This is another overly long video that is filled with a massive amount of science in all sorts of disciplines: physics, material science, chemistry, engineering, mechanics.
The video sees the Real Engineering host, Brian McManus, visit SpinLaunch's centrifuge being built to launch satellites into space primarily via kinetic energy rather than through rocket fuel combustion...which sounds totally bonkers but might work out.
One of the main technologies here involves a carbon fiber-reinforced polymer tether. At 3:00 that concept is explored with a laminated carbon fiber reinforcement mock-up of the thickness that they need the tether to be to hold the millions of pounds of force that would be necessary.
Then - 8:00 - they look at the need to spin up that tether in a vacuum chamber so that it doesn't melt the carbon fiber from the friction due to air resistance. They also describe how truly low pressure vacuum chamber pumps work and why the SpinLaunch people don't need a vacuum chamber with quite that low a pressure. The idea of outgassing from the metallic parts - 10:25 - was amazing to me. It makes sense to me that there would be small amounts of oxygen gas 'dissolved' in any steel parts, but I had certainly never thought about it before. It's an equilibrium problem, I guess, as oxygen is removed from the atmosphere around the part.
At 16:20 they take a look at the challenges of opening a low pressure chamber at near vacuum to the atmospheric pressure outside without destroying the chamber inside when the air rushes in. They've used a pairing of mylar layers that are broken through and two incredibly quick closing doors.
From 21:30 they explain how they address and minimize vibrations - especially once the payload is let go, leaving a highly unbalanced weight on the arm.
The next section - from 26:45 - they look into the ballistic coefficient of the projectile and why a heavier vehicle might be better for their launch process - something that is very well against the traditional method of launch's goals. With rockets, lighter is better. With the SpinLaunch, heavier and denser is somewhat better because it allows the projectile to gain more momentum without corresponding drag and heating due to friction with the lower atmosphere.
The whole process is fascinating, and I'm hopeful that it turns out to be feasible because I would love to see a full scale SpinLaunch facility built and functioning - for the science and novelty if for nothing else.
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