The current trajectory is that SpaceX proved the commercial and military viability of an LEO megaconstellation, repeatedly lowering their target altitudes and raising their satellite count because of debris and cell size concerns...
And now the rest of the world is trying to catch up in a sort of arms race, and not taking any care about debris concerns. The most tempting orbits are the ones in upper LEO that permit them to launch fewer satellites.
SpaceX are going to end up well under 500km (orbital lifespan: a decade) before things are finished, and they switched to very low orbit staging with SEP spiral out to reach final orbit a ways back.
China's newest constellation Thousand Sails is at an altitude of 800km (orbital lifespan: thousands of years), with a thousand satellites in the works over the next year or so and 14,000 planned, and they're launching them using chemical upper stages designed to explode into a thousand pieces at the target altitude. This is sufficient for Kessler Syndrome all on its own, without counting interactions with anything else up there. A catastropic debris cascade at 800km percolates down to lower altitudes over time and impacts.
We need viable treaties limiting development beyond 400 or 500km and we need them ten years ago.
I don't know how to sell the urgency of this predicament. You can have as many satellites as you want, a million uncoordinated bodies, at 400km because direct collision potential scales with (satellite count / orbital lifespan) ^2 . At 1000km, satellites decay so slowly we are already too crowded; we have already overused the space. We are speed-running the end of the space age and we are doing it to save a small number of dollars and to avoid a small amount of diplomacy.
This is not something we get a do-over on. There is no practical way to collect ton-scale debris at present, no way to track kilogram-scale debris, no practical way to shield pressure vessels against gram-scale debris, and even milligram-scale debris can hit with the force of a bullet. After collisions start occurring at a rapid clip, the mass of potential impactors quickly forms a long tailed lognormal distribution that denies us space for centuries.
As in, is it the thing that makes it so no one else has broken out of their planet to come visit us?
I could totally see it being the case that as soon as a civilization gets good enough at putting stuff into space, they start putting a lot of stuff into space and then things start crashing into each other to the point that they can’t ever launch any more things into space and become stuck. Trapped by the artifacts of their own progress
kmeisthax 69 days ago [-]
No. The space junk at a given orbit makes it unviable to put more satellites in that orbit, but launching beyond that orbit is still viable.
throwaway888889 69 days ago [-]
How can you get past that orbit if there is all this junk destroying your rockets????
Retric 69 days ago [-]
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.
ryankshaw 68 days ago [-]
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?
Retric 68 days ago [-]
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.
throwaway888889 68 days ago [-]
Yes exactly ... This is a cloud of junk that stops anything getting out....
the8472 68 days ago [-]
integrate risk over time. if you have a high target orbit outside the "kessler belt" then you don't spend much time going through it. though this requires a fairly direct orbital insertion. slow orbit raising would have a higher risk, but even that would still be lower than for any satellite intended to operate for years and decades in an affected orbit.
Cthulhu_ 68 days ago [-]
It really depends on how much junk actually is there and in what orbits; especially at 500 km up, space is big. The surface area of the earth is 510.100.000 square kilometers, at 500 kilometers the 'surface area' is a multiple of that (I can't math), surely there's enough gaps or lower-density areas at that height even if there was a catastrophic Kessler Syndrome event.
aargh_aargh 68 days ago [-]
The surface area at 500 km is 1.16 of the Earth surface area.
lxgr 69 days ago [-]
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 any threat to civilization, whereas nuclear winter is already very capable of wiping it out.
m4rtink 69 days ago [-]
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 cloud as well causing issues, at least until the sun and moon gravity perturbs it enough.
mapt 68 days ago [-]
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.
lxgr 68 days ago [-]
On the other hand, there is just so much less stuff up there, as reaching that orbit is much more expensive in terms of energy expenditure, and it's all moving in pretty much the same direction and in the same orbital plane.
So unless somebody maliciously launches e.g. a bunch of ball bearings in the same orbital plane but opposite direction, the chances of "wrecking GEO" seem much lower (although the consequences would, as you say, probably be much more severe and long-term).
perihelions 69 days ago [-]
- "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,
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.
fragmede 69 days ago [-]
> 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.
Cthulhu_ 68 days ago [-]
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.
mapt 68 days ago [-]
It is even worse than the analogy, because every bit of mass from that sunken ship becomes drifting naval mines.
PittleyDunkin 68 days ago [-]
Good luck dragging people into war over space trash that doesn't even benefit most peoples' lives in any material sense.
lxgr 68 days ago [-]
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?
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PittleyDunkin 68 days ago [-]
Do you really think people will want to go to war to protect America's hegemony of gps?
lxgr 68 days ago [-]
I believe the US would almost certainly go to war if there were an intentional attack on GPS.
PittleyDunkin 67 days ago [-]
The us goes to war if someone sneezes.
ljsprague 69 days ago [-]
I would guess that it would still be possible to send things beyond earth's orbit with only a low probability of collision with debris but perhaps I'm wrong.
to11mtm 69 days ago [-]
"Low" is tough to say until someone does some proper sort of 'true mapping' of space debris in the range somehow. Protection would require a lot of complexity and cost due to the need for shielding and the delta-v to move it up there.
JumpCrisscross 69 days ago [-]
> until someone does some proper sort of 'true mapping' of space debris in the range somehow
You look at which satellites poofed and then figure out the maximum extent their debris could have drifted.
mapt 69 days ago [-]
That works a little bit when we're talking about one satellite poofing in a year based on a collision with another satellite, and not at all when we're talking about thousands of events a year, many of which are satellite-debris collisions too small to track (you only get one orbital vector), or between pieces of debris.
Every collision generates hundreds, maybe thousands of pieces of debris, only the largest of which are trackable.
JumpCrisscross 69 days ago [-]
Not really. There are uncertainty bands. But based on the collision you know which orbits are spoiled for about how long.
vlovich123 69 days ago [-]
Rather than protection on each rocket, couldn't you just send a bunch of fortified rockets that absorb the debris during a collision but don't emit anything. Do that a few times and then all other rockets just reuse the path that was cut?
mapt 69 days ago [-]
Orbit is not a location. Orbit is a group of velocity-location vectors which form a stable loop around a body, without intersecting that body.
Imagine a bullet circling your head at mach 25. Now imagine a second bullet, circling your head at a slightly different angle, at a slightly different distance from your head. There's a chance that they could collide, and the resulting explosion would leave a great deal of dust... on a mixture of velocities, still circling your head. Now add a third bullet, also on a slightly different vector; Make sure that it doesn't collide with any of that dust!
The actual situation is we aren't dealing with 3 bullets or 100 bullets, we have ~170 million objects orbiting the Earth, and only around 50,000 are large enough to track. They are all moving fast enough in relation to each other that a collision would result in a sizable explosion, not an elastic agglomeration. We have no way of removing them.
The good news is that there is a large volume of space for them to exist in. The bad news is that as we continue to fill it up, odds of collisions increase, and every collision spawns many, many more objects.
vlovich123 69 days ago [-]
You’ve explained what Kessler syndrome is but not why my idea doesn’t work.
I’m saying send reinforced rockets through the orbits that absorb the collision instead of generating more dust. That should let you clear a path through all orbits that intersect your path. It’s hard to do and the 3d aspect of it might make it expensive but conceptually it could be a solution. Or use super powerful lasers (potentially mounted on a satellite) to deorbit the dust
ben_w 69 days ago [-]
> I’m saying send reinforced rockets through the orbits that absorb the collision instead of generating more dust. That should let you clear a path through all orbits that intersect your path.
No such material exists, nor can it be made from any matter that is based on electrons bound around a nucleus — the force of impact will break any such material.
> It’s hard to do and the 3d aspect of it might make it expensive but conceptually it could be a solution.
The cost requirement for getting something to space with enough momentum to do the cleanup, even if it was able to survive the impacts, would be comparable to the entire cost of getting the stuff constituting the mess into orbit in the first place: bad enough to be prohibitive even today with relatively little mess, much worse if there's an actual Kessler cascade.
> Or use super powerful lasers (potentially mounted on a satellite) to deorbit the dust
Could work for the bigger bits, but don't put the lasers on a satellite: 1) Power is short up there, as is cooling, much easier to put a bit laser on the ground and waste some energy going up through the atmosphere; 2) if you solve that constraint, you've now got an orbital laser that's an obvious and easy-to-hit target for all foreign powers to get upset about even if you didn't want to weaponise it.
For the smaller stuff, you can't see the dust to target it in the first place.
mapt 69 days ago [-]
This doesn't work conceptually, but it's hard to explain without attaining a KSP baseline of understanding. https://xkcd.com/1356
"Clearing a path" is something you can do with a bulldozer through a traffic jam, but imagine clearing a path through a belt road by driving through the flow of moving traffic sideways at speed. Ultimately you can't hit every car in the outer lane with just one bulldozer, and the cars will close in and fill gaps because they're moving at slightly different speeds.
The easy elastic collisions you're imagining also just can't occur at these relative velocities. When something hits it looks more like an explosion than a "catch". If you shoot a local stone monument with high explosive artillery shells what happens? Does it reduce the number of things flying through the air or increase it?
immibis 69 days ago [-]
It takes about 90 minutes to complete a low earth orbit. A rocket can't hover in place for 90 minutes at the same altitude, then increase its altitude by its height and repeat. It doesn't have enough fuel for that.
vlovich123 69 days ago [-]
Go the other way. Attain maximum altitude and then descend slowly. You don’t need to do this with just one rocket. This would be a clearing exercise composed of multiple rockets.
LoganDark 69 days ago [-]
This sounds like it would almost work in a 2D universe.
lmm 69 days ago [-]
> couldn't you just send a bunch of fortified rockets that absorb the debris during a collision but don't emit anything.
"Just" how? Orbital collisions happen at an average of 10km/s, you're going to make what, some kind of sponge that can get hit by a chunk of satellite going ~8x faster than a bullet and absorb it and slow it to a halt without fragmenting at all? Good luck.
> Do that a few times and then all other rockets just reuse the path that was cut?
Things in orbit are constantly moving, you can't "clear a path" any more than you can, IDK, make a safe route through a forest by walking through it once and moving any bears you encounter a couple of feet.
lupusreal 69 days ago [-]
A large mass of Whipple shields.
The "clearing a path" idea is inane, but we do know how to absorb hypervelocity debris impacts while generating a net negative amount of debris.
ben_w 68 days ago [-]
Whipple shields fragment, don't they? They slow stuff down enough to not be a hazard to the thing being shielded, but if the goal is mess-reduction I don't see how that will help?
The force of the impact effectively vaporizes part of the shield and the debris. Eventually the shield will be structurally unstable swiss cheese, but that can be modeled and the shield deorbited before it starts to fall apart.
RHSman2 69 days ago [-]
I love this retort. Made my day.
0x1ceb00da 69 days ago [-]
Every launch failure will result in more debris and even lower probability of a successful future launch.
JumpCrisscross 69 days ago [-]
> don't know how to sell the urgency of this predicament
We need to start by understanding it. I'm having trouble finding this paper right now. But to date, all calculations have shown that Kessler syndrome as a generalised phenomenon is incredibly hard to trigger. Even intentionally. Especially in LEO. (Intentionally triggering it is of interest for strategic ASAT denial.)
> the mass of potential impactors quickly forms a long tailed lognormal distribution that denies us space for centuries
No, it denies certain orbits. (Again, barring some new orbital dynamic haven been discovered by this paper.)
mapt 69 days ago [-]
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.
JumpCrisscross 69 days ago [-]
> 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.
schiffern 68 days ago [-]
> 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).
Even in a purely planar distribution, nodal precession still occurs slowly.
It doesn't even need to be factored in, though, if different planes are colliding with each other and energetically generating a spectrum of new orbital vectors (many less than circular) from impact. This effect colludes with altitude drop from orbital decay and the tendency to circularize orbits by perigee drag, to make it so that higher orbit debris percolate into lower orbits over time.
wbl 69 days ago [-]
There is percession of the perigee.
PittleyDunkin 68 days ago [-]
> 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 they need to do regardless.
MichaelZuo 68 days ago [-]
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.
schiffern 68 days ago [-]
> 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.
An HN user’s opinion doesn’t matter in the context of how countries decide in international diplomacy…?
How does this make sense? Other countries could clearly decide however they like, because they don’t need to come to the negotiating table.
schiffern 67 days ago [-]
It's not my opinion. The ITU permitting system described in my link is the (negotiated) international system that exists today. If you're suggesting it might be re-negotiated to allow latecomers to build constellations below 500 km, then we agree.
However your idea of "annulling" permits already given out isn't necessary, or politically feasible, or even desirable.
"Annulling" is just one HN user's jealous destruction fantasy.
MichaelZuo 65 days ago [-]
Are you confusing me with someone else, or have you gone deranged?
I was the one who implied the status quo, i.e. countries putting things into orbit way above 500km and nobody stopping them, is likely to prevail… with even the next best alternative very unlikely to happen.
bamboozled 69 days ago [-]
One way is for the the US to be more politically stable again (some how). Every country with an army will want its own star link now for trust reasons.
mapt 69 days ago [-]
For how long?
Because this thing is happening right now, it's happening fast, and it's happening without any effort to fight against the trend.
If your answer is "let's revisit this in 2050", then it isn't an answer.
immibis 69 days ago [-]
And it will continue to happen and nothing can be done about it. Except global nuclear war, I suppose. That's not off the table.
bamboozled 69 days ago [-]
Yeah well it means a lot of satellites are going to end up in space then.
nradov 69 days ago [-]
The US is politically stable already (by historical and international standards), and has been since 1865. If you ignore the rhetoric and focus on actions there has been very little substantiative difference in foreign policy across the last 7 presidential administrations.
dangerwill 69 days ago [-]
The US civil war is not the only time the US has been politically unstable. The civil rights movement, the labor disputes of the 1970s, the economic shocks every decade or so from market crashes all have been moments of instability.
What is January 6th if not a concrete example of recent political instability?
As for foreign policy consistency, 7 administrations takes us back to Reagan... The entire movement to sell out our industrial capacity to China and now the movement to try to reverse that have occurred in this time frame. This is just as important as our endless wars in the middle east, imo.
I don't disagree totally but I felt the need to put some nuance here.
nradov 69 days ago [-]
Stability doesn't mean statis. The USA has been remarkably resilient to those minor shocks you listed. It continues to be the most politically stable of all the countries that actually count for anything in international affairs.
dangerwill 68 days ago [-]
If those are "minor" shocks then is it only outright war that counts as instability for you?
If so then what countries in Europe (sans the Balkans) or East Asia do you think are less politically stable than the US?
lucianbr 69 days ago [-]
If some catastrophic event is required to define instability, then by definition any country will be stable right until one second before catastrophe. This may work fine for certain analyses, but for predicting if or when that event may happen it is useless.
You're saying "nothing bad will happen because nothing bad has happened so far". There's a first time for everything.
lmm 69 days ago [-]
Going from a treaty and cooperation with Iran to cutting them off was a pretty substantial change that has already had global implications.
no_exit 68 days ago [-]
Even prior to that, Iran was desperately trying to cultivate relations with the West in the 90s/00s before Bush suddenly declared them Axis 2.0 and created a massive security crisis on their doorstep.
[1]
> What emerged out of this economic crisis was a reform movement led by Mohammad Khatami, who won a presidential election in 1997 on promises to cultivate civil society, fix the economy, and replace a "clash of civilizations" with a "dialogue of civilizations." The cultural transformation unfolded over the next several years was remarkable. The share of university graduates who were women topped 60 percent, a new generation of intellectuals began to favorably cite Western philosophers, and religion more or less stopped policing the daily lives of most Iranians. By 2000, the Economist was reporting that according to Iran's own clergy, fewer than 2 percent of Iranians attended mosque on Fridays. On the economic side, the neo-liberalization of Iran intensified; small-scale factories were exempted from labor laws, and state-owned industries were privatized (loosening the state's grip on the economy was thought to be the best way of decreasing state interference in Iranians' private lives). Iran's relationship with foreign nations, even the US, also improved considerably. President Clinton eased up on the economic sanctions that Reagan had put in place in 1987, and Khatami appeared on CNN to talk about his admiration for the American nation and people. Al Qaeda's attack on the United States on September 11, 2001, was met with a massive outpouring of sympathy for America in Tehran, with enormous crowds holding candlelit vigils and some sixty thousand people observing a moment of silence at a soccer match on September 23.
If Iran was legitimately interested in having relations with the West then they would allow religious freedom, release political prisoners, introduce free elections, recognize Israel's right to exist, stop sponsoring terrorist organizations, and apologize for holding our diplomats hostage. Since they didn't do any of those basic, simple things then I don't believe for a second that they were "desperately" trying. People who are actually desperate do whatever it takes instead of the bare minimum.
President Bush certainly bungled the situation as well.
immibis 69 days ago [-]
We are currently in a low-trust, selfish world where all hope of collaboration has gone out of the window, so we are on an unchangeable trajectory towards things like Kessler Syndrome and climate hell.
heresie-dabord 69 days ago [-]
> Kessler Syndrome and climate hell
Both of which demonstrate that our species is much better at understanding how to scale madness and destruction than how to scale sustainable activity.
shiroiushi 69 days ago [-]
Humanity is a failed species. The engineers were right to send the xenomorphs.
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perihelions 69 days ago [-]
Why would any of the US' adversaries agree to that? We have SpaceX, and they do not; lowering the altitude of megaconstellations is asymmetrically far more costly for them then it is for us.
Stopping China's (highly strategic, military) satellite constellations isn't a "small amount of diplomacy". It's an impossibility.
(It's even their declared planning that deliberate Kessler cascades are on the table [0]—to try to ground this discussion in diplomatic reality).
Invite them in. Launch their satellites for them, at 400km. Give them cash or territory. Give away the farm. How doesn't matter. What matters is that we start coexisting at 300-500km, and we mutually taboo launching large amounts to altitudes much higher than that.
There is no stable Mutually Assured Destruction Nash equilibrium here, if either of us does this thing it causes dramatic harm to both.
Not regarding that as a worthwhile goal is "mineshaft gap" thinking - a zero-sum mentality entirely ignoring our collective advantage in order to pursue competitive advantage.
It is perfectly feasible to run a Chinese constellation alongside Starlink sharing the same space, orbitally. Very low orbits are self cleaning.
perihelions 69 days ago [-]
Not agreeing with any of this.
- "Launch their satellites for them, at 400km."
No reasonable person would help their adversary build powerful weapons that could immediately be used against them. The point of satellite constellations—Chinese or American, either—is to create undeniable, high-bandwidth communications for armies; to create real-time (as opposed to sporadic) satellite imagery for armies; to create, in short, an overwhelming situational awareness advantage in a conventional war.
- "Give them cash or territory."
We are not giving away countries.
nradov 69 days ago [-]
There is no world in which giving cash or territory to the Chinese Communist Party would be acceptable to US taxpayers, regardless of the consequences.
mapt 69 days ago [-]
We've been doing it since Deng for the sake of making a few CEOs and shareholders richer. China operates or is monopsony sponsor of numerous pieces of infrastructure around the world in the name of trade.
tehjoker 69 days ago [-]
i think you mean war-hawk capitalists, this taxpayer thinks cooperation is fine
mionhe 69 days ago [-]
Not in that context.
China as a whole is seen differently than the Chinese Communist Party.
blackeyeblitzar 69 days ago [-]
Or just destroy their rockets and launch complexes. It’s better than Kessler syndrome.
immibis 69 days ago [-]
They, in turn, will destroy ours, and then you have basically caused the same outcome as Kessler syndrome: nobody can launch things to space.
blackeyeblitzar 69 days ago [-]
[flagged]
mapt 69 days ago [-]
It is trivial to retaliate in orbital disputes, and ASAT warfare produces long-lived hazard which cannot be cleaned up. Imagine two rival nuclear plants in nearby cities buying artillery and shelling each other, including with aerially deployed landmines.
Either you get along or you do not get to be a spacefaring civilization.
neilv 69 days ago [-]
Please don't commit acts of war. War is bad.
throwaway290 69 days ago [-]
"Please don't hurt the bully in the playground, fighting is bad"
The bully isn't going to learn with this implicit encouragement.
neilv 68 days ago [-]
Neither kid is an angel, but they both are smart enough not to risk an all-out fight with each other.
maxglute 69 days ago [-]
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 since it saves entrants from going extra 300km, but imo proximity also greatly enhances chance for friction... i.e. if everyone chilling around same plane, and it's going to get magnitude more croweded, expect a lot more overt/hidden space war assets there to trigger kessler.
m4rtink 69 days ago [-]
Others would use theblower orbits - but it is just not viable for them, as their rockets suck (eq. are not reusable) and thus they need to put their few expensive satellites with meager propulsion capabilities higher to last longer. Not to mention spot beams being wide enough with so few satellites.
maxglute 68 days ago [-]
>others would use theblower orbits
Orbital slots are managed by ITU United Nations International Telecommunication Union who manages availability / congestion. SpaceX reserved substantial % of sub 500 km slots. Hence PRC announching their megacontestallations to reserve 500km+ slots, specifically because there isn't enough room in sub 500km for another mega constellation so they're grabbing next best ones.
PRC megaconstellation is targetting 500km+, they're not going to put up 10,000s of mega constellation without economic reusable, hence many options under development. They're choosing orbits based on assumed reusables not current launch costs / vehicles, which btw LM5 is $3000/kg, or ballpark enough to F9/kg for disposable megaconstellation launches despite cost. But bottleneck is resusable vehicles can sustain the required tempo for megaconstellation that disposable can't.
perihelions 69 days ago [-]
No; rather, that commenter's argument was
"The most tempting orbits are the ones in upper LEO that permit them to launch fewer satellites."
We're talking about megaconstellations for communications, you want lower for latency, stronger signal (denser/less distance for beamforming) for better data through put -> less satellites for more coverage, and costs is cheaper since less energy. Realistically starlink has combination of 340km-1200km satellites working together, but the critical point is SpaceX reserved a lot of the sub 500km orbit slots with ITU (UN agency who manages orbits), so PRC competitors have no space real estate to try to throw up another mega constellation that can mimic spaceX economics due to location, location, location. Hence PRC registering Thousand Sails at 800km, Guowang at 500km-1200km orbits, etc, which according to OP is exponentially bad for Kessler (I have no idea). So either ITU opens much more 400km slots, or all the megaconstellations going forward going to satuate >500km LEO. Part of the reason PRC rushed to announce their megaconstellations before they even had reusable was to reserve the next closest available orbit slots that they can.
MrBuddyCasino 68 days ago [-]
There is no such thing as international law. There are only voluntary agreements.
maxglute 68 days ago [-]
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.
lupusreal 69 days ago [-]
> Stopping China's (highly strategic, military) satellite constellations isn't a "small amount of diplomacy". It's an impossibility.
Put 100k boost-phase interceptors into LEO. Permit them a fixed quota of launches per year, shoot down the rest. Pax Americana.
perihelions 69 days ago [-]
Then they'd retaliate in kind, and we'd get nowhere. It's certain they have that capability, or can develop it.
We stand to lose a lot more from a space war, right now, than anyone else. We (US/west) hold the lion's share of space commerce and orbital launch capacity. "Earth orbit is free and open for everyone" is more than Star Trek idealism—it's a precedent we've set that benefits us, especially.
lordgroff 68 days ago [-]
We've seen Russians shoot their own satellites, officially to ensure no large object re-entry (or some such nonsense, I don't remember), but I'm 10000% that it's a demonstration to the United States. If the Russians can do it, I'm sure China either already can or is very close to there. It's time to stop pretending that US can enforce rules by fiat without ramifications that scale from getting space assets blown up to a global war.
The world is already dangerously unstable and here we are discussing new ideas on how to make it more so.
poulpy123 69 days ago [-]
you mean total nuclear war
lupusreal 68 days ago [-]
Once a boost-phase interception constellation is demonstrated, nuclear war would be infeasible. They could try it with cruise missiles but that would only ensure their own destruction. They could try launching their own BMD constellation but that can be denied by the first.
tehjoker 69 days ago [-]
basically, it sounds like the U.S. should not treat China as a competitor and we should cooperate. this insane hypercompetition for literally no reason (other than US capitalists wanting to remain dominant) is going to destroy us all.
mapt 69 days ago [-]
I make no claim about what we should do in other contexts, only that mutual destruction of access to orbit is so easy to achieve we're currently careening towards it full speed without what politicians perceive as 'open hostilities'. This particular domain requires an approach more like OPEC than like the Cold War, and the consequence of failure to collaborate is you never get to play around in orbit again.
shiroiushi 69 days ago [-]
You think the Chinese capitalists aren't also trying to become dominant?
tehjoker 68 days ago [-]
They are, but China regularly dispossesses them and sometimes executes them, so the communist party, with huge popular membership, is in control.
shiroiushi 68 days ago [-]
I'm talking about the CCP itself, not the various business people running other companies there. The CCP are capitalists, in case you haven't noticed. (I know, Americans can't really wrap their heads around that one.)
autoexecbat 69 days ago [-]
> upper stages designed to explode into a thousand pieces at the target altitude
By this do you mean at the 800km altitude?
mapt 69 days ago [-]
Yes. In a lot of historical spaceflight programs, the stage used in the upper atmosphere stayed with you to the final orbit, and was detached at low speed there. This saved you from having to design your satellite with significant onboard propulsion. Some of the upper stages were able to vent remaining propellants or pressurants, some were allowed to heat up until the pressure vessel exploded.
Suffice it to say this is not sustainable for megaconstellations in thousand years orbits. The responsible thing to do with that kind of scale involves reliable, redundant, prompt de-orbit of upper stages, and ideally for high-thrust, high-mass, high-engineering-margin-of-error atmospheric upper stages never to make it that far into the mission.
68 days ago [-]
aaron695 69 days ago [-]
[dead]
leptons 69 days ago [-]
>I don't know how to sell the urgency of this predicament. You can have as many satellites as you want, a million uncoordinated bodies, at 400km because direct collision potential scales with (satellite count / orbital lifespan) ^2 . At 1000km, satellites decay so slowly we are already too crowded; we have already overused the space. We are speed-running the end of the space age and we are doing it to save a small number of dollars and to avoid a small amount of diplomacy.
This sounds like the most first-world-problem ever. It realistically affects practically nobody alive, nor would it ever. Most people will live and die on the planet's surface and never visit space, nor do they need to. There aren't too many space-based services that are really necessary to life on earth. Nobody really needs internet in the middle of nowhere. Sure, it's nice to have, but that's a first world problem that few people have.
chrisnight 69 days ago [-]
Having satellites orbiting the planet is more beneficial than just solving the first-world problem of “knowing where you are” or “having Internet”.
NASA has done a large amount of work to use satellite data to forecast and then work to improve agricultural yields covering the entire planet. It definitely isn’t necessary, but to dismiss the improvement that has been made is crazy, and I’d hardly call “feeding people around the world” a first-world luxury given by space travel.
hakfoo 69 days ago [-]
We can and should have satellites, but we can certainly be thrifty with how we use them.
The megaconstellation concept isn't necessary for most of the "cool stuff you can do with satellites." You might need a handful of weather or GPS satellites, and you can be more selective for orbits and lifecycle management if you're a responsible government operator.
The Starlink fiasco (and its clones) solely exists because we're abysmal at getting telecom projects built. If 80% of the country had the network connection you'd expect by 2024-- something like symmetric 10Gbps FTTH for $150 per month, and the other 20% was on a "real soon now" waiting list, there's precious little business case for Starlink.
Think about it: It was easier to plan out and deliver DOZENS OF ROCKET LAUNCHES AND A GALAXY OF SATELLITES than to tie down our existing telecom firms until they actually built a decent network, using technology like "backhoes" and "fibre-optic cables" that have existed for decades, cost next to nothing, and don't require literal rocket scientists to deploy.
The American telephone network under Ma Bell was almost a Wonder of the World for its scale, resilience, and universal accessibility-- and in barely one generation we ripped it out and failed to replace it with anything comparable.
I would argue the case there's a marginal case for one modest capacity public data constellation. The business case is basically Iridium warmed over-- for the places where there is no other practical option (ships at sea, completely undeveloped territories)-- you can pay $10 per gigabyte for 128k down, or to support some form of 911 outside of cell ranges. Arguably, we already had the infrastructure for that with the pre-Starlink satellite products (Viasat/Hughesnet)
But we hardly need every major power (and probably a bunch of private competitive duplication) blasting crap into space to make the deluxe version that's still not as good as a fibre running to your home.
nwiswell 69 days ago [-]
> It realistically affects practically nobody alive
Do people in the Global South not use GPS or consume weather forecasts?
leptons 69 days ago [-]
Sure, GPS is nice to have, but we lived without it for many centuries before it, it's also a "first-world-problem" if it goes down. GPS is also notoriously susceptible to ground-based jamming. And because of that there's also other ways to track position. Weather forecasts are nice to have, but often wrong. My original comment was framed more towards space travel.
minetest2048 69 days ago [-]
The thing is that GPS doesn't just do positioning. If we lost GPS then we can just
look at road signs (hopefully).
GPS also provides time synchronization to a lot of very important telecom infrastructure.
To prevent 4G base stations and digital TV transmitters from interfering with each
other, their transmit reference clock frequency need to be disciplined to within 50 ppb
and their time need to be synchronized to less then 1 us.
And technology leapfrog effect means that third world countries will be significantly affected
Exactly that. In many parts of Africa the middle of nowhere is full of people. In many places mobile phones are the only way to get internet. I can't wait for starlink to be available here. Getting internet is not a first world problem.
wiml 69 days ago [-]
> Weather forecasts are nice to have, but often wrong.
I think you are really, really underestimating the importance of weather forecasting to modern agriculture (and therefore global stability), shipping and transport, logistics, energy infrastructure, and on and on.
It adds to a pretty large body of literature around this subject, the gist of which is "risk is going up, but we don't really have a good way of estimating what that means in terms of actual collision rates".
69 days ago [-]
benchmarkist 69 days ago [-]
As long as it is militarily and commercially viable then the number of satellites will continue increasing, regardless of what academics have to say about collision rates. As per usual this is a coordination problem and in case people have not noticed nations are becoming less coordinated and more insular.
akira2501 69 days ago [-]
> in case people have not noticed nations are becoming less coordinated and more insular.
And what is your yardstick for measuring this? As far as I can tell this is the opposite of true. It's a popular national news meme but I don't believe it's been measured in any reliable way.
bragr 69 days ago [-]
I don't know about whether it is more or less common, but there has been international drama over conjunctions over the last several years
I won't comment on the broader point about how insular countries are becoming, but on this specific topic I'd say that the international reaction to global warming, which appears to be a very similar situation, shows exactly how little action is likely to happen.
benchmarkist 69 days ago [-]
[flagged]
akira2501 69 days ago [-]
> so you can greatly simplify your sentence
You didn't need to use "greatly" here because the suggestion you're offering without being asked is not particularly great or meaningful.
> I think that would greatly aid in your online communications.
I communicate online just fine, thank you, I'm also happy to be an individual and to allow that individuality to be expressed through my communications.
Thanks again for the unwelcome and unnecessary advice. Please don't use your time to police other peoples writing. It's rude.
benchmarkist 69 days ago [-]
I would recommend you take your own advice.
akira2501 69 days ago [-]
You are unwilling to adhere to your own standard? Interesting. What happened? Was it that someone else used this technique against you in the past to make you feel small? And now you've stored in some kind of quiver of ready to use insulting behavior to avoid any sort of confrontation or perceived failure? Then because of this you're made awkward and uncomfortable when it doesn't play out the same way as before?
benchmarkist 69 days ago [-]
In psychology that's called projection. I highly recommend looking into it.
Dylan16807 69 days ago [-]
"True" here is not a boolean, it's the truth of the matter.
The claim is that coordination is decreasing. Calling that "false" might mean coordination is steady. Calling it the "opposite of true" means that coordination is increasing.
benchmarkist 69 days ago [-]
That's a possible interpretation but the verbosity of the original statement hinders understanding the actual intent which is I why I recommended simplifying and removing unnecessary redundancies.
Dylan16807 69 days ago [-]
It's 40 words and makes three separate points in those words. I don't think it's too verbose, and I don't think your suggestion helps.
benchmarkist 69 days ago [-]
Everyone is entitled to their opinions.
Oarch 69 days ago [-]
There might be a cool storyline where we have to use enormous ground based lasers to clean up and start again.
Could even look a bit like the iconic Gibraltar WW2 search lights photographs.
jcgrillo 69 days ago [-]
What would zapping a satellite with a laser achieve? I suppose if you get it hot enough to melt everything, without anything flying off, then it would turn into a spherical drop of molten scrap... but then what?
aeternum 69 days ago [-]
You ablate part of it on the prograde side to create a small retrograde thrust which will deorbit it.
I think the right move is to merge this approach with goo blobs. We launch a large goo blobs or nets into a few strategic geostationary orbits and now you only have to ablate objects so they hit the goo then deorbit the goo once it is full (or just leave it there) as they would be large known orbits.
ZYbCRq22HbJ2y7 69 days ago [-]
I assume the poster means to change its trajectory.
sfink 69 days ago [-]
By adding energy (and momentum)? That seems unlikely to work. I guess you could try to shoot at things headed towards you over the horizon, to slow things down?
I was assuming it was to vaporize things to make the re-condensed remnants small and dispersed enough to be less of a problem. Though that seems like a tough problem if you have to stay trained on an orbiting bolt for any length of time, as the atmosphere wobbles your laser around.
titzer 69 days ago [-]
Well the targeting angle could be low to the horizon, aiming into oncoming debris, reducing its orbital velocity, so that it deorbits faster. The vertical component of the vector would be minimized. A low angle reduces laser efficiency due to more atmospheric interference, but oblique enough it would work. Nearly all man-made satellites (and space junk) orbit in the direction of Earth's rotation because of launch boost, which makes this easier.
0xbadc0de5 69 days ago [-]
My understanding was always that LEO is much less of a Kessler risk due to atmospheric friction - ie: in the absence of active control and regular correction, LEO objects will gradually de-orbit themselves. It's the the higher geostationary orbits that pose the problem.
aidenn0 69 days ago [-]
Depends on where in LEO. Explorer I had a perigree of about 350km and lasted for 12 years, though the orbit was highly elliptical. 900km and above is stable for thousands of years and well within the (circular orbit) LEO ceiling of 2000km.
The parallels to global warming appear to be close enough that this could be a good area to study what actually changes behavior on a global scale for a global environmental problem. I suspect this is easier to 'fix' mainly because there are fewer entities involved so not a total parallel, but it still might be informative to see when in the crisis arc action actually starts happening and what messaging impacted that timing.
exabrial 69 days ago [-]
VLEO/LEO is the safest place to put satellites is it not? They'll eventually deorbit themselves if you do nothing, no?
The worst place for space junk is high orbits it would seem like. Earth was wildly visited by an Apollo rocket stage a few years back! That is pretty wild.
69 days ago [-]
GoblinSlayer 68 days ago [-]
Maybe it's a feature. If you want to build a large spaceship on the orbit you have a problem how to launch all the needed material, but with a lot of garbage already up there, you can just recycle it on spot, everything is already launched.
donaldihunter 69 days ago [-]
I love Sabine Hossenfelder's videos but the audio effects on the transitions are killing me.
throwaway314155 69 days ago [-]
They're a little too similar to my phone's built in sounds I suppose. Nothing I can't get over though. What about them is "killing you"?
a2800276 69 days ago [-]
I wish she would put on a different shirt every once in a while.
lasers. autonomous fan-beam laser sats to vaporize prograde surfaces of debris to lower altitudes.
68 days ago [-]
m3kw9 69 days ago [-]
I would think newer sats will have collision avoidance capabilities and older ones will just crash. Maybe even clean up sats will be developed to collection them
michaelmrose 69 days ago [-]
Leo starts at 7.8 kilometers per second and speed plus secondary and subsequent collisions with very small debris makes it impractical. Also carrying fuel to react frequently would dramatically change the entire mission.
If your non refuelable sat is good for 6 months it probably no longer makes sense to launch it.
bagels 69 days ago [-]
Satellites fail (lost control, or spontaneously explode). Very small debris is everywhere and under 5-10 cm largely untracked, but some are working to fix this gap.
There is no incentive large enough for cleanup (it's expensive, nobody can/wants to pay, and there are a lot of objects)
bell-cot 69 days ago [-]
With currently deployed tech, most of the smaller orbital debris is not (usefully) track-able.
At orbital velocities, you gotta know it's coming to be able to avoid it.
And a orbital velocities, the untrack-able stuff can still kill a satellite.
resters 69 days ago [-]
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 malicious Kessler style attacks, etc.
bagels 69 days ago [-]
"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.
Those are interesting resources! I meant armored in more of a figurative sense, as in "prepared to defend itself against offensive collisions".
to11mtm 69 days ago [-]
That helps nothing on the civilian side. Blowing up a sat will do nothing but raise long term risk.
Some sort of platform that can launch 'space drones' to deorbit a dead satellite before it crashes or if something else would happened to cause a collision, that could be useful, but, probably expensive.
lxgr 69 days ago [-]
What do you assume happens to a "neutralized threat" in terms of space junk?
resters 69 days ago [-]
Perhaps it is recycled aboard the large armored satellite or propelled into the Earth's atmosphere so it can burn up.
And now the rest of the world is trying to catch up in a sort of arms race, and not taking any care about debris concerns. The most tempting orbits are the ones in upper LEO that permit them to launch fewer satellites.
SpaceX are going to end up well under 500km (orbital lifespan: a decade) before things are finished, and they switched to very low orbit staging with SEP spiral out to reach final orbit a ways back.
China's newest constellation Thousand Sails is at an altitude of 800km (orbital lifespan: thousands of years), with a thousand satellites in the works over the next year or so and 14,000 planned, and they're launching them using chemical upper stages designed to explode into a thousand pieces at the target altitude. This is sufficient for Kessler Syndrome all on its own, without counting interactions with anything else up there. A catastropic debris cascade at 800km percolates down to lower altitudes over time and impacts.
We need viable treaties limiting development beyond 400 or 500km and we need them ten years ago.
I don't know how to sell the urgency of this predicament. You can have as many satellites as you want, a million uncoordinated bodies, at 400km because direct collision potential scales with (satellite count / orbital lifespan) ^2 . At 1000km, satellites decay so slowly we are already too crowded; we have already overused the space. We are speed-running the end of the space age and we are doing it to save a small number of dollars and to avoid a small amount of diplomacy.
This is not something we get a do-over on. There is no practical way to collect ton-scale debris at present, no way to track kilogram-scale debris, no practical way to shield pressure vessels against gram-scale debris, and even milligram-scale debris can hit with the force of a bullet. After collisions start occurring at a rapid clip, the mass of potential impactors quickly forms a long tailed lognormal distribution that denies us space for centuries.
As in, is it the thing that makes it so no one else has broken out of their planet to come visit us?
I could totally see it being the case that as soon as a civilization gets good enough at putting stuff into space, they start putting a lot of stuff into space and then things start crashing into each other to the point that they can’t ever launch any more things into space and become stuck. Trapped by the artifacts of their own progress
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.
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?
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.
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 any threat to civilization, whereas nuclear winter is already very capable of wiping it out.
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 cloud as well causing issues, at least until the sun and moon gravity perturbs it enough.
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.
So unless somebody maliciously launches e.g. a bunch of ball bearings in the same orbital plane but opposite direction, the chances of "wrecking GEO" seem much lower (although the consequences would, as you say, probably be much more severe and long-term).
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-...
It's new information to me, though. Thank you.
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.
You look at which satellites poofed and then figure out the maximum extent their debris could have drifted.
Every collision generates hundreds, maybe thousands of pieces of debris, only the largest of which are trackable.
Imagine a bullet circling your head at mach 25. Now imagine a second bullet, circling your head at a slightly different angle, at a slightly different distance from your head. There's a chance that they could collide, and the resulting explosion would leave a great deal of dust... on a mixture of velocities, still circling your head. Now add a third bullet, also on a slightly different vector; Make sure that it doesn't collide with any of that dust!
The actual situation is we aren't dealing with 3 bullets or 100 bullets, we have ~170 million objects orbiting the Earth, and only around 50,000 are large enough to track. They are all moving fast enough in relation to each other that a collision would result in a sizable explosion, not an elastic agglomeration. We have no way of removing them.
The good news is that there is a large volume of space for them to exist in. The bad news is that as we continue to fill it up, odds of collisions increase, and every collision spawns many, many more objects.
I’m saying send reinforced rockets through the orbits that absorb the collision instead of generating more dust. That should let you clear a path through all orbits that intersect your path. It’s hard to do and the 3d aspect of it might make it expensive but conceptually it could be a solution. Or use super powerful lasers (potentially mounted on a satellite) to deorbit the dust
No such material exists, nor can it be made from any matter that is based on electrons bound around a nucleus — the force of impact will break any such material.
> It’s hard to do and the 3d aspect of it might make it expensive but conceptually it could be a solution.
"expensive but conceptually it could be a solution" is also why we don't have an Orbital Ring instead of rockets: https://en.wikipedia.org/wiki/Orbital_ring
The cost requirement for getting something to space with enough momentum to do the cleanup, even if it was able to survive the impacts, would be comparable to the entire cost of getting the stuff constituting the mess into orbit in the first place: bad enough to be prohibitive even today with relatively little mess, much worse if there's an actual Kessler cascade.
> Or use super powerful lasers (potentially mounted on a satellite) to deorbit the dust
Could work for the bigger bits, but don't put the lasers on a satellite: 1) Power is short up there, as is cooling, much easier to put a bit laser on the ground and waste some energy going up through the atmosphere; 2) if you solve that constraint, you've now got an orbital laser that's an obvious and easy-to-hit target for all foreign powers to get upset about even if you didn't want to weaponise it.
For the smaller stuff, you can't see the dust to target it in the first place.
"Clearing a path" is something you can do with a bulldozer through a traffic jam, but imagine clearing a path through a belt road by driving through the flow of moving traffic sideways at speed. Ultimately you can't hit every car in the outer lane with just one bulldozer, and the cars will close in and fill gaps because they're moving at slightly different speeds.
The easy elastic collisions you're imagining also just can't occur at these relative velocities. When something hits it looks more like an explosion than a "catch". If you shoot a local stone monument with high explosive artillery shells what happens? Does it reduce the number of things flying through the air or increase it?
"Just" how? Orbital collisions happen at an average of 10km/s, you're going to make what, some kind of sponge that can get hit by a chunk of satellite going ~8x faster than a bullet and absorb it and slow it to a halt without fragmenting at all? Good luck.
> Do that a few times and then all other rockets just reuse the path that was cut?
Things in orbit are constantly moving, you can't "clear a path" any more than you can, IDK, make a safe route through a forest by walking through it once and moving any bears you encounter a couple of feet.
The "clearing a path" idea is inane, but we do know how to absorb hypervelocity debris impacts while generating a net negative amount of debris.
https://www.researchgate.net/figure/Whipple-shield-concept_f...
We need to start by understanding it. I'm having trouble finding this paper right now. But to date, all calculations have shown that Kessler syndrome as a generalised phenomenon is incredibly hard to trigger. Even intentionally. Especially in LEO. (Intentionally triggering it is of interest for strategic ASAT denial.)
> the mass of potential impactors quickly forms a long tailed lognormal distribution that denies us space for centuries
No, it denies certain orbits. (Again, barring some new orbital dynamic haven been discovered by this paper.)
Circularisation isn’t the unexpected part. Sphericalisation is. One requires orbits to desync. The other requires plane changes.
Roughly 3 minutes in: https://www.youtube.com/watch?v=9cd0-4qOvb0
https://en.wikipedia.org/wiki/Nodal_precession
It doesn't even need to be factored in, though, if different planes are colliding with each other and energetically generating a spectrum of new orbital vectors (many less than circular) from impact. This effect colludes with altitude drop from orbital decay and the tendency to circularize orbits by perigee drag, to make it so that higher orbit debris percolate into lower orbits over time.
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 they need to do regardless.
And even then the negotiation process will take decades so that means no LEO satellites available for anyone for several decades.
The real issue is regulatory, not technical. See https://news.ycombinator.com/item?id=42199498
How does this make sense? Other countries could clearly decide however they like, because they don’t need to come to the negotiating table.
However your idea of "annulling" permits already given out isn't necessary, or politically feasible, or even desirable.
"Annulling" is just one HN user's jealous destruction fantasy.
I was the one who implied the status quo, i.e. countries putting things into orbit way above 500km and nobody stopping them, is likely to prevail… with even the next best alternative very unlikely to happen.
Because this thing is happening right now, it's happening fast, and it's happening without any effort to fight against the trend.
If your answer is "let's revisit this in 2050", then it isn't an answer.
What is January 6th if not a concrete example of recent political instability?
As for foreign policy consistency, 7 administrations takes us back to Reagan... The entire movement to sell out our industrial capacity to China and now the movement to try to reverse that have occurred in this time frame. This is just as important as our endless wars in the middle east, imo.
I don't disagree totally but I felt the need to put some nuance here.
If so then what countries in Europe (sans the Balkans) or East Asia do you think are less politically stable than the US?
You're saying "nothing bad will happen because nothing bad has happened so far". There's a first time for everything.
[1]
> What emerged out of this economic crisis was a reform movement led by Mohammad Khatami, who won a presidential election in 1997 on promises to cultivate civil society, fix the economy, and replace a "clash of civilizations" with a "dialogue of civilizations." The cultural transformation unfolded over the next several years was remarkable. The share of university graduates who were women topped 60 percent, a new generation of intellectuals began to favorably cite Western philosophers, and religion more or less stopped policing the daily lives of most Iranians. By 2000, the Economist was reporting that according to Iran's own clergy, fewer than 2 percent of Iranians attended mosque on Fridays. On the economic side, the neo-liberalization of Iran intensified; small-scale factories were exempted from labor laws, and state-owned industries were privatized (loosening the state's grip on the economy was thought to be the best way of decreasing state interference in Iranians' private lives). Iran's relationship with foreign nations, even the US, also improved considerably. President Clinton eased up on the economic sanctions that Reagan had put in place in 1987, and Khatami appeared on CNN to talk about his admiration for the American nation and people. Al Qaeda's attack on the United States on September 11, 2001, was met with a massive outpouring of sympathy for America in Tehran, with enormous crowds holding candlelit vigils and some sixty thousand people observing a moment of silence at a soccer match on September 23.
[1] https://www.nplusonemag.com/issue-37/politics/we-used-to-run...
President Bush certainly bungled the situation as well.
Both of which demonstrate that our species is much better at understanding how to scale madness and destruction than how to scale sustainable activity.
Stopping China's (highly strategic, military) satellite constellations isn't a "small amount of diplomacy". It's an impossibility.
(It's even their declared planning that deliberate Kessler cascades are on the table [0]—to try to ground this discussion in diplomatic reality).
[0] https://www.scmp.com/news/china/science/article/3178939/chin... ("China military must be able to destroy Elon Musk’s Starlink satellites if they threaten national security: scientists")
There is no stable Mutually Assured Destruction Nash equilibrium here, if either of us does this thing it causes dramatic harm to both.
Not regarding that as a worthwhile goal is "mineshaft gap" thinking - a zero-sum mentality entirely ignoring our collective advantage in order to pursue competitive advantage.
It is perfectly feasible to run a Chinese constellation alongside Starlink sharing the same space, orbitally. Very low orbits are self cleaning.
- "Launch their satellites for them, at 400km."
No reasonable person would help their adversary build powerful weapons that could immediately be used against them. The point of satellite constellations—Chinese or American, either—is to create undeniable, high-bandwidth communications for armies; to create real-time (as opposed to sporadic) satellite imagery for armies; to create, in short, an overwhelming situational awareness advantage in a conventional war.
- "Give them cash or territory."
We are not giving away countries.
China as a whole is seen differently than the Chinese Communist Party.
Either you get along or you do not get to be a spacefaring civilization.
The bully isn't going to learn with this implicit encouragement.
Orbital slots are managed by ITU United Nations International Telecommunication Union who manages availability / congestion. SpaceX reserved substantial % of sub 500 km slots. Hence PRC announching their megacontestallations to reserve 500km+ slots, specifically because there isn't enough room in sub 500km for another mega constellation so they're grabbing next best ones.
PRC megaconstellation is targetting 500km+, they're not going to put up 10,000s of mega constellation without economic reusable, hence many options under development. They're choosing orbits based on assumed reusables not current launch costs / vehicles, which btw LM5 is $3000/kg, or ballpark enough to F9/kg for disposable megaconstellation launches despite cost. But bottleneck is resusable vehicles can sustain the required tempo for megaconstellation that disposable can't.
"The most tempting orbits are the ones in upper LEO that permit them to launch fewer satellites."
Higher altitude => wider coverage => fewer satellites
Put 100k boost-phase interceptors into LEO. Permit them a fixed quota of launches per year, shoot down the rest. Pax Americana.
We stand to lose a lot more from a space war, right now, than anyone else. We (US/west) hold the lion's share of space commerce and orbital launch capacity. "Earth orbit is free and open for everyone" is more than Star Trek idealism—it's a precedent we've set that benefits us, especially.
The world is already dangerously unstable and here we are discussing new ideas on how to make it more so.
By this do you mean at the 800km altitude?
Suffice it to say this is not sustainable for megaconstellations in thousand years orbits. The responsible thing to do with that kind of scale involves reliable, redundant, prompt de-orbit of upper stages, and ideally for high-thrust, high-mass, high-engineering-margin-of-error atmospheric upper stages never to make it that far into the mission.
This sounds like the most first-world-problem ever. It realistically affects practically nobody alive, nor would it ever. Most people will live and die on the planet's surface and never visit space, nor do they need to. There aren't too many space-based services that are really necessary to life on earth. Nobody really needs internet in the middle of nowhere. Sure, it's nice to have, but that's a first world problem that few people have.
NASA has done a large amount of work to use satellite data to forecast and then work to improve agricultural yields covering the entire planet. It definitely isn’t necessary, but to dismiss the improvement that has been made is crazy, and I’d hardly call “feeding people around the world” a first-world luxury given by space travel.
The megaconstellation concept isn't necessary for most of the "cool stuff you can do with satellites." You might need a handful of weather or GPS satellites, and you can be more selective for orbits and lifecycle management if you're a responsible government operator.
The Starlink fiasco (and its clones) solely exists because we're abysmal at getting telecom projects built. If 80% of the country had the network connection you'd expect by 2024-- something like symmetric 10Gbps FTTH for $150 per month, and the other 20% was on a "real soon now" waiting list, there's precious little business case for Starlink.
Think about it: It was easier to plan out and deliver DOZENS OF ROCKET LAUNCHES AND A GALAXY OF SATELLITES than to tie down our existing telecom firms until they actually built a decent network, using technology like "backhoes" and "fibre-optic cables" that have existed for decades, cost next to nothing, and don't require literal rocket scientists to deploy.
The American telephone network under Ma Bell was almost a Wonder of the World for its scale, resilience, and universal accessibility-- and in barely one generation we ripped it out and failed to replace it with anything comparable.
I would argue the case there's a marginal case for one modest capacity public data constellation. The business case is basically Iridium warmed over-- for the places where there is no other practical option (ships at sea, completely undeveloped territories)-- you can pay $10 per gigabyte for 128k down, or to support some form of 911 outside of cell ranges. Arguably, we already had the infrastructure for that with the pre-Starlink satellite products (Viasat/Hughesnet)
But we hardly need every major power (and probably a bunch of private competitive duplication) blasting crap into space to make the deluxe version that's still not as good as a fibre running to your home.
Do people in the Global South not use GPS or consume weather forecasts?
No GPS means no 4G and no digital TV. And technology leapfrog effect means that third world countries will be significantly affected, as they jumped directly to mobile phone: https://www.cio.com/article/194000/what-does-technology-leap... . And countries are moving toward digital TV from analog TV: https://en.wikipedia.org/wiki/Digital_television_transition because they want to free up the spectrum for cellular network.
This is bad. The transmitter towers aren't moving anywhere soon, so the obvious solution is to move them to fiber timing network. Wired is always more reliable then wireless anyway, ask Linus Tech Tips. Only China understands this though: https://www.gpsworld.com/china-finishing-high-precision-grou... and https://cpl.iphy.ac.cn/article/10.1088/0256-307X/41/6/064202 . EU is moving toward that: https://www.gpsworld.com/europe-moving-toward-a-timing-backb... . US is hopeless
Exactly that. In many parts of Africa the middle of nowhere is full of people. In many places mobile phones are the only way to get internet. I can't wait for starlink to be available here. Getting internet is not a first world problem.
I think you are really, really underestimating the importance of weather forecasting to modern agriculture (and therefore global stability), shipping and transport, logistics, energy infrastructure, and on and on.
It adds to a pretty large body of literature around this subject, the gist of which is "risk is going up, but we don't really have a good way of estimating what that means in terms of actual collision rates".
And what is your yardstick for measuring this? As far as I can tell this is the opposite of true. It's a popular national news meme but I don't believe it's been measured in any reliable way.
https://spacewatch.global/2021/12/spacewatchgl-share-chinese...
You didn't need to use "greatly" here because the suggestion you're offering without being asked is not particularly great or meaningful.
> I think that would greatly aid in your online communications.
I communicate online just fine, thank you, I'm also happy to be an individual and to allow that individuality to be expressed through my communications.
Thanks again for the unwelcome and unnecessary advice. Please don't use your time to police other peoples writing. It's rude.
The claim is that coordination is decreasing. Calling that "false" might mean coordination is steady. Calling it the "opposite of true" means that coordination is increasing.
Could even look a bit like the iconic Gibraltar WW2 search lights photographs.
I think the right move is to merge this approach with goo blobs. We launch a large goo blobs or nets into a few strategic geostationary orbits and now you only have to ablate objects so they hit the goo then deorbit the goo once it is full (or just leave it there) as they would be large known orbits.
I was assuming it was to vaporize things to make the re-condensed remnants small and dispersed enough to be less of a problem. Though that seems like a tough problem if you have to stay trained on an orbiting bolt for any length of time, as the atmosphere wobbles your laser around.
Anyone have an open link?
The worst place for space junk is high orbits it would seem like. Earth was wildly visited by an Apollo rocket stage a few years back! That is pretty wild.
If your non refuelable sat is good for 6 months it probably no longer makes sense to launch it.
There is no incentive large enough for cleanup (it's expensive, nobody can/wants to pay, and there are a lot of objects)
At orbital velocities, you gotta know it's coming to be able to avoid it.
And a orbital velocities, the untrack-able stuff can still kill a satellite.
In other words, welcome various "death stars" to keep order against malicious Kessler style attacks, etc.
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/im...
Some sort of platform that can launch 'space drones' to deorbit a dead satellite before it crashes or if something else would happened to cause a collision, that could be useful, but, probably expensive.