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[0.25]KSP Interstellar (Magnetic Nozzles, ISRU Revamp) Version 0.13


Fractal_UK
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I'm not able to produce tritium. My setup: 2.5m unupgraded fission reactor, 1.5m generator, science lab, UF4 cans, lithium cans, DT cans. The cans are attached radially but have fuel lines running to and from them (I don't know if that's necessary, is it? Will the cans supply fuel radially? I haven't quite figured them out yet). When I was on the ground, it would produce 0.45 kg/day tritium only if set time warp to maximum. If I do the same thing in orbit, nothing happens. Nothing happens when I switch away from the ship, either.

Any advice? Thanks!

Edit: Realized I was using the wrong search method on these forums so I looked around, and I understand now that you need high time warp rates to see anything produced. However, once my rig is in space it's not producing anything even at high warp.

Edited by StallSpin
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The problem with this calculations is that you do not consider vessel dry mass/fuel mass ratio.

I tried to use 3.75 reactor and ended up with totally impractical amounts of fuel needed to be carried with it to have dV comparable to simple LV-n based designs. And without mainsail unlocked... i just gave up. Too many launches, orbital assembly, huge and heavy ship... and result will be similar to ~20-30T single launch LV-n based ship.

2.5 reactor is much more practical, but still seems to be needed only if you decided "i will not use LV-n's", otherwise LV-n based designs are much more flexible and easy.

That doesn't matter in the context of my calculations. I was comparing one reactor + thermal nozzle to an equal weight of LV-Ns, which would have the same mass ratio. You are correct in stating that smaller craft will be better off using LV-Ns. The point at which Reactors + Thermal Nozzles become useful is the point at which you need to attatch 20+ LV-Ns to your rocket to get an acceptable level of thrust, assuming you're using the 3.75m reactor.

I played around with my Transfer Stage Design calculator and got these numbers:

       Payload Mass   # Engines  Engine Mass  TWR    Fuel Mass   Total Mass      dV
LV-Ns 50 t 20 45 t 0.46 178.07 t 263.07 t 8000 m/s
Reactor 50 t 1 46 t 0.32 181.76 t 267.76 t 10000 m/s

The conclusion I draw from that is this:

If you want to send a single interplanetary probe, use LV-Ns. They're lightweight and flexible.

If you want to launch a manned mothership that can fly to each of Jool's moons, send a lander, and then return to Kerbin all in one go, use a reactor. It's much more powerful.

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Yes they are two different things. But the Scoops DO work. The Jet flies. Remember, I'm not saying that the engine doesn't WORK, it does. I'm saying that the Intercooler doesn't work. Unless the Intercooler only works with Intakes, which is possible... But I would like some kind of definitive answer if possible.

The scoop does not provide IntakeAir, IntakeAtm or anything similar. It compresses material from the atmosphere into fuel tanks, it is thus a totally seperate mechanic from the precoolers.

The only constraint on precooler operation is that they have to be attached directly to the intake. You can put reactors and thermal jets, rapier engines, etc anywhere you want on the aircraft.

Edit: You can, in theory, use scoops to run engines but the ways to do this are 1) Go to Jool, where you can harvest LiquidFuel from the atmosphere and use a high Isp engine to harvest more fuel than you use up or 2) Carry asymmetric quantities of LiquidFuel and Oxidiser and replenish the Oxidiser from the atmosphere as you fly.

Edited by Fractal_UK
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The scoop does not provide IntakeAir, IntakeAtm or anything similar. It compresses material from the atmosphere into fuel tanks, it is thus a totally seperate mechanic from the precoolers.

The only constraint on precooler operation is that they have to be attached directly to the intake. You can put reactors and thermal jets, rapier engines, etc anywhere you want on the aircraft.

Edit: You can, in theory, use scoops to run engines but the ways to do this are 1) Go to Jool, where you can harvest LiquidFuel from the atmosphere and use a high Isp engine to harvest more fuel than you use up or 2) Carry asymmetric quantities of LiquidFuel and Oxidiser and replenish the Oxidiser from the atmosphere as you fly.

After double-checking it turns out I was mistaken, I'm using an Intake, not a Scoop. So, to re-iterate, the setup is Intake-Precooler-Nuclear Reactor-Thermal Turbojet. Precoolers show "Precooler status: Offline".

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The conclusion I draw from that is this:

If you want to send a single interplanetary probe, use LV-Ns. They're lightweight and flexible.

If you want to launch a manned mothership that can fly to each of Jool's moons, send a lander, and then return to Kerbin all in one go, use a reactor. It's much more powerful.

Yes, i agree.

But 260T... i generally avoid vessels that large.

Also do this calculations include staging, which is possible (and should be used) for LV-Ns?

I do not say that this reactors are useless, and i built such ships based on 2.5m reactor, but sometimes they are just too inefficient...

p.s. also in this calculations LV-N based ship has higher TWR, if you reduce amount of engines to match TWR results will be a bit different too.

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Particle Bed/Dusty Plasma Fission

To further develop some interesting nuclear technologies, I bring you some more fission reactor designs. They are quite different to the existing Molten Salt/Gas Core designs and should offer some interesting options.

qjLC67i.png

(Model by AArtisan)

Particle Bed Reactor

The particle bed reactor is a fission reactor that uses small particles of nuclear fuel encased in pyrolitic carbon and zirconium carbide, the particulate design means these particles have huge surface area and are incredibly efficient at heat transfer. The cernamic materials used mean they can also withstand far higher temperatures. Additionally, a particle bed reactor is designed to be resistant to overheating, it takes advantage of a negative feedback caused by doppler broadening to progressively reduce the reactor power output as the temperature increases. This creates a nice passive safety feature, should the temperature ever get too high, the reactor simply stops producing power.

This reactor runs at an optimal temperature of 1173K but can operate all the way to up 2700K. The amount of power the reactor produces depends on the temperature, at 1173K, it can generate its rated maximum. At higher temperature, you will produce less power.

This creates an interesting situation in space travel because the specific impulse depends upon temperature, thus you can try to add lots of radiators to maintain the highest power rating, giving you the most thrust or you can allow the reactor to heat up a little and lose a bit of thrust but achieve a higher specific impulse. At optimal temperature, Isp is significantly lower than the existing un-upgraded fission reactors but, if you allow the reactors to heat up a bit more, values of just over 1000s are possible. That's pretty interesting for an early tech!

Unfortunately, it suffers from significantly lesser fuel burn-up than the existing MSRs and the complicated fuel pellet design means that reprocessing cannot be done on the fly. Instead, you will have to make do with simple refueling - fortunately, this isn't too hard. This reactor uses UraniumNitride fuel, it comes fully stocked in the VAB and this fuel can be produced from Uranium Tetraflouride and Ammonia at your nearest refinery. (Tip: This makes Laythe an excellent location to deploy this design in a self-sustaining way).

With proper tweaking, you might find this design can offer some unique and interesting capabilities, especially for thermal rocket applications.

Dusty Plasma Reactor

This is a very interesting design of reactor which suspends a "dusty plasma" of microscopic solid particles electrostatically. The advantage of this design is a feature rarely seen in fission reactors - the ability to use direct conversion on charged particles. Like certain fusion reactions, a significant proportion of the energy of all fission reactions is initially released in the form of fast moving charged "fission fragments," these are simply the lighter atomic nuclei that result from the fissioning of a heavy atom. In most fission reactor designs, the fission fragments are prevented from escaping so virtually all of the power is generated as heat. This design is one that specifically allows the fission fragments to escape, that means you can hook it up to a Direct Conversion generator and enjoy the huge efficiency gain that design brings.

The downside of the dusty plasma is that it runs at very low temperature (4100K) for an upgraded reactor because the particles in the dusty plasma must remain solid. That means specific impulse with a thermal rocket is a fairly uninteresting (for the tech level) 1432.5s. These reactors also don't get a huge power upgrade over the original pebble bed design but the upgrade does offer increased fuel burn-up meaning that despite the (moderately) increased power, the upgrade actually uses less fuel!

Of course, they are the earliest opportunity in the tech tree to make substantial use of Direct Conversion power and should be rather nice if you're looking for electrical power rather than good thermal rocket performance.

Important Note

I have changed the densities of UF4, ThF4, Actinides and DepletedFuel into units of t/l instead of t/m^3, this makes them more consistent with most of the other densities found in Interstellar and the general drive amongst parts of the modding community to adopt those units. It also gives you a more conveniently sized unit for the resource bars in game and basically looks a lot nicer. Your existing nuclear reactors will be automatically swapped to these units without interruption, so you don't need to worry about it breaking your existing reactors, however the hex cans of nuclear fuel probably cannot be upgraded in the same way, that means you may have to send out some new fuel cannisters for your ships after the update.

Edited by Fractal_UK
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Yes, the engines do start overheating above Mach 2.5. So they are not working. Try it yourself. I'd be interested in the result.

AkucKnZ.png

I dumped 340T+ of fuel and after taking off noticed the sun was setting so, I let Mechjeb take it for a flight around the block.

P.S.

Looking good Fractal_UK, I cant wait :)

Edited by Donziboy2
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Yes, i agree.

But 260T... i generally avoid vessels that large.

Also do this calculations include staging, which is possible (and should be used) for LV-Ns?

I do not say that this reactors are useless, and i built such ships based on 2.5m reactor, but sometimes they are just too inefficient...

p.s. also in this calculations LV-N based ship has higher TWR, if you reduce amount of engines to match TWR results will be a bit different too.

If by staging you mean drop tanks, you can set up drop tanks the same way for both engines. If you mean dropping engines, then you can save some mass with the LV-Ns. I made the assumption that this craft would be used as a reusable interplanetary tug, which sounds reasonable for something that has 10 km/s dV with a 50 t payload.

The numbers I posted were set to maintain close to the same engine mass and total ship mass. Here are more cases. They all assume a payload of 50 tons, as the reactor is only useful for very[/] heavy spacecraft.

I've highlighted the numbers where one design was significantly better than the other. The conclusion remains the same.


[B]Optimized to match engine mass and total craft mass.[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 50 t 20 45 t [u]0.45[/u] 172.81 t 267.81 t 8140 m/s
Reactor 50 t 1 46 t 0.32 171.76 t 267.76 t [u]10000 m/s[/u]


[B]Optimized to match engine mass and TWR[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 50 t 20 45 t 0.32 280.79 t 375.79 t [u]10800 m/s[/u]
Reactor 50 t 1 46 t 0.32 [u]171.76 t[/u] [u]267.76 t[/u] 10000 m/s


[B]Optimized to match engine mass and dV[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 50 t 20 45 t [u]0.36[/u] 244.38 t 339.38 t 10000 m/s
Reactor 50 t 1 46 t 0.32 [u]171.76 t[/u] [u]267.76 t[/u] 10000 m/s


[B]Optimized to match TWR and total craft mass[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 50 t 14 [u]31.5 t[/u] 0.32 184.82 t 266.32 t 9300 m/s
Reactor 50 t 1 46 t 0.32 [u]171.76 t[/u] 267.76 t [u]10000 m/s[/u]


[B]Optimized to match TWR and dV[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 50 t 17 [u]38.25 t[/u] 0.32 227.02 t 315.27 t 10000 m/s
Reactor 50 t 1 46 t 0.32 [u]171.76 t[/u] [u]267.76 t[/u] 10000 m/s


[B]Optimized to match dV and total craft mass[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 50 t 11 [u]24.75 t[/u] 0.25 192.29 t 267.04 t 10000 m/s
Reactor 50 t 1 46 t [u]0.32[/u] [u]171.76 t[/u] 267.76 t 10000 m/s

Note: Assumes 3.75m unupgraded fission reactor with Thorium fuel

For the sake of completeness, here's the same calculations with a 10 t payload (suitable for a heavy probe) and 6 km/s dV (suitable for a round trip to most planets), which show the situations in which the LV-N shines.


[B]Optimized to match engine mass and total craft mass.[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 10 t 20 45 t [u]1.03[/u] 63.06 t 118.06 t 6000 m/s
Reactor 10 t 1 46 t 0.73 62.40 t 118.40 t [u]7400 m/s[/u]


[B]Optimized to match engine mass and TWR[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 10 t 20 45 t 0.73 117.17 t 174.42 t [u]8750 m/s[/u]
Reactor 10 t 1 46 t 0.73 [u]62.40 t[/u] [u]118.40 t[/u] 7400 m/s


[B]Optimized to match engine mass and dV[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 10 t 20 45 t [u]0.86[/u] 86.10 t 141.10 t 7400 m/s
Reactor 10 t 1 46 t 0.73 [u]62.40 t[/u] [u]118.40 t[/u] 7400 m/s


[B]Optimized to match TWR and total craft mass[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 10 t 14 [u]31.5 t[/u] 0.73 75.64 t 117.14 t [u]8150 m/s[/u]
Reactor 10 t 1 46 t 0.73 [u]62.40 t[/u] 118.40 t 7400 m/s


[B]Optimized to match TWR and dV[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 10 t 10 [u]22.5 t[/u] 0.73 [u]50.88 t[/u] [u]83.38 t[/u] 7400 m/s
Reactor 10 t 1 46 t 0.73 62.40 t 118.40 t 7400 m/s


[B]Optimized to match dV and total craft mass[/B]

Payload Mass # Engines Engine Mass TWR Fuel Mass Total Mass dV
LV-Ns 10 t 16 [u]36 t[/u] [u]0.82[/u] 72.01 t 118.01 t 7400 m/s
Reactor 10 t 1 46 t 0.73 [u]62.40 t[/u] 118.40 t 7400 m/s

Note: Assumes 3.75m unupgraded fission reactor with Thorium fuel

The last three entries in each table are of the most interest.

You would choose TWR if it matters to you how long your burns will take.

You would choose Total Craft Mass if it matters to you how much weight you have to lift into space.

You would choose dV if it matters to you how long you can go without refueling.

You can pick two to equalize, and let the third float.

For TWR + Mass: The Reactor has more dV when it comes to the heavy payload. The LV-N has more dV when it comes to the light payload.

For TWR + dV: The Reactor leads to a lighter total craft for the heavy payload. The LV-N leads to a lighter total craft with the light payload.

For dV + Mass: The Reactor has a higher TWR with the heavy payload. The LV-N has a higher TWR when carrying the light payload.

It seems that without a doubt, the LV-N is superior for light spacecraft in almost every way, and the Reactor is superior for heavy spacecraft in almost every way.

...whew. I really need to program this sort of analysis ability into my calculator.

Edited by RadHazard
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Will we get some new containers for nuclear fuel instead standard hexcans?

I mean both looks and functioality, something wider, maybe of the size of therman nozzle woudl be better than long thin hexcan.

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@Donziboy: If you could do me a quick favor. Check that same design (or a smaller one) with two of the engines without precoolers and report back what you find. I would highly recommend having the engines set up to hotkeys on toggle so you don't immediately blow them up. That's where I believe the bug lies. The ghost heat from the engines without precoolers is spilling over to the engines with them; even after closing intakes and shutting the engines completely off. The engines with precoolers still heat to explosion temperatures.

@Fractal Looks fairly solid. I sense another career restart in my future with all these new toys >.>

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I'm sure somebody's brought this up, so I'm sorry. I'm having a problem where there are certain parts missing, even in sandbox.

These seem to include the aluminum hybrid engine, the microwave transmitters, and most of the odd containers for things like say, argon and stuff. If you have a fix, I'd appreciate it.

Many parts in the mod are located by reference so you must install in the correct location as stated in the install instructions. If you don't, many parts will not appear and many others will break.

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Is it possible to have a ground based generator on kerbin transmit power to a relay in low kerbin orbit?

And why not?

You will probably need few relays in KSO, one above the point where reactors are located.

One of crazy experiments of how to make it fast and easy (sorry for dark image, but it was night and i was too lazy to warp some time and launch it again):

8yOzkHT.jpg

1700T "rover", no steering, but it is not needed, it went ~5km away from KSC before running out of fuel. 46GW using unupgraded (molten salt) reactors.

BTW relays seem to work a bit strange. I planned to use big transceiver located on ship as relay for lander but it did not work. Lander (with smallest receivers) still had few hundreds of MW of power (above dres), while ship with transceiver could receive ~33GW if switched to receiver mode. Is this intended?

Edited by Lightwarrior
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So, I'm trying to start up a series of ISRU refineries. However, I've not been able to get them to do anything at all. I understand that some of the processes take a long time, but even on 100000x I wasn't seeing change. Maybe I'm not over a deposit of anything or whatever.

Anyway, one of the items on the list mentioned water. So I thought I would put one in the water near KSC. Nothing changed.

How do you turn on the various "mining" aspects? How do you get it to refine anything?

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Thanks for the reply I kind of have my head wrapped around the sizing of the radiators now although the numbers when I look at my ships still have be a tad baffled. I have gleaned that the max heat for an item appears to be 1 ec/s = 1kW and the rate that an item generated heat is 1/2 kw / 1 ec. I have a pair of the regualr radial radiators on a sat with four gigantor solar arrays. These generate peak 18 ec / s so I can expect a max heat rating of 18 kW and a rate of 9 kw. Each of the four arrays stabilize at 165 / 1800. The two radiators are at 655 / 3500 K radiating 10 kW. the info on the solar arrays is 17.43 ec/s, heat production 8.71 kW (which matches the expected 1/2 kW / ec) and the waste heat is stable at 165/1800. The total waste heat for the sat is 993 / 807200. It is these total numbers that I don't understand. They do not seem to be a multiple of any of the values for either the radiators or the arrays?

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And why not?

You will probably need few relays in KSO, one above the point where reactors are located.

One of crazy experiments of how to make it fast and easy (sorry for dark image, but it was night and i was too lazy to warp some time and launch it again):

1700T "rover", no steering, but it is not needed, it went ~5km away from KSC before running out of fuel. 46GW using unupgraded (molten salt) reactors.

BTW relays seem to work a bit strange. I planned to use big transceiver located on ship as relay for lander but it did not work. Lander (with smallest receivers) still had few hundreds of MW of power (above dres), while ship with transceiver could receive ~33GW if switched to receiver mode. Is this intended?

I think it's intended, look at how much bigger the surface area for the transceiver is. My rover has 25 reactors/generators and beams almost 110GW. They're upgraded, it's 1200 tons. Had to use 5 Vista engines to get it up the hill behind KSC.

Edited by AndreyATGB
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LV-N is obviously work by different rules then KSPI NTR. By KSPI rules it must have same stats as kiwi(from tech level and reactor size), deplete nuclear fuel and need of thermal management, but by squad rules it much more powerfull and work at the same way as chemical rockets. It's like to have small squad antenna together with Remote tech - it's small not need line of sight and work at any distance - if you need to bring big dish and to have relay network by RT rules - obviosly it will looks more lightweight and flexible. Or one Pod wich not use life support system, and kerbals will live in it forever when with other pods they need lot of heavy supplys. It's just not consistently to have both. I'm not suggest to change something but I think it's incorrect to compare them. To make "better stats then anything" engine is easy anyway.

Fractal already tried to change stock rules with solar panels and jets(by the way, I'm ok with need of precoolers for hypersonic, well, close to , kerbin scale make everything wierd, but over half(or even almost) of orbital speed is somehow portray what mean to be hypersonic for earth, I belive.

What I'm about, oh yes - looks like it cool toþ much - it pervent engine thermal emission animation to show up - maybe somehow to change some curve, to make it cool at full only when engine is overheating, or somethng like this, maybe it's not physically correct, I don't know, but will help with FX)

I don't know why he leave lv-n as is, maybe because it will cause some discontent(?) (when people become angry), as it was with other changes of rules.

Edited by zzz
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I think it's intended, look at how much bigger the surface area for the transceiver is.

...

My rover has 25 reactors/generators and beams almost 110GW. They're upgraded, it's 1200 tons. Had to use 5 Vista engines to get it up the hill behind KSC.

Yes, but the idea was that larger transceiver will work as relay, and smaller one will receive power from it and not directly from relays which orbit kerbin.

...

I still have no vista so i had to use wheels, it is just unreal to fly this thing when the most powerfull engine you have is skipper.

Actually i multiplied science cost of each node in tree.cfg by factor of 4, it makes career much more interesting because i now have to do few missions after each new node, instead of getting few nodes in single mission. I had to use power thansmission because reactor upgrade now have cost of 12000 science and to get this i will need to set few labs and visit some planets, which is a bit hard with just thermal nozzles/unupgraded reactors.

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Particle Bed/Dusty Plasma Fission

Dusty Plasma Reactor

This is a very interesting design of reactor which suspends a "dusty plasma" of microscopic solid particles electrostatically. The advantage of this design is a feature rarely seen in fission reactors - the ability to use direct conversion on charged particles. Like certain fusion reactions, a significant proportion of the energy of all fission reactions is initially released in the form of fast moving charged "fission fragments," these are simply the lighter atomic nuclei that result from the fissioning of a heavy atom. In most fission reactor designs, the fission fragments are prevented from escaping so virtually all of the power is generated as heat. This design is one that specifically allows the fission fragments to escape, that means you can hook it up to a Direct Conversion generator and enjoy the huge efficiency gain that design brings.

The downside of the dusty plasma is that it runs at very low temperature (4100K) for an upgraded reactor because the particles in the dusty plasma must remain solid. That means specific impulse with a thermal rocket is a fairly uninteresting (for the tech level) 1432.5s. These reactors also don't get a huge power upgrade over the original pebble bed design but the upgrade does offer increased fuel burn-up meaning that despite the (moderately) increased power, the upgrade actually uses less fuel!

Of course, they are the earliest opportunity in the tech tree to make substantial use of Direct Conversion power and should be rather nice if you're looking for electrical power rather than good thermal rocket performance.

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.

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LV-N is obviously work by different rules then KSPI NTR. By KSPI rules it must have same stats as kiwi(from tech level and reactor size), deplete nuclear fuel and need of thermal management, but by squad rules it much more powerfull and work at the same way as chemical rockets. It's like to have small squad antenna together with Remote tech - it's small not need line of sight and work at any distance - if you need to bring big dish and to have relay network by RT rules - obviosly it will looks more lightweight and flexible. Or one Pod wich not use life support system, and kerbals will live in it forever when with other pods they need lot of heavy supplys. It's just not consistently to have both. I'm not suggest to change something but I think it's incorrect to compare them. To make "better stats then anything" engine is easy anyway.

The main problem with the LV-N is that it is just a chemical rocket with a big nuclear sticker on it. The stats aren't crazily powerful for what it represents, though the TWR is significantly higher than the high power real life Phoebus 1 and 2 designs, the nuclear reactor designs in Interstellar are more sophisticated than these early NTRs too. The main problem that I can see with the LV-N, however, is the fact that it just works forever while your have LiquidFuel/Oxidiser. All the real NERVA rockets were totally sealed units meaning that you had a fixed amount of nuclear fuel inside and when it ran out, you'd have a huge piece of junk attached to your spaceship no matter how much fuel you had. There would be sufficient nuclear fuel in the unit for only minutes of engine burning.

I could change it to make it burn up a fixed supply of nuclear fuel and switch it from using LFO to LiquidFuel, the main impact of this change would be that it would be make very large ships using a small number of LV-Ns at low TWR very hard to build, smaller ships wouldn't really be affected by this part but it would make LV-Ns non-reuseable. At first glance, it sounds like a relatively balanced change, but I'm interested if it is something more people would be happy to see.

Fractal already tried to change stock rules with solar panels and jets(by the way, I'm ok with need of precoolers for hypersonic, well, close to , kerbin scale make everything wierd, but over half(or even almost) of orbital speed is somehow portray what mean to be hypersonic for earth, I belive.

What I'm about, oh yes - looks like it cool toþ much - it pervent engine thermal emission animation to show up - maybe somehow to change some curve, to make it cool at full only when engine is overheating, or somethng like this, maybe it's not physically correct, I don't know, but will help with FX)

I don't know why he leave lv-n as is, maybe because it will cause some discontent(?) (when people become angry), as it was with other changes of rules.

The main thing with the precoolers is to try and make the challenge of building spaceplanes in KSP a bit more like doing it in real life, when 0.23 arrived, and you could now easily build aircraft that simply fly up to essentially orbital velocity in the atmosphere and use the tiniest drop of fuel to circularise (you could kind of do this before but it required a lot more work), it seemed that wasn't really being represented well. In real life, you could reach around 20% of orbital velocity with a standard airbreathing jet, this is about right for the SABRE engine as proposed too. The early flight is the most expensive part because you have thick atmosphere and little velocity to reduce gravity drag, so you'd expect to save a bit more than 20% of total delta-v to orbit.

For the purposes of KSP, I decided to keep the precooler velocity requirements about the same as in real life, meaning because of Kerbin's small size you can achieve over 60% of orbital velocity without even using a precooler - you can easily build KSP SSTO aircraft without even using them so I can't say I've managed to make anything massively more realistic but at least it adds an extra design constraint and a bit more depth to spaceplane flight.

Of course, the nice thing about using real numbers is you could try it with RSS without modification and then you'd have a very interesting engineering challenge.

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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.

This is a planned feature for the future, in fact the dusty plasma reactor and the creation of the distinction between thermal power and charged particles was actually done partially to facilitate this kind of addition so I've been doing background work in this direction.

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.

Maybe, I'd have to look into whether there are any designs that would actually be able to do this effectively. You have open cycle cooling through thermal rockets already, which can be handy. I'll think more about this one.

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.

I actually created an Interstellar RTG part module which consumes a Plutonium-238 resource to produce ElectricCharge and ThermalPower. You could attach it to thermal rockets too and use it in similar ways to the ones described in that article as well as attach generators to it to produce power more efficiently. The main problem with the idea is that Pu-238 isn't really versatile enough to fit all these requirements, if you want thrust, you need to use a shorter half-life, higher activity material. That article was where I got the idea, actually.

It's relatively easy to use the existing code I have to produce chemical power generation equipment, different types of RTGs, etc.

Oddly, in KSP, RTGs are one of the latest techs in the game and I'm not really sure why or what the justification for that is since they were regularly used in the 60s and 70s. In any case, it's still something to think about.

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.

NSWR is something I've thought about adding for a while, I never did it back in the early days of Interstellar because it needed to be a part upgrade (back before career mode was added) but there was no suitable base part. I just haven't revisted the idea since then, there isn't really an obstacle to adding it now.

There would have to be some representation of the radiation consequences and it's one of those drives I can't see even Kerbals would want being used while within the atmosphere of their planet. In some ways it's probably worse than the DT Vista, I mean, the DT Vista will kill anyone nearby and slowly make the launchpad radioactive but the NSWR will spread long lived uranium, other actinides and high activity fission projects all across the planet's atmosphere for Kerbal children to inhale (maybe this is why everyone wears space suits on Kerbin?). Once in space, it's not really an issue anymore because the exhaust moves fast enough to escape the solar system so unless you're pointing it directly at something, it's fine.

Though something like that could act as a balancing factor as well. My overriding experience of this drive is playing the original High Frontier boardgame, people would race to the moon to build it, then zoom around the solar system and win the game easily because it was substantially more powerful than any other combination of parts.

Edited by Fractal_UK
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And why not?

You will probably need few relays in KSO, one above the point where reactors are located.

One of crazy experiments of how to make it fast and easy (sorry for dark image, but it was night and i was too lazy to warp some time and launch it again):

1700T "rover", no steering, but it is not needed, it went ~5km away from KSC before running out of fuel. 46GW using unupgraded (molten salt) reactors.

I actualy like that design you came up with. I prety much copied it except I stuck a plasma on the back. a 2.5 plasma runing off argon can get cruising speeds up in the mid 30s to low 40s m/s and still hold a reasonable 20ish uphill behind ksp. that and 6 tanks can push it prety much to the mountains if you wanted. of note if you go plasma and send a second one out(or more) dont turn on the receiver to siphon off more power for more thrust. I reached rather unsafe velocities very quickly and had to send out another one when the front end nosedived on a pothole and the whole thing accordioned.

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I really could use some help with the waste heat thing as it's now starting to **** me off! I had a sat network of 6 commsats plus a space station that I had to retrofit or relaunch to add radiators. The station seems to be okay but the waste heat keeps rising on the commsats and I should have ample radiator capacity.

The only things that should be generating waste heat are four gigantor solar panels according to what I understand each panel will generate 18ec * 1/2 kW / 1ec or 9kW and they have a max waste heat value of 18 ec * 1kW / ec or 18 kW. I put 2x the regular radial radiator which according to the note in the VAB says will dissipate ~50 kW each. That should be 100 kW of heat dissipation for two of them.

So why is my wast heat for my solar panels continuing to rise???

I just spent 4 hours relaunching 6 commsats and retrofitting my space station and I am going to be really pissed if I have to do it all over again. I really must know EXACTLY how to size these radiators because guessing and then having to relaunch every thing is NOT AN OPTION!

Here are the screen shots of the Commsat. You can see it has 4 solar panels and 2 radial radiators. The limit for each solar panel is 1800 and the value just keeps rising!!! Will it stabilize at some point or do I not have enough radiators?

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