# [1.7.3/1.6.1/1.5.1/1.4.5/1.3.1] KSP Interstellar Extended 1.22.9 Continued Development Thread

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Freethinker,

A question about an entry in the Changelog. Version 0.7.6 says:

"Fixed Hydrolox and LiquidCO2 Propellant"

I get that the changes to Hydrolox were to adjust the fuel-ratio to 1:4, like I posted about before- but what changes did you make to the LiquidCO2 propellant?

Also, forget what I said about reducing the Thrust for Water and Ammonia, like I posted about before. I gave you some numbers to use for those before, but the numbers from Atomic Rockets may be more accurate, as I may be mis-understanding the exact effects of Hydrogen-bonding on the Thrust and ISP of Ammonia and Water...

Let's apply an equation we already know to their data on Exhaust Velocity:

Thrust = Exhaust Velocity * Mass Flow Rate

So, if we use the values for Exhaust Velocity from Atomic Rockets (I have no idea where the #'s come from, or how accurate they are, but...) and assume that Mass Flow Rate increases proportional to the Molecular Mass of each propellant (that is, the liters/minute flow-rate remains unchanged) then you get...

Ammonia

Thrust = 5101 * (17.03/2.02) = 43005

Water

Thrust = 4042 * (18.02/2.02) = 36058

Note that these are arbitrary numbers with no physical significance, but they indicate Thrust relative to LH2 (which using this equation has a Thrust value of 8093).

But we already know Hydrogen gets about 1 kN/MW, so if we convert using that we get... (note that I kept more decimal places in the calculator than I show above)

Ammonia

Thrust/MW: 5.31 kN/MW

Relative ISP: 5101/8093 = 63.03% of Hydrogen

Water

Thrust/MW: 36058/8093 = 4.46 kN/MW

Relative ISP: 4042/8093 = 49.94% of Hydrogen

This actually leads to a SIGNIFICANTLY higher Thrust/MW than currently (only around 2 kN/MW with Water using the currently-assigned ISP). But MAYBE, because due to Hydrogen Bonding the specific heat capacity is higher, these numbers assume you simply reduce the propellant flow-rate in liters/minute to compensate for this... In which case. I'm inclined to go with the latter, because it doesn't require us to do anything more than adjust the Specific Impulse for Ammonia and Water...

Anyways, the CURRENT ISPmultipliers of Water and Ammonia are VERY close to these numbers (0.4714 vs. 0.4994 for Water, identical for Ammonia) so I'm inclined to let the numbers be... Apparently Fractal_UK *gasp* went out and did research on the effects of Hydrogen-Bonding on these propellant behaviors, and in this case was much more correct than what I came up with before...

ALSO, a HUGE error in my part before.

When I was calculating the expected Thrust/MW of the Thermal Turbojets, I accidentally multiplied in "g" (standard gravity) an extra time, by forgetting to divide it out of BOTH sides of an equation. The resulting Thrust/MW was 9.80665 times higher than it should be. The Thrust/MW should only have been increased 1.109 times, rather than 10.8774 times. Apparently Fractal_UK's original Thermal Turbojet performance we rather close to reality (only slightly worse) and OVERPOWERED compared to the originally (unrealistically weak) performance of the Thermal Rockets...

Summary/Conclusions:

- Leave the ISPmultipliers, Thrust, etc. of Water and Ammonia alone

- Revert the 10.8774 times increase in Thrust/MW for the Thermal Turbojets, and only increase it by 1.109 times instead!

Regards,

Northstar

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OK, so another screw-up on my part

It appears I under-estimated the Thermal Power of the Tibmerwind 75- it had about 3750 MW of Thermal Power, not 750 MW...

I actually had to back-derive this from known ThermalPower figures for the NERVA, and some conservative approximations of the efficiency of heat-transfer and such...

The current performance (Thrust, ISP, etc.) for all our Nuclear Thermal Rockets is still correct- we just need to up-rate ThermalPower by a factor of 5, and decrease Thrust/MW by a factor of 5 as well.

Obviously, this hurts the utility of solar-powered Microwave Thermal Rockets. Otherwise, it's not the hugest issue- just one of realism, rather than balance (which remains *mostly* unchanged- it DOES mean our reactors will consume uranium 5x as fast, and require 5x the radiator-mass, though...)

Regards,

Northstar

- - - Updated - - -

I;m starting wonder why aren't we using Nuclear Engines when yjry are clearly so powerful. Is it just the fear of the capital N or something else?

Well, I *DID* mess up the Thrust/MW and total ThermalPower of the nuclear reactors. The Thrust, mass, and ISP remain the same- but the reactors *should* require 5x the current radiator-mass, and consume uranium 5x as quickly...

(Although, as I pointed out to Fractal_UK, the upgraded radiators are current under-powered: with nano-engineered graphene it's now possible to build radiators with an emissivity factor GREATER THAN 1- a feat previously thought impossible... Basically, some nano-materials can be blacker than pure black... This means, once you upgrade your radiators, they *should* radiate more power for the same temperature than they currently do...)

But, yes, it's mostly being afraid of the capital N... Fortunately, Kerbals don't seem to mind nuclear rockets...

Regards,

Northstar

Edited by Northstar1989

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I get that the changes to Hydrolox were to adjust the fuel-ratio to 1:4, like I posted about before- but what changes did you make to the LiquidCO2 propellant?

Well the LiquidCO2 fix was technically a restore, they were back to lqdCO2 again and after adjusting the Hydrolox numbers I discovered they were reverted back to their wrong name. Since nobody yet uses Co2, this little mistake should not hurt anyone.

- - - Updated - - -

The current performance (Thrust, ISP, etc.) for all our Nuclear Thermal Rockets is still correct- we just need to up-rate ThermalPower by a factor of 5, and decrease Thrust/MW by a factor of 5 as well.

Just uprate all nuclear thermal power by a factor of 5? Do you realize what the full implication are? It would also mean 5 times the waste heat generated and 5 times as much potential power generated. Also we need to increase the power of Fusion power otherwise they would be a severe a step backward. I suggest you first double check your numbers, this has quite a lot of implications...

- Leave the ISPmultipliers, Thrust, etc. of Water and Ammonia alone

I had already implemented it, but for the time being I will revert them to their ispMultiplier back to their original number and remove the thrustMultiplier. Still I think we should investigate this in more detail what the correct NTR Isp/trust Multiplier should be both positively or negatively, perhaps it's idea to ask the help of one of these guys.

Edited by FreeThinker

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I read my sources again on atomic rocket and found the following interesting data

Hydrogen gives the best exhaust velocity, but the other propellants are given in the table since a spacecraft may be forced to re-fuel on whatever working fluids are available locally (what Jerry Pournelle calls "Wilderness re-fuelling", Robert Zubrin calls "In-situ Resource Utilization", and I call "the enlisted men get to go out and shovel whatever they can find into the propellant tanks"). For thermal drives in general, and NTR-SOLID in particular, the exhaust velocity imparted to a particular propellant by a given temperature is proportional to 1 / sqrt( molar mass of propellant chemical )

have you verified all propellants?

Regarding Ammonia, I think there is something missing

the molecular mass off Amonnia is 7.031 g/mol which would translate in 1 / sqrt(7.031) = 1 / 2.64575 = 0.37713

compare this to the molecular mass of hydrogen, 2.015 88 g/mol which would translate into 1 / sqrt(2.01588) = 0.704316

now the real raw ISPmulplier (compared to hydrogen) of Ammonia = 0.37713 /0.704316 = 0,535456

now compare this with out current IspMultiplier, 0.6303, so where does the 0.1 increase ISP come from?

The exhaust velocities are larger than what one would expect given the molecular weight of the propellants because in the intense heat they break down into their components. Ammonia is nice because it breaks down into gases (Hydrogen and Nitrogen).

So basicly, we have to give Amonnia a thrustMultiplier larger than 1 which would make the effective ISP equal to 0.6303

thust difference = 1 / 0,535456 - 1 / 0.6303 = 0.281

So in order to to restore the ISP of Ammonia to 0.6303, the thrust of Amonia IspMultiplier with a IspMultiplier0,535456, would have to be multiplied by 1.281. Correct?

I think this would justify to give Ammonia both an IspMultipler and a thrustMultiplier, like Hydrolox, which effective allow it to generate more effective trust (it gains power from breaking apart into Nitrogen and Hydrogen)

This fact makes Ammonia very interesting as a propellant, especially as it's easier to store (boiling point at -38 C), and much more dense (8 times) than Hydrogen, and less complicated as Hydrolox.

Edited by FreeThinker

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OK, so another screw-up on my part

It appears I under-estimated the Thermal Power of the Tibmerwind 75- it had about 3750 MW of Thermal Power, not 750 MW...

Could you give me the exact source?

The current performance (Thrust, ISP, etc.) for all our Nuclear Thermal Rockets is still correct- we just need to up-rate ThermalPower by a factor of 5, and decrease Thrust/MW by a factor of 5 as well.

I think you are on to something

Pebble Bed

[TABLE=class: prettytable floatleft]

[TR]

[TH=colspan: 2]Pebble Bed[/TH]

[/TR]

[TR]

[TH]Thrust Power[/TH]

[TD]1.59 GW[/TD]

[/TR]

[TR]

[TH]Exhaust velocity[/TH]

[TD]9,530 m/s[/TD]

[/TR]

[TR]

[TH]Thrust[/TH]

[TD]333,617 n[/TD]

[/TR]

[TR]

[TH]Engine mass[/TH]

[TD]1.7 tonne[/TD]

[/TR]

[TR]

[TH]T/W >1.0[/TH]

[TD]yes[/TD]

[/TR]

[/TABLE]

Particle bed / nuclear thermal rocket AKA fluidized-bed, dust-bed, or rotating-bed reactor. In the particle-bed reactor, the nuclear fuel is in the form of a particulate bed through which the working fluid is pumped. This permits operation at a higher temperature than the solid-core reactor by reducing the fuel strength requirements . The core of the reactor is rotated (approximately 3000 rpm) about its longitudinal axis such that the fuel bed is centrifuged against the inner surface of a cylindrical wall through which hydrogen gas is injected. This rotating bed reactor has the advantage that the radioactive particle core can be dumped at the end of an operational cycle and recharged prior to a subsequent burn, thus eliminating the need for decay heat removal, minimizing shielding requirements, and simplifying maintenance and refurbishment operations.

LANTR

Above Particle Bed produce at least 1590 MW and has a mass of 1.7 ton and produces about 330kN thrust = 194 kN / ton

Our Current KSPI Extended Particle Bed (Mk2) produces 187.5 MW and has a mass 1.2 ton (including noozle) and produces about 210kN thrust = 175 kN / ton (but can also connect to a electric generator and use LOX).

At about the same weight level our Particle Bed would have to produce produce 1590 MW / (1.5 x 187.5) = 1590 / 281.25 = 5.6 times as much as it does now. It seems your factor of 5 is conservative for Particle Bed. But what about the other nuclear reactors?

Another interesting fact is that the the reactor for operation require power the drum move at 3000 rpm! That should require significant amount of power! What happens if drum isn't active, will it fail to function, or overheat and meltdown?

Edited by FreeThinker

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Could you give me the exact source?

The calculation was a quick-and-dirty derivation (using some of the equations I've already discussed) from the known figure of 0.3 kN/MW at 850 seconds ISP for the NERVA reactor, as found on the Wikipedia page on NTR's:

http://en.wikipedia.org/wiki/Nuclear_thermal_rocket

I think you are on to something

Atomic Rockets gives us something to work off of, and check our assumptions against. And since they are close enough for reason to the real figures, if you want to balance against the lower TWR listed on Atomic Rockets, that's OK with me... It would actually still require a slight buff of our Thrust/ton to match the figure from Atomic Rockets- I don't think we should shrug off the difference, since the figures on Atomic Rockets are already quite conservative here- but seek to match those numbers as closely as possible...

Above Particle Bed produce at least 1590 MW and has a mass of 1.7 ton and produces about 330kN thrust = 194 kN / ton

Our Current KSPI Extended Particle Bed (Mk2) produces 187.5 MW and has a mass 1.2 ton (including noozle) and produces about 210kN thrust = 175 kN / ton (but can also connect to a electric generator and use LOX).

It seems the figures on Atomic Rockets are decent. They may not precisely match up with any figures I know of (for instance, the Thrust figure they give for a Particle Bed Reactor is somewhat less even than the Timberwind 45, and their TWR is closer to 20 rather than the known figure of 30 for a Timberwind Particle Bed Reactor... A Timberwind 75 produced 294.2 kN/ton, at a mass of 2.5 tons according to Wikipedia and Encyclopedia Astronautica...)

So far, our TWR has been lower because we did not reduce mass to 1/4th the Timberwind 75 we were balancing against. We got a bit closer with the new version you created for TweakScale, but the accurate mass for a reactor of that size would be only 0.625 tons... You justified the mass-difference with shielding requirements, etc., even though I am fairly sure Timberwind 75 already included these in its original mass figure...

At about the same weight level our Particle Bed would have to produce produce 1590 MW / (1.5 x 187.5) = 1590 / 281.25 = 5.6 times as much as it does now. It seems your factor of 5 is conservative for Particle Bed. But what about the other nuclear reactors?

The Particle Bed Reactor listed on Atomic Rockets produces (333.617 / 1590) = 0.2098 kN/MW, which is *almost exactly* the figure I got from my quick-and-dirty calculation of what your Thrust/MW *should* be before... Of course, their figure is assuming an ISP of 966.5 seconds, whereas mine assumes an ISP of 1000 seconds... (this is before the 15% increase to Thrust/MW and Vacuum ISP we assume from having a very large nozzle...)

Another interesting fact is that the the reactor for operation require power the drum move at 3000 rpm! That should require significant amount of power! What happens if drum isn't active, will it fail to function, or overheat and meltdown?

As I understand it, the centrifugal action is actually driven by the LH2 flow through the reactor. There's no mention of an external power source or electric generator/motor combination *anywhere* in any of the articles of particle bed reactors I could find, and there are some statements in the design documents of Timberwind that led me to believe something along those lines might be occurring (I didn't mention it before because it should have no bearing on Thrust/Mw or ISP performance...)

There is motion that occurs, but an object in motion remains in motion unless acted on by an outside force- which would only be friction in this case (which would just convert that kinetic energy back into Thermal Energy- precisely the thing we want out of the reactor in the first place!)

OK, so anyways, this gives us some good figures on the Thrust/MW to use for Hydrogen (their figures are conservative enough I believe we should stick to an Exhaust velocity of 1000 seconds, and their figure for Exhaust Velocity seems to assume a rather smaller nozzle- so I think we should stick with the extra 15% Vacuum ISP and Thrust/MW on top of that for the large nozzles we've been using...)

Based on the figures from Atomic Rockets, I would suggest an even more conservative 6x increase in ThermalPower and 1/6th decrease in Thrust/MW. The Thrust of our NTR's shouldn't change, just the amounts of ThermalPower (and thus uranium-consumption and WasteHeat generation) that go into generating that performance...

I am *still* a fan of reducing the reactor mass to get a more realistic Thrust/ton (unless you want to increase the Thrust production without increasing reactor mass, and stick with the current figure). Our current figures is, as I've repeatedly stated, too low- and leads to an even lower TWR than the one stated on Atomic Rockets, which is itself a very conservative number...

Also, the Thrust/MW of our Thermal Turbojets needs to be decreased by the same factor (5-6x) as that of our Thermal Rockets.

Note, though, that this is *AFTER* the 1.109-fold increase in Thrust/MW, for a *net* decrease to only .2218 - .185 times the original Thrust/MW as implemented by Fractal_UK (which, with a 5-6x increase in our current ThermalPower from reactors, which is built on an already-significant increase to reach the 187.5 MW number for a Sethlans we moved to before, *still* equates to a significantly higher overall Thrust for a Thermal Turbojet attached to the same reactor than in the original release... So, a *nerf* to the Thrust/MW of the original TTJ is necessary to still obtain realistic performance with a much higher ThermalPower production by all reactors...)

Regards,

Northstar

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Well the LiquidCO2 fix was technically a restore, they were back to lqdCO2 again and after adjusting the Hydrolox numbers I discovered they were reverted back to their wrong name. Since nobody yet uses Co2, this little mistake should not hurt anyone.

Thanks for catching that- otherwise it would have created some headaches for me, wondering what happened to the name-fix I wrote up before (and had already been implemented...)

Just uprate all nuclear thermal power by a factor of 5? Do you realize what the full implication are? It would also mean 5 times the waste heat generated and 5 times as much potential power generated.

Affirmative. All these effects are both desired and realistic. The fuel-consumption would be increased 5-fold as well. It seems nothing in this world is without a cost or drawback...

I don't think the Fusion reactors *should* be buffed, as they were currently producing far too much surplus ThermalPower beyond what is needed to maintain the magnetic confinement fields compared to what we can expect form Fusion any time in the next 200 years in real life... In fact, I'm not sure you really will like what I think should be done to the Fusion reactors, but I'll tell you anyways...

Technically I *do* think they should have their ThermalPower increased- their ThermalPower production should be increased, and the electrical power required to maintain the magnetic confinement should be increased by almost the same amount- which would effectively *nerf* the Fusion reactors, as they would produce the less surplus ThermalPower than before (because there is inefficiency in converting ThermalPower into electrical power), but now require even more radiator mass to deal with all the WasteHeat produced...

This would make for a *more realistic* implementation of Fusion Reactors- and would make having an upgraded electrical generator a practical necessity in order to get any useful amount of surplus power out of them (due to the need to convert very large amounts of ThermalPower into electrical power just to maintain the magnetic confinement field- which is what would limit their utility in real life more than anything else... All that electrical power production, and very high total ThermalPower production that mostly needs to be cycled back into electrical power, results in the need for *VERY* large radiators to get much use out of a Fusion reactor in space...)

Also we need to increase the power of Fusion power otherwise they would be a severe a step backward. I suggest you first double check your numbers, this has quite a lot of implications...

Fusion reactors *do* need a large nerf if you're aiming for realism. If you ask me, we should apply the same 5-6x increase in ThermalPower production, but increase their magnetic confinement electrical power requirements roughly 50-fold from what they are now (a measly 5 MW for a small reactor). THEN you would start to see a more realistic implementation of fusion power...

I had already implemented it, but for the time being I will revert them to their ispMultiplier back to their original number and remove the thrustMultiplier. Still I think we should investigate this in more detail what the correct NTR Isp/trust Multiplier should be both positively or negatively, perhaps it's idea to ask the help of one of these guys.

Well, we already have good data on what the ISPmultiplier should be from that Atomic Rockets chart. It just seems Fractal_UK already had the correct #'s for this in the first place...

What did you mean about removing the Thrustmultiplier, though? I hope you didn't remove the Thrustmultiplier from the Thermal Rockets entirely- the *original* performance way back when (in Fractal_UK's original version) was something like 0.1 kN/MW, whereas we want 0.2 kN/MW based on the Atomic Rockets figures...

Ultimately, we had the right numbers for Thrust and ISP (for Hydrogen)- we just need to adjust the Thrust/MW, reactor mass (still too heavy, but we already knew that...) and ThermalPower production to match...

As for Ammonia, Water, etc. and the other fuel-modes, once we have the correct Thrust/MW implemented for Hydrogen and the correct ISPmultiplier for all the other fuels, Fractal_UK's coding for determining Thrust should be more than capable of figuring out the correct Thrust/MW for all the other fuels.

The only thing we will need to adjust is for fuels that undergo a chemical reaction in addition to the heating- such as LOX-augmentation of Hydrogen or Methane (which, for Hydrogen LOX-augmentation, approximately triples the Thrust *relative to Hydrogen alone*) or the breakdown of Ammonia into N2 and H2 (2 NH3 --> N2 + 3 H3) which according to the Ideal Gas LAW (PV = nRT) should approximately double the Exhaust Pressure (and thus the Thrust/MW) of Ammonia for its Exhaust Velocity... Be careful that the last one (Ammonia) is implemented properly- because what it should look like is doubling both the Thrust and fuel-consumption from the coding side of things... (i.e. the ISP remains unchanged)

I never object to asking for help, though. Feel free to go and do that if you want!

Regards,

Northstar

P.S. I'm aware that increase the reactor's ThermalPower production would, indirectly, also improve the viability of Nuclear-Electric propulsion (using a nuclear reactor to power plasma thrusters). This is both realistic and desired- nothing about our Plasma Thrust ISP or Thrust/MW was based on the Thermal Rockets. In fact, the only changes we've made to them so far was to actualize a realistic relationship between Vacuum ISP and Sea-Level ISP for them, and to implement new fuel-modes for them such as CO2 and N2...

Edited by Northstar1989

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Also, EMPeror raised an interesting point:

http://en.wikipedia.org/wiki/Water_splitting

At 3000C, 50% of the water will be disassociated. Does this come into play?

3000 Celsisus is 3273.15 Kelvin, which is about the temperature our Molten Salt Reactors operate at (3200 K). With 50% splitting of water into 1.5 particles each (2 H2O --> 2 H2 + O2) you get a 25% increase in Exhaust Pressure- and thus, Thrust. However the MSR's are a *but* colder than that, so only a 20-24% increase in Thrust when using Water is probably in order...

This does get to the heart of a major issue, though- several fuels we currently use break down into multiple particles when heated to the temperatures of a Thermal Rocket.

Ammonia will do it for pretty much any of our Thermal Rockets (Microwave Thermal, Nuclear Fission Thermal, Fusion Thermal, etc.), and will double your Thrust when it does... (as you double the moles of gas and thus Exhaust Pressure)

But Water requires such a high enough temperature that you need something at least 3200 K (the temperature of our Molten Salt Reactors, but not the optimal temp. of our Pebble Bed Reactors- which operate optimally at 3000 K) to do it to just 50% of the Water- which means it won't affect our Microwave Thermal Rockets at all (too cold), and won't affect our Pebble Bed Reactors unless they're running at sub-optimal temperature with the Mk2 version (since you implemented a Mk1 "experimental" version that operates at the same temperatures as Fractal_UK's original part...) And, when Water is breaking down 100% instead of only half (such as at the temperatures of a Fusion or Antimatter Reactor) Thrust will increase 50% instead of 25%...

A side note: LOX-augmentation normally occurs in the NOZZLE of a nuclear thermal rocket, after the gasses have already greatly cooled off due to their expansion in the nozzle (exhaust gasses lose pressure and temperature, but gain velocity, in a rocket nozzle). So, you can still have LOX-augmentation in the nozzle even if the reactor is hot enough to break water into LH2 + LOX...

Oh and Methane? It will start to gook up the reactor with graphite-formation through pyrolysis (CH4 --> C (solid) + 2 H2) if it gets hot enough (I have NO IDEA what temperatures would have to be reached for this to happen- although the fusion and antimatter reactors would certainly get hot enough...), although the increase in Exhaust Pressure from the doubling of moles of gas will also *temporarily* double your thrust until the reactor-gooking catches up with you...

I have *no idea* how to implement a temperature-dependent Thrust increase like this- although I might try looking at the Particle Bed Reactor code for some clues, since it already allows players to increase its temperature by decreasing WasteHeat removal, and has to change its Thrust/MW and ISP as a result of its variable exhaust temperature...

Regards,

Northstar

Edited by Northstar1989

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FreeThinker,

Also, I know I've been throwing out a lot of information at once, but we still need to implement the code I presented in this post and the one above it to fix the ISRU refinery tanks so they are insulated and customizable with RealFuels, and so the harvestable (trace) Oxygen resource in Duna's atmosphere becomes LOX instead of "Oxidizer"...

Here's the code that needs to be added to the RealFuelsFix file again, for your convenience. Note that the Duna atmospheric resource definition MM patch needs to be buried at the same layer as the other atmospheric resource definition patches, or needs its own header (which is NOT included here) or else it won't work...

`//Make ISRU refinery tanks insulated and modular@PART[FNRefinery]:FOR[RealFuels]{	MODULE	{		name = ModuleFuelTanks		volume = 1750		type = Cryogenic	}}@PART[FNInlineRefinery]:FOR[RealFuels]{	MODULE	{		name = ModuleFuelTanks		volume = 1750		type = Cryogenic	}}@PART[FNInlineRefineryLarge]:FOR[RealFuels]{	MODULE	{		name = ModuleFuelTanks		volume = 11000		type = Cryogenic	}}`

See my earlier post for where in the file this second piece of code goes...

`    @ATMOSPHERIC_RESOURCE_DEFINITION[DunaOxygen]     {        resourceName = LqdOxygen    }`

Also, I mentioned a couple ISRU processes to turn CO2 into O2 and produce either CO or solid Carbon as a waste-product... We eventually want to get those implemented, as well as the ability to use the CO2 resource for the Sabatier Process (if that was implemented, it doesn't show up in the Changelog, at least) and some of the other ISRU processes (like Hydrogen Peroxide production from Hydrogen and Oxygen instead of Oxygen and Water) that I mentioned before...

Regards,

Northstar

Edited by Northstar1989

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I don't think the Fusion reactors *should* be buffed, as they were currently producing far too much surplus ThermalPower beyond what is needed to maintain the magnetic confinement fields compared to what we can expect form Fusion any time in the next 200 years in real life... In fact, I'm not sure you really will like what I think should be done to the Fusion reactors, but I'll tell you anyways...

Technically I *do* think they should have their ThermalPower increased- their ThermalPower production should be increased, and the electrical power required to maintain the magnetic confinement should be increased by almost the same amount- which would effectively *nerf* the Fusion reactors, as they would produce the less surplus ThermalPower than before (because there is inefficiency in converting ThermalPower into electrical power), but now require even more radiator mass to deal with all the WasteHeat produced...

This would make for a *more realistic* implementation of Fusion Reactors- and would make having an upgraded electrical generator a practical necessity in order to get any useful amount of surplus power out of them (due to the need to convert very large amounts of ThermalPower into electrical power just to maintain the magnetic confinement field- which is what would limit their utility in real life more than anything else... All that electrical power production, and very high total ThermalPower production that mostly needs to be cycled back into electrical power, results in the need for *VERY* large radiators to get much use out of a Fusion reactor in space...)

That would effectively turn the Fusion reactor into a very high temperature oven, barely capable of producing more power than it consumes. but perfect if you want to achieve high Isp Thermal Thruster or use it to generate even higher Isp from magnetic noozles. Regarding, magnetic nozzles, what should be their Isp? I bet you could get some pretty high Isp from those fusion fed magnetic noozles.

- - - Updated - - -

Affirmative. All these effects are both desired and realistic. The fuel-consumption would be increased 5-fold as well. It seems nothing in this world is without a cost or drawback...

Well, there are a few parameters we can tweak to compensate, one of them is minimal utilization, original it was set to 25% for kiwi, but I want to set it to 10% (already did) this will make the molten salt core reactor maintain it reliable stand by functionality. I can also give it more fuel and as a last option I might increase the fuel efficiency.

- - - Updated - - -

But Water requires such a high enough temperature that you need something at least 3200 K (the temperature of our Molten Salt Reactors, but not the optimal temp. of our Pebble Bed Reactors- which operate optimally at 3000 K) to do it to just 50% of the Water- which means it won't affect our Microwave Thermal Rockets at all (too cold), and won't affect our Pebble Bed Reactors unless they're running at sub-optimal temperature with the Mk2 version (since you implemented a Mk1 "experimental" version that operates at the same temperatures as Fractal_UK's original part...) And, when Water is breaking down 100% instead of only half (such as at the temperatures of a Fusion or Antimatter Reactor) Thrust will increase 50% instead of 25%...

Ok, so Water does break down, then I guess atomic rockets was wrong when they said

Water is most unhelpful since it doesn't break down much at all.

I think I can easily implement the breaking down at certian temperature , give me a minimum temperature and maximum temperature where you recieve maximum trust bonus, I can implement is as a simple linear function.

For example at 2200 Ã‚Â°C about three percent of all H2O molecules are dissociated into various combinations of hydrogen and oxygen atoms, mostly H, H2, O, O2, and OH. Other reaction products like H2O2 or HO2 remain minor. At the very high temperature of 3000 Ã‚Â°C more than half of the water molecules are decomposed,

So it start at 2200 and at 3000 more of half is decomposed ? What about a simple liniar function: factor = Min(Max((temperature - 2200)/ 1600, 1),0)

Edited by FreeThinker

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Just tried installing the extension and noticed the generators wouldn't work connected up to the reactors. I had a stack which was module -> small reactor -> generator -> radiator. The generators temperature was increasing but its power output stayed at 0.0 kw/e. Also swap fuels didn't work with the small reactor. I get the feeling I've stuffed up something when doing the install but can't figure out what.

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Just tried installing the extension and noticed the generators wouldn't work connected up to the reactors. I had a stack which was module -> small reactor -> generator -> radiator. The generators temperature was increasing but its power output stayed at 0.0 kw/e. Also swap fuels didn't work with the small reactor. I get the feeling I've stuffed up something when doing the install but can't figure out what.

Woo.. ok got the power generator going. Must have not clicked the "overwrite" button during the install. Still can't swap to ThF4 though.

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Woo.. ok got the power generator going. Must have not clicked the "overwrite" button during the install. Still can't swap to ThF4 though.

That's a feature, ThF4 is the fuel for the Gas Core Reactor. The molten Salt reactor now produces much more power than in the past

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Oh and Methane? It will start to gook up the reactor with graphite-formation through pyrolysis (CH4 --> C (solid) + 2 H2) if it gets hot enough (I have NO IDEA what temperatures would have to be reached for this to happen- although the fusion and antimatter reactors would certainly get hot enough...), although the increase in Exhaust Pressure from the doubling of moles of gas will also *temporarily* double your thrust until the reactor-gooking catches up with you...

Yes, I might implement it using non tranferable resource Sut (Carbon) which would slowly accumulate using methane. The question is how should it affect the reactor. For example, Would it clog the noozle, effectively slowing reducing maximum trust /isp up to a maximum?

Another thing, what about using Alcohol as a propellant. I heard the russians used it in the early days for they nuclear engines. Any idea of it's ISP and trust effects with high temperature?

Another thing that I wonder is, "would using hydrogen in a atmosphere with oxygen (like on earth) have any effect when using any flamable gas/liquid (like hydrogen/methane/alcohol)?"

Edited by FreeThinker

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Northstar1989, FreeThinker,

while I greatly appreciate the work you are doing on KSPI, please reconsider the direction you are taking this mod.

With Fractal_UK and Boris-Barboris both not actively working on KSPI you are essentially the only game in town for this mod.

The changes you are implementing base all values off of real-world mechanics without considering the gameplay at all.

From my perspective it almost looks like you are holding KSPI hostage to force people into RSS/RO.

While RSS/RO might be very interesting for realism oriented players, it is still a fringe community inside KSP and the target audience for KSPI is quite a bit larger than that. Especially considering that RSS/RO has the potential to break a lot of other mods or require extensive work to ensure compatibility.

In my opinion an extensive mod like KSPI should work from the assumption that it's the only active mod (including necessary dependencies ofc) in an otherwise stock KSP install. Balance the mod against stock KSP and deal with rebalancing mods vie MM-patches, configs, etc.

Please don't take this mod away from the greater KSP community.

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Northstar1989, FreeThinker,

while I greatly appreciate the work you are doing on KSPI, please reconsider the direction you are taking this mod.

With Fractal_UK and Boris-Barboris both not actively working on KSPI you are essentially the only game in town for this mod.

The changes you are implementing base all values off of real-world mechanics without considering the gameplay at all.

From my perspective it almost looks like you are holding KSPI hostage to force people into RSS/RO.

While RSS/RO might be very interesting for realism oriented players, it is still a fringe community inside KSP and the target audience for KSPI is quite a bit larger than that. Especially considering that RSS/RO has the potential to break a lot of other mods or require extensive work to ensure compatibility.

In my opinion an extensive mod like KSPI should work from the assumption that it's the only active mod (including necessary dependencies ofc) in an otherwise stock KSP install. Balance the mod against stock KSP and deal with rebalancing mods vie MM-patches, configs, etc..

Well that what KSPI NF Integration is for. KSP Integerstelar never matched well with stock engines. KSPI produced Gigawatt is in no comparison at all with the kilowatts produced/required by KSP stock, or the megawatt produced/required by Near future reactors. Soon will I upload a full download which will allowtweaking Ksp Extended to fit better with Stock. Ksp NF integegration will do exactly this, which will tweak Ksp Extended to play nice with stock Ksp.

Edited by sal_vager

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Well that what KSPI NF Integration is for. KSP Integerstelar never matched well with stock engines. KSPI produced Gigawatt is in no comparison at all with the kilowatts produced/required by KSP stock, or the megawatt produced/required by Near future reactors. Soon will I upload a full download which will allowtweaking Ksp Extended to fit better with Stock. Ksp NF integegration will do exactly this, which will tweak Ksp Extended to play nice with stock Ksp.

That looks to me like users will have the choice between either a seriously nerfed KSPI (to get in line with NF) or a serioudly overpowered KSPI (to get in line with RSS/RO). Where's the middle ground?

I always found NF to be quite underwhelming in terms of power/price it offered, while the "old" KSPI hit a sweet spot for me. You got seriously powerful system as a very late game option and it's MegaJoule mechanic made it mostly self contained. (The GW of power didn't really come into play since it sidestepped the Ec mechanic.) You paid for all this power in gameplay (AM harvesting, lots of science) instead of partcount (bad, causes slowdowns) or weight (translates to partcount).

The changes you and Northstar1989 are implementing make KSPI-E seriously overpowered to the point of being cheaty in stock KSP while KSPI-NF seems to "drag down" KSPI to NF's performance level (or slightly above).

And now to something completely different:

Boris-Barboris' KSPI for 0.90 came together with a TweakScale Fix that has since been pulled by the mods. So far I worked around this by removing TweakScale configs for all the air intakes.

What's the situation right now? (My save is still on KSPI-E 0.6.1) If I reinstall KSPI-0.90 and over that KSPI-E do I need to do something to TweakScale? Has the problem been fixed?

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That would effectively turn the Fusion reactor into a very high temperature oven, barely capable of producing more power than it consumes. but perfect if you want to achieve high Isp

That's pretty basically correct for how a first-generation fusion reactor should behave. The really high net ThermalPower production levels should come from upgraded versions...

Thermal Thruster or use it to generate even higher Isp from magnetic noozles. Regarding, magnetic nozzles, what should be their Isp? I bet you could get some pretty high Isp from those fusion fed magnetic noozles.

With temperatures of "millions" of degrees, the ChargedParticles could *easily* yield an ISP of 50,000 seconds or more. This is a propulsion system that you could use for *INTERSTELLAR* travel due to the mass-fractions it allows...

Well, there are a few parameters we can tweak to compensate, one of them is minimal utilization, original it was set to 25% for kiwi, but I want to set it to 10% (already did) this will make the molten salt core reactor maintain it reliable stand by functionality. I can also give it more fuel and as a last option I might increase the fuel efficiency.

All sound great to me... I never understood why the reactors had to operate at 25% standby power anyways...

Ok, so Water does break down, then I guess atomic rockets was wrong when they said

I think I can easily implement the breaking down at certian temperature , give me a minimum temperature and maximum temperature where you recieve maximum trust bonus, I can implement is as a simple linear function.

So it start at 2200 and at 3000 more of half is decomposed ? What about a simple liniar function: factor = Min(Max((temperature - 2200)/ 1600, 1),0)

Looks like a good solution to me! Don't forget Ammonia ALWAYS breaks down in a 1:2 molar ratio (1 mole of ammonia --> 2 moles of Nitrogen and Hydrogen gasses) at the relevant ThermalRocket temperatures- so it should have pretty much double the Thrust/MW you would expect for its ISP as well...

Regards,

Northstar

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It is a bit silly to argue over the integration and KW/GW of power. In all instances, a technological increase is exponential it seems. It's never suppose to be "balanced", it's suppose to be a replacement/upgrade. Or would you consider it reasonable to balance carrier pigeon to meed the bandwidth of fibre internet? No. So why worry about balancing the NF and IS engines to match each other? They are suppose to be Steam to Petrol, or Gas to Nuclear in a gap of performance.

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It is a bit silly to argue over the integration and KW/GW of power. In all instances, a technological increase is exponential it seems. It's never suppose to be "balanced", it's suppose to be a replacement/upgrade. Or would you consider it reasonable to balance carrier pigeon to meed the bandwidth of fibre internet? No. So why worry about balancing the NF and IS engines to match each other? They are suppose to be Steam to Petrol, or Gas to Nuclear in a gap of performance.

Well note that that they do share the same names for parts. they both have plasma thrusters except in NF they require >100 times less power!! In NF, at most you could run 2 plasma thruster on 1.25 nuclear reacor, with a IS 0.625 reactor you can more than 10 NF plasma thrusters.. Anywhay, for further discussion continue here

- - - Updated - - -

And now to something completely different:

Boris-Barboris' KSPI for 0.90 came together with a TweakScale Fix that has since been pulled by the mods. So far I worked around this by removing TweakScale configs for all the air intakes.

What's the situation right now? (My save is still on KSPI-E 0.6.1) If I reinstall KSPI-0.90 and over that KSPI-E do I need to do something to TweakScale? Has the problem been fixed?

Well I used this fixed in the past and it game me more trouble than it is worth. I switched back to 1.5 for now, but I'm hoping freescale will replace it.

Edited by FreeThinker

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Northstar1989, FreeThinker,

while I greatly appreciate the work you are doing on KSPI, please reconsider the direction you are taking this mod.

I'm listening...

With Fractal_UK and Boris-Barboris both not actively working on KSPI you are essentially the only game in town for this mod.

The changes you are implementing base all values off of real-world mechanics without considering the gameplay at all.

We're basing values off real-world mechanics for the same reason Squad is finally taking a more realistic approach to its aerodynamics system- because real life provides an inherently intuitive and balanced solution on how to model+code things...

The performance for *almost EVERYTHING* is receiving a substantial buff with the more realistic values, from Thermal Rockets (which are getting better Thrust) to plasma thrusters (which are gaining the ability to operate off propellants you can scoop from the edge of atmospheres and drive Propulsive Fluid Accumulators)...

From my perspective it almost looks like you are holding KSPI hostage to force people into RSS/RO.[

To be honest, that's never been a strain of logic I understood very well. How could *improving* the performance of parts to match real-world specifications hold people hostage to RSS/RO-like gameplay.

As far as I can tell, the only way to hold people hostage to RSS/RO-like gameplay is to actually force them to install RSS or RO (which I would never do). Having better part performance makes the game easier, and actually makes the game *less* restrictive in terms of what you can build and what you can do- which is the opposite of what RSS/RO tends to do to players (where the high Delta-V requirements force more optimal/ well-engineered spacecraft designs...) Having better part performance actually moves things *away* from restricted gameplay- and moderates the difficulty even if you have RSS/RO installed...

While RSS/RO might be very interesting for realism oriented players, it is still a fringe community inside KSP and the target audience for KSPI is quite a bit larger than that. Especially considering that RSS/RO has the potential to break a lot of other mods or require extensive work to ensure compatibility.

Nothing about this work on furthering KSP-Interstellar forces or even suggests to players that they use Real Solar System or Realism Overhaul. I especially wish you'd stop saying it encourages Realism Overhaul- because personally even I don't play with that mod and wouldn't touch it with a 20-yard stick... (because I have no desire to play a 100% scale solar system in a game engine with as many inherent limitations as KSP...)

In my opinion an extensive mod like KSPI should work from the assumption that it's the only active mod (including necessary dependencies ofc) in an otherwise stock KSP install. Balance the mod against stock KSP and deal with rebalancing mods vie MM-patches, configs, etc.

KSP-Interstellar was *always* balanced against real life, to a certain degree. The mod has long had a reputation for being "overpowered", even compared to real life- simply because players did not understand that real rockets simply perform a lot better than what they're used to in KSP, and Interstellar has always leaned in the "realism" rather than the "gamey" direction. That being said, you'll find that most of the re-balances improve the fun of gameplay. Where else can find a nuclear thermal rocket you can use as a LAUNCH ENGINE? (like the real world Timberwind design we balanced the Particle Bed Reactors against was meant to do)

KSP-Interstellar fundamentally exists to allow players to do thing MUCH more powerful than they could do in the stock game, but that are or might someday be possible in real life. Warp-drives, for instance: which were the only feature the mod was originally released with back in the day...

You're free to play with parts as futuristic or near-term as you like. Personally, I never play with anything much beyond first-generation fission reactors and Microwave Thermal Power- and a 1st generation fusion reactor here and there if I'm feeling REALLY adventurous... Nothing about KSP-Interstellar forces you to play with any mods that add extra difficulty (like Real Solar System or RealFuels- although I strongly recommend the latter with the new aerodynamics system that will be coming out anyways, as it allows you to build MUCH more stable rockets by playing with the fuel-density and mass-distribution of different stages...) but you can always impose your own limitations if you wish.

Oh yeah, and if you still want performance in the range of the original parts- play with the Community Tech Tree. The "Mk1" first-generation fission reactors still have performance highly similar to the original balance, whereas it's not until the "Mk2" parts that you start to see realistic performance. The "Mk1" parts are also available at an earlier tech-node as I understand it, although I've never actually played with Community Tech Tree...

Please don't take this mod away from the greater KSP community.

How are we taking anything away by *adding to* the mod? All the original parts with the balance you know and love are still there with the "Mk1" or "experimental" versions of each reactor (maybe FreeThinker was onto something by leaving them in there- I wanted to remove them entirely). We're just adding essentially a new upgrade-level with more realistic performance. Changes like raising the Thrust/MW of the Thermal Rocket Nozzles do improve the performance of the "experimental" parts, but only a little.

Regards,

Northstar

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JUst FYI, Boris-Barboris is back on the forums

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That looks to me like users will have the choice between either a seriously nerfed KSPI (to get in line with NF) or a serioudly overpowered KSPI (to get in line with RSS/RO). Where's the middle ground?

nerving is not the correct word here because some parts, (mainly the electric engines) are made more powerful while the thermal thrusters will perform between stock nuclear engines and kspi extended thermal noozles. Note that KSPI clasic, thermal noozles were significantly weaker than stock nuclear engines, and didn't become better late game.

Edited by FreeThinker

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Hey FreeThinker,

Since you're currently checking this thread, don't forget about the code-changes to the RealFuelsFix file (KSP-I/RealFuels compatibility file) I posted here.

Regards,

Northstar

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Since you're currently checking this thread, don't forget about the code-changes to the RealFuelsFix file (KSP-I/RealFuels compatibility file) I posted here.

I had already implemented them, I even posted them in the realfuels tread, I simply forgot to add the to the patch folder. so don't worry.

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