Comment by mapt
20 hours ago
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.
> 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.
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.
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
Is Kessler syndrome the Great Filter (https://en.wikipedia.org/wiki/Great_Filter)?
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
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.
How can you get past that orbit if there is all this junk destroying your rockets????
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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.
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.
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> 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.
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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.
"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.
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Every launch failure will result in more debris and even lower probability of a successful future launch.
> 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.)
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.
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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).
[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")
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.
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.
Or just destroy their rockets and launch complexes. It’s better than Kessler syndrome.
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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.
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> Launch their satellites for them, at 400km. Give them cash or territory. Give away the farm. How doesn't matter.
That sounds not just expensive but unrealistic. I think it’s easier and more politically acceptable to just cripple their launch capabilities with cyberattacks or direct force. It’s not like the world trusts or likes the CCP, or looks favorably upon their aggression against Hong Kong, Taiwan, Tibet, Bhutan, Japan, the Philippines, Vietnam, etc. And this stakes are too high with orbital pollution
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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.
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.
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No; rather, that commenter's argument was
"The most tempting orbits are the ones in upper LEO that permit them to launch fewer satellites."
Higher altitude => wider coverage => fewer satellites
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There is no such thing as international law. There are only voluntary agreements.
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> 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.
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.
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you mean total nuclear war
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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.
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.
You think the Chinese capitalists aren't also trying to become dominant?
> upper stages designed to explode into a thousand pieces at the target altitude
By this do you mean at the 800km altitude?
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.
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.
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.
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.
Yeah well it means a lot of satellites are going to end up in space then.
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.
Going from a treaty and cooperation with Iran to cutting them off was a pretty substantial change that has already had global implications.
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.
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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.
> 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.
Humanity is a failed species. The engineers were right to send the xenomorphs.
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>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.
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.
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.
> It realistically affects practically nobody alive
Do people in the Global South not use GPS or consume weather forecasts?
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.
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