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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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kalizec

kalizec

Posted
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Is it possible that DRE currently doesn't have a sane way of surviving reentry to Eve?

I've currently got a probe 'stuck' in orbit around Eve and I've tried numerous things, but all end up in destruction.

The probe weighs approx 4000kg (including shields), has a diameter of 1,25m.

It has two 2,5m heat-shields attached to it (stacked on top of each other).

It's deorbited from just above the atmosphere, which results in a velocity of around 3100m/s.

The target periapsis is 78500m which results in a nice 'skip'.

Any and all reentries end in the exact same way, the heat-shield overheats and explodes.

The next heatshield only lasts another second or so and also explodes.

It seems to me the problem is the heat-shields don't have a high enough maximum temperature.

The only work-around I can imagine is retro-rockets. But as Eve is supposed to be the equivalent of Venus

and the Russions managed multiple landings using heat-shields during the 70's I feel that DRE should provide heat-shields that allow for landing on Eve.

I've tried tampering with the part-cfg's. But even raising the maxTemp value of the heat-shields to 50000 still only results

in an ingame maxTemp of 2500 and that simply isn't enough to survive reentry.

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Ralathon

Ralathon

Posted
Posted
Is it possible that DRE currently doesn't have a sane way of surviving reentry to Eve?

I've currently got a probe 'stuck' in orbit around Eve and I've tried numerous things, but all end up in destruction.

The probe weighs approx 4000kg (including shields), has a diameter of 1,25m.

It has two 2,5m heat-shields attached to it (stacked on top of each other).

It's deorbited from just above the atmosphere, which results in a velocity of around 3100m/s.

The target periapsis is 78500m which results in a nice 'skip'.

Any and all reentries end in the exact same way, the heat-shield overheats and explodes.

The next heatshield only lasts another second or so and also explodes.

It seems to me the problem is the heat-shields don't have a high enough maximum temperature.

The only work-around I can imagine is retro-rockets. But as Eve is supposed to be the equivalent of Venus

and the Russions managed multiple landings using heat-shields during the 70's I feel that DRE should provide heat-shields that allow for landing on Eve.

I've tried tampering with the part-cfg's. But even raising the maxTemp value of the heat-shields to 50000 still only results

in an ingame maxTemp of 2500 and that simply isn't enough to survive reentry.

Have you tried a really low periapsis? Like, -100km or so? If you overheat you generally enter too shallow. A ship's heat dissipation is based on how fast the shield is ablating. It doesn't ablate all that fast in the upper atmosphere, so if you spend too long in the upper reaches you can't get rid of the heat and stuff overheats.

If you have FAR you can try a lifting reentry later on. So dive deep into the atmosphere at first so you don't overheat, then pitch up to generate some lift so the G-forces don't kill you.

Cool science factoid: The venera 4 probe (first to land on venus) peaked at 300G's during landing. But I don't expect kerbal probes can withstand that.

If all else fails I suggest tweaking the config file for the heat shield so you ablate and dissipate more at higher temperatures.

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Starwaster

Starwaster

Posted
  • Author
Posted
Is it possible that DRE currently doesn't have a sane way of surviving reentry to Eve?

I've currently got a probe 'stuck' in orbit around Eve and I've tried numerous things, but all end up in destruction.

The probe weighs approx 4000kg (including shields), has a diameter of 1,25m.

It has two 2,5m heat-shields attached to it (stacked on top of each other).

It's deorbited from just above the atmosphere, which results in a velocity of around 3100m/s.

The target periapsis is 78500m which results in a nice 'skip'.

Any and all reentries end in the exact same way, the heat-shield overheats and explodes.

The next heatshield only lasts another second or so and also explodes.

It seems to me the problem is the heat-shields don't have a high enough maximum temperature.

The only work-around I can imagine is retro-rockets. But as Eve is supposed to be the equivalent of Venus

and the Russions managed multiple landings using heat-shields during the 70's I feel that DRE should provide heat-shields that allow for landing on Eve.

I've tried tampering with the part-cfg's. But even raising the maxTemp value of the heat-shields to 50000 still only results

in an ingame maxTemp of 2500 and that simply isn't enough to survive reentry.

Stock Eve or RSS? If RSS then your shield wont work very well. Max temp wont really help, you have to edit the ModuleHeatShield dissipation curve. Change the second key (not sure what original value is) to key = 800 1260

for instance mine looks like


dissipation
{
    key = 300 0
    key = 800 1260
}

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Frederf

Frederf

Posted
Posted
Is it possible that DRE currently doesn't have a sane way of surviving reentry to Eve?

I've currently got a probe 'stuck' in orbit around Eve and I've tried numerous things, but all end up in destruction.

The probe weighs approx 4000kg (including shields), has a diameter of 1,25m.

It has two 2,5m heat-shields attached to it (stacked on top of each other).

It's deorbited from just above the atmosphere, which results in a velocity of around 3100m/s.

The target periapsis is 78500m which results in a nice 'skip'.

Any and all reentries end in the exact same way, the heat-shield overheats and explodes.

The next heatshield only lasts another second or so and also explodes.

It seems to me the problem is the heat-shields don't have a high enough maximum temperature.

The only work-around I can imagine is retro-rockets. But as Eve is supposed to be the equivalent of Venus

and the Russions managed multiple landings using heat-shields during the 70's I feel that DRE should provide heat-shields that allow for landing on Eve.

I've tried tampering with the part-cfg's. But even raising the maxTemp value of the heat-shields to 50000 still only results

in an ingame maxTemp of 2500 and that simply isn't enough to survive reentry.

Are you using FAR? What is your Cd?

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kalizec

kalizec

Posted
Posted (edited)
Have you tried a really low periapsis? Like, -100km or so? If you overheat you generally enter too shallow. A ship's heat dissipation is based on how fast the shield is ablating. It doesn't ablate all that fast in the upper atmosphere, so if you spend too long in the upper reaches you can't get rid of the heat and stuff overheats.

So far I've tried the following periapses: 78k5 (skips), 78k, 77k, 76k, 75k, 74k, 70k, 60k, 50k, 30k, 10k, -10k, -30k, -50k, -75k, -100k, -150k, -200k.

All result in overheating and none even manage to ablate more than 5% of the heat-shield.

If you have FAR you can try a lifting reentry later on. So dive deep into the atmosphere at first so you don't overheat, then pitch up to generate some lift so the G-forces don't kill you.

I will try this somewhere in the near future, but first I'd like to determine what's actually required to survive an uncontrolled entry.

Cool science factoid: [snip]
Is indeed cool :)
Stock Eve or RSS?
Stock Eve.
Max temp wont really help, you have to edit the ModuleHeatShield dissipation curve. Change the second key (not sure what original value is) to key = 800 1260

Thank you. I will try that next.

Are you using FAR? What is your Cd?

Nope, eyeing it for the future though.

My Cd? Not familiar with that term. If you mean Shockwave Exponent then it's 1.12.

Edited by kalizec
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Saaur

Saaur

Posted
Posted (edited)

I've been playing this game so long I thought I knew what I was doing. But I just installed FAR and DR 1.3 and I can't even launch my first atmospheric craft in career mode because there are no heatshields unlocked.

Am I using a wrong version? Was there a config change I was supposed to make to enable such things in career mode? Help! :(

EDIT: To make matters worse, I just found out the starting parachute won't allow the smallest possible rocket to land safely. Wtf?

Edited by Saaur
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NathanKell

NathanKell

Posted
Posted

FlowerChild: Aw, thanks so much! :]

When I reorganize the OP, mind if I put a link to your mod there?

z26: Yup, if not physically significant, parts are ignored.

ExEvolution: as wasmic says, could be anything I'm sorry to say.

BC000001: if you're playing on stock Kerbin (non-RSS) but want a nice challenge, use FlowerChild's configs in the post right above yours.

kalizec: you're using a shockwave exponent, which means you need stronger shields than come standard with DRE. Get FlowerChild's configs, on the previous page.

quasarrgames: Not sure what you mean here. What would the slider change?

Saaur: Note that the Mk1 pod comes with an integral heat shield. No idea about parachutes though.

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FlowerChild

FlowerChild

Posted
Posted
FlowerChild: Aw, thanks so much! :]

When I reorganize the OP, mind if I put a link to your mod there?

Not at all man. Although it makes me think that I probably should have asked you if this whole "required mod" thing I'm doing is cool with you, and if it's all right that I'm passing around links to the DR thread to people :)

But yeah, feel free to provide a direct link to that config file. I may ping you in the future if any further balancing is required on the late game heat shields, as that's something I'm in the process of play testing in my own mod right now. Well, "late game" in terms of the way I think of them with my own tech progression as atmospheric entries on other planets is something I've pushed way up towards the end of the tech tree :P

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Frederf

Frederf

Posted
Posted
Nope, eyeing it for the future though.

My Cd? Not familiar with that term. If you mean Shockwave Exponent then it's 1.12.

Cd is C coefficient for d drag. It's a ratio of your drag vs. a reference plane of the same cross sectional area and would only be a number you'd have access to if using FAR. I recently came across buggy situations where my Cd and thus total drag was super low so I spent forever at high speed during DRE reentry which was practically impossible to survive. Since you're not using FAR and/or procedural fairings I doubt that's what's happening to you.

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NathanKell

NathanKell

Posted
Posted

FlowerChild: Oh, it's totally fine with me! That's what DRE is there for, to be used. :)

I plan to link to that post so people get your explanation too, but if you have a full pack up somewhere I can link to that too.

Saaur: If you're running with a shockwave exponent or multiplier of > 1.0, you need FlowerChild's heat shield patch. It's expected you'll burn up using heatshields rated for stock DRE on stock Kerbin if you use non-stock stats....

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FlowerChild

FlowerChild

Posted
Posted

I plan to link to that post so people get your explanation too, but if you have a full pack up somewhere I can link to that too.

Well, the post I made about it contains a link straight to the .cfg file for ease of installation, and I'm totally cool with you linking to that elsewhere as well. Do what you want with it man, I'm good with it :)

One thing I wanted to mention is that I've also modified the descriptions for the different heat shields within my own mod and it corresponds to the information I provided within that post as to the purpose of each shield. If you like, I can include those in the .cfg file as well as it may save you some tech support ;)

I didn't include them in the original though, as I wasn't certain the extent of modifications which was appropriate. Anyways, let me know if they'd be of use to you and I'll post them up if so.

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erbmur

erbmur

Posted
Posted (edited)

I think I may have found a bug? I was hoping somebody else could confirm it as well?

When in space, and pod runs out of power, temperature reading reads something like "nan", which is correct, but during re-entry, even though the capsule blazes through the atmosphere, not a single unit of ablative shielding is removed.

It's almost as if the lack of power causes the mod to shut down?

EDIT: Nevermind, just restarted the game and it seems to have fixed itself. Probably a loading issue of some kind.

Edited by erbmur
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ZobrAA

ZobrAA

Posted
Posted (edited)

So, I have my custom Mk1-2 pod, seamlessly welded with clamp-o-tron and heatshield:

EeQexCH.png

PART
{
// --- general parameters ---
name = ZobrA_Mk1-2-ZPod
module = Part
author = C. Jenkins / nhnifong / ZobrA

// --- asset parameters ---

MODEL
{
	model = Squad/Parts/Command/Mk1-2Pod/model
	position	=	0.0, 0.0, 0.0
	rotation	= 	0.0, 0.0, 0.0
	scale		=	1.0, 1.0, 1.0
}	

MODEL
{
	model = Squad/Parts/Utility/dockingPort2/model
	position	=	0.0, 1.15, 0.0
	rotation	= 	0.0, 0.0, 0.0
	scale		=	1.0, 1.0, 1.0
}

MODEL
{
	model = DeadlyReentry/Parts/deadlyReentry_2.5Heatshield/model
	position	=	0.0, -0.66579, 0.0
	rotation	= 	180.0, 0.0, 180.0
	scale		=	1.3, 1.3, 1.3
}


scale = 1
rescaleFactor = 1

// --- node definitions ---
// definition format is Position X, Position Y, Position Z, Up X, Up Y, Up Z
node_stack_top = 0.0, 1.4328832, 0.0, 0.0, 1.0, 0.0, 1 //default - slimfix + dockport
node_stack_bottom = 0.0, -0.35079, 0.0, 0.0, 1.0, 0.0, 2 //default - slimfix to 2.5m
node_stack_chute = 0.0, 1.25, 0.0, 0.0, 1.0, 0.0, 0
node_stack_esctower = 0.0, 1.28, 0.0, 0.0, 1.0, 0.0, 0


// --- editor parameters ---
cost = 1800
category = Pods
subcategory = 0
title = Mk1-2-Z Command Pod
manufacturer = ZobrA Welding Workshop //Kerlington Model Rockets and Paper Products Inc.
description = Improved version of Kerlington's regular Mk1-2 Command Pod with properly installed heatshield, build in docking port and frontal VDS-camera for precise docking. //This modern cockpit is designed to be fully re-useable. Its spacious cabin can hold a maximum of 3 crew.
// attachment rules: stack, srfAttach, allowStack, allowSrfAttach, allowCollision
attachRules = 1,0,1,1,0

// --- standard part parameters ---
mass = 4.05
dragModelType = default
maximum_drag = 0.20
minimum_drag = 0.15
angularDrag = 2
crashTolerance = 45
maxTemp = 1700 //for Deadly Reentry // orig 3400

vesselType = Ship

// --- internal setup ---
CrewCapacity = 3

INTERNAL
{
  name = PodCockpit
}

MODULE
{
	name = ModuleCommand
	minimumCrew = 1
}

RESOURCE
{
	name = ElectricCharge
	amount = 150
	maxAmount = 150
}

MODULE
{
	name = ModuleSAS
}

MODULE
{
	name = ModuleReactionWheel

	PitchTorque = 15
	YawTorque = 15
	RollTorque = 15

	RESOURCE
	{
		name = ElectricCharge
		rate = 1.2
	}
}

MODULE
{
	name = ModuleDockingNode
	referenceAttachNode = top
	nodeType = size1
}

MODULE
{
    name = MuMechModuleHullCameraZoom
    cameraName = Mk1-2-ZPodDockCam
    cameraForward = 0, 1, 0
    cameraUp = 0, 0, -1
    cameraPosition = 0, 1.29, -0.13
    cameraFoVMax = 60
    cameraFoVMin = 5
}

MODULE
{
	name = ModuleHeatShield
	direction = 0, -1, 0 // bottom of pod
	reflective = 0.05 // 5% of heat is ignored at correct angle
	ablative = AblativeShielding
	loss
	{ // loss is based on the shockwave temperature (also based on density)
		key = 650 0 // start ablating at 650 degrees C
		key = 1000 320 // peak ablation at 1000 degrees C
		key = 3000 400 // max ablation at 3000 degrees C
	}
	dissipation
	{ // dissipation is based on the part's current temperature
			key = 300 0 // begin dissipating at 300 degrees C
			key = 500 90 // maximum dissipation at 500 degrees C
	}
}
RESOURCE
{
	name = AblativeShielding
	amount = 1000
	maxAmount = 1000
}

}

All seems to be cute, but temperature on this pod calculates completely wrong on reentry:

9jUDnJM.png

vFV3cXL.png

Can anyone help me with this strange bug? Maybe DR just hates welded parts? ^_^

Edited by ZobrAA
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Andon

Andon

Posted
Posted
Can you add a drogue chute that can withstand the heat of reentry and will help with keeping a craft oriented right?

Such a chute would be near-impossible to make in reality, but there are other ways to do this.

The B9 pack has airbrakes - putting these to the rear of the craft and deploying them on re-entry will help with keeping it lined up properly.

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ferram4

ferram4

Posted
Posted

@ZobrAA: IIRC, DRE uses raycasting to detect whether a part is exposed to the airflow. What's happening here is that the part is raycasting from the part origin (in the pod) and is hitting the heat shield model (which is still part of the pod) and so is being assumed to be shielded. I guess it could be fixed code-wise by going until the raycast hits a different part, but for now the welding is a problem.

You need to understand that most plugins are designed around specific assumptions about parts to make the calculations simpler and faster. Welding allows you to easily violate those assumptions and break the plugin. In this case, the assumption would be that each part has only one collider, which happens to contain the part origin.

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