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...
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.
I want tailor made drugs that convince my brain all this exists while in the real world we live docile, simple lives to extend the viability of human habitation on Earth.
The material resources do not exist on Earth to switch to EV cars. The idea we’re going to live on Mars is hallucination.
Transfer of consciousness to other substrates is far more interesting than literally living out pop culture from the last half of the 1900s.
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!
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.
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).
> 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.
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.
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.
> 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).
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.
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.
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.
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?
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.
1. The right star system (including organics and potentially habitable planets)
2. Reproductive molecules (e.g. RNA)
3. Simple (prokaryotic) single-cell life
4. Complex (eukaryotic) single-cell life
5. Sexual reproduction
6. Multi-cell life
7. Tool-using animals with intelligence
8. A civilization advancing toward the potential for a colonization explosion (where we are now)
9. Colonization explosion
We have made it through 7 of the 9 steps and are currently in number 8. I would call that the end stages of the Great Filter.
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.
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
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.
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.
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.
> 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.
Wonder if it could be precision enough for non-military applications? eg possibly faster for deep geothermal drilling than using the existing surface based borehole drilling approach.
For military applications though, it'd wonder if such a rod (or small sequence of them) could be effective when striking geological fault lines. eg the San Andreas Fault line
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.
"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.
> 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...
> 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.
Now, this is a mature reaction to calling out handing nukes to toddlers. Well at least you took it constructive, by turning the discussion towards the material science of toddlers and societies they form. That, right here, is why we cant have nice, but dangerous things.
And remember, you got time to build up momentum, a ion drive accelerating in a spiral with swingbys, with one final push, can get you pretty high on the C if you dont want it right now.
And i was not referencing the expanse. I was referencing todays solar driven ion engines. Boring tech. Marathon tech. But given enough time it can move a mountain up a notch, without drag.
> And remember, you got time to build up momentum, a ion drive accelerating in a spiral with swingbys, with one final push, can get you pretty high on the C if you dont want it right now.
No. You're not even getting close to your ion drives exhaust velocity, which is <100km/s.
So you are not accelerating ANY kind of asteroid for more than ~10km/s, because the closer you want to get to your exhaust velocity, the harder your scheme gets slapped down by the rocket equation-- "unlimited energy over time" does not even enter the equation.
So what you are left with is the option of finding an asteroid that you can get into a collision orbit with earth as cheaply as possible.
Even to just break even with the weakest nuclear weapons, you need at least 500 metric tons at 20km/s. You'll probably need something around 300m/s of delta-v (that would be a mars/earth transfer).
And this needs to happen quickly, because there is no stealth in space and everything you do can be observed and reverted (leaving aside the fact that any weapon system with a deployment delay measured in years is absurdly impractical).
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.
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.
> 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.
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.
Ah, lovely to see Murderbot mentioned, I've just been re-reading it.
I think it's fine to take scifi tech with a grain of salt; most authors skip the absolute technical details so we just have to assume that things work in some way we don't currently understand. Someone did the calculation for the Epstein and it doesn't look great: http://toughsf.blogspot.com/2019/10/the-expanses-epstein-dri... but only based on the vague technical details provided in the books.
The Jean Le Flambeur trilogy is one of my favourites, it does a LOT of quantum hand-waving but the price is worth it for all of the amazing things in that universe. "This sounds so fucking cool" > "That wouldn't work irl" for good sci-fi imo. As long as they don't mess with thoroughly understood concepts and rely on "things we don't know yet".
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?
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.
> 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.
> 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.
Reading the news, my gut feeling is that US and China are preparing the ground for war between each other, though it makes no sense from an economical point of view, so perhaps I'm reading it wrong.
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.
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.
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
What’s this thing to do with the future except it looks nice? We have people these days focusing too much on the presentation rather than actual development.
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?
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.
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.
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.
.. 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.
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.
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.
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.
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.
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.
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).
> 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...
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.
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.
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
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.
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.
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?
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?
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.
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.
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:
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
The dumping of excess fuel would have been done after satellite deployment, which as per this page: https://www.nasaspaceflight.com/2022/07/starlink-4-25/ is at 230 km (140 miles). This is way, way above the atmosphere and there is no way it would have produced any effects at ground level.
Whatever happened at your place, it was nothing to do with this launch.
"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
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"
> 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.
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.
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.
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.
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.
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.
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.
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.
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.
