Developer Insights #17 - Engines Archetypes

[desert]

5 hours ago, Pthigrivi said:

Starting the game out with 3 different fuel types means 3 different kinds of engines, 3 different kinds of tanks,

Just don't make these fuels and engines available from the start. Make them an advanced tech, when the player is confident with other things. And tanks could have unlockable fuel options

[Pthigrivi]

On 12/18/2022 at 6:46 PM, desert said:

Just don't make these fuels and engines available from the start. Make them an advanced tech, when the player is confident with other things. And tanks could have unlockable fuel options

Well this is why I think it's not crazy to introduce fuel-switch tanks at the same time LH2 tanks come in with nuclear engines. It's a good opportunity to look at dry-mass and start thinking about vessels that never have to touch an atmosphere. We've talked a bit about pacing in the past. Im personally hoping the 'average player' (read, not newbie, not vet) can start sending their first interplanetary probes/vessels, building their first stations and colonies within 10-20 missions. Let's say those are an hour each from concept to design to completion. At that point you're really in the thick of it understanding larger scale launch vehicles, mass efficiency, and new fuel types. I really think it's worth keeping things as simple as you can up to this point so folks can get a good grip on all the other not-so-obvious basics--How do I steer and not flip over? What does a gravity turn look like? What engine should I use and when? How much fuel should I put on a given stage? How do maneuvers and dV work? How do I re-enter the atmosphere? How do I land in a vacuum? It's actually a real problem to introduce alternate fuel types and incompatible fuels, tanks, and engines at this stage, because it doubles and cubes the variables new players are encountering while they're guessing and testing. Methane planes are for sure a bit weird, but I think it's better than creating a bunch of "what tanks work with what engines" confusion in the first 10-20 hours of the game. 

Edited January 15, 2023 by Pthigrivi

[Pthigrivi]

On 12/16/2022 at 7:18 PM, Nate Simpson said:

(if you look at the details of our colony methane fuel factory, it's got Sabatier reactors, water electrolyzers, CO2 condensors, etc.).

Can we talk about how cool this is? I take it this is all one part, but it opens all kinds of questions about splitting production to make H2O and CO2 for greenhouses. Anyone who's read the Martian knows there are some really cool gameplay synergies possible here. We also know the plan is for water to be an additive for atmospheric MH engines. I know there's no confirmation but its got my hopes up

Edited December 19, 2022 by Pthigrivi

[Ryaja]

This was posted on Thursday, I just found out about this yesterday HOW?

[Drakenred65]

It was kept hidden.

 

that said, current gameplay with KS P in science mode kind of drags things out even on science at higher difficulty. Career can drag it out even more.

[Vortygont]

On 12/16/2022 at 10:48 PM, regex said:

I certainly hope we get switchable fuel tanks instead of a raft of individual tanks cluttering up the choices (and even more hopefully, this goes along with procedural tanks so we can create stuff with unique shapes). I recall coming back to KSP after a couple years and wondering why the nuclear engine wasn't giving me more delta-V; I forgot it only used liquid fuel, which also severely limited my aesthetic choices.

I support this statement, and I think it is obvious thought. I hope that devekopers thought about it and you will change not tanks, but fuels

[Frozen_Heart]

I really like the archetypes system. Consistent visual language will be important for helping new players learn the game. I also think that sticking to a single liquid fuel type like in KSP 1 is a good idea. The game is meant to be accessible to everyone, and not a hyper realistic spaceflight simulator like Orbiter.

I'm concerned that 1.875m parts seem to have gone. I know they were DLC, but to me they were by far the most useful part size. At the roughly half scale of KSP spacecraft, they were ideal for shuttle and SLS boosters, Soyuz replicas, and Falcon 9 stacks. Additionally, the labelling system doesn't even seem to leave room for them. SM and MD correspond to 1.25m and 2.5m parts. So what would 1.875m parts be labelled? 

[samhuk]

On 12/17/2022 at 7:28 PM, Vl3d said:

...be mindful about spending too much time on the ground, squabbling about fuel naming conventions....

Indeed

On 12/17/2022 at 7:28 PM, Vl3d said:

world building, adventure and discovery

KSP1 was never about world building (just like how Minecraft wasn't until extremely late and even then very tenuously with the End etc.),  and adventure = discovery, so I think we can boil it down to "few/no mods were to do with discovery". That isn't true. There are the large number of mods that increase "adventure/discovery" - Kethane (before KSP1 consumed it with "Ore"), life support mods, extra planets (as you mention), science mods, progression mods...The list is endless!

I feel like asking KSP to be about "story"/"world building" is just overloading the game. A game can't be everything. There's a reason why the base Minecraft game never got a world-building/story element added to it - the player creates the story and world!

On 12/17/2022 at 7:28 PM, Vl3d said:

they forget what the purpose of the base game is.

No game has one true objective purpose, as you imply. Perhaps it was word-choice though? If you meant "how it feels to play", then I totally agree. I'm not sure I even know what base KSP1 looks like. It's all but an illusion to me by now.

[magnemoe]

On 12/17/2022 at 1:18 AM, Nate Simpson said:

A couple of clarifications:

Methalox was chosen as our default fuel to serve the colony progression: ISRU is a major component of the midgame, and we felt that methalox was the best all-purpose fuel to speak to the harvesting->fuel creation pipeline (if you look at the details of our colony methane fuel factory, it's got Sabatier reactors, water electrolyzers, CO2 condensors, etc.). We're hoping, as usual, that if a person is interested in the process being demonstrated, they can hit Wikipedia and learn some cool stuff. 

Second, we haven't talked much about it, but +1 to the folks above who have pointed out that there will be another new fuel present for day one of Early Access: liquid hydrogen. When you see gold foil on tanks in any capture footage, that's what that is. The NERV and SWERV engines run on hydrogen.

So they run on LH2, makes sense, now H2 and O2 should be even easier to do ISRU on as you only need to melt and split water. 
Also remember we have monopropelant and ion engines, later is more useful with trust under warp, then we have metallic hydrogen I assume they come in orbital with higher trust but lower isp and the deep space version. 
Finally we have charges for orion pulse nuclear and fusion fuel. At least metalic hydrogen and nuclear bombs require factories to produce so chemical engines will stay relevant in the game. 

It makes sense to me to don't have many chemical fuels, their performance is not that different, however it makes some sense with some hydrolox orbital engines so you lander can use the same fuel as the nuclear transfer ship. 

Edited December 19, 2022 by magnemoe

[magnemoe]

On 12/17/2022 at 2:49 AM, Minmus Taster said:

I used it quite a bit for 3.5 meter stacks, you can add 1-2 vectors in the middle for more performance. 
If you saw the Artemis 1 recreation they used an 6 nodes engine plate with 4 engines for most of the same effect. 

[Vl3d]

34 minutes ago, samhuk said:

I feel like asking KSP to be about "story"/"world building" is just overloading the game. A game can't be everything. There's a reason why the base Minecraft game never got a world-building/story element added to it - the player creates the story and world!

On 12/17/2022 at 9:28 PM, Vl3d said:

they forget what the purpose of the base game is.

No game has one true objective purpose, as you imply. Perhaps it was word-choice though? If you meant "how it feels to play", then I totally agree.

The fundamental obiective is in my opinion to make you, the player, curious about space. Going deep into the details and learning about space/aero technology is emergent behavior.

I was not referring to "world building" as a character driven narration mechanic. I was referring to exploring the unknown, discovering a surprising universe / game world. Going out there!

That's what motivates me - the exploration element. This "universe building" needs a lot more effort and attention than KSP1 could afford. Searching for anomalies only to discover plain monoliths is just disappointing..

[Vortygont]

On 12/15/2022 at 9:44 PM, Intercept Games said:

I’ve put together some sketches of these four archetypes to guide our artistic design going forward. The goal is for each of them to have a distinct visual look that is preserved through all size classes, and is versatile enough that, for example, a Mainsail doesn’t just look like a smaller Mammoth. We can pick and choose from a number of reality-alike design elements to create cool, Kerbal-native engines.

Booster engine features and possible design variations

Will all booster engines look like this? As I understand right it will be more visually understandable that it is booster if it will have this gas generator tube. But not all booster engines have this construction, for example F-1 drive exhaust go around the nozzle, and RD-170, BE-4 and Raptor have closed engine cycle. I believe that player immediately or very quickly guesses that in the description of engine is its type (booster or other) and won't confuse the engines as often, and tutorial I think help player to distinguish engine types.  So the framework of what an engine looks like can be looser and we get a wider variety of engines

[SciMan]

The truth about methane not being used in jet engines IRL is that the statement is not as universally true as you might think.
In fact, it's only true if you only consider the "jet engines" that are attached to things that move, be that on land sea or air (gas turbines have been used for propulsion of all 3 types of vehicles, the M-1 Abrams uses a "jet engine" aka gas turbine, aircraft use jet engines, and even some fast ships use gas turbines to drive the propellers).

If you look at stationary jet engines (more commonly and more correctly called "gas turbines"), however, the situation changes drastically.
Look at just the stationary "jet engines" (like I said, and will entirely switch over to from here on out, gas turbines) you'll find that they're nearly universally fueled by, drum-roll please, Methane.

Liquid methane, gaseous methane, it's still the same stuff. Of course, in this context it's more often referred to as "natural gas" but that's just methane with impurities, so it's still the same stuff.
This is true in the same way that "Jet fuel" is the same as "Kerosene" is the same as "RP-1", at least on a gross overview level.
In the case of the US Military, this is leveraged to simplify logistics, the US military fuels everything on JP-4, yes even the HMMVWs and M-1 Abrams run on JP-4 aka "a military standard for jet fuel".

Point is, gas turbines used for power generation or on oil rigs to push natural gas into pipelines, they all run on METHANE!

The only problem left to solve for using it on aircraft is a storage problem, not a "how do you make the engines run on this stuff" problem, and since the fuel tanks in KSP 2 will hold Methane, it wraps that up quite nicely.

[Vl3d]

Also.. there are a lot of cars with bi-fuel engine conversions.

https://www.doityourself.com/stry/how-to-convert-your-car-to-run-on-natural-gas

[Cpt72Bug]

On 12/15/2022 at 12:44 PM, Intercept Games said:

There’s a lot of trial-and-error gameplay before you learn the hard-won lessons about specific impulse, thrust to weight ratio, and fuel density that can rocket you to success in KSP. Hah

Not going to lie, you can do the whole game with a single engine and a ton of boosters. The ability to build in orbit "docking" pieces together is how I get to planets. I think the fact you are addressing the elephant in the room is really good for healthy gameplay. It took me watching one of your teasers for KSP2 to realize that maybe I should have different engines for different missions. 

[T1mo98]

I have 2 questions;

1. Will part variants return? As much as I like how the engines look, I'd love variants without boattails, for example.

2. Will Making History or 1.875m parts and engines be added to the game?

Edited December 20, 2022 by T1mo98

[T1mo98]

On 12/19/2022 at 3:15 PM, Frozen_Heart said:

Additionally, the labelling system doesn't even seem to leave room for them. SM and MD correspond to 1.25m and 2.5m parts. So what would 1.875m parts be labelled? 

I think IM could work, standing for 'intermediate'

[TMS]

Why use imprecise and awkward labels (SM, MD , etc) for part diameters when their numerical originators exist?  How would future mods for custom diameters work around this? 

Also, the part variations added towards the end of KSP1 development were an absolute joy - especially when you realised you could combine a barebones variant of a 2.5m engine on a stack of 1.25m tanks without it looking odd.

[Frozen_Heart]

2 hours ago, T1mo98 said:

I think IM could work, standing for 'intermediate'

I was thinking the exact same!

1 hour ago, TMS said:

Why use imprecise and awkward labels (SM, MD , etc) for part diameters when their numerical originators exist?  How would future mods for custom diameters work around this? 

Also, the part variations added towards the end of KSP1 development were an absolute joy - especially when you realised you could combine a barebones variant of a 2.5m engine on a stack of 1.25m tanks without it looking odd.

I assume to make it easier for casual players who may not have a science or engineering background. Especially if they learnt using imperial units.

Hopefully the actual diameter is shown in the part details though.

[GigFiz]

On 12/16/2022 at 11:49 PM, Nertea said:

I do like playing Engine Selection Simulator myself...I made at least one KSP1 mod for that. 

Well this is the understatement of the forum. 

Seriously guys, if you want proof that this is something they are definitely thinking long and hard about and see it, and and other important issues discussed in depth, just go read Nert's old Dev thread, and the thread for his Cryo Engines; that's around 250 pages worth of relevant discussion and debate right there. We have a man on the inside, as it were, someone who has thought about all these issues and more and been here with us discussing them and making mods for years, who is now a part of actually developing KSP2. 

 

On 12/16/2022 at 11:49 PM, Nertea said:

Think of it as Kerbals taking a slightly different technical path to rocketry than humans.

This was definitely the direction my brain went with this debate. People are talking about "the way it really was", but this isn't a replica of humanity's space program, this is us guiding our happy LGM^TM through their own foray out into the galaxy; it is going to have similarities to ours, but there is no reason that it has follow the exact same path; it's not like Methalox isn't also perfectly viable fuel choice. And for jets, for one, that's not a big enough aspect to warrant a whole separate fuel. Besides, we don't make our jet fuel/avgas out of methane, but that's not because it isn't possible. Maybe Kerbin has less or harder to reach oil, but lots of easily accessible natural gas

And think of it this way, in addition to the fact that they didn't pick methane arbitrarily and the cool stuff that is coming from it that they have mentioned in this thread, the fact that they made it anything specific is still a plus for mods. In KSP, the nebulous "liquid fuel" made it so fuel mods had to decide what that actually was the equivalent of (though kerosene was the popular choice, but it didn't have to be) first. This way removes all the ambiguity and makes it easier for fuel mods to be more consistent/cross-compatible, as well as makes the nomenclature more consistent, by having all the fuels identified rather than having a split between 'real life' fuels and 'video game' fuel.

 

On 12/16/2022 at 7:55 PM, Bej Kerman said:

This is an over-reaction. If you really think labelling engines by their function is going too far, you could say the same thing about telling the player their thrust and efficiency and argue that players should only be allowed to know how powerful an engine is by testing it for themselves.

Heck, I'd say go one further than just labelling: I want them to actually sort them that way in the parts tab (not under different tabs, just subheadings dividing up the parts in the engine tab). Not only will this make it easier for brand new players as they design their first rockets, it would be a change in the visual language that would make it easier and faster to find the engine you are looking for, which would be a great thing for all of use, regardless of experience I love adding engines and other cool part mods, but dear lord do things get cluttered and time consuming just looking for the right parts in the VAB/SPH.

Also, many of the engines are already essentially labelled it's just that it's buried offhand in the description, or even just implied rather than stated. This is information the game was already trying to give us in KSP1, it's just going to be doing a better/clearer job of it now. Besides, they aren't fundamentally changing the way the engines work; a label won't prevent any 'off-brand' use of an engine that we can do now from being possible.

[GigFiz]

4 hours ago, Frozen_Heart said:

I assume to make it easier for casual players who may not have a science or engineering background. Especially if they learnt using imperial units.

Hopefully the actual diameter is shown in the part details though.

I mean that makes sense in the very early game, but KSP2 is going to go bigger, and then you add mods, it's gonna get a bit silly eventually. SM-M-LG works great when most stuff is 1.25-2.5-3.75, but when it gets to be .875->1.25->1.875->2.5->3.75->-5->7.5->10->? any sort of word based system (huge! giant!! massive!!! gigantonormous!!!! supercalifragilisticexpialibiggest!!!!!) is going to end up being more arbitrary and confusing than plain numbers. I think this could be a great place for tutorials to cross the gap: introduce new players with descriptives, then gently move them over to plain diameter. I don't think it would be a huge leap for people to make.

Also, I really hope there is a better part sorting system in place than what we have now. Not the tabs themselves, but a better, intuitive way to sort within tabs, especially for size. Being able to go to structural parts and then just hit 2.5m would be so nice; have it so if you also hit 3.75m, it will also show adapters between the two, and have an adapter button that would show all the adapters that connect to the sizes currently selected, etc. I very much in favor of things that make less time spent playing hide and seek for parts while you are designing stuff.

Oh, and for off-world VABs and such, an easy button to hide all the parts that you do not currently have the resources for.

Edited December 21, 2022 by GigFiz
grammar

[Minmus Taster]

Found this meme;

Once you hear it you'll never play KSP the same again...

[Catto]

I dont understand my monkey brain dont understand

[shdwlrd]

1 hour ago, Catto said:

I dont understand my monkey brain dont understand

Sometimes it's not even worth it to try. Some of the memes that get dug up are so far in the weeds in a subject, unless you know the subject matter intimately, you'll never understand it.

[The Aziz]

8 hours ago, GigFiz said:

Also, I really hope there is a better part sorting system in place than what we have now. Not the tabs themselves, but a better, intuitive way to sort within tabs, especially for size. Being able to go to structural parts and then just hit 2.5m would be so nice; have it so if you also hit 3.75m, it will also show adapters between the two, and have an adapter button that would show all the adapters that connect to the sizes currently selected, etc. I very much in favor of things that make less time spent playing hide and seek for parts while you are designing stuff.

One of the earliest showcases of VAB UI