes 700km and 900km orbits by virtue of having a distribution of resulting debris velocity vectors, and as drag pulls down all the resulting debris over the next thousand years, the 800km debris becomes circular 700km debris, and then circular 600km debris, and then circular 500km debris.

> as drag pulls down all the resulting debris over the next thousand years, the 800km debris becomes circular 700km debris, and then circular 600km debris, and then circular 500km debris Circularisation isn’t the unexpected part. Sphericalisation is. One requires orbits to desync. The other requires plane changes.

  > plane change
If you watch the animations in this (excellent) ESA video, you see the plane change occurs rapidly all by itself. Over the course of a few months it covers the entire globe, spreading across all "latitudes" (aka RAANs).

Roughly 3 minutes in: https://www.youtube.com/watch?v=9cd0-4qOvb0

https://en.wikipedia.org/wiki/Nodal_precession

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#147

Post by mapt »

perihelions wrote: post #116
m4rtink wrote: post #111

Earlier quoted context omitted.

I think it would be actually the other way around - Starlink orbits aee low enough to be self cleaning & Starlink satellites can be (and are) rapidly replenished. So even if something from up above hits anfew, the debris would deorbit soon & new ones could be launched. With GEO sats, unless you go for direct GEO insertion, it might still have issues reaching the final orbit. And even at GEO, there could be a debris c…

- "And even at GEO, there could be a debris cloud as well causing issues, at least until the sun and moon gravity perturbs it enough." Not a satellite expert, but I understand GEO clears out relatively fast (~decades), because of those 3-body perturbations, https://www.agi.com/blog/2020/07/geo-satellites-don-t-decay-...

Your link talks about how this is an unexpected result, and only occurs at specific inclinations.

It's new information to me, though. Thank you.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#148

Post by mapt »

Cthulhu_ wrote: post #122
fragmede wrote: post #100

Earlier quoted context omitted.

> if even achievable with current technology Launching a nail bomb into orbit would've been possible as soon as we were able to get into space, the only question is motivation. A terrorist state, say North Korea, threaten the rest of the planet and demand concessions once they're able to get any significant mass into orbit.

I'd say intentionally destroying space assets etc should be considered an act of war (compare attacking another nation's ship in international waters), NK wouldn't have a chance and they could be put into space lockdown where any launches are intercepted.

It is even worse than the analogy, because every bit of mass from that sunken ship becomes drifting naval mines.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#149

Post by mapt »

m4rtink wrote: post #111
lxgr wrote: post #65

Earlier quoted context omitted.

I'd consider it much less likely than e.g. nuclear or maybe chemical/biological warfare. Kessler syndrome (if even achievable with current technology) would be a major bummer for science and the global economy for a couple of decades (no more Starlink, but we still have good old geostationary satellites, so no ships and airplanes would get disconnected as a result), or at worst centuries, but would otherwise not form…

I think it would be actually the other way around - Starlink orbits aee low enough to be self cleaning & Starlink satellites can be (and are) rapidly replenished. So even if something from up above hits anfew, the debris would deorbit soon & new ones could be launched. With GEO sats, unless you go for direct GEO insertion, it might still have issues reaching the final orbit. And even at GEO, there could be a debris c…

The approximate-GEO belt involves far fewer satellites than projected megaconstellations, in a far larger volume of space, travelling at far lower orbital velocities, with a much tighter orbital plane distribution (so even lower relative velocities). Their orbital planes intersect every 12 hours instead of every 0.75 hours.

Targeted space junk disposal in GSOs appears to be quite practical. The easiest major orbital changes for an SEP stage to burn, structurally, involve lowering periapsis from high orbit.

Re: New Calculation Finds we are close to the Kessler Syndrome [video]

#150

Post by resters »

bagels wrote: post #86
resters wrote: post #18

Positioning a large, armored satellite in low or mid-Earth orbit significantly enhances its strategic value for both offensive and defensive anti-satellite operations. Such a platform could serve as a pivotal asset in maintaining orbital dominance, offering rapid response capabilities to neutralize threats and protect critical infrastructure. In other words, welcome various "death stars" to keep order against malicio…

"armored" I don't get the impression that you've looked at the physics of orbits. Everything up there carries tremendous kinetic energy. It would be pretty hard to build something strong enough to take on intentional collisions, let alone large debris. Fun reading: https://www.esa.int/Space_Safety/Space_Debris/Hypervelocity_... Here's a picture to illustrate: https://www.esa.int/var/esa/storage/images/esa_multimedia/…

Those are interesting resources! I meant armored in more of a figurative sense, as in "prepared to defend itself against offensive collisions".
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