Any time that I beam down to any base to battle any enemy there is SEVERE lag and the game crashes.
This is a serious problem since about half of the missions are on a base or on ground. This issue needs to be resolved.

It's not a perfect fix - but try disabling dynamic lighting in the advanced video options. See if that at least makes the game playable for now.

I have tried that and I even lowered the graphics and the game still crashes whenever i play a ground mission where there is phaser fire