> One former employee, who spoke on condition of anonymity due to their nondisparagement and nondisclosure contracts, acknowledged the gulf between theory and reality. They described SpinLaunch’s prototype centrifuge as a relatively unsophisticated machine that “any average engineering team could put together.” The employee said that scaling up to a functional suborbital launcher is going to be “very challenging” with SpinLaunch’s resources. The employee also cited the inexperience of some of the leaders. “The foresight to predict many of the issues that are going to happen was definitely lacking,” they said.
Maybe they figured out some advanced materials science we don't know about, but that seems unlikely from this article.
> Over the next few years, the team ran hundreds of high-speed tests. Most of them were to study and improve the system, but some were to mollify skeptical investors and potential customers who didn’t believe a payload could withstand the extreme forces. The team sent solar cells, radio systems, telescope lenses, batteries, GPS modules, and control computers whirling at high speeds; they all survived with little to no damage. In one test, Yaney attached an iPhone to the tether and spun it up until it experienced forces 10,000 times stronger than gravity. Afterward, he used the phone to FaceTime a colleague. Each test was a step, however small, toward space.
Something tells me that an iPhone definitely cannot withstand forces of 10,000g.
Like someone below said, this either has mil implications or a way to separate investors from their money.
Juan Alonso, an aerospace engineer at Stanford who did due diligence for one of SpinLaunch’s investors, understood my reservations. “It's an exotic technology, and the first time you hear about it you think there's no way that could possibly work,” he says. But after checking out the math himself, Alonso gave the investment firm the green light.
So a Stanford guy is putting reputation on stake. Interesting.
10000g's will make the effective mass of them 400kg.
Could an iPhone survive 400kg sitting on top of it?
It's definitely within the realm of possibility...
> We’ve been putting together a team of engineers who, for the most part, are too young to say SpinLaunch couldn't work.
Fuel is a minor portion of launch cost. SpinLaunch is saving fuel but throwing away rockets; it's going to be hard to compete with someone who throws away more fuel but saves the rockets.
These kind of forces are pretty insane compared to even the high G boost you get on a normal rocket launch. I wonder if that is going to put a crimp on their potential client list.
2. Use it continually to arbitrage energy prices. Buy low sell high.
3. At launch time divert the rotational energy to the centrifuge. (I'd like to see that clutch.)
4. Profit
Obligatory link, "Moon is a Harsh Mistress", by Heinlein: https://archive.org/details/TheMoonIsAHarshMistress_201701
That's gotta be one hell of a fairing.
Your comment is very on point. If they slowly even out the atmosphere, they loose the speed. So they'll need to coordinate the door opening at exactly the right moment. And if it doesn't the whole instillation goes boom.
I feel like it would be better just to use the money to buy more rocket fuel at this point. This is so much alike to "game changing ideas" like the hyperloop, solar roadways, and other "disruptive" tech that make a cool headline, but break down the second you think about the real world logistics and cost.
I hope they prove me wrong if they can get it to work though, cheaper space flights could help the world in so many ways.
Maybe it's a minor thing, but it's a big tell to me. He says: "My team and I", in the possessive, and to me that always betrays something in founders that I don't like.
The best founders I know usually focus more on the team than on themselves. It's subtle, but I think it's meaningful.
The projectile is going to go boom when it hits the thick lower atmosphere going many times the speed of sound when it exits the vacuum chamber regardless.
Although, I guess for something about to go 5000 mph through the atmosphere, a little extra air probably isn't a big deal.
Maybe the hatch cares though.
I think this is actually a big deal.
The Mach angle is going to be extremely tight, so the profile of a normal spacecraft design would look like a flat plate at that speed. Normally, the craft is designed with a body shape roughly matching the Mach angle, but that would make it look like a long needle and you’d never be able to spin that up.
So instead, you can use a hypersonic projectile to open up the pressure envelope in front of the payload. This would be a big chunk of tungsten in a tear-drop shape. In this case, the shape is not for laminar aerodynamics; it’s for keeping mass in front for positive ballistic coefficient, and maintaining the same shape as it erodes. This is required because it has to stay ahead of the payload. Of course you can also make a train of these increasing in width and spaced to match the pressure cone.
The calculation for how much energy this takes is the sum of: 1. Mass to orbit. 2. The atmospheric pressure times the atmospheric height times the area of the Mach cone. 3. Heat losses. We can compute minimum values for the first two to get an idea of how much energy is required. I’m not sure about heat losses, but I think it’s roughly half the energy budget.
Overall I’d naively expect this to end up being more efficient than carrying fuel to orbit.
Unless they are releasing liquid, releasing two projectiles a half cycle apart (which still isn't optimal) or something similar, I can't see how the counterweight doesn't just turn the structure into dust instantly. If it isn't perfectly the vibrations will just eat the thing.
If you could guide the counterweight, maybe you could use the thing for either forging [0] or bonding of metals [1]
"a counterbalance spinning opposite the rocket gets released at the same time, preventing the tether from becoming unbalanced and vibrating into oblivion"
Air resistance is a function of the velocity squared and the air density. Air density is a non-linear function as well- it gets very thick near the ground.
To put all your energy into maximizing your speed while you're at ground level (the spin launcher) you're wasting huge amounts of energy just pushing air out of the way. At hypersonic speeds, you'
Rockets, by contrast, go their slowest at ground level and continually accelerate as they get higher. In SpaceX launches, they actually have a period where they throttle back as they go through "Max-Q", the highest aerodynamic pressure point, as it's more efficient to be slower until you're past this point.
I guess using electrical energy, which is a much cheaper source than chemicals like rocket fuel, makes the payoff worthwhile? I dunno, I'm skeptical.
Oh also you can only launch this somewhere that no one around will mind an insane sonic boom at ground level.
Perhaps instead of directly spinning the object up to speed and "letting go", you could build up all of the energy into a heavy rotating mass which then imparts it into the spacecraft over a slightly longer timeframe via some simple mechanical clutch and cable arrangement. You would still have very strong g-forces, but you could control the impulse curve over time to spread out the forces better.
Steel cables, flywheels and other members aren't going to care about such forces as much as the delicate electronics on board a spacecraft. Let these parts do the heavy lifting and then transmit the energy into the spacecraft in a methodical manner. You need to decouple the extreme nature of this sort of energy storage system from the spacecraft until it is go time.
Sounds like this solves the easy part (getting to high altitude), but makes the hard part (getting to orbital velocity) even harder.
This will have lateral forces, then sudden relaxation of those forces (shock unloading) and then sudden vertical forces when it hits dense atmosphere.
Or do they somehow counter the spinning of the tether, so that the rocket's orientation remains static? If there's another bearing at the attachment point, I don't see how just the outer bearing would withstand the friction at 10000g.
If they do pull it off, the logical next step would be to use SpaceX-style reusable rockets as well, in which case you'd save both fuel and rocket costs.
Making the rocket reusable would be the next step, but that's a nontrivial task itself, since it's effectively the upper stage which is the hardest part of reusability. Maybe it's easier for such a small rocket, I don't know. But even then they're just shaving a little fuel off a very low launch cost, in exchange for a 200 lb max payload that has to be hardened to 10,000 gees. The launch cadence would be an advantage today but Starship is supposed to launch three times per day, if the customers are there for it.
I believe the sweating skin idea has been dropped. See this one hour video for a detailed breakdown of the current state of the design:
Their goal is to allow the rocket to ignite at 200k ft. Thats only a bit lower than the altitude SpaceX ignites its second stage, which is not reusable
It seems like this launch system will be more expensive per kg, and have far greater loads on the payload than Falcon 9.
I hope it works out, and they find ways to make it commercially viable, but Falcon 9 really has set the bar for success quite high.
Totally agree that the SpinLaunch system does not seem sufficient to get a payload to space though, let alone if it also needs to bring propellant for circularizing their orbits.
Solid state electronics and fuel. With respect to the former, nothing that requires stable orientation. I don't know of a propulsion system that can survive those forces.
Water. Fuel. Clothes.
Maybe this is what can kick start the 3D printing in space revolution.
Maybe it can also launch radioactive waste into space? One bucket at a time. Then a space towtruck can be launched to hurl it into the sun.
But it’ll likely just part a naive investor from their money.
The total amount of radioactive waste on the earth is about the size of a swimming pool (or was that the total amount of gold? I forgot, either way in terms of quantity it's not that much), burying it deep and forgetting about it for the next 100.000 years is the way to go I think.
If they could just launch at 45 degrees to get to orbit the rockets would do that too, but no they don't. They go straight up at first because the drag is such a huge penalty to the performance.
If they actually build this thing, the most efficient way to launch is to launch it almost straight up at 90 degrees so they lose the least energy. However the hardest part is going to be immediately after exiting this thing where they hit the atmosphere going mach 6-7 and instantly turn into a glowing ball of plasma, which is what happens if you try to move that fast at sea level.
Drag forces increase with the square of the velocity and linearly with fluid density. The instant it leaves the cannon it will feel like it's hitting a brick wall.
This thing is going to tear itself apart as soon as it leaves the centrifuge.
Centrifugal projectile weapons scale up poorly and have issues even at BB gun scale. Envisioning what happens with a 200lb projectile; leave aside the laughable velocities they're talking, and I want to be well distanced from these people when they power shit up.
I think this is a device for separating investors from money.
If I understand correctly, this would hold for angular acceleration too, since they'd just release at some point. Can someone correct me if I'm wrong?
I've seen very spectacular footage of these rounds tearing a hole in the atmosphere ... so maybe our shared intuition isn't reliable...
or maybe once you get a cross section bigger than a playing card, things become.... interesting at these speeds at sea level;)
P.S. It also appears 'grok' has fallen out of favor over the years. It's too bad, I always liked how subtle it was - the distinction between knowing WHAT something does and WHY it does it(eg fully understanding it)
There is just too much that could go wrong here.
I would be positively shocked if this thing works. I'd have to rethink a lot of things I hold an opinion on.
I have heard them say repeatedly that the physics work. Physics are 'easier' than manufacturing/building something...lab scale/bench scale are exponentially easier than full scale...full scale is exponentially easier than building something consistently. Ask Tesla.
I have yet to hear them talk about how they are manufacturing parts for the full size centrifuge. When I hear them mention forging or the heavy press program or similar I'll take them slightly more seriously. I'm trying to conceptualize what the arm would look like and the force it would have to withstand and honestly can't.
Right now, they have been stuck for years on 'trust us this doesn't violate the laws of physics' which is not comforting when I only ever hear that from cooks.
When I first heard of it, I was thinking, this must be a bad April Fool’s joke, or an incredibly great idea. Turns out, it was the former.
https://en.wikipedia.org/wiki/Launch_loop
I said the physics works. The engineering is a totally different question.
So if the engineering is questionable or unrealistic, how is it less fanciful?
Take a 200 pound payload, add some rocket to it, let's say 10x the weight to be generous, then spin it in a circle 200 feet in diameter. You're looking at 18 thousand tons of force spinning it at 5000mph. So you're spinning 4 navy destroyers worth of force in a circle, which means you need a latch mechanism that can not only hold that much force, but release it at the exact moment to exit the biggest vacuum chamber ever created through a door that just opened at the right time, generating a mach 6+ shock wave at about 0 meters distance from the door and somehow not destroying it in the process. I don't know that it is impossible, but it is highly improbable. They'd probably have a burst disk rather than a door, because that would let you use the capsule as a bullet to penetrate the exit.
In the article they mention the payload experiencing 10000g, so they must be planning on a circle greater than 200 feet in diameter. I can't find numbers on existing satellites, but I remember reading that rockets typically top out at 6g acceleration and figure on a 10x momentary acceleration due to vibration. To tolerate 10000g the payload being launched will need to be built like a tank, rather than the relatively light current designs. To ease that requirement you could submerge the payload in liquid, but that would decrease your usable payload accordingly.
It would be impressive if they could actually pull it off. I think it would be useful for limited applications. I have watched science fiction shows where mass accelerators could basically nuke planets without radioactive fallout. Maybe this would be something similar.
And just for a sense of scale, escape velocity from earth's surface--assuming no atmosphere at all--is 25,000 miles per hour. The projectile is going to tear itself apart in atmosphere at those speeds.
IMHO the centrifuge part is the easiest of their challenges.
0.000000000001 > 0
This seems wrong in both places. There are probably enough gold rings manufactured per year to fill a swimming pool. In pictures: Fort Knox itself seems to have at least a swimming pool of gold [1] and Thailand a swimming pool of waste.[2]
[1] https://external-preview.redd.it/rgD0FO1pELgkuXZzWC2NQk0vJZU... [2] https://upload.wikimedia.org/wikipedia/commons/9/93/TINT_Rad...
A normal swimming pool is about 25m x 12.5m x 2m which is 625m^3.
https://en.wikipedia.org/wiki/United_States_Bullion_Deposito...
This page indicates Sellafield has 2000m^3 of high level nuclear waste.
Is there a problem with burying it in a subducting plate boundary, so it is eventually pulled back into the earth's mantle? There's already fission going on down there.
Surely you’d just need enough to end up in a decaying orbit? Then it’ll eventually reach the sun
Zero to Mach 5 or 6 just seems like an instantaneous disassembly manuever, both for the craft and the centrifuge itself. Did they find a way to suppress a sonic boom at the exit point?
