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Potential ozone depletion from satellite demise during atmospheric reentry
- isodev 2y agoVery interesting study. I guess putting things in orbit is absolutely going to cost us but I hope we will have this under control before it gets out of hand. Unfortunately, just like green house gases, it requires the very people who benefit from ignoring these kind of problems to pay attention and well...
- DennisP 2y agoOne of the main reasons we have governments is to solve those sorts of problems. That's how the ozone problem was successfully addressed before.
- hi-v-rocknroll 2y agoThe Montreal protocol worked because it was focused on a limit set of changes. Something similar could also work again if metal satellites and uncontrolled hypersonic reentry spaceship metal parts were outlawed as well. Unfortunately, the lack of a gradual set of limited changes is why the same process cannot be replicated for climate change remediation. Countries are trying to tackle the entire problem as an "impossible" monolith rather than breaking it up into separate industry and lifestyle practices to address incrementally.
- renhanxue 2y agoThe Montreal Protocol was nothing short of miraculous. It was the first international treaty to be ratified by all 198 members of the UN (including the Holy See), and it's been called "perhaps the single most successful international agreement to date" by former UN Secretary General Kofi Annan. It's one of history's greatest achievements of environmental policy and international cooperation. The impact of CFC's on the ozone layer was first proposed in a scientific paper in 1973; the authors testified before the US House of Representatives in 1974 and significant funding was provided to study the problem. The Montreal Protocol was then signed in 1987 despite industry protests that the research was uncertain and there was no crisis that demanded urgent action. This was only 14 years (!) after the effect was first hypothesized. The discoverers of the effect won the Nobel Prize for chemistry in 1995. I don't expect to see anything even remotely as successful as the Montreal Protocol in my lifetime.
- padjo 2y agoEspecially when people now think the ozone hole was a hoax and use that as justification for doing nothing about co2 emissions
- defrost 2y agoSome people ... You might as well say people now think { vaccines are clot shots | earth is flat | 9/11 was an inside job } and use that as justification to do nothing about AGW.
- wkat4242 2y agoI've heard the same said about acid rain. Another case of an actual major problem that was quickly solved by multilateral action. People don't understand that those problems were peanuts though in comparison.
- boxed 2y agoI would have liked an estimate of the natural sources to compare.
- martinclayton 2y agoIt's in section 3.3. - Natural Al estimated at 141.1 metric tons / year not varying. - Human-made: 2016: 5.36 tons, 2022: 41.7 tons, "future" could be 912 tons, i.e. more than 6x natural. I think the last figure is based on many planned large satellite constellations being deployed.
- golol 2y agoIf aluminum is the issue, could steel and plastics be a solution? Especially with Starship coming online, weight should be less of an issue.
- justin66 2y agoAnything’s possible but the mass of the satellite won’t cease to be something they need to optimize, even with a heavier booster. Those little satellites use thrusters themselves when they’re in orbit.
- ginko 2y agoThere's also magnesium alloys, but if MgO is any better in the stratosphere is anyone's guess
- dylan604 2y agoThere's a lot of really smart people that understand chemistry at a much better level than the typical reader on an internet forum. Do we really need to "guess"? Seems like we could study this to actually determine what would happen with controlled experiments. One might go so far as to call that the scientific method.
- s1artibartfast 2y agoNope, it is unknowable because ginko doesnt know /s
- kortilla 2y agoThe thrusters are to offset atmospheric drag, which accumulates with surface area, not mass.
- justin66 2y agoWeird half-true comment. Imaging satellites change their orbits, satellites operating in constellations station-keep, etc.
- adrian_b 2y agoThe Japanese have already been concerned by this problem for a few years. Their solution has been to develop satellites made mostly of wood, which will burn completely upon reentry. The first such wooden satellite is planned to be launched in September. It is intended mainly for collecting data about the behavior of wood in the outer space, e.g. on wood expansion, contraction and degradation, along with internal temperature and electronic equipment performance. An alternative to wood would be the use of synthetic polymers, but those are typically more sensitive to radiation, so more research would be needed for finding a suitable plastic and appropriate additives to decrease the radiation sensitivity. Wood or plastic would not be suitable for ships hosting humans, because they are not hermetic, but they may be an acceptable choice for satellites with a short lifetime and with much more relaxed constraints for the composition and pressure of the internal atmosphere (which may not be needed at all, e.g. when the internally produced heat reaches the external radiant cooling surfaces through solid paths or through pipes with circulant liquid).
- elil17 2y agoThat would be so awesome! Reminds me of the sci-fi book “Children of Time”
- IshKebab 2y agoWhat about something like carbon fibre?
- dr_orpheus 2y agoIt is used quite a bit in the space industry already. But it is more expensive so it is usually confined to applications where you really need the weight savings, or you need something with a more controlled coefficient of thermal expansion. Thermal expansion of carbon fiber is small so you get less mismatch when you use it with things like optics or as part of solar panels. And a common place you find carbon fiber in the space industry is actually carbon fiber skinned aluminum honeycomb panels. Very light and very stiff. https://www.rockwestcomposites.com/shop/plates-panels-angles/sandwich-panels/honeycomb-core-sandwich-panels https://www.rockwestcomposites.com/shop/plates-panels-angles...
- jl6 2y agoI couldn’t see a quantitative estimate of how much ozone would be depleted in a typical year as a result of the extra catalyst being present. If it’s only ~hundreds of tons, that seems both immaterial (there are about 3 billion tons of ozone in the atmosphere currently) and potentially easy to replace (fly up there and dump some fresh ozone).
- gmm1990 2y agoI think it says its a catalyst, for some chlorine reaction. So its not out of the question 300 tons (per year) could effect ozone concentrations.
- marcosdumay 2y agoThere's absolutely no estimation of the impact. Your 300 tons of activated chlorine per year idea is as baseless as the GP's 300 tons of ozone, but the GP is aware that his number is a complete invention. Any exercise in making numbers out of nothing is completely useless. (Besides, is chlorine activation really a bottleneck in ozone depletion? AFAIK it gets activated by UV light quite quickly.)
- gmm1990 2y agoGP never implied the amount of ozone just the amount of aluminum oxide. All I know is catalysts can speed up reactions by orders of magnitude. CFCs actually created a hole in the ozone layer so its not like human activities haven't accidentally created problems before. Probably something that at least needs to be ruled out.
- deleted 2y ago[deleted]
- oasisbob 2y agoCorrect. That's the same way I read that comment. More fundamentally, chemical catalysts by definition are not consumed by the reactions they catalyze. Think: a cheese grater. It doesn't react with the cheese, so a few ounces of grater could make hundreds of pounds of grilled cheese. A hypothetical 300 tons of catalyst is not limited stoichiometrically to how much substrate it would affect.
- pwndByDeath 2y agoI'm no chemist but I noticed this other researcher wanted to dump literal tons of another oxide into the atmosphere to counteract global warming. https://iopscience.iop.org/article/10.1088/1748-9326/aae98d/meta https://iopscience.iop.org/article/10.1088/1748-9326/aae98d/...
- elil17 2y agoAn oxide is just a molecule with one oxygen atom and one other element. Different oxides would have different effects on atmospheric chemistry.
- astrodust 2y ago"Nitrous oxide best oxide." -- Dominic Toretto
- gravescale 2y agoAs a lifelong addict, I literally cannot live without my regular dihydrogen oxide. Even a day without is painful.
- dmbche 2y agoSee "Snowpiercer"
- selimthegrim 2y agosee https://news.ycombinator.com/item?id=37344251 https://news.ycombinator.com/item?id=37344251
- datameta 2y agoTo geoengineer or not to geoengineer, that is the question. Can we build models that six nines assure us of a small stable improvement that stays near linear behavior, or asymptotic better yet?
- deleted 2y ago[deleted]
- londons_explore 2y agoOne option is to make the satellite survive re-entry rather than burn up. Then just re-enter over a desert like australia or the sahara so you can go find and collect the junk. Single-use heat shields for smallish things like satellites are quite easy I believe, although fold-out items like solar panels would need to be designed to fold-in again.
- arresin 2y agoIt’s not all desert here mate.
- bh1shma_pitamah 2y ago[flagged]
- ferfumarma 2y agoPlease fine the companies who did this. This is a global problem that affects everyone, but especially those of us in Australia.
- pdabbadabba 2y agoJust so you know, the comment immediately below yours proposes a solution where satellites are designed not to burn up at all and are aimed at Australia during reentry. > One option is to make the satellite survive re-entry rather than burn up. Then just re-enter over a desert like australia or the sahara so you can go find and collect the junk. So be careful what you wish for!
- idiotsecant 2y agoParent post: won't someone please think of Australia!!!! Global military industrial complex: Now that you mention it...
- Culonavirus 2y agoManufactured outrage.
- hi-v-rocknroll 2y agoMaybe or maybe not. I want to know what "significant" means in terms of stratosphere effects in DU/km^2 per kg of aluminum oxide.
- ck2 2y agoPrivatize the profit (and government helps pay for development) then socialize the cleanup costs. Why doesn't every messy industry like this have to pre-pay massive insurance fees ahead of time for known and unknown damages? Note X isn't the only one with thousands of satellites, there are several startups that are launching their own thousands. Soon we'll have debris and burnup of dozens a day, that will add up.
- mathsmath 2y agoIt's kind of like the industrial revolution. I don't think anyone knows what will happen (it's the classic human behavior of kicking the problem down the road), but the collective human mind has decided we want global connectivity now that it's cheap. I can't see the cat going back into the bag (or reengineered) unless there have been proven negative results like the ozone hole directly linked to CFCs.
- aaron695 2y ago[dead]
- selimthegrim 2y agoOther work on this from January but focusing on temperature in stratosphere: https://arc.aiaa.org/doi/abs/10.2514/6.2024-2169 https://arc.aiaa.org/doi/abs/10.2514/6.2024-2169
- sandworm101 2y agoHow about just not letting them burn up? Give the core an organic heatshield (wood?) and let it crash into the ocean. Even thousands of them each year would be nothing compared to the amount of waste regularly dumped into the oceans, an acceptable compromise over ozone depletion.
- BurningFrog 2y agoIf thousands of intact satellites crash to Earth yearly, they will hit and kill people, even just over the oceans. People will also be upset about the environmental damage, real or imagined.
- sandworm101 2y agoThousands of small rocks fall from space every year, have done so for a very long time. Human deaths are almost unheard of.
- mathsmath 2y agoNot only this, but they fall in a randomly-distributed fashion. Most satellites are still under control and steered to a predetermined area for reentry over the South Pacific.
- dr_orpheus 2y ago> Most satellites are still under control and steered to a predetermined area for reentry over the South Pacific. This is not true, most satellites do not perform controlled re-entry. In order to perform controlled re-entry, you need to have enough thrust to perform the final de-orbit maneuver in a short amount of time before you get so low that you start to lose attitude control of the spacecraft and wouldn't be able to guarantee you are firing your thrusters in the correct direction. To do this in a short amount of time means you need a high thrust system, in other words a chemical propulsion system and not electric propulsion. All of the Starlink satellites use electric propulsion to do their de-orbit so they are performing uncontrolled re-entry. NASA's Orbital Debris Mitigation Standard Practices (ODMSP) say that you can perform uncontrolled re-entry if the probably of casualties on the ground is less than 1 in 10,000. There are NASA analysis tools that are used to do that assessment of what kind of debris would survive re-entry. This is likely getting updated in the near future to be more conservative though as there was recently a piece of an old ISS battery they thought would burn up hit someone's house in Florida: https://spacenews.com/uncontrolled-reentry-of-space-debris-poses-a-real-and-growing-threat/ https://spacenews.com/uncontrolled-reentry-of-space-debris-p...
- will1am 2y agoI think as we continue to expand our use of space, it is crucial to consider the environmental impacts!
- deleted 2y ago[deleted]
- LeifCarrotson 2y ago> We find that the population of reentering satellites in 2022 caused a 29.5% increase of aluminum in the atmosphere above the natural level, resulting in around 17 metric tons of aluminum oxides injected into the mesosphere... On the scale of the planet, that's incredibly tiny. 17 metric tons of aluminum oxide can be made by oxidizing a cube of aluminum about 1 meter on a side. The catalytic action must be incredibly potent! Wolfram helpfully tells me that the mass of the mesosphere is on the order of 10^12 tons, so that's on the order of parts per trillion.
- shadowgovt 2y agoIt's tiny, but it may be enough if the wind currents are concentrating it, as happened with CFCs doing away with the ozone layer over the South Pole.
- ls612 2y agoIt’s tiny compared to the mass of natural debris which enters the atmosphere as well. This is just SpaceX NIMBYism tbh.
- yourMadness 2y agoIs there even an estimate of the impact on ozone in the paper? You don't need a science paper to end up with "letting satellites burn up in the atmosphere results in burned satellite dust in atmosphere", do you?
- briandw 2y agoSpaceX put up 1,238 tonnes in 2023. So let's say about 2000 tonnes globally. I don't know the Al fraction of a satellite, but assuming it's very high. Estimates are 15,000 to 220,000 tons of meteoritic material entering earth annually. Assuming 1.2% Al in a meteor (from the paper) that's 180 to 2604 tons of Al. So the range of human impact is somewhere from 2 to 10 times the meteoritic material in Al. That's quite surprising, assuming that my math and research is correct. Switching to steel should make the environmental impact negligible, considering that the Fe content of meteorites is quite high. meteoritic material source: https://adsabs.harvard.edu/full/1994IAUS..160...45B https://adsabs.harvard.edu/full/1994IAUS..160...45B
- mhio 2y agoSwitching to steel means satellites don't demise and hit the ground in larger chunks, something that the FCC has actively avoided in their constellation licensing for fear of hitting things. For example the 4 reaction control wheels for attitude adjustment where you actually want mass, were specifically moved to Al on starlink so that they _would_ burn up on reentry. I don't know how you weigh the risk of environmental effects vs occasionally landing a sat on something, or someone. I guess an actuary somewhere has a table for that.
- everforward 2y agoI would think it depends heavily on the degree of control they have over where it lands, which is perhaps something that could be optimized for? I still think it’s a political non-starter, though. People will be terrified of being randomly struck with a satellite, and it would be an enormous international crisis if an American satellite deorbited and took out a skyscraper in Beijing or vice versa. Heaven forbid one accidentally hits the Pentagon or similar, it would probably start world war 3.
- mhio 2y agoIt would be interesting to see if the current constellation reentries are in any way grouped over specific areas. My understanding is spacex don't have exact control due to the relative weakness of the ion thrusters and the unpredictability of aerodynamic drag on the big flat surfaces (1). Say only 1% of reentries were completely uncontrolled and random then you're right, that could shift the odds from just acceptable to meh. (1/10.000 -> 1/1.000.000) 1 - https://api.starlink.com/public-files/technology_v2mini_backup_carousel_d.webp https://api.starlink.com/public-files/technology_v2mini_back...
- QuadmasterXLII 2y agoCosmic dust dumps about 30 tons a year of aluminum into the atmosphere already