r/physicsgifs • u/29NeiboltSt • 21d ago
The insane physics behind a mass accelerator technology designed to move payloads into space by company called 'SpinLaunch'
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u/bluecalx2 21d ago
That's a very cool idea, but it seems like if things are off by the slightest fraction of a second, the entire structure is going to explode.
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u/cedenof10 21d ago
smallest imbalance and it goes to shit, lol
that said, I was more thinking about an accidental release where it doesn’t have enough energy to reach orbit, only enough to be a very effective kinetic projectile
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u/CynicalWoof9 21d ago
a very effective kinetic projectile
You mean a missile.... right?
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u/deelowe 21d ago
My understanding is that they've already abandoned the project. I don't think space launches were ever really their goal. My guess is they were aiming for defense contracts and that fell through
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u/DublinItUp 20d ago
I have a family friend that previously worked for space x and now works for another company that launches satellites. I asked him about this company before and he told me that unless you're launching something the size of a phone it's kind of useless.
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u/Leptonshavenocolor 20d ago
When they first came out I thought this is the most elaborate ponzi scheme or something. I'm excited for companies to attempt challenging things, but their entire premise is based on having everything under vacuum. I work with vacuum equipment, no fucking way you can seal something that large in a vacuum state. And they didn't even have answer for questions like what are you planning for when the projectile somehow transitions from the impossible vacuum chamber to hitting atmosphere without completely decentrigrating.
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u/intisun 20d ago
I love when tech companies and moguls treat the most essential details as mere afterthoughts. Like how Musk keeps talking of colonizing Mars but never addresses the question of radiation, food, and the absence of a magnetosphere.
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u/GarglingScrotum 20d ago
I think this is true of a lot of things we already use. Rockets, jet engines, etc. The tolerances on these machines are very low
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u/ThingAdditional2720 19d ago
Just like rockets, no? Smallest thing is off the whole structure goes boom.
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u/worotan 21d ago
Considering they’re measuring pressure and reporting it as ‘nominal’ rather than an exact figure, I’m not inspired with confidence in their precision.
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u/Adept-Panic-7742 21d ago
It's a promo video not spec document
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u/worotan 21d ago
It’s a public statement of how serious they are. I seem to have upset the kids.
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u/Adept-Panic-7742 21d ago
No. The specs would be relative and since they haven't built it, this is just a video demonstration.
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u/Adept-Panic-7742 21d ago
Nice edit on the end there. I'm not a kid I'm an aerospace mechanical engineer.
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u/PM_me_ur_bag_of_weed 21d ago
Absolutely not. Orbital velocity for low earth is like 5 miles per second. And that's without the wind resistance so you'll need to go even faster at launch if you can even protect that thing from tearing itself apart from the G forces. The rpm that thing would be spinning at is ludicrous, and once the payload is deployed, you now have an unbalanced helicopter rotor spinning at mach fuck you.
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u/apworker37 21d ago
They have a counterweight that releases simultaneously. After that they just have to brake/coast down.
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u/McChes 21d ago
Where does this counterweight go when it is released? Is it launched down into the Earth?
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u/Slight_Concert6565 21d ago
It would have to, if you want to let go of it at the same time you launch the payload.
Better get a really good deceleration tunnel, maybe using Lenz law you can magnetize the counterweight and drop it into a metallic tunnel, or the opposite.
It would still be a massive pain in the neck, mostly because the accuracy would suck ass. I don't think you could get this to aim anywhere closer than 0.1 degree off, and that would still fuck up your trajectory completely.
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u/ElectricYV 19d ago
At that point, it already seems like an inordinate amount of effort and funding for just one projectile
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u/BoosherCacow 21d ago
That would have been handled by onboard propulsion. Never would have worked though, or at least to me it seemed like moonshine.
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u/Slight_Concert6565 20d ago
Onboard propulsion can correct the trajectory, but if it's already off there is no correction to be done.
In other words, the onboard propulsion can make the payload turn slightly, but if it's not where it should then turning won't do much. It's like steering between lanes after missing an exit on the freeway.
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u/BoosherCacow 20d ago
Except you don't drive around the world on a freeway passing the same exit again and again. You can absolutely change your orbital plane. You wait until you get to the point in the wrong plane where it intersects the correct one (ascending or descending nodes they're called) and do a burn from there until your plane is the correct one. With enough fuel you could change from an equatorial to a polar orbit.
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u/Slight_Concert6565 20d ago
My comparison was indeed too simplified, but my point is that the thruster shown here doesn't look like it could correct for long enough.
Hence my comparison with the freeway: a rocket drops the payload with an error near the end of the travel, while the spinlaunch has the payload start with an error that will be amplified along the way with only a little bit of available thrust to correct the trajectory.
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20d ago edited 20d ago
[deleted]
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u/Slight_Concert6565 20d ago
Even with circularization, a small error at the launch needs a lot of power to be corrected. I think the thruster shown in this simulation would be way too small to correct that if the payload has already gotten most of the energy it is supposed to carry into orbit.
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u/Boonpflug 18d ago
I saw a more convincing approach that starts in space with a tether and two mirrors. The sun’s radiation causes it to spin with no friction until the tether breaks and it flings some probes out of the solar system. If you don’t care for aiming and just for speed this approach is nice without friction. A launch from earth fulfils none of those requirements of course.
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u/IttsssTonyTiiiimme 20d ago
Not a physicist by any means, so be gentle, but isn’t it the case if this thing is off, it could just hurl an object into a city?
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u/Juggs_gotcha 21d ago
This was a vaperware project to siphon defense contracts from gullible boobs. It never even came close to working.
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u/Jest_Dont-Panic_42 21d ago
I’ve never like this idea, would rather like to see a magrail launch system. Possibly starting out in an underground ‘hyper-loop’ type of tunnel. Still would take some major engineering to make it worthwhile.
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u/Slight_Concert6565 21d ago edited 20d ago
I too would prefer a good ol' railgun to send shit into orbit, much more accurate and less likely to "oopsie daisies, timing was off by 10 ms and we threw the payload into the nearest town."
Only issue with the railgun is the magnetic field could damage the payload, it would just need extra shielding but that shielding would then have to be discarded. Maybe there could be a way to reuse the shielding somehow? Like by having a way to have it lend mostly intact in a somewhat controlled area?
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u/iloveu10000 19d ago
Your comment made me think about this video at 4:30
https://youtu.be/-a1QP9rsm6g?si=piWxlyMzDJHVpk0x
The sled the shell would ride on would just be the entire length and once it hits the open air resistance it would fall away.
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u/Slight_Concert6565 19d ago
Yeah kind of, but the sled would be quite a lot bigger here so it would have a lot more energy, I dunno how easy it would be to catch it.
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u/CatchAllGuy 20d ago
But I think rail gun would impart unbearable g's on the projectile.. in comparison this one can build up the speed rather slowly. Nonetheless it is going nowhere I think
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u/Slight_Concert6565 20d ago
G is acceleration, make a long straight railgun and you can have only a few Gs.
Spinning it up would impart lots of Gs through centrifugal force since you have to spin it very fast.
Centrifugal force will always be worse because it's equivalent to accelerating the payload from 0 to full spin in half a rotation, on both axis, every rotation.
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u/CatchAllGuy 20d ago
My bad, how could I make such a comment. Btw thanks for correction
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u/Slight_Concert6565 20d ago
You're browsing reddit bro, of course you might not be at your peak awareness of the day.
I too said some shit I only decided not to delete for educational purpose because the person correcting me explained it well. And boy do I cringe when looking back at some L takes.
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u/FrickinLazerBeams 20d ago
This was obviously never viable. It's the kind of thing you cook up to extract some venture capital from an idiot banker.
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u/Leptonshavenocolor 20d ago
I think you mean impossible physics. Unless they have changed what they're doing, the notion of pulling a vacuum on their setup is wildly naive.
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u/7LeagueBoots 21d ago
Haven’t heard about them in a while. Are they still in business, or did they go belly up?
They had issues with pulling the necessary vacuum, timing, weight balance, and stability in flight.
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u/YolognaiSwagetti 20d ago
that "insane physics" is literally just basic mechanics that you learn in high school physics class. I mean the device looks incredibly sophisticated but the principle behind it is very simple, it's the exact same thing as rotating around and throwing a ball.
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u/bugo 21d ago
How do you stop object rotation? It's not visible in n the ball but rockets have a pointy end.
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u/RichardDucard 21d ago
The rocket is being held with the center arm till release, while the ball isn't.
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u/bugo 21d ago
Yes but what stops it from spinning fuck-rpm after it's released. Conservation of momentum and shit.
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u/biemba 21d ago
Air resistance?
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u/aalapshah12297 21d ago
On one hand they have to launch it at such a high velocity that it can counter air resistance & gravity all the way from earth's surface to orbit.
On the other hand the angular velocity needs to be low enough for air resistance to stop its rotation quite early along its flight path to give the required stability to the payload.
Both can't be simultaneously true as the angular velocity would be proportional to the linear velocity.
You'd need some kind of mechanism to rotate the payload backwards as it revolves forward in the launcher, but that would probably create many more problems then it solves.
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u/Chazykins 21d ago
It’s not just going to keep spinning, to move in a circle like that a constant force must keep changing the direction of the rocket, as soon as it releases the rocket travels in a straight line.
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u/bugo 21d ago
Yes it will move in a straight line but it will keep spinning around its center of mass.
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u/bender-b_rodriguez 18d ago
Yes the projectile itself would have its own spin after being released, can see it clearly if you watch the hammer throw event or picture it clearly if one takes a second to think about it instead of immediately slamming the downvote button like a moron. I don't know how SpinLaunch plans to deal with that, maybe they release the front first then the back and let the projectile aerodynamics take care of the rest.
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u/darthvall 21d ago
Try to find a video of how David's sling shot works. I originally thought it's just Kid's sling shot that worked like arrow (draw the string and release), but actually the ancient sling shot uses similar principle as this mass accelerator (swing the sling in a circle and release).
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u/jhudiddy08 20d ago
Imagine the unbalanced loading on the axis the moment the payload is released. That’s the failure I would worry about.
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u/jawshoeaw 18d ago
There’s a second load simultaneously released into a braking tunnel or something
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u/ardvarkmadman 20d ago
wouldn't there need to be a counterweight also released in the opposite direction?
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u/jedihooker 20d ago
So… what happens to the counterweight after the projectile is released? Seems like the whole system goes to shit after launch.
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u/Raaka-Kake 20d ago
What happens after loosing a significant and now imbalanced portion of the mass of the still fast moving spinner?
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u/commandercondariono 19d ago
I feel like anyone with even a preliminary knowledge of physics and engineering would have bad first impressions of this idea.
The spinning thing has to be incredibly well balanced with and without payload. The payload has to sustain side-on accelerations in addition to the end-on ones.
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u/kaiju505 18d ago
On a small moon with no atmosphere, maybe. Having worked with vacuum systems, the spin launch would be an expensive nightmare. It’s like tech bros got bored thinking of shittier ways to make trains and moved on to shitty ways to blow stuff up trying to get to orbit.
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u/Crackheadthethird 18d ago
This is one of those super impractical ideas that has no potential. I still don't know how it got the funding it did.
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u/intimate_existence 18d ago
The contents of that projectile will definitely be mush by the time it makes it to space.
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u/syizm 17d ago
The insanest thing about this is actually thinking its a viable business model.
I applaud any attempt at trying to get away from fossil fuel/derivative means of propulsion but... speaking as an engineer here... this idea seems absolutely wild and almost stupid. So much so that it makes me think maybe its just TOO brilliant for my brain.
I wonder if a magnetic rail could generate a comprobable range of g-forces with a smaller carbon footprint.
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u/MrStumpson 17d ago
Delete this post. Company has been dead in the water and a failure for years. Nothing but hype.
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u/Andreas1120 21d ago
Seems these guys had a set back and their next project does not use spin launch. Promised a new facility in the nebolous future.