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Decluttering low-Earth orbit: It's time to tidy up space
- konschubert 6y agoWe have a nice podcast episode on this topic. We go into a few scenarios on how this might end and how it could be fixed. (You can skip the first 30 seconds of intro) https://www.predictions-podcast.com/2020/03/14/space-debris-bounties-for-dead-satellites/ https://www.predictions-podcast.com/2020/03/14/space-debris-...
- onethought 6y agoIs this really a thing... orbit is a vastly bigger place than the earths surface... you’d have to try pretty hard to hit that junk wouldn’t you?
- nielsole 6y agoon the other hand you move a lot faster than one usually does on earths surface
- Retric 6y agoIf everything on a given orbit it going in the same general direction then their relative velocity is what matters. Collisions are not an issue at geosynchronous orbit for example.
- Fradow 6y agoFrom what you can read on the Internet, yes it appears to really be a thing. Read up on Kessler Syndrome to understand a bit more on the subject. The problem is not just about satellites, but random debris flying unpredictably on orbit. When there starts to be a critical number, the odds to hit something start to raise in the "very possible" territory. The Wikipedia page for Kessler Syndrome even state that, currently, one satellite is destroyed every year by junk. That's only going to increase if nothing is done.
- ehnto 6y agoCheck this site out, it's a catalogue of known stuff in space http://stuffin.space/ http://stuffin.space/ The ISS has regular enough operations required to dodge debris detected approaching for a near miss in space that I think it's definitely a concern for future operations. Consider as well that stuff in orbit is going ~25,000km/h or more and at that speed even a small bolt would decimate a spacecraft on impact.
- 4ggr0 6y agoWhat on earth...I did not know that there are sooo many thing floating around near us. Absolutely crazy.
- onethought 6y agoI always dislike those visualisations as it gives the impression it’s crowded, because the dots aren’t to scale. Are the orbits in opposing directions? If not, then the 25k number isn’t meaningful right? Their relative velocity is what matters That’s interesting about the ISS I hadn’t heard of that as a regular thing.
- onethought 6y agoJust to follow up on the ISS, they have made a total of 20 avoidance maneuverers and they do it if they calculate the chance of hitting as greater than 1 in 10000. So it is a thing, but I wouldn’t call < 1 per year regular
- Cogito 6y agoThe issue is not in passing through the junk - that's like passing through the asteroid belt. We don't (or at least used to not) even plan a specific path through the asteroid belt, as the chance of hitting anything on the way through is so low. The problem is if you want to stay in an orbit alongside the junk. The dynamics of orbital mechanics are interesting, to say the least, but it in no way maps to the surface of some sphere. A somewhat useful analogy is to imagine two circular racetracks, that intersect with each other in two spots. Each racetrack is like an 'orbit', and racecars going around them are satellites. Make the racetracks really big, and put a car on each track. Have the cars drive around non-stop forever. The chance of them hitting each other on any lap is extremely small. However, if you let the cars go for a long time, and one of them completes a lap a little bit faster than the other, the times that they both cross the intersection will slowly get closer and closer together. Eventually, they will crash. If you put more cars on the track, the chance of two of them colliding increases. If everyone time they crash they create lots of baby cars, well you get Kessler Syndrome. This is only a problem for these racetracks because they touch. We protect against this in the orbital world by keeping satellites in different orbits, that don't cross. The problem is that the orbits can shift over time due to gravitaional inconsitencies, and solar flares causing the atmosphere to bleed off into space, and the moon, etc. With lots of long lived satellites in low earth orbit, the chance for a crash increases. But even if we do get lots of baby satellites the other orbits farther out will remain useable (like geostationary orbits), you just have to be a little careful when crossing the low earth orbits on the way out.
- villgax 6y agoCan a large magnetic pulse for a short duration get shards to at least come together & somehow be yeeted down towards earth?
- JulianMorrison 6y agoUnlikely for several reasons. The volume of space is enormous, many shards aren't ferrous, and a magnetic field that intense would damage things on the ground.
- spockz 6y agoI suppose a large blob of magnetic gel might be more useful, attached at the front of a rocket. Magnetic and gel like substance to trap any parts, dust, an debris from collisions.
- detritus 6y agoSounds like a great idea! Although I imagine the size of pulse required would probably be such that it would have some less than desired secondary effects on the upper atmosphere, technologies at ground level and the various early warning systems deployed by our nuclear-armed nations... .
- sampo 6y agoThere's a near-future hard science fiction manga and anime series Planetes, about these cleaning workers: https://en.wikipedia.org/wiki/Planetes https://en.wikipedia.org/wiki/Planetes
- copperwater69 6y agoProbably not a HN tier comment, but there's a great anime about space debris cleanup. https://en.wikipedia.org/wiki/Planetes https://en.wikipedia.org/wiki/Planetes https://www.youtube.com/watch?v=CZ-OyT4ivkM https://www.youtube.com/watch?v=CZ-OyT4ivkM
- teekert 6y agoI also enjoyed that.
- throwaway6734 6y agoFantastic series!
- Cogito 6y agoThis anime is brought up in a lot of threads on space debris, and as others attest is excellent. It's a fully fleshed out and plausible future, where people have jobs cleaning up space debris, and it explores many of the issues that may await that kind of work in the future. Your comment epitomises the golden rule of Hacker News, that you should post "anything that gratifies one's intellectual curiosity".
- AlanSE 6y agoIt was extremely good for its time. For instance, the creators asked scientists to estimate the efficiency of solar panels at the time, and computed the area needed for the space stations they drew. Truly incredible that they went to these lengths. Nonetheless, it is very dated. Fusion power looks a lot worse today than it did back in 2003. The fusion-powered space Jovian exploration ship would be right at home in today's sci-fi (just as much the future today as then), but He-3 as a reason to go into space as been eviscerated. People who still (unrealistically) hope for a fusion game-changer are more often touting proton-Boron, and He-3 doesn't even fundamentally change problems of ignition conditions and radiation, it just mitigates it. They also didn't do much to predict radical reduction in launch costs. In the PlanetES world, it still felt very expensive to get into space. They didn't go unless they had a corporate sponsor or were filthy rich. I don't even remember anything that hinted at booster re-usability, which is now (astonishingly) reality. There's also the obvious fact that sending people to do trash pickup was always more Hollywood than reality. They knew that then.
- immmmmm 6y agocurious of the price of de-orbiting an m6 screw (say m = 4g, v = 8000m/s) given it has the same kinetic energy as a small car (m = 1000kg v = 16m/s).
- hoseja 6y agoYou don't need to get rid of all those 8km/s. Just enough to drop down into the atmosphere, the rest is a shooting star.
- dmckeon 6y agoRemote propulsion by ablation: https://en.wikipedia.org/wiki/Laser_broom https://en.wikipedia.org/wiki/Laser_broom
- immmmmm 6y agoyes, that's the only system that makes sense to me for small objects. with a good international policy that prevents ppl from missiles at satellites to show power and, maybe, also one that prevent ppl to put any crap in LEO now it has got that cheap..
- gchamonlive 6y ago> In the long term, this accumulation of junk may lead to a chain reaction, known as Kessler syndrome, that would make some low-Earth orbits unusable. I read about it, and it seems a little counter-intuitive for me. I would expect that in a collision in space, some of the kinetic energy would be used in internal structural changes, and not all converted to the resulting motion. Am I wrong here? If not, does it still preserve enough kinetic energy after collision to promote this chain reaction? And how long until lower space ring is actually unusable?
- copperwater69 6y agoImagine two objects hitting each other perpendicularly, as opposed to head on. Plenty of momentum could be conserved and thrown out in a median vector. Edit: Not only that, but even if 90% of momentum was lost - it only takes another satellite going in the opposite direction to supply all the energy. Here's what 2 ounces of plastic does at 15,000mph to a block of aluminium. https://imgur.com/gallery/8NwAhgK https://imgur.com/gallery/8NwAhgK
- hiharryhere 6y ago1/2 an ounce (14 grams) according to that link. Even more nuts!
- gchamonlive 6y agoIt depends on the material. If they are flexible, and deform easily, a lot of energy would be converted into structural damage, I would presume. > it only takes another satellite going in the opposite direction to supply all the energy I see, indeed the next collision will supply a lot of external momentum.
- MauranKilom 6y ago> It depends on the material. If they are flexible, and deform easily, a lot of energy would be converted into structural damage, I would presume. At those speeds, everything is "flexible" in the sense that even metal just flows in a fluid-like manner (see picture linked in the comment). Also, the material would have to somehow convert the energy of an entire car crashing into it at full speed. Except the car is only an inch wide.
- Noxmiles 6y agoMeanwhile india: https://en.wikipedia.org/wiki/Mission_Shakti https://en.wikipedia.org/wiki/Mission_Shakti btw: The article is behind a paywall :(
- rocknor 6y agoMeanwhile USA has 25x the debris (as of June 2019). Glass houses... https://orbitaldebris.jsc.nasa.gov/quarterly-news/pdfs/odqnv23i3.pdf https://orbitaldebris.jsc.nasa.gov/quarterly-news/pdfs/odqnv... https://www.businessinsider.in/us-russia-china-and-india-standoff-over-space-debris-after-a-sat-test/articleshow/70837355.cms https://www.businessinsider.in/us-russia-china-and-india-sta...
- Rebelgecko 6y agoI think the concern is that despite increased activity in space, most countries have slowed down the amount of dangerous debris being created. Meanwhile, India created about as much space junk in a day as the US creates in 1-2 years. That's despite claiming that the the test was in an orbit that wouldn't leave any longterm debris.
- AniseAbyss 6y agoEasy to criticize other countries when you've already had your space race. I do find it annoying that space is usually jingoistic bullshit involving flags and rousing speeches instead of actual science. I'm glad ESA never went that way.
- rocknor 6y agoAbsolutely. It's the same in case of climate change, easy to criticize other countries about their emissions when you've already had your industrial revolution. I mean, just look at this graph: https://www.gapminder.org/tools/#$state$entities$show$country$/$in@=usa&=chn&=ind&=gbr;;;;&marker$axis_y$which=cumulative_co2_emissions_tonnes&scaleType=linear&spaceRef:null;;;&chart-type=linechart https://www.gapminder.org/tools/#$state$entities$show$countr... I also agree with your point that sometimes space achievements are used for jingoistic purposes. But if you see the bigger picture (which most people don't sadly) you realize that it is a net positive overall for science and humanity. The jingoistic aspect is just a consequence of political reality.
- tomhoward 6y agoFun fact: A hobby satellite my father helped build as a way to justify procrastinating during university in the late 60s is now low Earth orbit space junk. He says he's rather embarrassed to have learned, post launch, that it would likely remain in orbit for 100,000 years. https://en.wikipedia.org/wiki/Australis-OSCAR_5 https://en.wikipedia.org/wiki/Australis-OSCAR_5 http://centralblue.williamsfoundation.org.au/oscar-5-the-first-australian-built-satellite-michael-spencer/ http://centralblue.williamsfoundation.org.au/oscar-5-the-fir... https://www.youtube.com/watch?v=hjhto6wUQYQ https://www.youtube.com/watch?v=hjhto6wUQYQ
- sandworm101 6y agoYour father's satellite is very high (1400km, 1000km above the ISS) at the edge of what is classified as low earth orbit. It will be up there for a long while but the chance of it ever hitting anything is infinitesimal.
- simonh 6y agoInfinitesimal over 100,000 years? I'm not losing any sleep over it personally, but that's a long time.
- BurningFrog 6y agoYeah, that statement makes a lot of assumptions about the next 99,950 years.
- sandworm101 6y agoThe surface area of the sphere at 1400km is far greater than the earth's surface area. And satellites at that altitude are traveling much slower. Put together, the probabilities would akin to a handful of birds flying on earth, at random altitudes/places/directions, and two of them colliding.
- bagels 6y ago"much slower" is still >7000 m/s
- f-word 6y agoSuppose you put a largeish amount of polyurethane foam in orbit, possibly around some scaffold to take up even more space, had it inflate when up there and had it absorb any wandering garbage for a while. How long would it take for the giant garbage mound to deorbit and burn?
- jl6 6y agoThere’s a lot of junk but it’s spread out over a lot of space. You probably won’t catch much by accident. Also, it may be going dramatically faster than your catcher, in which case it would be less like a mitten catching a ball and more like a mitten catching a bullet.
- f-word 6y agoSure, but there's also a lot of uh mitten in this case, getting progressively denser as more stuff gets trapped in it. I don't think there's that many ways to trap all the tons of hyperfast shrapnel we've up up there, unless we can get starlink to just sporadically throw small nets around in hopes of catching enough junk on any given throw?
- londons_explore 6y agoI suspect if you did the analysis, you'd find rather than it getting denser over time, you'd find most bits of space debris (even tiny ones) would have enough energy to explode your catcher...
- jerf 6y agoNo, your "mitten" is getting blown apart, not getting progressively stronger. Your intuition is not tuned for space. Imagine trying to strengthen a structure by firing extremely high-powered bullets at it. "I have a tree near my house that is about to fall on us... how should I fire my high-powered rifle at it to reinforce it so it stays up?"
- f-word 6y ago
- narag 6y agoWhy "deorbiting"? Considering the cost of putting it there, wouldn't it be better to group the debris in a junkyard? Tell the jawas, maybe they're interested in managing it.
- losthobbies 6y agoMy first thought was the game Hardspace:Shipbreaker https://hardspace-shipbreaker.com/ https://hardspace-shipbreaker.com/
- sandworm101 6y agoWhat people forget is all the natural junk up there. Space is not "clean". Something like 100 tons of rock, mostly dust, falls onto earth from space every day. That isn't stuff in orbit, but given the capture effects of our moon there is likely a significant amount that does achieve some sort of stability. That amount probably outweighs everything we have ever put up there. https://astronomy.com/magazine/ask-astro/2014/07/space-debris https://astronomy.com/magazine/ask-astro/2014/07/space-debri... The real problem isn't that space is getting full of our junk, but that our junk is in a very narrow band of orbits that we use for very specific missions: Sun synchronous polar orbits used by imaging satellites. Look at how these orbits all cross paths at the poles. That's the danger zone. While the military cares deeply about these orbits, civilian infrastructure in space (geosynchronous communications sats, GPS etc) are well beyond any real danger. Or, at least they are in orbits where danger from natural debris is vastly greater than from space junk.
- im3w1l 6y ago> The real problem isn't that space is getting full of our junk, but that our junk is in a very narrow band of orbits that we use for very specific missions: Sun synchronous polar orbits used by imaging satellites. What's the significance of these orbits?
- sandworm101 6y agoA sun-synchronous orbit is a polar orbit where the satellite passes over each part of the earth at the same time every day. That is very useful if you want to photograph things at regular intervals using cameras (stable light, no nighttime) or if your satellite uses solar panels as these orbits can be such that the satellite never falls into the earth's shadow.
- bagels 6y agoThey still go in to shadow once per orbit typically.
- 6y ago
- yottalove 6y agoElon Musk's SpaceX Starlink: thousands of satellites that can be re-positioned en masse in time of need and meanwhile reserve a spot in the LEO surface. Useful in both communication and in denying the space to other classes of satellites.
- gruez 6y ago>and in denying the space to other classes of satellites. Is this actually an issue? The earth has a surface area of 500M km^2 so if want 0.5km between each satellite you can fit 500M satellites at one orbit level. A few thousand spacex satellites is a drop in the bucket.
- Cogito 6y agoRemember that, assuming circular orbits (which is fine for this discussion, I think), you have to fit satellites on great circle paths next to each other. For a single great circle you can fit a significant number of satellites in a chain, but turns out you don't want too many like that as all your satellites cover the same part of the earth. All great circles on a sphere will intersect in two places, which assures a collision if you have satellites in them both (without active avoidance). So you have to separate the great circles on to different sized spheres, or add a little eccentricity to make sure the rings don't touch. There is still a lot of space, but comparing to the size of the surface of the earth is not very informative when dealing with orbital dynamics.
- beerandt 6y agoBut you imply those mitigations must be made to correct the "natural," initial orbital state, when in reality, the orbits were never truly circular or co-spherical. It's not useful to make a simplifying assumption, if the solution to the problem is to reverse the resulting simplifications.
- Cogito 6y agoAfter I finished the comment I almost went back to modify that intro, but figured the gist of it would be ok. What I was trying to do was show how we move from the mental model of dots on a balloon (there is so much space on the balloon! the dots are tiny!) to rings around a ball. In order to make sure the dots don't intersect with each other simply spread them out appropriately. In order to make sure the rings don't intersect each other make some of them slightly bigger, or stretch them a bit. The resulting orbits are still, approximately, great circles on the same sphere - just perturbed a bit.
- williesleg 6y agoYeah it's a coordinated effort against elon musk again, but he'll win again. Can't wait for satellite internet.
- josefresco 6y agoFor other space related content, check out The Orbital Index: https://orbitalindex.com https://orbitalindex.com A nice newsletter about space stuff (I have no affiliation, just a fan)
- deleted 6y ago[deleted]
- environment 6y agoKurzgesagt has made a video about space junk. End of Space – Creating a Prison for Humanity https://youtube.com/watch?v=yS1ibDImAYU https://youtube.com/watch?v=yS1ibDImAYU
- Symmetry 6y agoOne cool way of de-orbiting satellites is to brake against the Earth's magnetic field with a conducting wire. This is actually already a product. https://www.tethers.com/deorbit-systems/ https://www.tethers.com/deorbit-systems/
- flipflipper 6y agoThere were couple demo sats launched a few months ago. One with the tether, one without. https://www.dragracersat.com/ https://www.dragracersat.com/
- PaulDavisThe1st 6y ago> The best idea, though, is to attack the problem at its roots. The littering of space is an example of the “tragedy of the commons”, in which no charge is made for the use of a resource that is owned collectively. Garrett Hardin's article which created and promoted the "tragedy of the commons" doesn't describe historical "commons" at all, which were all managed over extended periods of time by complex rules and social norms. The "tragedies" happened primarily when capitalism emerged and demanded an end to the historical management of commons, allowing the interests of capital to destroy them. Space might actually be the first really good example of "the tragedy of the commons" inasmuch as it was a new, globally accessible (i.e. not geographically determined) resource which began to be used without any establishment of the usual norms and rules that accompanied historical commons. Something similar presumably happened with the oceans, but their physical nature (i.e. stuff sinks, and stuff moves) hasn't created an issue in the same way that is now happening in orbit.
- napier 6y agoWhat we need is a fleet of teleoperated VASIMIR-engined trawlers with electromagnetic fishing nets to clean up space garbage. What about funding? A levy on satellite launches and operators under the polluter pays principle. Perhaps this could be structured as an addition to insurance premiums, considering the purpose is perpetuation of access to Earth orbit and outer space for the sake of future generations and for all mankind.
- TheRealNGenius 6y ago@dang, I thought paywalled articles weren't allowed.
- array 6y agoNon-paywalled version: https://archive.is/GaWcS https://archive.is/GaWcS
- stordoff 6y agoAccording to the FAQ[1]: > It's ok to post stories from sites with paywalls that have workarounds. > In comments, it's ok to ask how to read an article and to help other users do so. But please don't post complaints about paywalls. Those are off topic. I can read the article fine, so I presume there's some level of free access before you trigger the paywall. [1] https://news.ycombinator.com/newsfaq.html https://news.ycombinator.com/newsfaq.html
- dukeofdoom 6y agoStar Timelapse and long exposure night photographers get annoyed by all the current debris, they need to clean up their photos from the light streaks. On the other hand, I remember reading about this town in the mountains that wanted to build a giant mirror on top of a mountain, so that they could prolong daylight in their valley.
- etothepii 6y agoWhen I worked in insurance I'd often discuss satellite debris with our Head of Space. I'd always be told, this isn't something to worry about, since she makes bets on this stuff for a living (admittedly with other peoples money) I'll assume she's right.
- psyc 6y agoGenuinely curious: the insurance industry worries about space?
- Cogito 6y agoIf they are insuring things in or going to space, then yeah! That's exactly what they're paid to do (well the analysts and actuaries).
- etothepii 6y agoYeah my firm has a "Head of Space" definitely the best title in the company bar none. Space premium not our biggest line by any stretch, but the Specialty Re guys write a bit and the team at Lloyd's write quite a lot. Insurance is a fascinating industry ripe for digital innovation. However, sadly, the deals are primarily written based on the quality of your relationships.