A technician replaces an ENIAC vacuum tube.
ENIAC programming chart representing the wiring necessary to set up an exterior ballistics equation.
Calculating the trajectory of artillery is extraordinarily challenging. Wind speed, humidity, temperature, muzzle velocity, air density, elevation, and even the temperature of the gunpowder must be taken into account in order to get an accurate reading. Ballistics tables that worked in rainy Germany were useless in Algeria where climate and elevation were so different. To make matters even more difficult, new weapons were constantly being adopted, which required new calculations. The Army desperately needed an expedient way to create reliable ballistics charts.