Spinlaunch... Can it succeed?

[coppice]

5.  They have built a centrifuge which achieves the expected g loadings.

Where did you get that? In the videos I've seen they only claim to have made something operating at a fraction of the stresses they need to achieve. They makes some solid claims about the potential strength of carbon fibre arms. They do some hand waving about what seems the biggest issue to me - the period of enormous imbalance they seem to have no way to mitigate.

[DougSpindler]

When it comes to spinning hard drives can we agree the drive manufactures played many tricks over the past 10-15 years?  My statement was drive manufactures who were claiming to have 15K/20k drives were really spinning them at half the speed 7200/10k and only using half the disk.

We can agree that many techniques have been tried over the years, but we do not agree that 15K drives were fake news. I suspect you've watched some conspiracy videos and are now repeating it. But if you want to cite sources to convince us otherwise, feel free. In any case, the niche market that expensive 15K drives served is now claimed by SSD drives with higher performance.

Hold on, I never said it was fake news, please, review my posts.  What I did say is the 15k drivers sold by some manufactures were spinning at 7200 RPM and NOT 15k.  The way they got the performance of a 15k drive was by using ONLY the outer tracks and altering altering the sector size.  The effective perforce of these drives was that of a 15k RPM drive and that's the way they marketed them.

You can verify my claim and these facts on the  Storage Networking Industry Association's 2015 and 2016 conferences, session presentations.  There next conference is in a few weeks.  Attend and you can verify first had with the drive manufactures.
https://www.snia.org/news-events/calendar

[DougSpindler]

5.  They have built a centrifuge which achieves the expected g loadings.

Where did you get that? In the videos I've seen they only claim to have made something operating at a fraction of the stresses they need to achieve. They makes some solid claims about the potential strength of carbon fibre arms. They do some hand waving about what seems the biggest issue to me - the period of enormous imbalance they seem to have no way to mitigate.

I believe in the video they claim to have reached those G forces on a smaller scale Spinlauch or   As a recall they were doggie about it saying they can't show it/talk about it as they way they are doing it is a trade secret.  That's the same bullshit line Elizabeth Holmes and Trevor Milton used.  And as we now know, Elizabeth Holmes and Trevor Milton were full of shit.  Spinlaunches claim sounds extraordinary.  And as Carl Sagan said, "Extraordinary claims need extraordinary evidence."  So far there's been no evidence to support their claim.
 

[PlainName]

You can verify my claim and these facts on the  Storage Networking Industry Association's 2015 and 2016 conferences, session presentations.  There next conference is in a few weeks.  Attend and you can verify first had with the drive manufactures.
https://www.snia.org/news-events/calendar

If that's what you consider to be citations then it's no wonder you've fallen for conspiracy theory-type claims.

[DougSpindler]

You can verify my claim and these facts on the  Storage Networking Industry Association's 2015 and 2016 conferences, session presentations.  There next conference is in a few weeks.  Attend and you can verify first had with the drive manufactures.
https://www.snia.org/news-events/calendar

If that's what you consider to be citations then it's no wonder you've fallen for conspiracy theory-type claims.

Dude I was at the conference both years when it was discussed. There no conspiracy BS as you suggest, its marketing.  Read the specs on the 15k dives and you WILL find the have capacity drive as in the ones which look like they should be 360 and really just 120.  You can easily verify by getting 15k drives off of eBay and measuring the RPM.

Plus, just think about it for a moment.  The drive market is highly competitive.  And 15k/20k drive cost a premium to produce.  So if the drive manufactures could get the performance of a 15k/20k drive at a cost of a 7200 drive don't you think they would do it?  Ockham's razor
 

[Nusa]

5.  They have built a centrifuge which achieves the expected g loadings.

Where did you get that? In the videos I've seen they only claim to have made something operating at a fraction of the stresses they need to achieve. They makes some solid claims about the potential strength of carbon fibre arms. They do some hand waving about what seems the biggest issue to me - the period of enormous imbalance they seem to have no way to mitigate.

I believe in the video they claim to have reached those G forces on a smaller scale Spinlauch or   As a recall they were doggie about it saying they can't show it/talk about it as they way they are doing it is a trade secret.  That's the same bullshit line Elizabeth Holmes and Trevor Milton used.  And as we now know, Elizabeth Holmes and Trevor Milton were full of shit.  Spinlaunches claim sounds extraordinary.  And as Carl Sagan said, "Extraordinary claims need extraordinary evidence."  So far there's been no evidence to support their claim.

One place would be from a video posted in this thread last month. Creating a centrifuge to spin objects up to 10000 G's purely for testing purposes is a pretty simple project by comparison. None of the hard stuff like release mechanisms, massive spans (shorter and faster works too!), and exit doors are required. Just making sure your load is balanced with weights or a second test cell, evacuating a small horizontal chamber, spinning it up and spinning it down again.

[DougSpindler]

I have a hard time believing hey are going to be able to get the exit doors to open and close fast enough at those speeds to allow projectile to pass, while holding a vacuum and NOT damaging the doors.  How large are these doors, one or two meters?  What's the time frame?  From fully closed to wide open back to fully closed in how much time?  1 msec?  Maybe less?   Just doesn't seem physically possible.

[Nusa]

You can verify my claim and these facts on the  Storage Networking Industry Association's 2015 and 2016 conferences, session presentations.  There next conference is in a few weeks.  Attend and you can verify first had with the drive manufactures.
https://www.snia.org/news-events/calendar

If that's what you consider to be citations then it's no wonder you've fallen for conspiracy theory-type claims.

Dude I was at the conference both years when it was discussed. There no conspiracy BS as you suggest, its marketing.  Read the specs on the 15k dives and you WILL find the have capacity drive as in the ones which look like they should be 360 and really just 120.  You can easily verify by getting 15k drives off of eBay and measuring the RPM.

Plus, just think about it for a moment.  The drive market is highly competitive.  And 15k/20k drive cost a premium to produce.  So if the drive manufactures could get the performance of a 15k/20k drive at a cost of a 7200 drive don't you think they would do it?  Ockham's razor

Make up your mind. Is it fake news or not? If you say any 15K drive on ebay will fail testing, then you are actually saying 15K drives are fake news. But the lack of any easily found citations 6-7 years after your conferences suggests that 15K drives are real news. Perhaps you heard someone discussing techniques to let slower drives compete in throughput, but probably not seek times.

In any case, it's the past. Occam's Razor says get an SSD drive instead now.

[DougSpindler]

You can verify my claim and these facts on the  Storage Networking Industry Association's 2015 and 2016 conferences, session presentations.  There next conference is in a few weeks.  Attend and you can verify first had with the drive manufactures.
https://www.snia.org/news-events/calendar

If that's what you consider to be citations then it's no wonder you've fallen for conspiracy theory-type claims.

Dude I was at the conference both years when it was discussed. There no conspiracy BS as you suggest, its marketing.  Read the specs on the 15k dives and you WILL find the have capacity drive as in the ones which look like they should be 360 and really just 120.  You can easily verify by getting 15k drives off of eBay and measuring the RPM.

Plus, just think about it for a moment.  The drive market is highly competitive.  And 15k/20k drive cost a premium to produce.  So if the drive manufactures could get the performance of a 15k/20k drive at a cost of a 7200 drive don't you think they would do it?  Ockham's razor

Make up your mind. Is it fake news or not? If you say any 15K drive on ebay will fail testing, then you are actually saying 15K drives are fake news. But the lack of any easily found citations 6-7 years after your conferences suggests that 15K drives are real news. Perhaps you heard someone discussing techniques to let slower drives compete in throughput, but probably not seek times.

In any case, it's the past. Occam's Razor says get an SSD drive instead now.

Dude get a grip - Did I ever say it was fake news?  Nope!  Never did.  What I said was what the the drive manufactures were a bit sneaky.  They were able to get the performance of a 15/20k rpm drive spinning the drive at half the speed.  Read what I just wrote several times so you comprehend it before posting a reply.

[Nusa]

I have a hard time believing hey are going to be able to get the exit doors to open and close fast enough at those speeds to allow projectile to pass, while holding a vacuum and NOT damaging the doors.  How large are these doors, one or two meters?  What's the time frame?  From fully closed to wide open back to fully closed in how much time?  1 msec?  Maybe less?   Just doesn't seem physically possible.

Only the last door has to be engineered to open quickly. The rest would be open already and be optimized to close as the projectile passes. Some of the doors would be closed before the last door even opens. 1 msec would be fast enough...how fast do you think air moves into a partial vacuum?

[coppice]

I have a hard time believing hey are going to be able to get the exit doors to open and close fast enough at those speeds to allow projectile to pass, while holding a vacuum and NOT damaging the doors.  How large are these doors, one or two meters?  What's the time frame?  From fully closed to wide open back to fully closed in how much time?  1 msec?  Maybe less?   Just doesn't seem physically possible.

Its not clear what they are doing. but its easy to see strategies that might work. For example, getting a door the size of the exit hole up to speed and closing it again in milliseconds seems crazy. Getting a panel 10 times as long up to speed so a hole in the panel passes the exit tube at the right moment seems a lot more achievable. From what I saw in a video it looked like they have some sort of shutter scheme like that.

[DougSpindler]

I have a hard time believing hey are going to be able to get the exit doors to open and close fast enough at those speeds to allow projectile to pass, while holding a vacuum and NOT damaging the doors.  How large are these doors, one or two meters?  What's the time frame?  From fully closed to wide open back to fully closed in how much time?  1 msec?  Maybe less?   Just doesn't seem physically possible.

Only the last door has to be engineered to open quickly. The rest would be open already and be optimized to close as the projectile passes. Some of the doors would be closed before the last door even opens. 1 msec would be fast enough...how fast do you think air moves into a partial vacuum?

I honestly don't know which is why I'm asking.  They show large doors.  In the video when they give a demo of the door closing it bounces.  Just doesn't seem possible and they don't want to talk about it or show us any more.  Right now it's a trade secret.  (Not sure what the secret is.)

[CatalinaWOW]

5.  They have built a centrifuge which achieves the expected g loadings.

Where did you get that? In the videos I've seen they only claim to have made something operating at a fraction of the stresses they need to achieve. They makes some solid claims about the potential strength of carbon fibre arms. They do some hand waving about what seems the biggest issue to me - the period of enormous imbalance they seem to have no way to mitigate.

I believe in the video they claim to have reached those G forces on a smaller scale Spinlauch or   As a recall they were doggie about it saying they can't show it/talk about it as they way they are doing it is a trade secret.  That's the same bullshit line Elizabeth Holmes and Trevor Milton used.  And as we now know, Elizabeth Holmes and Trevor Milton were full of shit.  Spinlaunches claim sounds extraordinary.  And as Carl Sagan said, "Extraordinary claims need extraordinary evidence."  So far there's been no evidence to support their claim.

They had a view of a centrifuge room.  It appears to be a centrifuge roughly two meters in diameter.  They asserted that they were running this at comparable loads to those used in the real application.

For cross checking numbers the acceleration is velocity squared divided by radius.  In the video they claim a Mach 5 launch velocity as I recall, which is roughly 1600 meters/sec.  My recollection is their target radius was about 40 meters.  This gives 64000 meters/sec*sec or about 6500 g.  So 10,000 g would be an appropriate design goal to give some safety margin.  Those with sufficient interest can go back and watch the video carefully and get exact numbers.

For the smaller scale centrifuge this requires rotating at a bit over 30,000 rpm for the predicted load, and 38,000 rpm for the design load.  Not trivial but doable.  Needs the carbon fiber and needs the vacuum, but on a far smaller scale.

Extraordinary claims do require extraordinary evidence.  But this particular claim is not particularly extraordinary and at least some evidence was provided, in the form of photos of test articles and verbal descriptions of test results.  For another example of the general feasibility of g hardening devices, think of the widely publicized application of bunker busting bombs in the Iraq wars.  The fuzing circuits in these had to withstand the impact of the bomb with several layers of reinforced concrete a meter or more thick.  Counting the impacts as they occurred.  And going off when the last layer as identified by the German designers of these bunkers.

You are free to dismiss any and all of that until SpinLaunch publishes full results in a peer reviewed document, which is the standard some set for evidence.  People with that standard would not accept a successful launch demonstration because it might have all been some kind of trickery.

I am willing to accept this part of the story because they are doing things others have done, and those doing the discussion of this issue demonstrated knowledge of the real issues in such efforts, and credible solutions to those issues.  It is certainly possible that they have missed something, and that updates to their designs will be required.  But nothing about the g hardening screams BS.  So this is just the normal engineering process, and the whole issue is whether they can do it (design, facilities and operational costs) cheaply enough to make the project economically viable.

Another example illustrates the difficulty of answering the economic question.  In the recent past two teams were issued contracts to develop a manned space capsule for use in ferrying astronauts to the ISS.  One team was new to the field, with limited experience in the area.  The other team had decades of experience.  One of those teams completed the task, more or less on schedule and budget.  The other is still not done, has blown past many schedules and reschedules and enormously outspent the other team.  The real world delivers many answers.  All seem somewhat obvious after the fact, and there will always be those who are there to tell you they knew it all along.

I remain skeptical on the financial side of this, but would not be flabbergasted if I am proved wrong.  I don't have any emotional investment in either the technical issues or the financial issues.

[DougSpindler]

You numbers are correct/close enough.  The diameter is 90 meters.
With the bunker buster bombs the Force is linear and not radial so while similar, I would think there would be enough of a difference it would not be the same.

I'm just saying it sounds very doubtful they will be able to spin the weight of 182 fully loaded Falcon 8 rockets in a 90 meter circle at 7.5 times per second, open a series of doors to launch one projectile, close the doors or keep them open for half a revolution and open and close the doors again.  At those Gs it's hard to believe all of the delicate components for the rocket and payload satellite would remain functional.  Maybe....  But you do have to admit it's hard to believe they'll get it figured out. 

[CatalinaWOW]

You numbers are correct/close enough.  The diameter is 90 meters.
With the bunker buster bombs the Force is linear and not radial so while similar, I would think there would be enough of a difference it would not be the same.

I'm just saying it sounds very doubtful they will be able to spin the weight of 182 fully loaded Falcon 8 rockets in a 90 meter circle at 7.5 times per second, open a series of doors to launch one projectile, close the doors or keep them open for half a revolution and open and close the doors again.  At those Gs it's hard to believe all of the delicate components for the rocket and payload satellite would remain functional.  Maybe....  But you do have to admit it's hard to believe they'll get it figured out.

When you use wrong numbers it is hard to get believable answers.  SpinLaunch's projectile mass is stated as 200 kg.  10,000 g makes that 2,000,000 kg equivalent.  Or about five Falcon 9 rockets (I couldn't quickly find data on Falcon .  It is still a big job, but 30+ times easier than you are making it.  For another comparison, SpaceX is planning to catch their 100,000 kg Starship Booster with their "chopsticks" mechanism.

From the point of view of g hardening radial and "linear" are only directions.  As long as you know ahead of time which one is being applied it doesn't matter much.  Of course if you have to design for multiple directions at once (or at least without changing hardware configuration) it is harder.   A couple of seconds of googling turns up the following paper.   

https://apps.dtic.mil/sti/pdfs/ADA435761.pdf

Excaliber is a delivered system so you may assume that the loads described can be survived.

Google is really useful when attempting to put real numbers on a problem.  Of course the internet is full of false information so you do have to think a little bit about the sources of your data. 

[DougSpindler]

You numbers are correct/close enough.  The diameter is 90 meters.
With the bunker buster bombs the Force is linear and not radial so while similar, I would think there would be enough of a difference it would not be the same.

I'm just saying it sounds very doubtful they will be able to spin the weight of 182 fully loaded Falcon 8 rockets in a 90 meter circle at 7.5 times per second, open a series of doors to launch one projectile, close the doors or keep them open for half a revolution and open and close the doors again.  At those Gs it's hard to believe all of the delicate components for the rocket and payload satellite would remain functional.  Maybe....  But you do have to admit it's hard to believe they'll get it figured out.

When you use wrong numbers it is hard to get believable answers.  SpinLaunch's projectile mass is stated as 200 kg.  10,000 g makes that 2,000,000 kg equivalent.  Or about five Falcon 9 rockets (I couldn't quickly find data on Falcon .  It is still a big job, but 30+ times easier than you are making it.  For another comparison, SpaceX is planning to catch their 100,000 kg Starship Booster with their "chopsticks" mechanism.

From the point of view of g hardening radial and "linear" are only directions.  As long as you know ahead of time which one is being applied it doesn't matter much.  Of course if you have to design for multiple directions at once (or at least without changing hardware configuration) it is harder.   A couple of seconds of googling turns up the following paper.   

https://apps.dtic.mil/sti/pdfs/ADA435761.pdf

Excaliber is a delivered system so you may assume that the loads described can be survived.

Google is really useful when attempting to put real numbers on a problem.  Of course the internet is full of false information so you do have to think a little bit about the sources of your data.

The 182 fully loaded Falcon rocket number is from the video.  Not my calculation.

[Rick Law]

...
Spinlaunch is saying they will be launching 10 ton projectiles.
For Spinlaunch to work they will have to create the single strongest tensile strength structure on earth.
They goal is to launch a 10 ton projectile by spinning it at 7.5 time per second at a diameter of 90 meters resulting in force 10,000 times it's weight. That would be 10 tons times 10,000 or 100,000 tons.  That would be the weith of 182 fully loaded Falcon 8 rockets.

Instead of a counterweight, their plan is to launch a equal weight second satellite in half a turn.  Not sure how the doors at that speed are going to be able to open and close that quickly.

I think the video is a bit misleading when they said the physics checks out and say they have proprietary technology.  Isn't that similar to the line Elizabeth Holmes would repeat over and over? 

In the end, it's all going to comedown to will the money run out before they solve the technical issues.
...
...

(Bold added to quote)

"...They goal is to launch a 10 ton projectile...Instead of a counterweight, their plan is to launch a equal weight second satellite in half a turn...."

If they indeed said that, the smell of crap just filled the room.  Forget the doors, a bigger problem is at-hand.

10 ton at 10,000g is 100,000 ton g-force.  So they launch one (immediately losing the wheel/arm balance) and wait 1/2 a turn to launch the second payload projectile that was the counter weight during spin-up.

At 450 RPM, that is 7.5 Rounds per second.  So 1/2 a turn takes about 1/4 second.  The spinning arm will have 100,000 tons pulling against the spinner axis for 1/4 second.  They must be developing some hyper-super ball bearing to handle that kind of force on the spinner axle yet it will be able to be control to sub-millisecond for precision release.  How many launches before the whole spinning assembly torn itself part?

This doesn't pass the smell test.

[PlainName]

They must be developing some hyper-super ball bearing to handle that kind of force on the spinner axle

I think the oscillation will be as big a problem.

OTOH, what if they use a big bearing. Like several feet (sorry, a metre or two) in diameter? More likely to be a roller (or taper roller) than ball bearing too.

[DougSpindler]

I’m just repeating the innovation or crap that’s in the video.  They claim the bearing can withstand the forces for half a revolution.  No mention of how the doors are going to be able to open/close/open/close in half a second.  I still think money is going to be the limiting factor with Spinlaunch.   

[Nusa]

I’m just repeating the innovation or crap that’s in the video.  They claim the bearing can withstand the forces for half a revolution.  No mention of how the doors are going to be able to open/close/open/close in half a second.  I still think money is going to be the limiting factor with Spinlaunch.

You're up from 1 ms to 500 ms. I think you'll find that 500 ms doors are quite easy to manage with conventional technology.

And yes, it's going to be about money. Stop trying to use different aspects of technology you don't claim any expertise in as your main arguments.

[Rick Law]

They must be developing some hyper-super ball bearing to handle that kind of force on the spinner axle

I think the oscillation will be as big a problem.

OTOH, what if they use a big bearing. Like several feet (sorry, a metre or two) in diameter? More likely to be a roller (or taper roller) than ball bearing too.

They can use whatever they want.  Personally, I think they are better off doing some kind of energy recapture.   But as Dave already pointed out in the quote (below), they will run out of money.  That is of course they got some government intervention.  Government is basically an infinite source - until they too run out of other people's money.

In the end, it's all going to comedown to will the money run out before they solve the technical issues.

My almost zero mechanical knowledge money is on them encountering so many issues that no amount of money will save it.

[DougSpindler]

I’m just a spectator offering my commentary and opinions.  If it were easy, someone would have done it already.  If it’s too difficult, they will run out of money.  The race is on.

[SiliconWizard]

The question though is, will they just run out of money and stop, or will they end up in a trial? Bets are open.

[PlainName]

You mean a trial run or a criminal trial?

[onsenwombat]

They must be developing some hyper-super ball bearing to handle that kind of force on the spinner axle

I think the oscillation will be as big a problem.

OTOH, what if they use a big bearing. Like several feet (sorry, a metre or two) in diameter? More likely to be a roller (or taper roller) than ball bearing too.

Or maybe they will exploit the flux jet hyperloop plasma whatever technology and create a revolutionary bearing that nullifies any and all force applied?