Pre-Contact warships used rockets and projectiles to breach enemy armor and render them vulnerable to laser barrages. Rockets were slow to accelerate but had impressive ranges of engagement when built with multiple stages. Unfortunately, the longer the flight time the more time enemy point defense had to pinpoint their exact location. A large enough rocket barrage could overload the defenses and shatter armor, but those were very expensive and not commonly performed. We were never officially at war with anyone until the Shang attacked us after all. There may have been some disagreements over colonial possessions, but it was generally considered bad form to open fire over mere disagreements.