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Japan developing wooden satellites to cut down on space junk
- deleted 6y ago[deleted]
- powersnail 6y agoI don't know satellites at all, so bear with me if I'm being too naive. Would it be feasible to put a self-destructive program in each satellite, such that when it retires, it moves off the orbit away from the earth, and spirals away?
- anchpop 6y agoNo, it takes a lot of energy to get out of orbit. But unless the satellite is in a few very special locations in Earth's orbit, its orbit will naturally decay over time and eventually fall back to Earth, usually burning up in the atmosphere. (Above low-earth orbit this could take a very long time, but now satellites are required to be designed with deorbiting in mind) Often some parts of the sat still make it to the ground, but SpaceX's Starlink sats for example are designed to fully burn up in-atmosphere within a year of deorbiting.
- throwaway-8c93 6y ago> No, it takes a lot of energy to get out of orbit Does it? It takes ~10000 m/s of delta-v to reach low Earth orbit, but afaik only about extra ~30 m/s to deorbit, with aerobraking taking care of the rest of the velocity. Or is there any extra intricacy in the details?
- cyphar 6y agoThey were talking about escaping orbit (reaching escape velocity which is ~41% higher than the orbital velocity and requires getting more fuel into orbit), not degrading the orbit so that the satellite burns up in the atmosphere. As the article discusses, the latter has the flaw of putting alumina particles in the upper atmosphere which remain there for many years.
- jvzr 6y agoI'm pretty sure parent meant "escape Earth's orbit", not "deorbit"
- Symmetry 6y agoOrbital decay depends on a satellite's particular orbital height to a huge extent. A satellite orbiting 250 km up might come down in a week. The same one at 500 km might take centuries.
- wintorez 6y agoMoving off the orbit is not as easy. You basically have to slow down in order to de-orbit, and that requires rockets. These end of life rockets adds to the weight of each satellite which adds to the cost of launching them.
- buran77 6y agoThe problem that wooden satellites would address is space junk falling to Earth and aluminum burning up on reentry, leaving particles in the atmosphere: > We are very concerned with the fact that all the satellites which re-enter the Earth's atmosphere burn and create tiny alumina particles which will float in the upper atmosphere for many years
- ratsforhorses2 6y agoWhat about little drones that pushed them out of orbit?
- ratsforhorses 6y agohttps://www.hindawi.com/journals/jchem/2019/4753910/ https://www.hindawi.com/journals/jchem/2019/4753910/
- Rebelgecko 6y agoThere's some interesting work that's been done with using electromagnetic tethers to deorbit
- vagrantJin 6y agoThis is interesting. Cant we automate this and have drones tether the debris? It could launch from the ISS by mechnical propulsion (throw that bad boy with a mechanical arm)
- Rebelgecko 6y agoThe ones I've seen are mostly intended to be installed on cubesats as a primary or backup method of deorbiting. However if it works well I suppose they could also be put onto little probes that latch onto problematic debris. Dunno if that's cost effective
- andreareina 6y agoAssuming you don't mean to literally blow up the satellite, unless you have enough fuel to boost the satellite to earth escape velocity (expensive), it's not going to "spiral away" but get boosted to an elliptical orbit where the highest point ("apogee") is going to be at a higher altitude, but the lowest point ("perigee") is still going to be the same low altitude it started from. You could do a second burn at apogee to circularize the orbit and thus keep the satellite at that altitude all the time, but that's more fuel again. IIRC per a video by Scott Manley they do this for geostationary satellites and maybe at medium orbits, but for low-earth orbits (the majority of satellites) the extra fuel requirement goes against the cost advantage of LEO.
- kolinko 6y ago+1 - delta v is what matters, and a regular explosive would not throw a satellite off orbit significantly. But this makes me wonder - what is the minimum possible size for a nuke? I wonder if say 1-2kg nuke would be enough to throw all the debris out of orbit...
- wongarsu 6y agoNo matter how you explode it, turning one piece of debris into many pieces at even higher velocities is only making things worse.
- KMag 6y agoTo add to this, given what we're learn about nuclear weapons in school/media, you'd think a small fission device would convert the entire mass of the satellite into a ball of mixed plasma and vapour. A lot of the non-metallic mass of the satellite would probably vaporize, but any surviving bits would have a bunch of added kinetic energy. Especially for things that reflect both infrared and soft x-rays, with pretty high melting points and pretty high thermal masses, nuclear explosions do less damage than you'd think. There was a nuclear test where they put a steel sphere about the size of a bowling ball pretty close to a device similar to Gadget / Fat Man. Spoiler alert: it survived barely scratched.[0] You could probably design a satellite with thin enough pieces of metal and add carbon black / carbon fiber to any polymers too transparent to IR/soft x-rays. You could probably also use a thermonuclear device, but the particle steams caught in the earth's magnetic field would damage satellites, and there's also the EMP to worry about. [0] https://www.youtube.com/watch?v=by1xpy8ob8E https://www.youtube.com/watch?v=by1xpy8ob8E
- Fordec 6y agoGraveyard orbits for GEO, and forced atmospheric drag for LEO. Now, what happens if the propulsion is broken? Or out of fuel. Or the drag mechanism failed to deploy? How does any sophisticated deal with the physical reality of it not being able to move itself? Self retirement assumes the happy path that everything goes according to plan without breaking in a radiation rich environment moving at thousands of km per second.
- m4rtink 6y agoThe space debris section will have to pick it up manually: https://en.m.wikipedia.org/wiki/Planetes https://en.m.wikipedia.org/wiki/Planetes
- Fordec 6y agoOne of my top three favorite shows ever. Still the standard I hold hard sci-fi to for doing the space environment right. Even if it's a bit dated on it's Japanese work place love interest plot.
- dwightgunning 6y agoEven if it were feasible... it seems like it would just defer the problem to a later time or place the burden on other intergalactic citizens.
- adrianN 6y agoSpace is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space.
- saargrin 6y agoit would be easier to have it spiral into the atmosphere and burn up i mean thats what happens to most satellites anyway
- MaulingMonkey 6y agoEscaping earth's orbit is expensive. Much cheaper in mass/payload/$$$ to simply deorbit and burn up for a lot of low earth orbit satellites. Or even "free" - a lot of these satellite megaconstellations will be brought down by atmospheric drag within a year of running out of fuel: https://en.wikipedia.org/wiki/Graveyard_orbit#Disposal_orbit https://en.wikipedia.org/wiki/Graveyard_orbit#Disposal_orbit This also provides some passive decluttering of low earth orbit in case of hardware failures and the like. Such self destruct programs (or manual commands from a ground station) are common for farther out orbits like geostationary, although they typically just enter a slightly different orbit where they're out of the way and not taking up valuable real estate in particularly useful orbits, instead of escaping earth's gravity or deorbiting completely.
- geocrasher 6y agoAs usual, Scott Manley has an excellent video that discusses spacey things. This one is about Graveyard Orbits: https://www.youtube.com/watch?v=ruf_mfjOt9k https://www.youtube.com/watch?v=ruf_mfjOt9k
- teruakohatu 6y agoI don't really understand why wooden junking floating around space is any better than plastic. Microbes won't be able to break it down like they would on earth.
- beprogrammed 6y agoThe article mentioned that small aluminum particles are left in the upper atmosphere after burning up. The wood would presumably not have this problem.
- deleted 6y ago[deleted]
- elric 6y agoGiven the rich and intricate technical history of Japanese carpentry, it's not surprising that they're the ones pushing this forward. If you search for "Japanse joinery", you'll be in for a mesmerizing treat of intricacy.
- vagrantJin 6y agoChinese carpentry is just as if not more intricate. As someone who does small carpentry projects, watching a bunch of guys build a house with wood and not a single nail is like watching pornography for the first time. The dedication to craft and tool is truly mesmerizing.
- contingencies 6y agoAFAIK the Japanese benefited from significant joinery knowledge from China circa the Nara period (~700CE). In Japan they rebuild temples regularly using these techniques and have thus kept them alive, and also have old standing examples. However, China lost most examples in the cultural revolution. I have visited what was at the time allegedly the oldest dated example in southern China, a temple north of Ningbo, and while impressive it is nothing on what's in Japan. That said, this is more about material science than joinery.
- aasasd 6y agoWith the Sony Clie PDA came a software disc, and it was in a slim ‘jewel’-case box that had the cd tray slide out from the side—and not slide out entirely but hold at the last inch or so. The box was made entirely from cardboard, except for the standard plastic piece that held the disc by the center hole. That's when I knew the Japanese take their origami seriously.
- saargrin 6y agohow does that solve anything? getting hit by a chunk of wood at orbital speeds is pretty much the same as getting hit by same mass of ice or rock ..
- hotgeart 6y agoThat's not the goal... "We are very concerned with the fact that all the satellites which re-enter the Earth's atmosphere burn and create tiny alumina particles which will float in the upper atmosphere for many years,"
- WalterBright 6y agoIt isn't the same. The density matters. A less dense object will spread the force of the impact over a larger area. It may be enough to result in deformation rather than puncture. The reason knives cut is they concentrate the force over a very small area.
- Symmetry 6y agoAt a 10 km/s orbital encounter even a dry sponge will have no problem penetrating the metal hull of a spacecraft, both will turn to plasma. This is what a collision with a 7 gram object does[1], a sponge is about 100 grams and it's softness won't matter when it's traveling at hypervelocity. [1]https://en.wikipedia.org/wiki/International_Space_Station#/media/File:SDIO_KEW_Lexan_projectile.jpg https://en.wikipedia.org/wiki/International_Space_Station#/m...
- bigbubba 6y agoTornadoes have been known to embed bits of straw or dried grass into trees. And tornado speeds are a gentle walk in the park compared to orbital speeds.
- BorisTheBrave 6y agoSo, this does nothing to actually combat space junk in the sense of debris in orbit. The actual goal is: > We are very concerned with the fact that all the satellites which re-enter the Earth's atmosphere burn and create tiny alumina particles which will float in the upper atmosphere for many years
- jessriedel 6y agoRight. The author is clearly conflating orbital debris with re-entry pollution. It is baffling to me that the BBC, a fairly respectable organization, allows this sort of terrible journalism. The author clearly does not understand the subject matter at all, which is not surprising since he's a business reporter regurgitating (presumably) a press release from a university and/or a forestry company.
- HPsquared 6y agoGell-Mann Amnesia, as described by Michael Crichton: “Briefly stated, the Gell-Mann Amnesia effect is as follows. You open the newspaper to an article on some subject you know well. In Murray's case, physics. In mine, show business. You read the article and see the journalist has absolutely no understanding of either the facts or the issues. Often, the article is so wrong it actually presents the story backward—reversing cause and effect. I call these the "wet streets cause rain" stories. Paper's full of them. In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.”
- ralusek 6y agoThe year is 2132, and with the eradication of cancer, Japanese space splinters move into position of the leading cause of death in humans.
- helsinkiandrew 6y agoConsidering these are full of electronics, power sources and other metal 'things' - do they really reduce the amount of particles reduced into the atmosphere by much? And how much of an issue is aluminium particles from burnt out satelites in the atmosphere anyway?
- ajkjk 6y agoI normally agree with this kind of skepticism but doesn't it obviously reduce the number of metal particles by exactly the amount of material that you converted to be made of wood?
- rundmc 6y agoSo there is 3,600 piles of precious metals floating around up there. How long before someone builds a space drone to snare that bounty?
- sacred_numbers 6y agoOnce we start building things in space (beyond assembling pre-built modules) it might be worthwhile, although even then it might not be worth it, since it would take a lot of fuel to move from orbit to orbit catching dead satellites. In orbit fuel is approximately just as precious as metal, so any satellite-catching drone would have to be extremely fuel efficient.
- KineticLensman 6y agoWooden missiles are a thing too, or at least partially wooden. The WW2 German Rheintochter [0] surface to air missile had beautiful wooden control surfaces. https://en.wikipedia.org/wiki/Rheintochter https://en.wikipedia.org/wiki/Rheintochter
- bigbubba 6y agoSimilarly, the Japanese Type 91 aerial torpedo was sometimes equipped with wooden aerodynamic stabilizers (which broke off when they hit the water.)
- lmilcin 6y agoUmm... I don't get it. There is much more natural matter entering our atmosphere by way of dust and meteorites. This one says about 40 thousand tonnes each year: https://skyandtelescope.org/astronomy-resources/astronomy-questions-answers/has-anyone-calculated-the-combined-tonnage-of-meteroids-and-space-debris-falling-into-our-atmosphere-yearly/ https://skyandtelescope.org/astronomy-resources/astronomy-qu... Granted, not all of this is aluminium but I can imagine there is more metal raining down than all man made satellites combined. As to space junk which is matter floating on specific orbits around Earth, it does not matter much what it is composed of. If they hit each other at multiple kilometers per second it doesn't matter if it is made of wood, paper or steel. The result is from kinetic energy being released, not the composition of the bodies. I think the goal should be to make less satellites, smaller ones and maybe also built in a way that would make them less prone shattering into multiple small parts if hit. Less satellites -- satellites should be shared. We shouldn't be in a position where every company that decides to send thousands of satellites can do so at will. I think the number of satellites at various orbits should be limited and controlled the same way the electromagnetic spectrum is being controlled for common good. For this reason we should think how we can make as many possible uses with small amount of satellites and this I think should include some sharing schemes (the same way we share EM spectrum). Smaller == less cross section for collisions, less matter spread in case it collides. Less prone to shattering == further prevents or slows down any chain reactions from part of one satellites hitting another satellites.
- 14 6y agoMy brow raised when you said the share word. I just don’t see it happening because people are greedy. And then the minute some small country decides it wants to enter the space will they be allowed? How will space be allocated to players late in the game is what I am asking?
- istinetz 6y agoAnd what about countries such as Iran? Somehow I prefer a world with lots of space junk over a world in which the US effectively controls who gets access to space. I honestly can't imagine an international organization that is fair in the least in allocation of space trajectories. See the UN, WTO, WHO, the Worldbank... No thanks.
- JoeAltmaier 6y agoDoesn't smoke also float around in the atmosphere for years? Is it significantly different from alumina dust?
- tartoran 6y agoA large inverted cone could deflect space debris and junk off the orbit and towards earth. I don’t know how this feat could be executed though, maybe in the future when it will get cheaper to bring stuff into the obit a few cones like this could begin a cleanup stage.
- bagels 6y agoI don't think the physics are on your side on this one.
- JoeDaDude 6y agoThis might be a good time to watch the movie made by the ESA about responsible satellite disposal. https://www.youtube.com/watch?v=zT7typHkpVg https://www.youtube.com/watch?v=zT7typHkpVg
- gioscarab 6y agoWood is a very good heat shield and was used by China at the start of their space program when composite material was beyond their manufacture abilities. What they will likely achieve is to preserve what is inside the wooden box during re-entry and rise the chances of hitting something and cause damage.
- cbanek 6y ago> During this mission, he became the first person to throw a boomerang in space that had been specifically designed for use in microgravity. Okay, you've won me over. This is awesome.
- webwielder2 6y agoRussian Scientists Announce Six-Month Delay In Carving New Space Station: https://www.theonion.com/russian-scientists-announce-six-month-delay-in-carving-1819564767 https://www.theonion.com/russian-scientists-announce-six-mon...
- africasiaeuro 6y agoNeither do I get it. All are wiring and electronics made of wood too. Or how about a tear drops in all oceans combined.
- giantg2 6y agoWouldn't carbon fiber be a good candidate for replacing aluminium? It would burn up and result as carbon in the atmosphere similar to the wood, but should be more environment insensitive and probably lighter weight.
- samizdis 6y agoArstechnica article: [BBC] Coverage of “wooden satellites” misses the point https://arstechnica.com/science/2020/12/wooden-satellites-an-intriguing-idea-but-wont-solve-space-junk-problems/ https://arstechnica.com/science/2020/12/wooden-satellites-an... Edited to add [BBC] in title, to indicate that the Ars piece is a reaction to, and critique of, the Beeb's article.
- blackrock 6y agoWhat hurts more? Slamming into a 10 pound block of wood? Or a 10 pound block of metal?
- novia 6y agoSumitomo Forestry released a press release in Japanese [1], and Google Translate works pretty well on it. Additionally, there's an English version of the Japanese news coverage [3]. The main points I've seen when looking through these resources are: - Wood is a renewable resource, unlike all these metals we keep burning in the atmosphere - Electromagnetic waves are not blocked by wood. Because of this, if the proof of concept works out, astronauts will be able to keep all their communication equipment, like antennas, on the inside of the ship. - When wood burns it decomposes into gases you would already expect to find in the atmosphere. - The goal is to find something to increase the price of wood. Basically, this is a fishing expedition. - Even if this doesn't work out, the research might lead to some new applications for wood. - The project name is LignoStella and the satellite will be called LignoSat. [1] https://sfc.jp/information/news/2020/2020-12-23.html https://sfc.jp/information/news/2020/2020-12-23.html [2] https://univ-journal.jp/74704/?show_more=1 https://univ-journal.jp/74704/?show_more=1 [3] https://asia.nikkei.com/Business/Science/World-s-first-woode https://asia.nikkei.com/Business/Science/World-s-first-woode...