Stock fairings: Procedural or not?

[cpast]

"The issue is *development* cost, which is huge."

yes. they have the materials set, the structure set, they just have to modify the look of it on paper and all the rest is production. there is nothing cost HUGE on it. its marketing. and ESA pays for it (well, not the agency itself, but as i've said the governments funding ESA) arianespace is a company, a multinational company and they are selling these changes to those governments through ESA. business is a complex thing. far more complex than engineering.

They need to redesign the structure to support the increased weight and loads. They need to evaluate the effect of that on the rest of the rocket. They need to reevaluate separation systems, consider how payload will be supported in the new fairing, consider what materials are suitable, and run lots of simulations and tests. The personnel involved are highly skilled, and such people don't come cheap. They then need to re-tool production systems (production lines are optimized to produce a single thing of a single design; they are not flexible, and you need to change them when changing the design of what you're making). You can't just scale a system up and expect it to work; KSP allows that because "worry about internal structure of your parts" is out of KSP scope, but it doesn't work in real life. Real rocket science is quite a bit more involved than "slap another 5 meters on it and call it a day."

You don't seem to understand the relationship between ESA and Arianespace. ESA is in charge of the Ariane project. It's a pan-European project. They give significant support to Arianespace, not in the form of contracts, but in the form of direct financial support. ESA literally pays a subsidy to Arianespace solely to support them financially. ESA isn't paying this cost so they can use the fairing. They spend money on Ariane so Arianespace can provide a European launch capability. Similar things happen with Airbus. To call Arianespace just a company selling to ESA is simply untrue, because simple contractors aren't paid substantial direct subsidies to enable them to stay in business. The ESA is paying for development of Ariane improvements for the commercial launch market. They aren't buying 100 million euro fairings, they're spending 100 million euros so that future Ariane rockets can better support commercial launches.

Edited January 28, 2015 by cpast

[tater]

In KSP we do none of that. We slap it on, and if it works, we don't have exploding wreckage. The same massive planning, simulation, and testing you refer to would in fact apply to every single aspect of rocket design that in KSP is not a thing. It's a non-argument, IMO.

Real fairing sizes, to the extent they are not in fact arbitrary standardization are set by AERODYNAMICS. That is what should set them in KSP. If the atmosphere of Kerbin allows ridiculous fairings, so be it, that's where not following reality takes you.

What are real issues with fairings? Cross sectional area… maybe moving the CM lower due to empty space on top?

[cpast]

In KSP we do none of that. We slap it on, and if it works, we don't have exploding wreckage. The same massive planning, simulation, and testing you refer to would in fact apply to every single aspect of rocket design that in KSP is not a thing. It's a non-argument, IMO.

Real fairing sizes, to the extent they are not in fact arbitrary standardization are set by AERODYNAMICS. That is what should set them in KSP. If the atmosphere of Kerbin allows ridiculous fairings, so be it, that's where not following reality takes you.

What are real issues with fairings? Cross sectional area… maybe moving the CM lower due to empty space on top?

The thing is, a common argument for procedural fairings is "it's realistic, because while space agencies can't customize a new engine for each launch, they do just build a new fairing per payload." That's an argument I've seen a *lot* for procedural fairings - people who admit that real space agencies use standardized parts for most things, but think it's more realistic to have them custom-making fairings. It's also totally wrong. That's how we got on this topic in the first place.

(Also, the standardization of fairings is not arbitrary, it's because it's hugely expensive to design a new one. While the exact size *is* somewhat arbitrary, the fact that you have a short list of fixed fairing sizes for a rocket is not.)

[SaturnV]

So if i want to launch a mega candy donut of 9mt in diameter i have to use a Saturn V? :D

NO! I‘m not taking that thing!

[Tuareg]

They need to redesign the structure to support the increased weight and loads. They need to evaluate the effect of that on the rest of the rocket. They need to reevaluate separation systems, consider how payload will be supported in the new fairing, consider what materials are suitable, and run lots of simulations and tests. The personnel involved are highly skilled, and such people don't come cheap. They then need to re-tool production systems (production lines are optimized to produce a single thing of a single design; they are not flexible, and you need to change them when changing the design of what you're making).

yeah, it was working like that around the 18th century... today you can launch a new design into production in hours...

You don't seem to understand the relationship between ESA and Arianespace. ESA is in charge of the Ariane project. It's a pan-European project. They give significant support to Arianespace, not in the form of contracts, but in the form of direct financial support. ESA literally pays a subsidy to Arianespace solely to support them financially. ESA isn't paying this cost so they can use the fairing. They spend money on Ariane so Arianespace can provide a European launch capability. Similar things happen with Airbus. To call Arianespace just a company selling to ESA is simply untrue, because simple contractors aren't paid substantial direct subsidies to enable them to stay in business. The ESA is paying for development of Ariane improvements for the commercial launch market. They aren't buying 100 million euro fairings, they're spending 100 million euros so that future Ariane rockets can better support commercial launches.

or you dont seem to understand business models built on governmental lobby but we've got very far from procedural fairings

[Vallius]

As long as procedural fairing's don't allow completely ridiculous geometries, I'm all for that. We already have procedural engine fairings, but It'd be great if I could choose larger covers for tiny engines in a stack.

[tater]

The point is that if you want standard fairings, why shouldn't the player design them?

[Bill Phil]

The point is that if you want standard fairings, why shouldn't the player design them?

The players didn't design the engines, or the tanks, and everyone is pretty happy about that.

[tater]

Fairings are entirely different, as they enclose meta-parts entirely designed by the player.

[Pthigrivi]

I mean there's some basic physics to low-diameter>low-drag. I'm precise and smart and I can live with and work with that. I legitimately do think though there's an extra design constraint there which I've worked with in cargo-bays and KW fairings which is conforming to a standard. Its a preference and subjective but I happen to find it drives me to better design. I tend to keep landing gear and wheels and landing engines all within close tolerances and I have to think pretty deeply about mass symmetry and torque leverage and launch cost-efficiency. There's space which is visible to the designer to With procedural fairings there's just too much leeway, you can do whatever the bunk you want and zoop! its fine. It's actually worse than that its easier to make inefficient payloads, its that you can make inefficient payloads and not know it. Its an interesting question, but I think the fairest description is one of ease-of-use vs design transparency.

[Bill Phil]

Fairings are entirely different, as they enclose meta-parts entirely designed by the player.

So....?

You're limited in the size of the WHOLE vehicle in career mode. No one has too many problems with that. (It'll be a very small limit in Tier 0)

[tater]

Yeah, I don't disagree, as again, it doesn't alter any of my designs all that much. We are limited in a sort of broken way, however, by KSP. Look at rovers. Look at the real LEM. That's not possible in KSP, and you have to design an absurd contraption to land a rover. If you hang it on the side, you better hang 2 for balance. Now you have a lander that might well fit in a fairing for a 2.5m base… but not with 2 entirely assembled rovers hanging off the side. I should not be compelled to launch rovers then have to dock with them in space, that's just nuts.

As an example, set a few "standard sizes, then see how that works for actual designs. Might not affect all of us, just playing devil's advocate.

[Leszek]

I think that the fairings should be procedural. Though I appreciate that getting things to fit in standard sizes is a fun challenge for many I have two reasons why this shouldn't apply to stock:

1: Right now you can build all sorts of things, the sky is the limit. Fixed size fairings would hold back those that just want to build huge fun machines. Not everyone plays for realism.

If you play for halfway realism then:

2: IR is not stock. If you don't have movable joints, it is hard to fold up stuff so that they fit inside fairings. NASA, ESA, and the others can fold up stuff like origami if they need to, to make it fit. We can't, or more accurately our options are much more limited. If we had some basic movable joints than I would be just peachy with fixed size fairings.

My two cents.

[Pthigrivi]

I should not be compelled to launch rovers then have to dock with them in space, that's just nuts.

It's no big thing. Just package a big bus with a docking port on the roof at the COM. Once in orbit drag doesn't matter, flip that stuff around and crane it down.

[Bill Phil]

Yeah, I don't disagree, as again, it doesn't alter any of my designs all that much. We are limited in a sort of broken way, however, by KSP. Look at rovers. Look at the real LEM. That's not possible in KSP, and you have to design an absurd contraption to land a rover. If you hang it on the side, you better hang 2 for balance. Now you have a lander that might well fit in a fairing for a 2.5m base… but not with 2 entirely assembled rovers hanging off the side. I should not be compelled to launch rovers then have to dock with them in space, that's just nuts.

As an example, set a few "standard sizes, then see how that works for actual designs. Might not affect all of us, just playing devil's advocate.

Just build it taking into account the fairing limit. Pretty easy to do, really.

[tater]

So now I have to have bizarre design limitations in the other direction (more, rather than less absurd). No, I want Apollo 15-17. A small, 2 man rover, and a 2 man lander. So I have to do some absurd dock with rover maneuver(s) because a slightly larger fairing is not realistic or constraining enough?

- - - Updated - - -

Just build it taking into account the fairing limit. Pretty easy to do, really.

What is the fairing limit? Do you chose? such that it is .1 m bigger than your own lander/rover design?

What are your suggested sizes? Are all landers now going to be one lander can, one tank below, and gear until you get a size 3 base?

[Pthigrivi]

Well no man. I mean all the apollo missions were pretty limited in scope. They already had to do docking maneuvers. If we go back and have to pack laboratories and habitation and all that there's an economic logic to packing it linearly to counter drag and then flip it horizontal to distribute weight on landing. Or you can go the other way--stack things vertically for landing and include a small buggie with a very short wheel-base. Either way seeing and considering the standard in the VAB only helps understand that trade-offs. If opaqueness is what they are after, modular standards only aid that.

[tater]

The point is the real rover folded up and was assembled/unfolded in situ. There are things we cannot do in radially conservative ways in KSP, sadly. The fact that docking is wobbly makes that less than desirable as well, and CM is always an issue.

What about other landers? Duna? Eve? Laythe? How wide is that 3.75m base fairing, again?

[Pthigrivi]

Eve has always been a challenge and I'm cool with it remaining so. You can rock Duna the same way you do the mun--launch a mobile bus and rotate it 90 degrees to the landing thrusters before landing or do a tall stationary base with a small bottom-loaded buggie. Ive done both. Laythe is crazy easy because of you can use air breathing engines to sky-crane.

[Duxwing]

Proof that Yoda has a forum account.

KSK was paraphrasing Shakespeare, not Lucas.

-Duxwing

[Daze]

And if someone want to make a ""stupid"" lander of 5mt? He can't because "hey there's restriction and it's more fun!1!"

[Jouni]

Don't forget that fairings aren't really necessary when playing with FAR. They're mostly an aesthetic choice that may make the rocket a bit more efficient and a bit easier to control. Unless new stock aerodynamics are much less forgiving than FAR, you can always launch the payload unprotected on a bit larger rocket, and start the gravity turn a bit later.

[Capt Snuggler]

As long as procedural fairing's don't allow completely ridiculous geometries, I'm all for that. We already have procedural engine fairings, but It'd be great if I could choose larger covers for tiny engines in a stack.

bingo. if the procedural size changes were done in .5m diameter increments I think everyone would be happy. if your payload is too big for the 1.25m fairing, it automatically jumps to the next diameter increment (and drag value). same would work for height. the prices would be easier to predict and you could reasonably assume they have a manufacturing process in place for each incremental diameter.

this way, you get standard sizes but also with less part count in the craft and the part list.

*EDIT*

for the people worried about 5m+ landers not fitting in to fairings etc. well yes, your designs are likely to change BUT hinges people, HINGES will save the day! We need more people asking about hinges and rotation joints in stock.

Edited January 28, 2015 by Capt Snuggler

[Daze]

for the people worried about 5m+ landers not fitting in to fairings etc. well yes, your designs are likely to change BUT hinges people, HINGES will save the day! We need more people asking about hinges and rotation joints in stock.

It's not a my example, i try to build the most realistic as i can so no problem with crazy payload on top of a stick. The problem came out when there's the majority of people who plays for fun and since Squad likes that kind of fun (hey ferram) it MUST be procedural fairings, even hinges would be enough to make it fun.

[cpast]

bingo. if the procedural size changes were done in .5m diameter increments I think everyone would be happy. if your payload is too big for the 1.25m fairing, it automatically jumps to the next diameter increment (and drag value). same would work for height. the prices would be easier to predict and you could reasonably assume they have a manufacturing process in place for each incremental diameter.

this way, you get standard sizes but also with less part count in the craft and the part list.

That actually makes a *lot* of sense. That way, there can be an advantage in squeezing out that 0.1 meters of diameter if it lets you use a smaller fairing, but you aren't *forced* to do so if you're willing to take the price hit of the next bigger one. Some form of procedural is likely necessary; this seems like a good balance.