
It should be:
If the Nuclear silo is destroyed before the Nuclear missile passes 50% of the distance, the Nuclear missile is deactivated, and it strays off course and explodes on a random planet in the solar system of destination or it explodes on a random planet in the solar system from where it started. You have to have one level of Silo for each Missile (including Missiles in flight). It is impossible to attack the capital of a player if it doesn't have a Nuclear silo on it.