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

[Wanderfound]

The Mk2 docking ports will also fail to shield things from drag under FAR (to paraphrase Ferram, "if you want stuff shielded, use a damn cargo bay; that's what they're for").

So, yeah: if you want to get your assorted widgets through reentry safely, use a small cargo bay as a service compartment. Good for batteries, SAS, science instruments, etc. And stick the landing gear on the outside as designed; they'll come through reentry just fine.

[NathanKell]

Well, they'll come through *Kerbin* reentry just fine; that question originated on the RO thread, and that's an important bit of context. Though I do recall it possible to fly a *very* careful lifting reentry in a spaceplane in RSS even without shielding buffs.

[Eunito]

The Mk2 docking ports will also fail to shield things from drag under FAR (to paraphrase Ferram, "if you want stuff shielded, use a damn cargo bay; that's what they're for").

So, yeah: if you want to get your assorted widgets through reentry safely, use a small cargo bay as a service compartment. Good for batteries, SAS, science instruments, etc. And stick the landing gear on the outside as designed; they'll come through reentry just fine.

But what about the side shutes? Inside a special bay? :S

They keep exploding on reentry... I know I'm a newb... I don't want to put them on top because I use the top for dockings... :/

[Wanderfound]

But what about the side shutes? Inside a special bay? :S

They keep exploding on reentry... I know I'm a newb... I don't want to put them on top because I use the top for dockings... :/

Well, if it's a spaceplane, you don't need chutes. Land it like it's supposed to.

But if you must have chutes, then yes, they work just fine when deployed from a bay:

[Eunito]

I was taking of a normal landing capsule with 1/2 or 3 chutes on the side.

No bottom shield projects them in reentry...

[ArcFurnace]

In the past, I was usually able to attach radial chutes to the sides of the 1.25m capsule without them burning up, so long as I made sure they were near the top where the capsule narrows so they're "inside" the shielding cylinder provided by the heat shield on the bottom. Alternately, for really big radial stuff sometimes you can use an oversized bottom-shield (e.g. the 4m heat shield). Is something similar not working for you? Make sure you've got your heat shield pointed prograde, of course.

[Starman4308]

I was taking of a normal landing capsule with 1/2 or 3 chutes on the side.

No bottom shield projects them in reentry...

Leave them up at the top, safely behind the cylinder of protection offered by the heatshield.

Make sure you have a heat shield.

Also make sure you are not deploying your parachutes into superheated reentry plasma. Nylon does not like 2000 degree reentry plasma. Wait until you're around 200-250 m/s before popping chutes: Mach 1 is about 330 m/s, and supersonic velocities will eat your chutes.

[Starwaster]

Leave them up at the top, safely behind the cylinder of protection offered by the heatshield.

Make sure you have a heat shield.

Also make sure you are not deploying your parachutes into superheated reentry plasma. Nylon does not like 2000 degree reentry plasma. Wait until you're around 200-250 m/s before popping chutes: Mach 1 is about 330 m/s, and supersonic velocities will eat your chutes.

Deploy not your parachutes into the supersonic slipstream for your Kerbals are crunchy and tasty with ketchup.

[Wanderfound]

I was taking of a normal landing capsule with 1/2 or 3 chutes on the side.

No bottom shield projects them in reentry...

As the others have said: hide 'em in the heatshield shadow. And make sure that you keep the capsule pointed exactly retrograde (it should do this itself with SAS off due to aerodynamic forces, unless you've added some asymmetric drag to it), so the plasma doesn't sneak around the edges.

[Starman4308]

Deploy not your parachutes into the supersonic slipstream for your Kerbals are crunchy and tasty with ketchup.

At some point, my morbid curiosity will have me trawling through the DRE and RealChute threads to find out how many people have complained about parachutes burning up. Bonus points for posting screenshots with visible reentry effects.

Better not make it a drinking game, though.

As the others have said: hide 'em in the heatshield shadow. And make sure that you keep the capsule pointed exactly retrograde (it should do this itself with SAS off due to aerodynamic forces, unless you've added some asymmetric drag to it), so the plasma doesn't sneak around the edges.

Pointing exactly retrograde isn't always the best choice, though. If you've got FAR, you can give yourself a few degrees of pitch above retrograde for a lifting effect, keeping you in high atmosphere longer, bleeding off speed in the Goldilocks drag zone. It does increase risk of exposing a part to reentry burn: if you have asymmetric parts (particularly the Pegasus I ladders*), you will often want to rotate the capsule so that the bulky parts are on the bottom, since they will be more shielded from reentry burn that way.

*RCS thrusters are also frequent offenders, but since they're generally radially symmetric, there's no real solution to that, other than making sure your heatshield gives you enough of a shadow to hide the RCS, and not having too extreme of pitch. Also, what I call the "Goldilocks drag zone" is that region of atmosphere which will give you substantial drag in a short amount of time, without immediately stripping your heatshield off. Spend too long in really high atmosphere, and you lose speed too slowly: you will start heading for low atmosphere without shedding much horizontal velocity. Go in too steep, and you go straight to lower atmosphere, do not pass Go, do not collect $200.

Edited November 12, 2014 by Starman4308

[Starwaster]

At some point, my morbid curiosity will have me trawling through the DRE and RealChute threads to find out how many people have complained about parachutes burning up. Bonus points for posting screenshots with visible reentry effects.

Better not make it a drinking game, though.

Drink a shot when:

• Player complains DRE is too hard.
  
• Player complains DRE is too easy.
  
• Player complains that parachutes keep burning up / won't deploy / destroyed.
  
• Rocket burns up during ascent.
  
• Small bits burn up during ascent.
  
• Kerbals catching fire.
  
• Kerbals dying from g-forces.
  
• Player swears that only shallow reentries are the best.
  
• Player swears that only the steepest reentries are the best.
  
• Starwaster posts picture of Cleopatra the Feral Cat.
  

[JT2227]

Thanks for the help! And btw the parachute is to slow the shuttle on the runway, the brakes spin it out of control.

[Drew Kerman]

Drink a shot when:

Are you trying to kill someone??

[Starwaster]

Ok, beta release time is here:

Deadly Reentry version 6.3.0 beta

Version 6.3.0 is mostly complete though it has some new experimental features that might break things or just not work as intended. Easy setting SHOULD be sufficiently easier for those having a tough time but needs hands on by people who might actually want such a thing. Hard might not be hard enough; it uses careful and unusual adjustment of densityExponent, temperatureExponent, heatMultiplier and the new alternate density adjustment. (be really careful altering that setting as it can nerf heating badly if other settings aren't adjusted properly)

Partial changelog is here:

- Chute failure message made more generic

- Added unsafe chute deployment warning messages (do not deploy while warning is displayed)

- Changed stock chute and Real Chute defaults to deploy at (usually) safe altitudes on Kerbin. Change at your own risk!

- Experimental alternate density toggle. (intended for use with Hard setting where temperatures were ramped up greatly. Very WIP)

- Some properties were made non-persistant so that existing heat shields will be properly updated if their part configs were updated.

- Shields now insulate attached parts

- Added version to debug window.

- Reentry awareness

- Added soft heat cap to heat shields. (shield dissipation rate increases tremendously as they approach max temp)

- Implemented difficulty levels (Easy, Normal, Hard) on a per save game basis.

- Difficulty can be changed per save game.

- Debug menu changes apply only to current difficulty level.

- Added toolbar button (icons courtesy of lajoswinkler)

- Revamped node saving / loading to accomodate difficulty system.

- Added LeadBallast resource if RealFuels is not present. (if RF is present, it has its own LeadBallast resource)

- Added LeadBallast resource to the inflatable heatshield. (0 quantity by default. Increase as desired to stabilize the heatshield and prevent flipping)

New Toolbar Menu:

- Easy, Normal and Hard settings (still WIP; settings subject to change and open to player feedback before final release)

- Easy access to Debug Menu

- Legacy Aerodynamics (no per-planet gas constant. Density and heating same for all planets)

- Heatshield temperature damping (as temperature approaches maxTemp, DRE will try to damp further heating)

- Alternate Density (densityExponent will be ignored and density will be reduced for heating calculation: USE CAREFULLY. Intended for creation of hard settings to keep upper atmosphere from being excessively lethal and to reduce launch heating. VERY MUCH A WORK IN PROGRESS)

Edited November 12, 2014 by Starwaster

[NathanKell]

Sounds most intriguing! Will try when I get home.

Question: do you mean to increase dissipation rate (not loss rate)? That means that a heatshield will make you invulnerable, so long as ablative holds out, and ablative loss rate does not increase when dissipation increases, it's independent.

[Starwaster]

Sounds most intriguing! Will try when I get home.

Question: do you mean to increase dissipation rate (not loss rate)? That means that a heatshield will make you invulnerable, so long as ablative holds out, and ablative loss rate does not increase when dissipation increases, it's independent.

Originally, that was in fact my intent. In spite of the increased dissipation, it is still possible in extreme conditions to destroy the shield and I'll probably leave it like that. Even so, it should be pretty hard IRL to destroy a heat shield as long as there's some ablator remaining. It's the same concept that makes it possible to boil water in a paper cup over an open flame. The paper won't go past the boiling point of water as long as water remains. But it didn't quite work as intended so it only damps the temperature rather than acting as hard clamp. It can't currently be configured but it can be turned off.

On, it can be destroyed but it took me hard setting (part of the reason it came into being), FAR and RSS lunar returns

[NathanKell]

Yeah, the problem isn't that it should be easily destroyable, the problem is that dissipation isn't connected to loss rate, so your loss rate will be constant no matter what dissipation you set. If I were you (I'm not though!) I'd add a second loss rate curve (that serves as a multiplier) based on part temperature, and use a constant for dissipation.

[Starwaster]

Yeah, the problem isn't that it should be easily destroyable, the problem is that dissipation isn't connected to loss rate, so your loss rate will be constant no matter what dissipation you set. If I were you (I'm not though!) I'd add a second loss rate curve (that serves as a multiplier) based on part temperature, and use a constant for dissipation.

Yes, I don't know why loss isn't based on part temperature; I assume that predates your involvement as well. Unless perhaps the intent was to simulate skin temperature without raising the entire part's temperature, which makes a certain amount of sense. One might assume that the shield is going to pick up X amount from the shockwave. Involving air density seems a bit strange though because most of the shield's loss would be from pyrolysis. Using air density makes me think erosion, which should really only happen to the charred part of the shield.

I don't agree though that dissipation should be a constant because it's losing heat because some of it was carried away by the shield material that ablated away. It's like the water in the paper cup analogy. Where did the heat go that should have ignited the paper cup? Answer is, it boiled off with the water.

Bottom line is probably that I'll come back and revisit this at some point. Maybe make loss dependent on part temperature outright instead of playing around with yet another curve. If I did that then I would bump the dissipation rate to compensate for letting the shield get so hot. (which is actually ok now because we're setting heatConductivity to 0.01 now for ModuleHeatShield. It can get as hot as it wants and not transmit any of that to other parts)

BTW, I did reduce ridiculousMaxTemp, but not nearly as much as I was talking about doing before. Given your experience with high TWR rockets in full sized RSS, I'm interested in how that turns out for you. If you set difficulty to Hard, it should actually reduce the lower atmosphere heating enough to be survivable. (EDIT: Oops, Alternate Density calc isn't being saved by difficulty setting so it may be turned off. That configuration was meant to have it enabled)

To All: One thing not in the changelog that I think I mentioned I was doing before: Stock chutes (not radial) and Real Chute cone parts have weak built-in heat shielding as long as no chutes were deployed. (as soon as the cap comes off, they are exposed)

Also interested to see if anyone noticed what else I did ...

Edited November 12, 2014 by Starwaster

[NathanKell]

You might be interested in the shield rewrite I did then. It uses the real formula Goozeman posted many months ago.

Will try when I get home.

[DaMichel]

I have a little issue with DRE. Basically i tried to predict when stuff will burn up based on part.temperature and part.maxTemp. Now i had a look at the code and see

 if (is_engine && damage < 1)
  damageThreshold = part.maxTemp * 0.975f;
else if (is_eva)
{
  damageThreshold = 800 * (1 - damage) * (1 - damage) - CTOK;
  part.maxTemp = 900;
}
else
  damageThreshold = part.maxTemp * 0.85f;

So does this mean that say fuel tanks will burn up when they reach 85% of their parts maximal temperature rating? If so, i think it is a bad idea. It is bad for Kerbal Flight Data because i need to dublicate DRE logic to figure this out and it is bad for userd because they'd probably assume that temperatures below maxTemp are safe. I would rather just write

if (part.temperature > part.maxTemp)
   addDamageUntilDead()

for all parts equally. It seems odd though. Is there something i'm missing?

Edited November 13, 2014 by DaMichel

[Starwaster]

I have a little issue with DRE. Basically i tried to predict when stuff will burn up based on part.temperature and part.maxTemp. Now i had a look at the code and see

 if (is_engine && damage < 1)
  damageThreshold = part.maxTemp * 0.975f;
else if (is_eva)
{
  damageThreshold = 800 * (1 - damage) * (1 - damage) - CTOK;
  part.maxTemp = 900;
}
else
  damageThreshold = part.maxTemp * 0.85f;

So does this mean that say fuel tanks will burn up when they reach 85% of their parts maximal temperature rating? If so, i think it is a bad idea. It is bad for Kerbal Flight Data because i need to dublicate DRE logic to figure this out and it is bad for userd because they'd probably assume that temperatures below maxTemp are safe. I would rather just write

if (part.temperature > part.maxTemp)
   addDamageUntilDead()

for all parts equally. It seems odd though. Is there something i'm missing?

Two things:

1. Deadly Reentry is like The Walking Dead: Nobody is safe.
   
2. Secondly, your code snippet will not be reached more than once, and probably not EVEN once. Stock KSP will destroy the part as soon as it sees that the part's temperature has exceeded maxTemp
   
3. (I lied about there being two things. I do that) The DRE code you cited does not mean the part will burn up when reaching their damage threshold (85% or 97.5%) it means they will start to take damage. They are not immediately destroyed. Taking damage has several deleterious effects such as reduced ability to withstand excessive g-force or in the case of heat shields, they may not protect as well. Destruction is neither immediate nor certain.
   

[Starwaster]

Forgive the double post but I wanted this to be separate from my reply to DaMichel

Update to the Version 6.3.x beta: Deadly Reentry v6.3.1 beta

The single change is that the toggle for the Alternate Density calculation used for calculating heat has been made persistant unique to each difficulty level as with the other settings. (for the most part, leave this setting alone unless you are trying to make things Hard and the level of heat got to be too much. Then you turn that on and it will cut the heat down which will have a lot of benefit in the lower atmosphere when going supersonic during launch)

[DaMichel]

Fair enough. It makes sense now that i understand that the stock game destroys parts which exceed maxTemp. Perhaps for some future update (Nathans Heat project?) it would be worth exploring if it is possible to increase maxTemp right when the flight starts. So the editor would show the original maxTemp but in flight parts would only start to take damage at that point.

W.r.t 3) i say that for me a part that starts to take damage might just as well be instantly destroyed. Of course this would take way the pretty burn effects. Nevertheless you have just a second or so until it explodes. It is sometimes enough time to cut the throttle but not enough time at all for maneuvering.

[Jovus]

W.r.t 3) i say that for me a part that starts to take damage might just as well be instantly destroyed. Of course this would take way the pretty burn effects. Nevertheless you have just a second or so until it explodes. It is sometimes enough time to cut the throttle but not enough time at all for maneuvering.

I would very much disagree. I've ridden through about a minute and a half in some reentries with bits of my plane starting to burn but ultimately staying intact(ish).

[taniwha]

The overheat burning effect is also a nice warning for when your engines are about to blow due to running them too hot, and then cutting the throttle is almost always the right thing to do.