If you guessed 50kg, you are thinking of an electric vehicle. The answer is a staggering **417 kg (920 lbs)**. The term "Rare Earth" implies a sprinkle of magic dust, but it is actually a massive structural dependency. If the supply chain tightens—as signaled by new export controls this week—the US Air Force doesn't just lose "chips"; it loses the literal actuators that move the plane's rudders.