[HN Gopher] Chinese villagers capture video of falling Long Marc...
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Chinese villagers capture video of falling Long March rocket
booster [video]
Author : DamnInteresting
Score : 166 points
Date : 2023-12-27 16:56 UTC (1 days ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| wildekek wrote:
| Hypergolics in your backyard is no joke.
| meepmorp wrote:
| A little UDMH never hurt anyone. Well, not for very long at
| least.
| duskwuff wrote:
| "Orange smoke. Don't breathe this."
|
| (The color is characteristic of nitrogen dioxide, which is a
| breakdown product of many hypergolic propellants.)
| ethbr1 wrote:
| As wise words now as the days they were spoken. Never forget
| the eternal question: will it blend?
| cocostation wrote:
| Reminds me of when a crewed SpaceX capsule landed in the Gulf
| of Mexico near Pensacola and a bunch of idiots in boats went to
| check it out.
|
| https://www.space.com/boaters-crash-spacex-crew-dragon-splas...
| Simon_ORourke wrote:
| This kind of event is highly irresponsible, and let's be clear
| their space program decided for it to fall in or around where the
| video was taken. Utterly reckless.
| londons_explore wrote:
| In this case that recklessness paid off... Nobody was killed or
| injured, and they probably gain far more from being able to
| inspect the used booster than the cost of cleanup/replanting a
| tree or two.
| Thorrez wrote:
| It looks like it exploded when it landed. How inspectable
| will it be?
| dh2022 wrote:
| The fact that nobody was injured does not make it any less
| reckless...
| abracadaniel wrote:
| Does spreading incredibly carcinogenic compounds in a
| populated area count as injury?
|
| https://en.wikipedia.org/wiki/Hypergolic_propellant#Disadvan.
| ..
| elsonrodriguez wrote:
| This line of reasoning is often heard on a crowded lake after
| a close call with a boat.
| mynameisnoone wrote:
| It's the reasoning of Idiocracy / Darwin Award candidates.
| perihelions wrote:
| - _" Nobody was killed or injured"_
|
| We have no possible way of knowing that, given this is
| Communist China with a press-freedom index of approximately
| -[?], and a *documented history* [0] of concealing and
| covering up politically-inconvenient mass casualty events,
| including, very specifically, government rocket boosters
| landing on civilians.
|
| [0] https://en.wikipedia.org/wiki/Intelsat_708
|
| - _" The nature and extent of the damage remain a subject of
| dispute. The Chinese government, through its official Xinhua
| news agency, reported that six people were killed and 57
| injured. Western media speculated that between a few dozen
| and 500 people might have been killed in the crash; "dozens,
| if not hundreds", of people were seen to gather outside the
| centre's main gate near the crash site the night before
| launch.[4] When reporters were being taken away from the
| site, they found that most buildings had sustained serious
| damage or had been flattened completely.[4] Some eyewitnesses
| were noted as having seen dozens of ambulances and many
| flatbed trucks, loaded with what could have been human
| remains, being taken to the local hospital.[4]"_
| Tommstein wrote:
| Is it just me, or does the booster disappear shortly before
| hitting the ground, followed by the explosion happening before
| the now invisible booster should've hit the spot of the
| explosion?
| gedy wrote:
| It's just end is pointing towards camera in the last moments
| Tommstein wrote:
| That would explain half of it, although I looked for that and
| couldn't see it. Wouldn't explain the other half though.
| ChrisClark wrote:
| No, I see it fall right to the ground and explode at the moment
| it hits the ground.
| traviswingo wrote:
| I've had people look at me like I'm crazy when I say that the
| A.I. that will be a threat to humanity will be of Chinese origin.
| It's this exact "succeed, at any cost" mentality that cements my
| belief.
| dylan604 wrote:
| strange comment for this particular video. not really sure what
| a rapid disassembly of a rocket has to do with AI.
|
| i don't disagree though, maybe for differing reasons
| throwup238 wrote:
| The boosters should have their own flight termination system
| which should have exploded if they were going to fall
| anywhere near populated land. Everyone in the US has to have
| them even if they're launching from Florida over the ocean
| and each independent flight component (like rocket boosters)
| has to have its own.
|
| Allowing a rocket to fall on land like that shows extreme
| contempt for public safety.
| ryandrake wrote:
| I think what OP might be saying is that the attitude that
| it's OK to just yeet a rocket booster at a populated area,
| might also not yield much safety when it's applied to
| Artificial General Intelligence.
| cma wrote:
| SpaceX's flight termination system malfunctioned last year
| as well, though it was out to sea at that point.
| throwaway4aday wrote:
| That's the entire reason why they launch from the coast,
| so that if something goes wrong the debris or booster
| will fall into the ocean.
| kortilla wrote:
| Flight termination system isn't relevant when you're
| deliberately launching over land. The FTS doesn't
| disintegrate the thing
| FrustratedMonky wrote:
| Exactly. The Chinese wont be worried about 'alignment' to
| prevent bias against minorities. That will be a feature.
|
| Success is all that matters.
| thaumasiotes wrote:
| Yi Deng Wai Ren ,Er Deng Guan
|
| San Deng Shao Min ,Si Deng Yi
|
| The Chinese have copied many beliefs from the West that
| you might not have expected, including the belief that
| minorities should enjoy many more legal privileges than
| the majority do.
| Dalewyn wrote:
| China makes Saudi Arabia look like a paragon of human
| rights.
| cycrutchfield wrote:
| Let's ask the Uyghurs about those legal privileges.
| thaumasiotes wrote:
| The Uyghurs are a particularly interesting case. Like
| several Chinese minority groups, they are entitled to
| extra points on the Gao Kao .
|
| Unlike other minority groups, it appears to be relatively
| common for universities to discount their score by that
| amount.
| cycrutchfield wrote:
| Extra points on some stupid exam are supposed to make up
| for genocide/extrajudicial internment?
| hn_go_brrrrr wrote:
| I imagine you're correct if we're talking about the elite
| enjoying more legal privileges than us mere commoners.
| Both counties do have have that in common.
| diggan wrote:
| > It's this exact "succeed, at any cost" mentality that cements
| my belief.
|
| I think that's a ideology thing that goes across borders, as
| it's a problem on both sides of the pacific.
| Loughla wrote:
| In the context of this video, you're just wrong.
|
| Other countries seem to be very careful with their reentry
| plans.
| thorum wrote:
| The analogy falls apart with AI, though.
|
| - American AI "safety" practices have little or nothing in
| common with best practices in other fields of engineering,
| to the extent they can be said to exist at all (most AI
| safety work focuses on making sure the AI doesn't say
| anything that might offend someone).
|
| - When a rocket blows up, people die but we learn from the
| mistake. When an AI seriously "threatens humanity",
| humanity dies and we very possibly don't get a second
| chance.
| diggan wrote:
| I don't feel like parent was talking "in the context of
| this video" as they mentioned AI, so I figured we left that
| context behind in this comment-tree. Seemingly, I was
| wrong.
| dang wrote:
| " _Eschew flamebait. Avoid generic tangents._ "
|
| https://news.ycombinator.com/newsguidelines.html
| petermcneeley wrote:
| Is this video real? That booster seems to be falling very slowly.
| plasticchris wrote:
| It's an illusion, the larger an object is the slower it seems
| to be moving. It's pretty strong if you see a wide body jet or
| old bomber fly by at low altitude.
| macintux wrote:
| As a kid I saw an airliner landing nearby, and I was
| absolutely certain it had come to a near-stop mid-air. I
| assumed all of these years that was due to my youth and the
| fact that I was in a moving car; I didn't realize this was a
| known illusion.
| jahnu wrote:
| When I see a wide body jet fly over my home approaching a
| landing about 15km away it just looks like it's impossible
| how it just hangs there apparently little faster than an
| airship. Of course it's actually going 300km/h!
| petermcneeley wrote:
| Is there a higher quality video where we could estimate its
| velocity? It seems very slow.
|
| Edit: There is more video here. https://spacenews.com/china-
| launches-new-beidou-satellites-r...
| throwbadubadu wrote:
| Max terminal velocity of a skydiver is only 200 km/h.. if
| this booster is empty this is even maybe slower. Plus real
| slowness there is also the optical illusion of a very large
| object in some distance.
|
| So just curious, how fast would you think it should be, and
| how fast do you think it is in the video?
| petermcneeley wrote:
| It makes more sense when you see the wreckage. The entire
| booster looks like it is made of very thin metal. It is
| falling on its side just before impact so it has maximum
| drag at that stage. I would guess it is going 100km/h or
| less.
| izzydata wrote:
| Isn't the point of the booster to use up the entirety of its fuel
| to propel the main rocket? Is it normal for there to be enough
| fuel left in it to cause such an explosion?
| jackmott wrote:
| There is often some margin, and it doesn't take much. Many
| early failed falcon 9 landings were very explodey
| orbital-decay wrote:
| Yes, there's always residual fuel and oxidizer in the piping,
| it's always accounted for. For the first stage of a rocket of
| this size, it should be around a couple dozen kg, give or take.
| And hypergolic components ignite on contact.
| perihelions wrote:
| You can't pump a fuel tank entirely empty. (You could try to
| displace it with an inert filler gas--compressed helium, for
| example--but then you're replacing fuel mass with filler-gas
| mass, and that brings its own set of tradeoffs).
|
| (I understand it's a particularly deep and difficult
| engineering problem to solve this in space: in zero-gravity,
| liquid fuels turn into bubbles floating around in nearly-empty
| fuel tanks--all sorts of phenomena going on).
| CobrastanJorji wrote:
| By no means am I an engineer, but the first thing that comes
| to mind to me is those little toothpaste keys, and I wonder
| if you could perhaps just reduce the size of the canister as
| it empties. I sort of imagine a board with a spring on the
| top end of the canister that is held compressed under
| pressure but pushes towards the other end as the fuel is used
| up. Perhaps the pressure is so great when full that this is
| very difficult?
| positr0n wrote:
| If that were possible with the fuels rockets use (liquid
| hydrogen, liquid oxygen, liquid methane, etc.) it is still
| probably way cheaper on every axis to just make the tank 3%
| bigger and ignore the waste.
|
| Common axes they care about in rocket design are weight,
| cost in money, reliability/complexity, and lately
| reusability.
| mohaine wrote:
| These are not cryogenic so something is probably possible
| but this would add extra weight/mass.
|
| You do not want extra weight on your rocket. Every bit of
| non-fuel weight you add means you have to add extra fuel,
| and the extra fuel to carry the extra fuel along with any
| extra tank needed for the extra fuel. It gets bad fast.
|
| It just isn't worth it when you can just add that weight as
| fuel that normally doesn't get used. Ideally would dump in
| the ocean (which you cleared) so it didn't matter (much).
| krisoft wrote:
| They do that for smaller engines. Absolutely. They call it
| a bladder tank. Here is an article about it:
| https://www.space-propulsion.com/spacecraft-
| propulsion/hydra...
|
| > I sort of imagine a board with a spring on the top end of
| the canister
|
| You are better off doing it with gas pressure instead of a
| spring, but yeah absolutely. Very good thinking.
| krisoft wrote:
| > in zero-gravity, liquid fuels turn into bubbles floating
| around in nearly-empty fuel tanks
|
| Perihelions says it absolutely right. (Fitting nick name :))
|
| There is a beautifull footage of the phenomenon from spacex:
| https://youtu.be/mVAGoWJuDKk?si=AkjH5hAm-dHC0V87
|
| From 34s onwards it shows an internal view of the liquid
| oxygen tank. Just to better understand the picture the camera
| is inside the cylindrical tank. The viewpoint is facing
| backwards, so the camera is at the bulkhead closer to the tip
| of the rocket and it is looking "down" towards the engines.
| The blue "magical portal" is the surface of the liquid oxygen
| draining away rapidly by the rocket engines. And then
| suddenly there is main engine cutoff and the rocket is no
| longer pushed forward by the engines. That is when you see
| that the "magical portal" sloshes to the side and then breaks
| up into many floating bubbles. They float because the whole
| rocket, including the liquid oxygen is in free fall.
|
| Why is this a hard problem? It is absolutely not a problem...
| unless you want to re-ignite the engine. (Which you might
| want to do to conduct further maneuvers) If you do that and
| don't do anything special to shepherd the fuel to the pumps
| of the rocket engine they might not suck in a propellant
| bubble. If they don't your engine fails to reignite. If the
| engine ignited, but then the pumps suck in a gas bubble they
| will break apart. So you absolutely have to coax the fuel to
| the intake before you try to reignite.
|
| How do you do that? There are multiple strategies. At smaller
| scales you can try to have a flexible bladder. But at large
| rockets your best bet is to accelerate the rocket forward so
| all the propellant sloshes to the back and then you can
| ignite. Once the engine(s) are ignited you don't have to
| worry about it anymore (that much) because the acceleration
| will keep the propellants bunched up at the aft bulkhead.
|
| But if you need the engines to be ignited to accelerate, and
| you need to accelerate to ignite them then you have a
| circular dependency. How do you in theory solve this? You
| have some other mean of temporary propulsion. Either a cold
| gas truster, or a monopropellant rocket with a flexible
| blader, or a solid propellant engine. It doesn't have to be
| powerfull, and it doesn't have to push you for long. Just
| enough to collect the propellant while the main engines are
| reignited. These auxilary motors are frequently called ullage
| rockets.[1]
|
| Now of course how long is long enough, and how much push you
| need is the black magic with the whole thing.
|
| (And of course this has nothing to do with the pictured
| rockets. I don't think those are reignitable.)
|
| 1: https://en.m.wikipedia.org/wiki/Ullage_motor
| avar wrote:
| A theoretical alternative to ullage motors is to impart a
| spin on the vehicle. Then the fuel would pool at either
| end, or along the tank walls, depending on the type of
| spin.
|
| There's some diagrams and discussion here:
| https://exrocketman.blogspot.com/2021/08/propellant-
| ullage-p...
| noduerme wrote:
| Silly question, maybe, but what is filling the "empty"
| volume of that cylinder as the oxygen bubbles float around?
| Clearly it can't be oxygen or nitrogen gas, so is it just
| vacuum? In a total vacuum, wouldn't the liquid oxygen
| atomize? (And wouldn't pulling a vacuum in the tank on the
| way up make it a lot harder to pump the liquid out of it in
| the atmosphere?)
| numpad0 wrote:
| You also don't want the booster to run out of gas while still
| attached, as anything in a rocket could easily end in a
| fireball
| emsign wrote:
| That's normal for China, they don't care about the trajectory of
| their boosters and deorbited satellites.
| edge17 wrote:
| Another angle. Looks like it landed on someone's property
| https://x.com/AJ_FI/status/1739686569676566911?s=20
| cma wrote:
| https://nitter.net/AJ_FI/status/1739686569676566911?s=20
| ethbr1 wrote:
| That looks like a different booster, given that the OP isn't
| venting as it comes down and explodes.
|
| Maybe this is common?
| gs17 wrote:
| It is common AFAIK. The most used launch sites (there's one
| on Hainan where rockets only go over the ocean, but it's the
| least used) are pretty far inland and they don't seem to mind
| if boosters land on the people there or if the villages get
| toxic fuel sprayed on them.
| resolutebat wrote:
| China has four major launch sites. Wenchang, the one on
| Hainan, is used for human spaceflight. Larger cargo rockets
| use Jiuquan in the middle of the Gobi Desert. It's the
| other two, Taiyuan and Xichang (this one), that are
| relatively close to rural villages, although both are still
| very remote by Chinese standards.
| bowmessage wrote:
| Don't you mean the PRC's property?
| wolverine876 wrote:
| A better link: https://spacenews.com/china-launches-new-beidou-
| satellites-r...
| seanmcdirmid wrote:
| These have fallen out of the sky before killing people on the
| ground:
|
| https://en.wikipedia.org/wiki/Long_March_3B
|
| They launched it in Sichuan in a fairly populated region.
| Supposedly, only 6 people died, but there are rumors that many
| more were killed.
| FrustratedMonky wrote:
| Moloch is winning
| wizzwizz4 wrote:
| There are only, like, two dozen launch-capable space agencies
| in the world (ref: https://en.wikipedia.org/w/index.php?title=L
| ist_of_governmen...). This isn't a Moloch problem.
| perihelions wrote:
| That sus red smoke is nitrogen tetroxide [0], and the other fuel
| would be one of the hydrazine derivatives (I believe UDMH [1]
| here, given that the Twitter thread says this was a Long March
| 3B). It's exactly as poisonous as it looks.
|
| [0] https://en.wikipedia.org/wiki/Dinitrogen_tetroxide
|
| [1]
| https://en.wikipedia.org/wiki/Unsymmetrical_dimethylhydrazin...
|
| edit: Oh yeah, those of you who are concerned about the toxic
| fumes from gas stoves (popular HN topic), this is exactly* that
| thing--except the stoves' are measured in micrograms and what
| you're watching in rocket disaster videos is multiple tonnes. One
| of these lands on your house, and you will _not_ need to worry
| about long-term cancer risks ever again.
|
| *(To be accurate, NO2 = N2O4 interconvert in dynamic equilibrium)
| KMag wrote:
| > *(To be accurate, NO2 = N2O4 interconvert in dynamic
| equilibrium)
|
| ... and isn't N02 red while N204 is clear? So, to be pedantic,
| the red they're seeing is N02?
| perihelions wrote:
| Exactly!
| cmrdporcupine wrote:
| Nicely uphill from the rice paddy this video was taken in, too.
| I'm sure that rice will be extra delicious as the rains wash
| the residues into the field.
|
| WP about N-Nitrosodimethylamine, which apparently
| dimethylhydrazine is a precursor to _" Contamination of
| drinking water with NDMA is of particular concern due to the
| minute concentrations at which it is harmful, the difficulty in
| detecting it at these concentrations, and to the difficulty in
| removing it from drinking water. It does not readily
| biodegrade, adsorb, or volatilize. As such, it cannot be
| removed by activated carbon and travels easily through soils.
| "_
| ordu wrote:
| _> what you 're watching in rocket disaster videos is multiple
| tonnes_
|
| But this one hardly had multiple tonnes,hadn't it? It was a
| spent side booster, so the most of the stuff had been burned
| before the separation, I think.
| onetimeuse92304 wrote:
| When you send a rocket to space, you want a margin for error.
| Usually this is couple percent for the first stage.
|
| Given that the total weight of fuel at launch in this thing
| is couple hundred tonnes then yes, the margin for error can
| be multiple tonnes, but we will not know because the exact
| value will depend on the particulars of this launch.
| itishappy wrote:
| If you're interested in this sort of stuff, I cannot recommend
| the book Ignition enough. It's got the information density of a
| textbook, but it's filled with hilarious commentary and
| fascinating anecdotes.
|
| https://library.sciencemadness.org/library/books/ignition.pd...
| cylinder714 wrote:
| Ignition! is back in print, happily.
| fransje26 wrote:
| "I love the smell of hydrazine in the morning."
| kens wrote:
| NASA has a vintage 1966 video "Toxic Propellant Hazards in
| Rocketry" that provides an interesting discussion of the dangers
| of nitrogen tetroxide and hydrazine propellants. It includes
| people mixing them together in the desert, along with a
| dramatization of how to deal with a nitrogen tetroxide leak.
|
| https://www.youtube.com/watch?v=ND2TeNfcmKA
| csours wrote:
| Amazing how villagers these days have cell phones that can take
| high quality video. My villagers are walking around with wicker
| baskets and wooden hammers.
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(page generated 2023-12-28 23:01 UTC)