[HN Gopher] Giant SpaceX Spiral Appears Amid the Aurora Lights i...
___________________________________________________________________
Giant SpaceX Spiral Appears Amid the Aurora Lights in Alaska's
Night Sky
Author : dxs
Score : 254 points
Date : 2023-04-18 13:18 UTC (9 hours ago)
(HTM) web link (petapixel.com)
(TXT) w3m dump (petapixel.com)
| andsens wrote:
| > Those were the best hours of blissful bewilderment.
|
| What a fantastic alliteration to describe his state of mind :-)
| rolph wrote:
| no joke intended, that rocket flew over my cabin and knocked
| stuff off the shelves.
|
| one earthquake did that about three years ago, had it not been
| for the subsequent hardening , i would have lost my preserves to
| a rocket.
| mlindner wrote:
| I'm not sure what you're claiming. Rockets cannot cause
| shockwaves on the ground by flying over you in space. You
| experienced something else and misattributed it.
| [deleted]
| rolph wrote:
| you are quite wrong about that, and im sure it wasnt "in
| space".
|
| i live in a place between two major installations, and see
| uncommon things often. [such as X-45 variants
| https://en.wikipedia.org/wiki/Boeing_X-45]
|
| this happened a little before 2:00 hours saturday morning,
| and was the loudest thing ive ever heard and felt in my life,
| and was definately not an earthquake, or a hurricane, i saw
| the spiral.
| mlindner wrote:
| It was in space though. You're misattributing it.
| rolph wrote:
| so what altitude was it maintaining when it went over
| alaska?
| dabluecaboose wrote:
| I'm sorry, but you're definitely misattributing this. The
| rocket in question was launched from Vandenburg SFB in
| California. It was not close enough to you by the time it
| reached Alaska to have knocked anything off a shelf.
| rolph wrote:
| so it didnt fly over central matsu valley, denali range
| and delta junction?
|
| https://www.theguardian.com/us-news/2023/apr/18/northern-
| lig...
|
| perhaps you could enlighten me with a trajectory during
| launch, and during stage recovery. im not the only one
| that saw the spiral, and i had nieghbours on the next
| ridge that were disturbed by it as well, they thought the
| noise was my fuel exploding.
| dabluecaboose wrote:
| No, it definitely did fly over you. I apologize that I
| was unclear in my earlier comment. I meant to say "It was
| not close enough to you _by the time it was over Alaska_
| " since it was a polar launch (Northward)
|
| I'm not telling you that you didn't see the spiral, I'm
| telling you that there's no physical way that it could
| have knocked anything off your shelf from the upper
| atmosphere.
| rolph wrote:
| so 50-60 miles is recognized as the edge of space, is
| that too far for a shockwave to travel?
|
| im looking at the idea this was re-entry shock from an
| jettisoned booster stage, either that or there was
| someonelse , using the spaceX as cover for thier own
| launch, but i havnt heard about anything from Kodiak.
| dabluecaboose wrote:
| It's difficult to say what precise altitude it was at,
| but the spiral formation is from the final booster stage
| jettisoning fuel so that it doesn't explode on re-entry.
| That means, in very broad terms, the spacecraft and the
| booster were likely in the low earth orbit regime, and
| likely just under orbital velocity for the spacecraft.
|
| Given that the spiral had a northward azimuth from Delta
| Junction (as per the article) the draining happened after
| it had already passed overhead, and it was likely very
| far away when it actually re-entered. At an inclination
| in line with Vandenburg, it likely landed in the Pacific.
|
| I am an astrodynamicist but my work in launch dynamics is
| a bit rusty, so bear with me if my off-the-cuff estimates
| are off.
| rolph wrote:
| that seems to describe the path, the [sound] intensity
| was in sync with the path of the spiral.
| beefok wrote:
| https://earthquake.alaska.edu/event/0234u0lcjp
|
| https://earthquake.alaska.edu/event/0234u01ap5
|
| Would it have been around this time? I'd be interested to
| know if their seismographs can be used to detect non-
| earthquake recordings.
|
| When I was little I lived less than an hour from Cape
| Canaveral and damn, when those shuttle missions launched,
| you'd feel it in your bones. I'm not sure how it would feel
| if it were just in the air crossing my path though.
| rolph wrote:
| 2nd link would be the closest but not, the right time.
| there was definately acoustic energy, in the air, this
| wasnt ground tremor, it was distinctly different, and the
| volume followed the appearance, zenith, and dissapearance
| of the spiral.
|
| it was not a snowquake either, and it wasnt from Clear,
| or Elmo.
| cs702 wrote:
| Cool visual effect, apparently created by emission of excess fuel
| by SpaceX rockets with Starlink payloads. Great photo.
|
| Make sure to watch the video too, taken by an all-sky camera run
| by the University of Alaska. The video shows the spiral as it
| starts forming at ~1:30. The spiral expands to cover much of the
| sky, and then dissipates -- all in just a few seconds.
| yread wrote:
| I find the northern lights captured by the camera much more
| interesting than the rocket spiral
| tqkxzugoaupvwqr wrote:
| In 6-7 minutes real time (see timestamp bottom right). The
| video is sped up.
| cs702 wrote:
| Sorry, yes. That's what I meant. Thanks! :-)
| dmix wrote:
| Another example
|
| https://youtube.com/shorts/9SZY_QEozWw?feature=share
| aardvarkr wrote:
| Thanks for including the time stamp. That's a pretty amazing
| sight to witness
| Uptrenda wrote:
| We really are living in the future... and it happened so fast.
| It's like on one of those empire games where you research the
| space age and get access to crazy tech. We are now capable of so
| many advanced feats. It feels like only a few years ago were
| primitive compared to today. What will tomorrow have? Personal
| space ships? Underwater houses? Houses for sale on other planets?
| Service robots? It's mind blowing...
| unixgoddess wrote:
| yeah, a future that chokes on pollution, constantly on the
| brink of annihilation by ever more powerful weapons, with
| freedom ever more vanishing under growing mass control
| systems... all so you can have some silly gadgets that you'll
| get bored with in a day, always chasing for the next shining
| toy
| monkaiju wrote:
| God if this is the future, I dont want it...
|
| Despite so much technology we still have so much precarity and
| poverty with new massive destabilizations happening every day.
| What a nightmare
| JohnFen wrote:
| It doesn't feel that way at all to me, honestly. Aside from
| (maybe -- it's legitimately hard to tell) advances in AI, and
| cell phones, there hasn't been any earth-shaking advance that
| makes times in my past seem primitive to me.
| monkaiju wrote:
| I hate to say it but yeah, like smartphones are maybe the
| only thing I feel I've really experienced in my life that
| made a big impact. And even those came with way more
| downsides than I would've hoped.
| [deleted]
| dylan604 wrote:
| The 1950s called and wants it's meme back. Seriously, though,
| the 50s promised flying cars, personal jet packs, moon bases,
| etc. They were so convinced cars would fly, they all came with
| wings on them =) Houses underwater was a thing they thought
| were right around the corner as well. It really reads like you
| just picked up a Scientific American magazine issue from your
| doctor's office lobby that's from the 50s.
| WalterBright wrote:
| > They were so convinced cars would fly, they all came with
| wings on them
|
| I think that styling trend was due to making them look like
| jet aircraft. The taillights mimicked jet exhaust pipes
| closely. Even the front grille was often fashioned to look
| like a turbine intake.
|
| Jet engines were some of the coolest, most visible, and most
| advanced tech in the 50s.
| phpisthebest wrote:
| Anyone remember or watch 90's TV Show Seaquest DSV. its
| timeline had us living in underwater stations by now.
| Gordonjcp wrote:
| Octonauts is the Seaquest DSV reboot we didn't know we
| needed.
| jhpankow wrote:
| Unfortunately Sealab 2021 was more accurate in predicting
| the future.
| Paul-Craft wrote:
| I'd say _Biodome_ and _Idiocracy_ were far, far more
| accurate.
| JohnFen wrote:
| And Idiocracy is a hopeful movie -- it shows how an
| enlightened leader (Herbert Camacho) can actually help
| society move out of a collapse (that feels more and more
| likely to happen in real life).
| LargoLasskhyfv wrote:
| Not really. Because at the end some annoyed pimp called
| _Upgrayedd_ tunnels there through time. Presumably to
| pursue an upgrade for his revenue stream.
|
| Fuck yeah!
| dylan604 wrote:
| Yeah, but if you're Not Sure, then it's really hard to
| convince other people as well though.
| hef19898 wrote:
| Idiocracy got the timeline wrong so, Star Trek and co
| assumed we are much faster, Idiocracy assumed we are much
| slower.
| Izkata wrote:
| Star Trek's DS9 episodes featuring Sanctuary Districts
| were set in 2024, and Star Trek's WWIII started around
| 2026. We're kinda on track.
| Loughla wrote:
| I was joking with friends, that it appeared that people
| saw shows like Star Trek and Star Wars, and thought -
| hey, we can do that.
|
| The problem is that politicians and governments saw shows
| like Idiocracy and Space Balls, and thought - hey, we can
| do _that_.
| WalterBright wrote:
| Star Trek convinced me that keyboards spit out sparks and
| smoke and throw you across the room if you type in
| illogic.
| Loughla wrote:
| If only.
| codebje wrote:
| Star Wars is pretty dystopian in every era shown in the
| movies. Even at the height of the Galactic Republic large
| areas of the outer rim have people living in poverty and
| outright slavery. Coruscant appears nice, but a little
| below the surface criminal gangs are running the place
| with most of the planet's population never even seeing
| sunlight.
|
| Plus the powerful elite tapped into the discontent that
| they'd created in order to further their own power, then
| crushed the useful idiots who rebelled against the
| oppression and doubled down with more oppression.
| matthewmcg wrote:
| Boy that takes me back. I liked to think that Roy Scheider
| was playing the same character he played in _Jaws_.
| [deleted]
| oceanplexian wrote:
| > The 1950s called and wants it's meme back. Seriously,
| though, the 50s promised flying cars, personal jet packs,
| moon bases, etc.
|
| Maybe they were right but a little off on the timeline. For
| example there was a lot of crazy tech that people thought
| would take off in the 90s and flopped, but are now a reality
| (Online shopping, smartphones, electric vehicles).
| ben_w wrote:
| > Seriously, though, the 50s promised flying cars, personal
| jet packs,
|
| You can buy those, they're just expensive to buy, to run, to
| insure, and to learn how to operate.
|
| But you _can_ buy them.
| jjulius wrote:
| They're also, more often than not, far more limited in
| scope and capabilities than their imaginative 50's
| counterparts.
| dylan604 wrote:
| i want my flying car that collapses and folds up into a
| briefcase like in the Jetsons. parking should be that
| easy
| WalterBright wrote:
| Watch the Jetsons. You'd be surprised at how many of
| their futuristic gadgets we have today.
| dylan604 wrote:
| Yeah, and, so? We don't have the briefcase car and that's
| what I want. Don't come with your whataboutisms and try
| to make me accept less. Your games are transparent!
| garryindiana wrote:
| [dead]
| snovv_crash wrote:
| The future has arrived, it just isn't evenly distributed
| yet. - William Gibson
| mholm wrote:
| And soon, it'll be smeared out into a broad global layer
| of what a Pakistani brickmaker would consider to be
| prosperity - Neal Stephenson
| Aperocky wrote:
| Futurologist back then must have placed almost no importance
| on the cost of energy.
|
| Might be due to the fact that man made energy was quite a new
| thing and it's getting cheaper quite fast and seemingly
| boundless.
|
| Like Moores law. It ends eventually.
| HPsquared wrote:
| There are still a couple of orders of magnitude within
| reach, if we can commercialize molten salt reactors. After
| that, solar power in space (using asteroid or lunar mining)
| for gargantuan scale.
| AYBABTME wrote:
| The cost of energy would have been less of a problem
| without nuclear scare.
| bryanlarsen wrote:
| The price of energy dropped continuously and exponentially
| from 1873-1973, and ~1973 is the start of the "great
| stagnation".
|
| The price of energy recently resumed its exponential cost
| reduction, but only for those who have access to solar
| energy. Hopefully those cost reductions result in price
| reductions for the rest of us soon.
| kitsunesoba wrote:
| Sometimes I wish I could've been around to experience that
| kind of forward-looking optimism. I got a small taste of it
| in the mid-late 90s, but from the looks of it, 90s futurism
| was rather tame in comparison.
| KineticLensman wrote:
| I'm just old enough to remember the massive optimism
| associated with the Apollo program (I was a space-obsessed
| nerd kid). The mid to late 70s though were depressing by
| comparison, without the rapid cadence of the moonshots.
| Broken_Hippo wrote:
| .... and in the next decade, I saw the Challenger blow up
| in an elementary school gymnasium.
| lucideer wrote:
| Particularly applicable given we also had spaceflight in the
| 50s...
| franky47 wrote:
| If you're a billionaire, maybe.
|
| For everyone else, the current climate trajectory doesn't bode
| well.
| tediousdemise wrote:
| [flagged]
| IAmGraydon wrote:
| If we don't kill ourselves in the next 100 years, I think the
| future will be pretty amazing. We're passing through the end
| stages of the Great Filter currently. This is the part where
| we're sufficiently advanced to create technologies that can
| destroy the planet (like nuclear weapons) but not advanced
| enough to shed our ancient animal instincts of war, conquest
| and power. I personally do not think we will make it through
| unless there is a greater power (civilization) looking out for
| us. I guess we'll find out soon enough.
| tediousdemise wrote:
| [flagged]
| wongarsu wrote:
| Within in the next ~100 years we will advance to a state
| where nuclear weapons taking out one planet won't kill our
| civilization outright anymore, and within the next 200-500
| years we might reach a point where even war across an entire
| solar system won't be enough.
|
| There's the risk that we will develop stronger weapons to
| match our increasing resilience, but on the other hand in the
| last 100 years we've made good progress on either outlawing
| many weapons of mass destruction or at least making their
| development much harder, so there's hope.
| lm28469 wrote:
| > we will ... we will ... we will
|
| Not much more substantiated than what people believe will
| be the return of Christ, it's all sci-fi
|
| Not much fundamentally changed in the last 100 years, even
| a nuclear reactor is just a fancy steam engine. We're
| closer to horse carriages than a solar system wide
| civilization
| qikInNdOutReply wrote:
| The problem is that planetary civilization is inherantly
| fragile to those living up outside the gravity well. Every
| depressed belter asteroid-trucker with a balistics
| computer, can throw a garbage can at earth or mars at speed
| and end planetary civilization.
| CyberDildonics wrote:
| I think you're confusing reality with science fiction.
| philwelch wrote:
| Rods from god are roughly as powerful as nukes, which is
| bad but a single nuke wouldn't end planetary
| civilization. If the belters were able to throw things at
| relativistic speeds you'd have a problem, but there's
| also no stealth in space so it's feasible to monitor
| space traffic around a large planet and deflect anything
| incoming, be it a projectile launched from longer range
| or an untrusted, uninspected, shady-looking belter ship.
| stametseater wrote:
| I think rods from gods is oversold. The classic version
| of this is a "telephone pole of tungsten", or something
| along the lines of a 6 meter long cylinder, 0.3 meters
| across, which works out to 0.42 cubic meters of tungsten,
| which would be just over 8000 kilograms. If you do the
| math, rods coming in at orbit speeds are barely worth
| talking about; the actual rods from god USAF proposal had
| these tungsten telephone poles starting in orbit and
| impacting the ground at merely 3 km/s, equivalent to 11
| tons of TNT.
|
| Faster then: the kinetic energy of such a mass moving at
| 12 km/s, faster than escape velocity, would be 'only' 137
| tons of TNT, approximately 1/15th of the 2020 Beirut
| explosion. Even if you throw the rods into the ground at
| a blistering 50 km/s, that only gives you the equivalent
| kinetic energy of 2.4 kilotons of TNT, or 1/6th of the
| Little Boy nuclear bomb.
|
| Then there are the terminal effects; such a tungsten rod
| is basically an oversized armor piercing dart like tanks
| shoot at each other. It will drive itself straight into
| the ground and most of the rod's kinetic energy will be
| spent pulverizing bedrock and itself. Such a weapon would
| be great for taking out bunkers, but I think very
| wasteful for any other purpose.
| m4rtink wrote:
| Anything small enough will just burn up in the atmosphere
| and big stuff will be easy to detect, even at the boost
| stage as the initial orbit change might take weeks or
| months possibly.
|
| Orbitals at predictable orbits and surfaceinstallations
| on airless bodies might be more in danger though. There
| even a well targeted fast crowbar might do quite some
| damage.
| justinclift wrote:
| The "rod from space" just need to deflect the orbit of an
| already existing large asteroid doesn't it?
|
| Which would hopefully be detected in time to "solve" the
| problem, but still... ;)
| AlotOfReading wrote:
| "just" is doing a lot of work there. It's a pretty
| serious engineering effort to move rocks around the solar
| system and unless you have unlimited-energy future tech,
| you're probably stuck with the current paradigm of
| nudging things slightly to take advantage of convoluted
| gravity assists and small time windows to move things
| about. It'd be a very slow and predictable weapon that we
| already watch for.
| myrmidon wrote:
| This is complete BULLSHIT.
|
| Your understanding of orbital dynamics is completely
| off-- "asteroids" are not a viable antiplanetary weapon
| and NEVER will be.
|
| Changing the asteroid orbit costs you pretty much just as
| much energy as your impact is worth-- so you could just
| as well have launched the engine that is supposed to move
| your asteroid, and exploded in on-target.
|
| The whole subplot in _The Expanse_ only works because:
|
| 1) The drive technology violates conservation of energy
| and powers the impact (duh)
|
| 2) The "stealth paint" which glosses over physical
| impossibilities; You can't really hide over the whole
| spectrum (how is your "paint" supposed to deal with
| wavelengths that approach the object size?).
|
| And both of the above are pure fantasy.
|
| Better go play Kerbal space. And I seriously mean that--
| it is going to give you a MUCH better intuitive
| understanding of orbital dynamics than school or
| university could ever provide.
| wpasc wrote:
| how dare you besmirch the Epstein drive
| myrmidon wrote:
| Don't get me wrong I obviously liked the books enough to
| read them, but I still firmly believe that it is vitally
| important for sci-fi authors to just shut up about
| scientific details that our current understanding is not
| equipped to provide.
|
| There are books that are WAYY farther from our current
| techlevel, like _Murderbot Diaries_ or _Ancillary
| Justice_ , which handle this much better. I just don't
| see how adding pseudoscience improves ANYTHING-- better
| to just gloss over it.
| stametseater wrote:
| It's very far from practical technology, but in principle
| you can use pieces of the asteroid as reaction mass to
| 'cheat' the rocket equation. You could also modify the
| asteroid's albedo or use solar sails to modify the
| trajectory of the asteroid.
|
| _Very_ far from practical. Such a plot would probably
| take centuries at least to carry out with reasonably
| conceived technology.
| marcosdumay wrote:
| > Changing the asteroid orbit costs you pretty much just
| as much energy as your impact is worth
|
| It's about momentum, not energy. Near Earth, you can get
| energy from the Sun quite easily, or fuel a nuclear
| reactor with the asteroid.
|
| Momentum is gathered by throwing reaction mass around.
| And reaction mass is what asteroids are made of.
|
| > The drive technology violates conservation of energy
|
| Do they explain it somewhere? I always got the impression
| it was a kicking-ass nuclear fusion engine.
| myrmidon wrote:
| > It's about momentum, not energy. Near Earth, you can
| get energy from the Sun quite easily, or fuel a nuclear
| reactor with the asteroid.
|
| I'm not sure if you're being deliberately obtuse.
| Momentum does absolutely nothing for you by itself-- it
| does not even affect penetration depth of your asteroid.
|
| The only thing momentum does is that it scales with speed
| (hint: like kinetic energy).
|
| If you have enough fuel for a nuclear reactor to throw
| pieces of asteroid into space, then MAAAYYYYYBE just
| launch nuke at the planet?!
|
| Because that is:
|
| 1) Easier to build
|
| 2) Simpler
|
| 3) Harder to detect
|
| 4) Harder to defend against
|
| edit: Sorry for the tone. This whole topic just really
| infuriates me because I absolutely can not understand how
| anyone with even elementary physics education could ever
| defend this concept as viable...
| marcosdumay wrote:
| > The only thing momentum does is that it scales with
| speed
|
| And mass...
|
| If you have a fixed amount of energy, the amount of
| destruction you can create on your target is a complex
| function of how much delta-v you need. But the maximum is
| never on the extreme of "just emit all the energy there
| at once". It can always improve by adding some mass.
|
| On those other comparisons, you probably have a point,
| assuming the people tech looks like the things we can
| imagine at realistic sci-fi.
| plasticchris wrote:
| If you do play kerbal you know that getting a big
| circular orbit to become a very eccentric one (if you
| don't care about reentry speed which is a feature here)
| is pretty cheap. Now just make that eccentric orbit
| intersect the target's orbital path and boom.
| myrmidon wrote:
| > If you do play kerbal you know that getting a big
| circular orbit to become a very eccentric one (if you
| don't care about reentry speed which is a feature here)
| is pretty cheap
|
| No its not?!
|
| Simply getting a flyby from one planetary orbit to
| another is _exactly_ the kind of expensive that I 'm
| talking about, and thats basically what you get on
| impact.
| plasticchris wrote:
| But the asteroid does not start in planetary orbit.
| sam_goody wrote:
| Iran is getting closer to nuclear weapons, and they sure
| seem to be dead set on using them.
|
| (OT: I do not understand the U.S. policy in this, but
| _surely_ they are doing everything in their power to
| prevent that, since this will affect, like, everything.
| _Right_?!)
|
| And, the tension between the U.S. / NATO vs. Russia / China
| / Iran / (Brazil ?) has lessened, but it certainly it isn't
| gone. How optimistic are you?
| wongarsu wrote:
| We went from 4-5 countries getting nuclear weapons in the
| first 15 years, and an era of about 60 nuclear tests each
| year in the 30 years after that, to the current era where
| it's about one country every 10-20 years gaining nuclear
| weapons and basically no tests happening. I'd say that's
| a massive improvement.
|
| We've also mostly stopped with firebombing, and have
| seriously dialed back the chemical and biological weapons
| that were much more popular in the WWI/WWII era.
| sam_goody wrote:
| > one country every 10-20 years gaining nuclear weapons
| and basically no tests happening
|
| This past week had a test in both N. Korea and Iran, so I
| don't think that is accurate.
|
| > I'd say that's a massive improvement.
|
| Oh, yes sure it's an improvement. But if we only have two
| countries intent on starting a nuclear war, thats already
| enough to hose the whole planet. And I am far from
| confident that we can safely say we aren't there.
| [deleted]
| stametseater wrote:
| > _This past week had a test in both N. Korea and Iran_
|
| Neither of these happened.
|
| North Korea tested a missile which could be used to
| deliver a nuke, they haven't tested any nukes since 2017.
| I don't know what Iran tested, but it certainly wasn't a
| nuke. The only news of a missile test from Iran this week
| that I can find is them testing an anti-tank missile,
| which obviously isn't even meant to deliver nukes.
| yowzadave wrote:
| Why do you think we're at the end stages of the Great Filter?
| Isn't it plausible that, as technology grows cheaper and more
| powerful, it will become easier for smaller and smaller
| groups to obtain world-killing abilities?
| [deleted]
| specialist wrote:
| Ya, we're in the beginning stages of The Great Filter.
| piyh wrote:
| A bunch of medium sized filters can look a lot like a
| great filter.
| aaroninsf wrote:
| I think the implicit premise in the GF theory is that it's
| "adapt or die," i.e. either our civilization/species
| develops truly robust means of preventing mis-application
| of high-leverage technologies, or, it goes extinct. Most
| likely.
|
| But I agree, it's a process, not a state machine.
| [deleted]
| croes wrote:
| We do still the same in terms of space travel, starts just got
| cheaper but we are no way nearer to colonize any planets
|
| And our newest toy is a machine mimicking human written texts.
|
| AR and VR like in books in movies are also not reach, self
| driving cars aren"t really a thing just like flying taxis.
|
| It's more self-deception than future.
|
| Climate change and it's consequences like new diseases will be
| problems we be the real yardstick of human capabilities.
| qikInNdOutReply wrote:
| Reminds me of the sords in crest of the stars.
| zzzeek wrote:
| "SpaceX rockets are designed to land back on Earth but the second
| stage of the Falcon 9 does not parachute down to the ground.
| Instead, it burns up in the atmosphere but before doing so it
| vents its unused fuel which will often take the form of a
| stunning spiral. "
|
| so...we are marveling at how awesome it looks to dump rocket fuel
| into the atmosphere? cool, cool
| shadowgovt wrote:
| Yes, much as we marvel at rocks slicing into the upper
| atmosphere, solar particle radiation being magnetically bottle-
| slammed into the poles, and dirty snowballs a hundred million
| miles away boiling in proximity to the sun.
|
| Humans marvel at all kinds of cool-looking things.
| 0xDEF wrote:
| The Falcon 9 second stage uses highly refined jet fuel and
| liquid oxygen. But it is an absolute trivial amount. The
| airline industry emits more GHG in a minutes.
|
| The reason it is visually spectacular is not because it is
| burning but because the fume is reflecting sunlight. Rockets
| that only emit water vapor have caused similar spirals.
| Symmetry wrote:
| And most competing launch providers use solid boosters whose
| emissions are way worse via damage to the ozone layer.
| NotYourLawyer wrote:
| It's kerosene and liquid oxygen. It's not like they're dumping
| hydrazine.
| kortex wrote:
| Even if it was hydrazine or UDMH, the half-life of molecules
| in the upper stratosphere is months/years, anything in the
| mesosphere isn't coming back down before photolysis breaks it
| down into NO2, CO2 and H2O. NO2 isn't great for ozone, so
| hydrazine usage in the mesosphere should be minimized, but
| not many platforms are using hydrazine still. Oxykero is
| totally fine.
| arprocter wrote:
| The article contradicts itself about what happens to the second
| stage "it burns up in the atmosphere" and "deorbit and
| eventually splash down in the Pacific"
|
| Seems like the latter is correct (if it was going to 'burn up'
| why would you need to dump fuel?) -
| https://en.wikipedia.org/wiki/Falcon_9#Recovery_of_second_st...
|
| I guess they figure it's better to let the fuel diffuse in the
| atmosphere than poison the ocean, or less weight to be
| recovered/sink
| ceejayoz wrote:
| The fuel dump is to prevent explosions before reentry that
| could damage the spacecraft it just delivered or create
| unnecessary space debris.
|
| https://sattrackcam.blogspot.com/2018/01/fuel-dump-of-
| zumas-...
|
| > Rocket stages always carry excess fuel, as you don't want
| the engine to cut out prematurely by running out of fuel. So
| it always has a sufficient fuel margin. Once its work is
| done, this excess fuel is often vented, also known as
| "depressurization".
|
| > Depressurization and fuel venting avoids the risk of the
| rocket stage blowing up, for example as a result of static
| electricity building up in the rocket stage. You do not want
| your rocket stage to blow up, as it creates an uncontrolable
| swarm of debris and includes the risk that particles are
| ejected into orbits where they do not decay quickly, adding
| to the space debris risk.
|
| As for burning up, it's a bit of both. Some material burns
| up, some larger chunks splash into the ocean. Same thing
| happened a while back when the US dropped bits of Skylab on
| Australia. https://www.abc.net.au/news/2020-05-31/nasa-
| skylab-fell-to-e...
| viraptor wrote:
| What's the expected impact of that much clean kerosene in open
| air? It's dangerous to breathe in for people in closed spaces,
| but I couldn't find any estimate of how much of the leftovers
| would be dumped.
| kortex wrote:
| Zero. That's not even in the true atmosphere at that point.
| The kerosene droplets will rapidly evaporate into free
| molecules and then diffuse around the mesosphere/thermosphere
| for months/years until radiation breaks it down into first
| lighter hydrocarbons, then carbon dioxide and water.
| gpm wrote:
| Planes also dump a ton of kerosene into the air when they
| need to land early. I'd assume orders of magnitude more than
| rockets just because there are so many more of them.
|
| They also dump it much, much, lower in the atmosphere. Where
| people and other things are more likely to breathe it.
| CommieBobDole wrote:
| As close to none as possible, really - you're diluting
| probably a ton of kerosene in five and a half quadrillion
| tons of atmosphere. Plus it's happening ~150km up, mostly
| outside the atmosphere, so it's got a long time to dilute
| before it gets to anyone.
| kortex wrote:
| I mean, we've gone from stuck squarely on this rock to being
| able to escape our gravity well in a geological blink of an
| eye, so yeah, it's quite marvelous.
| jtode wrote:
| Ahh, maybe that's why my service has been spotty lately -
| sattelites diverted to light shows.
| stronglikedan wrote:
| It looks really cool. And it's fleeting. And it looks really
| cool. I'd love to see it in person some time. And it looks
| _really_ cool. And to think it 's man made, and on a level with
| the awe of nature. I'd love to travel all that way to see the
| Aurora, _and then_ get treated to that as well. I don 't see the
| problem.
| [deleted]
| HenrikB wrote:
| In the video on
| https://vimeo.com/818040730?embedded=true&source=video_title...,
| it appears around the 1m29s for a few seconds corresponding to
| 08:46:54 - 09:57:09 UTC in real time.
| rurp wrote:
| I'm torn on this. On the one hand it's a really cool visual,
| coming from some impressive engineering. On the other hand, I am
| absolutely not looking forward to the night sky becoming filled
| with light pollution.
| agloe_dreams wrote:
| I think you might be mixing up this with the actual Starlink
| sats, which yeah, def pollution. This is from the second stage
| reentry and only happens for a few minutes in a specific area.
| Theoretically, Starship will not do this as both stages are
| reusable...buuuut I imagine they will end up trashing a few
| stages on the way to get there.
| shadowgovt wrote:
| When people complain about the effects rocketry and space
| colonization will have on astronomy, this is what I think about.
|
| Like... How many people complaining about the effects of Starlink
| satellites have ever actually _seen_ a Starlink chain drift by,
| like beads on an invisible string?
|
| It's mesmerizing.
| shpx wrote:
| You would love pouring engine oil on a puddle. I recommend
| doing it when it's windy, it's more interesting when it's being
| pushed around.
| dotancohen wrote:
| I watch satellites deliberately. There's about an hour after
| sunset, and another hour before sunrise, when most satellites
| are visible. Between those hours, the satellites are in the
| shadow of the Earth and not visible.
|
| I've observed a Starlink chain (the second full chain launched)
| after sunset, it was absolutely amazing _and inspiring_. I've
| also tried to observe a chain that I knew was overhead about
| midnight - and even as an experienced satellite watcher
| actually looking for them and knowing where they were, I could
| see nothing.
| [deleted]
| subpixel wrote:
| I saw one once and my immediate thought was that I hope such an
| aberration of my natural view of the sky doesn't become common.
| I would describe it as eery.
| shadowgovt wrote:
| Eerier than the infinite void with points of light suspended
| in it by nothing at all?
| subpixel wrote:
| Eery like the beautiful display of color that oil reflcts
| when it's suspended on water.
| pjot wrote:
| I think we're already past that point. I can hardly see stars
| now given the amount of light pollution my city puts off.
| Little dots zipping around won't change much.
| philwelch wrote:
| I think we're in an in-between stage--at some point, it'll
| be within reach for people who want an uninterrupted view
| of the night sky to catch a ride into orbit and just look
| out the window up there.
| JohnFen wrote:
| > it'll be within reach for people who want an
| uninterrupted view of the night sky to catch a ride into
| orbit
|
| The thought that would be necessary just to see the night
| sky depresses me beyond belief.
| capableweb wrote:
| The difference is that at least light pollution from the
| ground/cities you can at least get away from by going to
| remote places. The satellites you can't really do anything
| about, they'll appear no matter where you go, even in the
| middle of nowhere.
| Beldin wrote:
| Perhaps, if you were to move (as in: relocate), you might
| find that we're not completely past this point yet.
| pjot wrote:
| At least in the US, over 80% of the population lives in
| an urban area - practically speaking, we've passed the
| mark.
| buran77 wrote:
| Cars were mesmerizing at one point. The novelty wears off and
| even if the utility is still there, the drawbacks are no longer
| hidden by the glitter that for some reason catches some eyes.
|
| People who care about the night sky won't be impressed by that
| sight more than by actual beads on a string. Certainly not for
| long, especially when they realize what it means for that night
| sky.
| mlindner wrote:
| Except those beads on a string will not be a normal or
| regular sight. They're a coincidence of deployment mechanism,
| separation method, satellite design, and orbit design.
| They're temporary and as the constellation fills up, will
| become less common.
| etiam wrote:
| .. at which point they'll just be shredding visual records
| of the sky in their regular orbits as densely as the
| companies have been allowed to cram in.
| shadowgovt wrote:
| It doesn't mean anything to the night sky. The night sky
| definitely doesn't care one way or the other.
| woudsma wrote:
| I couldn't believe my eyes when I saw a Starlink chain in the
| sky from my balcony in Amsterdam. We have a lot of light
| pollution so I was amazed to see it from the city.
| rglover wrote:
| It'll be even more mesmerizing when it's sending OTA updates to
| your Neuralink chip to get you back to work.
| willidiots wrote:
| I thought the same at first too, then realized this is
| mesmerizing beautiful *pollution*. Similar to the iridescent
| sheen of an oil slick on the ocean.
| shadowgovt wrote:
| Pollution implies harm, and there's no harm here. Contrast
| light pollution which makes all sky phenomena invisible.
|
| If anything, this is adding something to the existing dance
| of the stars and planets.
| lm28469 wrote:
| > Pollution implies harm
|
| That's news
| JohnFen wrote:
| > there's no harm here
|
| Define "harm". I think astronomers would disagree with your
| assertion.
| shadowgovt wrote:
| They already account for planes and existing satellites;
| we have solutions for this, they simply need refinement
| and deployment.
|
| (... and that's before we consider that cheap launch
| infrastructure means we can also address the problem by
| launching telescopes, which would put high-quality
| imagery completely unobstructed by atmosphere in the
| hands of far more astronomers than can touch that tech
| today).
| gammarator wrote:
| Starlink affects even space telescopes in LEO:
| https://www.space.com/hubble-images-spoiled-starlink-
| satelli...
| JohnFen wrote:
| > we have solutions for this, they simply need refinement
| and deployment.
|
| As I understand it, it's not quite as simple as that when
| the number of satellites gets large.
|
| > that's before we consider that cheap launch
| infrastructure means we can also address the problem by
| launching telescopes
|
| The cost of the launch is not the largest part of the
| cost of having space telescopes.
| shadowgovt wrote:
| > As I understand it, it's not quite as simple as that
| when the number of satellites gets large.
|
| I'm not sure "simple" is the term I'd use, but given the
| satellite ephemera and timestamps, the algorithm for
| knowing where the satellite is and therefore ignoring
| that chunk of sky when the satellite passes through is
| well-understood (and we can certainly mandate that every
| launching organization maintain correct and up-to-date
| ephemera).
|
| Telescopes observe a tiny, tiny sliver of the night sky.
| The density of satellites necessary to interrupt them
| continuously would be something well past the expected
| launch capacity of this century alone (and would create
| its own navigational problems were we to achieve it).
|
| > The cost of the launch is not the largest part of the
| cost of having space telescopes.
|
| Not as they've been done, because the cost of launch was
| so high that it could only be justified by putting a
| perfect-mirrored device that could see all the way back
| through spacetime to the first microseconds of the cosmos
| in orbit. Now imagine the economics when you're putting a
| hundred up at that price, not one (and you can use
| algorithms to combine signal from them to account for
| lower resolution).
|
| ... imagine having, with the right math, an aperture the
| size of the orbital diameter of the Earth itself...
| JBorrow wrote:
| For part a) that is only true for a small selection of
| observations. A huge proportion of astronomical science
| comes out of surveys that typically use large fields of
| view. Additionally, observation times can be very long,
| so even if you are looking at a small bit of sky you can
| still end up having things ruined by a satellite.
|
| For part b) you are completely incorrect in your
| assumptions here. The majority of the cost and effort of
| telescopes is really in the instrumentation (the
| 'cameras' that are strapped to the back of the
| telescope). To get the most out of an observing facility,
| we need access to these to change them, fix them, and
| improve them. This is not possible with a space-based
| mission.
| shadowgovt wrote:
| I feel like there's a whole world of information theory
| that either astronomers or (I suspect) people making
| arguments on behalf of astronomers are unaware of.
|
| Long-duration observations can't be disrupted badly by a
| quick satellite jaunt across the sky. That's just a noise
| blip. Less than 0.00001% of the data collected. Isolate
| it and scrub it.
|
| Similarly, wide-field observations have a lot of data to
| work with to figure out what the field is supposed to
| look like vs. what it looks like with a satellite-pass
| event. Isolate them and scrub them.
|
| Satellites and deep stellar phenomena are different
| scales of event at different ranges and speeds. A Fourier
| transform should make them show up as obviously
| separable.
|
| (... and again, all of this is assuming you have to scrub
| this data without a-priori knowledge, when the disrupting
| event is a well-documented passover with clear ephemera.
| If it is mandated that satellite companies publish the
| ephemera, which I think is a perfectly reasonable burden
| upon them, it should be even easier to separate signal
| and noise).
|
| I do see your point regarding (b) though; space telescope
| science may require a wholly new approach relative to
| terrestrial science.
| femiagbabiaka wrote:
| It's mesmerizing now at small scale, at anything resembling the
| kind of scale I think SpaceX wants to target it'll just be
| noise, like contrails.
| darreninthenet wrote:
| My wife and I were sitting outside chatting around our fire pit
| in our back garden as do sometimes when the weathers nice and
| we saw this row of continuous white dots all evenly spaced
| passing over us and we were like "what the f????" as it was
| obviously not natural.
|
| Quick post on Facebook gave us the answer but yeah at the time
| it really was a "wow" moment
| euroderf wrote:
| I'm wondering what effect this has on isolated Amazonian and
| Papuan tribes.
| shadowgovt wrote:
| I've never really known what to make of this concern.
|
| We plan to some day colonize the moon itself. How much should
| we be concerned about how it will effect isolated Amazonian
| and Papuan tribes when the moon is lit up with a hundred
| points of light on the dark-crescent side as the phases
| shift, and one can make out the twinkle of ion drives or
| torch ships crisscrossing from lunar to Earth orbits? Enough
| to never colonize the moon?
| [deleted]
| specialist wrote:
| I'm more torqued about light pollution. Every creature should
| be able to look up at the Milky Way and wonder. (Or simply
| navigate. YMMV.)
|
| If astronomers are truly bent about satellites fouling their
| earth bound observations, they should demand SpaceX put more
| telescopes in orbit. Those would be better any way, right?
| gammarator wrote:
| Astronomers are not in the business of getting an emotional
| reaction from looking at the night sky, we're trying to learn
| facts about the universe by making quantitative measurements--a
| process that megaconstellations indisputably degrade.
| MisterTea wrote:
| Looks like they missed an opportunity to visit the Black Lodge
| and say hi to the Arm.
| samstave wrote:
| So van Gogh's Starry Night was showing how CERN and SpaceX sent
| multiple rockets back through his time?
| adzm wrote:
| Why is there so much excess fuel to begin with?
| tuatoru wrote:
| Contingency planning.
| BenoitP wrote:
| I wouldn't say there is a lot of excess fuel as a percentage of
| the mix in exhaust gases, but there is some, by design. Maybe a
| few percents.
|
| Why do we want some fuel in the exhaust? Burning an oxydizer-
| rich mix is not a good idea, especially with a reusable rocket.
| You'll have a very hot gas that is going to burn-corrode your
| engine. Metals can burn in an oxygen-rich air. Now imagine that
| mix at 3,600 K and 300 atm pressure. You'll have what is called
| in the industry an 'engine-rich' burn. You don't want that.
|
| Also, I don't know about this rocket but sometimes you want to
| cool down your nozzle and you can do that with unburnt fuel
| that you inject from the side.
|
| Running a stochiometric mix puts you also at risk of damaging
| your engine (some parts of your mix might be oxygen-rich), on
| top of combustion temperature being higher.
|
| Now, burning a fuel-rich mix make these problems go away. And
| does not decrease much your thrust: heated at very high
| temperatures, this residual fuel will expand and contribute to
| some part in the force generated.
|
| Last, a fun fact: you can detect when then rocket leaves the
| upper atmosphere with the flame color! That's when the flame
| goes from being orange (high temp residual fuel meets oxygen
| from the atmosphere and burns) to being grey (flame meets the
| atmosphere but not enough oxygen to relight it, and soot is
| grey). You can clearly see it happen around 40km altitude here:
|
| https://youtu.be/xY96v0OIcK4?t=15881
| corbulo wrote:
| Thanks for making HN awesome
| LeonM wrote:
| To add to the other (good) answers: it is also because this
| makes (re)starting the engines in zero gravity easier. Liquids
| behave very weird in 0g, trying to suck fuel from a nearly
| empty tank in 0g can be challenging. Leaving more fuel in the
| tanks makes this less of a challenge.
| Symmetry wrote:
| Physical systems aren't perfectly predictable, and so require
| feedback. You include a little more fuel than you think you
| need so that if you use more than expected, say because solar
| conditions make the atmospheric drag a bit higher, you won't
| run out with the payload just shy of the intended orbit.
|
| But during re-entry there's no reason to keep that with you and
| if by some chance your stage arrives intactish at the ground it
| might cause a fire. Hence the venting before re-entry.
| pixl97 wrote:
| In case something doesn't work as efficiently as possible.
| Since these rockets are not specialty designed for each launch
| you only save a very tiny amount of money/weight by not filling
| it all the way up.
| 0xDEF wrote:
| There isn't that much excess fuel. The reason it looks so big
| and dramatic is because of water vapor and fumes reflecting
| sunlight.
| Tuna-Fish wrote:
| That's not all that much fuel. There's always some margin in
| the tanks to make sure that the turbopump won't ingest a
| bubble, and probably a little more so that if the rocket
| underperforms slightly on ascent they won't lose the mission
| because they skimped on 50kg of fuel.
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