[AlexanderHowl]

A reasonable protection against a high velocity attack would be to have stripped down large spacecraft to act as interceptors. A SM+8 spacecraft could have a control room, a fission reactor, a fuel tank for coolant, a reactionless engine, and sixteen ice armor. It would be capable of intercepting high velocity targets through getting in the way of their ballistic paths, either destroying them through impacts or forcing them to redirect and miss their target. The advantage of the ice armor is that it vaporizes during an impact and, while vaporizing, efficiently transfers heat to the solid parts of both spacecraft, greatly reducing any resulting high velocity debris by vaporizing the vast majority of the solid parts.

You could even have a SM+10 towing truck that positions SM+10 pieces of ice in the path of high velocity ballistic attacks (a SM+10 spaceship with eighteen ice armor and two core cargo holds full of ice). It would have a control room, a habitat, a hanger bay, two fusion reactors, three armor, three external clamps, four fuel tanks for coolant, and four reactionless engines. It could tow three SM+10 pieces of ice into position. Even an SM+14 spacecraft would be utterly destroyed if it hit a SM+10 piece of ice at 0.01c (something like 5 million dice of d-damage).