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)
  • 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!


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    10.7k Kell

    @ShadowPlane Forums could work

    6 months ago
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    @mjdfx150529, I think physics battle in comments is not good idea. Has this website a special place for discussion?

    6 months ago
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    10.7k Kell

    @ShadowPlane It is specific impulse

    6 months ago
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    Stop! I don't understand: 5000 s is specific impulse or specific thrust? @mjdfx150529

    +1 6 months ago
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    10.7k Kell

    @ShadowPlane It’s ok

    6 months ago
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    Ok, @mjdfx150529. I'll read this Wikipedia articles.
    @AndrewGarrison, I want a nuclear engine!
    Theory isn't practice. And physics is difficult. Sorry, @mjdfx150529.

    +1 6 months ago
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    10.7k Kell

    @ShadowPlane
    The in game ion engine is already quite powerful, in real life, Hall effect thruster get about 83mN to 5.4N of thrust with a power consumption of 1.35kW to 100kW. According to wikipedia

    6 months ago
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    10.7k Kell

    @ShadowPlane
    First of all, according to this Wikipedia article, specific impulse equals to Ve / g.
    Second of all, kinetic energy is 1/2 * m * v^2. Not m * v, that’s momentum.

    6 months ago
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    @mjdfx150529, your analysis is little WRONG! If exhaust velocity is 40000 m/s, then Isp is 40000 s too, because, I read in Wikipedia, Isp (in theory) equal to exhaust velocity. But you, for some reason, divided exhaust velocity on 9.81: "40000 / 9.81 = 4077s". Gravity isn't affect to Isp.
    Now about energy. Kinetic energy = m * v. Because from engine fly continuous flow, this flow needed to split to equal time parts. 1-second flow impulse equal to force (thrust) of engine (I don't want to explain this. I'm tired). Impulse / t = kinetic energy / t, and this means kinetic energy / t = force (thrust). If in KSP ion engine has thrust in 2 kN (2000 N) and power = energy (kinetic) / t, then power = 2000 W (or 10000 W with efficiency factor). But you, instead W from N, got kW from хуй знает, что: "112962 * 50 / 2 = 2824kW".
    Now, engine characteristics:
    Thurst = 2 kN
    Specific Impulse = 40'000 s
    Electrical Consumption = 10 kW
    @AndrewGarrison, please, accept my calculations! I want to fly on the Mars (or как его там) and other planets. But 20 N - it's nothing! My calculated characteristics is agreeable. I think, my calculations is right.
    Ну что, @mjdfx150529, понял, кто тут физик!?

    6 months ago
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    118 JetFly

    @SpaceWC there will be gyroscope units

    9 months ago
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    it that expensive?

    9 months ago
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    Very nice thrust force

    10 months ago
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    I think so. @ThatoneMArtist

    10 months ago
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    @AndrewGarrison @HellFireKoder did you know who invented this technology? :)

    10 months ago
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    @Caveman999 so in career mode will there be contract missions?

    10 months ago
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    @Caveman999 sorry?

    +1 11 months ago
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    @Caveman999 Well ok... It would be $100,000 dollars...

    11 months ago
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    He means the price of the ion engine. @AstronautPlanes

    11 months ago
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    @MAHADI Andrew already posted it, it would be the same prize as SimplePlanes

    11 months ago
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    I’m no. 5 and I have 11. @Nooneoone

    11 months ago
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    In 2 weeks. @TrustMeImanEngineer380380

    11 months ago
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    Career mode you will need to buy parts. Sandbox mode is free. @MAHADI

    11 months ago
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    154 MAHADI

    Cool! But what is the price tag for?

    11 months ago
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    548 MyMessage

    Yeah @Nooneoone

    11 months ago
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    @MyMessage yeees i remember that game. Sad to see it fall into the past

    +1 11 months ago
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