Re: SpinLaunch
Well as the launch vehicle breaks the membrane keeping the air out of the vacuum chamber the air will rush in to the chamber. This will create a turbulent force on the rotating arm which I assume has sufficient aerodynamic properties not to excessively oscillate and snap.
The electric motor could be used to slow the arm down as a brake but going from memory they were talking of several days to achieve full rotational velocity - so electrodynamic brakeing alone would presumably take the same time to slow it down - doubling the reuse time.
Of course if the rotor is as light as is feasible then since most of it is travelling relatively slowly then releasing a projectile massing 20 times the mass of the rotor arm would result in well in excess of 95% of the energy stored being released in that projectile leaving relatively little to be dispersed.
Biting the hand that feeds IT
