Ion Engine

The Ion Engine is an low-thrust, extremely high-efficiency engine that runs on both fuel and electricity. It ties with the RCS Thrusters as the smallest-footprint engine in SFS, at the size of 2x1 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 accelerate 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 Ion Engine can also be used as a high efficiency replacement for the RCS, because the RCS has terrible efficiency.

This engine was added to Spaceflight Simulator in version 1.35.

Trivia

 * The thrust of the Ion Engine in the game (19kN) is in kilonewtons, which is much higher than real Ion engines, which exert forces of millinewtons (mN).
 * In the game, it will take 4.5/(2/1020)/60=38.25 minutes for an Ion Engine to fully drain a 5t Fuel Tank, and it will provide 226.666...m/s of delta-v.
 * The current Ion Engine seems to resemble a real-life type of Ion engine known as hall-effect thruster (HET). These need an easily-ionisable 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.
 * 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.

Future

 * The game’s Future Updates menu says the electric system will be reworked, most likely with the ability to timewarp 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.

History

 * 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 Solar Panels or RTGs or one extended Solar Panel Array, until version 1.5, when the electric system was temporarily removed to be reworked. It no longer consumes or requires electricity, and the yellows have been changed to grey.