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

[Starwaster]

lajoswinkler: as Starwaster mentioned in one of the updates, Jool's atmosphere is not very dense, so while you're going insanely fast and thus flash-heat what air there is, the air being hot doesn't mean lots of heat transfer to you.

(which is a Good Thingâ„¢ when doing a Jupiter aerobrake maneuver in Real Solar System....)

I have two things to report.

Went to Laythe today. Aerobraked at Jool. Plasma and reentry sound start instantly upon crossing 138 km. There is absolutely no transition. It's as someone turned on a switch. The shield was ok. Other parts of the ship, too, as they were all inside the reentry shadow of the shield.

Nathan answered the important bit but regarding the swiftness of the transition, there's not a whole lot that can be done with that given a stock atmosphere. I forget the exact number but stock (or legacy) atmosphere cuts out when pressure has dropped to a particular value. Just stops abruptly. KSP does have support for more realistic atmospheres but it does not make use of them at this time. (just like it has drag models that take into account orientation and conical and cylindrical shapes but doesn't make use of those either)

Real Solar System btw makes use of the new atmosphere model which uses curve data and all of the planets with atmospheres have atmosphere curves which simulate the atmosphere more realistically and don't cut out as abruptly. (though there is still an arbitrary cut off point because there is a point at which the air just gets so thin that it has no game value other than to prevent non-phys time warps)

Edited October 21, 2014 by Starwaster

[NathanKell]

when e^(-height_in_km / scaleHeight_in_km) < 1e-6, pressure drops to 0. *No matter the pressure multiplier* so Eve will have one *heck* of a sharp transition (because it has a high multiplier but not a terribly high scaleheight).

[lajoswinkler]

OK, but why is my ship overheating if the shield is covering all of it? It's a tested design. The first thing that should fail is the shield, yet the parts of the ship clearly protected are behaving as there isn't any shield at all. They do not show plasma trails, but upon right clicking, you can see the temperature is skyrocketing. That seems like a bug to me.

[Starwaster]

OK, but why is my ship overheating if the shield is covering all of it? It's a tested design. The first thing that should fail is the shield, yet the parts of the ship clearly protected are behaving as there isn't any shield at all. They do not show plasma trails, but upon right clicking, you can see the temperature is skyrocketing. That seems like a bug to me.

Yeah ok now you're losing me here. If your design is tested and it works then it works. It's not going to suddenly stop working on one planet only and treat some parts as unshielded but not others. I'm just not buying that.

Screenshots and logs. And maybe a craft file that clearly demonstrates the problem. (stock parts please)

[Cleric2145]

Just out of curiosity (I took a hiatus from KSP since .23 and rejoined at .25 so I missed a few updates to DRE), have the mechanics for heat dissipation/ablation been totally reworked? Previously, the hotter the reentry, the quicker your heat shield would ablate, and the quicker it would ablate (i.e. evaporate), the more the actual shield's temperature would drop (evaporation causing a drop in temperature.) Once the shield was depleted, its temperature would start rapidly climbing until it over heated and shattered with the rest of the craft soon following suit.

In the current version (which I've only tested in the Kerbin atmosphere thus far), a different series of events has been occuring. As reentry gets hotter, the ablation rate also climbs--just as before. Except now, the temperate seems to climb with the ablation, until the shield fully ablates (which previously would only happen on a botched reentry profile but now regularly happens) at which point the temperature plummets from ~1800C down past ~800C. Am I just lucky in timing the shield running out with deccelerating enough to not overheat, or is this intentional?

Additionally, I would play with the Shockwave Exponent and multipliers at around 1.07, but now with the both of them set at 1.00 I seem to be hard pressed to keep my shield from depleting by the end of reentry, where previously I would hit maybe 25% on a hard reentry. I very well may be totally misunderstanding all of the values' effects, but there definitely seems to be something different. Running out of AS would previously be a death sentence, but it wouldn't happen unless I came in too steep or spent too long in the mid atmosphere burning it off.

[Starwaster]

Just out of curiosity (I took a hiatus from KSP since .23 and rejoined at .25 so I missed a few updates to DRE), have the mechanics for heat dissipation/ablation been totally reworked? Previously, the hotter the reentry, the quicker your heat shield would ablate, and the quicker it would ablate (i.e. evaporate), the more the actual shield's temperature would drop (evaporation causing a drop in temperature.) Once the shield was depleted, its temperature would start rapidly climbing until it over heated and shattered with the rest of the craft soon following suit.

In the current version (which I've only tested in the Kerbin atmosphere thus far), a different series of events has been occuring. As reentry gets hotter, the ablation rate also climbs--just as before. Except now, the temperate seems to climb with the ablation, until the shield fully ablates (which previously would only happen on a botched reentry profile but now regularly happens) at which point the temperature plummets from ~1800C down past ~800C. Am I just lucky in timing the shield running out with deccelerating enough to not overheat, or is this intentional?

Additionally, I would play with the Shockwave Exponent and multipliers at around 1.07, but now with the both of them set at 1.00 I seem to be hard pressed to keep my shield from depleting by the end of reentry, where previously I would hit maybe 25% on a hard reentry. I very well may be totally misunderstanding all of the values' effects, but there definitely seems to be something different. Running out of AS would previously be a death sentence, but it wouldn't happen unless I came in too steep or spent too long in the mid atmosphere burning it off.

Some reworking has occurred and things are a little hotter overall, but some of what you're describing is just timing. The amount of heat is dependent on the temperature of the shockwave created as your craft hurtles through the atmosphere. The shockwave is created by air bunching up in front of you. (front being defined as towards your velocity vector). The temperature of the shockwave is about equal to your velocity in meters per second in Kelvins. (to convert to Celsius, subtract 273). The amount of heat that is actually picked up by your craft is dependent on the density of the air outside. It's entirely possible to think you've made it because the shockwave temperature is rapidly dropping but then suddenly your hull starts heating up because the air has finally become dense enough that enough heat is getting through to push your temperature up and rapidly deplete your shield.

[lajoswinkler]

Yeah ok now you're losing me here. If your design is tested and it works then it works. It's not going to suddenly stop working on one planet only and treat some parts as unshielded but not others. I'm just not buying that.

Well that seems to be the case. Weird, huh?

Screenshots and logs. And maybe a craft file that clearly demonstrates the problem. (stock parts please)

There aren't just stock parts here (the tanks and the main shield are made by Procedural Parts mod, solar panels are by Near Future Electric, there's one ALCOR pod and an original Mk1 Legacy pod; it was built in three steps and strutted using KAS afterwards), but here's the screenshot of the ship anyway.

You'll notice there's an RTG sticking out of the shielded cone. It stays fine at Jool aerobraking, but to be certain it's not gathering heat and transfering it to any part of the ship, I've removed it after the initial braking incident at Laythe. It didn't change anything.

The ship was supposed to enter Laythe's orbit, deploy a returnable lander and then return to Kerbin after the lander returns the Kerbals.

Just out of curiosity, is the shielding area in stock KSP the form of a cone or a cylinder, is the border sharp or has a penumbra, and does DRE change any parameters that might affect it? My ships can have a length more than 25 m, so perhaps that's the problem.

Here's two more screenshots of the ship to show the shield is large enough to cover everything.

(Ignore the silly Kerbal yoyoing a probe. )

And last question - is there a way to disable the heating temporarily?

Edited October 21, 2014 by lajoswinkler

[Starman4308]

Well that seems to be the case. Weird, huh?

This might be a silly question, but do you still have ablative material on the heatshield? It's possible your Jool aerobrake is wearing the heatshield down to its structural base, at which point the shield is just another part, unable to really prevent heat from transferring into other parts of your craft.

[lajoswinkler]

This might be a silly question, but do you still have ablative material on the heatshield? It's possible your Jool aerobrake is wearing the heatshield down to its structural base, at which point the shield is just another part, unable to really prevent heat from transferring into other parts of your craft.

I do. Jool didn't remove any of it...

Others have suggested it might be Laythe's aditional atmosphere components, but I don't think that's modelled, it sounds weird to me. Air in KSP is one thing which has or has not IntakeAir property.

[Starwaster]

Planets do have differing properties to their atmospheres now which does affect heating. Jool is mostly hydrogen so less dense and less heating for a given atmospheric pressure value.

Laythe has the same value as Kerbin.

Now now then as to parts shielding each other:

each update, a ray is cast from an objects center along its flight path. If the ray strikes anything within 10 meters the part is considered shielded. If the distance from its center to its nearest edge along that ray is more than 10 meters it is Unshielded.

In the case of fairings, if FAR is installed then it relies on FAR to tell it if the fairing protects a part. Otherwise the ray sat method is used. I consider fairing detection to be unreliable in both cases to varying degrees depending on method and whether or not the fairings are procedural.

Specifically, ray casting fails to find any colliders in the fairings frustum.

[jrandom]

Is there a way to alter the raycast difference test, eg. configurable as a setting? Allowing users to configure that would allow them to build some pretty interesting reentry/aerobrake vessels that should work but have a large shield more than 10 meters from the objects being shielded.

[Starwaster]

Is there a way to alter the raycast difference test, eg. configurable as a setting? Allowing users to configure that would allow them to build some pretty interesting reentry/aerobrake vessels that should work but have a large shield more than 10 meters from the objects being shielded.

If you mean is something like that possible now, no it's not.

If you're asking if it could be added, yes pretty easily. I might do it too. Probably wont expose it to the in-game debug window which looks a little crowded as it is though.

EDIT:

On the subject of the settings button that I'm putting in, no progress on that right now. When I put it in, it has to be done in a way that it and the current debug window tie in. It won't do to have two interfaces maintaining and writing different data to to the same group of settings.

So what's ultimately going to happen is that for each difficulty setting there will be a separate group of DRE settings. If you're in normal mode then the default configuration is used. Two others will be added for easy/hard and depending on which difficulty you're set to, using the debug window will make changes to that specific group. So if you're on easy mode and you open the debug window then you'll actually be making changes to the DRE config for Easy. All three groups will be saved to the custom.cfg file as the default config currently is now.

Edited October 21, 2014 by Starwaster

[jrandom]

I'd be fine with the raycast distance only being settable by editing a .cfg file. I'm no stranger to text editors.

[nanowinner]

I have this small problem where the icon of DeadlyReentry while at the Space Center is a white square, as if it's missing. But I haven't tampered with the mod at all.

[Starwaster]

I have this small problem where the icon of DeadlyReentry while at the Space Center is a white square, as if it's missing. But I haven't tampered with the mod at all.

That's a feature that I'm working on. It wasn't supposed to activate yet. If you redownload it go away.

[nanowinner]

That's a feature that I'm working on. It wasn't supposed to activate yet. If you redownload it go away.

Was that fixed in 6.2.1?

[Starwaster]

Was that fixed in 6.2.1?

No it was removed until it's ready to go

[Toshogu]

welp, I did a third fresh install of everything KSP, FAR, and DR.

What ever it was has cleared itself up, so I guess it was a bad install of something. I'll remember not to come here when I suspect something is wrong. You can debug your mod without my help.

[DivisionByZero]

No it was removed until it's ready to go

So... I had been setting the thing to "hard". Is it not doing anything in the versions that had it?

[NathanKell]

Correct!

10char

[Starwaster]

welp, I did a third fresh install of everything KSP, FAR, and DR.

What ever it was has cleared itself up, so I guess it was a bad install of something. I'll remember not to come here when I suspect something is wrong. You can debug your mod without my help.

Thank you for demonstrating what I and several others told you all along: It was not a problem with Deadly Reentry.

So... I had been setting the thing to "hard". Is it not doing anything in the versions that had it?

Sorry, it wasn't doing anything. (not yet) The next time you see that button it will be functional.

[N8-Toe]

So Im using this with FAR, RT and such. also I am using B9 which I wanted to know if this works with B9. but I wanted to ask for advice regarding Probes and their re-entry. Any advise for early career probe returns?

[Starman4308]

So Im using this with FAR, RT and such. also I am using B9 which I wanted to know if this works with B9. but I wanted to ask for advice regarding Probes and their re-entry. Any advise for early career probe returns?

If you're using RemoteTech, I would advise that you ensure your heatshield is oriented the proper way significantly before you hit mid-atmosphere: your antenna might break off in reentry. It also helps to have your chutes armed well ahead of time*. Otherwise, it's the same as ever: re-enter at a shallow angle, perform a lifting re-entry if you so wish, and double-check that your heat shield is facing the right way.

*If using stock, just tweak your chutes at the VAB to only open at high pressure; if using RealChutes, you can set low deployment altitude. Otherwise, you risk either not having contact with the probe to deploy chutes manually, or you will have your chutes burn up because they decided that the middle of re-entry was a perfect time to deploy. I've only ever done one RT re-entry: it was a suborbital flight with no available comm links past apoapsis. Fortunately, aerodynamics corrected the alignment of the probe from about 30 degrees off to face re-entry directly, and my parachutes deployed exactly as planned.

[jrandom]

I've got a little custom .cfg files that increases the heat tolerances for spaceplane parts. I'd like to add heat shield module sections for replicating the behavior of space shuttle thermal tiles but have no idea what numbers I should use in ModuleHeatShield. Any advice, or references I can go look at? (I asked in the RO thread, but... that didn't go over very well.)

[Starwaster]

I've got a little custom .cfg files that increases the heat tolerances for spaceplane parts. I'd like to add heat shield module sections for replicating the behavior of space shuttle thermal tiles but have no idea what numbers I should use in ModuleHeatShield. Any advice, or references I can go look at? (I asked in the RO thread, but... that didn't go over very well.)

You don't say if it's for stock or RSS. If stock, set reflection to 0.25.

direction I think to 0, 1, 1 (on iPhone and can't double check)

if it's for RSS you might get away with the same values for a lightweight plane. Heavies like the KSO25.....Well check the last few pages on the kso thread and see the kso25 config I linked to. I also posted it here a few pages back. If you can't find it I'll repost it when I get back to computer.