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

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.

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.

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.

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.

Do people in the Global South not use GPS or consume weather forecasts?

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

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")

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

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.)

You look at which satellites poofed and then figure out the maximum extent their debris could have drifted.

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.

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.

Every collision generates hundreds, maybe thousands of pieces of debris, only the largest of which are trackable.

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.

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.

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

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

Circularisation isn’t the unexpected part. Sphericalisation is. One requires orbits to desync. The other requires plane changes.

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.

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.

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.

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.

"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.

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.

"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?

Either you get along or you do not get to be a spacefaring civilization.

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're saying "nothing bad will happen because nothing bad has happened so far". There's a first time for everything.

China as a whole is seen differently than the Chinese Communist Party.

"The most tempting orbits are the ones in upper LEO that permit them to launch fewer satellites."

Higher altitude => wider coverage => fewer satellites

Both of which demonstrate that our species is much better at understanding how to scale madness and destruction than how to scale sustainable activity.

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.