[0.90] KSP Interstellar port maintance thread

[etmoonshade]

This is one of the newest changes Fractal made before disappearing. Probably why it hasn't been updated in the wiki. 0.13 changelog states that thermal rocket ISP is now capped at 3000

Version 0.13
-Added magnetic nozzles
-Capped thermal rockets at ~3000s Isp
-New refinery system with vastly improved GUI
-Integrated computer cores and AI with the stock science system
-Fusion reactor fuel scaling drastically changed to make alternative fuels more efficient
-Decreased fusion fuel consumption to more realistic values
-Attach node sizes fixed

Greening, your problem may also be stemming from this. To balance this, would it be proper to raise the thrust levels?

Yeah, there's got to be something done about that - that's just wonky, counterintuitive, and makes it so there's no real advantage to using antimatter. That also explains other little wierdnesses I've noticed and chalked up to me "doing something wrong" somewhere.

Do we know if there's a particular reason he capped thermal rockets at 3ks Isp? If it's just a game balance issue, maybe apply some sort of scaling factor after 3ks to give it a curve.

Also, did the equations used change? Because I can't make any sense out of the numbers I'm getting in testing. For a NTR with a 1.25m Fission reactor, I'm getting a vacuum Isp of ~2700s... calculation based on the tooltips is giving me 2100s though. And obviously the cap is making the numbers for antimatter thermal rockets really weird.

</early morning ramble>

[Atrius129]

Yeah, there's got to be something done about that - that's just wonky, counterintuitive, and makes it so there's no real advantage to using antimatter. That also explains other little wierdnesses I've noticed and chalked up to me "doing something wrong" somewhere.

Do we know if there's a particular reason he capped thermal rockets at 3ks Isp? If it's just a game balance issue, maybe apply some sort of scaling factor after 3ks to give it a curve.

Also, did the equations used change? Because I can't make any sense out of the numbers I'm getting in testing. For a NTR with a 1.25m Fission reactor, I'm getting a vacuum Isp of ~2700s... calculation based on the tooltips is giving me 2100s though. And obviously the cap is making the numbers for antimatter thermal rockets really weird.

</early morning ramble>

He did it so that Magnetic Nozzles would have their own niche. I don't think he had a lot of time playtesting it though. I really really wish RoverDude would take KSPi under his wing and branch it into USI.

[FreeThinker]

Do we know if there's a particular reason he capped thermal rockets at 3ks Isp? If it's just a game balance issue, maybe apply some sort of scaling factor after 3ks to give it a curve.

Not sure, but I guess it's to create some distance between Thermal Noozle and Magnetic Noozle. But I agree this nerves Anti Matter engines, that's why I added a configuration setting called MaxThermalNozzleIsp that allows you to set you own maximum ISP. In my own KSPI mod I cap it at 5000 ISP, which is high enough not to cap any engine.

Edit, you can download a patch for KSPI 0.90 which includes the MaxThermalNozzleIsp setting from KerbalStuff.

Edited January 18, 2015 by FreeThinker

[Atrius129]

Not sure, but I guess it's to create some distance between Thermal Noozle and Magnetic Noozle.

KSPi OP:

New in Version 0.13

• A revamped refinery ISRU system giving you more information about what resource processing is going on, the amount of power it's using and generally reduced clutter
  
• New Magnetic Nozzles that give really nice high Isps when coupled with charged particle reactors
  
• Thermal rocket balance significantly changed to accomodate the new magnetic nozzles
  
• Computer Cores and Science labs integrated into stock science
  
• Massive changes to fusion reactors making alternative fuels much more viable (plus a reduction of fuel consumption with all fusion reactor fuels to make the rates more realistic)
  

But I agree this nerves Anti Matter engines, that's why I added a configuration setting called MaxThermalNozzleIsp that allows you to set you own maximum ISP. I in my own KSPI mod I cap it at 5000 ISP, which is high enough not to cap any engine.

That is great. Thank you. I have been looking for this. Rep+

- - - Updated - - -

That is great. Thank you. I have been looking for this. Rep+

Thought that was a link to a config file. Do you have just that config available? I don't use NFT.

[GreeningGalaxy]

The Isp cap thing in general is just borked. I get that there are going to be factors limiting the specific impulse of thermal rockets, but having just a hard limit there is weird. I could live with that, though, if all the energy you put into a thermal rocket actually showed up again - I'd expect it to appear as thrust. It does appear to do that for the most part, but there are some glaring exceptions. Sure, you'll have some losses since no system can be 100% efficient, but what you lose is still going to show up as waste heat - you can't just wave a magic wand and make excess energy go away. That's what appears to be happening on the antimatter thermal rockets - no noteworthy waste heat is being generated, the Isp is still low, an the thrust, while pretty intense for a chemical rocket, isn't remotely what it should be for a 405 gigawatt antimatter one. Unless the overwhelming majority of the power is being lost as gamma rays or only heating the exhaust after leaving the engine or something, we've got a thermodynamics problem on our hands.

Of course, it would also be reasonable to expect that a 405 gigawatt engine with an Isp of only 3,000 seconds would totally break any vessel at full throttle, regardless of how strong it's built. If we assume an efficiency of 50%, that gives us a thrust of (405,000,000,000 W / (3,000 s * 9.81 m/s/s * 1/2)) * 50%, or just over 13.8 giganewtons (13,800,000 kN).

Not on my ship, thank you very much!

In reality, you'd never get a thrust that high by any realistic means (note that nothing on the Project Rho table goes above about 400 meganewtons or so). The propellant flow would just be too big to manage, and you'd inevitably end up with a substantially higher Isp. Of course, that wouldn't literally be a thermal rocket at that point - it would presumably be more akin to the plasma core antimatter rocket (Isp ~700,000 seconds, thrust ~50 kN for a 192-gigawatt system), which is a low-thrust high-Isp system, exactly the opposite of what the 3000-second Isp cap seems to suggest it would be. It could, of course, be "geared" by pumping through more or less propellant, exchanging Isp for thrust to a certain extent, but I have a hard time believing that it'd be able to gear itself as low as 3,000 seconds. (I may also point out that the 405-gigawatt antimatter reactor specifically identifies itself as "Plasma-core" - this isn't that hard, people. )

I don't really know what's up with KSPI these days, but I really feel like putting the 3,000-second Isp cap on the antimatter thermal rockets did nothing for realism or gameplay. At the very least, I think the engine should have its power output/input balanced, if not be reworked to model a completely different engine type.

Edited February 28, 2015 by GreeningGalaxy

[Atrius129]

^^

All of this. I'm really hoping FreeThinker will come through with that config and that it works well.

I found where MaxThermalNozzleIsp was referenced in the warppluginsettings.cfg, but I cant find it's actual config file.

[FreeThinker]

^^

All of this. I'm really hoping FreeThinker will come through with that config and that it works well.

I found where MaxThermalNozzleIsp was referenced in the warppluginsettings.cfg, but I cant find it's actual config file.

Alright, I will make it super easy for you, you can download the KSPI 0.90 Patch from KerbalStuff which you only have to extract into your Interstellar Folder (GameData\WarpPlugin). The ConfigurationFile includes an increased MaxThermalNozzleIsp setting of 5000. Besides this setting, I also added several other new config settings (with Default KSPI values) which allow you to tweak KSPI yourself.

Edited January 18, 2015 by FreeThinker

[Atrius129]

Alright, I will make it super easy for you, you can download the KSPI 0.90 Patch from KerbalStuff which you only have to extract into your Interstellar Folder (GameData\WarpPlugin). The ConfigurationFile includes an increased MaxThermalNozzleIsp setting of 5000. Besides this setting, I also added several other new config settings (eith Default KSPI values) which allow you to tweak KSPI yourself.

That is rather excellent. Thank you.

[thedarkdevil420]

well, while loading, it just stops at loading aluminumhybrid1. just dead. no loading any more. i have tired removing every other mod i have installed but that does not help. what should i do? please help. thanks in advance

[FreeThinker]

well, while loading, it just stops at loading aluminumhybrid1. just dead. no loading any more. i have tired removing every other mod i have installed but that does not help. what should i do? please help. thanks in advance

I had this problem too after I upgraded to 0.90. I fixed it by creating a fresh new install of KSP

[Atrius129]

well, while loading, it just stops at loading aluminumhybrid1. just dead. no loading any more. i have tired removing every other mod i have installed but that does not help. what should i do? please help. thanks in advance

well, while loading, it just stops at loading aluminumhybrid1. just dead. no loading any more. i have tired removing every other mod i have installed but that does not help. what should i do? please help. thanks in advance

It sounds like you didn't remove the old KSPi files first before installing Boris's version. Delete all KSPi folders, including dependencies, then reinstall. Also ATM would probably help you out a lot.

[Northstar1989]

Hi Boris,

I was wondering if you had enough programming/modding expertise to attempt implementing a feature that FractalUK already expressed an interest in adding to KSP Interstellar, but said he regrettably did not have time to code in himself. I was hoping you could then send a Pull Request to get it in the main mod when FractalUK has KSP Interstelalr back up-to-date for 0.90

The feature I was hoping you could add was the use of Nitrogen as an ISRU and fuel resource.

Basically, Nitrogen should be harvestable with an Atmospheric Scoop on Kerbin, Laythe, and Eve (corresponding to the relatively high nitrogen contents on Earth, Titan, and Venus, respectively... 78.084%, 98.4% of the stratosphere and upper atmosphere, and 3.5% respectively) using the existing ISRU system.

Nitrogen should then be usable as a plasma thruster fuel (corresponding to the real life Helicon Double Layer plasma thruster) and as a thermal rocket fuel (thermal rockets can run off basically any non-corrosive gas).

FractalUK already expressed interest in coding both of these into the KSP Interstellar mod- but implied he didn't have the time for it. He also said he didn't have a good model to use for a fuel tank part that could hold nitrogen (the linked post discusses the issues with tankage).

The last of these issues (the fuel tank) could be filled as a stopgap measure by re-using the textures for one of the stock fuel tanks. Or, alternatively, you could implement a tweakable fuel tank the players could *choose* what to fill it with- much like the current tweakable fuel tanks in the Firespitter, B9 Aerospace, Modular Fuel Tanks, and Real Fuels mods... I'm sure FractalUK would be *highly* appreciative if somebody could do a quality job coding up such a long-term solution (a tweakable tank) for an increasing number of resources he wants to simulate...

As a side-note, the RealFuels mod already has accurate parameters for its Nitrogen resource (called "N2" in the resources .CFG). KSP-Insterstellar has already shown a commitment to including some realism with things like water electrolysis producing an accurate mass-ratio of Hydrogen ("Liquidfuel") to Oxygen ("Oxidizer") despite the fact that they currently *burn* in an inaccurate 10:11 ratio in the stock game; and with realistic ISRU possibilities instead of a single "magic" ISRU resource like in Karbonite or Kethane...

As such, it seems appropriate to utilize realistic density values for Nitrogen- which RealFuels mod conveniently already makes available (as one of the creators of a KSP-Interstellar/RealFuels integration config, I also have a vested interest in seeing both mods use the same resource definitions for Nitrogen- it makes ensuring mod cross-compatibility *MUCH* easier...) This also helps when using the Procedural Parts mod to create custom size Nitrogen tanks- as Procedural Parts already has definitions included for resource capacities for RealFuels-density Nitrogen (as a gas, Nitrogen is actually compressible into a much smaller volume- which is already accurately reflected in the increased Nitrogen capacities of Procedural Parts Service Modules...)

Regards,

Northstar

P.S. The ability to use Nitrogen in a plasma thruster makes Propulsive Fluid Accumulator satellites possible and *profitable* in KSP Interstellar, as the mod already includes the necessary nuclear reactors or Microwave Beamed Power networks (I've actually already built Propulsive Fluid Accumulator satellites before to scoop Oxidizer in KSP-I, but the low ISP of LFO-burning engines ensures that it is impossible to scoop enough Oxidizer to replace the fuel mass you expend counteracting drag... It *is* possible to build profitable designs when running RealFuels, as LH2 and LOX burn in a 1:8 mass-ratio, but then you have to worry about LH2 boil-off, and still have to send up regular fuel-tankers with LH2- *not* an issue with nitrogen propellant...)

Edited January 19, 2015 by Northstar1989

[Magion]

I agree with Northstar. N2 harvesting would be very cool.

It's great that someone maintains KSPI, while FractalUK is missing. Thanks Boris!

Unfortunately, this KSPI version is pretty buggy. I can see following exception in log several times immediatly after loading KSC scene:

[KSP Interstellar] Exception caught adding to: smallerMPD part: System.InvalidOperationException: Operation is not valid due to the current state of the object
at System.Linq.Enumerable.First[ModuleInfo] (IEnumerable`1 source) [0x00000] in <filename unknown>:0 
at FNPlugin.PluginHelper.Update () [0x00000] in <filename unknown>:0 

Next, please comment this line. It's spamming my log and loads the processor to no purpose.

Microwave relay system appears to be broken too. I have to switch between relay vessels several times until they works as they should.

I hope it gets fixed soon

[FreeThinker]

I wondered why Nitrogen it's wasn't implemented as well, I shouldn't be that hard considering it just another resource. I will look into it.

Regarging the Nitrogen called "N2", I could not find it, what I did find was:

RESOURCE_DEFINITION
{
  name = Nitrogen
  density = 0.000001251
  unitCost = 0.00000005004
  flowMode = STACK_PRIORITY_SEARCH
  transfer = PUMP
  isTweakable = True
  ksparpicon = RealFuels/Resources/ARPIcons/Nitrogen
}

I'm not sure if I want to use this resource definition as propellant resource because it's density is really low. A far more conveniant/realistc method of transportation would be liquid nitrogen. According to Wikipedia Nitrogen at liquid boiling point weight 0.808 g·cm3 = 0.808 kg/L = 0.000808 ton/L. So I want to introduce the following resource:

RESOURCE_DEFINITION
{
  name = LiquidNitrogen
  density = 0.000808
  unitCost = 0.00003232
  flowMode = STACK_PRIORITY_SEARCH
  transfer = PUMP
  isTweakable = True
}

I found some intresting data that allows me get some meaningfull NTR data. According to the data, a 3700K NTR with Hydrogen generates 8,093 m/s. Nitrogen only produces 2,649 m/s at the same Temp. From this I conclude that the ispMultiplier should be 0.3273 !!

Therefore intend to use the following NTR PROPELLANT settings:

BASIC_NTR_PROPELLANT
{
    name = Nitrogen
    guiName = Nitrogen
    ispMultiplier = 0.3273
    isLFO = false
    PROPELLANT
    {
        name = LiquidNitrogen
        ratio = 1
        DrawGauge = True
    }
}

Edit: Notice, that Nitrogen is actually already used in the "Haber Process" for the production of Ammonia, but it was only required to be present in the atmosphere. I have added the resource and technically everything should work already. Tomorrow I will look if it will actually works for the production of Ammonia outside an atmosphere and be used in Thermal and electrical engines (using some made up values)

Edit: Alright, everything is working now, but I'm starting to understand why Fractal left it out, it's might be a bit overpowered as it effectively allows you unlimited gathering of propellant from Kerbin atmosphere. It would allow you to launch empty Nitrogen Tanks, collect nitrogen from an elliptic orbit and travel to any planet/moon, return to kerbin and repeat. On the other hand, it will take quite a long time to gather significant amount of propellant from the upper atmosphere to refill a nitrogen rocket

Edit: I'm realy not sure if Nitrogen should be allowed as an electric propellant. For one I haven't found any data to support it is possible. Sure there is such a thing as a Helicon Double Layer Thruster but it is a different type of engine than the Electric Plasma engines in KSPI. Also for game balancing reasons it might be inadvisable because it would be too good as a the "one resource to rule them all". For now, I won't include a definition for nitrogen as electric propellant (but it would work if you added yourself). Perhaps I could introduce a Magnetic Nozzle NTR motifier to make Nitrogen more effective with Magnetic Nozzle as compensation for the lack of a true Helicon Double Layer Thruster.

Alright, you can download the patch KSPI Extended 0.2 from KerbalStuff

Download, extract in the GameData folder and profit!

Edited January 21, 2015 by FreeThinker

[sidfu]

if u can figure out what the engine stats are for when they use them. making the other changes like adding as a resouce isnt hard.

[FreeThinker]

please comment this line. It's spamming my log and loads the processor to no purpose.

Microwave relay system appears to be broken too. I have to switch between relay vessels several times until they works as they should.

I hope it gets fixed soon

Good find, I will fix it in my next publish

Edited January 20, 2015 by FreeThinker

[FreeThinker]

Say, perhaps we can use Nitrogen in more ways than just a propellant, we might use it to cool reactors. According to this article, it would cut days from the cooling down time of a reactor. I wonder if it would also work realistically in space...

Edited January 21, 2015 by FreeThinker

[Atrius129]

Say, perhaps we can use Nitrogen in more way than just a propellant, we might use it too cool reactors. According to this article, it would cut days from the cooling down time of a reactor. I wonder if it would also work realistically in space...

I see no reason that it wouldn't work. If it is an open system, it would probably even be more effective than on terrestrial based reactors.

[FreeThinker]

I see no reason that it wouldn't work. If it is an open system, it would probably even be more effective than on terrestrial based reactors.

Yes, we could use it as a kind of super reactor coolant, that would drastically help to lose waste heat allowing for maximum power output.

[Atrius129]

Yes, we could use it as a kind of super reactor coolant, that would drastically help to lose waste heat allowing for maximum power output.

You could even add the RCS thruster animation to the reactor while doing the cooling procedure to make it look like you are venting. Also, N2 wouldn't be the only thing you could use. LH, LHe and a few other resources could be exploited as well. I think Mr. Manley mentioned this should be an option in one of his early IQ videos.

Edited January 21, 2015 by Atrius129

[FreeThinker]

The last of these issues (the fuel tank) could be filled as a stopgap measure by re-using the textures for one of the stock fuel tanks. Or, alternatively, you could implement a tweakable fuel tank the players could *choose* what to fill it with- much like the current tweakable fuel tanks in the Firespitter, B9 Aerospace, Modular Fuel Tanks, and Real Fuels mods... I'm sure FractalUK would be *highly* appreciative if somebody could do a quality job coding up such a long-term solution (a tweakable tank) for an increasing number of resources he wants to simulate...

Correct me if I'm wrong but from my understanding there are already several tweakable fuel tank mods. The problem however is that they only allow tweaking the fuel type inside the editor but not durring the mission after you consumed all your premium fuel. Instead of just throwing you empty tanks away, what you really might want to do is be able is to refill those empty premium fuel tanks with different kind of fuels which you can find in the local environment atmosphere/seas (nitrogen, hydrogen, methane, etc). For example, a empty fueltank that used to store liquid hydroden should be suitable to refill with liquid nitrogen. Now such tweakable fuel tanks would be a truely usefull, especialy for grand tours .

The problem of implementing this, is that ksp resource model is fixed in stone once you launch the game to real time. A possible solution to this problem is to bypass KSP resource system and introduce a custom resource system, that allows editing the configuration of a fuel tank on the fly. Preferable, this custom resource framework would also fix the issues related to high time warp. Currently, KSPI stores large amount of waste heat and mega joules just to make high time warp possible. This is essentially a hack which introduces game unbalances when playing in normal time where they act as unrealistic large heat/energy sinks. Anyone know such a resource model?

Edited January 21, 2015 by FreeThinker

[FreeThinker]

Alright, you can download the patch KSPI Extended Configuration 0.2 from KerbalStuff

Installation

Download, extract in the GameData folder and profit!

Features

• Added Liquid Nitrogen as a resource which can be used for Thermal/Magnetic Rockets
  
• Liquid Nitrogen can be scooped from the atmosphere
  
• Added several configuration settings including MaxThermalNozzleIsp (set to 5000)
  
• Improved Lab research : Profession & Skill now matter (+/- 50%) , effect of stupidity reduced (+/- 10%)
  

Fixes

• Fixed KSPI Legacy issue where stupid Kerbals would actually improve research output in the Lab
  
• Fixes KSPI Legacy issue where Athmospheric scoop would not reset flow to 0 when flying out of atmosphere
  

Installation

To install simply extract into Your GameData folder.

Edited January 22, 2015 by FreeThinker

[FreeThinker]

I was thinking, with the new introduction of the Nitrogen propellant, you could theoreticly use a rocket to the end of time. Which make me think how this would work realisticly. Then I found this:

One problem with solid-core NTRs is that if the propellant is corrosive, that is, if it is oxidizing or reducing, heating it up to three thousand degrees is just going to make it more reactive. Without a protective coating, the propellant will start corroding away the interior of the reactor, which will make for some real excitement when it starts dissolving the radioactive fuel rods. What's worse, a protective coating against an oxidizing chemical is worthless against a reducing chemical, which will put a crimp in your wilderness refueling. And trying to protect against both is an engineering nightmare. Oxidizing propellants include oxygen, water, and carbon dioxide, while reducing propellants include hydrogen, ammonia, and methane. Carbon Monoxide is neither, as the carbon atom has a death-grip on the oxygen atom.

source: http://www.projectrho.com/public_html/rocket/enginelist.php#lantr

With this in mind, We could introduce a oxidising/reducing coating variable/resource that limits the usage lifetime of NTR depending on the used propellant for propulsion. Also could introduce the possibility of nuclear fuel loss when it starts dissolving the radioactive fuel rods after 90% oxidised/reduced state is reached. Any thoughts?

- - - Updated - - -

Now for the balancing requests:

Can you possibly try to make magnetic nozzles useful?

The way they're balanced right now, there's always a better propulsion system than a magnetic nozzle. If that's not the definition of "Underpowered", I don't know what is.

For balancing reasons I had planned to do this anyway, I will add at least 2 global configuration settings which will allow you to modify the trust and isp of magnetic noozles. I will use it myself to help balance Interstellar with Near Future.

EDIT: Lol, I had already added a global trust modifier for Magnetic Nozzles but forgot about it. It is called GlobalMagneticNozzlePowerMaxTrustMult and its default value is 1 (KSPI default). you could set it to 1.50 to improve MagneticNozzles maximum trust by 50%

Edited January 22, 2015 by FreeThinker

[Northstar1989]

I wondered why Nitrogen it's wasn't implemented as well, I shouldn't be that hard considering it just another resource. I will look into it.

Put simply, Fractal_UK said he didn't have time. He was actually interested in adding Nitrogen as an electric and NTR propellant...

Regarging the Nitrogen called "N2", I could not find it, what I did find was:

RESOURCE_DEFINITION
{
  name = Nitrogen
  density = 0.000001251
  unitCost = 0.00000005004
  flowMode = STACK_PRIORITY_SEARCH
  transfer = PUMP
  isTweakable = True
  ksparpicon = RealFuels/Resources/ARPIcons/Nitrogen
}

That's the correct resource- and the one I *STRONGLY* advise using so that it will be compatible with RealFuels...

I'm not sure if I want to use this resource definition as propellant resource because it's density is really low. A far more conveniant/realistc method of transportation would be liquid nitrogen. According to Wikipedia Nitrogen at liquid boiling point weight 0.808 g·cm3 = 0.808 kg/L = 0.000808 ton/L. So I want to introduce the following resource:

RESOURCE_DEFINITION
{
  name = LiquidNitrogen
  density = 0.000808
  unitCost = 0.00003232
  flowMode = STACK_PRIORITY_SEARCH
  transfer = PUMP
  isTweakable = True
}

The density is really low because, like you said, it's the gaseous form of Nitrogen. However, this is the form that would probably be used in real life, as it is what the Helicon Double Layer Thruster is designed around (working models have been tested on the ground), and the basis of all Nitrogen-RCS (which RealFuels already adds). The density problem is a non-issue as RealFuels assumes tank compression of 200x (leading to an effective 20,000% utilization). You should do the same. Simply figure out the appropriate volume for a fuel tank (in liters), and multiply that number by 200 to get the appropriate Nitrogen-capacity. This is actually a low-end figure for Nitrogen compression, anyways. Some quick calculations using an online Thermodynamics calculator showed that it is EASILY possible to get as much as 800x effective compression by pressurizing to 200 atmospheres (not an unrealistic pressure level for a service module tank- it's similar to what we use for breathing Oxygen) and then cooling it to -125 degrees Celcius (by comparison, Liquid Nitrogen has to be stored at a maximum temperature of -196 degrees Celcius). Sure it's still a fairly low density for a fuel resource, but it *does* help to counteract the other problem you mentioned... ("One Resource to Rule Them All")

I found some intresting data that allows me get some meaningfull NTR data. According to the data, a 3700K NTR with Hydrogen generates 8,093 m/s. Nitrogen only produces 2,649 m/s at the same Temp. From this I conclude that the ispMultiplier should be 0.3273 !!

If LH2 is getting 8093 m/s, the Nitrogen should only be getting 2171 m/s at that temperature (based on the relative molecular masses). Of course, maybe the reactor has a slightly greater efficiency when utilizing Nitrogen for some reason (but KSP-I assumes 100% efficiency for thermal rockets, so I'd still go off the relative exhaust velocities I just mentioned). Lower ISP means higher thrust, however.

Therefore intend to use the following NTR PROPELLANT settings:

BASIC_NTR_PROPELLANT
{
    name = Nitrogen
    guiName = Nitrogen
    ispMultiplier = 0.3273
    isLFO = false
    PROPELLANT
    {
        name = LiquidNitrogen
        ratio = 1
        DrawGauge = True
    }
}

I'd suggest utilizing the relative ISP values I e-mailed you, which were calculated based on the relative molecular masses of H2 and N2 (another theory- the source you found may have assumed a *higher* exhaust temperature for Nitrogen as its boiling point is higher when stored as a cryogenic liquid, and is stored even warmer as a gas- however KSP-I doesn't normally model such effects in the ISP values...) That value for ISP is still a little too high (and also leads to too low of a thrust as a result). Honestly, high-thrust low-ISP fuels are more !FUN! anyways as you end up with a bigger, faster rocker...

Edit: Notice, that Nitrogen is actually already used in the "Haber Process" for the production of Ammonia, but it was only required to be present in the atmosphere. I have added the resource and technically everything should work already. Tomorrow I will look if it will actually works for the production of Ammonia outside an atmosphere and be used in Thermal and electrical engines (using some made up values)

Go for it! The ability to manufacture Ammonia outside the atmosphere of a planet is one of the *most important* reasons to add Nitrogen as a resource (Propulsive Fluid Accumulators are the other).

Edit: Alright, everything is working now, but I'm starting to understand why Fractal left it out, it's might be a bit overpowered as it effectively allows you unlimited gathering of propellant from Kerbin atmosphere. It would allow you to launch empty Nitrogen Tanks, collect nitrogen from an elliptic orbit and travel to any planet/moon, return to kerbin and repeat. On the other hand, it will take quite a long time to gather significant amount of propellant from the upper atmosphere to refill a nitrogen rocket

You're talking theoreticals here, but have you ever actually TRIED building a Propulsive Fluid Accumulator? (hint, I have, and it's the *exact* strategy you're describing, although real life proposals use specialized satellites whose only job is to collect the Nitrogen for greater efficiency...) It's *NOT*, I repeat *NOT* easy! PFA's are most efficient in circular (NOT elliptical) orbits in the uppermost atmosphere (above 60 km in stock), but it takes FOREVER to accumulate a significant amount of fuel at that altitude. And if you dip too low, drag QUICKLY starts pulling you down towards the planet faster than you can possibly counteract it with Nitrogen gathered from the atmosphere...

It's a *VERY* fine line you have to walk to build a successful Propulsive Fluid Accumulator. Players can and should be rewarded *greatly* for succeeding in this endeavor- especially as it's an example of a REAL proposal for ISRU that has actually been on the books for quite a few decades now here on Earth... (since the 1960's, and I must emphasize NEVER did *any* Propulsive Fluid Accumulator proposals suggest using thermal rather than electric nitrogen-propulsion...) KSP-Interstellar never shied away from real-life technologies just because they seemed overpowered (Alcubierre Warp Drives, on which the mod was founded, are a prominent example), and neither should it now. Oh, and by the way, if players utilize this strategy with RealFuels installed (if you take my advice and use the same resource stats as RealFuels to ensure compatibility), they will also have to deal with mitigating boil-off of the collected Nitrogen (though not nearly as bad as for storing Liquid Hydrogen)- which is another issue that adds difficulties to Propulsive Fluid Accumulator strategies...

Edit: I'm realy not sure if Nitrogen should be allowed as an electric propellant. For one I haven't found any data to support it is possible. Sure there is such a thing as a Helicon Double Layer Thruster but it is a different type of engine than the Electric Plasma engines in KSPI. Also for game balancing reasons it might be inadvisable because it would be too good as a the "one resource to rule them all". For now, I won't include a definition for nitrogen as electric propellant (but it would work if you added yourself). Perhaps I could introduce a Magnetic Nozzle NTR motifier to make Nitrogen more effective with Magnetic Nozzle as compensation for the lack of a true Helicon Double Layer Thruster.

I hate to pressure you, but I'm going to have to pressure you here. Propulsive Fluid Accumulators are *NOT*, I repeat *NOT* worthwhile without access to Nitrogen-electric propulsion. In fact, I'm not sure if it's even POSSIBLE to build a system that collects a greater mass of Nitrogen than it expends counteracting drag without it (so long as the Atmospheric Scoops only work inside the atmosphere, instead of just above the edge of it- an issue I have been bugging Fractal_UK to fix, since REAL atmospheric scoop proposals all involve scooping at 120-200 km: ABOVE the 100 km Karman Line...)

Helicon Double Layer Thrusters are a real-life technology that has already been *proven* to work (see the article I sent you by PM, which details numerous ground-tests of Helicon Double Layer Thrusters using Nitrogen as a propellant), and Propulsive Fluid Accumulators (the real-life strategy I want to replicate in KSP-I) are not feasible in real life (or KSP with any of the Real Solar System re-scales) without Nitrogen-electric propulsion... KSP-Interstellar has, once again, never shied away from a real technology because it seems "OP'd" (may I mention that *EXACTLY* the same criticisms could be leveled against Munar ice-mining, i.e. that it allows indefinite operations outside Kerbin?), and there's no reason to start now.

One last thought on this- Helicon Double Layer Thrusters are a type of plasma thruster, but there are indeed several different types. The KSP-Interstellar plasma thruster already models *several* different real-life plasma thrusters in one part, though, as no single real-life plasma thruster design is actually able to operate on all of the different electrical fuel types already in the mod.

Alright, you can download the patch KSPI Extended 0.2 from KerbalStuff

Download, extract in the GameData folder and profit!

Could you please, please, PLEASE add Nitrogen as an electrical propellant? The whole point of my request was to get the coding work done for Fractal_UK so he could add Nitrogen as a resource and allow players to create their own Propulsive fluid Accumulators. This simply isn't possible (or if so, is VERY marginal- and doesn't work AT ALL for Real Solar System players such as myself- I play with the Kerbin 6.4x re-scale...) without Nitrogen-electric propulsion.

The strategy of Propulsive Fluid Accumulators is essentially no more nor no less OP'd than any of the other ISRU strategies requiring ZERO input resources- such as ice mining on the Mun- and there's no reason to give this one special treatment. In fact, PFA's are *SIGNIFICANTLY* harder than Munar ice-mining, as on the Mun you can just land a really big nuclear reactor to power your ISRU plant and run it at 1000x time-warp if necessary... With PFA's, it's a *requirement* to set up a Microwave Beamed Power infrastructure or utilize some reactor with greater power-density for volume than basic fission (Fusion or Antimatter Reactors, for instance. Even Antimatter Initiated Reactors won't cut it, as they actually have a low ratio of volume, and thus induced drag in FAR, to power output- and instead opt for a lower reactor mass than fission, which doesn't help *at all* with the economics of PFA's when using FAR: where drag-power ratios are all that matter, and the mass of the satellite is completely irrelevant...), and PFA's can *only* be used at physical (up to 4x) time-warp, so Propulsive Fluid Accumulators are actually MUCH harder to set up than Munar ice-mining...

Regards,

Northstar

P.S. There's *another* MAJOR reason for utilizing nitrogen-electric propulsion for Propulsive Fluid Accumulators besides the ISP, by the way- one that you seem to actually have noticed in your discussion of thermal thruster degradation. As you'll notice in the PDF link I e-mailed you, Helicon Double Layer thrusters are not a design that allows for grid-erosion (the factor normally limiting electric propulsion engine lifespan), and have a virtually *unlimited* lifespan of use in space. The electronic systems on the craft they're attached to are likely to break down due to radiation-exposure (even if *heavily* rad-hardened) far before the Helicon Double Layer thruster, in fact...

- - - Updated - - -

[*]Added Liquid Nitrogen as a resource which can be used for Thermal/Magnetic Rockets

Please, please, please tell me you'll go back and replace that with "Nitrogen" with the values used in RealFuels in the next revision. The *LAST* thing KSP needs in more redundant resources, where 2 mods have different, incompatible names/densities for the same resource. And since this KSP-I extension has been out such a short time, now is the time to go back and fix that before people start building saves around the old resource name/density.

By the way, there's another benefit to ensuring RealFuels compatibility by using the same resource name/density (once again, you can just increase the tank capacities for Nitrogen to make up for the reduced density- Nitrogen gas is highly compressible, and 100 units of a resource at 1/100th the density are identical to 1 unit of a resource at 100x the density of the less dense version, from a player/performance standpoint. But utilizing the same resource name/density makes cross-mod compatibility possible without behind the scenes without patches...) RealFuels already allows use of Nitrogen as an RCS propellant. So if you fix the resource name/density for Nitrogen, and players utilize both the KSP-I extension and RealFuels, they'll be able to scoop RCS propellant from Kerbin's upper atmosphere rather than having to travel all the way to Eve/Laythe to collect/manufacture Ammonia to make Monopropellant... (aka. "Hydrazine" in Real Fuels)

Regards,

Northstar

Edited January 22, 2015 by Northstar1989

[Xolroc]

Several parts from KSP Interstellar have a graphical glitch in the VAB; instead of rotating when hovered over, they simply grow larger and larger. A bit of research suggests this is due to a part having more than two resources on it, and no modules; however, though all the parts that do this do have more than two resources, they also have modules representing their status as fission reactors. Adding an SAS module to one of them (simply to test) does fix the problem; I suspect it's due to the fission reactor module not showing up in the module list in the parts list... or is that also a bug?

ModuleManager reported some trouble with RealFuels and KSPI; going to try running without RealFuels to see if that fixes the problem.

EDIT: Alright, seems that was not the cause of the problem. I've somewhere to be now but I'll try running KSPI all on its own later and post results.

Edited January 22, 2015 by Xolroc