KSP Interstellar Extended Continued Development Thread

[kendoka15]

I don't know if this is a known bug but after reverting to VAB I sometimes find that the 2.5m Electric Generator for my fusion powered launch vehicle has reverted to the "Direct Conversion Generator" type without my input

(I usually find out in-flight )

[FreeThinker]

I don't know if this is a known bug but after reverting to VAB I sometimes find that the 2.5m Electric Generator for my fusion powered launch vehicle has reverted to the "Direct Conversion Generator" type without my input

(I usually find out in-flight )

I believe this is a known bug/ feature depending where you stand. Personally I find it annoying.

[FreeThinker]

I wonder if you could use LqdHelium as an thermal/electro propellant, it might be usefull then you go to the moon looking for Helium3 you will procuess also excess amount of waste Helium4

Electrothermal

The electrothermal category groups the devices where electromagnetic fields are used to generate a plasma to increase the temperature of the bulk propellant. The thermal energy imparted to the propellant gas is then converted into kinetic energy by a nozzle of either solid material or magnetic fields. Low molecular weight gases (e.g. hydrogen, helium, ammonia) are preferred propellants for this kind of system.

An electrothermal engine uses a nozzle to convert the heat of a gas into the linear motion of its molecules so it is a true rocket even though the energy producing the heat comes from an external source.

Performance of electrothermal systems in terms of specific impulse (Isp) is somewhat modest (500 to ~1000 seconds), but exceeds that of cold gas thrusters, monopropellant rockets, and even most bipropellant rockets. In the USSR, electrothermal engines were used since 1971; the Soviet "Meteor-3", "Meteor-Priroda", "Resurs-O" satellite series and the Russian "Elektro" satellite are equipped with them.^[15] Electrothermal systems by Aerojet (MR-510) are currently used on Lockheed Martin A2100 satellites using hydrazine as a propellant.

• Arcjet
  
• Microwave arcjet
  
• Resistojet
  

Intrestingly, it mentions that both helium and ammonia can be effectively used in electric themal engines.

Alternatively, propellant could be used in a RistoJet

In a resistojet, the propellant is heated via a resistance element (ohmic heating) after which it is expanded in a nozzle. Typical propellants used include hydrogen, helium, ammonia, nitrogen, but also water and carbon dioxide.

Another important issue are the materials used. The material properties to a large extent limit the temperatures and therefore the achievable performances. Suitable materials for the electrical resistance of high performance resistojets are rhenium, tungsten, tantalum, molybdenum, platinum or their alloys. As heat exchanger material grain stabilised platinum may be used. This material provides good oxidation resistance at high temperatures and resistance to creep deformation. The grain stabiliser, typically zirconium oxide, works to minimise the grain growth that occurs because of the exposition at high temperatures for long periods of time. For high temperature electric insulators boron nitride has been effective.

Exhaust velocities of up to 10 km/s are feasible using hydrogen propellant, whereas the performance of conventional hydrazine monopropellant thruster can be increased by 25-28% to over 300 s using resistance heating. Thrust efficiencies in excess of 70% and thrust levels up to 0.5 N have been demonstrated. The latter though can be simply increased by increasing the power input.

Restojets, might be intresting as an alternative for Thermal Noozles when used with light Oxidising liquid agents like Water en CO2

Edit, Hydrozine is often mentioned as a thermal electric propellant. I wonder if Hydrozine can also be used in thermal nozzles. Even in a simple thruster it decomposes into

1. 3 N₂H₄ → 4 NH₃ + N₂
   
2. N₂H₄ → N₂ + 2 H₂
   
3. 4 NH₃ + N₂H₄ → 3 N₂ + 8 H₂
   

The heat from the thermal noozle should break down all remaining NH₃ into Nitrogen and Hydrogen

Edited March 20, 2015 by FreeThinker

[FreeThinker]

Question: When using the Community Tech Tree, do we need to select it using TechManager, or do we select the unofficial KSPI tech tree?

Yes you need to use techmanager to activate the Community Tech Tree, but you are adviced only to use one Techtree!

Edited March 21, 2015 by FreeThinker

[ABZB]

From my understanding Plutonium-238 is an artificial resource which cannot be found in the wild, instead it should be able to create it from natural occurring Uranium deposits.

- - - Updated - - -.

That is true - it has a quite short half-life, and has to be intentionally bred in nuclear reactors (much like tritium). It is EXTREMELY useful in RL for any probe/rover that can't afford to rely on solar panels. In RL, this is a gigantic problem, as production ceased completely, as it was only produced as a byproduct of breeding aimed at WMD isotopes.

I made a MM .cfg that converts the stock RTG to use the KSPI radioactive decay module to convert Plutonium-238 into electricity. ATM, it is not balanced (i think) - I think it might last too long for the timescale on which KSP operates. In any case, link:

https://www.dropbox.com/s/g74fcjr7f7ps4dn/better_RTG.cfg?dl=0

[Taki117]

Yes you need to use techmanager to activate the Community Tech Tree, but you are adviced only to use one Techtree!

This explains so much, thank you. I had it installed, but was using the unofficial KSPI tech tree and wondering why parts weren't showing up where they were supposed to, this fixes everything!

[FreeThinker]

This explains so much, thank you. I had it installed, but was using the unofficial KSPI tech tree and wondering why parts weren't showing up where they were supposed to, this fixes everything!

This reminds me to create a full download which exclude the unofficial KSPI techtree

[FreeThinker]

Version 0.7.30 for Kerbal Space Program 0.90

Released on 2015-03-21

• Made Soot Buildup Persistent and affect overall performance
  
• Made Soot Buildup cleaning constant
  
• Soot buildup will effect Engine cooling
  
• Soot buildup will effect engine maximum performance
  
• Soot buildup is now represented as a percentage in the part Gui
  
• Added Fuel Switch to inline Methane Tank and Nitrogen Cryostat
  
• Added Cross Feeder to radial tanks
  

Edited March 21, 2015 by FreeThinker

[Insanitic]

I have a really weird bug I'm encountering.

In the VAB/SPH, when I mouse over a reactor in the part menu, the picture/model of the reactor starts enlarging by itself, until it disappears. I saw my debug log and it says argument out of exception.

Here's a pic of it:

[FreeThinker]

From what I understand is triggered by parts that contain more than one resource. But the underlying cause is something different. This is not a KSPI error, it just manifest in KSPI faster.

Please do some more searching

[MatterBeam]

Hi.

i have three problems after installing the latest versions of Tweakscale and KSPI-E:

Near Future Electric engines still use thousands of electric current instead of MW. This was supposed to be fixed in the latest KSPI-E update?

I cannot find the different sized reactors of KSPI. There is only one size for the different categories, (particle bed reactors 1.25m Sethlans and and that Akula) while I should have unlocked several different sizes by now. I believe this is either a part pruner problem, or the unlocks are only nodes for tweakscale instead of separate parts.

The previous problem is exacerbated by the fact that KSPI-E has somehow broken tweakscale. Maybe it is the fix you asked us to install along with this mod, but I cannot resize ANYTHING.

Can you help?

[Taki117]

I have a really weird bug I'm encountering.

In the VAB/SPH, when I mouse over a reactor in the part menu, the picture/model of the reactor starts enlarging by itself, until it disappears. I saw my debug log and it says argument out of exception.

Here's a pic of it:

This should fix that.

http://forum.kerbalspaceprogram.com/threads/63109-0-23-Modulefixer?p=1259754#post1259754

[FreeThinker]

Near Future Electric engines still use thousands of electric current instead of MW. This was supposed to be fixed in the latest KSPI-E update?

Well if NearFutureElectrical is installed, Near Future Electric engines will continue to use Kilowatts instead of MetaWatt

- - - Updated - - -

I cannot find the different sized reactors of KSPI. There is only one size for the different categories, (particle bed reactors 1.25m Sethlans and and that Akula) while I should have unlocked several different sizes by now. I believe this is either a part pruner problem, or the unlocks are only nodes for tweakscale instead of separate parts.

Well the reactors should now only have 1 or 2 parts, but they should be re scalable. Are you using the latest stable Tweakscale (v1.52.1)

)?

- - - Updated - - -

Maybe it is the fix you asked us to install along with this mod, but I cannot resize ANYTHING.

What Fix? It's quite some time ago I asked people to install a tweakscale fix... Edited March 22, 2015 by FreeThinker

[MatterBeam]

Well if NearFutureElectrical is installed, Near Future Electric engines will continue to use Kilowatts instead of MetaWatt

The thing is, the info tab still lists their consumption in Ec/s. Is there any way to convert that into kW or even MW?

Well the reactors should now only have 1 or 2 parts, but they should be re scalable. Are you using the latest stable Tweakscale (v1.52.1)

)?

Yes, I have the latest version, and I installed the required tweakscale fix on top. Nothing can be scaled, whether they are KSPI parts or regular parts. This is why I was wondering, until a fix for that is found, if it were possible to revert to the older multiple parts in the part catalog display.

[FreeThinker]

Yes, I have the latest version, and I installed the required tweakscale fix on top. Nothing can be scaled, whether they are KSPI parts or regular parts. This is why I was wondering, until a fix for that is found, if it were possible to revert to the older multiple parts in the part catalog display.

There is no fix anymore, just install the latest version of tweakscale. I think your fix is the problem

[Northstar1989]

Hydrozine is often mentioned as a thermal electric propellant. I wonder if Hydrozine can also be used in thermal nozzles.

You *COULD* use Hydrazine (monopropellant) in a thermal rocket- but it's EXTREMELY toxic (much worse than a little radioactivity!), so its use in this capacity would have to be altogether banned within the atmosphere- is there even a way to implement this is KSP?

Also, the list of resource-abundances I posted before seems to be mostly correct- except for the abundances given for Jool/Jupiter...

See the following post for an updated table of elemental abundances for Jupiter:

http://forum.kerbalspaceprogram.com/threads/91998-0-90-Community-Resource-Pack-0-3-3-2015-01-27?p=1799834&viewfull=1#post1799834

I still need to figure out what kind of Ammonia and Methane abundances that corresponds to, but the other resources found on Jool/Jupiter (noble gasses, Nitrogen, etc.) should be relatively intuitive from that...

Most of the resources should be considerably less abundant for Jool than in the first list I posted, but LqdHelium/Helium-4 (and by connection Helium-3, which remains in the same ratio to Helium-4) gets a substantial increase of about 2% total volume abundance (from 13.6 to 15.7%)

Will post an updated/corrected list soon...

Regards,

Northstar

Edited March 22, 2015 by Northstar1989

[MatterBeam]

There is no fix anymore, just install the latest version of tweakscale. I think your fix is the problem

Removed the KSPI folders and fix and Tweakscale, reinstalled KSPI without fix, and latest version of tweakscale, and the latter still does not work.

[FreeThinker]

For our next upcomming feature, watch how we start with 3 Ammonia filled tanks

In space, where the first 2 Ammonia tanks are empty, we switch their contents

Now we convert our remaining Ammonia into Nitrogen and Hydrogen

This should finally makes Ammonia a resource which can replace LiquidFuel and the reconfigurable tanks makes refueling in wild much easier!

- - - Updated - - -

I uploaded Version 0.8.0 for Kerbal Space Program 0.90 Released on at KerbalStuff

Changelog:

• Added InterstellarFuelSwitcher, a modified FSfuelSwitch (by snjo) for Interstellar which allows switching fuel configuration after it is emptied
  

Edited March 22, 2015 by FreeThinker

[Yemo]

While working on mod integration for the SETI-BalanceMod I once again hit the ec definition bump.

Too many mods with different ec assumptions, so I asked in the CommunityResourcePack about it, any input from you guys is very welcome!

[FreeThinker]

You *COULD* use Hydrazine (monopropellant) in a thermal rocket- but it's EXTREMELY toxic (much worse than a little radioactivity!), so its use in this capacity would have to be altogether banned within the atmosphere- is there even a way to implement this is KSP?

Wouldn't the high temperatures in an advanced NTR (3000K+) disintegrate most Hydrazine into harmless basic chemicals like Nitrogen and Hydrogen? Perhaps we can add some Oxygen and convert the remaining hydrogen into Water.

I wonder if there is anyway we can accurately calculate it's expected Isp.

- - - Updated - - -

Removed the KSPI folders and fix and Tweakscale, reinstalled KSPI without fix, and latest version of tweakscale, and the latter still does not work.

Are you sure you followed all my instructions on the OP, I'm sorry but I cannot seem to reproduce your problem. Perhaps some other mod is interfering. Has anyone else have the same problem?

Edited March 24, 2015 by FreeThinker

[Northstar1989]

Wouldn't the high temperatures in a advanced NTR (3000K+) disintegrate most Hydrazine into harmless basic chemicals like Nitrogen and Hydrogen? Perhaps we can add some Oxygen and convert the remaining hydrogen into Water.

I wonder if there is anyway we can accurately calculate it's expected Isp.

Most of the Hydrazine would disintegrate, yes. The key word is "most". Hydrazine is so highly toxic that even the tiny amount that didn't get broken down by the reactor would be enough to make the launch site toxic to breathe near for days afterwards..

Of course, the Russians launch hypergolic rockets powered by only slightly less toxic Hydrazine-derivatives (MMH and/or UDMH plus NTO as an oxidizer) all the time, and they manage not to kill off too many people from the toxicity... So I guess it wouldn't be quite as much of a regulatory nightmare as I made it out to be... Still, you wouldn't catch me within a mile of that launch site without at least a respirator mask handy. Nuclear rockets don't make me nervous (most radiation-exposure from a launch accident would be short-lived before personnel evacuated and highly localized to the area)- Hydrazine rockets on the other hand, now THOSE make me nervous, and much more rightfully so with their cloud of highly toxic GAS that will form after a launch accident...

(The flash point of Hydrazine is only 91 degrees Celsius, and it can explode at any temperature over 4.7 degrees Celsius- so any nuclear rocket accident is easily going to release a giant boiling cloud of Hydrazine-enriched Ammonia, Nitrogen, and Hydrogen- the last of which will combust with atmospheric Oxygen, making the accident even worse... The LC50 is just 747 mg/m³ in rats, meaning if you get exposed to less than a gram of the stuff you have a more than 50% chance of dying- and a Hydrazine Thermal Rocket would have several metric TONS of Hydrazine onboard at a bare minimum...)

The ISP can be calculated from the final mixture of the exhaust-gasses (two-thirds Hydrogen and one-third Nitrogen) with an adjustment to the exhaust velocity from the energy consumed by the reaction to break down the Hydrazine. Essentially forget that you ever had Hydrazine present in the first place and just treat it as a slightly weaker Nitrogen + Hydrogen thermal rocket... (the main advantage of Hydrazine being that it's a much more efficient means of storing the same fuel mass of Nitrogen and Hydrogen in that ratio)

Regards,

Northstar

Edited March 23, 2015 by Northstar1989

[Northstar1989]

OK, sometimes it pays to check your assumptions before you stick your foot in your mouth...

The Gibbs Free Energy of Formation of Hydrazine is positive 149.2 kJ/mol at 289 K (15.85 C) and 1 atm, which means energy is actually released when it breaks down (I should have figured this from the performance of Hydrazine-based RCS thrusters, actually...)

http://www2.ucdsb.on.ca/tiss/stretton/database/inorganic_thermo.htm

The Enthalpy (50.6 kJ/mol) and Entropy (121.2 J/mol*K) are both positive as well, which means that the reaction is spontaneous under all reaction conditions (unlike, say, the formation of Ammonia- which has a negative Enthalpy but a positive Entropy- meaning that its formation will be spontaneous at low temperatures but its decay will be spontaneous at high temperatures, and that the decay of Ammonia is Endothermic and will actually somewhat reduce the exhaust temperature- albeit accompanied by a large increase in the exhaust-pressure that leads to an increase in the total usable exhaust-energy...) and as the increase in Entropy is due to an increase in the number of gas molecules will always increase both the temperature AND pressure of the exhaust stream...

This means that Hydrazine will actually perform BETTER than a corresponding mixture of Hydrogen and Nitrogen- leading to a higher total Thrust for the same fuel-flow (and thus better ISP than a 2:1 mixture of Hydrogen and Nitrogen...)

How much better? Well, Hydrazine has an Enthalpy of formation of 50.6 kJ/mol, and an Entropy of 121.2 J/mol*K, meaning that you will get a Gibbs Free Energy for Hydrazine-decay at 3000 K (in the operating-range of a typical fission Nuclear Thermal Rocket) of:

-50.6 kJ/mol + (-121.2 J/mol*K * 3000 K) = -50.6 kJ/mol - 363600 J/mol = -50.6 kJ/mol - 363.6 kJ/mol = -414.2 kJ/mol

Notice that this is quite a bit more energy than you got at 289 K, due to the positive Entropy of formation of Hydrazine...

Hydrazine has a molar mass of 32.0452 g/mol, meaning you will get (414.2 kJ/mol) / 32.0452 g/mol = 12.9255 kJ/g or MW/kg from Hydrazine-decay at 3000 Kelvin...

This means that an engine passing 1 metric ton of Hydrazine a second will gain almost 13 GW of extra exhaust energy just from the Hydrazine-decay reaction!

More calculations will be needed to determine how much of an increase in Thrust/MW of reactor power and Thrust/kg of fuel this would actually represent for our Nuclear Thermal Rockets, with their current Thrust/MW and ISP's for other fuels...

Regards,

Northstar

Edited March 23, 2015 by Northstar1989

[Northstar1989]

OK, so a starting-point here is to figure out how many kN/s the Hydrazine-decay reaction would add to a 1 metric ton/second Thermal Rocket operating at 3000 K before you even consider the Thrust from the nuclear reactor... (this is a VERY high mass flow rate for a Thermal Rocket, by the way- equating to a volumetric fuel-flow rate through the turbopump of around 1000/1.021 = 979.432 liters/second given Hydrazine's density of 1.021 kg/liter at STP...)

Before we begin, a reminder about units:

1 kiloNewton (kN) = 1000 kg*m/s²

1 kiloJoule (kJ) = 1000 kg*m²s²

1 kiloWatt (kW) = 1000 kg*m²s³

So, a kiloJoule equals a kiloWatt * second, and a kiloWatt equals a kiloNewton * m/s... (1 kJ = 1 kW*s, 1 kW = 1 kN*m/s)

Anyways, you get 12.9255 MW/kg*s from the Hydrazine-decay reaction at 3000 K... This could lead to a variety of Thrust levels depending on the Exhaust Velocity in accordance with the following equation:

Power = 1/2 Thrust * Exhaust Velocity

At an Exhaust Velocity of 9806.65 m/s (1000 seconds ISP) you get 659.02 kN of extra Thrust with a 100% efficient 1000 kg/s Hydrazine Thermal Rocket...

At an Exhaust Velocity of 6864.655 m/s (700 seconds ISP) you get 945.45 kN of extra Thrust with a 100% efficient 1000 kg/s Hydrazine Thermal Rocket...

At an Exhaust Velocity of 4903.325 m/s (500 seconds ISP) you get 1318.03 kN of extra Thrust with a 100% efficient 1000 kg/s Hydrazine Thermal Rocket...

Notice I made a point of saying this is with a 100% efficient Thermal Rocket. Real thermal rockets are likely to only be 70-80% efficient, so your ACTUAL thrust-gains are likely to be as follows (assuming 75% efficiency)

1000 seconds: 494.265 kN extra Thrust

700 seconds: 709.0875 kN extra Thrust

500 seconds: 988.5225 kN extra Thrust

Now *those* numbers seem a little more reasonable... However what of the reactor-power required to get the Hydrazine to 3000 K in the first place?

Well, here's where I'm going to leave the door open to you guys- could somebody actually find the Specific Heat Capacity of Hydrazine for me? I searched and searched and searched, but I couldn't find a good metric measurement of the specific heat capacity anywhere- just a couple measurements in imperial units (btu of heat?) that I wasn't very sure of the reliability of anyways...

The basic principle from here is that 100% of the heat to reach 3000 Kelvin in the first place has to come from the nuclear reactor. This is made more complex by the fact that the Hydrazine starts as a liquid, then turns into a gas, and THEN dissociates into Nitrogen and Hydrogen gas... So, I will need both the liquid and vapor Specific Heat Capacity values for Hydrazine...

Just a note, the energy required to heat a ton of Hydrazine to 3000 K should probably be quite a bit greater than the energy obtained from its decomposition. It is the relative value of the two that will tell us how much extra Thrust we get from the decomposition of Hydrazine, however...

Regards,

Northstar

[FreeThinker]

Most of the Hydrazine would disintegrate, yes. The key word is "most". Hydrazine is so highly toxic that even the tiny amount that didn't get broken down by the reactor would be enough to make the launch site toxic to breathe near for days afterwards..

Still, with the right precautions it's acceptable considering is potential performance. Note I already added Hydrazine to the list of Propellants on the OP and made some conservative estimations based on other propellant performances. Based on the molecular mass, we know the Base Isp Multiplier of Hydrazine is 0.25. For the Thrust multiplier I took the highest single propellant Multiplier which is 2.2 and multiplied it with Hydrazine Base Isp to get a effective Isp of 0.55 . It's probably a lot higher but as I said I want to be conservative. Now the remaining question is, why wasn't Hydrazine mentioned as a NTR propellant anywhere? Besides the Toxicity, which just makes it more expansive, the real problem might be a technical/risk issues. In contrast to other propellants, it's not as stable. Perhaps it can spontaneously react even before reaching the combustion chamber, which would result in catastrophic failure!

Just try to Imagine 100 Ton Hydrazine tank exploding next to a thermal ncuclear reactor, it would be an very effective dirty nuclear fuel poison bomb

Would that be enough to make your nervous?

Edited March 23, 2015 by FreeThinker

[FreeThinker]

Well, here's where I'm going to leave the door open to you guys- could somebody actually find the Specific Heat Capacity of Hydrazine for me? I searched and searched and searched, but I couldn't find a good metric measurement of the specific heat capacity anywhere- just a couple measurements in imperial units (btu of heat?) that I wasn't very sure of the reliability of anyways...

Well a good source I found was Artemis Project: All about Hydrazine It mentions the following

Hydrazine's specific heat capacity is 25.23 g-cal/mol-deg (compared to water at 18), its specific heat of fusion 3.025 kcal/mol, and of vapourisation 10.2 kcal/mol, both much lower than water.

Anything usefull?

Edited March 23, 2015 by FreeThinker