Hammerfest
Oh yeah, i remember that mission. The first part of the mission is annoying because you have to manoeuvre through icy glaciers in an attempt to find the base, which is at the top left of the map.
You'll encounter an Obelisk of Light on your way there, so make sure you find and destroy the powerplants first to kill the powersupply. You'll have to destory the side of the glacier to get to the powerplants. Their hard to find so use the cursor to identify them.
Once you've located the base, capture everything you can and build up a massive force of Titan's and Wolverines to attack the Nod base located to the south of your base.