The invention of the rocket has sometimes had negative effects on human society. For example, these devices have been used in warfare. people have sometimes been killed en masse. Rocket technology has improved with time, rocket engines have come to possess greater range. Conceivably, deadly "warheads" can be sent to reach targets far away from the launch site. Recently, the development of nuclear power, a rocket with a nuclear warhead can be the the deaths of millions of people in a few moments. Tens of millions more can possibly die the spread of radioactive fallout from a single explosion.