Hello Rama,
i just had a game where we spammed about 40 EMP Launcher and destroyed 2nd HQ and a few support bases easily.
it cost 4k mass per launcher but how much per missile?
15k dmg per missile on buildings could be a bit overpowered if the mass cost is low.
1 EMP Missile = 15k Dmg (Dmg per Mass = ? / Build time?)
1 Nuke = 35k (cost about 15k = 2,33 Dmg per Mass and 5 or 6 min build time = 58,33 DPS on buildings)
Additionaly i think the range is too high. maybe reduce it to t3 arty range?