How to make hydrogen rocket sustainable?

[Memphiss]

Hi,

I manage to make liquid hydrogen and launch an hydrogen rocket. But i found out that it must consume near 27 000 kg (27 tiles) of water to fill the 3 hydrogen tank of the rocket.

Is there a way to make hydrogen rocket sustainable?

[Coolthulhu]

Have gorillion geysers.

Launch the rocket from long silos and condense the resulting steam.

Don't fly to far away planets and only take as much fuel as you need using the rocket calculator app https://forums.kleientertainment.com/forums/topic/96933-rocket-calculator/

 

[ruhrohraggy]

2 hours ago, Memphiss said:

Hi,

I manage to make liquid hydrogen and launch an hydrogen rocket. But i found out that it must consume near 27 000 kg (27 tiles) of water to fill the 3 hydrogen tank of the rocket.

Is there a way to make hydrogen rocket sustainable?

Short answer : A geyser with good output, the more the merrier. 2-3 high output water geysers would be more than enough...

Long answer : It's actually not that bad crunching the numbers.

What do you need 3x fuel tanks full of hydrogen for anyway? Are you doing 110k km missions with 2x cargo bays? Most people have reported (and I feel the same) that the long distance missions aren't really all that worthwhile at the moment. They don't offer enough incentive, because Klei are mean, and make us cry to get what we want...(Or they have something else in mind that we just don't know about yet)

To sustain the farthest mission with 2x cargo bays, which would require 3x full tanks, would require the 2,700 kg liquid hydrogen. If you are not burning any of the hydrogen or exploiting from a single electrolyzer, you are getting 112 g/s hydrogen, which would require 24,107kg of water / 33 cycles to reach that total of 2,700kg H2.. (This would require 2x electrolyzers running for 21 cycles)

And that comes out to roughly 730kg of water added to your map per cycle to be sustainable...

So the easy way is to see if you have enough water producing geysers to hit or exceed that number...I can only use my map as an example for how much water I get...

I have 1x Cool slush Geyser erupting at 9.8 kg/s, for 138s every 368s. It is active for 67 Cycles, Every 114.5 Cycles.

Doing the math, it is active 37% of the time, and erupts for 37.5% 27.3% of that time. So 9.8 kg/s * 0.37 * 0.27 = 1.36 kg/s 0.979kg/s total average over the 181 cycles That comes out to ~ 587 kg / cycle average. So this one cool slush geyser is not enough to sustain a hydrogen rocket, at max range, with 3x fuel tanks and 2 cargo bays.

But I also have a water geyers @ ~ 1.2 kg/s average, and 2x cool steam vents at around 0.67 kg/s combined average. So I think the rest of that would make it sustainable :D.

 

39 minutes ago, Coolthulhu said:

Don't fly to far away planets and only take as much fuel as you need using the rocket calculator app https://forums.kleientertainment.com/forums/topic/96933-rocket-calculator/

 

I was going to link this as well. That app is so handy. Tunderlock is such a bro.

[Lilalaunekuh]

7 hours ago, ruhrohraggy said:

Are you doing 110k km missions with 2x cargo bays?

Ok just to feed my curiosity:

I done some math considering 3/5 fuel tank setups using 2 cargo bays, but I couldn't find any setup to reach a 100.000km planet using 2 cargo bays.

=> If you got one please post it

PS: If we want to calculate max efficacy for your sustainable rocket we should talk about setups using  4 hydrogen fuel tank and 1 liquid oxydizer tank.

=> Max potential hydrogen consumption would be:

3600kg hydrogen used over 30,5 cycles (30  sek added to the fueling time to make calculations easier and run your start automation for gantry/bunker doors)

3600kg / 30,5 cycles = 118,032 kg (hydrogen / cycle)

118032g (hydrogen / cycle)  / 112g (hydrgen) * 1000g (water) = 1053,857 kg (water / cycle)

=> You need an output of ~1,75 kg / s to keep your rocket working at max efficacy not efficiency

 

[ruhrohraggy]

30 minutes ago, Lilalaunekuh said:

Ok just to feed my curiosity:

I done some math considering 3/5 fuel tank setups using 2 cargo bays, but I couldn't find any setup to reach a 100.000km planet using 2 cargo bays.

=> If you got one please post it

PS: If we want to calculate max efficacy for your sustainable rocket we should talk about setups using  4 hydrogen fuel tank and 1 liquid oxydizer tank.

=> Max potential hydrogen consumption would be:

3600kg hydrogen used over 30,5 cycles (30  sek added to the fueling time to make calculations easier and run your start automation for gantry/bunker doors)

3600kg / 30,5 cycles = 118,032 kg (hydrogen / cycle)

118032g (hydrogen / cycle)  / 112g (hydrgen) * 1000g (water) = 1053,857 kg (water / cycle)

=> You need an output of ~1,75 kg / s to keep your rocket working at max efficacy not efficiency

 

I use this handy little app https://oni-assistant.herokuapp.com/

Select Hydrogen Engine

Select 2x Cargo Bay

Select 1x Liquid oxidizer

Select 3x Liquid Fuel Bay

Set slider to 2,200 (It's actually 2,200 LH2 for 110,000+km, I was just going with ops numbers for giggles)

Receive math :

Dry mass: 5,100
Wet mass: 4,400

Base distance: 175,560
Weight penalty: -63,376
Net distance: 112,184

?????

Winning.

[Lilalaunekuh]

56 minutes ago, ruhrohraggy said:

Wet mass: 4,400

That was my mistake all along. Thank you for helping.

When I read liquid oxydizer got 133% efficiency I always used 75% the oxidzer mass for my calculations.

(So liquid oxydizer was for me just loose 1/8 of the wet mass so your weight penalty kicks in later)

=> Always load 1:1 fuel to oxydizer and just travel further

 

So just 1900 kg of liquid hydrogen would be needed

 

[ruhrohraggy]

@Lilalaunekuh Glad to be of some help. (Even if I just quoted the app :P)

Also, I feel the rocket interface is extremely lacking in information. Having to resort to hard math or an app to figure out what's going on isn't very good game design imo.

They should implement their own little interactive slider that gives you feedback on the current rocket system in game.

The slider would be simple, as much fuel as the rocket could handle. It then adjusts the amount of oxidizer needed, and outputs a potential distance.

I'm all for making things harder...but I don't think this helps out new players at all, and is a rather big turnoff to rockets. Can't just balance a game like this for hardcore math-addicts.

[nvzboy]

I'd like to point out a thing when considering the sustainability of a hydrogen rocket. In some of the calculations here some of us calculate what a geyser would be able to do considering only the hydrogen, ignoring the fact that hydrogen is the byproduct of oxygen production, emphasis on byproduct.

The only other use for hydrogen is to burn it for power in the hydrogen generator. If you can replace the power you would normally gain by burning it with other means you are essentially losing nothing to feed that rocket its supply of hydrogen. The real bottleneck in terms of sustainability is its oxygen requirement as this actually competes with other uses and most of which can not be sustainably produced through other means than electrolyzing water.

[Lilalaunekuh]

1 hour ago, nvzboy said:

The real bottleneck in terms of sustainability is its oxygen requirement as

Water

Let´s say we don´t burn hydrogen for power and would always safe the same amount of oxygen.

=> A electrolyzer produces 776 g/s oxygen your not able to use as rocket fuel

(I use my unused oxygen to "cool" some buildings before venting it into space.)

 

[Sigma Cypher]

@ruhrohraggy you're such a nerd.  I love you man.

Does anyone know for sure it acts like the bottom (ruhro's assumption) instead of the top?  I don't feel like watching a geyser long enough to find out ...

[Saturnus]

It's the top one.

Geysers are active for a number of cycles (out of) every number number of cycles.

So for example a geyser that is active for 30 cycle s (out of) every 100 cycles is active 30% of the time. 

The same goes for eruption period.

And yes, I have tested it but you don't even need to. It states the next dormancy period when analysed so it takes but a glance to confirm it.

[Sigma Cypher]

OK so that's 1290 kg/cycle with a cool slush geyser and enough to support almost two of these max range rockets.  Sweet!  Never again will I self-power a SPOM though.

@Lilalaunekuh can you say more about "max efficacy?" Does that mean you tend to make all your rockets like this? 

My latest thought is to find the first asteroid with trace amounts of fullerene and just farm that until I have enough supercoolant ... then just declare victory.  I don't see the point of the more advanced materials if I can already make everything I need without them.  But I don't have a clear vision of the end-game because I am just starting.  For example, I don't know what to do with the sight-seeing module.  SpaceX is making one so it must be cool though.

signed: Elon Musk fan boy

edit:  I've seen people mention 8+ research modules.  I thought I got 50 research points per module per un-investigated thing on the planet (out of 5), and then I could use up to two more to identify the mystery resources.  So any more than 7 research modules (usually 6) would be wasted, right?

[ruhrohraggy]

1 hour ago, Saturnus said:

It's the top one.

Geysers are active for a number of cycles (out of) every number number of cycles.

So for example a geyser that is active for 30 cycle s (out of) every 100 cycles is active 30% of the time. 

The same goes for eruption period.

And yes, I have tested it but you don't even need to. It states the next dormancy period when analysed so it takes but a glance to confirm it.

That how it works then? Obviously it had to be one or the other, but I've never watched it. I took the more pessimistic approach to be safe without knowing for sure. Can you logically jump to that conclusion by just glancing at a snapshot of the next activity or dormancy?

My tired strung out brain didn't think so at the time...but I can be poor at making good assumptions some time...

Spoiler

See, to me...I would see next activity 8.9 cycles....But Since I've not been paying attention to it...I'm not really sure if it was dormant for 84.5 cycles, or 32.6...So I'd have to wait for it to be come active and check it's next dormancy to confirm right?

That and the wording of it isn't clear. 51.9 cycles, every 84.5 cycles...If they wanted to be clear, it would be 51.9 cycles out of every 84.5 cycles...but probably couldn't fit all that in there.

Anyway...not that I didn't/don't believe....This confirms it as far as my over-thinking brain is concerned...I managed to catch one of my water geysers right as it made the transition.

Spoiler

Thanks for the info. I am clearly still learning.

[Saturnus]

Naturally if that specific case you need to know when the current activity stops. After that 51.9 cycles it'll switch to saying: "Next activity: 32.6 cycles".

[ruhrohraggy]

11 minutes ago, Saturnus said:

Naturally if that specific case you need to know when the current activity stops. After that 51.9 cycles it'll switch to saying: "Next activity: 32.6 cycles".

Yeah, I added that in there. I woulda had to wait and watch it. Unfortunately, at the time I made my original math wall...most of my geysers were 30+ cycles out from any sorta change...So I said screw it and ignorantly forged ahead, but at least I did so knowingly, with the more pessimistic assumption. :P.

[Memphiss]

On 15/12/2018 at 6:51 PM, Coolthulhu said:

Have gorillion geysers.

Launch the rocket from long silos and condense the resulting steam.

Don't fly to far away planets and only take as much fuel as you need using the rocket calculator app https://forums.kleientertainment.com/forums/topic/96933-rocket-calculator/

 

Do you think the sum of the resulting steam is equal to the water consumed? I should mesure that if nobody already did.

[Coolthulhu]

12 minutes ago, Memphiss said:

Do you think the sum of the resulting steam is equal to the water consumed? I should mesure that if nobody already did.

No, it's not dependent on it. The output rate is constant or dependent on launch phase (probably constant).

You can actually get more than you put in if you send rockets to 10k planets and collect most of the output.

[Lilalaunekuh]

3 hours ago, Sigma Cypher said:

"max efficacy?"

Means increasing the possible yield for each rocket trip

=> I tend to add modules till my rocket would need more an additional fuel tank

 

Additional modules need an increasing amount of fuel when added to an existing rocket.

Considering the time it takes for a rocket to return I prefer to waste (renewable) fuel and do less trips.

=> Less resource but more time efficiency

 

 

3 hours ago, Sigma Cypher said:

Does that mean you tend to make all your rockets like this? 

Yes, even on early steam rockets I like to add additional research modules if I don´t already need a full fuel tank.

(PS: For a long time I used a 13 research module rocket to farm a planet in 10.000km distance, but only the first 5 modules will give additional data banks and that just on the first trip.)

 

3 hours ago, Sigma Cypher said:

and then I could use up to two more to identify the mystery resources.

The question marks are no "additional" research targets, so everything above 5 modules will result in diminishing returns.

 

55 minutes ago, Coolthulhu said:

The output rate is constant

Seems so.

Build you a big rocket silo ( = "build your rocket deep down inside your asteroid" ) to increase the distance your rocket travels in a non vaccume area.

=> You increase the useable steam/CO2 ouput