YourLocalMadScientist

Right diagnosis, wrong treatment I'm afraid. The Tri-alpha still outputs at full power, all going into waste heat. I did a few more tests, and i found the problem never exists when there is only one reactor. It tends to occur when there are multiple reactors, as it will add up values weirdly. The craft is meant to have 2*3.65GW PJMIFR Reactors + 1*0.340GW TAFR, + 1*0.6GW MTFR + 1*0.006GW MSR. Somehow, it is adding that all up and getting 26GW of waste heat. It is clearly doing something weired in terms of how the waste heat is being added up when there are multiple reactors. I noticed that you changed the PJMFT to not permit various propellant types to be used in an attached thermal nozzle. I changed it back as it would mean most of the flights in my save-game are now useless. Furthermore, as it's burning a D-T fuel, most of the energy from the fusion reaction will still be in the form of neutrons. If the reactor is to be used as a thermal source, then it should be possible to allow those neutrons to pass through some low-capture-cross section pipework, and directly heat the propellant (the engineering details are left as an exercise for the reader). There isn't really much reason to suggest such a reactor couldn't be used to heat a working fluid, and if that's the case, it could run on any of the fluids that the other engines could run on (although the effective temperature would be somewhat lower than the optimistic 50000K). Now, if the primary consideration of this change is purely game-play based, physics be damned, then that is a different matter. If this reactor is meant to be a dedicated charged particle producer, then i would suggest updating it's description, or possibly giving it access to aneutronic fuels at an earlier stage in the tech tree, otherwise it wouldn't have much use. This all really depends on what you see as the niche that this reactor is meant to fill.

Firstly, @FreeThinker thank you for continuing to work on this most excellent mod. I know it's a pain when updates break everything, but I hope you are able to continue working on it. However, I feel compelled to bump the "waste heat" issue that people have been reporting since 1.15.1.8 (I think). At the moment, any craft I have that relies on thermal propulsion powered by an on-board reactor will overheat in a matter of seconds. Screenshots: This is a very clear bug, as the craft has 3.8GW generating capacity, and is running a thermal engine consuming 3GW (537.2E3N*(9.8*797.2s)/2=2098GW propulsive power), but is increasing it's waste heat amount by 2.78GW, which is a clear violation of conservation of energy. It looks like this is some kind of double counting error where the energy from the reactor is both powering the engine AND contributing to waste-heat, which should not be the case as the engine will act as an open-cycle cooler. (ignore the screwiness with the negative heat production on the engine - I was messing with the config files to see if I could fix it for now). To reproduce this, simply construct any craft with a reactor and a thermal engine (turbojet, ramjet or launch nozzle), and start up the engine. Propellant choice doesn't matter. I've tried it with most combinations and no matter what I do, they all overheat super quickly. Here is another image using a timberwind. Same basic problem: (This one went a little weird as mechjeb decided to cut throttle to avoid max-Q being too high, hence the waste heat shot up and down while I took the screenshot. Either way, at full throttle, the timberwind still overheated in a matter of seconds) By contrast, a thermal receiver can eat a whole GW from a nearby microwaver broadcaster, and show only the most minuscule increase in waste-heat: I would hazard a guess that the bug was introduced in commit ba617fd70f96dba67c2d8eac39d5238f5c998634 when the waste heat processing for thermal receivers was improved, but I have no idea where. I'm currently running 1.16.0 on KSP 1.3.1, but this bug appeared before the update to 1.3.1. As far as my save-game is concerned, this is a bit of a game-breaker. I hope that it's possible to patch this, as otherwise most of my vessels are stranded with no propulsion.

Firstly, let me say that I think that this is a fantastic mod, and I'm really looking forward to the new reactor designs. I'm sure that you are very busy implementing your own ideas, and I understand that a person doesn't get into modding in order to make other people's ideas work. With that in mind, how easy/sensible would it be to implement the following things? Magnetic Nozzle Engine This would be a type of engine which can connect onto the dusty plasma reactor or fusion reactors. The idea is that it would simply divert the charged particles resource out the back of the ship for thrust, using the fissionable/fusionable materials as both fuel and re-mass. I've taken a quick look at the numbers. Assuming U235 fission, the maximum theoretical performance is an Isp of 1,192,661, and a thrust of 169.5 N/GW. Pure He3 fusion gives an Isp of 2,073,191 and a thrust of 98.3 N/GW. These are real-world numbers, so I don't know what fudge factors are required (if any) in order to be consistent with the peculiarities of Kerbal physics. Those thrusts look too anaemic to be useful, but I understand that you have had a look at a better physical time-warp system. It may be a useful drive type in the future. Open Cycle Thermal Exhaust Vent I often find that I have a bit of an issue expelling waste heat in the early-tech tree, but that it tends to be very easy later on. Do you think there is any future in a tiny heat vent system which simply uses waste heat to boil a fluid (possibly monoprop) and dumps it, as a way of getting rid of heat? I imagine that it would be a tiny, early-game part suitable for use on probes. If it could be made to only vent when waste heat gets above a certain threshold, it may also see later use as an emergency cooling system on larger vessels. Early Game heat sources/Generators Due to the nature of the parts it creates KSPI tends to centre around the late-game. However, I think that the heat source/generator system is flexible enough that there is a lot of room for early game tech too. For example, a lot of probes require either small amounts of power over a long period (for keeping things running), or large amounts of power over short periods (for transmitting science). I could think of an early game generator (presumably a sterling engine), radioisotope thermal source, and a simple chemical furnace (burning liquid fuel and oxidiser). The generator would be less efficient than the Brayton cycle/KTECs but would be a lot thinner and lighter for small probes and rovers. The furnace would have a surprisingly high thermal power output, and fully throttle itself, but would naturally consume chemical fuel very quickly. This would mean it would only operate for short periods, presumably while transmitting science. It may even see some later use as a backup supply for restarting other power systems. The radioisotope source would be somewhat weedy in output, but it's small size and weight would still make it useful for long duration probes. I could also see some interesting missions being carried out with such tech, for example coupling the radioisotope source with a thermal jet (assuming the source could "store" a decent amount of thermal power), in order to recreate something like the Mars Hopper proposal. Nuclear Salt Water Rocket You obviously know your hypothetical space tech, so you are probably familiar with this concept. Suffice to say that the mod already has Fissionable salts and water as resources. It also has a lack of high thrust engines in the mid game, which this would nicely fill. Assuming that it used fissionable fuel quite inefficiently, this would provide a greater impetus to use the mining mechanics in this mod. This drive also comes high in the "nuclear engines I wouldn't want to be anywhere close to when they are activated" awards, second only to Orion. It seems like an interesting idea, and one that I cannot see anyone else having done so far. These may just be parts for the sake of coming up with more parts, but they may provide inspiration for some interesting mechanics.