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

Starwaster

By Starwaster
in KSP1 Mod Releases

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Starwaster

Starwaster

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They were genetically engineered to like being experimented on!

Huh, I thought they were genetically engineered to like being blown up.

On another thread, there's a very tiny tweak to stock that seems to make 120% feel nice and deadly… except for the thermometer memory leak, I'm really happy with the (slightly tweaked) stock thermal mechanics, although I'll probably try out DRE to compare.

I've been experimenting with a spreadsheet and inputting various values for the heat shield and one thing that I'm getting some good ablation rates from is from treating lossExp as a baseline velocity, inverted*

If I change it from -9000 to -5000 I get some good rates. Not enough to threaten total burn through but about 2/3. I figure a Minmus return would probably blow a big chunk of that shield away

Edit: * Nope. I've just been told it had nothing to do with that. Well even so it seemed to have worked. (at least in conjunction with my skin heating system)

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Starwaster

Starwaster

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i tried the reentry heat balance, and it doesn't seem to work for me. I came in at 3 km/s without a heatshield and it was perfectly fine. FAR might be messing with it. Whatever the reason is, I'm not going to start playing until this updates. Nothing beats DRE!

What reentry heat balance is that?

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Starwaster

Starwaster

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The one Astrospeak linked to.

yeah that by itself is at best a stopgap. I played around with config only fixes when I first got to test the system when it was in Experimentals. The problem is that it's all or nothing and doesn't address the real issues. Also playing with shield conductivity is no good. They're supposed to be insulated just like real shields would have between them and what they're protecting.

Anyway it won't be too much longer until DRE is ready for release. Sadly I just lost a few hours of coding and testing due to power outage.

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LORDPrometheus

LORDPrometheus

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yeah that by itself is at best a stopgap. I played around with config only fixes when I first got to test the system when it was in Experimentals. The problem is that it's all or nothing and doesn't address the real issues. Also playing with shield conductivity is no good. They're supposed to be insulated just like real shields would have between them and what they're protecting.

Anyway it won't be too much longer until DRE is ready for release. Sadly I just lost a few hours of coding and testing due to power outage.

hey we understand

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Gaugeforever

Gaugeforever

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On another thread, there's a very tiny tweak to stock that seems to make 120% feel nice and deadly… except for the thermometer memory leak, I'm really happy with the (slightly tweaked) stock thermal mechanics, although I'll probably try out DRE to compare.

my parachutes burn up with his .cfg

I tested it by bringing a pod back from orbit with two radial chutes in symmetry and one top chute. Tossed a heat shield on it.

Didn't matter if I came in SUPER shallow and slow (took forever), or deep. Burned up both times. I even tried it on 100% Heat, still had the same issue. Removed it for now. Perhaps I'm doing something wrong? I would think orbital speed would not cause enough heat to destroy all the parachutes if you keep your shield pointed at retro.

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Starwaster

Starwaster

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Oh no! I hope it isn't difficult to re-do. I would help if I could, but I can't.

Oh, no I don't mean any work was lost, just time in which I could have been coding was instead spent staring at pitch blackness.

my parachutes burn up with his .cfg

I tested it by bringing a pod back from orbit with two radial chutes in symmetry and one top chute. Tossed a heat shield on it.

Didn't matter if I came in SUPER shallow and slow (took forever), or deep. Burned up both times. I even tried it on 100% Heat, still had the same issue. Removed it for now. Perhaps I'm doing something wrong? I would think orbital speed would not cause enough heat to destroy all the parachutes if you keep your shield pointed at retro.

Were they deployed and then burnt up or you mean that just sitting there they were incinerating before you even had a chance to deploy?

(because both stock and Real Chutes will be shredded or incinerated if you deploy while going too fast. Just like older versions of DRE used to do. Which means that from 7.0 going forward, DRE will no longer destroy chutes that you deploy too quickly. Because we don't have to anymore <VEG>)

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Gaugeforever

Gaugeforever

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Were they deployed and then burnt up or you mean that just sitting there they were incinerating before you even had a chance to deploy?

(because both stock and Real Chutes will be shredded or incinerated if you deploy while going too fast. Just like older versions of DRE used to do. Which means that from 7.0 going forward, DRE will no longer destroy chutes that you deploy too quickly. Because we don't have to anymore <VEG>)

Before deploying. I have 200 hours with FAR and DR :P They just burn up. Doesn't really make sense to me honestly. I could MAYBE see the radials getting too hot, but the top mounted chute... how does that burn up without the pod burning up.

Not sure why other people aren't having issues. It could be because I'm using ferram aerospace. I didn't consider that.

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pacbard

pacbard

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Before deploying. I have 200 hours with FAR and DR :P They just burn up. Doesn't really make sense to me honestly. I could MAYBE see the radials getting too hot, but the top mounted chute... how does that burn up without the pod burning up.

Not sure why other people aren't having issues. It could be because I'm using ferram aerospace. I didn't consider that.

As Starwaster said:

yeah that by itself is at best a stopgap. I played around with config only fixes when I first got to test the system when it was in Experimentals. The problem is that it's all or nothing and doesn't address the real issues. Also playing with shield conductivity is no good. They're supposed to be insulated just like real shields would have between them and what they're protecting.

Anyway it won't be too much longer until DRE is ready for release. Sadly I just lost a few hours of coding and testing due to power outage.

changing the head conductivity of the heat shield is not a fix for the heating problem. The heat shield is designed to insulate the rest of the ship from the ball of plasma created during reentry. If you change conductivity, the rest of the ship heats up as well during reentry, creating the issue that you are describing. In your case, FAR might change the thermal shock wave shape just enough so that your parachutes don't heat up as much.

The issue will go away once Deadly Reentry updates anyways.

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Starwaster

Starwaster

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Before deploying. I have 200 hours with FAR and DR :P They just burn up. Doesn't really make sense to me honestly. I could MAYBE see the radials getting too hot, but the top mounted chute... how does that burn up without the pod burning up.

Not sure why other people aren't having issues. It could be because I'm using ferram aerospace. I didn't consider that.

Press alt-F12 and then click Physics, then Thermal.

Then enable 'Display Thermal Data in Action Menus'. Right click the parachute part and it will tell you exactly where the heat is coming from. If it seems like the bulk of it is coming from Conductive then it's probably as Gaugeforever says and too much heat is being conducted through the ship through the shield. The chute parts are smaller and generally have lower thermal mass. If on the other hand it's convective heat then it's not being shielded. Maybe check with ferram and see if that's intended behavior from FAR.

But it's probably not going to be that much of an issue when DRE comes out. I did run DRE alongside FAR to make sure that Flight Integrator interaction was working properly and to see how heating was working with FAR in general and I didn't have an issue with chutes exploding, so I think it'll be ok.

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damerell

damerell

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In preparation for 1.0.2 DRE; in 0.90 I developed an approach where I'd mount a double RealChute on vehicles for re-entry, and make one chute a kevlar drogue, deployed immediately on hitting atmosphere. As a rule of thumb, I'd make the area of that chute (in m^2) 4 times the vessel mass (in tonnes) for Kerbin re-entry. This worked beautifully; by the time I reached the sort of altitude where chutes would burn off, I had already decelerated enough that the drogue stayed intact. In particular, this let me land long thin vehicles which otherwise wouldn't bleed off enough speed in a naive stern-first re-entry.


  • However, as far as I know, no-one actually does this in reality. Is there a reason why it shouldn't work? If there is, I'll stop doing it.
  • I still don't know why the forum eats all paragraphs when I post, giving me a wall of text. Wah.

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Starwaster

Starwaster

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In preparation for 1.0.2 DRE; in 0.90 I developed an approach where I'd mount a double RealChute on vehicles for re-entry, and make one chute a kevlar drogue, deployed immediately on hitting atmosphere. As a rule of thumb, I'd make the area of that chute (in m^2) 4 times the vessel mass (in tonnes) for Kerbin re-entry. This worked beautifully; by the time I reached the sort of altitude where chutes would burn off, I had already decelerated enough that the drogue stayed intact. In particular, this let me land long thin vehicles which otherwise wouldn't bleed off enough speed in a naive stern-first re-entry.

  • However, as far as I know, no-one actually does this in reality. Is there a reason why it shouldn't work? If there is, I'll stop doing it.
  • I still don't know why the forum eats all paragraphs when I post, giving me a wall of text. Wah.

I have no idea if that will still work. Deadly Reentry will no longer inflict damage on chutes. At least, not on Real Chutes because SC has implemented chute damage himself. I think stock chutes also have deployment limitations now too but I might have imagined that. (in which case, I'll reimpliment damage for stock chutes. I have to check that out)

so in short, try it out first but make sure you have backup chute or your Kerbals may DIE.

And then I'll jeer at you mockingly while posting in Comic Sans.

So, um, how is it looking, Starwaster?

It's looking good. I finished some preliminary testing of spaceplanes but not as much as I would have liked, but it will have to do because I don't do space planes very well, so you guys will get to tell me if they burn up too much or something.

I'm finalizing some other things and going over configurations and Deadly Reentry 7.0 should be up sometime in the next day or two.

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Svm420

Svm420

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I'm finalizing some other things and going over configurations and Deadly Reentry 7.0 should be up sometime in the next day or two.

Hopefully your day or 2 is shorter than ferrams day or two ;)

Kidding I know it will be ready when it's actually ready. :)

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futrtrubl

futrtrubl

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Right. But what I mean is, _should_ it work? If there's some reason it shouldn't, I'll stop doing it.

It's not done in real life because unfortunately your assumption that there is somewhere you can decelerate at high velocities without heating is incorrect. If you are decelerating then your kinetic energy is being reduced. That energy has to go somewhere and that somewhere is in heating the air around the chute which heats the chute itself. Remember that the shock temperature in Kelvin is roughly equal to the speed of the craft and parachutes have a large area for thermal transfer and very low thermal mass so they heat very quickly.

Then there is the fragility, take a look at the supersonic chute on the LDSD test.

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Starwaster

Starwaster

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And, I *think* that stupid_chris is doing checks for both heating and stress damage on the canopy.

Regarding heating, here's what governs which way heat flows: From hotter temperature to cooler temperature. How MUCH heat depends on the densities of the respective. At higher altitudes, sure the air is thin but so is the canopy. And the larger it is the more heat it can collect. So it can heat up fairly quickly. My guess is that it will fail from melting (or decomposition; Kevlar doesn't melt. It just weakens at higher temperatures and then comes apart)

And his code isn't even dependent on Deadly Reentry anyway. So you can definitely give it a try right now.

Actually I'm going to try it right now myself and see what happens. My guess is that it's going to be pretty ugly.

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