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 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.
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
Before anyone jumps on the Anti-Musk train, read the article, please. They admit that they don’t understand the complications that could arise and that they don’t have any hard figures for the damage being caused. I’ll be the first to jump in and say that it’s probably a bad thing to just let metals burn in in atmo, but let’s make sure we discuss the facts, and not just the politics of the potential polluter.
Ah yes, the usual method of waiting until the issue becomes confirmed and also way too severe to fix instead of acting on precaution and harming profits of private companies. What could go wrong?
Yeah, PFAS comes to mind. It took decades to confirm it’s harmful to humans but at this point it is everywhere and hard to get rid of. Worst part is they try to use other chemicals to replace PFAS, but again how harmful they are we don’t know and we will learn that decades later too because companies don’t want to make long term research before releasing the product. Enviroment shouldn’t be a billionaire’s testing ground.
As opposed to acting before you understand the effects of your actions? Neither seem like good choices.
Probably the best option would be to research harder. Make the polluter fund a much larger scale research program to understand the problem and viable solutions as quickly as possible.
Ah yes, the usual method of waiting until the issue becomes confirmed and also way too severe to fix instead of acting on precaution and harming profits of private companies.
No, but as even them don’t understand what the complications are and how much the damages could be, maybe to wait to have at least some hard number looks like a good idea.
What could go wrong?
And what could go wrong if we start to fight a problem that we don’t understand how big it is, maybe using the wrong solution on a wrong scale ?
maybe to wait to have at least some hard number looks like a good idea.
Good plan. So they’re holding off on starlink launches to let the science catch up, right?
Nah, this is a different method. It’s the one where we get all of the facts before we take action. Maybe you aren’t up on it, but knee-jerk is so 1700s.
We don’t have to wait until it’s “fully confirmed” to start being concerned about it. Remember climate change denial? We were in the “we don’t know if humans are causing it” phase for a while.
I also agree, let’s not jump on the anti-Musk team for this, but satellites burning up has always been a rather obvious source of pollution, and it’s good to see more discussion on it
We were in the “we don’t know if we’re causing it” phase for a long time because big oil knew about global warming and deliberately ran disinformation campaigns so they could keep profiteering. Had Exxon done the right thing in the 70s we wouldn’t have this looming crisis.
And now we’re in the “is burning up thousands of satellites bad?” phase of space exploration. I’ll be waiting for spacex to do the right thing.
Don’t get me wrong. I’m not defending corporations here. I’m simply stating the fact that climate change denial wasn’t the case of waiting until it’s “fully confirmed”, it was pretty much confirmed back in the 70s. They even had predictions for the next century on how things will go bad if nothing is done and the last time I checked we were pretty on course with their predictions. When it came to the scientific consensus, it was pretty much “fully confirmed”. It was simply the public opinion where it wasn’t “fully confirmed” because corporations deliberately ran disinformation to make it seem like scientists didn’t know what they were talking about.
But this paper isn’t really confirming anything. The paper itself says that the model does not account for all the factors and to literally quote the paper:
As reentry rates increase, it is crucial to further explore the concerns highlighted in this study.
This paper is not presenting a final conclusion, it’s presenting concerns that need further studies. let’s wait for further studies and if there’s scientific consensus about it being an issue I’m all for bringing out the pitchforks. In the mean let’s keep calm and dread over the doom and gloom that is climate change.
Like maybe wait a few years and finance some science to check that your mega constellation of satellites (built to fail after only a few years to make sure your rocket company never goes out of work) won’t be a fucking nuisance on so many levels before you actually launch them ?
This “get all the facts before taking action” ?Edit: I think I knee-jerked
Oh, you mean a study on the Satellite Internet Constellations that have been in orbit since the 1990s, a full 30 years before Starlink launched? As with nearly everything else, Musk isn’t the first to do whatever he does, he’s just the loudest. If Starlink hadn’t launched we would still be facing the same problems. Thankfully, he’s a big enough ass that he makes a easy target for these kinds of things.
Maybe I didn’t get my facts straight, but iirc there are around 7.5k satellites up there, with starlink current count about 5.5k. And I think I read they got the greenlight for the 7.5k gen 2 sats launches.
That looks like a scale change to me. Associated with the short lifespan (which contrasts with the situation 30 years ago, where launches were more expensive), it’s kind of a new situation and should have warranted a more careful approach.So musk isn’t the first one to launch satellites, I agree. But the way it’s done is kinda new, and mostly on the worse side. And I’m not saying the old way was good, and not absolving previous actors from responsability in the pollution.
Sure, PFAS were also considered a nonsignificant issue until they weren’t, only it’s too late to unfuck it now. Well, no harm in generating more potential ticking time bombs I guess.
I was actually reviewing the O3 depletion process https://en.m.wikipedia.org/wiki/Chlorine_monoxide and Cl only stops reacting with O3 when it ends up as ClO2, but that is rare, because ClO usually is too short-lived to react with another Cl into Cl2O, so it may be possible that a catalyst like Al2O3 could actually clean up Cl interfering with the ozone layer along with the effect of speeding up the nefarious reaction with O3 :D
The irony of a wikipedia expert agreeing with a tabloid skeptic.
Why did you write that? What do you gain or anyone reading from that comment? Who are you performing for? Where is the audience? Are you bored and I’m your little punching bag? If you know, contribute and tell us if and why I am wrong and I will welcome it, if you don’t or it is not worth the effort, just stfu, nobody needs your shit snark.
I wanted to reinforce good behavior, punish bad behavior.
Nah man, that’s just toxic hurtful criticism. Let people brainstorm and just let go of the gavel.
Sure I admit that your mistakes were purely imaginary and we can all pretend you never made them to hide your shame.
If they don’t have grounds to accuse SpaceX then SpaceX can sue them for defamation. SpaceX doesn’t need YOU to defend them.
OP listed the referenced study in the description, it has “hard numbers” from simulations and citations to many other studies as well.
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 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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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.
So… Let me get this straight… The satellites burning up are essentially creating aluminum chemtrails that my mother-in-law keeps going on about?
Thanks Elon
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.
I would put money down the meteorites are below 30% aluminum so I can’t see it being less than doubling.
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 :/
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.
The roughly 10-centimetre-long cube is made of magnolia-wood panels and has an aluminium frame, solar panels, circuit boards and sensors. The panels incorporate Japanese wood-joinery methods that do not rely on glue or metal fittings.
When LignoSat plunges back to Earth, after six months to a year of service, the magnolia will incinerate completely and release only water vapour and carbon dioxide
Huh? I’m confused.
heh, yea, the satellites are not just wood for sure, they goofed. But it’s less metals, which helps.
The article linked at he bottom has a picture and more info on the wooden satellites.
https://futurism.com/the-byte/japanese-scientists-wooden-satellite
This is the best summary I could come up with:
While researchers have largely focused on the pollutants being released by rockets as they launch, we’ve only begun to understand the implications of having thousands of retired and malfunctioning satellites burn up in the atmosphere.
“Only in recent years have people started to think this might become a problem,” said coauthor and University of Southern California astronautics researcher Joseph Wang in a statement.
Since it’s practically impossible to get accurate readings from the kind of pollutants satellites release as they scream back through the atmosphere, scientists can only estimate their effects on the surrounding environment.
By studying how common metals used in the construction of satellites interact with each other, the team estimated that the presence of aluminum increased in the atmosphere by almost 30 percent in 2022 alone.
They found that a 550-pound satellite generates roughly 66 pounds of aluminum oxide nanoparticles during reentry, which would take up to 30 years to drift down into the stratosphere.
“The environmental impacts from the reentry of satellites are currently poorly understood,” the researchers note in their paper.
The original article contains 371 words, the summary contains 176 words. Saved 53%. I’m a bot and I’m open source!
Buy a ticket to mars. Problem solved.
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.
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.
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
