The tyrannical Tsiolkovsky rocket equation cannot be avoided. The only way for rockets to accelerate in space is by expelling some of their mass. Most engines do this with combustion, which expels huge amounts of fuel mass at a respectable velocity. This gives great acceleration (and an impressive fireball), but very poor specific impulse. Specific impulse is like gas mileage for rocket engines.

Ion engines, on the other hand, take a different approach.

They shoot out a minuscule amount of fuel mass, but they do it at insane velocities. Around 40 kilometers per second (90,000mph). This results in a force that is about the equivalent of lifting a piece of paper into the air. That's not very impressive, but they make up for it by taking their time with their fuel. Ion engines can "burn" for weeks, so this small force can add up to an extremely impressive delta-V.

This little satellite I made has a delta-V of 14,533 m/s and a burn time of about 72 hours.

Here are the details:

Thrust: 0.020 kN (Yep, that's right, just twenty Newtons)

(Yep, that's right, just twenty Newtons) Mass: 50 kg

Price: $100,000

Specific Impulse: 5,000 s

Fuel Type: Xenon

Electrical Consumption: 245kW

Height: 0.25 m

Diameter: 0.6 m

Max Gimbal Angle: 0 degrees

Given the extremely long burn times, these engines aren't very useful when playing the game at normal speed. This weekend I've been prototyping how to use these engines while playing the game at up to 1,000x fast-forward mode. It makes playing with these engines far more enjoyable.

Edit: Engine thrust, specific impulse, and electrical consumption have been adjusted. Thanks @mjdfx150529 for the analysis and letting us know the engine is violating the laws of physics!