Let's all go reread "The Moon is a Harsh Mistress."
this post was submitted on 02 Feb 2025
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Lotta coulds, ifs and mights in this breathless koolaid-drinker's puff piece (actually he's probably just a shill). Lotta rendered images and animations. Lotta lack of anything tangible. Lotta totally irrelevant misdirection in the bottom half of the puff piece.
This isn't a news piece. Nothing new has been done with this idea. It's basically an ad (for vaporware). The headline is technically misleading, as no such thing has been done yet.
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Has it ever launched anything into orbital altitudes yet? So it's like AI, then? Let's pour money into it asap!
You can (theoretically) reach "space" with a single impulse from earth's surface, but you cannot achieve earth orbit that way. To make orbit, you need a circularization burn at apogee to raise your perigee above the atmosphere. Otherwise, its ballistic trajectory will cause your spacecraft to re-enter the atmosphere.
Yeah, this is just a first stage replacement. You still need a rocket to get most of the way into orbit.
The first stage counts for the bulk of the fuel and total mass, so this would still be a big deal.
Yeah definitely. The way the rocket equation works out, the second stage gives most of the Delta V, but the first stage needs to be much bigger because it needs to lift itself and the second stage.
In theory, with an impulse hard enough to reach the moons orbital altitude, you could get a slingshot maneuver that leaves your object in a highly elliptical orbit around earth without burning fuel, but it would eventually be unstable from the moons gravitational pull changing it.
Engineers who spent their whole childhood watching Loony Toons: βMy time has come!β
I haven't see any kind of news or update from them in over a year
Yeah looks like they ran out of money.
Actually, I stand corrected. It looks like they raised $11.5 million a few months ago and are working on a ruggedized little satellite that would survive their centrifuge.
Also, "founder and CEO Jonathan Yaney left the company" ?
https://payloadspace.com/spinlaunch-raises-11-5m-to-hurl-more-spacecraft-into-the-sky/
I remember watching debunking video of this years ago. If I remember right, the problem was how to stop a projectile (a rocket in this case) from spining once it's released. I need to find that video ...
I did watch that and there are problems but the debunking video itself was really bad and acted like there were problems that had already been addressed in the video it was a direct response too. It still seems like a crazy idea but they have had test launches and there didn't seem to be a spinning issue.
OK, but couldn't the item have some small thrusters with a control system to cancel out any tumbling/spinning once it's launched? That would require some fuel, but a lot less than required for a traditional launch...
And wouldn't fins like on an arrow take care of stabilizing spin around the major(?) axis?
Pls don't flame me, I'm not a physicist or rocket-scientist :)
Did it tumble during it's test launch?
https://m.facebook.com/story.php?story_fbid=2069436850145993
50 States, 50 Protests, 1day
Feb 5 @ your downtown.
Pass the word!
Why not use a magnetic launch and put rockets on a rail gun? You could put it on an inclination and accelerate that sucker over multiple kilometers if you wanted to in order to build up the velocity you need. The g-forces would be concentrated in one direction Wouldn't that reduce the number of problems?
You'd have to make it in a hyper tube or it'll just vaporize, which is damn near impossible to keep depressurized even without the rail gun. Or you could put it in a giant sabot, but those are expensive and their own technical challenge. Not to mention, good luck adjusting it for a different orbit... The power requirements are going to be insane too, which means a ton of huge capacitors
This way, they depressurize a nice pancake shape, spin it up over the course of hours, and let the projectile pierce out through a brake away cap. If they can make it work, it's a better design in every way
The spin launch thing is easier to do than what you're proposing.
A straight rail gun would require INCREDIBLY LARGE amounts of energy to be outputted in minimal time.
The spin launch contraption inputs energy into the spinning hand or whatever slowly over time. The spinning hand stores this energy as rotational energy. This way, while the payload has to go through high g forces for a longer time, you don't need fancy apparatus to input energy.
When it's time to launch, the hand suddenly lets go of the payload, instantaneously converting all that energy to kinetic energy.
The challenge here ofc is to make the hand VERY strong. That's why it's literally a block of carbon fiber.
I really want this thing to work, but uk... They haven't demonstrated any significant breakthroughs yet. I just hope they don't run out of funding before showcasing something substantial.
Why would it cost more energy to accelerate the same load on a linear path than on a circular path? Where does the additional energy requirement come from?
And why do you assume the time has to be minimal? You can make the rail quite long, kilometers long in fact.
Spin Launch releases at 2.1km/s or 2100m/s . Say you want to reach that with 9.8 m/sΒ² (earth's gravity) that's 2100/9.8 ~= 214 s so about 3.5 minutes . The distance traveled is s = 0.5 * a * t * t --> s = 0.5 * 9.8 m/sΒ² * 214s * 214s = 224,400m = 224 km.
That however is at a relatively lower acceleration. Rail guns have barrel lengths of a few meters e.g Japan 6 m and release their projectiles at 2km/s or 2000m/s. If my math isn't wrong, that's 333,333 m/sΒ². The projectile of 320 g is nowhere near the 10,000kg that Spin Launch aims to release, but let's see how much energy that requires. I'm out of time to calculate that, so if you want to, please do.
According to the transcript of this video interviewing Spinlaunch, claims to require 100MWh with a spinup time of 2 hours.
But we don't want to accelerate 10 tonnes to 2.1km/s in 6 meters. That's insane. The rocket is probably longer than the entire rail. 10km maybe even 50km would be more realistic.
Why would it cost more energy to accelerate the same load on a linear path than on a circular path?
I didn't say that. I said that you would need to input a lot of energy in much less time.
Now, how would you do that in a linear acceleration system? Well, you would need an unimaginably large capacitor bank if you're going the electrical route. Or, you could use chemical fuels, but then stuff would get way more complicated as you would have to deal with plumbing (if you're using fluids), reliable detonation, etc.
In this case, you're just storing all that energy in the carbon fiber hand, which basically is a flywheel.
And why do you assume the time has to be minimal? You can make the rail quite long, kilometers long in fact.
All acceleration that a payload would receive is when it's in the gun. So let's say, the first 100m give it a 1000g acceleration. But, when it enters the next 200m, it's already going very fast. Therefore, it would spend very less time in the next 100m section. Thus, the payload would get WAAAAAY less acceleration.
This means, that you get diminishing returns in terms of initial velocity as your gun increases in length.
Another issue is that you would be able to launch stuff in one direction only. What if I want to launch in polar orbit? I would need to build another km long gun in that direction. Compare this to spin launch, where you could quite easily point the launch apparatus in whatever direction you want to launch in.
Also, the spinning thing is in a vacuum. The rail thing has loss due to drag.
Wouldn't the changing magnetic fields damage whichever electronics are housed in the payload?
I don't believe so. The electromagnetic energy is being used for acceleration, no other type of energy. The inside could easily made into a Farady Cage to block some of the electro-magnetic fields.
Can we use this to throw people we don't like?
It would squish them first.
That's fine we didn't like them to begin with.
Spin your enemies at high speeds in a vacuum until they're dead then launch their corpses into space
I think I saw this in one of the bond films. Only his watch saved him iirc.
Throwing them is gonna kill them anyway, squishing is fine
Launcher may handle 10,000 g's, but satellites tend to be kind of fragile
Youβd be surprised how well modern cubesats are already designed implicitly with high-G components. There was a video about them testing an βoff-the-shelfβ sat from a professor and it held up with only some minor modifications.
How many oceangates is that? Can we send CEOs in it?
euthanasiacoaster without the extra steps
Satellites have to go through shock and vibe testing based on the vehicle bringing them up, satellites using spinlaunch will need to be built around it.
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I want it to work because it would be so fuckin cool. Yeet my ashes into orbit pls.
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not possible. This could work for orbiting probes but only if you send up a little fuel with it as well. The orbital mechanics work out so that the probe will fall to the height of the catapult which is in the atmosphere.
What prevents them from doing exactly that?
Lots of (all?) satellites have propulsion systems to make orbit adjustments anyway. Is it that complicated to bolster them a bit for that purpose?
Well I just meant the restriction in the title where it said no rocket fuel. Its not possible if you have no rocket fuel. But they probably will use rocket fuel if they get the faucility to have a big enough diameter to get mostly to orbit.
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