[0.20] Deadly Reentry 2.3 - reentry heat, plus thermal and g-force damage to parts

[ialdabaoth]

Thanks for that!

By the looks of it it appears to have understood the mod because all the parts now have a temperature associated with them, however i'm not sure if they are actually overheating the way they are supposed to. As you can see from the image below, with that speed and that altitude, i thought there would be no way anything would survive. V1.3 would cause things to ignite long before then. Unless the new version is supposed to work like this?

1.3 was way, way more harsh than it should be. In 1.3 and earlier, the effective temperature of the shockwave was infinite - so you could explode at almost any speed if you didn't decelerate fast enough.

In 2.0, the temperature is capped by the velocity, so as long as you are going under 2 km/s you'll get a lot of pretty lights but nothing will explode.

here's how the logic is working in 2.0:

A) all parts have their maxTemp halved, so your capsule will have a maxTemp of around 1700

According to the oracle, the temperature of the shockwave in Kelvins is approximately equal to the speed in m/s. Since the game uses Celsius, your shockwave temp is somewhere around your velocity - 275.

C) The temperature at which any object begins emitting visible black body radiation (aka "glowing red") is 525 C. Therefore, at 800 m/s (525C ~= 800K) your contrail begins glowing.

D) Each part that is not shielded by another part gains heat from the shockwave until it reaches thermal equilibrium with it. The rate of heat increase depends on the difference between the temperatures and the density of the air - so you'll gain heat about 2.7 times as fast at 30 km altitude as you would at 35km altitude. This is fiddly - I might need to adjust the density exponent here.

E) if your part has a heat shield, that shield has three components: an angle, a reflective factor, and an ablative factor. The reflective factor ranges from 0 to 100%; it's the amount of heat increase that's flat-out ignored if you're coming in at the correct angle, no matter what. The ablative factor represents how much ablative resource gets blasted off your ship as a function of temperature, and how much temperature gets wicked away per chunk of tile that gets melted off.

Edited May 28, 2013 by ialdabaoth

[Killerblonde]

In RC1, I launched straight up, Apo at about 450km, fell straight down a +2km/s with mark1 pod into Kerbin's atmosphere, at about 30km started getting serious reentry, although the heatshield held up fine and only lost about 80 ablation points or so. I'm trying RC2 now.

Edit: Same thing with RC2. I don't think that coming straight down pulling 15+ g's on reentry should be survivable - the heat shield would likely disintegrate under these conditions. I recommend nerfing it a bit - otherwise, successful reentry would be far too easy.

Edit 2: Never mind - steeper reentry angle is more G's, less heat. I understand now. In that case, possibly have some kind of G limit on the heat shield for the sake of overall realism? Maybe the higher G's it receives, the faster the heat shield ablates or something.

Edited May 28, 2013 by Killerblonde

[Ph34rb0t]

Is the Module Manager contained within the DealyReentry.dll?

If not, the manager's .dll is not in the download.

In any case, thanks for this. I can finally retire PerkledHostage's reentry mod.

[Stochasty]

Actually, it occurs to me that maybe the behavior I'm experiencing is normal (and I was just confused by the bass-ackwards way heating in 1.3 worked). Steeper angles should have less heating, due to shorter duration exposure to the high temperatures. This is what I'm seeing: Ap: 100km, Pe: 35km and I lose about half of my shielding. Ap: 100km, Pe:-450km and I lose less than a quarter.

The unphysical part of this is that on the nose-dive reentry, my craft isn't breaking up due to g-stress the way it should.

EDIT:

C) The temperature at which any object begins emitting black body radiation is 525 C. Therefore, at 800 m/s (525C ~= 800K) your contrail begins glowing.

This isn't true. Bodies at any temperature above absolute zero emit blackbody radiation. 525 C might be the temperature at which that radiation begins to become visible, but that's not the same thing as not emitting radiation at all. There will be radiative heat transfer even below this point (although it will be lower), so if you spend enough time at those speeds you can still cook.

Edited May 28, 2013 by Stochasty

[ialdabaoth]

This isn't true. Bodies at any temperature above absolute zero emit blackbody radiation. 525 C might be the temperature at which that radiation begins to become visible, but that's not the same thing as not emitting radiation at all.

That's correct, I just forgot the word 'visible'. At any speed over 300 m/s, you will experience some heating, but the contrail starts glowing visibly at 800 m/s.

[Stochasty]

That's correct, I just forgot the word 'visible'. At any speed over 300 m/s, you will experience some heating, but the contrail starts glowing visibly at 800 m/s.

I suspected this is what you meant; just wanted to make sure. The 'P' in PhD stands for pedantic, after all.

[ialdabaoth]

Edit 2: Never mind - steeper reentry angle is more G's, less heat. I understand now. In that case, possibly have some kind of G limit on the heat shield for the sake of overall realism? Maybe the higher G's it receives, the faster the heat shield ablates or something.

Note that this mod's primary concern is heat, not G-forces. Worrying about what G-forces are survivable would be a nightmare, because of other mods doing the same thing (most notable FAR). Although at some point, DeadlyReentry and FerramAerospace should probably be merged somehow, at which point G-force considerations would be easy.

[asmi]

Actually, it occurs to me that maybe the behavior I'm experiencing is normal (and I was just confused by the bass-ackwards way heating in 1.3 worked). Steeper angles should have less heating, due to shorter duration exposure to the high temperatures. This is what I'm seeing: Ap: 100km, Pe: 35km and I lose about half of my shielding. Ap: 100km, Pe:-450km and I lose less than a quarter.

Actually that part doesn't make physical sence since atmosphere is much less dense up high and so should cause less heating although for prolonged time.

[ialdabaoth]

Actually that part doesn't make physical sence since atmosphere is much less dense up high and so should cause less heating although for prolonged time.

actually, here's what happens:

At a shallow angle, you tear through the atmosphere at speeds of several km/s. Final temperature is dependent entirely on speed, although how quickly you reach that temperature is dependent on density.

At a steep angle, you slow down VERY quickly, so while you're lower in the atmosphere and hence heating up faster, the temperature you're heating up TO is lower, because you've just experienced 18+ G's of acceleration.

[Stochasty]

Actually that part doesn't make physical sence since atmosphere is much less dense up high and so should cause less heating although for prolonged time.

There is a trade off. If you stay high enough, you are correct that the low density wins out and you'll experience less heating; also, you won't slow down very much. This is okay if you are aerobraking and will be returning to orbit. Not so useful for reentry.

Go lower, and the density increases to the point that you'll equilibrate before you slow down. This is bad; it means you fry and die. The solution, then, is to go even lower still, so that you slow down before you equilibrate.

[nhnifong]

I am unable to get it working. I unzipped the contents of the zip file into a folder inside GameData called DeadlyReentry.

Is there some indicator that it's installed, like a UI box?

[rkman]

Test report:

The 2 man lander can survived a rather steep reentry from 250km.

Temp got up to about 800c.

[asmi]

With v1.3 the only survivable reentry I was able to come up with that would be more or less repetitive (meaning I've done it on first try ) was to drop Pe to ~38-40 kms, then as you "bounce off" atmosphere heatshield cools down and also bleeds off enough speed so it was safe to drop into thicker air without burning out. If currently all it gets to reentry is to drop vertically down it kinda kills the fun... Maybe you can speak to Ferram as to include high-G desintegration? But again in real life crew would be dead long before any structural damage is done to the capsule...

[airminer]

I am unable to get it working. I unzipped the contents of the zip file into a folder inside GameData called DeadlyReentry.

Is there some indicator that it's installed, like a UI box?

You can check what plugins are loaded in the debug menu, under the tab named "assemblies".

[Moon Goddess]

Note that this mod's primary concern is heat, not G-forces. Worrying about what G-forces are survivable would be a nightmare, because of other mods doing the same thing (most notable FAR). Although at some point, DeadlyReentry and FerramAerospace should probably be merged somehow, at which point G-force considerations would be easy.

Please don't completely combine DeadlyReEntry and FAR, I like DeadlyReEntry, but find FAR just way way too complex for me to use.

[rhoark]

FAR is probably complex internally, but as far as using, it goes like this:

1. Install

2. Enjoy more realistic aerodynamics

3. Keep moving the stupid windows out of the way because you don't really need to adjust anything on them.

[gabmaia]

Any good heatshield packs out there?

[Moon Goddess]

3. Keep moving the stupid windows out of the way because you don't really need to adjust anything on them.

Well they scared me enough I uninstalled the mod, I tried to read through all that stuff and yeah...

All I could figure out is I had a rocket that flew before, and didn't after, and got this window on my screen that I don't understand... time to get rid off.

Maybe I'll give it a new try.

[Killerblonde]

That's the same problem I had with it... annoying windows everywhere. Is there a way to disable them? It would seem to me like there would have to be....

EDIT: Also, to my knowledge, FAR only causes G forcing damage on larger vessels. A single command pod can still hurtle towards the atmosphere and take 44 G's straight down, and stands a better chance of surviving than going for a more realistic reentry. I don't want to be pushy or anything, and I know there are more important things to take care of first, but it seems like a rather large flaw in a realism mod to be able to make your reentry angle arbitrarily steep in order to be sure you survive it.

Edited May 28, 2013 by Killerblonde

[NannerManCan]

Where's ds store supposed to go?

[Stochasty]

Okay, after some more testing, there's some very definite issues with engine heating - at least in conjunction with your ModularFuelTanks mod. LV-Ns overheat at 50% thrust. Aerospikes running LOX+LH2 at about 60%, running LOX+LiquidFuel at less than 50%. LV-T45 overheats on LOX+LH2 at 100% but is stable at 90%. Overheats more quickly on LOX+LiquidFuel, but I'm not sure the exact percentage. Couldn't test the LV-T30, since it's not configurable.

Seems to be that the reduction in heat tolerance from Deadly Reentry doesn't play well with the changes to engine heat generation from ModularFuelTanks.

Edit: Potentially hacky solution: rather than reducing maxTemp values for all parts by 50%, pretend that maxTemp values are given in Fahrenheit, not Celsius. (Actually, given their stock values, do we know for certain the temps are Celsius?)

Edited May 28, 2013 by Stochasty

[Nobody_1707]

Where's ds store supposed to go?

That stores data for the Mac desktop. It shouldn't be there at all, but it's a bit difficult sometimes to keep them out of archives.

[NannerManCan]

Well it seems like the heat has been toned down. From a 100km orbit I came down at 2182.5m/s from 70KM up then 2252m/s at 35KM. Nothing exploded just some flames. I had to go to about 500km above kerbin then I fired my rocket straight down until I was going like 2800m/s the ship started exploding but my capsule and the fuel tank, asas, and engine below it were still fine. Also are we going to get some heat shield parts?

Edited May 28, 2013 by NannerManCan

[Lexif]

Is it just me or is the download down?

[nhnifong]

Any good heatshield packs out there?

No but fairing factory can be used in a pinch.