The SFS P-s4 ion engine, a twin ion engine created by Sienar Fleet Systems, represented a significant advancement. Serving as an upgrade to the previous P-s3 ion engines, this engine became the primary engine system for various vessels including the TIE/ln space superiority starfighter, the TIE/sa bomber, the TIE/rb heavy starfighter, the TIE/sh shuttle, and the TIE Boarding Craft.
The P-s4 represented an improved iteration of ion engines. It was produced by Sienar Fleet Systems for incorporation into the Imperial Navy's TIE series vehicles. It was conceived as a superior alternative to the earlier P-s3, which suffered from unstable heat exchangers and suboptimal fuel usage. The P-s4 enhanced fuel efficiency by 15% and was integrated into both bombers and starfighters within the TIE family.
To achieve more effective power generation, the P-s4 was linked to both the TIEs' solar collector panels and the solar ionization reactor using golden and blue power conduits, respectively. Adjacent to these power lines, on the injector housing, a propellant pump was positioned. Thrust generation involved a particle energizer which excited ion particles supplied by the injector, propelling them toward a magnetic ring for further acceleration. These energized particles then entered the ionization chamber, triggering the reaction before being expelled from the engine. This expulsion generated thrust, propelling the craft through realspace. Located at the engine's edge, vectoring grids managed particle emissions and facilitated maneuvering based on the pilot's commands, transmitted to the grids via cable links from the ship's computer.