Spaceflight Simulator Wiki

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 always draining the closest reachable fuel tank.

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 21.25 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 Ion Engine is the quietest engine currently available.
  • The engine most likely uses xenon fuel, giving it a blue flame.
  • 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.


  • The game’s Future Updates menu says the electric system will be reworked, most likely with the ability to time warp during Ion Engine burns, but an estimated position in the version timeline isn't given. It could also imply the addition of a Stability Assist System to aid in warped burns.


  • 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 ParachuteCapsuleHawk EngineValiant EngineKolibri EngineFuel TanksSeparatorSide SeparatorAerodynamic Nose ConeLanding Leg
6 Wide 6 Wide Aerodynamic Nose ConeFuel TanksTitan EngineSeparator
8 Wide 8 Wide Aerodynamic Nose ConeFuel TanksSeparator
10 Wide Fuel TanksSeparator
12 Wide Fuel TanksSeparator
Engines Hawk EngineValiant EngineKolibri EngineTitan EngineFrontier EngineRCS ThrustersIon Engine
Aerodynamic Parts ParachuteSide ParachuteAerodynamic Nose ConeAerodynamic Fuselage
Fairings Fairing
Structural Structural Part
Other Docking PortLanding LegsIon EngineProbeRCS ThrustersWheelsSolar Panel
Currently removed in Version 1.5