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

[vardicd]

I must be doing something wrong I have yet to get a craft or debris to overheat or blow up from g's. I get temp effects, and shielding ablation during reentry, but no boom even on unshielded junk falling in.

[dave4002000]

The easy way to test the over-g is to create a rocket with a TWR of greater than 5:1. Launch at full throttle and watch the g-meter. Stuff should start exploding rather quickly.

To test the reentry, i've found that short, sub-orbital flights don't get you the speeds required to over-heat stuff. You need to get up to a full orbit and then retro back down. If you're getting shield ablation, i would say it's working correctly though. You might just be doing something right and not wrong

[jrandom]

The Problem is, this PE value is completly addicted to the mass, the drag and the stability(aerodynamic* and g-forces) of the vessel (and, of course, the incoming speed). So this PE will will just work for this POD at this speed.

*Large Vessels tend to flipp over if you go to steep into the atmosphere. If this occur in the "hot" reentry-phase, bad things will happen

Yep, it's always going to be vessel-specific, but the Mk1-2 pod is a good starting point. It's small and dense and simple. If you've got less mass or more surface area, you can aim for a higher altitude. If you've got more mass and a smaller area... you'll probably want to add enough fuel for some sort of deceleration burn before hitting atmo.

For large crafts that want to spin around, you have to specifically build your reentry stage so that the center of mass is below the vertical halfway point of your ship. I had this same issue with my 60-ton Duna lander -- I was doing multiple tests around Kerbin and it took several revisions to get the CoM low enough before I sent it to (and successfully aerobraked/landed on) Duna.

If you've got the B9 parts installed, there's a fantastic airbrake you can put on the upper part of the re-entry vessel -- those will help keep it pointed in the right direction, and they're great for bleeding off a lot of speed in thin atmospheres.

Edited August 8, 2013 by jrandom

[tygoo7]

Does this mod work for 0.21? I'm thinking of getting it.

[birrhan]

Again, entering Kerbin's SOI with a speed of 2000m/s, hitting 70km at 3800m/s.

Periapsis 20km: Total destruction of the pod. The heatshield overheats and explods, with the pod following shortly thereafter.

Periapsis 26.5km: We have a winner! Pod survives and winds up with an orbit of 25.7km x 6968km. 2/3rds of the ablating shield are left.

So when coming in that fast, 30km is too high and 20km is too low. The reentry window is around 26.5km but I don't know how narrow that window is.

Excellent work! Good to know that 3800 m/s is survivable. I am definitely trying this. For reference, your reentry mass was 6 tons or less, correct (IonCross/DRE equipment, with an SAS and parachutes on an Mk1-2 pod)?

Full reentry on the second orbit. Unfortunately, IonCross drained the rest of my battery power so I couldn't deploy chutes, but had I added a second battery, it's totally survivable. G-forces never went over 2-something.

No RTG on the command pod? Now that ASAS requires constant power to maintain heading, I never leave home without one.

[jrandom]

Excellent work! Good to know that 3800 m/s is survivable. I am definitely trying this. For reference, your reentry mass was 6 tons or less, correct (IonCross/DRE equipment, with an SAS and parachutes on an Mk1-2 pod)?

From the bottom: Heat Shield -> Pod -> Battery -> Drogue Chute. Three radial regular chutes are attached just below the drogue chute.

No RTG on the command pod? Now that ASAS requires constant power to maintain heading, I never leave home without one.

I could never find a good place to attach it. We need inline RTGs in 1.25, 2.5, and 3.75 sizes. However, the craft that the pod is attached to right up until re-entry is built with plenty of battery power and solar cells, so really I just need to slap a second battery under the drogue chute and I'm good to go.

Actually... I'll have to double-check the CO2 capacity of the Mk1-2 -- I might be able to get away with simply shutting off the CO2 scrubber when starting that second orbit.

Edited August 8, 2013 by jrandom

[Lexif]

I just started using Ioncross and by my calculations, you should be good for 10 hours without the scrubber. So if you can make sure you don't skip out of the atmosphere, you don't need to switch it on. If I didn't miscalculate, you need 166,66 of power to use the scrubber to clean out the 30 maximum CO2 of the pod. The pod has 150 power, and a mini battery ring on top gives another 200, so you can go more than 30 hours with that. Which should be enough for a large orbit after aerobraking.

I also find I don't really need SAS for the reentry. Before the atmosphere gets thick, the SAS doesn't fight much, so it should use almost no power. Once reentry really gets going, the pod orients itsself on it's own (at least with FAR). I usually only use shield, pod, docking port and three sidemounted parachutes, and never ran out of power so far.

[jrandom]

Yep, you'll notice my re-entry test pod has no extra SAS added. And since this was just a quick test before going to bed, I didn't do any CO2 and battery power calculations.

When I do full-blown missions, I sit down and work all those numbers out.

[birrhan]

From the bottom: Heat Shield -> Pod -> Battery -> Drogue Chute. Three radial regular chutes are attached just below the drogue chute.

I imagine at that speed you need each chute. From a 80 x 80 km orbit, setting Pe to ~0, I can get a similar pod through firey reentry, deploy two radial chutes, and decelerate to 160-180 m/s at around 500 m before they fill and come to a near stop. Most things are damaged, and the SAS and/or docking port may get destroyed, but everything else survives. The problem I tend to have with the drogue is finding a place for it on the command pod if I also put on a docking port.

[Frederf]

I've done tests with the Mk1 in a simple configuration: Mk16,Oct2,Mk1 and I can come in at Kerbin escape velocity anywhere in the 0-34km Pe range and only burn through about 40% of the shield. The Mk1-2 pod however I burn through the whole shield every time even for gentle 60x10 reentries (yes I know low angle is more heat). However the capsule temp peaks at ~1100 or so and I'm fine. It feels like many max temps are too low since I can reenter without a shield and just suffer the heat.

[Moose]

Has anyone managed to solve the problem that the inflatable heat shield always drags the ship so it faces the wrong way? I've got a functional design for a ship but the fact that I can't use that shield it means aerobreaking is a no go.

Searched the topic, either I failed or the search did!

[jrandom]

Has anyone managed to solve the problem that the inflatable heat shield always drags the ship so it faces the wrong way? I've got a functional design for a ship but the fact that I can't use that shield it means aerobreaking is a no go.

Searched the topic, either I failed or the search did!

I haven't tried that head shield yet, but I know that if your center of mass is above the halfway point of whatever is reentering, it'll flip around. If you have a ton of drag on the entering side but not the opposite side, you'll also flip around.

If you need a quick fix, the B9 Aerospace air brake pieces are great for keeping your craft pointed the right way.

[Jasmir]

Has anyone managed to solve the problem that the inflatable heat shield always drags the ship so it faces the wrong way? I've got a functional design for a ship but the fact that I can't use that shield it means aerobreaking is a no go.

Searched the topic, either I failed or the search did!

Personally, i use such a heatshield on _both_ ends of my big vessels. Also, i take a very smooth angle of entry, so i'll won't get a big difference between "retrograde" and "angle of attack" during the hot phase. My vessels now still flipp over after the hot entry phase, but this help a much to get rid of this heatshields after they have done their jobs.

[Moose]

Ah thankyou. I'll see if I can play around. Trying to avoid B9 if I can for now, though.

[jrandom]

Ah thankyou. I'll see if I can play around. Trying to avoid B9 if I can for now, though.

Any particular reason? It's one of the very few parts mods I kept out of all that I've tried -- very balanced, fits right in with all the rest of the pieces, and downright necessary if you build planes of any kind.

[KerbMav]

The zip-file is somewhat stuffed with files and doubled folders - what do I really need?

[boberts314]

A question for those of you better acquainted with how this mod works: Is it hypothetically possible to install Deadly Reentry without using Module Manager, or is MM being used for more than .cfg file editing here?

Any particular reason? It's one of the very few parts mods I kept out of all that I've tried -- very balanced, fits right in with all the rest of the pieces, and downright necessary if you build planes of any kind.

I actually consider the B9 parts to be kind of overpowered. The weights are about right I think, but the amount of fuels that the assorted parts carry seems sometimes almost comical compared to vanilla parts of the same volume. I'm thinking that when the tech tree comes out I will put them toward the top.

[Frederf]

I believe the reentry effects depend on MM

@REENTRY_EFFECTS[Default]:Final

{

@heatMultiplier = 25

@startThermal = 750

@fullThermal = 1150

@temperatureExponent = 1.03

@densityExponent = 0.85

}

[boberts314]

I believe the reentry effects depend on MM

@REENTRY_EFFECTS[Default]:Final

{

@heatMultiplier = 25

@startThermal = 750

@fullThermal = 1150

@temperatureExponent = 1.03

@densityExponent = 0.85

}

Can the file containing those lines not be edited manually then?

I'm in a conversation with some forumites who feel that MM shouldn't be used by modmakers. I'm trying to understand their complaints, although the arguments seem questionable to me.

[Zeroignite]

I'd like to increase g-tolerance of parts, but reduce thermal tolerance of non-heatshields. How should I edit the .cfg?

Also, it seems odd to me that the fastest rate of AblativeShield depletion isn't at max temperature, but rather at max deceleration. The shield is keeping the rest of the craft cooled by burning itself off, after all.

[velusip]

I think it's this mod making noises while attaching parts in symmetry in the VAB. Any fix for that?

[LaydeeDem]

So is there any reason my normally designed rocket gets G-Force damage before takeoff? It's really starting to piss me off.

Screenshot of rocket:

Edited August 14, 2013 by Nutt007

[The Lone Wolfling]

A question for those of you better acquainted with how this mod works: Is it hypothetically possible to install Deadly Reentry without using Module Manager, or is MM being used for more than .cfg file editing here?

It is hypothetically possible to install anything using MM without using MM.

That being said, it requires you to redistribute other people's work, as well as meaning that mod compatibility gets rather hairy (you have to manually fix config files)

[s20dan]

I'd like to increase g-tolerance of parts, but reduce thermal tolerance of non-heatshields. How should I edit the .cfg?

I've been trying to do the same but I think g-tolerance is hard coded. You can edit thermal tolerance in the custom.cfg though.

[Lexif]

This quote might help. Maybe this was tweaked later, but I guess the same principle still applies. I would vote for a parameter to make this tweakable. But if your rocket explodes on the pad it's propably a bug.

Yeah, 45G is a bit absurd. Right now, I'm computing G-force as SQRT(8 * crashTolerance), so you get roughly the following values:

crashTolerance     G-Tolerance
       6                 7
       8                 8
      10                 9
      12                10
      15                11
      18		12
      21                13
      24                14
      28                15
      32                16
      36                17
      40                18
      45                19
      50                20
      55                21
      60                22
      66                23
      72                24
      80                25

Note that these are for G-forces averaged over 1 second, and discarding any spurious spikes.