It is difficult. Our strategy for nightfall was: 2 by the Warsat with void shotguns and void MG 1 hanging back with void sniper or ideally telesto The one hanging back drops the turrets on each drop ship as it comes in. Two full telesto hits does it. When that's done throw grenades, heavy, telesto into the melee around the Warsat. The two by Warsat just use cover and shotgun everything. When the second drop ship comes in the one on turret duty needs to rotate to new cover or you'll get smashed. If you can, pop a Titan bubble over the Warsat (blessing of light) at about 70-75%. I confess I did it with one regular playing partner and one random. The first random kept dieing before 25% and left after two tries. Second random joined and we did it first time. For weekly and normal strikes, you don't need the turret duty. Just use cover. You only need one by Warsat at a time. 3 is no quicker than 1. Hope you get it done!