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

[GreeningGalaxy]

I think the antimatter reactors as-they-are-now represent antimatter thermal generators; you dump antimatter into a massive excess of normal matter, and all the crazy stuff it produces just gets absorbed and turned into heat (which can be used to run a thermal generator, or to heat propellant). Beam-core propulsion would be a secondary "fuel" mode, where the reactor contains much less regular matter to ensure the charged particles can escape. Alternately, you could instead adjust the magnetic nozzles to work with ThermalPower+propellant so long as the source temperature is high enough to ensure the propellant becomes a plasma. The VASIMR electric propulsion system has a magnetic nozzle that handles plasma up to 1,000,000 K - the plasma is generated in a different way, but that shouldn't really matter as long as it's plasma, yes? That would give you antimatter-thermal (plasma core) rockets with magnetic nozzles. That might work better game-wise than beam-core antimatter rockets; a realistically represented beam-core rocket would have absurdly high ISP (~10,000,000 s) and pathetic thrust at the power levels we have available. The numbers from Project Rho have 10 MN-thrust ... at an utterly insane power level of 500 TW! The 405 GW antimatter rocket would have <10 kN of thrust at that ratio. Increasing ISP decreases how much thrust you get for a given power level.

Right - that's why I like the idea of a 1,250kN 200,000s plasma engine: the power checks out to be easily within the capability of the 405 GW antimatter reactor, and it fulfills the niche of the endgame high-thrust high-Isp antimatter rocket. We really don't need another high-Isp low-thrust propulsion system; those are headaches to use (KSPI magnetic nozzles, plasma engines, and every ion engine mod ever, I'm looking at you) and we already have a whole bunch of them.

You can theoretically just stuff more propellant through a plasma-core rocket to increase your thrust and lower your Isp anyway, so the physics check out. There's no need for a rocket with 800,000s Isp anyway with the Kerbol-sized solar system.

The 10-meganewton figure given on Project Rho for the beam-core engine is the maximum theoretical that you could get from an engine made of matter.

A rocket with an Isp of 10,000,000 seconds (exhaust velocity of 98,000,000 m/s) and a thrust power of 405 gigawatts would have a thrust of just over 4 kilonewtons, but I think you could get away with just injecting more antimatter and getting higher thrusts that way up to a point, but the real issue is not vaporizing your engine when >40% of the input power is turning into heat. The wasteheat generated by my torch drive is almost certainly several orders of magnitude too little, but I pulled some hand-waving that it's not thermalizing the gamma rays and most of the energy is lost that way. I'm not at all sure that's plausible. I wanted ships that use that drive to have to carry the next size bigger radiators than normal, but anyone who's tried to get the maximum possible power out of an antimatter reactor knows that 405 gigawatts is a lot of radiator, and my engine probably should put out close to that in waste heat. Once again, I encourage you to edit that file however you like.

[cicatrix]

I don't normally use those types of receivers... but I know with the thermal receivers if you have more than 2 running at once... it breaks things.

Try starting with only 1 (one) and see if that works.

~Steve

Never mind, figured it out. Just stayed on the launchpad on timewarp for several hours until finally, they started receiving. That is a bit strange since 3 transmitters 120 degrees apart at 800 km should have covered every bit of Kerbin surface with possible exceptions of maybe polar regions (too lazy to to the maths). Apparently I need either to launch more transmitters or re-adjust the orbits of existing ones.

I presume the signal weakens with distance, what's the maximum?

[Yaivenov]

I'd imagine they would, but I don't know for sure. I'm not quite sure how wasteheat production with solar panels works anyway, because it's not in the individual cfgs and I can't find KSPI's module manager patch for it. I'm not sure the NFT solar cells produce any wasteheat by default in any case.

I can confirm that the NFT solar panels do generate waste heat, and it seems commensurate with their energy production. That's why I was unsure about making megajoule generating solar panels as it might bypass the heat generation code (assuming that code is specifically looking at default energy resource generation).

[GreeningGalaxy]

I can confirm that the NFT solar panels do generate waste heat, and it seems commensurate with their energy production. That's why I was unsure about making megajoule generating solar panels as it might bypass the heat generation code (assuming that code is specifically looking at default energy resource generation).

Hmm... guess i can't say I know anything about that, then. You could always just add the megajoules to the solar arrays and leave the electric charge in, which could be construed as cheaty but probably wouldn't be too bad since, unless you're driving NFT plasma engines and KSPI ones at the same time, there aren't a lot of big users of electriccharge that would also be found on a ship using megajoules.

[NeoAcario]

I think I finally know what I want to build next with KSPI... a Station Tug / Station Mover. It was a bit of a pain in my ass to mover this 620ton AM farm into perfect Jool orbit with my 2.5m tug / probe command ship. Maybe I'll build a 3.75m Warp Tug specifically for moving stations around.

~Steve

EDIT:

2.5m Probe Command Tug bringing the Jool AM station in for an 8g aerocapture. Pain in the ass moving 660t with only 2x 1.25m Vacuum Plasma.

Edited November 8, 2014 by NeoAcario

[NeoAcario]

Charged particles from an AM reaction are how the beam-core propulsion mode works. The unstable particles that it produces aren't as convenient to do ChargedParticle things with as the light ions from a fusion reaction (might not be able to run a direct conversion generator), but they should work for ChargedParticle-based propulsion.

Any idea what % would/could be used for charged particle propulsion purposes?

~Steve

[ArcFurnace]

This paper (found in the citations of the Wikipedia article about antimatter rockets) says that just under 40% of the initial rest mass of a proton-antiproton annihilation will be converted into kinetic energy of charged pions (the rest is either the rest mass of the charged and uncharged pions, or kinetic energy of the uncharged pions, which cannot be deflected and used for thrust). The kinetic energy is ~374 MeV/pion, compared to a rest mass of ~209 MeV/pion, so those particles are moving at a substantial fraction of lightspeed. Will edit in velocity calculations once I'm more certain I haven't totally messed them up.

EDIT: The paper itself gives the figure of ISP = 10,000,000 s. The other problem is since a significant fraction of your propellant mass is being converted into energy, you have to use the relativistic rocket equation instead of the standard rocket equation (you wind up getting worse performance, since a substantial fraction of your propellant mass effectively vanishes without doing anything). Also, ~38% of the initial propellant rest mass is converted into energy of the neutral pions, which rapidly decay into high-energy gamma rays. This means that nearly as much energy is converted into deadly radiation spraying in all directions as is coming out of the exhaust jet as useful thrust. Not only will you need shielding to prevent this from killing your crew, you will need heat radiators to keep it from simply vaporizing the shielding. On top of that, the gamma rays are energetic enough to forcibly induce nuclear fission/transmutation, so the shield's going to wind up radioactive even after you turn the engine off.

EDIT #2:

Holy ....... so potentially up to 60% of an AM reactor's energy could be converted into charged particals explicitly for the use of a particle engine?

You get 40% as useful kinetic energy. 22% turns into the rest mass of the charged pions, and the remaining 38% into the rest mass/kinetic energy of uncharged pions (which rapidly decay into gamma rays and start trying to kill things, including but not limited to the crew, the structure of the spacecraft, and the engine itself).

Edited November 8, 2014 by ArcFurnace

[NeoAcario]

Holy ....... so potentially up to 60% of an AM reactor's energy could be converted into charged particals explicitly for the use of a particle engine? That could be nuts! I'd be curious to see what Fractal thinks of the idea. Perhaps a second kind of AM reactor designed with this in mind? I would love to build a wider variety of ships in my purely AM driven space program!

~Steve

EDIT:

Hell, just let us tac on a magnetic nozzle onto an AM reactor and use it that way. Sounds EXACTLY like what it was made for.

[Aghanim]

Is there any config/patch to make KSPi uses Real Fuels? I remember there is one back ago, but I don't know where, and google search doesn't help

[NeoAcario]

Just one quick question:

Why does the 2.5m Cryostat cost over 5 million?

~Steve

[undercoveryankee]

Just one quick question:

Why does the 2.5m Cryostat cost over 5 million?

~Steve

In real life, tritium is extremely expensive. The closest to an "industrial" use it has in the present day, nuclear weapons, doesn't generate enough demand to support large-scale production, and it can't be stockpiled because it decays to helium-3.

The cost in the config file is the cost of the part with all resources full. The cost of the ship is reduced by any resources that aren't actually full in the VAB. Since most of the 5 million is tritium, the default setting with only 2 units of tritium in the tank isn't that expensive.

[Atrius129]

Is there any config/patch to make KSPi uses Real Fuels? I remember there is one back ago, but I don't know where, and google search doesn't help

If I remember correctly, doesnt the CRP in undercoveryankee's sig address this?

Edited November 8, 2014 by Atrius129

[NeoAcario]

The cost in the config file is the cost of the part with all resources full. The cost of the ship is reduced by any resources that aren't actually full in the VAB. Since most of the 5 million is tritium, the default setting with only 2 units of tritium in the tank isn't that expensive.

Afraid you're incorrect. 18,000 Tritium sells for over 40 million. Naturally, there must either be another reason... or there was a mistake somewhere in the pricing. So... which is it? What do we all think the empty 2.5m Cryostat which can hold 18,000 Deuterium and Tritium should cost?

My massive fusion station costs almost 8 million... the vast majority is just the cryostat. This obviously isn't right.

~Steve

[GreeningGalaxy]

You get 40% as useful kinetic energy. 22% turns into the rest mass of the charged pions, and the remaining 38% into the rest mass/kinetic energy of uncharged pions (which rapidly decay into gamma rays and start trying to kill things, including but not limited to the crew, the structure of the spacecraft, and the engine itself).

Sounds like we need Dang It! integration here.

Hmm, looks like if we take 40% of 405 gigawatts (162 gigawatts) and divide that out by 1.1 meganewtons (the thrust of the DT Vista), we get an exhaust velocity of 147,273 m/s or an Isp of 15027, which is slightly worse than the Vista. Guess we'll need to try something else for antimatter torch drives!

(Related fun fact: this means that the the power output of the DT Vista's induced fusion reactions is about 165 gigawatts (15500 s * 9.8 m/s^2 * 1,100,000 N = 167 GW, minus the 2.5 gigawatts of electricity used to power the lasers = 164.5 GW))

One obvious thing to do here would be to use something closer to Project Rho's suggestion and make our 162 GW engine have an Isp of 200,000 seconds and a thrust of 82 kN, but at that point you might as well just strap a generator and a quantum vacuum plasma thruster to the antimatter reactor and enjoy effectively infinite Isp with even better thrust. I suppose we could switch a zero around and get an engine with 20,000 s Isp and 820 kN, which would be more respectable but still a little low-powered. That's why I'm in favor of a multiple-terawatt direct-injection system that doesn't muck around with something as weak as a 405 GW antimatter reactor.

yes, I'm more or less aware of what I just said. o.o

I guess the best thing for this to be is just the next step up from the DT Vista once you have antimatter power- if we go for twice the power (330 GW), we could have an engine with a thrust of 1,500 kN and an Isp of 22,500 s, which is as high as you'd ever need for a Hohmann-abiding planet hopper, but hardly a torchship to Jool. Add a zero and put it at 3.3 TW, and you could do 3,400 kN at 100,000 s (I messed up my math AGAIN, darnit, my engine config currently uses 20 TW, not 2).

Now that I consider that, I think I'm gonna go take a zero off the Isp of my engine (bringing it down to 56,000 s @ 3750 kN) because 20 terawatts seems pretty unlikely.

Anyway, I'm still not sure what exactly everyone else wants to see, but I think I'm getting closer to an antimatter engine I can love.

Afraid you're incorrect. 18,000 Tritium sells for over 40 million. Naturally, there must either be another reason... or there was a mistake somewhere in the pricing. So... which is it? What do we all think the empty 2.5m Cryostat which can hold 18,000 Deuterium and Tritium should cost?

My massive fusion station costs almost 8 million... the vast majority is just the cryostat. This obviously isn't right.

~Steve

5 million does seem a little pricey for a cryostat. By, like, maybe two orders of magnitude.

Although, to be fair, these cryostats seem to be somehow capable of keeping the hydrogen around with zero boiloff as long as they're powered, so maybe they contain some very expensive magic inside them to keep the hydrogen atoms from doing what they normally do and squeezing out between the atoms of the tank. (At least, H2 does that... does deuterium/tritium?)

Edited November 8, 2014 by GreeningGalaxy

[undercoveryankee]

Here's my config to give the AM reactor a charged-particle mode. I have the reactor filling its on-board ChargedParticle storage, but for some reason the magnetic nozzle still insists that its max thrust is zero. Anyone have any idea what I'm missing?

// Proton/antiproton annihilation produces enough of its output in the form of
//  charged pions that it should be possible to use antimatter for things that
//  require ChargedParticles.
// This config is estimated based on some numbers reported on the forums.

REACTOR_FUEL_MODE {
    name = AMChargedParticle
    ReactorType = 32
    GUIName = Antimatter (Charged particle)
    ChargedParticleRatio = 0.4
    MeVPerChargedProduct = 0.7144
    Aneutronic = True
    NormalisedReactionRate = 1.0
    NormalisedPowerConsumption = 1.0
    FUEL {
        name = Antimatter
        FuelName = Antimatter
        UsagePerMW =1.1111111111e-14
        Unit = mg
    }
}

@PART[AntimatterReactor*] {
    RESOURCE {
        name = ChargedParticles
        amount = 0
        maxAmount = #$../RESOURCE[ThermalPower]/maxAmount$
    }
}

[NeoAcario]

5 million does seem a little pricey for a cryostat. By, like, maybe two orders of magnitude.

Although, to be fair, these cryostats seem to be somehow capable of keeping the hydrogen around with zero boiloff as long as they're powered, so maybe they contain some very expensive magic inside them to keep the hydrogen atoms from doing what they normally do and squeezing out between the atoms of the tank. (At least, H2 does that... does deuterium/tritium?)

I'm with you on the fact that they should be expensive... but 5 million mega-bucks (5 billion) seems a bit much. Heck, my 9x 3.75 fusion reactors with a solid state and direct conversion generator each... plus 18 of the large graphine fin radiators is only half as expensive as the cryostat that holds the fuel! Seems a tad off to me. I can't imagine that even a perfectly efficient cryostat would cost 25x as much as a single LARGE FUSION reactor. So.. what should they cost? 50k?

~Steve

[ebigunso]

I just upgraded to KSP 0.25 and I suddenly found all my radiators retracted and without an option to deploy them. What is going on?

My solar panels were fine, so it must be the interstellar that is doing the weird thing. The problem was there regardless of radiator size, I confirmed with small and medium sizes on my craft.

Anyone have an idea?

[NeoAcario]

I just upgraded to KSP 0.25 and I suddenly found all my radiators retracted and without an option to deploy them. What is going on?

My solar panels were fine, so it must be the interstellar that is doing the weird thing. The problem was there regardless of radiator size, I confirmed with small and medium sizes on my craft.

Anyone have an idea?

Might have something to do with the tech tree? Are you using the right one? Don't use the bundled tree loader. It's not supported any more / for 0.25. Use TechManager:

http://forum.kerbalspaceprogram.com/threads/98293-0-25-TechManager-Version-1-1

It's not perfect, yet, but it works

~Steve

[Poodmund]

I was trying to muck around with the HA-1 Aluminium Hybrid Rocket but the node placements in the VAB were acting strangely when trying to use it in an inline configuration. Is this node placement intended as it would leave a large "ghost" gap when connected to something above?

[ebigunso]

I had treeloader deleted, and techmanager not installed due to more serious issues with it (mod preventing save to load in the first place).

That may have been the issue, idk, but I can't try out with TechManager installed due to the problem I stated. Posted bug report already in TechManager thread.

[ABZB]

Here's my config to give the AM reactor a charged-particle mode. I have the reactor filling its on-board ChargedParticle storage, but for some reason the magnetic nozzle still insists that its max thrust is zero. Anyone have any idea what I'm missing?

// Proton/antiproton annihilation produces enough of its output in the form of
//  charged pions that it should be possible to use antimatter for things that
//  require ChargedParticles.
// This config is estimated based on some numbers reported on the forums.

REACTOR_FUEL_MODE {
    name = AMChargedParticle
    ReactorType = 32
    GUIName = Antimatter (Charged particle)
    ChargedParticleRatio = 0.4
    MeVPerChargedProduct = 0.7144
    Aneutronic = True
    NormalisedReactionRate = 1.0
    NormalisedPowerConsumption = 1.0
    FUEL {
        name = Antimatter
        FuelName = Antimatter
        UsagePerMW =1.1111111111e-14
        Unit = mg
    }
}

@PART[AntimatterReactor*] {
    RESOURCE {
        name = ChargedParticles
        amount = 0
        maxAmount = #$../RESOURCE[ThermalPower]/maxAmount$
    }
}

From my playing around with adding reactor types - I think only the fusion reactor module is capable of producing chargedparticles, or the antimatter reactor module is incapable of supporting switching modes. To get around this, The following would work:

@PART[AntimatterReactor*]
{
        RESOURCE
	{
        name = ChargedParticles
        amount = 0
        maxAmount = #$../RESOURCE[ThermalPower]/maxAmount$
         }
	@MODULE[FNAntimatterReactor]
	{
		@name = InterstellarTokamakFusionReator
		powerRequirements = 0
		minimumThrottle = 0
		chargedParticleRatio = 0.4
	}
}

[ABZB]

I noticed that Plutonium-238 is included in the resources. It is used for power generation on probes:

http://en.wikipedia.org/wiki/Plutonium-238

http://www.wired.com/2013/09/plutonium-238-problem/all/

http://www.space.com/20774-plutonium-spacecraft-fuel-nasa-budget.html

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

They are generally 'one piece' systems - by which I mean that they would seem to be translated into KSP as a single part (ie not use the generator parts like the other generators)

I made a small .cfg to implement this for Squad's RTG part:

@PART[rtg]
{
	RESOURCE
	{
		name = Plutonium-238
		amount = .25
		maxAmount = .25
	}
	RESOURCE
	{
		name = ElectricCharge
		amount = 0
		maxAmount = 1000
	}

	!MODULE[ModuleGenerator]{}

	MODULE
	{
		name = ModuleElementRadioactiveDecay
		decayConstant = 2.23944825e-10
		resourceName = Plutonium-238
		decayProduct = ElectricCharge
		convFactor = 10
	}
	MODULE
	{
		name = ModuleElementRadioactiveDecay
		decayConstant = 2.23944825e-10
		resourceName = Plutonium-238
		decayProduct = WasteHeat
		convFactor = .1
	}
}

@RESOURCE_DEFINITION[Plutonium-238]
{
	unitCost = 2304.0
}

I extrapolated the constant for decay Pu-238 from the RL half-lives of Tritium and Pu-238, and the decayconstant for Tritium. The value used here is halved, as I have it decaying into two different things at the same rate (to get wasteheat). I need to verify as to how the decyaconstant works - if that functions properly.

Pu-238 has a similar production/stockpile issue as to Tritium (see links above) so I gave it the cost of Tritium. The amount of Pu-238 given should last for around 50 in-game years (timewarped on launchpad). (seems to go decently with the Voyager probes - they are powered by Pu-238, and are expected to have power until around 2025. The electricity production may be way too high - may need to be fine-tuned.

[NeoAcario]

I noticed that Plutonium-238 is included in the resources. It is used for power generation on probes:

http://en.wikipedia.org/wiki/Plutonium-238

http://www.wired.com/2013/09/plutonium-238-problem/all/

http://www.space.com/20774-plutonium-spacecraft-fuel-nasa-budget.html

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

They are generally 'one piece' systems - by which I mean that they would seem to be translated into KSP as a single part (ie not use the generator parts like the other generators)

I made a small .cfg to implement this for Squad's RTG part:

I extrapolated the constant for decay Pu-238 from the RL half-lives of Tritium and Pu-238, and the decayconstant for Tritium. The value used here is halved, as I have it decaying into two different things at the same rate (to get wasteheat). I need to verify as to how the decyaconstant works - if that functions properly.

Pu-238 has a similar production/stockpile issue as to Tritium (see links above) so I gave it the cost of Tritium. The amount of Pu-238 given should last for around 50 in-game years (timewarped on launchpad). (seems to go decently with the Voyager probes - they are powered by Pu-238, and are expected to have power until around 2025. The electricity production may be way too high - may need to be fine-tuned.

A properly decaying RTG... interchangeable with KAS... with proper weight and cost associated with PU 238... Yeah, I could get behind this.

~Steve

[ABZB]

It seems the decay module scales based on mass - it produces infinite ElectricCharge and wasteheat per unit Pu-238... Also, the convFactor is never actually called in the module, it has no effect. I therefor have made the Pu-238 decay to an intermediate dummy resource, that is then mandatorily converted into EC. I removed wasteheat - all that happens if it overloads is that the radiators explode - it does nothing to the RTG

Now every second about 10 units of RTGHeat should be produced, which is instantly transformed into 4 units of EC. I chose this amount, as it should be enough to sustain many/most RTG antennas+probe power drain, with a small amount left over. It will not be enough to also power the stock ion engine - that would require stacking a few of these, or having a stockpile of EC.

@PART[rtg]
{
	RESOURCE
	{
		name = Plutonium-238
		amount = .25
		maxAmount = .25
	}
	RESOURCE
	{
		name = ElectricCharge
		amount = 0
		maxAmount = 1000
	}
	RESOURCE
	{
		name = RTGHeat
		amount = 0
		maxAmount = 10
	}

	@MODULE[ModuleGenerator]
	{
		%requiresAllInputs = TRUE
		INPUT_RESOURCE
		{
			name = RTGHeat
			rate = 10
		}
		@OUTPUT_RESOURCE[ElectricCharge]
		{
		   @rate = 4
		}
	}

	MODULE
	{
		name = ModuleElementRadioactiveDecay
		decayConstant = 4.4788965e-10
		resourceName = Plutonium-238
		decayProduct = RTGHeat
		convFactor = 1
	}
}

@RESOURCE_DEFINITION[Plutonium-238]
{
	unitCost = 2304.0
}

RESOURCE_DEFINITION
{
  name = RTGHeat
  density = .0001
  flowMode = ALL_VESSEL
  transfer = NONE
  isTweakable = false
}

EDIT: typoed the EC. missed the "@". fixed.

Edited November 9, 2014 by ABZB

[NeoAcario]

It seems the decay module scales based on mass - it produces infinite ElectricCharge and wasteheat per unit Pu-238... Also, the convFactor is never actually called in the module, it has no effect. I therefor have made the Pu-238 decay to an intermediate dummy resource, that is then mandatorily converted into EC. I removed wasteheat - all that happens if it overloads is that the radiators explode - it does nothing to the RTG

Now every second about 10 units of RTGHeat should be produced, which is instantly transformed into 4 units of EC. I chose this amount, as it should be enough to sustain many/most RTG antennas+probe power drain, with a small amount left over. It will not be enough to also power the stock ion engine - that would require stacking a few of these, or having a stockpile of EC.

You don't really need to worry about waste heat with an RTG... by design it handles it's own heat management. So no big deal there. So 4 EC/sec. That's a heck of a lot more than the 45/min that the standard RTG produces. Two questions: Does the EC/sec decrease as the resource does? How does this compare to a 0.1m radius by 0.75m tall core PU238 RTG in reality?

You're piqued my interest

~Steve