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[1.12.x] Kerbal Atomics: fancy nuclear engines! (January 22, 2022)


Nertea

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@Nertea, I was reading about Nuclear Propulsion on the web, because.. well, who doesn't? And I ran across this:

https://en.m.wikipedia.org/wiki/Project_Timberwind

You might already be familiar with it, but I saw the efficiencies, masses, thrust, etc, and noted that they are far better performing than what's available in KSP or Kerbal Atomics. So much so, that I dare say if these were the specs of KA engines, it'd be game breaking.

Am I missing something, or is KSP in general that far behind what real, 25 year old projects could have given us? Perhaps to balance out that in KSP we wouldn't care about spewing radiation all over, so balance has to be made? Perhaps to account for radiation shielding so crew could survive? Could future NFE mods which include radiation effects possibly provide these sorts of performance, at the cost of killing anyone within kilometers of the reactors?

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14 hours ago, AmpCat said:

@Nertea, I was reading about Nuclear Propulsion on the web, because.. well, who doesn't? And I ran across this:

https://en.m.wikipedia.org/wiki/Project_Timberwind

You might already be familiar with it, but I saw the efficiencies, masses, thrust, etc, and noted that they are far better performing than what's available in KSP or Kerbal Atomics. So much so, that I dare say if these were the specs of KA engines, it'd be game breaking.

Am I missing something, or is KSP in general that far behind what real, 25 year old projects could have given us? Perhaps to balance out that in KSP we wouldn't care about spewing radiation all over, so balance has to be made? Perhaps to account for radiation shielding so crew could survive? Could future NFE mods which include radiation effects possibly provide these sorts of performance, at the cost of killing anyone within kilometers of the reactors?

The answer is KSP. If you make 100% realistic parts (this applies to standard combustion engines too), you get much, much higher TWRs and better mass ratios than KSP has. Check out, for example, a list of the real TWRs of various rocket engines and compare them to their approximate KSP equivalents. This applies to the LV-N too, which has a TWR of like... 2, whereas the NERVA if I recall correctly sits around 4-5. Since this mod extends stock, I'm not about to go and make a bunch of engines that are that far out of the performance envelope for nuclear engines. The KA engines are indeed better than the stock envelope, with the Neptune being based off the SNTP NTRs, with a TWR of ~3 and a more or less correct Isp. They're quite a bit better...

You don't notice this fully because you're used to the LV-N using magical unicorn dust plus LF in order to produce 800s of Isp on some kind of dense kerosene-like fuel :P. 

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11 hours ago, Nertea said:

The answer is KSP. If you make 100% realistic parts (this applies to standard combustion engines too), you get much, much higher TWRs and better mass ratios than KSP has. Check out, for example, a list of the real TWRs of various rocket engines and compare them to their approximate KSP equivalents. This applies to the LV-N too, which has a TWR of like... 2, whereas the NERVA if I recall correctly sits around 4-5. Since this mod extends stock, I'm not about to go and make a bunch of engines that are that far out of the performance envelope for nuclear engines. The KA engines are indeed better than the stock envelope, with the Neptune being based off the SNTP NTRs, with a TWR of ~3 and a more or less correct Isp. They're quite a bit better...

You don't notice this fully because you're used to the LV-N using magical unicorn dust plus LF in order to produce 800s of Isp on some kind of dense kerosene-like fuel :P. 

Yeah, all makes sense. Though this gives me an idea of making a Flinstones/PeterPan mod, where everything runs off crude oil and pixie dust.

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@Nertea, I've a question about the emancipator engine :

The small engine seems to be there to provide active cooling without using the main engine. The problem is this second engine depends on throttle too. So you can't  reduce thrust on the main engine because that reduces thrust on the small cooling engine too and the nuke rapidly goes off with the security.

This cooling engine, should always burn at max thrust if activated whatever throttle is applied (much like a booster, but you could shut it down)

Or maybe I didn't understand something.

Edited by Warzouz
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I've issuer with timewarp and nuke temperatures. When I timewarp, the temp increase a lot.

For example on the Liberator design, I used cooling to allow it to work at 1% at 6000K. But as I timewarp, the ship start to heat up (turning red). If I don't time warp, temp stays stable.

On the emancipator, I use the small engine to keep it at 18000K until my node approaches (which is very hard to handle as the small engine wreck the burn time calculation). But the ship heats up a lot and explodes.

Have you any hint ?

Thx

EDIT : OK, for the emancipator, it blows up after I deactivate the engine

Edited by Warzouz
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I saw this over on the Atomic Age thread. Was there Atomic Age support included in the KerbalAtomicsNFE Extras patch once upon a time? Unless I am missing something, the most current patch only includes KA and stock support. I have sort of hodge podged my own Atomic Age (as well as VSR) patch using NFE reactors, but I mostly made it up as I went along trying to keep at as balanced as I could, while not having a thorough understanding of all the modules NFE adds in for Fission Reactors.

I ask in part, because support does exist for both Atomic Age and VSR via the NTR patch.

Spoiler

 

Cheers,

Edited by Stratickus
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On 4/5/2017 at 4:12 PM, Stratickus said:

I saw this over on the Atomic Age thread. Was there Atomic Age support included in the KerbalAtomicsNFE Extras patch once upon a time? Unless I am missing something, the most current patch only includes KA and stock support. I have sort of hodge podged my own Atomic Age (as well as VSR) patch using NFE reactors, but I mostly made it up as I went along trying to keep at as balanced as I could, while not having a thorough understanding of all the modules NFE adds in for Fission Reactors.

No, no support... patch is still too experimental.

On 4/4/2017 at 2:34 PM, Warzouz said:

@Nertea, I've a question about the emancipator engine :

The small engine seems to be there to provide active cooling without using the main engine. The problem is this second engine depends on throttle too. So you can't  reduce thrust on the main engine because that reduces thrust on the small cooling engine too and the nuke rapidly goes off with the security.

This cooling engine, should always burn at max thrust if activated whatever throttle is applied (much like a booster, but you could shut it down)

Or maybe I didn't understand something.

It's not a cooling engine, it's the roll control turbopump exhaust. It shouldn't even cool much, guess that's something to look at.

On 4/5/2017 at 9:46 AM, Warzouz said:

 

I've issuer with timewarp and nuke temperatures. When I timewarp, the temp increase a lot.

For example on the Liberator design, I used cooling to allow it to work at 1% at 6000K. But as I timewarp, the ship start to heat up (turning red). If I don't time warp, temp stays stable.

On the emancipator, I use the small engine to keep it at 18000K until my node approaches (which is very hard to handle as the small engine wreck the burn time calculation). But the ship heats up a lot and explodes.

Have you any hint ?

 

Read the conversation between me and Ampcat a bit up. You can use the patch file i provided in one post to reduce this.

 

 

 

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Btw Nertea, I found that nuclear reactors don't seem to start until I activate them via staging (similar how KSP had earlier an issue with engine gimbal). It's a bit impractical, particuarly when you use a trimodal engine in your top stage and want to use the reactor during the entire mission.

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Sigh, just don't use the patch anymore guys. There's obviously a lot of issues and I'll take it out of the extras next version. Until an indefinite time.

Edited by Nertea
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5 minutes ago, Nertea said:

Sigh, just don't use the patch anymore guys. There's obviously a lot of issues and I'll take it out of the extras next version. Until an indefinite time.

Aw, that patch is friggin awesome tho :( (actually didn't encounter any major issues till yet, either)

Well, its your call.

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Oh sure, the basic mod is pretty reliable. I did not know there were so many questions about the patch, always just thought that part was kinda work in progress anyway.

I can see why it would make sense to leave it out for a modder.

Edited by Temeter
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Eh... I'm just frustrated with it. It would be nice if interested parties, like you, @AmpCat, @Tau137 few others who I know have used it extensively, would come together here over the next couple weeks and hash out what needs to be done to fix the existing problems. The current piecemeal thing is that I fix one thing, don't hear anything for months, then wake up to a bunch of other new bugs and things. The user base is very small so it's been in a state of "well it kinda works" for so long that it's very annoying. I really want to be able to promote it to stable

Here's what I *know* needs to be fixed:

  • Reactor startup can't be forced on an engine (stages the engine) so a solution needs to be found
  • An exclusion needs to exist to stop engine roll control turbopumps from cooling the entire reactor
  • Exhaust conflicts with radiator cooling and won't allow other radiators to cool engine part's Internal heat store (Core is fine)
  • Solid core reactors should get more realistic core temperatures

Can we try to figure out where all the problems are?

 

 

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1 hour ago, Nertea said:

There's obviously a lot of issues and I'll take it out of the extras next version. Until an indefinite time.

That's a shame. I for one like it, but I understand the headache it must cause. I have run into problems myself, but did not realize it was an experimental patch, otherwise I would have approached it differently.

1 hour ago, Nertea said:

This mod would be fairly stable without it, that's for sure. 95% of the questions I field are tracked directly to that bit.

I thought I saw talk of an NFT (KA) wiki. I imagine that would clear up a lot of questions if you could just point people to that once the patch becomes stable.

35 minutes ago, Nertea said:

Eh... I'm just frustrated with it. It would be nice if interested parties, like you, @AmpCat, @Tau137 few others who I know have used it extensively, would come together here over the next couple weeks and hash out what needs to be done to fix the existing problems. The current piecemeal thing is that I fix one thing, don't hear anything for months, then wake up to a bunch of other new bugs and things. The user base is very small so it's been in a state of "well it kinda works" for so long that it's very annoying. I really want to be able to promote it to stable.

I would count myself as an interested party, however, I cannot say that I have used it extensively, nor that I would be able to offer much assistance. All that same, a concerted effort is probably the way to go. I'm sure many would like to be able to help and in a way give back. 

Cheers,

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28 minutes ago, Stratickus said:

I would count myself as an interested party, however, I cannot say that I have used it extensively, nor that I would be able to offer much assistance. All that same, a concerted effort is probably the way to go. I'm sure many would like to be able to help and in a way give back. 

 

Well if you've used it, you might have opinions, so you can speak up if you like :).

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1 hour ago, Nertea said:

Can we try to figure out where all the problems are?

I'd love to, and have done quite a bit of cfg work for a bunch mods, but I lack any knowledge of the more complex coding or commands/relationships. Probably not much I can help with, sorry :(

(that's why I don't ask you to fix it, would be quite selfish with a free mod ^^)

Edited by Temeter
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@Nertea The only reason I mention anything is because I like the modded mod. That's why I spent so much time trying to characterize it. I'd not bother with it at all if it wasn't interesting and fun.

I agree with the list you posted, and so far, haven't found any other issues with it. I think part of the problem is that it doesn't seem the base KSP thermal system is flexible enough to handle the complexity you're trying to include.

I'm loathed to suggest more work, but it may be there's another technical approach that would give the same or similar effect to the user, but mesh with the limitations inherent in KSP better? Making a plan for doing a little more work to make these 'done', and move on, might be less work in the end. For example:

  1.  While the roll control pumps are real cool, how much value do they add to the experience? Maybe keep them and just write off the heat removed as a 'feature'? Would it be simpler to remove them?
  2. The patch you posted for the part thermal issues controls the problem well enough that, while not technically 'fixed', is good enough to be 'patched' in my mind, unless there's some other drawback to it. In fact, upping it a little more would make it behave that much better.
  3. Reactor startup is annoying, but I just set the engine's throttle to 0% and stage it. Yeah, makes it hard on a trimodal to use the reactor independently. I just mount a second, independent reactor. I don't know enough about how KSP parts work, but maybe there's an approach that makes the reactor portion behave more like a separate part. Maybe it just should be a second part. Same could be said for the other engines. I think it would be real clunky to make engines two-part features (nozzle and reactor), but other popular mods have done far worse. This may also solve other thermal issues.
  4. Realistic temperatures? I think we've already discussed how not much in KSP is realistic anyway. As long as it's balanced with the rest of the game well, good enough.

Don't despair. Near Future Tech is one of the best mods for KSP. Has some of the best modeled parts in KSP.

But I agree, don't kill your time trying to perfect this if KSP isn't going to cooperate. Re-scope it into something that can be made to work.

Maybe make the reactors randomly explode to remind people it's experimental. :P

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5 hours ago, AmpCat said:
  1. Reactor startup is annoying, but I just set the engine's throttle to 0% and stage it. Yeah, makes it hard on a trimodal to use the reactor independently. I just mount a second, independent reactor. I don't know enough about how KSP parts work, but maybe there's an approach that makes the reactor portion behave more like a separate part. Maybe it just should be a second part. Same could be said for the other engines. I think it would be real clunky to make engines two-part features (nozzle and reactor), but other popular mods have done far worse. This may also solve other thermal issues.

I tried that approach in my last game, and the independant reactor idea doesn't seem to work too well, since you can't control the final heat like you can with reactors. It's always going toward max heat, and at least the small trimodal has only 12 days of nuclear fuel (which probably makes sense for a nuclear engine). Output is also quite marginal until higher heat levels are reached.

You could use it for short, reliable bursts of electricity, but the benefit is quite limited. Not sure if it is worth to make changes as big on that basis, and it would hurt the non-NTR functionality.

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15 hours ago, Nertea said:

Eh... I'm just frustrated with it. It would be nice if interested parties, like you, @AmpCat, @Tau137 few others who I know have used it extensively, would come together here over the next couple weeks and hash out what needs to be done to fix the existing problems. The current piecemeal thing is that I fix one thing, don't hear anything for months, then wake up to a bunch of other new bugs and things. The user base is very small so it's been in a state of "well it kinda works" for so long that it's very annoying. I really want to be able to promote it to stable

Here's what I *know* needs to be fixed:

  • Reactor startup can't be forced on an engine (stages the engine) so a solution needs to be found
  • An exclusion needs to exist to stop engine roll control turbopumps from cooling the entire reactor
  • Exhaust conflicts with radiator cooling and won't allow other radiators to cool engine part's Internal heat store (Core is fine)
  • Solid core reactors should get more realistic core temperatures

Can we try to figure out where all the problems are?

As I couldn't use the NFE Patch, I tried to remove it. But, it feels LOT was lost in the process. So I managed to tweak the NFE patch

  • I kept the Uranium consumption
  • I kept the capacity to reload uranium

That's a little bit better than the Atomic mod alone.

Spoiler

// MM Config to set fancy nuclear engines if NFE is around
@PART[ntr-gc-25-2]:NEEDS[NearFutureElectrical]
{
    @RESOURCE[EnrichedUranium]
    {
        @amount = 160
        @maxAmount = 160
    }
    RESOURCE
    {
        name = DepletedFuel
        amount = 0
        maxAmount = 160
    }

    MODULE
    {
        name = RadioactiveStorageContainer
        DangerousFuel = DepletedFuel
        SafeFuel = EnrichedUranium
        // What enginer level is needed to transfer the safe fuel
        EngineerLevelForSafe = 1
        // What enginer level is needed to transfer the dangerous fuel
        EngineerLevelForDangerous = 3
        // Max temp for transferring fuel into or out of the part
        MaxTempForTransfer = 400
        // kW of heat per unit of waste
        HeatFluxPerWasteUnit = 5
    }
}
@PART[ntr-gc-25-1]:NEEDS[NearFutureElectrical]
{
    RESOURCE
    {
        name = EnrichedUranium
        amount = 160
        maxAmount = 160
    }
    RESOURCE
    {
        name = DepletedFuel
        amount = 0
        maxAmount = 160
    }

    MODULE
    {
        name = RadioactiveStorageContainer
        DangerousFuel = DepletedFuel
        SafeFuel = EnrichedUranium
        // What enginer level is needed to transfer the safe fuel
        EngineerLevelForSafe = 1
        // What enginer level is needed to transfer the dangerous fuel
        EngineerLevelForDangerous = 3
        // Max temp for transferring fuel into or out of the part
        MaxTempForTransfer = 400
        // kW of heat per unit of waste
        HeatFluxPerWasteUnit = 5
    }
}
@PART[ntr-sc-25-1]:NEEDS[NearFutureElectrical]
{
    description = A large nuclear reactor is coupled to an equally large expansion nozzle to heat propellant to comfortably high temperatures. Using a secondary cooling loop, a portion of the reactor's heat runs a small generator that produces around 100 kW of electricity, even when the engine is idle. The Poseidon can also augment its thrust by injecting oxygen into the propellant, creating a tremendous stream of flame and a corresponding boost in thrust. Post-Terran accepts literally no liability for anything related to this part of operation at all.
    RESOURCE
    {
        name = EnrichedUranium
        amount = 140
        maxAmount = 140
    }
    RESOURCE
    {
        name = DepletedFuel
        amount = 0
        maxAmount = 140
    }
    MODULE
    {
        name = RadioactiveStorageContainer
        DangerousFuel = DepletedFuel
        SafeFuel = EnrichedUranium
        // What enginer level is needed to transfer the safe fuel
        EngineerLevelForSafe = 1
        // What enginer level is needed to transfer the dangerous fuel
        EngineerLevelForDangerous = 3
        // Max temp for transferring fuel into or out of the part
        MaxTempForTransfer = 400
        // kW of heat per unit of waste
        HeatFluxPerWasteUnit = 5
    }
}
@PART[ntr-sc-125-1]:NEEDS[NearFutureElectrical]
{
    description = Improving upon the basic LV-N formula, the Neptune uses excess heat generated by the reactor to run a compact generator system, producing 20 kW of electric power while the engine is running or idle. The engine also features a third mode (hence the name) where oxidizer is injected into the exhaust, causing instantaneous combustion and reportedly violent acceleration.
    RESOURCE
    {
        name = EnrichedUranium
        amount = 55
        maxAmount = 55
    }
    RESOURCE
    {
        name = DepletedFuel
        amount = 0
        maxAmount = 55
    }
    MODULE
    {
        name = RadioactiveStorageContainer
        DangerousFuel = DepletedFuel
        SafeFuel = EnrichedUranium
        // What enginer level is needed to transfer the safe fuel
        EngineerLevelForSafe = 1
        // What enginer level is needed to transfer the dangerous fuel
        EngineerLevelForDangerous = 3
        // Max temp for transferring fuel into or out of the part
        MaxTempForTransfer = 400
        // kW of heat per unit of waste
        HeatFluxPerWasteUnit = 5
    }
}
@PART[ntr-sc-125-2]:NEEDS[NearFutureElectrical]
{
    RESOURCE
    {
        name = EnrichedUranium
        amount = 45
        maxAmount = 45
    }
    RESOURCE
    {
        name = DepletedFuel
        amount = 0
        maxAmount = 45
    }
    MODULE
    {
        name = RadioactiveStorageContainer
        DangerousFuel = DepletedFuel
        SafeFuel = EnrichedUranium
        // What enginer level is needed to transfer the safe fuel
        EngineerLevelForSafe = 1
        // What enginer level is needed to transfer the dangerous fuel
        EngineerLevelForDangerous = 3
        // Max temp for transferring fuel into or out of the part
        MaxTempForTransfer = 400
        // kW of heat per unit of waste
        HeatFluxPerWasteUnit = 5
    }
}
@PART[nuclearEngine]:NEEDS[NearFutureElectrical]:AFTER[KerbalAtomics]
{
    RESOURCE
    {
        name = EnrichedUranium
        amount = 50
        maxAmount = 50
    }
    RESOURCE
    {
        name = DepletedFuel
        amount = 0
        maxAmount = 50
    }
    MODULE
    {
        name = RadioactiveStorageContainer
        DangerousFuel = DepletedFuel
        SafeFuel = EnrichedUranium
        // What enginer level is needed to transfer the safe fuel
        EngineerLevelForSafe = 1
        // What enginer level is needed to transfer the dangerous fuel
        EngineerLevelForDangerous = 3
        // Max temp for transferring fuel into or out of the part
        MaxTempForTransfer = 400
        // kW of heat per unit of waste
        HeatFluxPerWasteUnit = 5
    }
}

 

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Issues aren't usually hard to fix. It's fixing issues and then new, independent issues appearing that's extremely frustrating. If we could figure out what is non-optimal right now for me to fix then we at least have a roadmap that I can work towards. 

9 hours ago, Temeter said:

I tried that approach in my last game, and the independant reactor idea doesn't seem to work too well, since you can't control the final heat like you can with reactors. It's always going toward max heat, and at least the small trimodal has only 12 days of nuclear fuel (which probably makes sense for a nuclear engine). Output is also quite marginal until higher heat levels are reached.

You can control the final heat in any reactor with the slider. 

14 hours ago, AmpCat said:
  1. Realistic temperatures? I think we've already discussed how not much in KSP is realistic anyway. As long as it's balanced with the rest of the game well, good enough.

In this case it's just a number used for scaling. Cosmetic.

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I've identified about how much more time I want to spend on this mod, and targeted a number of possible parts for that time. So... vote in the poll to decide the last two KA parts. 

http://www.strawpoll.me/12769123

Don't suggest nuclear ramjets or anything like that. Here's some further information on each choice.

  • 2.5m or 3.75m thrust-optimized closed-cycle GCNR - aerospike or low-expansion nozzle, some loss of Isp, a good boost in TWR. Something that might run the GCNR Liberty Ship.
  • 2.5m liquid-core NTR - somewhere between the Poseidon and the Liberator in performance, extendable nozzle
  • 2.5m thrust-optimized solid-core NTR - aerospike or low-expansion nozzle, perhaps based on the nuclear DC-X SSTO.
  • 0.625m mini solid-core NTR - based off the small MITEE engine, small footprint, extendable nozzle

If you posted other, write a comment here. 

Edited by Nertea
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2 hours ago, Nertea said:
  • 2.5m or 3.75m thrust-optimized closed-cycle GCNR - aerospike or low-expansion nozzle, some loss of Isp, a good boost in TWR. Something that might run the GCNR Liberty Ship.
  • 2.5m liquid-core NTR - somewhere between the Poseidon and the Liberator in performance, extendable nozzle
  • 2.5m thrust-optimized solid-core NTR - aerospike or low-expansion nozzle, perhaps based on the nuclear DC-X SSTO.
  • 0.625m mini solid-core NTR - based off the small MITEE engine, small footprint, extendable nozzle

I voted for the big (preferably 3.75m) thrust-optimized GCNR and the mini 0.625m engine, partly because they'd be differentiated on size from the current offerings. 

Also, the idea of a nuclear-driven launch vehicle is intriguing and to my knowledge has not been represented in KSP mods to date. I was unable to open the DC-X SSTO PDF, so I went with my gut instinct of "bigger must be better."

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