the first electronic ballistic chronograph was invented by kiryako ("jerry") arvanetakis in the 1950s. as consulting engineer under contract by naca (later nasa), he was asked to find a way to accurately measure the velocity of various projectiles fired at hyper-velocities into a variety of engineered materials in anticipation of manned space flight. his first design was an open rectangular frame of square aluminum tubing with a screen of fine copper wire at both ends. breaking the first wire started charging a capacitor, breaking the second wire stopped it. measuring the accumulated voltage and knowing the rate of charge the elapsed time could be accurately calculated.