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The sound produced by ion thrusters

The Ion Engine is a low-thrust; extremely high-efficiency engine. It ties with the RCS Thrusters as the smallest-footprint engine in SFS, at the size of 2×1 units. Another similarity to the RCS Thrusters is that it does not have to be connected to a fuel tank directly; instead it always drains all fuel tanks equally.

Exhaust of ions from the ion thruster

Due to its extremely low thrust, it does not function well in atmospheres. However, its high efficiency allows it to constantly operate over long periods of time, useful in long journeys, and the low thrust is useful in dockings, and other precise maneuvers in lieu of RCS thrusters.

The engine is commonly used on space probes and satellites for correcting trajectories. Its high efficiency makes it a really useful engine for those type of spacecrafts.

This engine was added to Spaceflight Simulator in version 1.35.


  • The thrust of the Ion Engine in the game (20 kN) is in kilonewtons, which is much higher than real ion engines, which exert forces of millinewtons (mN).
  • In the game, it will take 60 minutes for an ion engine to fully drain a 5t Fuel Tank.

Ion engine flare pre-1.5 update

  • The current ion engine seems to resemble a real-life type of Ion engine known as hall-effect thruster (HET). These need an easily-ionizable propellant in the cathode, but the restrictions are less strict on the anode, meaning oxygen or other rocket fuel could be used. However, in SFS, all fuel is interchangeable.
  • The sound it produces is similar to that of the sounds of the Valiant engine, the Kolibri engine and the Frontier engine.
  • It's the only greyed-out electrical part still available in the build sidebar (that doesn't have to be loaded from saves), unlike batteries and RTGs; however, it only uses fuel.
  • You can also get the Ion Engine via BP Editing. However, in 1.5.2 update, premium parts in the free version of the game does not work on blueprints and worlds due to not being owned.
  • The ion engine does not consume electricity at the 1.35 update.
  • The ion engine can be also called as an ion drive or an ion thruster.
  • Ion engines can create lights if they are clipped by a dimension of 2×2 square units.
  • Clipping another ion engine would indeed have more thrust.
  • Ion Engines only work efficiently in astronomical bodies with low or very low gravity.


  • Its thrust was increased in the 1.4 update, but its efficiency remained the same.
  • It consumed two units of electricity, equivalent to the production of two extended small Solar Panels or one extended large Solar Panel, until version 1.5, when the electric system was temporarily removed to be reworked. It no longer consumes or requires electricity, and the texture of the engine is changed, from black with silver and gold on top, is now just a plain black engine with gray on the bottom.
Basics ParachuteCapsuleHeat ShieldSeparatorFuel TanksHawk EngineValiant EngineKolibri EnginePeregrine EngineRCS ThrustersSide SeparatorSolid Rocket BoostersAerodynamic Nose ConeLanding Leg
6 Wide 6 Wide Aerodynamic Nose ConeFuel TanksSeparatorHeat ShieldEngine Base
8 Wide 8 Wide Aerodynamic Nose ConeFuel TanksSeparatorHeat ShieldEngine Base
10 Wide Fuel TanksSeparatorHeat ShieldEngine Base
12 Wide Fuel TanksSeparatorHeat ShieldEngine Base
Engines Titan EngineFrontier EngineHawk EnginePeregrine EngineValiant EngineKolibri EngineRCS ThrustersIon Engine
Aerodynamic Parts ParachuteSide ParachuteAerodynamic Nose ConeAerodynamic Fuselage
Fairings Fairing
Structural Structural Part
Other Docking PortLanding LegsIon EngineProbeRCS ThrustersWheelsSolar PanelFuel Pipe
Currently removed in Version 1.5