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How to Near Future


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You're looking to, or you've already downloaded @Nertea's shiny, shiny things so the air filters on your Laythe base keep filtering, or so the cryogenic fuel in your Eeloo probe doesn't escape. :rep: 

But how do you use these exactly? How do you balance the reactors, engines, radiators and overall dry mass to get decent TWR, consistent burns and keep the reactors in their prime too? Here is all the introductory info you need to get you going.

Topics will be added over time so don't worry too much about things missing from this post. :) 


  • Reactor + Engine Balance
  • Reactor + Radiator Balance
  • Reactor Longevity
  • Reactor Control :rep: 
  • Capacitors
  • Capacitor Control (Soon)
  • Fuel Performance
    • Argon
    • Xenon
    • Refueling
    • Lithium


Reactor + Engine Balance
When picking a reactor, watch its Fission Generator > Power Generated value and Fission Reactor > Required Cooling value. When picking an ion engine watch its Propellants > EC consumption and you'll find that this consumption will tend to be exact to the output of a given reactor and that there are several more such pairings begging for you to notice them.

4wSzssA.png zoGnIid.png 


Reactor + Radiator Balance
Once you can keep in mind how much the Fission Reactor > Required Cooling of a given reactor is, it should be easy enough to look at the stock radiators and add or multiply their Radiator Specs > Core Heat xFer values. Once your total exceeds the reactor's Required Cooling value that's it, that's how many of that radiator you need. This is a good setup: 400kW from 2x large static radiator > 300kW from 1x Garnet. Also, never forget that static radiators must be attached directly to the reactor or its parent part or else. I don't need to install a radiator mod to show how to balance a reactor with them, but I would need to install one because stock radiators do have their limitations, and "options" are especially important for ion-powered vehicles that dare to pass through an atmosphere with their reactors running.

4wSzssA.png 8WXwQUY.png


Reactor Longevity
Don't get swept away with the power of a nuclear reactor that you decide to or completely forget to put an RTG or solar panel on your craft. Always include an alternate means of power generation so that the probe core can be kept alive and that you don't waste the reactor's nuclear fuel Enriched Uranium between the last orbital maneuver and the next. In flight there is the danger of the reactor overheating and the loss of core health (separate from core life). Core Health is expressed as a percentage and iirc, once health is lost, total output becomes capped and it can eventually meltdown and become dead and useless (I don't know if it explodes, haha). Core Life is the amount of time you get depending on how full it is with Enriched Uranium and what the output cap is. The output cap is controllable via a slider in the NF Reactor toolbar panel between 0 and full EC/s rate, technically allowing the reactor to run for decades or centuries as an oversized RTG.


Reactor Control

The final thing about nuclear reactors is, of course, how to operate them directly, especially from the snazzy NF GUI app. Look for this chEdX4h.jpg in your KSP toolbar once you have Near Future Electric installed and a nuclear reactor on the active vessel. (It does not show in Map View.) Every proper nuclear reactor mod out there should integrate into Near Future and can be controlled through it, and that makes life good. Such mods (that I know of) include USI Core and Mk2 + Mk3 Stockalike Expansion but exclude KSP Interstellar which changes all nuclear devices in its own way.


Do not expect this to control any radiators associated with a reactor. Those must be toggled separately.

The UI Elements are as follows:

  • The radio (circle) button under a reactor name is the main switch and lights up when toggled on.
  • The thermometer (with two checkpoint markers) respectively indicate the thermal range, the peak operating temperature, and the overload/shutdown temperature. The number will always be the temperature at a given moment.
  • The three symbolic items above the thermometer represent kilowatt output (not necessary to most of us), the ElectricCharge output (most important) and Core Life (very important). When a reactor is on it will show you the duration in years instead of "Reactor Offline".
  • Basic Controls is the output control slider (at 100% by default) which lets you finely control the ElectricCharge output. Accordingly, the kW, EC and Core Life values over the thermometer will change. Most of us don't need to click Advanced Controls. I didn't, so I don't even know what that looks like.


This screenshot features the 2.5m USI device with its context window open and the NF control window. Note that in both GUI its output slider is set to 25%. Both windows have their distinct advantages, but NF's window shows you what matters right now, and for all your reactors if you have more than one, removing the need to pin all your reactors' context windows if you ever have to access them all at once.

You do not want to end up like this!

In the odd chance that you visit an infernal planet and decide that solar panels were not necessary...or they are present but useless at the time, make sure to never leave things on that will guzzle the current. In this case I had a life support device on and the ship's radiators were maxed out, causing them to fail to cool the reactor, which in turn led to the reactor gradually overheating, losing output efficiency, and nearing its overheat/shutdown temperature. If it reaches its shutdown temperature and does not receive cooling, it will remain super-heated and its Core Health (the percentage status of the core, not the output duration bit) will start to fall, meaning it's decaying and it will become a metal brick. As long as it is hot it will decay. If there's a separate power source able to feed the radiators and cool the reactor down, the decay will stop.




As @Supercheese mentions below (which helps me a lot in do this part, so thanks muchly :) ) installing capacitors instead of a reactor can save cost and weight and increase deltaV by quite a lot. As shown in the first picture, you get 8x the amount of StoredCharge to ElectricCharge for the same mass and volume of the part. Each part here weighs 0.25 tons but one quarter-ton of capacitor shines brightly against 2 whole dark tons of normal battery. (Stock 2.5m batteries featured here)

While that is a great thing, they have their disadvantages. They are not a 2-way street like batteries and cannot be used out of while they're charging. A capacitor can be paused from charging (and when charging it will feed from everything that produces or stores ElectricCharge) but it cannot be paused while discharging (in doing so it will feed everything that stores or consumes ElectricCharge).

You can control* the discharge rate of a capacitor in the VAB and in flight at the Near Future Capacitor toolbar button. As shown in the second picture: because the visible ion engine consumes 1999 EC/s I set the discharge rate to just over that to feed the engine and any vital systems. Unfortunately, as far as I know, you must manually discharge capacitors in series to feed your engines. If you discharge them all at once that's quite literally wasting tons of power.

* There are certain lower limits to the discharge rate depending on a capacitor's size which will occasionally force you to add an engine or else waste a portion of the released power.

7Zs1ETO.jpg 0fMG2PB.jpg

Even if for some reason you end up stacking a reactor's weight or more in capacitors (and heavy, heavy solar panels...) on a craft, you're still saving more than just cost. You're avoiding the troubles of nuclear fuel and reactors themselves if you're still skeptical about the things, but you'll remain at the mercy of solar panel efficiency if you're operating very far from a star.

The next thing to consider is how many capacitors set at a given discharge rate will afford a consistent engine burn up to a desired maximum length. The reference formula to measure by is very simple:
Total StoredCharge / Discharge Rate = Maximum burn time in seconds.


Fuel Performance
If you're a nut for fuel performance, then here are a few opening stats including engine sizes to help weigh Near Future's propellants in your mind before you read about them below.

  • Argon Engines
    1 ~ 54.55 kN, 2800 ~ 5500 Isp
    0.6m, 1.25m, 2.5m
  • Xenon Engines
    1.4 kN, 4000 Isp (Stock Dawn engine)
    2.3 ~ 5.6 kN, 6500 ~ 19300 Isp (Added engines)
    0.6m only
  • VASIMR Engines (can halve their Isp for nearly triple thrust, no change in propellant consumption)
    Xenon mode: 4 ~ 68 kN, 6000 ~ 7000 Isp
    Argon mode: 2.5 ~ 44 kN, 8500 ~ 9500 Isp
    0.6m, 1.25m, 2.5m
  • Lithium Engines
    46 ~ 237 kN, 2900 ~ 3800 Isp
    0.6m, 1.25m, 2.5m


I personally prefer ArgonGas over XenonGas because it's more abundant in-game (as it is irl) than Xenon and is hence easier to harvest from Duna and other planets with atmosphere. Here I modify a  probe that was never meant to go far from wherever it's deployed, to (almost) be able to cross SOI. Almost = not enough fuel but there's plenty, plenty room to fix that. Adding a radial Argon tank (or 4) and changing the Garnet to its TopNode subtype so I can attach things to its other end.


eb40jhE.jpg ePy1XuB.jpg

Here's a Xenon-powered Duna probe I launched soon before KSP 1.2.0 was even announced. This is 6 tons, 1 TWR in low Mun orbit iirc, and 11km's dV! The Garnet reactor underneath has 2x Radiator Panel (edge), the straight ones with 150kW cooling power directly attached and they're exactly enough (300kW together) to keep it at/within its limits (300kW). The particular Xenon engines on this one have been deprecated so I can't explore them now.



There are two mods I know of that supply a means not just to use Argon or Xenon, but to replenish your tanks.

The first is Karbonite, part of USI. Its low-altitude atmosphere scoops come in 1.25m and 2.5m size. They have very poor intake values since they are firstly filter type devices, and they operate better the faster you're moving and the thicker the atmosphere. Strap some of these, a karbonite power cell and a USI kontainer (for Argon) or a stock Xenon tank to your airplane and fly around (if you have the patience or an autopilot mod). Have the scoops filter karbonite too to feed the power cell and even better, feed some karbonite jet engines so you can infinitely fly and refuel faster.... Or you know, spam them on a landed craft and do the timewarp disco.

(Forgive me for mentioning so much karbonite.)



Then there's Near Future, of course. It provides the AIReS Atmospheric Sounder (Science category) and the M-2 Cryogenic Gas Separator (Utility category) for harvesting Argon and Xenon. The AIReS is a scanner and both parts only work in atmosphere. Unlike karbonite's scoops, the M-2's performance is not influenced by whether it's moving, and it consumes between 12 and 24 EC/s, or 12 + 24 depending on which gas, or both, you're processing.



The story isn't very different for lithium-fueled crafts, except that Lithium, being a solid material is much denser than Argon and Xenon and that makes it better for crewed ion vessels. TWR is much better at the cost of Isp, and empowers heavy landers and even enables Duna SSTOs. I've made Argon-fueled SSTOs (in KSP 1.1.3) but those required very, very tedious mixing and matching of USI and NFT's reactors, karbonite scoops (to refuel themselves), and engines for sufficient dV and TWR. I don't know if it's still possible now. I haven't been at this kind of thing since KSP 1.2 arrived. Sometime perhaps I will post examples of a perfected ion-powered SSTO.

Near Future Propulsion adds Lithium modules to the stock drills and stock ISRU (and the ISRU of Kerbal Planetary Base System if also installed).

Here we have an Augustus-capable Lithium SSTO prototype. Since I always have Galileo's Planet Pack installed, I have KER set to Augustus, a moon, and it compares as follows:

  • Augustus: 0.35g, 65km atmo, 350km radius.
  • Duna: ........0.30g, 50km atmo, 320km radius.

The Garnet reactors have just enough cooling and this Lithium engine pairs it perfectly for EC flow. The 3 tons of Ore simulates precious cargo like LS resources. Full or empty, though, this craft can make it (however, it's not aerodynamically sound). When devising a Lithium-driven vessel and want to make your engine setup controllable, make sure to add this to your procedure:

  1. Setup the reactor on its own stack and if possible, attach all the needed radiators to it.
  2. Attach its complement engine and if necessary, nerf the engine so it doesn't drain more EC than is produced (this is only necessary for the huge engines).
  3. Take that stack now and multiply it with symmetry until you get a satisfying number for TWR. This only really matters if you want to land or launch in atmosphere. With the prototype craft below, 2x is not enough and 4x is even better. But this isn't always the case. Diminishing returns are hard to avoid or control, especially when the payload fraction goes up from here.

CdR56xq.jpg HRgIiSl.jpg

Here's a mothership I launched from Minmus. It doesn't claim to be an SSTO but it had about 6km/s dV fully loaded and had some LFO and roughly 1.2km/s for its VTOL mode and a tiny chemical rocketed lander. it was rated for operation with the surface gravity of Vall which is greater than that of Mun. It also contained 3x Near Future's 8 ton Prometheus reactor and 6x 1.25m Lithium engines.


Edited by JadeOfMaar
added reactor control UI
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This is good stuff! However, I saw you didn't mention Capacitors at all. Capacitors can be a great way to reduce costs and increase Δv on ships: If the primary EC requirement is the main engines -- and it likely will be, because they can be very, very EC-hungry -- you don't necessarily need to have enough reactors to cover 100% of the EC/second consumption of the main engines at full tilt. Instead, you can have a modest battery storage paired with capacitor banks which are slowly charged by a smaller reactor or solar panels. The capacitors can then be discharged to power the main engines during periods of acceleration, and trickle-charged during the long transit times between burns.

Capacitors have a much, much higher EC/ton than batteries (160,000 EC per ton for Capacitors vs. 20,000 per ton for Batteries) and a much lower cost per EC as well. It does require more micro-management since you need to open Near Future's capacitor panel to control discharge/recharge, but the potential cost and weight savings are rather enticing. :)

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Thank you thank you and thank you...for creating this thread!  In one post, you have answered several of my lingering questions (pairing EC sources/storage to heavy use EC engines, situations in which to use the different engines/ECs/fuel types, examples of crafts and, best of all, the theory behind capacitor use and how to best optimize).  

I now have the needed info to fine tune my nucleo-capacitor ship...it will have enough dV so that Jeb doesn't feel guilty sneaking extra doughnuts for the long trip to Jool. :)

Edited by Red Stapler
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  • 2 months later...
  • 2 months later...
On 2/28/2017 at 5:55 PM, JadeOfMaar said:



You've not addressed the little gear icon next to the ON button. It pulls up a bunch of rather ominous important looking other icon buttons, none with any explanation. Before I go clicking things randomly and exploding things (as entertaining as that can be), what do those little icons in the sub menu do?

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17 minutes ago, CatastrophicFailure said:

what do those little icons in the sub menu do?

That's just a picker for alternate icons.

They're completely harmless. Oh, an you can rename the reactor (only applies within that window).


Edited by JadeOfMaar
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  • 6 months later...

Yes, it is. I've never seen a complaint on this subject concerning Nertea's mods.


I'm playing with TAC life support and I seem to be losing power when I'm not controlling vessel, yet when I switch to it it seems to be charging fine with enough power. Maybe a rare bug?

Edited by cpx
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9 minutes ago, JadeOfMaar said:

@cpy That's a problem with TAC life support and its included background process plugin. It's not a Near Future problem, sorry.

Fair enough, now to figure out what is causing it TAC or background process plugin. I checked it before but background plugin seems to be dead project.

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  • 2 years later...

I'm doing a Community Tech Tree playthrough using Near Future and I've finally reached VASIMR engines, so I'm going to need industrial quantities of Xenon or Argon.  The ship I want to use and re-use would cost over 400,000CR just to top up the gas.

I created a test-bed, to see if I can synthesize the gases on the ground, but for some reason none of the M-2 units are producing anything close to the 0.5 per second that they're supposed to.  Instead they're producing at 0.000285/sec.

Also, is there a way of producing Xenon from something in the ground?  I would love to be able to refuel my VASIMR ships from the moon, but it has no atmosphere.


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  • 3 weeks later...

Hi, in the VAB there is the Near Future Systems Manager, in "Electrical" there is the "Solar Panel Simulator" and there is "Mean Solar Altitude", its value higly determines the energy output, there is a value between 5 and 500 Gm, what does Gm mean? Grades? , how can I use the Manager effectively to calculate solar panel needs? Specially if in planning to go Jool or further (i know solar may not be the best option though). Thanks

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38 minutes ago, juvilado said:

what does Gm mean

Gm stands for "Gigameter" and 1Gm = 1,000,000,000 meter so for the simulator, this is your distance to the sun. The KSP wiki says, Jool has a Pe of 65,334,882,253m (or ~65Gm) and an Ap of 72,212,238,387m (or ~72Gm), so if you run the simulation for these distances, you should be able to figure out how much power your solarpanels will generate.

I'm not sure if the game provides these distances somewhere ingame, I'm used to look it up in the wiki if I need some basic numbers^^

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The UI provides you with a button you can click to set the Mean Solar Altitude to that of a target body. In your use case, set it to Jool, and you will see all solar panels are scaled to their predicted output at Jool

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  • 3 months later...
2 hours ago, dlrk said:

Sorry to bump, but is there a newer version of this thread, or some more info on capacitor use anywhere?

Sorry. No to both. I haven't casually played in a long, long time, so I don't know how much my info has become obsolete by now.

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