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kleinbl00  ·  1760 days ago  ·  link  ·    ·  parent  ·  post: Inside SpinLaunch, the Space Industry’s Best Kept Secret

You know, just for fun.

Moment of inertia is

(mass1)(mass2)/(mass1 plus mass2)(distance)^2 is (1600)(1600)/3200 times (37m)^2 is 1.1e6 kg m^2 (presuming our 120 feet of kevlar has no mass).

kinetic energy is 1/2 I omega^2 is (0.5)(1.1e6)(74 rad/sec)^2 is 3.01 gigajoules.

Presume it's perfect. Presume it's frictionless. Presume sunshine and rainbows. You just pumped 833 kW/h into this thing and you're letting it go in a millisecond. That's 1400lbs of TNT, which is troublesome, because the linear energy is 1200lbs of TNT, which means ThurberMingus' entirely-expected flat spin has some real power behind it.