Very difficult question, also because there is a difference in the original (italian) rules of the game and the edition printed by FFG.
In the Italian rules the strength of this card (that is the number of dice you roll)depends on the number of production centres the player controls. Any production centre = 1 die. The Italian rules also specify that the missiles must be uses only on enemy land areas, while the english rules (both Epic and Premium) allow the use also againsta sea areas (that means against submarines).
Being the designer of the game, I can say that, in the spirit of the original rules, missiles couldn't be used against your own troops.