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Phantom Acceleration and Unstable Orbit


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Whenever i launch a new craft everything goes fine and i reach my destination without any problems. The problem starts when i return back to KSC then switch back to the craft only to find ap and pe constantly moving. Any other craft i have in orbit are experiencing the same issue. They are stable unless i switch to them. When the physics starts effecting the craft orbit constantly moves. It is stable while fast forwarding tho so only when physics are applied that this issue starts. The fact that the game is letting me fast forward might mean that this is not phantom acceleration since if i was accelerating the game wouldn't let me fast forward. Not only the pe and ap constantly moves the inclanation changes when i turn the craft and comes back into its normal place when it returns back to the first position it stared the turn.

Mods: WaypointManager, MechJeb2, [x] Science!

Removing the mods doesn't fix the bug and new game i create doesn't have this bug. So i am experiencing this only on my main career save. Also tried removing every craft there is and the problem still persists with the new craft i send into orbit. Career started at 1.0 and moved to 1.01 and 1.02. Reinstalling the game doesn't help either same bug keeps happening only to the career save.

Is there a way to fix this or save the career file?

Edited by n0xiety
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Is your eccentricity really, really close to 0? IE did you use MechJeb's circularize? Because if that gets too close to 0 you get errors in calculating apoapsis and periapsis, if it's actually 0 they cease to exist. Basically the game has limited precision, and the change in altitude over a range is too small, so the apsides get smeared along the orbit and start jumping around randomly. It shouldn't really harm anything, but if it's too annoying you can de-circularize the orbit slightly.

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i know what you are talking about but this is not that. The apoapsis and periapsis are literally changing in big numbers and the inclanation is moving. This is happening to all of my flights even those that were stable before becomes unstable once i switch to them. So there seems to be a general problem with the forces and i have no idea how to fix it.

Oh here is an aditional info. This seems to started after using a claw on an E class asteroid and trying to push it. After that i didn't gave it much tought and kept playing eventho the asteroid became unstable. And the funny thing is i didn't even notice the bug because it is not happening to newly launched crafts as long as you stay with the craft and not return to KSC or switch to another craft. I generally finish my missions in one go so i didn't even notice it untill i wanted to build a space station which was atleast 20 saves later.... After that checked my sattelite probes from ages ago and they had the same problem... Now i don't want to return to 20 saves ago to fix this...

Edited by n0xiety
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Maybe deleting the asteroid?

As i said in my first post i deleted everything but the problem effects new craft even after deletion of every craft and asteroid there is so something about physics must have just snapped. There must be a fix for this maybe something like editing the save file itself but i don't know what to edit.

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I experienced the same problem twice, each time was on a space station (one around Kerbin, one around the Mun).

I have completely different mods, none of those you mentioned. Orbits were more or less circular, excentricity was very low (between 0.001 and 0.003). On both cases I was doing some maintenance work on EVA with the KIS mod. After reloading the game, it disappeared and I failed to reproduce it, I'm still trying to understand it. Next time I'll alt-f12 and see what's causing this Keplerian Kraken.

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Yeah i don't think its from the mods since i removed everything, reinstalled and ran the save in stock ksp but the problem still persists. Hope it dissapears for me too but no luck there yet.

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I had the bug today again. It's out there since I'm playing KSP (0.24?!?). It occures everytime when a dockingport is radially attached to a tank, hitchhiker or sciencelab. Even a radial attachement point doesn't help. In mun orbit I've recognized phantom torque before 1.0.

Because I haven't found a solution to this, I'm using dockingports attached to nodes only. If it's the same in stock, perhaps it should be moved to unmodded installs.

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I edited this post because I did not re-read your initial post before making it. As such I was ignorant and offensive and suggested stuff you had already tried.

For this I apologise. I hate it when people don't read through my threads before making a comment and I was guilty of doing just that.

All I can add is that it sounds like your persistent file is corrupted. What you do about that depends largely on your patience and fortitude.

Edited by Daveroski
Because I was an ignorant fool.
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I edited this post because I did not re-read your initial post before making it. As such I was ignorant and offensive and suggested stuff you had already tried.

For this I apologise. I hate it when people don't read through my threads before making a comment and I was guilty of doing just that.

Don't worry about it. After 2 days of trial and error finally managed to fix the bug by merging a new game persistance file and the career persistance file after opening the game in stock ksp. Cost me all my crafts and i only took whats important like science done in bodies, money or my kerbals with their experience and missions. Still im glad to be able to continue playing the same career. Would hate to loose my kerbals. Bases can always be rebuild and i have .craft files anyways. Worst case i could hyperedit what i once had.

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This doesn't really seem solved as we don't know what causes the problem. I've a station around Kerbin and Mun but only experience this on my Mun station. My orbit changed drastically in about 11 hours of idling around Mun.

You are right the problem itself isn't solved but i marked it solved since i found workarounds and preventions that reduces the chances of it happening again.

It was a general problem for me since i experienced it in all of my craft. I think this is caused by either ships that are too big and not sturdy enough ending up bending and creating kraken forces or moving something big with a claw. Clipping parts together is another reason why this happens but only if the parts are under alot of stress. Well i kinda learned my lesson and using KAS mod with ubizor welding mod works stable enough for me atleast for now.

It is true that this shouldn't happen at all and one craft somehow effecting the whole universe and breaking physics is a serious bug that should be fixed and purged from stock ksp atleast. As i see it this bug is like the oldest bug there is in KSP which they still just couldn't fix. Did they improve it? Yes. Untill you start creating big and complicated crafts the kraken stays away laying in the deep dark corners of the universe waiting for the opportunity to rise. In the end its just a matter of time.

Untill this gets fixed we as players have only one choice and that is to be really carefull about what we build and how we build them while using mods that improve structral integrity. If all else fails merging an untouched persistance file with the broken persistance file makes it so that you can atleast keep playing the career even if you loose most of your crafts.

Edited by n0xiety
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Just piggybacking on this:

I have not tried it since, but in 1.0 there was some phantom acceleration under 1000 km above Jool. Idk if it was just me or if it is fixed.

Hell i have been to jool recently and while passing at 220km for a gravity assist out of solar system my trajectory literally got bent towards jool. It looked like the periapsis still stayed at 220km but i could see my trajectory going inside jool and going out again doing a strange curve. While this is happening i couldn't even warp as it said the craft was accelerating... I think there is another thread for this particular problem and what i just described happened in 1.02 version.

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Untill this gets fixed we as players have only one choice and that is to be really carefull about what we build and how we build them while using mods that improve structral integrity.

I'm using Kerbal Joint Reinforcement mod, so I don't know how much that will help in reducing a wobble on a large station. The thing that strikes me as odd is my Kerbin station is larger and contains more parts then my mun base and does not suffer from kraken forces. I'm going to start ditching sections of my station to see which part, if any, is causing the unstable orbit to occur.

I appreciate your suggestion/solution and might have to use it as a last resort.

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  • 11 months later...

Hi there!

I also experienced this problem, but only with space stations in orbit around Kerbin and only I docked additional parts or spacecrafts to the station. Docking with satellites or grapping them did not cause the problem. Sometimes it helped to switch to KSC and back or to use MechJeb and set a new orbit (if I had docked something with engines).

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I'm having the same problem as well with stations around Kerbin. Sometimes the problem does not occur until I dock two modules together, but other times I get constant deceleration/acceleration even with Orion or Soyuz style ferries. I'm using Tantares/Contares, SDHI and Habtech (along with the necessities), although even fully stock craft have this issue for me. 

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