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

[AbeS]

RSS is the Real Solar System mod by Nathan, with that mod installed you really need to be careful with the reentries, and will always need heatshields

[Mounti]

RSS is the Real Solar System mod by Nathan, with that mod installed you really need to be careful with the reentries, and will always need heatshields

I have a question concerning reentering with the Real Solar System Mod. I tried reentering Mars athmosphere with about 5km/s and I tried altitudes from 10km-20km.... none of them are working. I either crash into the ground or exit athmosphere and reenter a second time with the result of crashing into the ground. ... Any ideas?

[BrickedKeyboard]

You're saying that Mar's atmosphere is not enough to stop you? That's true in real life, isn't it? I think the aerobraking they do with space probes has to use a very long path through the atmosphere and they have to use a rocket at the end.

[SZDarkhack]

I have a question concerning reentering with the Real Solar System Mod. I tried reentering Mars athmosphere with about 5km/s and I tried altitudes from 10km-20km.... none of them are working. I either crash into the ground or exit athmosphere and reenter a second time with the result of crashing into the ground. ... Any ideas?

The Martian atmosphere is very thin, so it's not that good for aerobraking, especially for ballistic (i.e. non-winged) vessels. Try doing multiple passes through it. Get a capture with your first pass (any capture, it doesn't matter how high the apoapsis is) and loop around a few times passing through the atmosphere until the orbit eventually comes down.

[Mounti]

You're saying that Mar's atmosphere is not enough to stop you? That's true in real life, isn't it? I think the aerobraking they do with space probes has to use a very long path through the atmosphere and they have to use a rocket at the end.

I'm trying to do a Curiosity style landing. So: Reentry --> parachutes --> powered descent. While opening the chutes Curiosity was down to ~450m/s so I thought something similar would be possible. I thought about trying SZDarkhack's method of "bouncing" and slowing down. But that did not feel right.

[jrandom]

I've been away for a bit (KSP ate my life and I had to take a break after four months). Anyone know if the 6-meter heatshield extra-lift problem with FAR has been solved? That doomed my Eve mission and I haven't had a chance to try out this new version yet.

[Ricardo.b]

I use deadly reentry and FAR and I noticed that some debris make into atmosphere and shielded space crafts enter tooooooooo easy (about 10% of abalbative shield spend).

i wonder what values of deadly reentry debugging configuration can i set to make any debris burn and shielded reentry relative simple

anybody know?

thanks

[Kalista]

I use deadly reentry and FAR and I noticed that some debris make into atmosphere and shielded space crafts enter tooooooooo easy (about 10% of abalbative shield spend).

i wonder what values of deadly reentry debugging configuration can i set to make any debris burn and shielded reentry relative simple

anybody know?

thanks

Change shockwaveExponent in custom.cfg in the DRE folder from 1 to 1.17 if you want reentry to be alot more challenging. I've been running that with far+dre and have had 3 space shuttles nearly burn up on reenty ( as if the things weren't touchy as is to reenter ).

[NathanKell]

BrickedKeyboard, what you have to remember is that Kerbin is about 1/3 the size of our moon, with an orbital velocity of only about a quarter Earth's. So don't be surprised that reentry is mild. That's why I added shockwave multiplier and shockwave exponent, so that even if you aren't willing to play with Earth-sized Kerbin (via the RSS mod), you can still have Earth-level reentry heating.

The issue with planes...are you cruising at about 25km? Do you have a reasonably high angle of attack (~10 degrees)? Then you should be ok. (And if not, you can't really compare to the SR-71). Airplane fuselage parts _do_ have heat shielding, though like the SR-71 and X-15 it's non-ablative. You really shouldn't be doing badly until say 1400m/s unless you have some parts with really low max temperatures; the shockwave temperature (a funny fact) is your velocity's magnitude in Kelvin, so even at 1400m/s the ambient [from a non-detached shockwave] is only about 1100C. Note I _do_ plan to model shockwaves (and low ballistic coefficients causing detached shockwaves), though not for some time...

jrandom: ferram just fixed capsule lift, and that probably also fixed heatshield issues; I've been away myself for a few days and haven't tried yet though.

[nullreference]

I have noticed a slight performance decrease with Deadly Reentry and I have taken a look at the source code

Is it possible to change the deltaTime value to make less calculations being done (ex: 1 temperature and G-Force calculation per 5 deltaTime) as this would have a lesser performance impact and would also have negligible effect on the gameplay

[Frederf]

With FAR a smooth "bullet" type craft with heat shield on the bottom has 10x Cd facing pointy end first instead of heat shield first. It's because that aero things that the wind is hitting the top of the shield but even then it should be 1:1.

[TechnicalK3rbal]

Does the direction of the heat shield on the cfg file ,ake a difference?

[NathanKell]

Frederf, I'm sorry, but I don't really understand what you're saying. Can you try again?

nullreference: I'm rewriting how DRE does all that; we'll see if that helps.

TechnicalK3rbal: Yes. It only protects when the craft is travelling in that direction (or from all sides if direction is 0,0,0). So a heatshield with direction 0, -1, 0 will only protect when the craft is traveling retrograde.

[Lucius]

Nathan - when adding ablative shielding to parts, is it possible to make it non-directional? Trying to re-do the vostok

[Mein_Gott]

What custom settings shall I use to have strictly visual effects only? I like the idea of atmospheric phenomena depending on my velocity, but not entirely need my craft to overheat

[m4ti140]

Maybe set multiplier to sth ridiculously low?

[NathanKell]

Lucius: If you set all vector components to 0 in the direction vector, it counts as omnidirectional.

Mein_Gott: Set shockwave multiplier to 0, set G limit to 999 or something, and set crewG min to 999 or something. That should do it.

[kong]

my reentry has no fire it just turnig red

[Sokar408]

I was wondering. How does DeadlyReentry do its thing with parts? Will all parts be effected, or will some uncompatible modded parts be uneffected?

[rottielover]

Enhancement request: Radially attachable, inflatable heat shields with decoupler.

For reference material see the Movie: "2010 the year we make contact".

Basically these would be used for aerobraking big ships, who's designs don't allow for hiding everything behind the shields that are currently availible.

[drtedastro]

"Balute" is the term for those.

[metaphor]

Is the shockwave parameter meant to simulate radiative flux?

It might be a little off then since radiative flux is proportional to the 4th power of speed, not exponential. So maybe that's why it underestimates entry from LEO and overestimates entry from Moon. There's also conductive heat flux which is proportional to the 2nd power of speed. I'm not sure how Deadly Reentry calculates temperature.

[Agarax]

Good going keeping this mod alive! I have three suggestions for heat shields:

1) Have the inflatable heat shield have a 'deflate' option.

2) Have a clam-shell like heat shield that can be placed below engines so you can reenter pointing retrograde, open them up, and then burn your engines without having to jettison anything. The perfect part for SSTOs/reusables.

3) Have an actively cooled heat shield that requires a serious amount of electricity and maybe the heat radiators from Interstellar Mod. Again good for SSTOs/reusables.

Thanks!

[FlowerChild]

Nathan, I've been running into some very strange results where ablation seems to occur at a much greater rate when a vessel is low in the atmosphere after it is actually out of any danger from reentry. With one particular set of parameters I'm working on in tweaking a part, this is generating very strange results where no matter how strong I make the heat shield, it winds up burning up on reentry anyways.

So, I've got to ask, is it intended that heat shields be far less effective in the upper atmosphere at high speeds than in the lower at low speeds?

Looking over the code, the parts that confuse me are the combination of the following:

		public static float TemperatureDelta(double density, float temp1, float temp2)
		{
 			if (temp1 < temp2 || density == 0 || temp1 < 0)
 				return 0;
			 return (float) ( Math.Pow (Math.Abs(temp1 - temp2), temperatureExponent) 
 						   * Math.Pow (density, densityExponent)
						   * heatMultiplier * TimeWarp.fixedDeltaTime);
 		}

Now, this temperature delta determines the rate at which parts gain heat, with the max temperature being capped at the "shockwave" value which is just the velocity - 275. The rate at which parts can thus gain heat is modified above by atmospheric pressure, but the max value never is, so parts can get just as hot in the upper atmosphere as in the lower.

Now, the other part I've been looking at is this in AdjustedHeat():

 					float ablation = (float) (dot 
					                           * loss.Evaluate((float) Math.Pow (shockwave, ReentryPhysics.temperatureExponent)) 
 					                          * Math.Pow (vessel.atmDensity, ReentryPhysics.densityExponent) 
 					                          * TimeWarp.fixedDeltaTime);

Here, the atmospheric density is applied as a straight multiplier to the rate of loss based on the shockwave value (i.e. the velocity - 275) to determine the rate of ablation, as opposed to the delta between the current part temperature and the shockwave value as it is above. This means you can be traveling at high speed in the upper atmosphere, generating a ton of heat, and still be ablating less than if you were traveling at relatively low speed in the lower atmosphere.

Now, I'm definitely not an expert on ablative shielding, so it's entirely possible this is the way the things actually work, but wouldn't the rate of ablation be more dependent on the heat being generated at any given time, regardless of atmospheric density?

I'm finding what this is resulting in is some very odd cases in which your shields just seem to fail to function when you need them most, but at other times you'll notice them rapidly burning off when you're traveling at relatively safe speeds in the lower atmosphere.

Edited November 17, 2013 by FlowerChild

[wasmic]

Enhancement request: Radially attachable, inflatable heat shields with decoupler.

For reference material see the Movie: "2010 the year we make contact".

Basically these would be used for aerobraking big ships, who's designs don't allow for hiding everything behind the shields that are currently availible.

Stack-attachable inflatable heat shields with decouplers. They're not radial, but they're prtty damn close to what I think you want.

EDIT: Post number 300. THIS IS SPAAAAARTAAAAAAA!