Abstract from the paper in the article:
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024GL109280
Large constellations of small satellites will significantly increase the number of objects orbiting the Earth. Satellites burn up at the end of service life during reentry, generating aluminum oxides as the main byproduct. These are known catalysts for chlorine activation that depletes ozone in the stratosphere. We present the first atomic-scale molecular dynamics simulation study to resolve the oxidation process of the satellite’s aluminum structure during mesospheric reentry, and investigate the ozone depletion potential from aluminum oxides. We find that the demise of a typical 250-kg satellite can generate around 30 kg of aluminum oxide nanoparticles, which may endure for decades in the atmosphere. Aluminum oxide compounds generated by the entire population of satellites reentering the atmosphere in 2022 are estimated at around 17 metric tons. Reentry scenarios involving mega-constellations point to over 360 metric tons of aluminum oxide compounds per year, which can lead to significant ozone depletion.
PS: wooden satellites can help mitigate this https://www.nature.com/articles/d41586-024-01456-z
SpaceX has been receptive to design changes to starlink in the past to minimize impact, like decreasing reflectivity and reflection angles for astronomers. They might be receptive to moving to different alloy for the body construction.
Magnesium comes to mind that would be light but expensive. Steel alloys might be cheap and heavy options for later when starship is operational. Would those have similar effects on ozone, or is it only the aluminum oxides?
Magnesium oxides can also serve as a catalyst for lots of reactions, but I’m not sure if it will have the same effect in this specific context, I’d guess it would.
That’s why I added the link to the wooden satallites, that also reduces the metal debris somewhat and reduces other effects like radio interference.
Wood is interesting, but the article doesn’t address off gassing at all, which is a huge problem for communication satellites. Is there a way to keep the wood from off gassing? For 3d prints in vacuum, they metal coat them to keep the gas inside. Or maybe you could resin soak them? With hopefully an extremely UV stable resin. But I didn’t know what the weight trade looks like then, resin is heavy.
But if you’re looking composites anyway, carbon fiber would be another great option. Lightweight but with a few manufacturing constraints. But should burn up to carbon dioxide on reentry.
I just read an interesting research article from NASA that shows that carbon fiber survives reentry better than our previous scientific consensus claimed.
Some carbon fiber will burn up into carbon dioxide, but a good chunk of it will surprisingly survive reentry conditions. I think you are very right that it should be a better material to use for starlink.
I feel like it shouldn’t even have to be said out loud that gravity and weight correlate, but their orbit would be heavily impacted by replacing aluminium with five times as much steel for the same durability. You might be able to get away with slightly less if you consider the steel has more heat resistance, but idk.
Yeah you’d need to put up fewer sats per launch. But they might still have enough lift capacity on starship to do that.
Weight does not affect orbit. It affects the amount of fuel needed to reach orbit, and therefore cost, but not the orbit itself.
Exactly, it needs a higher angular momentum at the same altitude.
Another thing Elon is screwing up on
It’s like he became the opposite of King Midas.
I don’t know, maybe it is like Midas. The things he touches turn into something coveted, and therefore valuable, but also of little to no practical use, just like gold.
So… Let me get this straight… The satellites burning up are essentially creating aluminum chemtrails that my mother-in-law keeps going on about?
Aluminum is neurotoxic so yes
Quite possible. Let’s fix our ISPs so that all of humanity has access to bandwidth priced to a value that they can afford for their area. A huge project that means lots of union jobs and an economic payoff for decades. If we pull this off Starlink won’t have any customers except very marginal cases.
Fix the problem directly instead of fixing the solution unintended side effects
Gee, where are the boatload of billions that the US congress passed for nationwide broadband?
Fucking ripoff telecon companies.
They should just pay people to lay the cable directly instead of awarding it programmatically to companies.
That’s what my city is basically doing. They’re contracting with a local installer to lay cable, then selling service on that network. No money is being awarded, in fact the contract states that they get paid with part of the subscription fee, so they are motivated to get people connected quickly so they can start collecting. The city owns the network and ISPs compete over customers on that network. They claim it’ll take 2 years for everyone to be connected, which is pretty quick (but the proof is in the pudding).
Seems like a decent system to me. We’re being promised 10gbps available, but pricing details aren’t finalized yet (and my router only handles 1gbps anyway, and I’m too lazy and cheap to upgrade everything).
AFAIK, this plan was in the works before the infrastructure bill was passed, so I don’t think we’re taking money from that, but I could be wrong.
I got fiber in the middle of nowhere from it. ¯\_(ツ)_/¯
Whereas we are smack dab in the middle of cities, but just far enough out of reach to be stuck with 20Mb DSL that will never improve.
I’m a 7 minute drive from downtown and my options are satellite, cellular, or fixed wireless. Everyone around me has gigabit ethernet, but due to costs involved in running fiber and the fact my little community is mostly old folks (and thus likely not going to buy in) ISPs don’t want to “invest” in us.
I don’t know how much has changed, I did an internship with a major ISP while I was a student, at the time I was told that the stronger the local government the less fiber there was. And it came because of the tax code.
apparently fiber.ee is yt hd verified, never heard of it before, im using telia at the moment.
I thought that program was ended in 2018?
Why not both? I kinda want Starlink for road trips and camping. As in, pull into a national park, set up camp, do normal Internet things, then go hike the park the next day or whatever. I could even work from a national park if I really wanted to, which would be really cool.
You would think space engineers would‘ve run those numbers before sending tens of thousands of them in orbit. It‘s really annoying that we can only hope for the best at this point.
I fully expect they did. I think this is partly why Elon went from “there’s no planet B” to a Saudi simp. Way to much money to be made to waste time on the concerns of scientists and the welfare of the planet.
Why would you think that?
When I fire up the grill, I don’t do calculations on how much weight in CO2 I’m putting into the air and then extrapolate that to find the total mass of CO2 that grills generate globally. I usually just make burgers.
That space engineer made sure that they were on the right side of the rocket equation and they made it to orbit (which is hard on its own).
I agree that thorough environmental studies really ought to be happening, but I’m not surprised that aspects got missed.
I was just worried about Kessler syndrome and just felt relaxed that their orbits were low enough to naturally decay and never become a permanent problem. What this research seems to show is that the aluminum oxide dust does not settle in days/weeks, but it is fine enough to stay there for decades :/
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They do, and did. Perhaps this reaction with the ozone layer just hasn’t been considered until now.
it’s not just musk, Bezos too.
About 48 tons of meteorites enter the atmosphere every day. I couldn’t find the elemental distribution, but I’d guess there is some aluminum in there. How much of an increase is 14 tons aluminum per year over the many tons of aluminum entering the atmosphere already? That might be good to get a rough estimate of how impactful this is.
Even assuming the meteorites are 100% aluminum it’s a 30% increase which is quite significant.
From a short google search apparently only ~8% of asteroids in our solar system are metal rich which is mostly iron nickel. Rarer metals can be as rare as 100 grams per ton.
Which means of the 48 tons only 4.8 kilos could be aluminum. Compared to that the 14 tons would be a whopping ~3000% increase.
The asteroid weights are given per day while the sats per year.
Still only 1752 kg per year
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4.8 kg not 48kg
Isn’t it 48 tons of meteorites per day vs 14 tones of satellites per year?
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Al is a major element in the solar system. Most rocks have Al2O3 on the order of 3-10 wt.%. That includes chondrites (the major class of meteorite) which have plenty of feldspar, a mineral that’s like 20 wt.% Al2O3, and calcium-aluminium inclusions (CAIs), which are as their name suggests, Al-rich.
4.8kg per day gives 1.75 tons per year, giving an 800% increase. That’s still really big, thanks for tracking down the numbers.
I would put money down the meteorites are below 30% aluminum so I can’t see it being less than doubling.
48 tons per day, so it’d need to be less than 0.08% aluminum to double it.
ah. missed the per day vs per year thing.
damn, starlink is my only way to access the internet. I wish there were an alternative that’s usable. Traditional access providers don’t work and cell data is extremely slow and there’s no coverage where I live. I pay for Starlink with a bitter taste
Might I enquire as to where this remote location might be?
Like on a general basis, no need for addresses.
As a Finn I’m forever spoiled in terms of wireless coverage. We got tons of solitary forests. But you can get an internet connection in literally all of them.
97% of the country gets 4g. And not of the people. The country.
I live in rural California. We only just this year are able to pick up a faint LTE signal. I think it might get us a very unstable 1-2 Mbps if we hold the phone just right. We have no cable, DSL or other land-based options and because of the topography can’t pick up the local wireless provider, which is very expensive anyway - like $175/month for 50/5
So without Starlink our only options are crappy regular satellite providers like Hughesnet which impose very low quotas - 10 GB monthly for day time usage - and have insane latency.
It bugs the shit out of me I have to give money to that fuckwit but without it we live in the dark ages.
We’re in Mayotte. Two undersea cables connect us to nearby continents (cf submarinecablemap.com) but they’re down most of the time. We haven’t had a connection in the last six months so we finally subbed to Starlink. Well, strictly speaking there was a connection but it would take anywhere between 5mn to 15mn to load the text of a static webpage, no images or anything else… forget about sending data, using forums… I had to get out and walk uphill for a minute or two to use my phone’s cell data
My family has Starlink, they live in mountainous rural. Cell towers aren’t too far away, but mountains get in the way of decent signal. No one is running any cables their way, despite a local telco taking money explicitly for providing internet service.
We Finns don’t have any of those pesky mountains.
Rural US most likely. Place is too big, too few people to be worth for comoanies to invest. So many places only have 1-2 providers at best, afaik.
I love it when ppl from small countries don’t get why there isn’t wifi / cell coverage literally everywhere…
I think they’re aware, given they said they’re spoiled?
Finland is not a small country compared to its population density and distribution.
Finland has 18 inhabitants per km².
USA have 35 inhabitants per km².
Huh. TIL.
But these are sort of not that good indicators, because the US has huge population centers on the coasts, and nothing in the vast center.
That’s not a good measurement as populations are not spread evenly. You could have 10 000 people per km^2 in the US then have 0.001 people per km^2 in another
The Finn already addressed this in their first post: 97% of the country has 4g. That is country, not people in the country. So yes, a reindeer in Lapland has a better potential internet connection than many rural north americans.
Edit: I found some recent numbers: this carrier claims to provide 4g to 99% of the population, 5g to 96%. https://www.dna.fi/wholesale/about-us/networks That 2nd statistic must be pretty damn rare, the country of Nokia indeed.
My point was more that there is a lot more nothing land in the US
And why are you unwilling to accept that there is a lot of nothing land in Finland? Most of Finland is a lot of nothing land, plagued by mosquitoes in the summer and darkness in the winter.
Your country is neither unique, nor exceptional in this regard.
Yeah since most people don’t live in the parts of the country no-one lives in, when looking at how many people are covered, it gets pretty good. And we didn’t take long to get 5g to a lot of people.
Here’s a coverage map from Elisa. https://elisa.fi/kuuluvuus/
Tbh, that 4g coverage up north looks pretty damn good for how few people live there. To me it just makes no economic sense to provide that good a service there. So I’m curious and as a Finn you might know: does it make economic sense or was this investment done for other reasons?
You are absolutely correct that distribution matters. However, Finland has an even more uneven population distribution than the US. 75% of the population lives in the costal cities, with 30% of the entire population living in the capital region( density of 193 persons/km²). The entire rest of the country is not empty dessert ( which would require no services), but very sparsely populated rural woodlands, down to 2 people per km².
Density still is an overall useful quantifier given that extra knowledge, as providing services for a small population of only 5.6mio inhabitants is not easy either. Sure, providing coverage for the 75% in the cities is fairly easy. But that still leaves 1.5mio rural residents, which require huge investments in cable to supply with broadband. And due to the vast distances, you definitely cannot cover them with wireless alone, if you were thinking that.
Compare the diameter of the two countries
If you only look at one line between LA and NYC, that is a lot more cable being laid. Now add something remote like the middle of Alaska vs the middle of Finland. We can assume for this example that they both service 100 people but the cost to do so for the US is a lot higher
That’s why using density makes no sense
Laying even 10 times the cable should not be more difficult when you have 60 times the total population (335mio in US vs 5.6mio in Finland) and hence more resources.
And sure, Alaska definitely it’s expensive and inefficient to service, having a pop density of about 0.5 inhabitants per km². But unlike Northern Finland, most of Northern Alaska is in fact entirely void of human life and more akin to a desert. There really mostly are a handful of oil industry clusters and native communities. And still, the extremely low pop density means it’s only 730 000 people living in Alaska. That is 0.2% of the entire population of the USA. If you were to completely ignore and not service Alaska, you should have a an even easier time providing service to the vast majority of the US population in all the main states. I think it’s pretty clear this is a political failure and not a matter of financial resources or natural obstacles.
estona has cell coverage on it’s intire rail network with 5g wifi? i read the Wikipedia page for Elron
What about the remaining 3%?
Also, to (hopefully) answer your question:
Ignore Finland/Europe for a second and look at North America. The US has many population centers along the coasts and very few in the west inland. People still live there, so they need internet access, but oftentimes there aren’t enough people to justify expanding coverage across such a huge area without subsidizing said coverage with government funds or other customers, so there are bound to be coverage gaps if you don’t have unlimited money to throw at the problem. If you take a look at Canada, you can see how much worse the problem is as they have even more area to cover, and it reflects in the fact that they have some of the highest wireless prices in the world.
Also remember that these are wealthy countries. Plenty of other regions have the same problems with population density and physical size, and they can’t throw money at the problem like we can.
The TL;DR is that these deadzones exist in a ton of places because a lot of low-population areas are physically huge.
I remind you that it’s the remaining 3% of the country, physically. It’s not 3% of the population. It’s just some places in Lapland which don’t have the greatest coverage. And the 97% figure is 4g, 3g has better coverage.
The Northern part of Finland is very sparsely populated and people like internet and cables are very labour-intensive compared to setting up mobile network towers.
But yeah, compared to the US, we’re not really that sizable. We’re like the size of Montana or so, and they’ve around a fifth of our population.
tldr Yeah, it is about the size, but also, with Nokia and so on, we’ve sort of quite a lot of good know-how on building wireless networks. We’re the most sparsely populated country in the EU, but I think there’s quite a lot of Spain where there’s much worse coverage.
At least one hour outside any Midwest city.
We are in the mountains in rural Alberta
Majority of Canada is like that
lol that’s fantastic. Out in the forest with internet. How come, cell towers are closely packed ?
~75% of the country is forest, so it’s kinda hard to not be in a forest.
Idk if they’re closely packed.
Coverage map.
So they take 17 tons of emissions (from all satellites, not just starlink), which are basically nothing on an atmospheric scale, then extrapolate that to 360 and start freaking out. Peak quality journalism.
its not a jurnalist coming up with this its from a paper. And as far as i understand they took information on satelite mass increasefrom another paper which had a “a comprehensive body of data”(https://ui.adsabs.harvard.edu/abs/2020AGUFMGC0420004H)
burned wood in the upper atmosphere also catalyzes ozone depletion That’s why it was bad putting CFCs up there in the first place, almost everything catalyzes these reactions
Oh, so no Chlorine ever truly gets locked away from the ozone cycle…smoke particles will just keep reactivating it 😞
I thought that the idea was to stop crashing old satellites into earth and instead require they maintain enough propellent to move themselves off into a graveyard orbit.
That works for satellites in a Geostationary orbit, but Starlink satellites are in a Low Earth Orbit (LEO). While LEO is in space there are a tiny amount of atmospheric particles there which creates a tiny amount of drag. Things in LEO will come back down eventually.
Thanks Elon
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Idk, i think SpaceX is catching a lot of heat just because they have musk “at the helm”. He doesnt even do anything there, he isnt an aerospace engineer. They just let him sit in mission control so he can feel special. The actual work spacex is doing is revolutionary. Reuseable rockets are a seriously groundbreaking development. Almost everything you do these days relies on a sattelite connection, so doing that cheaper, more reliably, and less wastefully is massive.
Starlink is a different matter tho, its just another ISP but with a fancy connection method.
Almost everything you do these days relies on a sattelite connection
Except GPS and satellite TV, say what now?
My internet doesn’t rely on satellite, neither does basically anything else
Can you imagine the world without GPS at this point?
In any case since you asked the biggest things besides those are weather predictions, spying, part of the large region emergency response systems, research, and land management.
Fair enough.
I think starlink is more than that as even more things rely on a (good) Internet connection ingeneral than rely on satellites, and traditional connectivity methods leave many people underserved even in countries like America let alone the world.
It definitely has its problems, if nothing else that it’s privately owned and anyone who wanted to compete would then massively amplify those problems.
SpaceX and the reusable Falcon 9 is incredibly incredible. It has already eliminated lots of waste in the field of space travel.
If the Russians had not been rude to Musk, and hurt his little ego, SpaceX wouldn’t exist.
I guess we blame the Russians for this too then.
Be nice if you could go into a bit more detail about your thoughts on this. Rather than just asserting your conclusions.
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Ok congrats on successfully moving the problem backwards. You have made another assertion without evidence to backup your previous assertion without evidence.
I understand your opinion but it is just an opinion
Why?
I hate Elon, but he ain’t the only one trashing the LEO
Okay, but he’s trashing it the fastest and for the dumbest reasons.
If I have to compare, giving people in underserved areas access to the Internet is a better reason than spy sats or satellite TV.
Tv is still kinda important, like backup of streaming Tv (freely&freesat)
At least the article came with the numbers. Given what I regularly read about all the pollutants we daily pump into the atmosphere, the numbers in this article for the materials being atomized is…well, they’re very small in scale.
Basically, if a few hundred tons per year is hurting the ozone (and other things), just imagine what the billions of tons per year of emissions does.
The point here is not that aluminum oxide “pollutes” on its own, it is that it “speeds up” the harmful reaction between ozone and any chlorine (like CFC) “pollutants” up there without being consumed, so it keeps acting over 30 years. It makes all the pollutants you mention “more effective” at depleting ozone.
I didn’t see a mention in the paper on what amount the bump up would be with the maximum amount of AlO2 distributed in the layers of the atmosphere where the reactions would occur. When emissions are in the trillions of tons, I wonder if it would even be measurable.
When emissions are in the trillions of tons, I wonder if it would even be measurable.
emission of what? There aren’t trillions of tons of Chlorine in the stratosphere (that’s what interferes with O3) being pumped into the atmosphere. Are you thinking of CO2?
I doubt anybody can give a confident answer today about the value of the effect that a kg of Al2O3 can have per ton of atmosphere at ozone layer height, because that would involve not just doing what they did in the paper, but also figuring out what “shape” the Al2O3 particles have to know what their adsorption surface would be, for e.g. zeolites this can be 16m2 per gram. e.g. https://www.sciencenews.org/article/earth-extraterrestrial-space-dust-weight-meteorite but maybe it can be simply extrapolated from analogous metallic meteorite dust samples :/
Carbon monoxide also contribute to ozone breakdown, and there are additional manmade substances similar to CFCs with chlorine and bromine that are still leaked. Environmental changes in the Antarctic also can increase ozone depletion as well as longer lasting cold air in the stratosphere (observed in 2020 in the Arctic). The mention of emissions was just to suggest that smaller reactions can get lost in all the other problems we have created, although wildfire increases are raising CO.
Its good to keep an eye out for new sources of pollution, but the possible ozone depletion from satellites burning up is a tiny tiny fraction of what we’re doing on Earth right now for pollutants.
One thing to note - The science is still calculating. Yet. SpaceX (and presumably others) are allowed to continue and increase what they’re doing. This is the bass ackwards way to protect future us.
Its the same mentality as driving in a random direction for 20 minutes while someone looks in the car for the map on the off chance that when you get the map open you’ll be where you wanted to be anyway.
It has the potential (and at this point, just the potential) for planet level changes, and is being done by one group. Should I, a random dude, be able to do something that might possibly affect the entire planet, and the planet as a whole just have to wait and see how it turns out?
The hopeful thought that its probably nothing, before anyone can prove that it’s probably nothing, makes a bet where the short term wins are mine, but any long term losses are everyone else’s.
