Space startup wants to sling satellites into orbit with a huge centrifuge
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captaincranky
Posts: 19,684 +8,824
But, but, but, they won't be able to do it without your "help" Dust that wallet off....
Proving once again that no "good idea" goes unexploited:
defaultluser
Posts: 527 +397
Think positive, man!
https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.101.9472&rep=rep1&type=pdf
Granted those are shock pulses rather than sustained acceleration, but high-G ruggedization is not something that needs to be started from scratch for this.
I know you are hopeful, but there are better ways than SpinLainch
Space gun has always been a more viable approach (because the instantaneous acceleration can be averaged over the length of that huge barrel), while these things need to endure it during however long it takes to finish swinging (they say about an hour for the final orbital spinner)!
The downside to this: , once they get that big, you're only a State Sponsor away from building a Baby Babylon (and being able to drop orbital bombs nearly anywhere).
https://www.bbc.com/future/article/20160317-the-man-who-tried-to-make-a-supergun-for-saddam-hussein
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Avro Arrow
Posts: 3,721 +4,821
Well, sure, but we're not talking about a mobile rail gun application here. We're talking about a stationary launch system for spacecraft. For all we know, it'll have its own dedicated generating station (hopefully hydroelectric but nuclear would work too).
wiyosaya
Posts: 9,760 +9,644
The question is just how big does it need to be in order to overcome all the forces acting against it such as atmospheric drag - as @captaincranky and does the required size then make it impractical?
Under the sqrt, it seems to be a directly proportional relationship which, to me, could imply that it may need to be quite big.
defaultluser
Posts: 527 +397
Their sales pitch said Football field sized.
I guess the question they have to answer is: is this massive thing easier to build than an extremely long gun barrel (already been working for several years)?
The pitch to improve the pressure wave from the explosive:
The Starfire Space Cannon
Low Cost access to space with the Starfire space cannon
The Space Gun has already had a long history that could be harnessed (so why start from the beginning here with Spin?).
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mgwerner
Posts: 242 +393
I'll raise that little example with Gerald Bull's Space Gun:Their sales pitch said Football field sized.
I guess the question they have to answer is: is this massive thing easier to build than an extremely long gun barrel (already been working for several years)?
The pitch to improve the pressure wave from the explosive:
The Starfire Space Cannon
Low Cost access to space with the Starfire space cannonwww.kickstarter.com
The Space Gun has already had a long history that could be harnessed (so why start from the beginning here with Spin?).
https://nuke.fas.org/guide/iraq/other/supergun.htm
captaincranky
Posts: 19,684 +8,824
Here's a Quora page about whether or not the SR-71 needed leading edge deicers.
I really wish whomever's idea this is, would explain how are you going to control heating in an object spinning in air for an hour bringing it up to orbital velocity, without burning it to a cinder.
captaincranky
Posts: 19,684 +8,824
Sending objects into space doesn’t always have to be an expensive and complex task conducted exclusively by filthy rich entrepreneurs or governments. Sometimes all you need is a determined Canadian engineer, a backyard, and a Kickstarter campaign — at least that’s what Richard Graf is hoping.
And so, the begging for money begins.
captaincranky
Posts: 19,684 +8,824
I suggested that in an earlier post. Perhaps I missed it in the article?
cliffordcooley
Posts: 13,141 +6,441
captaincranky
Posts: 19,684 +8,824
Well, I'm about as skeptical as skeptical can be about this.
That said, I'm wondering about the time factor of contact with the atmosphere would aggravate or mitigate the heating.
Next, assuming this mess is spun up in a vacuum, the instant the "cork is pulled", it should have an effect similar to a supercharger with the inrush of air.. That in itself would cause a significant deceleration.
As far as the heat goes, I wonder if some ablative covering could be employed to keep the core cool.
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For a very small subset of the game scenarios.
BuckarooBonzaii
Posts: 456 +323
kiwigraeme
Posts: 1,995 +1,405
I'm sceptical as well - is not zero carbon - unless from renewable energy
No ones talked about the device itself - I have visions of shattering CDs.
20% of accerators power is undefined - do they mean spinning at 20% full speed.
or more correctly 20% electricity
Big deal - momentum = 1/2 *m*V^2 - the material stress, the tolerances etc - are they going to magnetic levitation- pressure on ball bearings etc etc .
That prototype looks cheap -what a small concrete pad to anchor it - can't see depth , no safety features visible .
Then there's the electronics - spinning at a speed to get at least sub-orbital - someone here can calculate the timing needed - all we know is 2235 metres/second and 98 000 000 m/s^2- so from that we can calculate the radius .
Anyway lets assume diameter of 50m - so times pi your circumference is roughly 157m =so 14.2 revolutions per sec.
So lets say just need 1 degree accuracy - It's past me bedtime would that be 1 second /(360*14.2)
So your release needs to be real precise . Saying that I think it could be done with a magnetic binding posts , and laser lights on spinner - when light hits say 93 degrees , electricity turned off to binding posts - so could be fine tuned . Still think it will be hard.
Plus release points should be on a mountains 3 or 4k high at least - it's a small projectile - no fuel to be carted in etc .
Plus pumpkin chuckers break the pumpkin it thrown too fast
No ones talked about the device itself - I have visions of shattering CDs.
20% of accerators power is undefined - do they mean spinning at 20% full speed.
or more correctly 20% electricity
Big deal - momentum = 1/2 *m*V^2 - the material stress, the tolerances etc - are they going to magnetic levitation- pressure on ball bearings etc etc .
That prototype looks cheap -what a small concrete pad to anchor it - can't see depth , no safety features visible .
Then there's the electronics - spinning at a speed to get at least sub-orbital - someone here can calculate the timing needed - all we know is 2235 metres/second and 98 000 000 m/s^2- so from that we can calculate the radius .
Anyway lets assume diameter of 50m - so times pi your circumference is roughly 157m =so 14.2 revolutions per sec.
So lets say just need 1 degree accuracy - It's past me bedtime would that be 1 second /(360*14.2)
So your release needs to be real precise . Saying that I think it could be done with a magnetic binding posts , and laser lights on spinner - when light hits say 93 degrees , electricity turned off to binding posts - so could be fine tuned . Still think it will be hard.
Plus release points should be on a mountains 3 or 4k high at least - it's a small projectile - no fuel to be carted in etc .
Plus pumpkin chuckers break the pumpkin it thrown too fast
captaincranky
Posts: 19,684 +8,824
@kiwigraeme Kudos on the math. I forget algebra the minute I close the textbook and walk out of the class
What I manged to get out of it, is the fact that if you double the diameter, you half the rotational speed..`That said, you need a diameter of 800 meters, to have the rotational speed be a "realistic" 2 revolutions per second.
Any of that notwithstanding, if you hit.atmospheric pressure at 18,000 Mph, (remember, we're spinning this up in a vacuum),. you might as well be slamming into a brick wall..
If you gradually decrease the vacuum to sea level pressure, the issue of heat rears its ugly head once again. (Keep in mind the windscreen of the SR-71 was made of Pyrex, and it flew above 90% of the earth's atmosphere).
So, what do we do next, super cool the incoming air with liquid nitrogen?
What I manged to get out of it, is the fact that if you double the diameter, you half the rotational speed..`That said, you need a diameter of 800 meters, to have the rotational speed be a "realistic" 2 revolutions per second.
Any of that notwithstanding, if you hit.atmospheric pressure at 18,000 Mph, (remember, we're spinning this up in a vacuum),. you might as well be slamming into a brick wall..
If you gradually decrease the vacuum to sea level pressure, the issue of heat rears its ugly head once again. (Keep in mind the windscreen of the SR-71 was made of Pyrex, and it flew above 90% of the earth's atmosphere).
So, what do we do next, super cool the incoming air with liquid nitrogen?
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captaincranky
Posts: 19,684 +8,824
See my post directly above. (#45)
captaincranky
Posts: 19,684 +8,824
If Jules Verne doesn't mind me asking, how was he planning on getting back?
kiwigraeme
Posts: 1,995 +1,405
So just a souped up battery powered nerf gun!
Another reason for doubt is - why hasn't the military used this for launching depleted uranium or whatever they use .
Cannonball enters near the centre - accelerates as follows a spiral coil outwards - to go in the direction of the "barrel"
Those Russian Katyusha rocket launchers look cool - but something launching a 10kg metal ball every every second endlessly at say 2000km/h - would pulverise everything in front of it
Another reason for doubt is - why hasn't the military used this for launching depleted uranium or whatever they use .
Cannonball enters near the centre - accelerates as follows a spiral coil outwards - to go in the direction of the "barrel"
Those Russian Katyusha rocket launchers look cool - but something launching a 10kg metal ball every every second endlessly at say 2000km/h - would pulverise everything in front of it
Avro Arrow
Posts: 3,721 +4,821
That's a very good point you make. Personally, I think that all of these ideas, while having merit, cannot replace the ultimate idea of a space elevator. Space elevators will ultimately be how we travel to space because they'll be cheap, clean and gentle to use:
Avro Arrow
Posts: 3,721 +4,821
I'm not sure that he was. At the time, we didn't know that space was an airless vacuum with zero pressure. We didn't realise just how hostile to human life it is.If Jules Verne doesn't mind me asking, how was he planning on getting back?
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