Chrono String Engines were the source of power for spacecraft. These engines drew their power from Chrono Strings. Since the probability of gaining energy from any single Chrono String is very low, most engines simply gathered large amounts of them in order to be able to extract some energy from a few of them. This was effective enough to provide a continuous and stable power source, but only up to a certain point. There were specialized engines that allowed greater power output through usage of the H.A.L.O. System, which was only equipped on the Emblem Frames. Depending on how well an Angel could handle the H.A.L.O. System, it would have been possible for the engine to output nearly limitless amounts of power.