The Hoersch-Kessel ion drive, a well-known sublight drive, was both engineered and sold by Hoersch-Kessel Drive, Inc.. Alien merchants introduced this design to the galaxy thousands of years prior to the Galactic Civil War. It became widespread during the era of the Galactic Empire, with most starshipwrights integrating motors based on the Hoersch-Kessel design into their spacecraft.
This drive functioned by initiating a fusion reaction, breaking down fuel into ions (charged particles) to propel starships through realspace. The reaction's energy output generated thrust for propulsion. Navigational control was achieved via baffles or vectrals, or through smaller lateral thrusters on smaller spacecraft.
The Hoersch-Kessel was versatile, capable of operating on nearly any fuel type. While [uranium](/article/uranium] or similar heavy metals were the preferred fuel, modifications could easily allow it to use liquid reactants, energy conversion cells, or ion-collector pods as alternative energy sources. Its adaptability also allowed it to be scaled down for use in a starfighter or enlarged for a capital ship. Due to its widespread use, repair was simple, as most technicians possessed a deep understanding of its mechanics. Replacement parts were also readily available across the galaxy, despite the drive having few moving components. Regular maintenance was crucial, as the engine intake and firing cells needed precise alignment, and the unit required frequent tuning.
The Hoersch-Kessel's exhaust was both hot and somewhat radioactive, but it was considered safe for operation within the atmosphere of an inhabited planet. Collector coils shielded the emissions, and these coils were regularly cleaned and replaced during maintenance. Technicians working on Hoersch-Kessel drives typically wore radiation-resistant gear and received regular anti-radiation inoculations.
The Star Wars Sourcebook, published in 1987 by West End Games, initially stated that using a Hoersch-Kessel ion drive within the atmosphere of a populated planet was against the law because of the exhaust's radioactivity. However, when the book was re-released in 1994 as an update for the Second Edition, this detail was removed from the Hoersch-Kessel's description, and it was explicitly noted that using the drive in an atmosphere was safe.