[0.17] Re-entry Heat Module and Mk-1 Pod Heat Shields

[CAPFlyer]

also this may be something that works correctly as I have no idea of the maths you guys have used to build this, but coming in on a very steep angle will negate the effects of re-entry but coming in very shallow will prolong the effects on your craft longer so you can experience the coolness of it all a little longer, not to long though of boom goes the craft shouldnt coming in steep just destroy your craft in mere seconds?

What destroys the capsule from high reentry angle is the drag, not the heat. When you hit the atmosphere at too high of an angle, the atmosphere becomes a brick wall and crushes the capsule. If you want to see the idea, take a marble or something round. Fill your bath tub with water (a sink works too, but it's easier to not splash all over the place with a tub). Throw the object lightly into the water at an angle. Note that it enters fairly smoothly with only a little splash. Now drop the object with a light push down as you drop it straight down. Notice the splash is much larger and you probably hear a very audible "plop" or "kerthunk" versus the lighter "splash". This is caused by the water's surface tension. The atmosphere works the same way. When you enter at an angle, you "shear" the surface tension allowing the capsule to slide into the atmosphere. When you drop it straight down, you try to tear it, and it pushes back, and pushes back hard, causing the surface tension to bend and then break violently. With a capsule, this bend puts massive "G-loads" on the capsule and crushes it, then when it breaks, the shockwave destroys the capsule.

[Pleborian]

does this mod destroy the craft from excessive g-forces? not something I have experienced yet, but would be another cool peril to come across regardless.

[ddavis425]

I'm not sure what changed, but the heat shield effects suddenly started working for me. It may have something to do with my angle of reentry, normally I come in very shallow but this time I reentered at about a 20 degree angle.

EDIT: Spoke too soon... now I'm back to only seeing the glowing heat shield. Not sure whether it is a graphics issue or not, but if it makes any difference my graphics card is a nVidia GeForce 550 Ti.

Edited September 27, 2012 by ddavis425

[KingAirDriver]

Glad you fixed the mod, it's awesome!

Just did a test run with two different descent angles. The first angle was somewhat shallow with initial speed approximately Mach 6 (initial atmospheric contact). This produced the nice visual effects seen below. The second angle was much steeper, with initial speed around Mach 4, and produced no effects. Neither attempt caused display/game freezes or failures.

Edit: The two photos are from the shallow angle.

[PakledHostage]

EDIT: Spoke too soon... now I'm back to only seeing the glowing heat shield. Not sure whether it is a graphics issue or not, but if it makes any difference my graphics card is a nVidia GeForce 550 Ti.

So the flames show up the first time you run it, but then don't the next time? That makes me wonder if your experience is related to the memory leak issue that some people are reporting with KSP v0.17? Maybe the game is running low on resources by the second time you re-enter? I'll try to run some tests.

Another thing you might try in the interim (admittedly a bit of a long shot) is to check your video settings in the game's settings menu. Dani-Sang sent me a PM saying: "For everyone that doesn’t see the glow effects on the parts, try turning off fallback part shaders in the game settings menu (it needs a game restart to take effect)."

[Kreuzung]

Fallback part shaders are awful in general, almost everything is displayed wrong.

Something I noticed from reading the source code is that it defines it's own temperature instead of using the part temperature simulation which is quite good from what I've heard, you'd just need to set heatConductivity and heatDissipation right on the heatshield.

EDIT:

Oh, and maybe replace the GUI with a context menu?

Edited September 27, 2012 by Kreuzung

[ddavis425]

So I found out that the effects only happen the first time I do a flight after opening the game. If I want to do another flight with those effects, I have to restart the game.

[Kreuzung]

Noticed that too, only got them once so far...

[PakledHostage]

Something I noticed from reading the source code is that it defines it's own temperature instead of using the part temperature simulation which is quite good from what I've heard, you'd just need to set heatConductivity and heatDissipation right on the heatshield.

Thanks for the tip, but the problem with that suggestion is that I have no idea what the Unity physics engine is doing in the background. From what I've seen by logging temperature data in a little home-brew data recorder module that I made, Unity's heat transfer calculations are very erratic (at least in how they are used by KSP's game engine). I don't feel that I can trust it enough to rely on it.

Oh, and maybe replace the GUI with a context menu?

That GUI was actually only intended as a debugging window. It wasn't supposed to be turned on in the release version. It should be turned off in the part.cfg file by setting "DisplayHeatShieldUI" to "False".

Edited September 27, 2012 by PakledHostage

[PakledHostage]

@ddavis425: I owe you an apology... I thought the problem that you were having was specific to your machine but I was able to duplicate it on mine this evening. The upside is that I think I have fixed it.

While I was at it, I also tweaked the logic that controls when and how intensely the plasma trail is displayed, plus I've tweaked how I destroy parachutes that are opened too early and how I destroy nearby re-entering debris. I think I also fixed a bug where a jettisoned heat shield explodes due to excessive g-forces caused by the decoupler.

I still have some testing to do, but I'll post up the new revision (v1.0.17.03) in the next day or so.

And Moach? I haven't heard from you in a few days. Did you still have some changes that you wanted to incorporate?

Edited September 28, 2012 by PakledHostage

[Subcidal]

When does the auto-steer thing take over? seems like it dosen't kick in till your some ways in to your re-entry. Would be nice if it kicked on as soon as you enter the atmosphere. And the heatshield just kinda disappears after being decoupled, Thought that was kind of odd.

Also, Just kinda dreaming here, But it would be cool to have a part that was shaped like the bottom of a capsule to attach the shield to, Possibly even having it double as a decoupler. I kind of used a pre-existing part in the Novapunch pack to make this http://i.imgur.com/tV3fAh.jpg?1 and it worked pretty good, But the part only attaches to that specific aeroshell, Something universal like that would be grand. And a series that would fit on the underside of stock plane shapes would be awesome too, Though I don't know if your current code could be carried over that easily to something with a different shape.

Edited September 29, 2012 by Subcidal

[PakledHostage]

Update:

I have just posted a new version of the re-entry heat plugin to Kerbal.net.

Version 1.0.17.03 changes:

1. Improved logic controlling when plasma trail effects are displayed.

2. Improved "explodieness" of re-entering debris.

3. Fixed a bug that prevented plasma trail effects from being displayed in some circumstances.

4. A few other minor bug fixes.

@Subcidal: The "auto-steer thing" is supposed to simulate the inherent stability of the command pod. Re-entry vehicles like the MK1-1 and MK1-2 command pods are designed to naturally orient themselves blunt end forward due to aerodynamic effects. These aerodynamic effects don't kick in until the aerodynamic forces are high enough, however

[Olsson]

Does this mod take aerodynamics or drag into effect or whatever the name is? Like I mean if I have my pod with a shield under it and then I have two wings which stick out to the sides. The heatshield will cover the pod if you look from below but the wings will stick out more, with a re-entry will these wings be pulled off, destroyed or affected in any way? I guess debris burns up unless they have a heatshield that covers them?

[ddavis425]

Thanks for the update, definitely fixed my problem with the fire trails.

[Tommygun]

You officially have a smoking hot mod now.

[kerbalboy2000]

Bravo!!! Trés bien!!! I used it and it worked so good, it even got me a super high-g!!!

[togfox]

Works like a charm. Thx!

[Olsson]

A few things:

- This mod is AWESOME.

- I don't get the small window that says Temperature, Shock and all that during re-entry sometimes. Does my heat-shield need to be in it's own stage with nothing else in it when I activate it?

- How am I supposed to know at what temperature, speed, integrity and g-force that my capsule/heatshield will break up? Any numbers on this?

- Any plans for drogues that can withstand high-speed openings and that create a small amount of drag?

[Kreuzung]

>Olsson

-YES.

-It's just for debug, ignore it. The heatshield doesn't need it's own stage, just activate it like everything else

-Try it out in true Kerbal style:sticktongue:

[Olsson]

>Olsson

-YES.

-It's just for debug, ignore it. The heatshield doesn't need it's own stage, just activate it like everything else

-Try it out in true Kerbal style:sticktongue:

Damnit! Well the heat shield breaks once the integrity meter reaches 0/to the far left right? And the faster I go, higher temperature and higher g-forces I experience the faster this integrity bar ticks down right?

[whatisthisidonteven]

Ah, this addon is awesome. If it had sounds while you were screaming through the atmosphere then it would be even more awesome

[PakledHostage]

A few things:

- This mod is AWESOME.

- I don't get the small window that says Temperature, Shock and all that during re-entry sometimes. Does my heat-shield need to be in it's own stage with nothing else in it when I activate it?

Thanks!

Check to make sure that you've got the latest version of the mod installed. I posted version 1.0.17.03 to Kerbal.net yesterday.

Among other things, I fixed an oversight where I left the little debugging GUI window turned on in the MK1-1pod heat shield's part.cfg file. You shouldn't need that window. Copy the new MK1-1 HeatShield and MK1-2 HeatShield directories into your KSP->Parts directory when you install the latest version. That should get rid of the window. If you really want to turn the little debugging GUI window, set the "DisplayHeatShieldUI" parameter in the part.cfg file to "True" (i.e. DisplayHeatShieldUI = True).

The red "Integrity" bar in the icon stack should be all you need to gauge how closely you're cutting it. It is displayed when the heat shield is activated. The spacecraft will be destroyed if the red bar reaches "empty". It will also be destroyed if the g-meter needle on the navball stays in the red for too long.

If your spacecraft are burning up during re-entry, enter a little steeper. If they are breaking up due to high g-s, enter using a shallower trajectory. But beware that the width of the survivable re-entry corridor gets narrower as your re-entry speed gets higher!

I will make a plot showing the survivable re-entry corridor in the next week or so.

Edited September 30, 2012 by PakledHostage

[Sbowyer28]

Hostage kept forgetting to ask, Does this work on planet's and moon's, Im working on an aeroshell for some Duna and Eve probes.

[PakledHostage]

Hostage kept forgetting to ask, Does this work on planet's and moon's, Im working on an aeroshell for some Duna and Eve probes.

It should work although I haven't tested it. The module calculates the re-entry effects based on the atmospheric properties of the celestial body that you're landing on. It will already behave differently depending on the temperature and density profile of each atmosphere.

My plan is to eventually define a couple of constants for each atmosphere that will change how the re-entry heating behaves. That way we could make it more or less difficult to land on certain planets and moons. (i.e. Conditions during entry into Mars' atmosphere are more extreme, for a given entry speed, than for Earth because of differing radiation heat transfer effects.) It may turn out to be pointless though, and for the time being the gas specific constants in the model are the same for every atmosphere.

[Sbowyer28]

I've been working on a Duna Entry technique for Slowing to abut 800m/s forentry, I aerobreak at about 30,000 Meters by 50,000 Meters and the atmosphere slows you down after a few orbits and you enter at about 750m/s Hope that helps if you try a Duna entry with this mod dude, Ganna try it with this mod myself soon.