[0.23.5] Realism Overhaul: ROv5.2 + Modlist for RSS 6/30/14

[jrandom]

Regarding TACLS, there's a TAC_LS.cfg floating around the end of the TAC LS thread that I made and someone modified. You will also need to change the consumption rates in the LifeSupport.cfg file (in plugindata, created on first run with TACLS).

Make sure that consumption * density * 86400 matches tons/day use of each resource, and that

BaseElectricityConsumptionRate = consumption_for_pod_in_kW // a constant, no matter the number of kerbals in it

ElectricityConsumptionRate = consumption_for_each_kerbal_in_kW

Also for obvious reasons make sure that the total mass produced by the production rates equals the total mass consumed by the consumption rates

I've got my config straightened out that adds life support and a 1-day set of supplies to every module that supports crew, but only if it does not already have a life support module -- so anything that was added to FASA should stay unmodified. (I'll have to go dig up the original config I had and re-add that. )

So... is there a good resource I can look at for what mass the foodstuffs should have?

Edit: Food? 3.8 pounds (including packaging) per day per person. But water... I've been googling for an hour and still can't find any hard numbers on how much water an astronaut needs per day. You'd think that'd be easy to find! But no, all I get are really vague answers. Gah. Argh.

Edited December 12, 2013 by jrandom

[SFJackBauer]

Isn't that amount of food a little high? Oh nevermind its in pounds...

Even then astronaut food is much more nutrient-packed than an average meal.

http://ston.jsc.nasa.gov/collections/trs/_techrep/CR-2004-208941.pdf, on page 59, table 4.3.4 lists baseline values for one crewmember-day (CM-d). Its basically 0.62kg of food, 4kg of water and +15% of those values for packaging.

Or 1.36 pounds of food and 8.8 of water.

[jrandom]

Thanks! I shall update my numbers! (The food one was for shuttle missions, so that might explain the increase in mass.) Now I just need to figure out the mass-per-day values for excreted waste, waste water and carbon dioxide.

Edited December 12, 2013 by jrandom

[NathanKell]

jrandom: I thought consumption for TAC (like ECLSS) was in units per second? That's why your numbers were like that.

You also might want to look at the excellent Atomic Rockets: http://www.projectrho.com/public_html/rocket/lifesupport.php

SFJackBauer: that's for freeze-dried food, where ~1kg of that water is used to reconstitute it, IIRC. So, jrandom, you might want to do 1.62 and 3kg? Meh, who knows.

You can easily back-calculate those numbers: WasteWater should be a bit more than water, CO2 should be a bit more than O2, and SolidWaste should be a bit less, such that sum(rate*density) for each resource for waste equals sum(rate*density) for each resource for consumption. Unless these astronauts are kids and still growing, they'll excrete what they take in, more or less

[jrandom]

I was getting weird answers running the numbers so I fired up KSP, tossed a food container in there, looked at its wet/dry masses as well as how many units of food it contained. Turns out, the 'density' resource setting is in tons-per-day, so that's what I'm going to stick with. This also makes it easier to plan missions -- "how many days of food do I have?" instead of "I have X kilograms of food... how long wil that last me?". The second approach requires the player to constantly have some sort of list with them with the kilograms/days conversion values on it.

[jrandom]

Here's a question I've never had to ask before: what is the actual density of space food? Eg. how much food should I be able to cram into any container of a given volume?

[birrhan]

Sorry if this has been answered before, but how exactly do you make heatshields, um, work in RSS?

I am using: DRE, FAR, KW Rocketry, KSPX, Engineer, IonCross, and RSS

I've already rescaled the heat multiplier in the DRE config from 25 to 12. But I gather there's an RSS specific heatshield. I don't see it anywhere though.

[Zander]

After installing the realism overhaul There are no more flames on reentering space craft. But the heat shields are working properly and stuff seems to be burning up.

[BrickedKeyboard]

Can someone break down the current LS situation?

As I understand it, ECLSS murders performance and is currently unplayable, with most posts on the thread for that mod complaining of FPS loss.

TAC "works" but apparently is not using realistic numbers? (and it doesn't simulate electric power, although, at least it runs faster)

So if we want to use ECLSS, we have to deal with bad performance, and if we want to use TAC, we have to dig up a config file for it to adjust the numbers?

Does that sum it up? Have there been updates to ECLSS that fix the performance issues?

[jrandom]

I'm working on realistic numbers/volumes for TACL, along with a parts re-scale. The only piece of information I'm missing is physical food density in terms of kg/m^3.

The only downside right now is oxygen won't work correctly with MFS since I need to use a utilization value of >1.0 and that won't be fully supported until the next release of MFS.

If I can get a ballpark figure for food's kg/m^3, I can release the .cfg tonight for you to use.

[BrickedKeyboard]

I take it numbers from Atomic Rocket aren't good enough?

It gave the following numbers in kg/Liter. Since both liter and m^3 are volume measurements, you just multiply to convert. There are 1000 liters in one cubic meter.

Frozen meat and veggies : 375 Kg/m^3. "fresh" foods, 250. Dry/canned goods, about 500.

From handling MREs, I know from personal experience that dry foods are not that dense. Even if you removed the air from the MRE package, it will not have that much density. Another factor here is that I don't think it matters that much. Since volume is cubed, I don't think that current missions have to optimize for volumetric density so much as reducing the mass. If you make the payload section of your rocket slightly longer, it will only have minimal effects on the air resistance. (while, for a given rocket design, increasing the payload mass comes up against hard limits)

So I would pick the lowest of these numbers. Imagine a food storage pantry filled with stacks of compact MREs, with extra space around them so that kerbonauts can get to supplies at the bottom of the pantry.

[jrandom]

I take it numbers from Atomic Rocket aren't good enough?

Of course they're good enough? Are you mad? It's the Atomic Rockets site we're talking about, here!... I'm... just trying to do a bunch of things at once. Stuff is dropping through the cracks.

So I would pick the lowest of these numbers. Imagine a food storage pantry filled with stacks of compact MREs, with extra space around them so that kerbonauts can get to supplies at the bottom of the pantry.

Aaand... I don't see a mass-per-liter value for MRE's. I've never handled one so I can't guesstimate. Throw a number at me?

Edit: I guess I could go with the dry-foods density of 0.5kg / liter...

Edited December 13, 2013 by jrandom

[SFJackBauer]

I take it numbers from Atomic Rocket aren't good enough?

It gave the following numbers in kg/Liter. Since both liter and m^3 are volume measurements, you just multiply to convert. There are 1000 liters in one cubic meter.

Frozen meat and veggies : 375 Kg/m^3. "fresh" foods, 250. Dry/canned goods, about 500.

From handling MREs, I know from personal experience that dry foods are not that dense. Even if you removed the air from the MRE package, it will not have that much density. Another factor here is that I don't think it matters that much. Since volume is cubed, I don't think that current missions have to optimize for volumetric density so much as reducing the mass. If you make the payload section of your rocket slightly longer, it will only have minimal effects on the air resistance. (while, for a given rocket design, increasing the payload mass comes up against hard limits)

So I would pick the lowest of these numbers. Imagine a food storage pantry filled with stacks of compact MREs, with extra space around them so that kerbonauts can get to supplies at the bottom of the pantry.

The numbers are in accordance with the NASA document I linked last page. On page 56 table 4.3.1 it shows that in the space shuttle, for each crewmember-day 0.0048m³ and 1.76kg were used for food. Thus in 1m³ you could store 366kg of space shuttle food.

[jrandom]

The numbers are in accordance with the NASA document I linked last page. On page 56 table 4.3.1 it shows that in the space shuttle, for each crewmember-day 0.0048m³ and 1.76kg were used for food. Thus in 1m³ you could store 366kg of space shuttle food.

I am ashamed that I couldn't figure that out from the chart. I was looking right at it! I feel like a moron around you folks.

[jrandom]

Preliminary TAC Life Support Rescale and RO Settings

Sorry this took so long. There was math involved. And I still probably got some of that wrong. MFS won't be supported until v4 is officially released.

Additional_Configs.zip

This is my compliment of patches for RSS/RO and includes the TACLS config, along with automatic RO electric charge amounts and usage rates for any and all pods holding up to 12 crew members (minus life support energy, see ReadMe.txt), and some other rescaling pieces. Feel free to delete whatever you don't want.

Very Important TACLS Note

Because we all know how often included ReadMe.txt files are actually read...

There are two settings in TACLS that cannot be set through the use of MM .cfg files. The ReadMe.txt file has instructions on where to find these values (in-game, no editing of files!) and what to set them to.

Edited December 14, 2013 by jrandom

[BrickedKeyboard]

So, with MFS version 4, we will maybe be able to use alternate containers that look more realistic for cramming in our supplies for our astronauts?

[jrandom]

So, with MFS version 4, we will maybe be able to use alternate containers that look more realistic for cramming in our supplies for our astronauts?

Yep! I'll have to make sure they're stuffable into the next release of StretchyTank's service module tank, too. v3 of MFS doesn't work because I need to use a utilization value > 1.0. v4 should handle this.

Note that there is an alternate texture pack that makes most of the TACLS containers look quite a bit better than the regular textures.

[jrandom]

Speaking of not mathing well, I realized this morning that I had used diameter-squared instead of radius-squared in my cylinder volume calculations, resulting in containers holding a lot more stuff than they should. (Ultra-dense! Super-science! Bad physics!)

I've fixed this and re-uploaded the Additional_Config.zip linked to in my post above. The life support numbers are now more sane-looking.

[NathanKell]

jrandom: Cool! Try with the utilization value. See if anything breaks. If not, just use it.

(They're an issue with autofill, I think, but it may not matter in practice).

[eggrobin]

I may be misunderstanding something, but your electric consumptions for the recyclers seem to be all over the place (from reading the cfgs). The electrolyser needs a whopping 954 kW to sustain 8 crewmembers (one ISS Elektron unit sustains 3 to 4 and consumes ~1kW), while the water purifier uses only 3 W to sustain 8 crewmembers (for some reason, the one that sustains 16 crewmembers is half as efficient). Note that (with existing systems) CO2 to O2 cannot consume less than electrolysis for a given amount of oxygen, as both the Sabatier and Bosch processes produce water.

You might want to look at the the calculations I did on the TACLS thread (electrolyser and fuel cell, Sabatier and Bosch reactors), these are just linearly scaled performances for existing devices. Realistic masses can be found at http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/40487/1/04-3358.pdf.

[jrandom]

I may be misunderstanding something, but your electric consumptions for the recyclers seem to be all over the place (from reading the cfgs). The electrolyser needs a whopping 954 kW to sustain 8 crewmembers (one ISS Elektron unit sustains 3 to 4 and consumes ~1kW), while the water purifier uses only 3 W to sustain 8 crewmembers (for some reason, the one that sustains 16 crewmembers is half as efficient). Note that (with existing systems) CO2 to O2 cannot consume less than electrolysis for a given amount of oxygen, as both the Sabatier and Bosch processes produce water.

You might want to look at the the calculations I did on the TACLS thread (electrolyser and fuel cell, Sabatier and Bosch reactors), these are just linearly scaled performances for existing devices. Realistic masses can be found at http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/40487/1/04-3358.pdf.

I was pulling numbers from all over the place, calculations were flying around, blood was spilled. The CarbonExtractor part consumes so much electricity because it's directly converting co2 to o2 (eg. without consuming any other resource). Same for the water->o2+waste (hydrogen). I'll have to add some fuel cells for generating both water and oxygen, but that means we need a new hydrogen resource slot. I'll look into it. Right now those recyclers do what they do using just electricity and no other chemical components (which will have to be managed properly). Since this isn't my life support mod I didn't want to go and add yet extra resources (like hydrogen waste).

I definitely agree that these numbers and recycler technologies need to be hammered out into something a bit more sane.

Would it make any sense to use LiquidH2 as input for a fuel cell? (Not sure what to do with hydrogen waste. Vent it? Store it?)

Edited December 15, 2013 by jrandom

[eggrobin]

It is probably a good idea to abstract the Bosch reactor+electrolyser in a single part for now (this works in closed circuit as far as hydrogen is concerned, and the waste is indeed graphite), but the power consumption for that is on the order of 43 000 kJ for 840 g of oxygen.

Calculations:

9959 kJ to turn 1 standard kerbal day of CO2 into 0.232 standard kerbal days of H2O

51776 kJ to split 1 standard kerbal day of H2O

rescaling factor for O2: 1 big kerbal day = 840/429 standard kerbal days

(9959 kJ + 51 776 kJ * 0.232) * 840 / 429 = 43 000 kJ (rounded to 3 significant figures)

Edit: answer to the edit

Would it make any sense to use LiquidH2 as input for a fuel cell? (Not sure what to do with hydrogen waste. Vent it? Store it?)

H2 is complicated. I don't know of any instances where life support O2 or H2 were also used for propulsion (I think there are plans for that, but there are plans for just about everything), so I'm not sure they should be identified with the MFS/RF LiquidOxygen resp. LiquidH2.

Using it later on in a fuel cell might make sense if you need a really big battery.

Edited December 15, 2013 by eggrobin
Typo

[jrandom]

It is probably a good idea to abstract the Bosch reactor+electrolyser in a single part for now (this works in closed circuit as far as hydrogen is concerned, and the waste is indeed graphite), but the power consumption for that is on the order of 43 000 kJ for 840 g of oxygen.

Calculations:

9959 kJ to turn 1 standard kerbal day of CO2 into 0.232 standard kerbal days of H2O

51776 kJ to split 1 standard kerbal day of H2O

rescaling factor for O2: 1 big kerbal day = 840/429 standard kerbal days

(9959 kJ + 51 776 kJ * 0.232) * 840 / 429 = 43 000 kJ (rounded to 3 significant figures)

Assuming a not-100% return on oxygen, is this combined reactor correct?

@PART[TacCarbonExtractor]
{
    @MODEL
    {
        @scale = 1.25, 1.25, 1.25
    }

    @rescaleFactor = 0.8
    @title = Sabier-Bosch Reactor
    @description = A closed-circuit life support recycling module that runs CO2 through a water stage and back into oxygen.

    @MODULE[TacGenericConverter]
    {
        @conversionRate = 8

        @inputResources = CarbonDioxide, 1, ElectricCharge, 43000
        @outputResources = Oxygen, 0.9, false, Waste, 2.218, true
    }
}

[eggrobin]

Some of it is

It turns out that there is a bug in your CO2 density: A big kerbal day is 112 g, this should be 1.12 kg.

Using the corrected density, the amount of O2 produced makes sense. Bear in mind that the efficiency is more that 90%, as the theoretical maximum here would be ~0.969, the respiratory exchange ratio of your kerbals (the ones from TACLS have a respiratory exchange ratio of ~0.866, I guess they work less).

The amount of Waste should be 0.32407407407407407 to conserve mass.

The electric consumption looks good.

The name is inaccurate though: there is no Sabatier reaction (CO2 + 4H2 --> CH4 + 2H2O) going on here (It is also possible to run a closed circuit with the Sabatier process, but you need to pyrolyse the methane, CH4 --> C + 2H2, and I haven't done the calculations for that).

This is just the Bosch reaction (CO2 + 2H2 --> C + 2H2O, requires higher pressures and temperatures than the Sabatier reaction), coupled with an electrolysis (2H2O --> O2 + 2H2).

[jrandom]

Some of it is

It turns out that there is a bug in your CO2 density: A big kerbal day is 112 g, this should be 1.12 kg.

Using the corrected density, the amount of O2 produced makes sense. Bear in mind that the efficiency is more that 90%, as the theoretical maximum here would be ~0.969, the respiratory exchange ratio of your kerbals (the ones from TACLS have a respiratory exchange ratio of ~0.866, I guess they work less).

The amount of Waste should be 0.32407407407407407 to conserve mass.

The electric consumption looks good.

The name is inaccurate though: there is no Sabatier reaction (CO2 + 4H2 --> CH4 + 2H2O) going on here (It is also possible to run a closed circuit with the Sabatier process, but you need to pyrolyse the methane, CH4 --> C + 2H2, and I haven't done the calculations for that).

This is just the Bosch reaction (CO2 + 2H2 --> C + 2H2O, requires higher pressures and temperatures than the Sabatier reaction), coupled with an electrolysis (2H2O --> O2 + 2H2).

I've corrected the CO2 density order-of-magnitude problem (dammit, I know co2 is heaver than o2, why did I not spot that??), and updated the module to this:

@PART[TacCarbonExtractor]
{
    @MODEL
    {
        @scale = 1.25, 1.25, 1.25
    }

    @rescaleFactor = 0.8
    @title = Bosch Reactor
    @description = A closed-circuit life support recycling module that runs CO2 through a water stage and back into oxygen.

    @MODULE[TacGenericConverter]
    {
        @conversionRate = 8

        @inputResources = CarbonDioxide, 1, ElectricCharge, 43000
        @outputResources = Oxygen, 0.969, false, Waste, 0.3240741, true
    }
}

Right now there's no way to turn down the output of a recycler -- it's either always-on-full-power or always-off. To better support long-term missions, would it be better to have an array of recyclers that run at rates for 2, 4, 8, 16 kerbals instead of the current selection of 8 and 16? Or some other numeric progression? (This is one area where IonCross still beats TACLS -- you can tune your recycler for however many kerbals you need to support via right-click context menu.)