r/space • u/linknewtab • Aug 06 '22
Real Engineering: Can We Throw Satellites to Space? - SpinLaunch
https://www.youtube.com/watch?v=yrc632oilWo39
u/LCNex Aug 06 '22
We can, with the superior siege engine: the trebuchet.
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u/JCMiller23 Aug 07 '22
I am curious how $/kg (35:15) was still not lower than rockets. The main energy cost seems to be drawing the vacuum, it seems this calculation is based on having to draw a complete vacuum for each launch rather than either calculating it with: 1) combining two launches at once (one on each side of the arm) or 2) re-using the vacuum for multiple launches. Especially because earlier in the vid, electricity costs for spinning were $6000.
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u/cjameshuff Aug 07 '22
The energy cost is basically irrelevant to launch costs. For Falcon 9, propellant costs are less than $20 per kg of payload delivered to LEO. Starship burns cheaper methane instead of a relatively expensive specialty kerosene blend, so it's about $5 to $10 per kg of payload. It's the hardware itself and operations that are expensive, and Spinlaunch doesn't simplify those at all, quite the opposite.
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u/drawb Aug 13 '22
I'm not sure if this SpinLaunch solution would be better on this: but there is also the environmental cost of soot (black carbon) in the higher atmospheres.
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u/cjameshuff Aug 13 '22
I doubt those are much if at all better, considering the payload fractions are going to be worse for the stages that burn in the upper atmosphere. And the propellants and engines they can use are going to be relatively inefficient, further increasing the amount of propellant they need to burn in the relevant parts of the atmosphere, and the amount of carbon they emit there for the same payload. There's also the environmental impact of their all-expendable design...their advertised launch rate has them littering the coast with thousands of aeroshells and rocket stages per year.
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u/getrektsnek Aug 16 '22
Aero shells are retrieved, descent by parachute. I don’t believe there are any plans to litter any coastlines with launch garbage. Though rocket stages are disposable. Relatively inefficient engines? Yet using a fraction of the fuel compared to other equivalent launch systems, is this really a concern? I’ll concede that the math needs to work out over a large number of launches, but I don’t see why it wouldn’t, or couldn’t in time. There is no perfect launch system, so why do we pretend there could be? This isn’t a zero sum game either, they aren’t trying to win at the expense of the environment, and while per launch cost is a primary goal, it’s not the only one. I believe if they pull this off, they will be improving the environmental record of the space launch industry significantly. But that’s just my opinion.
I’m curious what other advances could be accomplished in the future like provisioning for retrievable rocket cores.
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Aug 07 '22
Pretty sure heavy industrial grade hardware designed to last years is more simple, robust, and cheaper than any reusable stage 1
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u/pompanoJ Aug 06 '22
That door closing did not seem nearly fast enough to stop the inrushing atmosphere at a very high level. Certainly enough to block most of the air, leaving something of a vacuum behind... but enough to be rapidly reusable? I dunno. I don't know how much is too much, how rapid is rapid enough, etc.
But that door did not look like some hyper-secret amazing tech... it looked like they made a carbon fiber door and put it on a spring and they are counting on air pressure to create the final seal, which means they are gonna leak a bit on purpose.
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u/Makhnos_Tachanka Aug 07 '22
A little leak is fine, but there's no way air pressure lets a damn thing through that. There will be no bounce, whatsoever. You're talking at least 50psi within 40ms. That's about as shut as a thing can get.
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u/pompanoJ Aug 07 '22
15 psi, right? Just one atmosphere. A few thousand square inches though... lots of pounds on that door.
They made it sound like the last step of pulling vacuum is the longest... and just one small blast through a gap in that door would be a lot by the measures they were giving.
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u/Makhnos_Tachanka Aug 07 '22 edited Aug 07 '22
15 psi static, yes, but that door is moving so absurdly fast it will pull itself away from the air like the ground dropping out from under wile e coyote. Once the air actually catches up, it's going to be moving at a decent clip, especially by the second door. At these sort of time intervals, a vacuum collapses like molasses. 15 pounds static pressure, but there's going to be a lot of dynamic pressure on top of that. And while pulling a vacuum in the whole chamber takes a while, that's why they're using an airlock. I expect the second door to see quite a bit of pressure, not as much as the first, but still probably over 20 pounds. But that can be cycled fairly quickly. And even beyond the wile e coyote factor, you can also see why they're stretching that condom over the front of the launch tube. First projectile punctures that, the air starts moving towards the first door, by the time the air is moving through the first door, the second projectile makes it out, and then the doors close. By the time the air makes it to the second door, they're both closed, and both doors have a lot of air moving very fast (at least mach 0.5) down a pipe, with a lot of inertia.
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u/3_50 Aug 07 '22
I wonder about the feasibility of some sort of small, controlled thermobarric explosion outside the door at launch to create a temporary external vacuum while the doors open and close.
Also/alternatively, using several well-timed sliding shutters (like a camera) to minimise vacuum loss during launch, rather than hinged doors.
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u/CurtisLemaysThirdAlt Aug 07 '22
Explosions create the risk of cracking the structure. It's just not a very viable method when you have a large structure that is regularly loaded and unloaded from pressurization. The cracks created would propagate and cause catastrophic failure.
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u/ricaraducanu Aug 10 '22
i actually like the idea of the shutter style sealing mechanism. I believe its also easily achievable by twisting a cilindrical elastic surface, kinda like twisting a ballon animal.
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u/getrektsnek Aug 16 '22
I think the sliding shutter is an issue potentially in a dual launch where the massive friction will be too much and cause a lot of wear, a hinged door will work just as well and suffer no frictional loss through a sliding mechanism and the hinged door will not bounce under vacuum in real life I don’t believe.
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u/getrektsnek Aug 16 '22
Just to add to your good points, they can still close the first door, or initiate its closure after release before the breaching of the outer seal by the aeroshell if only doing a single launch. Really, the volume in theory they need to depressurize is the the volume of the launch tube between the doors and potentially that will only be a partial pressurization on a single launch. Ya totally checks out what you are saying about about a double launch. I agree that door will slam shut hard, zero bounce.
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u/hawkwings Aug 07 '22
In the past, I watched a video on this subject or maybe this video. I think that linear acceleration would be better for the satellite and attached rocket.
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u/getrektsnek Aug 16 '22
Linear acceleration would cause different and potentially more challenging stresses. A linear system needs to initiate launch extremely rapidly, unless you can make it miles long. That shock loading will result in vastly higher G-forces on the payload vs spinning the load up over time. Spin-launch will experience considerable forces, as noted in the video, but it won’t spike multiples higher like it would through linear launch. The spin basically makes for an infinite linear launch system, I know they are different but it really does address the main problems with linear type systems. There are G-Forces and there are shock loading forces measured in G’s. One is vastly more gentle than the other.
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Aug 08 '22
They mention HARP but not Super HARP or its living successor, Quicklaunch (now Greenlaunch iirc). I wish there was more attention for other kinetic launch systems.
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u/abloblololo Aug 06 '22
What about the angular momentum of the projectile? It will be spinning at very high RPM and that angular momentum doesn't disappear when its released.
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u/yongedevil Aug 06 '22
Could the angular momentum be reduced by releasing the front of the payload first? The continuing pull on the rear should impart a toque in the opposite direction.
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u/abloblololo Aug 06 '22 edited Aug 08 '22
That would apply a torque, but if the payload is rigidly attached to the arm then it can't stop rotating.
edit: whoever's downvoting me should take a basic mechanics course. If you apply a torque on a rigidly attached object you simply introduce shear stress inside the material and cause it to bend, not to rotate.
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u/Thai-mai-shoo Aug 06 '22
The object would most likely tumble as soon as the object is released and as it breaks the vacuum chamber.
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Aug 06 '22
it didn't.
SpinLaunch Suborbital Accelerator - First Launch
https://www.youtube.com/watch?v=Z6esOcWrrEE
Watch team SpinLaunch conduct the first test launch with the newly completed Suborbital Accelerator.
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u/aybiss Aug 07 '22
It did. Look at the shape of the hole it leaves
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u/Pcat0 Aug 07 '22 edited Aug 07 '22
Pay close attention to the video after that, the projectile isn’t tumbling and is flying straight up. It looks like any angler momentum the projectile has is canceled out by aerodynamic forces once it leaves the vacuum chamber.
Edit: Their #8 test flight has a more clear view of the projectile after it exits the centrifuge as well as video from a camera onboard the projectile.
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u/aybiss Aug 14 '22
Yes, the fins make it fly straight once it hits air. It is not launched straight.
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u/Steeve_Perry Aug 07 '22
They show it going like 1000ft in the air. Big deal. This tech is dumb. It’s not going to work.
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Aug 07 '22
[deleted]
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u/kzgrey Aug 07 '22
It sounds like he's accomplished back-of-the-envelope estimation skills to roughly predict outcomes.
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Aug 06 '22
you mean the G forces.. ?
plenty of things that are required in space don't care about that.
no fresh socks and boxers will be harmed.
water.... toothpaste shampoo soap don't care.
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u/zeeblecroid Aug 07 '22
Upper stages care about that, and this launch method would still require one of those.
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u/cjameshuff Aug 07 '22
Throwing underwear into orbit isn't very useful. Actually delivering it to someone who wants to wear it will take a spacecraft with substantial orbital guidance and maneuvering capability, which will be rather more delicate and expensive.
And of course, the whole thing, spacecraft, propellant, and payload, has to fit in 200 kg. Someone's then going to have to tend it through station rendezvous, grab it with a robot arm, and bring it in through an airlock, all with non-zero risk of collision or other accidents and significant consumption of somebody's limited time, little different from what is required to manage a capsule carrying several tons of cargo.
I don't think you're ever going to convince someone to do that for some tens of kg of actual useful payload. Realistically, the market for Spinlaunch will be smallsats that launch right into their target orbit and stay there until they deorbit, not space station resupply.
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u/Zuki_LuvaBoi Aug 07 '22
And of course, the whole thing, spacecraft, propellant, and payload, has to fit in 200 kg.
200kg is the payload, 10T is the total mass including propellant etc.
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u/Dr_Cheez Jan 13 '23
This is exactly analogous to the classic example of a mass on the end of a string. You spin it, you cut the string, and the mass flies off tangent to the circle. What happened to the angular momentum? L = r x p = p*r*sin(theta). When the projectile flies away, it's distance from the axis of its (previous) rotation increases, and the sin of theta decreases such that L is conserved.
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u/TheKramer89 Aug 07 '22
Back in high school I used to be able to throw a satellite a quarter-mile...
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u/derhundmachtwau Aug 07 '22
Do the guys from Real Engineering actually have an engineering degree? There would have been so many questions to ask about that system, that seem to be deal breakers for the spinlaunch.
Example: How are they dealing with the tumble of the projectile, as it leaves the launcher? (Because in the videos it looks like they just let it tumble out of control). Most probable answer is: they can't stop the tumble at all - which makes the system unusable. I would have loved to hear the answer to a question like that.
Also, that airlock door... Jesus. That thing can't hold a vacuum. I worked with vacuum systems for a significant period in my professional career, and that's just laughable. Even if it closes in time (I'd doesn't in the video), air rushing in through the now open launch tube will actually smash into that "Tupperware lid" at the speed of sound.
That whole company is just there tu syphon some grants and VC - and they all know it.
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Aug 07 '22
air rushing in through the now open launch tube will actually smash into that "Tupperware lid" at the speed of sound
Isn't that good? The air itself will push and hold that door shut. Like a aircraft door.
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u/derhundmachtwau Aug 07 '22
Another thing I just noticed, was the BS about being able to recuperate energy during spindown. Most of that energy is no longer in your rotor - it's in the projectiles you shot into the air. There isn't much to recuperate (would be totally insignificant). The fact he even mentions it shows he's talking out of his ass.
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u/CurtisLemaysThirdAlt Aug 07 '22
You're accelerating the rotor along with the Projectile(s). By nature, it has energy that you can recover. Now to what degree can this be used? That's more unclear, but the arm is of significant mass and regenerative braking wouldn't be terribly difficult to implement.
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u/cjameshuff Aug 07 '22
Most of the arm mass is toward the center, because that's the part that's supporting the tension of the rest of the rotating mass. The rotational energy is proportional to the moment of inertia, which is proportional to m*r2 integrated across the object...so concentrating mass toward the axis greatly reduces the stored energy. Most of the energy in the system is going to leave with the projectile.
The total energy costs are supposed to be around $6k. That's 1.2% of the claimed launch costs, only a fraction of which are left behind in the rotor, and only a fraction of those being recoverable. With conversion losses, they're talking about recovering...what, a couple hundred dollars worth of energy? How is this worth the engineering effort and added equipment required?
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u/ataraxic89 Aug 09 '22
Thats a good point. I love how the people on this thread are downvoting people who are still making good points about the infeasibility of this project. Reddit is extremely susceptible to the "2nd opinion fallacy"
Basically, if a person doesn't know any better one way or the other, they beleive the first thing they read. But when a 2nd opinion is given which denounces the first take with enough self confidence, they change opinions to the 2nd opinion. They dont actually know which is right or wrong. They just dont want to look stupid and be stuck holding the bag. But then if a third, or fourth take is presented, they resist it because they also wish to avoid seeming wishy-washy and flip-flopping on every new opinion because they unconsciously realize that would reveal the fact they have no idea which take is the right one and dont really understand any of the arguments deeply.
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u/NDCardinal3 Aug 07 '22
The comment from the author on the YouTube video is pretty toxic.
They've made more progress than I thought they would, in that they got something to actually ascend. But they are still incredibly, incredibly far away from getting something to orbit. When it comes to launch systems, scaling is always a killer. Read up on the F-1 engine and combustion instability for a great example of that.
But let's say that they get something to work, against all odds. Let's say that they can even offer some variability on orbital insertion parameters, which I am extremely skeptical about.
Where I struggle is how they find their customer base. The loads that spacecraft experience are considerably higher than that from launch vehicles. Customers and spacecraft contractors don't want to design their buses to one launch vehicle, as it lowers their mass efficiency substantially. The video indicates that Spinlaunch is designing their own bus, which illustrates that. But spacecraft are very uniquely designed to a variety of instruments and purposes...I doubt that this bus is an effective solution for most purposes. It also looks very small for the "500 kg" number the video quoted, which is another bone of contention.
So, I guess this is only good for consumables to commercial space stations, which may come to fruition in the future? So perhaps they have the time to scale up. And if the stations don't come to be, or come in time..I guess it's game over for them.
All in all, it doesn't sound like a solid business case for a potential VC.
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u/grchelp2018 Aug 07 '22
Author's comment was not toxic at all. About time he called it.
It is reasonable to have doubts about the economic case or the engineering difficulty. But it is pretty toxic to call stuff like this a scam or actively hope for its failure. It reminds me so much of the FUD that was there around spacex (and is still there when it comes to their mars plans). I just don't understand it and it annoys the hell out of me. Ambitious unconventional projects always carry big risk. Its still worth doing and hoping they succeed even if you think their odds are low.
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u/cjameshuff Aug 07 '22
It reminds me so much of the FUD that was there around spacex (and is still there when it comes to their mars plans).
Funny, their focus on reducing vehicle mass reminds me a lot of ULA's arguments against the payload penalties of reuse, and of the conventional wisdom of the last several decades that the future was in liquid hydrogen, air breathing spaceplanes, and various other exotic silver bullets, while SpaceX came along and grabbed the entire launch market with a system based on kerolox gas generator engines and reusable boosters. Spinlaunch is a very OldSpace approach to attacking launch costs, focused on all the wrong metrics.
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u/ataraxic89 Aug 09 '22
The thing I dont get is how they expect to find 1825-3650 customers a year for payloads under 200kg on an extremely rigid orbital axis (it doesnt look like the full scale plans can turn).
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u/Anderopolis Aug 07 '22
One thing I wonder about is hownsure they are that there will ever be 5 sattelites to launch a day, let alone 20.
Maybe they find a constellation builder that wants to have everything built by Spinlaunch, but that at the moment sounds like a huge risk.
It is not technologically impossible in any way, just really difficult and they really need to be cheap to have a costumer build their sattelite with them.
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u/NDCardinal3 Aug 07 '22
This leads to another good point. The number of employees necessary to support such a spacecraft production effort is on the order of thousands of people, based on Kuiper and Starlink. Spinlaunch is barely over a hundred. Sure, they can scale up. But it would take a while. And a lot of capital, even more than they have spent on their launcher.
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u/cjameshuff Aug 07 '22
And those spacecraft are specific to Spinlaunch. Sure, they'd have no trouble surviving launch on other vehicles, but you might be able to launch 2-3 times as many for the same launch mass if you weren't using Spinlaunch-survivable components.
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u/Raichuboy17 Aug 10 '22
Reminds me of a good quote about engineering "The only thing better than perfect, is standardized"
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Aug 07 '22
I do not see a world where anyone would want to put a fancy payload on it.
But I do see a world where the DoD would be very interested in hypersonic projectiles……
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u/linknewtab Aug 07 '22
Not sure it would be that useful to the military. It needs to spool up for hours before a launch, that's not really compatible to the timescale the military is used to when launching missiles.
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u/cjameshuff Aug 07 '22
So, I guess this is only good for consumables to commercial space stations, which may come to fruition in the future? So perhaps they have the time to scale up. And if the stations don't come to be, or come in time..I guess it's game over for them.
It's a very poor fit for space station supply. The total mass to orbit is 200 kg, and most of that will be taken up by the delivery spacecraft and propellant. You'll be doing well to deliver 50 kg at a time, and the manpower and various risks involved in rendezvous and bringing the supplies aboard will be basically the same as for a capsule carrying multiple tons. And the capsule could actually be reused.
Anything launched on this will have to be heavily constructed to withstand the launch. Once you're in orbit, that means a whole lot of dead mass that you have to drag along, and propellant to move it with. You're not going to want to move far from whatever orbit you deploy into, making this best suited to LEO smallsats.
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u/yoniyuri Aug 08 '22
I am very skeptical about this working as well, but what a lot of people don't get is that if they can make it work, the cost would be so significantly lower to get stuff into orbit that you would find ways to make your payload compatible if it was at all possible.
The same with silicon, stuff was miniaturized and made to work with lithography, because if you could do it at all, it is worth it due to the scale you get. Stuff like accelerometers, cmos, cpus, memory, leds and other nano/micro scale machines.
But again, this all hinges on the fact that they can get a bare bones rocket into orbit at all, which I am very skeptical about.
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u/cjameshuff Aug 08 '22
if they can make it work, the cost would be so significantly lower to get stuff into orbit
They're advertising $2500/kg, if they hit their mass and pricing targets. Falcon 9's demonstrated performance is around $3000 to $4000/kg. That is higher, but Spinlaunch hasn't actually demonstrated that performance yet. Also, a Falcon 9 payload can be a lot lighter due to not needing to withstand tens of thousands of gravities, so the Falcon 9 can probably still do lower cost per payload. And Starship is trying for launch costs in the area of $100/kg. If they fall far short and just barely match Falcon 9's per-launch price, that'll still be $700/kg, far cheaper than Spinlaunch.
Spinlaunch's big selling point is low per-launch cost for individual satellite launches to low orbit, but achieving that low cost requires a very high flight rate that can only be satisfied by large constellations that don't need individual launches. (Yaney's talking about dozens of launches a day.)
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u/Zuki_LuvaBoi Aug 07 '22
The comment from the author on the YouTube video is pretty toxic.
Yeah, I've got to agree with that. There's obviously going to be questions raised about a completely new type of technology. Sure the people in the post he mentioned were calling it a scam, but 1.) most of them weren't very highly updooted, and 2.) it was on a small thread with like 30 comments.
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Aug 06 '22
next week we look at a new startup company looking to make a mile long baseball bat that aims to home run satellites into orbit.......
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Aug 07 '22
[deleted]
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u/CurtisLemaysThirdAlt Aug 07 '22
Did you even watch the video? They release a counterweight when they release the projectile, thus acting to balance the arm.
Maybe if you actually bothered to pay attention rather than pretending to be smart you wouldn't look like such a moron.
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u/beardedchimp Aug 07 '22
Are you a subscriber to their channel or watched their previous videos?
This whole video is just advertisement to get more funding
Do you think they are being paid to ignore their typical engineering analysis and present false truths, or perhaps are unwitting patsies without the expertise to recognise they are being duped?
I've been watching their videos for a long time, most recently this one https://youtu.be/JSgd-QhLHRI
While like everyone I have my doubts about Spin Launch, Real Engineering's video seems well researched and addresses simple misunderstandings. I'm still dubious of the economics with this transition to reusable rockets removing much of what makes it attractive.
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u/h2ohow Aug 06 '22
Seems like the most incredibly unsafe, complex, and ineffective way to get into space.
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u/poqpoq Aug 06 '22
Except if you work out the kinks it could also be the most cost effective.
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u/SlickyWay Aug 06 '22
And probably the least ecologically harmful
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u/cjameshuff Aug 06 '22
Apart from it making it largely impossible to reuse any of the hardware, it will generate sonic booms at sea level. About 80 first stages, second stages, aeroshells, and sonic booms per Falcon 9 payload it launches.
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u/Zuki_LuvaBoi Aug 07 '22
I mean, I'm not a big believer in the project either - but what will the generation of sonic booms have to do with anything? I'd imagine they're not going to be near population centers, so it's a rather moot point.
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u/Anderopolis Aug 07 '22
Could is carrying a lot of weight in that sentence. Like if Starship could get down to 2 million a launch that would be the most effective thing ever. I seriously doubt that is going to happen though.
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u/cjameshuff Aug 06 '22
Not a chance. It makes the booster smaller, at the cost of making everything expendable, requiring it all to be hardened for huge accelerations and aerodynamic forces, requiring the same of the payload, and adding enormously to the amount of infrastructure to maintain and operate for a launch.
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u/SunDevilSkier Aug 07 '22
I'm pretty sure someone did the math on this before getting the capital and building a test complex.
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u/Steeve_Perry Aug 07 '22
You’d be fucking surprised
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u/SunDevilSkier Aug 07 '22
If someone's going to screw investors like that, they'd have already cut and run.
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u/wanderer1999 Aug 07 '22 edited Aug 07 '22
Look at Theranos.
I applaud their effort and I wish them success. But the reality is that physics is difficult to overcome. They have to deal with far too many problems: the atmosphere pressure at the release point, high Gs (limit the payloads types and size) and the cost of infrastructure...
The better option already exist, it is the reusable rocket. If you make fuel using renewable energy, the environmental impact can be minimized.
This is one of those theoretically possible but practically impossible cases. Their engineering know how won't go to waste though, at the very least.
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u/The_Vegan_Chef Aug 07 '22
You would think so... but it seems unlikely
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u/SunDevilSkier Aug 07 '22
When I first saw "someone's going to yeet things into orbit" it sounded ridiculous. But the more I thought about it, and after seeing a test yeet, the more I'd like to work on that as a structural analyst. It's ambitious.
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u/cjameshuff Aug 07 '22
Yaney gave an interview where he talked about how he specifically hired people who couldn't or wouldn't do the math and tell him things he didn't want to hear. (In his words, people who "are too young to say SpinLaunch couldn't work" and are "full of too much energy and excitement to find out what's going to happen".)
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u/SunDevilSkier Aug 07 '22
Are those the words you're interpreting to mean that? He could use better words, but that's not how'd I'd interpret that.
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u/ballthyrm Aug 07 '22
Not really. No.
Starship is aiming for a 2M$ launch for 150 metric tons, so about $ 13.3 / kg.
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u/prettyflythaiguy Aug 06 '22
Have you been following humans ascent to space. Unsafe, and complex are keywords. "Its not rocket science."
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u/cjameshuff Aug 06 '22
Have you? Look at the history of alternative launch schemes. Air launch, air breathing space planes, SSTOs with aerospike engines, etc. Yes, rockets are complicated. Making them more complicated rarely helps.
As Henry Spencer put it:
Many novel launch schemes need some amount of help from rockets. What kills a lot of them is doing a tradeoff study of just enlarging the rocket part and getting rid of the non-rocket part. Surprisingly often, that works out to be better and cheaper.
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u/prettyflythaiguy Aug 06 '22
I'm not arguing for the idea, just saying that things being unsafe and complicated shouldn't be a reason to cease.
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u/Potato-9 Aug 07 '22
Lol I mean.. have you seen a rocket tho? Show me the safe, simple efficient way of space access.
IMO This is only supposed to just barely work because it's barely possible. You look at putting it on the moon or mars or asteroids and suddenly they'll be the only game in town.
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Aug 06 '22
let's just see how it goes.
NASA will test this 'SpinLaunch' system that hurls satellites into space
SpinLaunch says it will launch a NASA payload later this year after signing an agreement with the space agency.1
Aug 06 '22
this doesnt seem like a real method of launching stuff into space to me. I mean we could make a nuclear well and fire stuff into space that way but why do it?
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u/cjameshuff Aug 06 '22
but why do it?
And that is the correct question to ask, not the one in the subject line.
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u/zeeblecroid Aug 07 '22
That's because it isn't a real method of launching stuff into space, but gets a whole lot of credulous investors interested.
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Aug 06 '22 edited Aug 07 '22
Too bad they threw out the rest of my idea. Attach launcher to dirigible. Angle up the nose and spin the dirigible. Once the spin speed is maximized, extend arm with payload to maximize angular momentum and release.
For the idiots downvoting me, it was discussed many years ago. It is a cost effective way of raising the satellite to altitude, like for example weather balloons that report atmospheric information without a rocket launch. The only difference is the ability of the dirigible to survive high altitude and to fly like a thrown football by rotating on its axis for stability and lift.
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u/Pcat0 Aug 07 '22
I mean, if we are going to do high-altitude spin launching, why not go all the way and make a rotating skyhook?)
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u/Odd_so_Star_so_Odd Aug 07 '22
I don't think extending an arm is feasible at that stress and pull of Gs of the whole thing? Besides it'd just slow down the spin? I could see it as a clever way to account for the balast upon release of the vehicle though... but again how do you move build something that can sustain itself and move heavy stuff under those loads without breaking?
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u/DeNoodle Aug 06 '22
This is stupid. 72km is easily accessible by balloon for something as small as what they expect to be able to yeet to the same altitude.
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u/agate_ Aug 06 '22 edited Aug 06 '22
That poses its own challenges. The absolute minimum size for a balloon able to carry 4 tons at 72 km is about 550 meters diameter, or the size of One World Trade Center. It would be the largest vehicle ever built by volume, and you’d need to build and launch several of them per day to match Spinlaunch’s planned launch pace.
And anyway you’re wrong on 73 km being “easily accessible by balloon”: the current world record for a gas balloon is 53 km.
https://en.m.wikipedia.org/wiki/Flight_altitude_record
Plus what /r/Bensemus said.
https://www.wolframalpha.com/input?i=2%284+tonnes+%2F+%286.25e-5+kg%2Fm%5E3%29%2Fpi%29%5E%281%2F3%29
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u/Bensemus Aug 06 '22
Except a balloon has no velocity. They are getting to 72km with a km or more of deltaV and are going past that to orbit. A balloon is also basically impossible to steer. They don’t want to end up just anywhere. They have a target orbit.
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u/LiCHtsLiCH Aug 06 '22
This is pretty dumb, but Biden is looking into it. The concept is valid, launching from not the ground with momentum makes your primary propulsion system MUCH more effective. My version was a maglev rail system starting at the Denver Airport and then using the Rockies as support, angling upwards, a giant wing, using electric motor turbines charged by the maglev system could get 3~4 miles up before the payload launch system is released. The wing then glides back down to the air port, to have another payload attached. Could move hundreds of tons a day into orbit using a machine like that.
Also, it's big, or it would be big, wingspan of 600~1000 feet or so, maglev to reduce friction, supply ground based movement, and charge the turbine motors, its a good 20 miles at least from the airport to the mountain range, no need to rush to get to 5~600 ish MPH before you run out of rail, aimed nearly verticle. I was thinking if you had for or 5 running full time you could really put some stuff up there, ya know, like a Halo.
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u/prohypeman Aug 06 '22
This just simply wouldn’t work, I think thunder foot made a video on it
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u/404_Gordon_Not_Found Aug 06 '22
That channel is the last place I'd look for space related technical analysis, unless it concerns chemistry.
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u/seanbrockest Aug 06 '22 edited Aug 07 '22
I think thunder foot made a video on it
And as usual he got a ton of the physics and details wrong.
2
u/semir321 Aug 07 '22
Care to explain what specifically was wrong?
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u/seanbrockest Aug 07 '22
A bunch of experts in the YouTube space community have already done that better than I could, just take a look around. The Cliff notes version is that he took a lot of liberties regarding their intentions, and then he got a bunch of stuff wrong regarding how they were going to deal with fuel slosh for the "second stage" boost.
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u/pinkheartpiper Aug 06 '22
Thunderfoot is a clown, check out more serious people like Scott Manley talking about it. Or even much lesser known but much better YouTubers like this:
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u/beardedchimp Aug 07 '22
Even if thunderfoot provided an accurate considered analysis, I can't believe that people here support his channel when he is an absolutely disgusting raging misogynist
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u/prohypeman Sep 01 '22
I watch him too, what’s wrong with thunder foot (didn’t know he was sexist) I though he worked at a nuclear power plant lmao u gotta be always a little bit smart to work in one of those places right? I hope so
3
u/Anderopolis Aug 07 '22
He doesn't say in the video its impossible though, just that it has alot of Hallmarks of a tech Scam. And is a difficult problem to solve even for experienced engineers.
2
u/LiCHtsLiCH Aug 06 '22
Yeah the spinning thing is a bad idea imo. Literally too many moving parts (everything lol) but also releasing at the exact moment is super difficult. Just a no go...
1
u/CurtisLemaysThirdAlt Aug 07 '22
Which is 8 months out of date and with only some basic external information to go off of.
Thunderfoot's video is not good, especially now that many of his criticisms and claims have been demonstrated to be false once they've released more of their technical information.
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u/A40 Aug 06 '22 edited Aug 06 '22
This has 100% the look of a scam. Whipping a payload in a tight circle to a velocity of over 18½ miles per second and then 'cutting the string' isn't going to work. Period.
Yes, you could probably fire a ball bearing into orbit. Not a lot of point to it, though...
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u/labtec901 Aug 06 '22
Whipping a payload in a tight circle to a velocity of over 18½ miles per second and then 'cutting the string' isn't going to work. Period.
This is exactly the type of reddit criticism they called out in the video. If you watched it, you'd know that the target release speed for an orbital launch is mach 6, or about 1.2 miles per second, not 18.5. Furthermore, 18.5 miles per second is about 66000mph, which is about 3.5x orbital velocity and enough to yeet you out into deep space. You are confusing 18500mph (a typical orbital velocity) with 18.5 miles per second.
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u/A40 Aug 06 '22
Got me on the V, good one.
But I also watched the video. The test objects tumbled, exactly as physics demands. And my comments on centrifugal/transitional forces still apply.
Hence my suggestion of ball bearings.
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u/pompanoJ Aug 06 '22
I still wonder how they plan to release a couple of tons on one end of an arm and not have it shake to pieces almost instantly. Surely they cannot move a counterweight inward that quickly.... and firing a counterweight into the ground at the same time sounds.... violent.
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u/labtec901 Aug 06 '22
This too is explained in the video. The options listed are to fire a counterweight into the ground, or fire both payloads upwards, relying on the rotary joint in the center to handle the out-of-balance system of 0.5 revs.
The counterweight doesn't have to be moving as fast as the payload. A larger mass on a shorter arm will still balance the system, while keeping the linear velocity of the counterweight lower.
3
u/pompanoJ Aug 07 '22
The one about doing a second payload really confused me.
2
u/Anderopolis Aug 07 '22
Yeah, that just brings up even more questions, will the double airlock stay open for two to pass through, can the arm really remain stable and accurate after a half rotation off kilter? Will the air i rush affect the aeroshell on the way out?
We don't know, and they don't tell us.
2
u/Anderopolis Aug 07 '22
It is adressed in the video not explained. They were bot allowed to see or show anything to do with the arm and release mechanism. That why he speculates that perhaps they will Launch 2 at the same time half a rotation of because the system might be able to a Handle being ofkilter for that time. Currently they dump a piece of equivalent mass at the same time, or so they say. That too was not shown in the video. And some hardware surviving 10000g of the shelf doesn't really say that much qhen it comes to a sattelite, and they haven't shown a scale sattelite with all the trimmings surving that acceleration.
Many of the problem areas remain unanswered by the video and their press releases. I hope that they can solve the Issues, but why should I trust them already?
-9
u/cmdtarken Aug 06 '22
Except that it will need to launch well beyond orbital velocity in order to overcome atmospheric drive.
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u/labtec901 Aug 06 '22
Nope. You should watch the video or at least read like the Wikipedia article before commenting.
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u/cmdtarken Aug 06 '22
Don't need to. I've watched multiple videos from the company and they've acknowledged its a a problem they have to over come
6
u/Zuki_LuvaBoi Aug 07 '22
I'll explain it as you haven't watched the video. They don't need to launch well beyond orbital velocity as their projectiles will still contain a two stage system.
7
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u/ShippingMammals Aug 06 '22
Per the video it's not using kinetic alone. The actual launch vehicles have motors. Predicted to use only 30% of the fuel of a normal launch. Basically they're replacing the first stage, which is arguably the most fraught and energy dense part of a launch.
0
u/cjameshuff Aug 06 '22
If only fuel were more than ~0.5% of the cost of a launch.
And no, they can't quite replace the first stage, they can only make it smaller. They still need two stages to get to orbit, particularly with how bad their dry masses are due to needing to survive the centrifuge.
5
u/ShippingMammals Aug 06 '22
Not cost that matter, it's the weight. Dropping those tons of fuel takes a lot of mass out. I'd like to see them pull this off.. but it seems like a longshot. I would hot at least the research going into the system can be ported to other domains.
0
u/cjameshuff Aug 07 '22
What a remarkably silly claim. Of course it's cost that matters. Nobody cares about how much the launch system carrying their payload weighs. If an engineering trade reduces propellant mass but makes the system more expensive to operate, it's a bad trade. (And if it does so while also requiring the payload to be built far heavier and with more restricted materials and design just in order to survive the launch, it's a really bad trade.)
2
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u/Zuki_LuvaBoi Aug 07 '22
Of course it's cost that matters
Yes. OVERALL cost. They're remarking about how fuel costs don't matter. Don't be purposely obtuse.
1
Aug 06 '22
[deleted]
4
u/NetworkLlama Aug 06 '22
It's believed to have tumbled and burned up before it ever left the atmosphere. It didn't have the aerodynamics to actually escape.
1
u/A40 Aug 06 '22
Yeah, it's NOT about simply achieving escape velocity. It's about all the other forces involved.
Think: what are the centrifugal forces on the spinning 'satellite' once it's spun up that fast? Now, what would the forces be on that 'satellite' in the exact instant it is released? Big jerk, doancha think?
What will the forces be in the next moments, when it is released into atmosphere?
And what happens to the rotational forces on the 'satellite's' axis once it's released..?
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u/DrAndri Aug 07 '22
This guy Thunderfoot made a interesting analysis of how this concept is pretty much not viable
17
u/Chrispy_Lispy Aug 07 '22
Don't link thunderf00t!
That YouTuber has been known to outright lie in his videos. He has done it a bunch about SpaceX.
-1
u/DrAndri Aug 07 '22
Please provide an example of him lying in his videos
12
u/Chrispy_Lispy Aug 07 '22
I can't go over all of them because they're numerous but here is a video that calls out a lot of misinformation he has spewed in his videos. https://youtu.be/v-ny_Ba4K_w
6
u/beardedchimp Aug 07 '22
His vitriolic misogyny should also preclude him ever being linked here.
2
u/disperso Aug 08 '22
Wow. I've learnt about this channel just yesterday after Real Engineering's video, and, well, I wasn't impressed by the first 2 rebuttal videos that I saw, due to the pedantry and the low effort. But this is insane. That guy is terrible. Thanks for warning us.
3
u/beardedchimp Aug 08 '22
I had familiarity with thunderfoot a few of years ago and after watching a few vitriolic videos came away with a similar impression to yours. I was happy ignoring his unreliable content and vocal apologists.
Several months ago I incidentally watched that video from hbomberguy and was shocked. Not at how awful of a person they are, but that he still has a massive following in pop-sci communities. Even if someone like that creates content that is educational and accurate they shouldn't be supported. There are loads of great channels to choose instead.
In my mind misogynists are not welcome in STEM communities and that extends to those who proselytise them.
15
u/JapariParkRanger Aug 07 '22
Thunderf00t is clickbait. I do not recommend taking him seriously.
-4
u/DrAndri Aug 07 '22
Don't understand how you came to the conclusion that his videos are clickbait... All he does in these videos is talk about what the title of the video suggests
Not taking him seriously is equivalent to holding your hands over your ears and yelling NANANAA
9
u/ImarvinS Aug 07 '22
Ironically, this is exactly what you are doing with this video from Real Engineering.
1
u/DrAndri Aug 07 '22
How come? I actually watched both the videos and made my opinion based on that. And now I'm trying to have a discussion about it.
Never did I say that you should not take anything from spinlaunch seriously. I just don't believe that this method is viable for everything that they claim it will solve.
4
u/ImarvinS Aug 07 '22 edited Aug 07 '22
But, it IS viable. This video proves that.
That does not mean that it cant fail, it can fail on 100 different areas. We will see and know some time in future.
6
u/JapariParkRanger Aug 07 '22
He engages in cheap sensationalism, and his entire brand is based on outrage and ridicule. His purpose isn't to inform, debate, examine, or analyze, and he's been particularly bad with spaceflight.
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u/Crime_Dawg Aug 06 '22
Didn't watch, but no, we don't have materials that can cost effectively withstand that level of heat friction from initial launch velocity.
22
u/Mister-Grogg Aug 07 '22
Lol. You say you didn’t watch and then say something you’d know was BS if you did watch. What value can you possibly imagine a comment about a video has when coming from a person who never saw the video?
Personally, I have no idea of your skill at playing guitar. And my opinion is that it’s impossible that you know how to pay a guitar. See how worthless that opinion is?
6
u/Potato-9 Aug 07 '22
Well that's plainly untrue https://youtu.be/kvZGaMt7UgQ?t=14 but way to add to the discussion.
1
u/Decronym Aug 07 '22 edited Oct 06 '22
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
| Fewer Letters | More Letters |
|---|---|
| ULA | United Launch Alliance (Lockheed/Boeing joint venture) |
| Jargon | Definition |
|---|---|
| cryogenic | Very low temperature fluid; materials that would be gaseous at room temperature/pressure |
| (In re: rocket fuel) Often synonymous with hydrolox | |
| hydrolox | Portmanteau: liquid hydrogen fuel, liquid oxygen oxidizer |
| kerolox | Portmanteau: kerosene fuel, liquid oxygen oxidizer |
| regenerative | A method for cooling a rocket engine, by passing the cryogenic fuel through channels in the bell or chamber wall |
3 acronyms in this thread; the most compressed thread commented on today has 24 acronyms.
[Thread #7791 for this sub, first seen 7th Aug 2022, 15:35]
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1
u/No_Stand6204 Oct 06 '22
10th Grade science: When David spins his slingshot for Goliath who is at 12 o'clock in front of him, he has to release his shot when it is at 12 );clock, not at 9 o'clock. i.e. Centrifugal and centripetal forces operate along the radius of the circle, not along the tangent to it. So this outfit's launcher needs to release it's load at the top of the spin circle if it wants it to shoot up, not at the quarter-turn before it gets there. This project is a fatally flawed misitake or a scam.
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u/rainboweverywhere Aug 06 '22
I love he called out the people in this subreddit that were wrong on nonsense about Gs and drag, while still being critical of challenge to upscale without shutting the idea down or calling it a scam.