Hoersch-Kessel Ion Drive
this popular sublight drive uses a power source to generate ions, which are expelled through an exhaust nacelle to create thrust. It uses almost any material as a power source. Although it works best with heavy metals, the H-K Ion Drive can use cryogenic cells, liquid reactants, and ion pods as power sources. The fuel is first broken down into nuclear energy and converted to ions. These ions are then expelled from the ship, which causes the ship to move in the direction opposite the thrust. Given that the H-K Ion Drive creates radioactive nuclear energy, any ship that is equipped with one must require towing or the addition of a repulsorlift to travel within a planet's atmosphere. Their use is extremely widespread, and they are low-maintenance drives.