If you wear red armor and use an envirosuit right before the fight you can get a high enough resistance to his rocket attacks so that you can just tank him.
Even better, make it a fireproof red armor, the basic assembly that anyone can create. Those 55% fire resistance will cut his attacks down to size, and combined with envirosuit, it's 80%. With this combination, most of the rockets will hit you for exactly 1 HP.