I'm having trouble getting the final goal of eliminating the Mars Space Port defenses, can anyone give me some advice or an easy way to get passed this? In terms of units, I have most of my vehicles;

4 Apollos, 4 Deimos, 4 Phobos, and that junk car you get at the beginning. Is it anywhere near enough or do I need to restart? I've spent more than I should on this mission and it's starting to get to me.