Jump to content

Invisible wall in Kerbin Atmosphere 3

Recommended Posts

Trying to send a rover to Mun, I always encounter unexpected behaviour in the Kerbin third level of atmosphere.

In the first level of atmosphere, no issue:



In the second level of atmosphere, no issue:



In the early third level of atmosphere, no issue:


In the mid 3rd level, explosion with no log or any kind of information: the rupture is happening everywhere at the same time with no info log at all:



It definitely looks like a bug in the game, like an invisible wall, or:

- atmosphere 3 should be divided into 2 different atmospheres

- log regarding the vessel breaking origin should be displayed, indicating where the first rupture happens (as of now, the explosion is so massive no log is available at all)


Link to comment
Share on other sites

I'm getting the same issue. It occurs between 21.5 km for me on ascent regardless of TWR, vessel attitude or if I'm flying manually or with SAS on. Sometimes the vessel is destroyed but every time, I notice a "jump" once the vessel reaches 21.5 km (notice the vapor trails in the picture below).

Ascent, just before the jump. I'm not inputting any controls other than using SAS to hold the attitude pointed straight up.



Just after the jump, I didn't touch any controls and notice the vapor trails coming off the fins. 



Same thing happened on a different rocket at the same point. I tried removing parts from this rocket to see if I could isolate the issue and eventually I was able to get it to launch without destroying itself, but it would still "jump" at the same point. I then added the parts back until I got to the original design. I was able to get it into orbit without issue but the "jump" in the atmosphere still happens at 21.5 km.



  • KSP Version -
  • Operating System and version  (Windows 10, Windows 11) - Windows 11, version 22H2
  • CPU and GPU models, any other system information which could be relevant - Intel I9-12900ks, Nvidia RTX 4090
  • Description of the bug.  
    • Expected Behavior - Vehicle launches smoothly through the atmosphere
    • Observed Behavior - Vehicle "jumps" passing through 21.5 km, sometimes causing it to lose structural integrity
  • Steps to Replicate
    • Launch a rocket
    • Ascend through 21.5 km
  • Fixes / Workarounds (if known..)
    • I kept messing with removing/adding parts until the vessel was able to survive the 21.5 km transition
  • A list of ALL mods.  If the list is long, please consider using a spoiler window.
    • SpaceWarp Mod Manager
    • Interplanetary Calculator
    • StageInfo
  • Other Notes / Screenshots / Log Files (if possible..)
    • See above
Link to comment
Share on other sites

As a thought, could this be connected to when the velocity indicator flips from 'Surface' to 'Orbit'?

I know KSP1 did this automatically around 35km altitude, which could cause the ship to change attitude rather quickly.

...  Just checked and KSP2  seens to do it at 36km too.  So it's probably not related to that.

Link to comment
Share on other sites

Posted (edited)

I have continued the testing:

- it happens when any type of wheels is attached to the rocket - removing the wheels removes the issue

- it happens starting at mid atmosphere 3, creating regular bump of the wheels with no evident physical reasons, usually leading to the vessel getting wrecked or at minimum becoming incontrollable

- it is independent of the speed

- it is independent of the acceleration, meaning that it happens even with no engine on

- it is independent of the weight/shape: stacking multiple other parts instead of wheels do not reproduce the issue

- it is independent of covering the rover or not: having just the rover stacked at the rocket top, or protected by a cargo bay, does not change the behaviour

As a conclusion, I will check video of people who succeeds in launching rovers, because anything with wheels in my testing will never properly leaves kerbin atmosphere :)

Edited by YoD
Link to comment
Share on other sites

Look for physicless parts. There is a bug where if a physicless part is attached to a physicless part the craft will explode at just over 20000m

I wouldn't trust any smaller parts that might be physicless parts unless they are radially attached directly to the side of a craft like a fuel tank or capsule either.

If you don't know what a physicless part is google KSP physicless parts and it will take you to the KSP wiki.

My rovers work without any issues when it comes to launching from KSC.

Link to comment
Share on other sites

  • Create New...