Comments by "" (@charlesvan13) on "SpinLaunch: A Rocket Startup That Wants to Catapult Satellites Into Space | WSJ" video.

@brianethridge208 You'd still have the problem with spinning. But there is no atmosphere on the moon so you wouldn't have the problem with high speed in the dense sea level atmosphere. Supersonic planes can only go much over mach 1 at high altitude where the air is thinner.
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There are several reasons why it wont work. They're planning to build a 100m radius centrifuge, rotated at 450 rpm to achieve mach 5. But the projectile will be under 10,000 g of acceleration. A very small rocket, say 1000 kg, would be under 10 million Kg of force. That's more than the liftoff thrust of the Saturn V. The centrifuge will fly apart. It also wont send the rocket straight. When released it will be rotating at 450 rpm. It will be tumbling end over end. Mach 5 tumbling, in the dense lower atmosphere, will cause the rocket to fly apart.
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@DataGeek903 The whole apparatus will explode. One basic observation that they've seemed to have ignored is that when released the rocket will be tumbling at the rotation of the centrifuge. It will be spinning at 450 rpm, and it wont just stop spinning. What's going to happen, is they wont be able to build a centrifuge that can hold together at 10,000 g. But even if they could, the rocket would disintegrate. Planes can only go a little over mach 1 at sea level. The high speed mach >2 planes fly that fast at high altitude. The rocket will explode.
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