Kerbal Space Program

Not sure what is going on here. The attached craft file differs from the vessel in your screenshots slightly, it has additional boosters on the side. It causes KSP to crash to desktop when the first staging event is activated. Every time.

Ok, so, i tested this. One ghost stage occurs, because the boosters are mounted on radial decouplers. Those decouplers are in their own stage, that never gets activated, and if you seperate the boosters together with the bottom core stage, they don´t show up anymore.
The other problems seem to be related to bug #2355, which leeds to a CTD on linux and mac os, but not on windows. However, it still creates a stackoverflow.

Kosmognome, can you test if the problem is solved by deleting "PhysicsSignificance = 1" from GameData/Squad/Parts/Structural/Size3Decoupler/part.cfg as suggested in bug #2355?

rudi1291 wrote:

Kosmognome, can you test if the problem is solved by deleting "PhysicsSignificance = 1" from GameData/Squad/Parts/Structural/Size3Decoupler/part.cfg as suggested in bug #2355?

Ok, so I've tested this. Editing the part.cfg that way removes the ghost stages from the last attached vessel. The problem with camera moving away and the spinning out of control is still present, thorugh. This seems to suggest that the ghost stages are not all responsible for the problem (albeit still annoying).

The reports in #5198 and #5216 have very clear and simple reproduction steps.

Are you sure that this issue should have "critical" priority? Are you really sure about that?

Due to how Unity joint strength works, a compromise had to be met with the TR-38D. This generally works, but we have found that adding struts can have an adverse effect as seen in #5198. It is hoped that joint strength will increase as a result of changes in how Unity works which would obviate the current situation. The TR-38D doesn't like being staged at the same time as an engine, and will be seen to stick. This stickiness, combined with struts leaves the staging in an indeterminate state (the engine and decoupler have detached, but the struts remain connected) which has the effect of shifting the CoM and consequential loss of control. This situation is also shown in the staging column where the bottom icon is empty.

The workaround for this situation, and probably all others that involve this decoupler, is to stage them separately. Simply move all TR-38D decouplers to a stage preceding the next stage engine. Staging then becomes a 3 phase affair.

1. Current engine decouples from the decoupler.
2. Decoupler detaches from next stage engine.
3. New stage engine fires.

Any struts will then automatically attach to the nearest part (the part being jettisoned) and not the useful part of the craft.

I have tested your craft using the above, and can see no further issues. Please report back if you also have success.

bv1 wrote:

Are you sure that this issue should have "critical" priority? Are you really sure about that?

It not for me to decide, but an issue that crashes the game on 2/3s of the plattform that can be triggered by normal gameplay easily by just using a stock part should imho be more then low priority (or am I the only one who uses 3.75m parts?!). There is at first the NullReferenceException in the editor that seems to be surpressed by the game which indicates a significant problem with how he game handles the data model, and may even be connected to the later stackoverflow error in flight (in fact, i think it is very likely connected).

I have tested your craft using the above, and can see no further issues. Please report back if you also have success.

Yes and no. Change the staging so that the decoupler directly above the Cargo bay and the rokomax decoupler above that are on separate stages. Fly straight up until fuel is burn out of the stages below the cargo hold. Use the decoupler. Normally, you would now use RCS to move a bit away from the cargo bay, turn the CSM around, and use the Rokomax decoupler to jettison the 3.75 to 2.5 adapter. However, after using the 3.75 decoupler above the cargo bay, the CoM again is completely wrong. activate RCS and press 'H' and the ship will move out of the camera focus and will leave the screen to the top again. In that case, the decoupler is on it's own stage, but still exhibits very strange behavior.

I'll upload some screenshots and craft files later on.

Hallo Squelch,
this seems to work, thank you very much.

However, it kind of unsatisfying to have to drop the decouplers that way. It doesn't look good, it creates a very excessive amount of stages and it is very inconvenient to work with. basically every craft that uses 3.75 decouplers has to be designed around their bugs, and has to be staged around their bugs. You can't just build a rocket and it works. And I'm still not sure if I understand how I would need to stage and build another vessel with 3.75m decouplers so that I don't run into the same problem again.

Tip: Open the lower bay doors, disable crossflow on the payload decoupler, and button up again before launch. This ensures the fuel isn't robbed during ascent.

I've replaced that with a rokomax decoupler, works much better and makes extracting the LM also a smoother process.

Anyways, thanks for your time and patience ;)