RedParadize

@Nertea Do you plan on adding He3 production/extraction? I have read that there is low He3 concentration in moon regolith. Alternatively it could be produced trough fusion.

Given the size and orientation of the ladder that seem to deploy a really huge mining rig. No idea what is its specific purpose but I like it. I like that it isn't cylindrical, I wish we had more part that. After all once in spaaaace most stuff don't need to be rocket shaped. Can we have more of cubic part?

Hi there, anyone have made a patch to add lithium production to ISRU for Near future propulsion and FFT? I think I am pretty close to figure out how Kerbalism work, not quite sure trough.

Exactly! One mode is named reaction products and the other low trust. Humm, I see two trust limiter bar when I add the engine or duplicate it... But you are right it doesn't seem to affect the heat generation. My bad, its just a display bug. Looking at config it is indeed in NFP... Seems like Kerbalism remove it. Gonna fix that on my end.

No, no pipe please! Pipe are simulated and its better that way. What I meant is that if coolant tanks use is to fill the simulated pipes (depending on how far radiators are from heat source) then having hub might be a good idea. Hub would take individual radiator simulated pipe and group them into a single one, reducing the coolant volume needed. Again, that is if that's the usage of coolant tanks.

@FreeThinker Hello. Is possible to disable the maneuver tolerance? It create some issues that are very annoying, like preventing engine to work when not in time warp. Also, some very low trust engine require the burn to start way before and after the angle threshold.

@Captain Sierra I had a bad opinion of the JP10 initially, but after few test I realized that it has the lowest operating cost for mun/minimus transfer and operation. That is if you ship your fuel from surface, (at 6.4x it cost me 80k to ship 20t to orbit). Lithium isn't currently be refined ISTU, at least with the part and mods I currently have, so its career ends more or less around Kerbin orbit. Question is if its more cost effective to invest a bit more initially and go for another, more effective engine, that will remain potent useful on the long run. I really need to install community tech tree, that would change the balance quite allot.

There is a bug where connecting/disconnecting dual mode engines result in them having both of them on, for that reason I fell under the impression that heat generation was much higher that what it is. If I may suggest, JR45 modes should be renamed to D/He3 and D/He3/H or something similar. "Low trust" have higher trust than "high trust". And lol: Thats 26%!!!!!

About coolant tanks, what would make sense is that the "pipe" going from the radiator to engine or else need to be filled as well. If that's how it work then it need to be explained and shown in editor. A nice addition would be to have pipe "hub" that merge "pipes" into a single one to reduce volume needed. That and pumps, because why not?

For coolant tanks I am not 100% sure, I do not know exactly what they do. It seem that heat goes up more slowly. Outside of that... I do not know. As fore Heat sink, well heat do go up more slowly. btw, venting the gas would be a nice thing to add to this.

@NerteaI am trying to figure out if one of my mm patch could be the cause, how much square radiator weight for you ? Oh, and where are the radiator config? Edit: nevermind, I forgot that they were in another mod.

@Nertea radiator mass(t) is divided by trust or something? If I recall correctly outside the JP-10 all the other require at least 10t of radiator, most of them much more than that. This is interesting for sure, I however was more talking about comparison between engines and not to real world. Who knows, maybe if these engine would be built the simpler fission fragment would end up be the winner in reality as well. @NHunter Thanks! I think I will give it a try.

@Nertea I have yet to figure out how to use the heat exchanger in a fashion where it is better than adding more radiator. Coolant tanks effect could be buffed a tad, just to make their effect more obvious. Heat sink could be buffed as well, it could partially solve the problem of engines that run super hot.

On my side I did not reduce heat generation, I chose the less heat intense ones or run the others at partial trottle, but I suspect some people did. Problem is... radiator are really heavy, to the point where it kill the potential of the higher isp engines. @NHunter @TBenz images and comments is pretty demonstrative about this. At some point it's just isn't worth it, specially if it isn't hyperedited to orbit. I think there is two ways to address this problem. Reduce heat on high end engines or reduce the weight of radiator. If you opt for mass reduction I would suggest to also add much larger radiators. say up to 20-50 times the size/capacity of the ones we have. Having almost a hundred parts just for the interplanetary propulsion system isn't good. X-6 Clarke remain the best interplanetary engine, regardless of the trust reduction. Running several of them at the same time outperform the most advanced engine in both trust and deltaV, and its also more cost effective. Its mainly due to difference in heat generation I think.

Welp, looks like I did not need atmospheric engine after all, Discovery can do it if I do not get too low:

I actually tested it without atmo scaling, the intake start working at a proportionally equal alt with the scaled version. I do not think that's a issue. Its just much more harder on higher scale and that's it. I managed to it with this thing: It can extract about 6300 He3 and 4200 Deuterium per dive, that isn't bad at all, but to make sense that thing need to be reused. Problem I now have is that getting out of Jool leave the plane almost out of Hydrogen. I need 8k dV to break before diving, otherwise I burn. I need to extract Hydrogen elsewhere. Bussard Particle scoop seem to pick up some hydrogen particle in Jool orbit, but from want I can see it would take many, many years to pick what I need. Probably much more than nuclear reactor lifespan. Other than that, there is the water of Laythe that I could convert, but that wont be cheap. Either way it would cost multiple millions for a marginal gain. Its cheaper to ship hydrogen from Kerbin using Fission fragment, for sure. That's weird, isn't it? Ps: Engine I used a scaled down JR20A, with the regular one the plane would most likely need to be twice as big, so it would need even Hydrogen to run.

Humm... I tried several times to harvest He3 from Jool using atmo scoop. I barely succeeded at going bellow the altitude and speed limit of scooping alive and have yet to figure out how to go back to orbit again. I do not think its possible to extract it economically, at least at 6.4 scale. Edit: I did it! I just need to get to just above the atmo and drop speed by +-9000m/s Then I could use the scooper to fill up and regain them to get back to orbit. Edit2: Sad face. Bussard Particle scoop Isn't picking up enough hydrogen to feed my Jool He3 atmospheric scoop. At any rate, reactor will run out way before I get any significant amount of Hydrogen.

@NerteaI agree with you on having architecture for specific purpose. Its not that I would wish for a one size fit all, its more about that there is no engine that cover modest size lander atm. Say you want to land on Laythe, atm the only engine that is good for that is the JR20A, that one is much more powerful and heavy than needed, so a rocket much bigger than the actual need will have to be carried to Jool orbit to do so. Maybe that type of engine can't be scaled down any further, I wonder if there would be one type that could trough. About radiation, most of fusion engines produce less radiation than fission ones. Off, they do not pose as much hazard when close to them, wherever we are talking about direct radiation or contamination. When compared to space level of radiation it isn't that much of a concern, crew needs some level of protection either way. As for when the engine run... well you need a shadow shield that's for sure.

@Nertea Looks really cool. I do not know how much engine you still plan to do, but I think a small and compact lander engine would be really nice. Ideally something that do not use hydrogen as it take allot of volume. Is it something you may do? I made one for myself using a scaled down JR20A, it use 10 lithium, 3 Helium3 and 2 deuterium, a bit like JP10 but with more Lithium. It make it compact but way too expensive to run for Kerbin launch.

Sorry, JR45 paragraph is pretty hard to read. I reformulated it several times and I could not do it right. A graph would have been far better.

No need to excuse! I have yet to figure out what are the benefit from having separated loops. My only experience with SystemHeat so far is with FFT. On some of my built I had heat stabilizing at a temperature over engine safe temp, that seemed like a proper scenario to use heat exchanger. Given your comment I guess the answer is that it should not be separated.

Then the cap might be a tad low, many of FFT engine require a dozen of them if on their own loop. Would be nice to have the possibility of patching it trough config or make bigger one.

A-134NG Casaba: Ah I see, that mean we will need a ablator container too to get over its max deltaV. Its the only engine that need both smelter and dust/atmo scoop to be refueled. I think it might be wise to buff it a bit. JP-10 Impulse: On paper it might be true, but its mass is greater than NFP engines + electric setup. It may still have a slight edge over the lower ISP ones. JR-45 Fresnel: To clarify, I rate JR15 superior in relation to its ISP/mass and not trust. Thrust above 0.5g it isn't that useful for orbital and deep space maneuver. Comparing JR15 "High trust" with JR45 on "Low trust" mode only (the same fuel mass and a playload of 40t): At 8m JR45 " low trust" mode is beaten by JR15 on sheer ISP. Stretched to 10m heat generation is equal to JR15 but deltaV is still lower. At 14m it would equal JR15 deltaV but you need 12k of extra cooling and end up equal or slightly under. At 18m it DeltaV is starting to be over. But at 18m cost, size and mass difference of the vs JR15 mean is pretty big. In my eye its hardly worth the extra launch cost. Comparing JR45 "Reaction Products" with K80, thrust might be more of a issue as K80 is pretty low on that aspect. My number will be different than yours on that as I have a mass reduction patch that affect all engine equally. With Equal fuel and including radiator, a 18m JR45 in "Reaction Products" mode have the 0.21 TWR and 37km/s DV. K80 "Reaction Products" has 0.13 TWR an 260km/s DV. K80 "Low Thrust" has 0.11 TWR an 100km/s DV. Basically it in both mode it is roughly twice more trust for JR45 at a huge DV expense. Trade off isn't worth it. A note on the two mode, given they have both different fuel type and heat generation I think its a feature that will be changed only in design stage. Making both mode use the same fuel or have similar heat generation would change that. K-80 Hammertong: I did not notice that, may I suggest changing the "Low trust" mode name to something like "Deuterium Rich"? That is a very useful mode as it divide operating cost by 1/3 at the cost of 1/2 ISP. X-6 Clarke: It would have to be a pretty big nerf before being meaningful, I fear it would kill it. I do not know how if you could do that but increasing the Enr U cost would do it too to some extent. The Engine itself should not cost much as it is really simple, but if changing Enr U cost isn't possible then maybe that would do it. If Radiation was a thing then that would put that engine in the same category as the X-2, too dangerous to be close to it. That would be the best solution. About PT and FFT, its a sound issue only, it isn't too bad.

@NerteaI trough it might help if I share my impression of FFT stuff. I have to say that I did not test them on a stock game. I play 6.4x, have plenty of mod that could interfere and I also have a patch that scale down engine weight. So take it with a grain of salt. While I have read a bit about these engine on the Atomic Rocket webpage (I love it), my comment are focused on gameplay and not scientific accuracy: A-134NG Casaba: Its really heavy, ISP and trust aren't impressive. I did not find a way to replace the burned ablator, with a 40t playload it is therefore limited to less than 50k deltaV before engine need to be changed. For that reason it doesn't compare favorably to the other FFT engine, its probably the worst in fact. JP-10 Impulse: Heat generation is really low but fall into a bracket where no radiator really fit. ISP is bad, on par with most NFP engines, if it was a tad better I could see it has its use when running in "Deuterium" mode if I had a reliable access to Lithium and Deuterium. JR-20A Ouroboros: It has its use in the high trust department, nothing that X-2 doesn't do better however. (That is if you do not roleplay radiation restriction as I do) JR-15 Discovery: It's average, if it was not of He3 cost it would be ok I guess. It doesn't stand out in any category and that's its main flaw. JR-45 Fresnel: The Higher ISP of "reaction product" cant be exploited because of the extra heat generated, "low trust" mode offer better performance as the full setup have a lower dead weight. Stretching the Engine simply isn't a option in"reaction product" mode because of its heat issue. In "low trust" mode stretching benefit is marginal because of the added weight. Tested with a 40t load, JR-15 outperform JR-45 in all its configuration. K-80 Hammertong: Much better than both JR-15 and JR-45. Even with He3 cost as it is, it is more or less on par with X-6 in term of cost effectiveness. If I were to go harvest He3 that's probably the engine I would chose. I do not see the point of the "low trust" mode, it burn the same fuel mix, have almost identical trust and much worst ISP. Was it intended to burn hydrogen as well? X-2 Heinlein: Its exactly as its description say it is. X-20 Verne: Its ok, trust is good and ISP decent. With enough fuel a pretty high deltaV can be reached, it get massive pretty quickly however. I know from experience that refining 100t of uraninite -> enriched uranium -> fission pellets take ages and massive infrastructure, even on the best spot possible, that's its main drawback. Unless if K-80 X-6 and X-9 fall into higher tech I would probably not use the X-20. It should not be the case trough, X-6 could have been made in the 60s. X-6 Clarke: Simple to use, superb ISP, reasonable heat generation and decent trust. Not being able to refuel isn't a drawback, they are small and comparatively cheap, stacking and staging is cheaper then the other engines. Alternatively, they can be brought back to KSP center pretty easily. In my eye its the best of all the FFT "low trust" long ranger. X-7 Asimov: Its good, fission particle seems to be easier to produce than pellets as you do not need as much of them. Even if X-7 can refueled but in my eye the higher total weight of the setup make it less attractive than the X-6. The "afterburning" mode big drop in ISP make it hard for me to see a scenario where it would be useful, allot of tanking need to be added and resupplying would be more complex, negating its refueling capability. My conclusion is that X-6 and JR-20A are fine as they are and cover the high trust category pretty well. X-6 and K-80 stand out on the low trust category, mostly because of their lack of or low dependence on He3. He3 cost make the other fusion engines prohibitively expensive to run. Looking at my persistant.sfs (Spectral Telescope do not detect He3?) the only place where He3 can be found is Jool atmosphere... I have difficulty imagining that it can be harvested economically, certainly not on a scale large enough to rely on. If that were to be addressed, I would say that and JR-45 would still need a buff. JR-15, its too average, I think it need to excel at something the others don't. JP-10 probably need a slight buff in ISP. A-134NG Need allot of love before being competitive.

@theJesuit It seem to not consider it unless the engine fail. If it do and you keep it running it will irradiate and kill your kerbal. I did not try to get a kerbal behind the shadow shield trough!