What is the liquid fuel and oxidizer in KSP? And is it cryogenic?

[TeeGee]

Discuss.

I was looking to use CoolRocketFX on my KSP install when I began to question (again) whether the fuel in KSP is cryogenic... and if it was hypergolic as well.

Why did I assume they are hypergolic? Well in the game you have an infinite number of restarts, no boil off, tanks don't have insulation, engine flame is visible (hydrolox engines have invisible flames), and thrust of the engines is low.

I just need someone from SQUAD to come here and disclose to the rest of us in KSP lore what kind of fuel Kerbals use because this is going to drive me crazy.

[Pseudo Gold]

As far as we know the liqued fuel in KSP has no analog to an actual fuel used by any space program or company. It's a catch-all term for the fuel.

[SkyRender]

It also goes by the name Jeb's Coffee. They serve it in the Astronuat Complex. No wonder the crew's so jittery all the time.

[regex]

Magical faerie poop and magical unicorn poop. Although I've heard tell kerolox is probably the closest in density if you assume @5l per fuel unit. Also makes sense because jets.

Anyway, this is (one of the many reasons) why I don't play stock anymore.

[Renegrade]

Wasn't the fuel supposed to be "Explodium" or something like that? Not sure what oxidizer is called though.

[Gerandar]

I dont see the need for them to get all sciencey with the fuels it really doesn't matter at all from a gameplay standpoint it could be grinded up grass mixed with water for all I care.

[thadisjones]

If you want to read what may be the definitive "fun" book about rocket fuels, you should search for "Ignition" by John Clark (1972). It is exceptionally interesting for anyone with an interest in chemistry, engineering, or physics. Anyway, the logistics of fuel and oxidizer as presented in KSP doesn't really match up with the properties of any real chemicals. KSP fuel is apparently instantly hypergolic with oxidizer yet stable enough to function in every kind of rocket motor as well as being air-burnable. At any given temperature range it neither degrades nor freezes even over decades of storage, and always maintains extremely low viscosity, but without "sloshing" or vaporizing in a partially empty tank (although this could be an argument for magic insulation, not magic fuel). At the same time, it's available and economical enough that effectively unlimited amounts are available for bulk launches. So even WITHOUT considering energy/density calculations it is pretty obviously a magic chemical with no real world analogue.

Edit: I'm not sure if I'm allowed to distribute/link to the PDF of "Ignition" for reasons.

[regex]

Wasn't the fuel supposed to be "Explodium" or something like that? Not sure what oxidizer is called though.

"blutonium" or some other such nonsense. E: If you can find that old resources chart, it should have it. E2: Ah, it was "Propellium" and "Oxium".

I dont see the need for them to get all sciencey with the fuels it really doesn't matter at all from a gameplay standpoint

Well, see, it could matter from a gameplay standpoint, as Real Fuels will teach you. Different fuels have different properties, work in different styles of engines, and require different storage solutions. It's quite interesting and provides some additional considerations for spaceflight, and, consequently, the gameplay.

If you want to read what may be the definitive "fun" book about rocket fuels, you should search for "Ignition" by John Clark (1972).

<snip>

Edit: I'm not sure if I'm allowed to distribute/link to the PDF of "Ignition" for reasons.

Ignition! owns and is quite easy to find on the web. Edited February 18, 2015 by regex

[Gerandar]

"blutonium" or some other such nonsense.

Well, see, it could matter from a gameplay standpoint, as Real Fuels will teach you. Different fuels have different properties, work in different styles of engines, and require different storage solutions. It's quite interesting and provides some additional considerations for spaceflight, and, consequently, the gameplay.

Ignition! owns and is quite easy to find on the web.

Mods are not part of the game at stock so it only matters to people who are going to play with that mod, I mean if you want to add realism to a game that doesnt hand it self to realism that well go for it but it still doesn't matter to stock gameplay.

[r4pt0r]

applying realworld chemistry to this game is absurd in my opinion. Fuel works so I just use it.

Taking some liberties because its a game is fine. the sim part of the game works alright, and aero is being retouched. 100% realism is unnecessary.

Edited February 18, 2015 by r4pt0r

[dryer_lint]

Fuel and Oxidizer are enough for me. Jets use Liquid Fuel and rockets require oxidizer as well, that's it.

The part list is already cluttered. Do we really need more fuel types?

[Engineer of Stuff]

applying realworld chemistry to this game is absurd in my opinion. Fuel works so I just use it.

Yes!

10chr

[klgraham1013]

applying realworld chemistry to this game is absurd in my opinion. Fuel works so I just use it.

Taking some liberties because its a game is fine. the sim part of the game works alright, and aero is being retouched. 100% realism is unnecessary.

I don't know if I'd use the word "absurd" as we are using approximations of orbital mechanics and aerodynamics (soon). The simplification of fuels is fine by me, but I wouldn't fully write out a deeper look on the subject.

[Nemrav]

according to regex its realism or bust

me: meh, just one type works and in RO I just ended up using random fuels that sounded about right (hydrogen + oxygen) and it got me to orbit just fine...

Really, yes unrealistic, but when you have ~30 fuel types, it just ends up being that you can't be bothered.. And just makes KSP one step closer to a spread sheet game where you can't get anywhere without your second moniter, some basic calculus etc. to simply get something up there...

edit: srry Regex, but I've... well noticed you like realism a lot...... Let's stop this now.

Edited February 18, 2015 by Nemrav

[regex]

according to regex its realism or bust

Seriously, I make one comment about how different fuel types could add different considerations to gameplay , just like how Real Fuels does, and everyone jumps on the "REALISM SUCKS I PLAY A GAME" bandwagon. Chill out and maybe consider what I wrote in the context of the quoted post regarding gameplay.

It's like talking to a brick wall with you fanboys... Can't be bothered to come out of your little box if there's even a whiff of "OMG REALISM THE GAME IS GONNA BE HARD".

[LaydeeDem]

Really, yes unrealistic, but when you have ~30 fuel types, it just ends up being that you can't be bothered.. And just makes KSP one step closer to a spread sheet game where you can't get anywhere without your second moniter, some basic calculus etc. to simply get something up there...

lel.

KSP has always been like that. It seems easier now because the game/mods can calculate and display it for us. Just because the math is hidden behind a fancy interface doesn't mean it's not there.

Also, speaking of calculations; real fuels can and will automatically configure your tanks to the correct ratios. Right click "Show Tank GUI".

EDIT: I gotta add, we DID use spreadsheets back in the day.

Edited February 18, 2015 by Nutt007

[RobotsAndSpaceships]

yes unrealistic, but when you have ~30 fuel types, it just ends up being that you can't be bothered.. And just makes KSP one step closer to a spread sheet game where you can't get anywhere without your second moniter, some basic calculus etc. to simply get something up there...

You're joking right? I can run a full scale RSS/RO Mars mission, with literally just KER and a wikipedia page about phase angles.

- - - Updated - - -

applying realworld chemistry to this game is absurd in my opinion. Fuel works so I just use it.

It's already a game about orbital mechanics and rocket design, I see no reason not to apply it. Personally, I find realfuels to be fun, as you have a selection of different types of fuels that can be used for different purpose, making rocket design much more interesting.

Edited February 18, 2015 by RobotsAndSpaceships

[Specialist290]

Alright, ladies and gentlemen, can we please keep this discussion on the topic at hand, and not the faults (perceived or otherwise) we might see in one another's attitudes and play styles? Seriously, it's been getting out of hand lately, and not just in this thread. We don't want the whole "gameplay vs. realism" debate to turn into the same sort of issue "manual vs. autopilot" used to be all the time.

[r4pt0r]

Do we need to know if the batteries are lithium-polymer, or nickle-cadmium? no, they work fine as is.

The current fuel system works good, I see no reason to add a bunch of convoluted fuel options and systems.

[RobotsAndSpaceships]

Do we need to know if the batteries are lithium-polymer, or nickle-cadmium? no, they work fine as is.

The current fuel system works good, I see no reason to add a bunch of convoluted fuel options and systems.

No, because that's a very small mechanic that probably even the most advanced sims don't model. Actual fuels on the other hand, significantly affect the game, as they vary in ISP, thrust, cost, etc.

Didn't the old never-happening resource diagram have some names for LFO?

[r4pt0r]

this jumbled mess?

[RobotsAndSpaceships]

jumbled mess

Hold up right there.

[Brotoro]

Well, the aircraft fuselage tanks that held liquid fuel used to specifically say "Kerosene" on them, so I always took that to be the default... but you don't get the right amount of kerosene and LOX in the LFO tanks, given their sizes and masses. The contents of the LFO tanks comes closest to matching some hypergolic fuels from real life, but doesn't actually match any. They could contain kerosene and some storable oxidizer.

If I had my wish, Squad would make a choice as to what liquid fuel and oxidizer are that matches some real-world numbers. I'd prefer liquid methane and LOX (KSP tanks are overly heavy compared to real-world tanks, and this could be explained by lots of insulation so we don't need to worry about boil-off) myself, but I'm not picky. Jet engines can also be made to work with liquid methane, and methane can be found or manufactured on various celestial bodies. Once Squad did this, players wouldn't have to worry about the details (unless they wanted to), so it wouldn't make a difference to most people...but it would make the realism guys happier. Northstar1989, for example, has been advocating the possibility of folding a new fuel mix into the new balance of the improved aerodynamics and what delta-V is needed to get to orbit. So Squad could strike while the iron is hot! ...But I suspect they have too many irons in the fire at the moment to do this now.

[regex]

If I had my wish, Squad would make a choice as to what liquid fuel and oxidizer are that matches some real-world numbers. I'd prefer liquid methane and LOX (KSP tanks are overly heavy compared to real-world tanks, and this could be explained by lots of insulation so we don't need to worry about boil-off) myself, but I'm not picky. Jet engines can also be made to work with liquid methane, and methane can be found or manufactured on various celestial bodies. Once Squad did this, players wouldn't have to worry about the details (unless they wanted to), so it wouldn't make a difference to most people...but it would make the realism guys happier.

This is a really good idea.

[White Owl]

I find some of the fuel choices in Real Fuels greatly enhance gameplay. Some, but not all. And you can still play the game using a single fuel-oxidizer combo if you want, with the stats making more sense.

I figure the stock game uses some version of RP-1 and LOX. The fuel tanks are so heavy because they have unobtainium-derived insulation technologies, so good that they appear magical to us poor ignorant earthlings. And the engines' ignition systems came from an offshoot research branch from that same unobtainium project.