Spinlaunch... Can it succeed?

[DougSpindler]

I doubt if you could get half a dozen spinlaunchers on top of that truck, so if you only had one you wouldn't be able to fire them all off at once (or in quick succession).

They could have used an arm launcher, like what's been used for baseballs.  (We had one of these in school.)  Just load up a basket of grenade and the arm would toss them.  Problem is the limited range.  A ballistic launch or rocket launch would require less energy and travel farther.

[PlainName]

They could have used an arm launcher

That's nothing like a spinlauncher though. Short throw == high acceleration, low velocity. The whole point of spinlaunch is it builds up over a relatively long time. No massively instant power source, like explosives or rockets or elastic bands, required.

[DougSpindler]

They could have used an arm launcher

That's nothing like a spinlauncher though. Short throw == high acceleration, low velocity. The whole point of spinlaunch is it builds up over a relatively long time. No massively instant power source, like explosives or rockets or elastic bands, required.

The amount of energy required to get an object in orbit is the same no mater how it is propelled.  The challenge is to find a way that's more efficient than a rocket. 

Something I did not realize is they are spin launching a rocket to 200,000 feet.  The way rockets are made now the skin is so thin the fuel in the tanks adds to the structure of the rocket.  And that force for the most part counteracting gravity.  In order for them to launch a rocket the skin of the rocket I think would have to be very thick to withstand the changing force vectors when spinning it just would be impractical. 

I would think launching from a hydrogen balloon might be more a better idea.

The folks at NASA are no dummies.  I'm sure there's a reason they are using rockets.   

[Rick Law]

...
The amount of energy required to get an object in orbit is the same no mater how it is propelled.  The challenge is to find a way that's more efficient than a rocket. 
...
In order for them to launch a rocket the skin of the rocket I think would have to be very thick to withstand the changing force vectors when spinning it just would be impractical. 
...

re: "The amount of energy required to get an object in orbit is the same no mater how it is propelled. "

That is almost true but not entirely.  The amount of energy added to the object is the same, but the amount of energy expended is not the same.  Like charging a battery, you consumed more AH than the AH stored in the battery.

These two entirely different ways of launching, rocket vs spinning, will be "wasting" energy differently.  Take air drag for example.  Air drag is proportional to V².  So at 2x the speed, your lost to air drag is 4x.

A rocket accelerating slowly from the ground has very low V, the atmosphere is thick near ground, but V is very low.  When the rocket reach high velocity, the rocket is higher in altitude where the air is thinner, so less air to create drag up there.  It may waste less due to air drag, but then of course the rocket is carrying the fuel (and container) that it will burn away or discard and that is a lot of waste.

Spinlaunch is the other way around.  It doesn't carry any fuel it needs to accelerate, no waste there.  But on launch, it is at its highest velocity where the air is thickest, and slows down by air friction and earth's gravity - till it reach the altitude to light it's own rocket.  So the launched vehicle needs to have a lot more initial energy (velocity) to deal with the lost as it goes up.  While it was spinning on the ground before launch, it is wasting energy dealing with the friction of the spinning mechanism...

The other issue is the necessity to harden the payload object to deal with the 11,000g centrifugal g.  Your payload object may be 1kg for a rocket launch, by the time you harden the design of that 1kg object to deal with the 11,000kg centrifugal force, your spin launch object now may be a many folds heavier 1kg.  So, too complex to compare theoretically.  We may well have to wait until they actually do launches to see how much efficiency it actually gained, if any.

[DougSpindler]

too complex to compare theoretically.  We may well have to wait until they actually do launches to see how much efficiency it actually gained, if any.

That's the right answer.

I'm wondering why they didn't build their launch facility in Denver where the air is thinner.  I tried to find where they are launching from/altitude, but wasn't successful.
You are right about the rocket, as the rocket is accelerating burning fuel the mass continues to decrease.  It's just hard to fathom the spin launch working and being less costly.  Escape velocity from the surface of the Earth is 25,020 mph/40,270 km/h. 

Hard to believe they can get a mass spinning fast enough so it's traveling at 25,020 mph to a height of 200,000 feet.

I wonder if before going into business if they consulted a physicist who has extensive knowledge in this area.   

Remember the guy who founded spinlauch has no experience with rockets or satellites.  Apparently like Elizabeth Holmes and Trevor Milton you don't have have any knowledge about the technology, just the idea is all it takes to get funded these days.

[Rick Law]

Hard to believe they can get a mass spinning fast enough so it's traveling at 25,020 mph to a height of 200,000 feet.
...

Forget spinning it escape velocity.

For a 100meter diameter spinner to launch at earth escape velocity (25020mph or 11186m/s), the spinning centrifugal g-force would be a cool 255,360g.  According to wired.com, Spinlaunch is thinking 100kg payload.  That 100kg payload would have 25,536,000kg centrifugal g-force.

[DougSpindler]

Hard to believe they can get a mass spinning fast enough so it's traveling at 25,020 mph to a height of 200,000 feet.
...

Forget spinning it escape velocity.

For a 100meter diameter spinner to launch at earth escape velocity (25020mph or 11186m/s), the spinning centrifugal g-force would be a cool 255,360g.  According to wired.com, Spinlaunch is thinking 100kg payload.  That 100kg payload would have 25,536,000kg centrifugal g-force.

Oh, when you put it like that I have no doubt some guy who knowns nothing about Physics, launching satellites or orbital mechanics will get billionaires to invest in his idea.  I suspect he won't get one physicist to invest.   

[Nusa]

Hard to believe they can get a mass spinning fast enough so it's traveling at 25,020 mph to a height of 200,000 feet.
...

Forget spinning it escape velocity.

For a 100meter diameter spinner to launch at earth escape velocity (25020mph or 11186m/s), the spinning centrifugal g-force would be a cool 255,360g.  According to wired.com, Spinlaunch is thinking 100kg payload.  That 100kg payload would have 25,536,000kg centrifugal g-force.

Why forget something that was never planned? Escape velocity has never been the goal. So everything you just said is meaningless as an argument.

Orbital velocity is a MUCH lower number. Plus the spinlaunch first stage isn't even intended to do that. The rocket on the payload after dumping the mass of the atmospheric shell would do the final controlled insertion into orbit, in the traditional manner.

[Nusa]

too complex to compare theoretically.  We may well have to wait until they actually do launches to see how much efficiency it actually gained, if any.

I'm wondering why they didn't build their launch facility in Denver where the air is thinner.  I tried to find where they are launching from/altitude, but wasn't successful.

You didn't try very hard. The search keywords are "spinlaunch location". Which happens to be nearly as high as Denver anyway.

[DougSpindler]

too complex to compare theoretically.  We may well have to wait until they actually do launches to see how much efficiency it actually gained, if any.

I'm wondering why they didn't build their launch facility in Denver where the air is thinner.  I tried to find where they are launching from/altitude, but wasn't successful.

You didn't try very hard. The search keywords are "spinlaunch location". Which happens to be nearly as high as Denver anyway.

Where is it located?  All I could. Find was New Mexico.

[EEVblog]

Remember the guy who founded spinlauch has no experience with rockets or satellites.  Apparently like Elizabeth Holmes and Trevor Milton you don't have have any knowledge about the technology, just the idea is all it takes to get funded these days.

I'll just drop this here 

[DougSpindler]

That was Meredith Perry in 2012.

And here she is in 2018.  After repeatedly missing self-imposed deadlines for progress on its wireless charging-at-a-distance phone case, uBeam’s CEO Meredith Perry has decided to shift out of the CEO position and into a board member and senior advisor role. She’d founded the company in 2011 from her dorm room and brought in over $40 million in funding by selling a wide range of elite investors on her vision for a cordless future, including Andreessen Horowitz, Founders Fund, CrunchFund (disclosure: started by TechCrunch’s founder), Marissa Mayer and Mark Cuban.

Now I probably took the same physics class she did in college and would have been able to tell here it would work, but like with the company selling nuclear batteries it would take 500 years just to charge her iPhone.  With ultrasonic waves at 3 feet I’m guessing 1,000 yers?

It’s amazing how much money is being thrown at kids who think they can make a product which violates the laws of physics.

[PlainName]

That was Meredith Perry in 2012.

And here she is in 2018.

Seems to have worked just fine. For her

[DougSpindler]

That was Meredith Perry in 2012.

And here she is in 2018.

Seems to have worked just fine. For her

It does.  After having studied paleobiology and astrobiology at the University of Pennsylvania and conducted astrobiology research she's now founded a new company which is developing a new neurotechnology, and subsequently announced in 2020 a new company co-founded for this purpose, Elemind Technologies.  Apparently having have been educated in paleobiology and astrobiology make one in expert in medicine and neuroscience. 

She sure knows how to market herself and receive awards.  Perry was recognized as one of Fast Company's "Most Creative People", has been included in Fortune’s “40 Under 40” Mobilizers, Forbes’ “30 Under 30” and Vanity Fair’s “The New Establishment”. Perry is the recipient of ELLE Magazine’s Genius Award.

I'm not trying to dump on this women, but she's college educated and sure seems case of anything is possible if you think it can be done. At UC Berkeley there was a very smart wonderful professor who tell students Meredith some ideas are about as good as a shovel with a rope for a handle.  Meaning it might be a clever idea and it might be possible, but that doesn't mean it will be practical.  He would then encourage students to think about the physics and engineering of their idea.

She appears to be another Elizabeth Holmes in the making.  I have an idea, can we make the Elizabeth Holmes award?  The winner would be a college student who can dupe the press and investors about an idea they have which violates the laws of physics or we are far from having the technology from making it possible.  Would this be going too far?  Saying they have to be attractive white women wo are seeking funding from rich white guys?

[fourfathom]

Funny, I was just trying to find any news about Perry's trial and came up with nothing.  Then I realized that the trial I was thinking of was for Holmes!  I suppose one big difference between these two is that Holmes (allegedly) deliberately lied to investors, customers and, even falsifying test results given to patients.  Perry just spent a lot of other peoples money trying to make something work.  Of course, it never had a chance of working as she promised, but she didn't put people's lives at risk. 

[Rick Law]

Hard to believe they can get a mass spinning fast enough so it's traveling at 25,020 mph to a height of 200,000 feet.
...

Forget spinning it escape velocity.

For a 100meter diameter spinner to launch at earth escape velocity (25020mph or 11186m/s), the spinning centrifugal g-force would be a cool 255,360g.  According to wired.com, Spinlaunch is thinking 100kg payload.  That 100kg payload would have 25,536,000kg centrifugal g-force.

Why forget something that was never planned? Escape velocity has never been the goal. So everything you just said is meaningless as an argument.
...
...

Well, I did the math because Doug was talking about launching with escape velocity.  After I did the math, I looked at the numbers and I want to pitch that to the investors first, so I need everyone to forget about seeing my reply.

What I am going to pitch to investors will have nothing to do with launching, I will pitch something else instead:

Once I get a wheel going at mach 33, I have a g-force of 255,360g.  You must have already see spinning wheels, that is a simple concept.  I just have to make it go a bit faster.

You see, diamonds take just over 1000 centigrade at about 730,000 pounds per square inch pressure to form.  So, instead of launching anything, my wheel will be spinning a bucket of graphite with a few slaps of iron on top.  Takes a mere 3 pounds of iron for every square inch and I have 3*255,360g = 766,080 pounds per square inch.  We don't even have to worry about the 1000C, we'll let a bit of air in and let air friction do the heating and we have a bucket of diamonds just like that.  The whole concept is so simple, practically all I need to do is to choose the color of the bucket, and we'll have the diamond market to our own.  Why worry about rockets, go for the easy money.  I am a trillionior in the making...

[PlainName]

spinning a bucket of graphite with a few slaps of iron on top

Unfortunately, you set it out here before applying for the patent, so someone could be rich from this but it won't be you

[DougSpindler]

Hard to believe they can get a mass spinning fast enough so it's traveling at 25,020 mph to a height of 200,000 feet.
...

Forget spinning it escape velocity.

For a 100meter diameter spinner to launch at earth escape velocity (25020mph or 11186m/s), the spinning centrifugal g-force would be a cool 255,360g.  According to wired.com, Spinlaunch is thinking 100kg payload.  That 100kg payload would have 25,536,000kg centrifugal g-force.

Why forget something that was never planned? Escape velocity has never been the goal. So everything you just said is meaningless as an argument.
...
...

Well, I did the math because Doug was talking about launching with escape velocity.  After I did the math, I looked at the numbers and I want to pitch that to the investors first, so I need everyone to forget about seeing my reply.

What I am going to pitch to investors will have nothing to do with launching, I will pitch something else instead:

Once I get a wheel going at mach 33, I have a g-force of 255,360g.  You must have already see spinning wheels, that is a simple concept.  I just have to make it go a bit faster.

You see, diamonds take just over 1000 centigrade at about 730,000 pounds per square inch pressure to form.  So, instead of launching anything, my wheel will be spinning a bucket of graphite with a few slaps of iron on top.  Takes a mere 3 pounds of iron for every square inch and I have 3*255,360g = 766,080 pounds per square inch.  We don't even have to worry about the 1000C, we'll let a bit of air in and let air friction do the heating and we have a bucket of diamonds just like that.  The whole concept is so simple, practically all I need to do is to choose the color of the bucket, and we'll have the diamond market to our own.  Why worry about rockets, go for the easy money.  I am a trillionior in the making...

Brilliant, I want to invest.  My VC firm, Dewey, Cheatham & How is willing to invest 1 Billion in the technology.   Will you help me pitch my other product?  You know how their are additives for gasoline which gives you car better gas millage, cleans the engine, and brightens teeth and curses all known diseases.  Well I have invented a revolutionary, miracle, product the car companies and the power companies don't want you to know about.  It an additive for battery electric vehicles.  Before charging your EV, if you plug this secretly developed device in you the charger port for just one minute it ill give your EV car better performance, charge the batteries faster, extend the range of your vehicle and keep the windows cleaner.  Think it will sell?

[Rick Law]

While my reply of "spinning a bucket of graphite with a few slaps of iron on top to make diamond" was clearly not serious, but it does serve the intend of showing the climate of the territory Spinlaunch is operating in.  Spinlauch is  targeting a mach 3 (2.3km/s) launch, that speed with their payload target put them in the diamond making territory.

Here is the math:

The Spinlauch site and many other sources say their payload capability is 200kg.

200kg = 440lbs.  At mach 3, that centrifugal acceleration g is 10,796g. The g-force on 440lbs totals 4,750,240 lbs.  If they mount the launch vehicle as shown in some of the illustrations, they are using some quick-release mounting brackets to attached the launch vehicle to the wheel.  If the contact area between the bracket and the wheel is 6.5 square inch, you have 730,806 lbs per square inch pressure the bracket exerts on the wheel.  That exceeded the diamond making 730,000 lb per square inch.

The problems they have to solve are not small ones.  Even if they are solvable using current material science, the solutions also must be practical and within their cost cap.  Their cost must be lower than the regular rocket launch cost or their solution is basically worthless.  They have a tall mountain to climb.

[PlainName]

Their cost must be lower than the regular rocket launch cost

Not sure that holds. If climate change gets figured in, for instance, it could be worth quite a bit of the price. Similarly, if it doesn't need the acres of safe space a rocket facility does then that can dent the price comparison.

[Nusa]

Quick release, yes. Everything else you said, even whether it's a bracket or some other solution, not so much. Applying math to your contrived scenario you already know doesn't work (a single bracket of 6.5 sq in) is just a waste of effort. Especially since you already mentioned brackets (plural!) in the sentence before that. Of course they'll make the collective surface area large enough for the mechanism to actually work! If they use that mechanism at all.

I don't know what the quick release solution is. If I had to guess, some sort of multiple carbon sling setup so the load itself doesn't need be reinforced to support brackets from the high side. Probably some sort of pin system for release. Or explosive bolts if pins won't work.

As for cost, that's not true at all during the R&D phase. Long term yes, unless the competition has more business than it can handle.

[DougSpindler]

Someone correct me if I'm wrong.  But I would think this would not work for the same reason we can't build a spinning space station to create artificial gravity.  With the knowledge/technology we have....  and we're not even close to figuring it out. 

[fourfathom]

Someone correct me if I'm wrong.  But I would think this would not work for the same reason we can't build a spinning space station to create artificial gravity.  With the knowledge/technology we have....  and we're not even close to figuring it out.

I'm honestly curious -- why can't we build a spinning space station?  I've assumed that we haven't so far because we don't need one, and we don't have the incentive to spend money on a station large enough to make this practical.  But is there really any reason, other than cost and desire, why we can't?  We're not talking about hundreds or thousands of G's here, but probably something like 1/2 G.  I think we have the knowledge and technology, or at least are close enough that figuring out the rest shouldn't be too difficult.

[DougSpindler]

Someone correct me if I'm wrong.  But I would think this would not work for the same reason we can't build a spinning space station to create artificial gravity.  With the knowledge/technology we have....  and we're not even close to figuring it out.

I'm honestly curious -- why can't we build a spinning space station?  I've assumed that we haven't so far because we don't need one, and we don't have the incentive to spend money on a station large enough to make this practical.  But is there really any reason, other than cost and desire, why we can't?  We're not talking about hundreds or thousands of G's here, but probably something like 1/2 G.  I think we have the knowledge and technology, or at least are close enough that figuring out the rest shouldn't be too difficult.

Here's a podcast which discusses why it hasn't been done.  https://www.nasa.gov/johnson/HWHAP/artificial-gravity
What I remember learning is we don't know of any material which would not fly apart due to the spinning or centrifugal force.  F=mw^2r  The deal breaker terms are the w^2 and r terms.  To build a stations with the material/technology we have would be so costly and use all of the aluminum we mine for 10 years it's just not practical.

Here's video explaining with an explanation.


Neil deGrasse Tyson has a podcast/YouTube channel StarTalk.  In one of the episodes he also explains why it's not practical.

[Nusa]

Someone correct me if I'm wrong.  But I would think this would not work for the same reason we can't build a spinning space station to create artificial gravity.  With the knowledge/technology we have....  and we're not even close to figuring it out.

I'm honestly curious -- why can't we build a spinning space station?  I've assumed that we haven't so far because we don't need one, and we don't have the incentive to spend money on a station large enough to make this practical.  But is there really any reason, other than cost and desire, why we can't?  We're not talking about hundreds or thousands of G's here, but probably something like 1/2 G.  I think we have the knowledge and technology, or at least are close enough that figuring out the rest shouldn't be too difficult.

Here's a podcast which discusses why it hasn't been done.  https://www.nasa.gov/johnson/HWHAP/artificial-gravity
What I remember learning is we don't know of any material which would not fly apart due to the spinning or centrifugal force.  F=mw^2r  The deal breaker terms are the w^2 and r terms.  To build a stations with the material/technology we have would be so costly and use all of the aluminum we mine for 10 years it's just not practical.

Here's video explaining with an explanation.


Neil deGrasse Tyson has a podcast/YouTube channel StarTalk.  In one of the episodes he also explains why it's not practical.

Are you even reading what you type? In the same paragraph you both say it's a) impossible with current materials and b) we can do it, but it costs too much. Those claims are mutually exclusive. In fact, neither of your links make the (a) claim, so I have no clue how you "learned" that. As for (b) so many problems with the claim, starting with using yesterday's launch costs, the false assumption that aluminum is only/best building material for space, and choosing to price a luxury mega-station instead of something more practical as a proof of concept re human biology. The kicker is even with all that, that podcast came to the conclusion that those costs were affordable for the clientele it was designed for.