On pods flipping during re-entry

[StainX]

So the Parachute is the issue!? wrong CG on chute? what if chute get physicless flag!?

Edit: Claw already seems to have a fix for that too (HeatShieldFix?): http://goo.gl/M3T9il

Edited April 28, 2015 by StainX

[Jaffa Cookie]

Compare the pods (only the pod, no other parts) falling behavior between .25, .90 and 1.0, you'll be surprised.

Then compare with the parachute fitted.

The behavior changes a bit... my definition of a bit so more of a lot in 0.25 or .23 you could over ride the physics with SAS and land upside down with parachute were as in .90 you couldn't unless you really fighted it really hard. Also talking about flipping whilst doing a gravity turn my ship usually flips after taping and i MEAN just a tap then it completely flips out despite resisting it.

Also at the start someone said you needed to get something to make the changes, You don't. or at least i don't. I guess it could be operating systems if you do need it to edit it.

- - - Updated - - -

Killed Val with the same issue last night: pod with service bay and Science Jr flipped ends and exploded.

I'm wondering whether it's a bug or realism though; I haven't had the issue with capsules by themselves, and I don't recall any real life space programs that had long skinny top heavy re-entry vehicles... Vostok, Soyuz, Mercury, Gemini and Apollo all had short squat capsules.

I'm wondering whether it's a bug or just bad (ie unrealistic) design and re-entry trajectories combined with false expectations created by the old aero system...

It's most likely that as if you had it so that it's Centre of mass was low means that it'll want to have it like that. However it would be difficult as there is a more aerodynamic place the top.

Edited April 28, 2015 by Jaffa Cookie

[tater]

Compare the pods (only the pod, no other parts) falling behavior between .25, .90 and 1.0, you'll be surprised.

Then compare with the parachute fitted.

I can't test this right now, can you just post the findings? What about the same 3 tests with a heat shield?

[Theodore82]

I think that's the bug. And I think I didn't see it because my return craft was 3 parts: Pod, chute, shield. If you have a pod, with a service bay, with a heat shield then the COM is all wonky.

Horseman, (and OP):

I've come tearing in at 3500km/s+ from a botched Mun return where I burned (excessively) on the normal at closest point to Mun to get aero capture return with hardly any fuel for slow down. I hit around 25km and it took me 3 passes to slow down enough for capture.. (4 if you count the one I time warped through)

The return vessel was as follows:

Mk1 pod with 2 chutes (vertical)

Reactionwheel with 2 chutes (horizontal)

Science Junior with 4x thermometers attached

Science Junior

New Small cargo bay with 2 goo canisters and 6 batts

New small cargo bay with 12 batts

Heat shield

An ugly beast - but didnt flip out at all, though I admit I released one of the 'horizontal' aligned chutes while shrouded in flames as I was getting worried for Jeb - who - unsurprisingly was smiling and laughing in his normal way.

[Chryseus]

The chute seems to be the problem, without it or using a small nose cone it flies perfectly straight with SAS off.

[EladDv]

if it is the chute this is even more concerning that the bug went through QA and Exp. something is wrong there- it's not a Kraken drive bug that only activates rarely and needs some spacial engineering to work this is core basic level gameplay you cant overlook this kind of bug easily.

[Akadion]

There *is* a very small window where SAS can keep you on track for almost no energy expenditure (<10 for the Mk1 with just a heatshield and Mk16 chute, on a mun-return trajectory with periapsis ~21km). But then I turned physics on for the heat shield and the landing was so much nicer. It may not be entirely realistic to completely dead-stick a landing - I did a test with the physicsless heatshield and rotated at a constant rate through the landing, like Apollo did, and it worked fine. Nothing blew up, nothing even got terribly warm and the capsule remained pointed in roughly the right way. But I had to use my joystick, couldn't get the right rate of spin with my keyboard, and it ate up a *lot* more power than using SAS.

[Kerano]

I'm also surprised this bug got through QA. You only need to reenter the atmosphere once to notice the problem.

Ah well, hopefully it will be fixed with 1.0.1.

[Dizzle]

I think the solution is to enable heatshield mass for all sizes, as well as increasing the 1.25m heatshield's mass to 0.2 or maybe 0.3. It seems to take a lot to flip the Mk.1-2 over, thankfully.

[Superfluous J]

I'm also surprised this bug got through QA. You only need to reenter the atmosphere once to notice the problem.

Ah well, hopefully it will be fixed with 1.0.1.

If the Twitch streamers this weekend were any indication, it's possible that nobody actually make it so far through the game as to need to re-enter the atmosphere.

[thedoktorj]

I just experienced this bug on a return mission from the Mun. I had read something about it earlier so I was very careful to keep my reentry very shallow. I did 3 aerobraking passes at 50,000 feet starting the final descent at about 2200 m/s, at first all was well, my ablator was going down, I had SAS on, and at around 26000 meters the oscilations started. I did all I could to keep the craft from flipping, but in the end, it flipped at around 24000 meters. The only thing I could think to do was to pull my chutes, and strangely enough, despite the cloud of superheated plasma surrounding my craft, the chutes deployed, flipped me around and saved the 1+ hour flight from disaster. I had a quick save, so after exiting and backing up my persistent save, I went back and tried several more times, no matter what I did, this happened. I tried controlling it manually, not controlling manually, sas, no sas, no matter what it flipped and exploded, unless I pulled the chutes. This doesn't exactly seem like a fix, but it does seem to help. Hopefully Squad will fix this quickly, it is a pretty game breaking bug. In the mean time, I will try the physics fixes listed above.

[OtakuD]

yeah chutes seem to help me too, so strange does anyone know if this is working as intended or a real bug? Sometimes had to engage RCS during entry to try fight the forces but wow is it nerve racking.

[Superfluous J]

yeah chutes seem to help me too, so strange does anyone know if this is working as intended or a real bug? Sometimes had to engage RCS during entry to try fight the forces but wow is it nerve racking.

It's been announced that it will be corrected in the hotfix. Until then, use the modulemanager config (not mine, just reposting it here for visibility:

@PART[HeatShield*]
{
@PhysicsSignificance = 0
}