[1.12.*] Deadly Reentry v7.9.0 The Barbie Edition, Aug 5th, 2021

[Starwaster]

Well, it should make considerations change the moment is clear the shape of the reentry pods have never been flat ones, but rather profiled (most commonly spherical sections at the bottom, where drag has effect). And the reason being the one I showed above.

It doesn't change anything with regards to a specified craft configuration that is not particularly stable nor with regards to whether or not I should go to any great lengths (as DRE's main modder - through part or DRE mod work) to make it stable.

• The game's stock aerodynamics does not think it is stable.
  
• FAR does not think it is stable.
  
• I do not think it is stable.
  

Whether it could become stable (as opposed to designing a different craft to be stable) is up to the player in general who might do so by deploying

• ballast?
  
• control surfaces or fins?
  
• RCS?
  
• shifting center of mass through allocation of resources in the craft? (maybe, not a lot to work with there)
  

In short it is not a mod design consideration which is how this situation has been presented to me and what guides my response on the matter.

Edited June 4, 2015 by Starwaster
clarification

[diomedea]

OK, my response to the above is clear then. This add-on is unrealistic.

The heatshields are flat instead of curved as they should be, therefore don't allow the dynamic stability shown in reality. Stock KSP tries to correct this through an artifact (as the center of pressure variance is not computed) so you may be considered right the stock aerodynamics doesn't. If FAR can't however, is only due to the wrong shape.

Note I'm not telling to change the heatshields models to make them spherical sections. After all this is your choice, as DRE's main modder, to have them credible or not. Sure they aren't now.

[Gryphon]

I don't know as much about this as the mod author, but the Atmospheric Entry article on wikipedia is quite interesting.

I don't know much about naval architecture, but from my one exposure, I recall that the modern bane of naval stability is high center of mass, often driven by the addition of equipment high on the superstructure after construction.

Oh, and Starwaster, I don't have a problem with overheating while going really fast during ascent - after all, that was a real world problem encountered by the X-15, which they countered by adding - you guessed it - ablative shielding. This allowed them to reach Mach 6.7.

Yes, it was pink.

[Starwaster]

OK, my response to the above is clear then. This add-on is unrealistic.

The heatshields are flat instead of curved as they should be, therefore don't allow the dynamic stability shown in reality. Stock KSP tries to correct this through an artifact (as the center of pressure variance is not computed) so you may be considered right the stock aerodynamics doesn't. If FAR can't however, is only due to the wrong shape.

Note I'm not telling to change the heatshields models to make them spherical sections. After all this is your choice, as DRE's main modder, to have them credible or not. Sure they aren't now.

It's not a question of whether the shield itself is right or wrong / stable or unstable. It IS stable if used in a reasonable manner.

The craft design that was presented for consideration is unstable. It was actually presented as being stable without the DRE shield but that is not the case. It is not a stable design.

(it's not a question of where he grips it...)

That's number 1.

Number 2: I inherited those shields along with the mod itself when I took it over.

Number 3: If you or anyone does not like the DRE shield then you have several options.

• Use the stock ones (A case was made that it allows that death trap that was posted to be stable. I don't care what 1.25m shield you put on that thing, unless you have something that broadens the base and lowers the center of mass then it is NOT stable and would never BE stable in real life. It is an unstable design. But if the stock shield makes it stable and that makes one happy then one should use the stock shield and be happy with it. But one should not expect me to believe that a small 1.25m shield is going to make that stack stable. Unstable design; period. Just in case anyone missed it: lower the center of mass or unstable)
  
• Go download alternate shield pack from the first post. I provided a few to choose from. Lost Oblivion. Very nice looking. NASA ADEPT shields (deployables to replace the broken inflatable that kept breaking worse and worse with each KSP update beyond my ability to repair).
  
• Go download a modeling program and craft some replacements. I will always take pull requests into consideration.
  

[diomedea]

Those are some good points.

1, sure not everything could be made stable. My considerations are worth for a correctly profiled craft, as the center of mass must lie below the center of curvature of the bottom.

2, I know you inherited those shields. And are nice shields also, but were working with a different aerodynamic model (both in stock, and with FAR). No surprise they can't work the same now, and sure is not your fault they can't. Sure they are a lot flatter than real ones, so the stabilizing effect has also to be much lower when correct aerodynamics are used.

3, good suggestions. Some of the alternate ones may work, have yet to try them. Or at least, I expect them to work with FAR and a correctly sized reentry vehicle, not anything. Without FAR, it may be the case to consider testing some offset, as KSP does, but that is not an action I would require you to take when you don't like it.

[Starwaster]

Here is the 1.25m heat shield in question. Sure LOOKS like it has a rounded bottom. About as round as Mercury was anyway. That's round enough for me.

More to the point however is the image below proving that yes, this shield is aerodynamically stable when used reasonably and realistically. The probe core is the OKTO2. It has no reaction wheels and no RCS were placed on the craft. That was a design oversight on my part. The vehicle hit its reentry interface sideways and oriented into the position you see.

So it is NOT flat, it IS rounded and it is stable.

Use it responsibly.

[Ryds]

Hello,

I don't think its reasonable to expect a craft that's 4 science juniors long to behave itself whilst crashing through the atmosphere at 2km/s. The space shuttle is the longest re-entry vehicle we've launched and that needs ablative shielding all along it and must follow a strict re-entry profile.

The craft flipping is annoying but as someone either in this thread or in FAR said, KSP is about engineering, so find an engineering solution to it.

Here's mine. I've used 4 A.I.R.B.R.A.K.E.S and placed them so that the don't cover the EVA hatch. To be honest I've got 50 mods including B9 so I'm not sure if these are stock or not or where they come in the community tech tree (I used sandbox to find something suitable).

When flat at launch they don't overpower the atmo stage wings, although I found I needed to add an extra pair (6 instead of 4) to make sure the CoL was low enough.

At re-entry I open them as soon as I hit atmo. I'm then able to descend using only SAS at a cost of 0.005 EC instead of retrograde hold @0.7 EC. You need to see it down manually tho as if you deviate from the vector indicator by more than a few degrees you'll go poof.

I'd suggest moving this lower down the tech tree, but I'm not a modder and don't know even how to do that. I'll post this in FAR too as a modder may want to pick it up.

Hope this helps, I'm pleased to finally offer a small solution for once instead of just reporting bugs!

[Starwaster]

Without FAR, it may be the case to consider testing some offset, as KSP does, but that is not an action I would require you to take when you don't like it.

The image I posted depicts a shield that IS stable precisely because I spent time adding CoP offset to the shield. I'm not refusing to make it stable, I've MADE it stable

- - - Updated - - -

Hello,

<proactive solution snipped>

Hope this helps, I'm pleased to finally offer a small solution for once instead of just reporting bugs!

http://i.imgur.com/LLsF4FW.png

A proactive solution.

Outstanding.

[Ryds]

T

A proactive solution.

Outstanding.

:)

[woot]

I tend to agree with Starwaster on this one, but am trying to figure out how best to handle re-entry in those rare situations when atmospheric instability is a necessity.

Won't those airbrakes burn up? I'm trying to land on Eve; I've done it a couple times but in both cases it was mostly luck. I use the big deployable ADEPT heatshield (after messing with the config file so it doesn't explode), but I haven't been able to keep things oriented properly. The center of mass is very low and the deployed heatshield is wider than the lander, but I think it's just too tall to want to be stable.

I might try airbrakes if that seems workable, and have also thought about figuring out how to stick another big deployable heatshield on the opposite end. For the sake of general discussion, what's the best way to handle atmospheric entry of an inherently unstable spacecraft?

[yardpup01]

I tend to agree with Starwaster on this one, but am trying to figure out how best to handle re-entry in those rare situations when atmospheric instability is a necessity.

Have you found SAS to be insufficient? I ask because I've landed a number of crafts consisting of Mk1 pod + science jr + 1.25m service bay + 1.25m heat shield. Definitely unstable. But I've found that stability assist is able to maintain stability of the craft as long as I keep it right on the retrograde vector. I should note this is with FAR and not stock aerodynamics.

[Ryds]

I tend to agree with Starwaster on this one, but am trying to figure out how best to handle re-entry in those rare situations when atmospheric instability is a necessity.

Won't those airbrakes burn up? I'm trying to land on Eve; I've done it a couple times but in both cases it was mostly luck. I use the big deployable ADEPT heatshield (after messing with the config file so it doesn't explode), but I haven't been able to keep things oriented properly. The center of mass is very low and the deployed heatshield is wider than the lander, but I think it's just too tall to want to be stable.

I might try airbrakes if that seems workable, and have also thought about figuring out how to stick another big deployable heatshield on the opposite end. For the sake of general discussion, what's the best way to handle atmospheric entry of an inherently unstable spacecraft?

They didn't burn up nope. Actually they hardly raised their temperature which leads me to think they are from a mod, not stock, checking...

I think they are stock, in squad/aero/airbrake. Does the heatshield produce an area behind it that doesn't heat perhaps, I'm thinking maybe it punches a hole through the air so the superheated air doesn't hit the airbrakes.

I reckon making aerodynamic changes to the vehicle is the way forward, especially when a low CoM is not enough to keep things stable. One other thing I tried was the suggestion that someone gave about using infernal robotics and folding a set of wings out from the top of the craft on a hinge. They didn't work so well, I found that the craft was more prone to flip when slightly off the ball and once it started to go things would happen very quickly with no chance to correct.

But I def think there's room for a modder to work with bac9 or the procedural wings guys to design a set of FAR/DRE airbrakes.

[Starwaster]

I tend to agree with Starwaster on this one, but am trying to figure out how best to handle re-entry in those rare situations when atmospheric instability is a necessity.

Won't those airbrakes burn up? I'm trying to land on Eve; I've done it a couple times but in both cases it was mostly luck. I use the big deployable ADEPT heatshield (after messing with the config file so it doesn't explode), but I haven't been able to keep things oriented properly. The center of mass is very low and the deployed heatshield is wider than the lander, but I think it's just too tall to want to be stable.

I might try airbrakes if that seems workable, and have also thought about figuring out how to stick another big deployable heatshield on the opposite end. For the sake of general discussion, what's the best way to handle atmospheric entry of an inherently unstable spacecraft?

They might, but it has an emissiveConstant of 0.95 so short of ablative shielding, they're pretty well protected. (that's an unrealistically high emissiveConstant IMO... 0.6 would be more likely)

What that means is that they reradiate a lot of the heat that they take in. It's a passive solution that's probably better for very shallow reentries like a spaceplane but that crazy high emissivity would probably let them survive.

[Svm420]

But I def think there's room for a modder to work with bac9 or the procedural wings guys to design a set of FAR/DRE airbrakes.

Do you all really believe that is how air brakes work or are intended to work? I honestly can't tell.

@Stawaster I would love for you to correct that horrible oversight by squad and fix that emissive constant if not I'll fix it in my game, but dang that is so cheap why even install DR if you are just going to use control cheat surfaces

[Starwaster]

Do you all really believe that is how air brakes work or are intended to work? I honestly can't tell.

@Stawaster I would love for you to correct that horrible oversight by squad and fix that emissive constant if not I'll fix it in my game, but dang that is so cheap why even install DR if you are just going to use control cheat surfaces

Aside from the near black body level of radiation it's not that far fetched. Certainly no more so than a balute and I just bet you'd love to see one of those in the game...

They didn't burn up nope. Actually they hardly raised their temperature which leads me to think they are from a mod, not stock, checking...

I think they are stock, in squad/aero/airbrake. Does the heatshield produce an area behind it that doesn't heat perhaps, I'm thinking maybe it punches a hole through the air so the superheated air doesn't hit the airbrakes.

I reckon making aerodynamic changes to the vehicle is the way forward, especially when a low CoM is not enough to keep things stable. One other thing I tried was the suggestion that someone gave about using infernal robotics and folding a set of wings out from the top of the craft on a hinge. They didn't work so well, I found that the craft was more prone to flip when slightly off the ball and once it started to go things would happen very quickly with no chance to correct.

But I def think there's room for a modder to work with bac9 or the procedural wings guys to design a set of FAR/DRE airbrakes.

All parts generated an occlusion cone but IIRC, the code is limited to stack mounted parts with surface mounted parts not receiving occlusion.....

Most likely reason why they're not heating up is that 0.95 emissive constant I mentioned. That's 0.05 short of a perfect black body radiator.

Edit: Ok, the ones you have in that picture are about half the size of the stock AIRBRAKES....

Edited June 4, 2015 by Starwaster

[Ryds]

Ah yeah, forgot to mention I tweakscaled them to fit.

[NathanKell]

Drag occlusion is stack only.

Occlusion for convection (or solar or body radiation) works on all parts. Short answer is anything behind a heat shield (in its direct shadow) will not get convective flux.

[Sokar408]

You accuse me of pride? That's rather insulting.

I think I made it very clear, that it to me from my perspective seemed like pride. I clearly and intentionally expressed it in a way where I admit that, not only might I be wrong on that, I probably am. That is to say, I did not make a bold statement calling you prideful. I merely suggested that your absolute certainty on the matter, given how odd things are behaving compared to any previous situations with this mod, no mod, or mix of mods, made the possibility worth considering. So directly saying "You accuse me of pride? That's rather insulting." seems unnecessarily hostile, as I accused you of nothing. If I did not express that clearly, then I apologize for the insufficient attention to my communication.

As for the topic. If you think its fine, then for the purposes of the mod, it must be fine. However like I said, that at no point with this mod in the passed, FAR or stock, has this behavior appeared, and it seems completely counter intuitive to me. While things might have just been unrealistic all along, the fact that I now have no clue what to expect from reentry, not only with the heating elements (which I LOOOOVE btw, very very nice job on that), but also from what will behave how, make the experience to different from what I'm use to, and want. As such I'll merely have to wait around and see if things change, or dabble with less desirable fixes (like the CFG file I'm using to increase reentry difficulty atm).

Thanks for your time, and the clarity with which you addressed my problem

[Kussris]

If you increase convection factor that will serve to increase the rate of heating. I like to adjust radiation factor to match; it makes spaceplanes more viable. You can also adjust aero heating production, which I was doing for awhile but it makes things too hot in subsonic. You can also go into the stock difficulty settings and increase reentry heat there by up to 120% and that does affect Deadly Reentry. (mach only)

Thanks for the answer! I get the re-entrey effects during launch (red flames). Is there a way to adjust Deadly Reentry so that the flames are only on reentry?

[Starwaster]

Thanks for the answer! I get the re-entrey effects during launch (red flames). Is there a way to adjust Deadly Reentry so that the flames are only on reentry?

No, they're based on airspeed and atmospheric density modified by aeroFXExponent.

Actually, these three settings control that:

    @PHYSICSGLOBALS
    {
        @aeroFXStartThermalFX = 2
        @aeroFXFullThermalFX = 3.5
        @aeroFXExponent = 3
    }

where the first two are the mach range where flames start and are at their strongest (so starting at mach 2 and ending at mach 3) and also modified by density. (there's a setting for that too but I'm not sure if it's exposed to config file modification)

They're probably your best bet; you could increase the range in which flames occur based on what effect you want to achieve.

You could also ask NathanKell, he can probably tell you about the other settings and whether or not you could use them in a config patch. (that's what that code section above does. Put that in any file ending in .cfg and modify the values to taste and then save.)

Edited June 5, 2015 by Starwaster

[Gryphon]

Thanks for the answer! I get the re-entrey effects during launch (red flames). Is there a way to adjust Deadly Reentry so that the flames are only on reentry?

No, they're based on airspeed and atmospheric density modified by aeroFXExponent.

Or, you could just slow down.

I should add that if you are going fast enough to see heating effects during launch, you are probably losing a fair amount of energy to drag. Keeping your speed lower until the atmosphere thins out should save some fuel.

Edited June 5, 2015 by Gryphon

[Starwaster]

Or, you could just slow down.

I should add that if you are going fast enough to see heating effects during launch, you are probably losing a fair amount of energy to drag. Keeping your speed lower until the atmosphere thins out should save some fuel.

Except that visually the effect does need toning down. It's too intense on ascent. I might need to do something in DRE.

[NathanKell]

It's because DRE lowers the density exponent--that's used both for convection and for aero FX. In 1.0.2 there's not a lot that can be done other than lowering the aeroFX exponent (try 2.8 maybe?).

The aeroFX start and full don't control strength btw, they just control the transition from white to orange.

[FreeThinker]

Could Deadly reentry please leave Interstellar Engines alone, it's terrorizing my players!

[Gryphon]

Could Deadly reentry please leave Interstellar Engines alone, it's terrorizing my players!

I'm not terribly familiar with KSP Interstellar Extended, but since DRE overhauls the heating system, I presume that would affect any of your parts that generate heat.

You can see the same issue with FAR - since it replaces the stock aerodynamics system, it affects the aerodynamics of every mod part, which has caused some "unfortunate interactions."

I just took a quick look at the DRE config files, and I don't see one there for KSP Interstellar Extended. So, it would seem that the problem is not DRE doing something to your Interstellar Engines, it's that DRE is "leaving your mod alone," and you are having difficulty making your mod compatible with DRE. That is understandable, since DRE is certainly more complex than the stock heat system.

Your post seemed (to me) like you were accusing DRE of terrorizing players who use both DRE and your mod. That would be quite rude, so I'm assuming that is not the message you intended to send. I'd prefer to believe that you are merely requesting the developer of DRE to work with you to make the two mods compatible. Is that what you are actually trying to say?