The Space Catapult That Could Topple SpaceX

[Elderberry]

Medium by Will Lockett 11/19/2021

Musk should be worried about Spinlaunch’s upcoming launch vehicle

Right now, SpaceX is the undisputed king of space. Their rockets can carry more for less and soon could even take us to Mars. Musk looks set to have yet another monopoly on his hands. But Spinlaunch has come up with a novel launch system that propels crafts into space, significantly undercut SpaceX in price and use carbon-neutral fuel! Their solution? A giant catapult the size of the Statue of Liberty. No, seriously, it sounds insane, but this technology could dethrone SpaceX.

So how does a giant space catapult (also known as a kinetic launcher) work? Well, it is a combination of a vacuum chamber, high-speed centrifuge and high-speed airlocks.

Firstly, the projectile which contains the payload is attached to the end of the giant centrifuge, with arms just shy of 150ft long. This centrifuge is within a massive vacuum chamber. This reduces air friction allowing the centrifuge to hit mind-bending speeds. The centrifuge spins up until the projectile is travelling at around 5,000 mph! Then, with precise timing, the projectile is released and travels down the exit tube. A high-speed airlock at the end of the exit tube allows the projectile to exit without compromising the vacuum chamber. The projectile then leaves the launcher with enough kinetic energy to send it all the way up into space, where the satellite payload can be released.

More: https://medium.com/predict/the-space-catapult-that-could-topple-spacex-fe0d51411bb6


                                                  Spinlaunch 1/3 prototype

[Smokin Joe]

I wonder if this is really a cause for worry?

After all, other ideas have been tried...

https://en.wikipedia.org/wiki/Project_HARP

[Kamaji]

Question:  what happens when this projectile, which has been spun up to 5,000 mph in a vacuum chamber, hits the ambient outside air?

[Joe Wooten]

Question:  what happens when this projectile, which has been spun up to 5,000 mph in a vacuum chamber, hits the ambient outside air?

It gets really hot really fast......

This spinner will not be able to put a useful payload into orbit without a rocket assist. At best, it will replace the first stage. If it were to come mout of the spinner at orbital speed, it would almost instantly become an incandescnet ball of plasma from frictional heating and would lose enough velocity to not be able to make it into orbit, so the speed upon leaving the spinner will have to be at least 20% to 25% greater than orbital speed which makes the friction problem a lot worse.

Given the weight of a good thermal protection scheme, I'd say about 5000 mph out the spinner is about right for replacing a first stage. Also, given the size of a manned vehicle or a typical comsat, it will be good for small sat launches, but not much else.

[Joe Wooten]

https://www.americanthinker.com/blog/2021/12/how_much_money_can_you_make_promising_to_get_satellites_into_orbit_with_a_slingshot.html

[Kamaji]

It gets really hot really fast......

This spinner will not be able to put a useful payload into orbit without a rocket assist. At best, it will replace the first stage. If it were to come mout of the spinner at orbital speed, it would almost instantly become an incandescnet ball of plasma from frictional heating and would lose enough velocity to not be able to make it into orbit, so the speed upon leaving the spinner will have to be at least 20% to 25% greater than orbital speed which makes the friction problem a lot worse.

Given the weight of a good thermal protection scheme, I'd say about 5000 mph out the spinner is about right for replacing a first stage. Also, given the size of a manned vehicle or a typical comsat, it will be good for small sat launches, but not much else.

Possibly explosively hot?  At what point would the interface between the internal vacuum and the outside air become, in effect, like a hard surface?  I realize that a comparison to hitting water is not completely appropriate because the atmosphere is compressible and water is not; however, it just seems to me that this would result in a potentially catastrophic result.

[Joe Wooten]

Possibly explosively hot?  At what point would the interface between the internal vacuum and the outside air become, in effect, like a hard surface?  I realize that a comparison to hitting water is not completely appropriate because the atmosphere is compressible and water is not; however, it just seems to me that this would result in a potentially catastrophic result.

Agreed! It would be an explosion of an instant plasma. The rocket stage would also explode.