Flight Not slowing down on reentry

[The Aziz]

Reported Version: v0.1.3 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Win10 | CPU: i7-10700KF | GPU: RTX2060 | RAM: 32GB

 

Detached the fuel tank and was ready to deploy parachute (that didn't really deploy), prepared for hard landing but the capsule went back up??

As in the attached video.

 

Included Attachments:

Desktop2023_06.22-19_49_36_02_DVR.mp4

Ksp2.log

[RalphKerman]

Reported Version: v0.1.3 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Win 10 | CPU: Intel Core i7-6700K | GPU: 2 x NVIDIA 1080 | RAM: 32 GB

 

No command pod gets slowed down on descent through the atmosphere of Kerbin, they even gain velocity as if no atmosphere was present.

Reproducable: yes, tried it with all pods after multiple game restarts (of course each time with a brand new campaign file, deleted all saves when patch came out)

Build any rocket, send it up and decouple, turn the command pod retrograde -> you will see no slow down at all, just as if there was zero drag

 

Included Attachments:

[brettpersson]

Reported Version: v0.1.3 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 11 | CPU: i9-13900HX | GPU: RTX4080 | RAM: 32gb

 

I do a burn to reenter Kerbin and my capsule just keeps gaining speed on the way down.  There doesn't seem to be any friction when entering the atmosphere.   I continue to travel to fast to use parachutes.  I even tried reentering the atmosphere with a longer burn to slow me down and I still increased speed the whole way down.  Once I started to slowly slow down at an altitude of 8k.

 

Included Attachments:

[RedderThanMisty]

Having the exact same issue here.

I was flying in a standard mk1 command pod with a parachute and heatshield, Launch seemed alright, but re-entry, coming in at about 2km/s was very janky.

Pod always wanted to lean heavily towards one side, even with SAS.

Then it started changing trajectory as if it was a high performance glider, adjusting course at 20g towards the opposite direction of wherever the nose was pointed.

Then I pointed the nose down, and it flung me up on a sub orbital trajectory 90km in altitude all the way up from 1km, and on the way back down, it briefly slowed down in the upper atmosphere (according to the speedometer atleast), before accelerating to about 1km/s as I hit the ground.

Edited June 23, 2023 by RedderThanMisty

[Davidian1024]

FWIW, I did a quick test with the Mk1 Raven cockpit.  Quickly built a super simple rocket plane to get it up to speed.  Decoupled the Raven from the rest of the craft and yes it seemed to have zero drag on it as it sailed along the runway.

I'm imagining a new challenge that could come from this.  (until they fix the bug)  Lowest orbit over Kerbin.

[Buzz313th]

Just experienced the same thing.  

Rocket config was from top to bottom..  Small nose chute, Mk1 Pod, Sm Decoupler, smallest sm ML tank, engine plate, spark engine, sm decoupler, largest sm ML tank, sm sustainer engine.

Launched to low kerbin orbit AP=80k Pe = 40km.  

Staged to pod only.

Waited for Pe@40k

When at 40k and below bare pod in... 

1) retrograde experiences almost zero drag/deceleration as velocity barely slows.

2) Prograde experiences drag/deceleration as expected.

3) Any attitude with nose perpendicular to prograde experiences the most drag/deceleration as expected.

4) at about 30km altitude, in retrograde attitude, chute deployed and didn't help to slow the pod.  Pod maintained ~ 2000ms until chute broke off at ~ 15-20km.  

5) attempted to yaw 90 degrees to try and decelerate pod...    Upon reaching 90 degrees to prograde, trajectory changed and raised AP and put the pod into an elliptical orbit greater than 90km AP.  

 

Summary: Mk1 pod is lacking any drag simulation when in upper kerbin atmosphere while retrograde.   Pod exhibits hugely unrealistic and exaggerated aerodynamic force when in upper Kerbin atmosphere and attitude is perpendicular to prograde.   

Game is still hugely FUBAR and the most basic, fundamental physics necessary are non existent or completely screwed up.    

[MechBFP]

I experienced similar behavior myself, the command pod starts to act like a space plane.

[Dakota]

Are you all using crafts made in v0.1.2.0? Or are you still experiencing this issue with new crafts?

[RedderThanMisty]

14 minutes ago, Dakota said:

Are you all using crafts made in v0.1.2.0? Or are you still experiencing this issue with new crafts?

I encountered the bug on all three of the flights I've attempted in this update. Each were new vehicles made in a new campaign after installing 0.1.3.0

I hope this makes it to a hotfix instead of the new extended update cycle, bc it looks to be a pretty game-breaking regression.

Edited June 22, 2023 by RedderThanMisty

[The Aziz]

12 minutes ago, Dakota said:

Are you all using crafts made in v0.1.2.0? Or are you still experiencing this issue with new crafts?

Nope, fresh vehicle. Fresh save in fact.

Somehow feels like the fixes done to drag went overboard and now it's barely affecting some parts whatsoever.

[RalphKerman]

24 minutes ago, Dakota said:

Are you all using crafts made in v0.1.2.0? Or are you still experiencing this issue with new crafts?

I have started with 3 completely new save files for my tests today and I am getting this "no drag" bug in all craft I created there from scratch.

I watched the video of "The Aziz" who started this topic and my pods behaved exactly like that. Falling down with almost no drag and close to surface getting picked up by some strange force and thrown back into orbit like a leaf being picked up by a huge gust of wind. This physics interaction is really strange.

[MechBFP]

1 hour ago, Dakota said:

Are you all using crafts made in v0.1.2.0? Or are you still experiencing this issue with new crafts?

In my case I was using the built in stock vehicles.

However I also tried making a new one from scratch and no difference.

[mucco]

I have had the same issue. Periapsis and Apoapsis were changing too slowly during atmospheric descent. I would bet that this is related to the hollow decouplers newest fix.

[Dakota]

We're investigating this issue internally. Will reply back if I hear anything or if the team requests more information. Thanks for the reports y'all!

Edit: heard back instantly, we'd working on reproducing this and would appreciate save and craft files if you have them.

[The Aziz]

I think it may be related because... I slapped together a plane, easy design, took me to the poles a few times in earlier versions. Aside from not being able to takeoff at all, until the end of the runway when the terrain dropped down, it worked flawlessly. In fact, so flawlessly that it kept going in a straight line 1/3 way around Kerbin (that's how much fuel it had) even after losing a wing due to a hard maneuver:

Like if the aerodynamics weren't affecting the craft, any craft. And it fell into water at 100m/s without a scratch.

Then tried the same with a larger capsule, similar result, 2km above surface it started going back up for a bit. No craft files at the moment, sorry, just testing all possibilities.

[MITCHAH]

To add to this, I am finding that, with SAS turned off,  the Mk1-3 Gumball will start to gain lift during reentry. 

To reproduce,
1. Launch a rocket high enough to clear the atmosphere
2. Decouple so the only remaining part is the Mk1-3 Gumball
3. Disable SAS
4. Allow the Gumball to fall back towards Kerbin

The Gumball, after either gaining enough velocity or perhaps hitting thick enough atmosphere, will begin to tilt and accelerate tangentially to Kerbin (that is, parallel to the ground), and after a few moments, the acceleration vector will start to point back towards space.

[MechBFP]

4 hours ago, Dakota said:

Edit: heard back instantly, we'd working on reproducing this and would appreciate save and craft files if you have them.

Brand new save using the Stock Kerbal K-2. 
Go sub orbital, detach everything but the command pod and watch what happens during re-entry. 
Considering how easy this is to reproduce they can’t seriously be having troubles finding it, that would be embarrassing. 

[linuxgurugamer]

I can confirm this using only a Tincan and a heat shield (I know the heat shield doesn't do anything)

[Davidian1024]

FWIW, the TR-3 Bulldog doesn't seem to be affected by this issue.  Currently re-entering Kerbin's atmosphere in nothing but that pod, and it's aerobraking very well.

[The Aziz]

3 hours ago, MechBFP said:

Considering how easy this is to reproduce they can’t seriously be having troubles finding it, that would be embarrassing. 

I'm only staggered that this didn't come out during playtesting

[KC3]

Reported Version: v0.1.3 (latest) | Mods: none | Can replicate without mods? Yes 
OS: Windows 11 Pro | CPU: i9-13900K | GPU: RTX 4090 | RAM: 32 GB

 

Just downloaded 0.1.3.0. I built a test rocket just to orbit Kerbin and return. All was great (moar FPS!) until my pod (Gumball) was in the atmosphere over the desert on the continent to the west of KSC. The pod just inverted and started rising from 15,000 m up to around 20,000 m. It then began to coast down again to a very hard lithobrake. I've never seen this before.

 

 

Edited June 23, 2023 by Anth12

[dsplaisted]

Same but, the Cockatoo does have drag jus very little drag so it's almost unnoticeable. 

[Buzz313th]

Fresh vehicle from a new campaign.

After installing 0.1.3, it took me less than 10 minutes to find this bug.  How did your Q&A team miss this?

[Davidian1024]

Wow, utilizing this bug I just "skipped" off of Kerbin's atmosphere.

Was coming in from a high apoapsis.  Something like 6Mm.  Periapsis was around 8km just before entering the atmosphere.  When I got down to around 5km I started going up.  As in my trajectory seemed to be getting deflected away from Kerbin rapidly.

I'm finding that I can't create a save that captures the issue.  So, saving/loading might be an awkward workaround.  I saved the game just before entering the atmosphere so I could try to reproduce the effect.  After loading the save, the above atmosphere skipping did not happen.  Everything seemed to behave normally.  I came in very fast and my AP and PE both dropped the way I would expect and I crashed into the ocean.

Here's a craft I created specifically for setting up this scenario: Mk1 Lack of Drag Demonstrator

After launch I started a very hard gravity turn once the craft had gotten to about 60m/s.  I simply set SAS to prograde relative to orbit once I reached that speed.  Just before the clydesdale ran out of fuel I switched to surface prograde until I was out of the atmosphere.  I did not decouple the clydesdale until after I was fully out of the atmosphere.  Then once I reached the AP I used the cornet section to raise my PE to around 8km.  Then I set the impulse of the decoupler to 2kN to prevent the decoupling from changing my PE too much.  Then I timewarped until I was just above the atmosphere.  Just before entering the atmosphere I set SAS to surface retrograde.  I had to adjust the authority limiter on the Mk1 to 20% because SAS seems wonky right now.  I think that might be another bug.

[mucco]

3 hours ago, Buzz313th said:

Fresh vehicle from a new campaign.

After installing 0.1.3, it took me less than 10 minutes to find this bug.  How did your Q&A team miss this?

I am at a total loss as well. How could it happen that such a basic test case is missed after an aero rework? I could picture it if nothing about aero or landing was touched, but...