Station in orbit around Kerbin under acceleration for no reason

[marce]

Today at Fun-with-bugs: whatever I put in orbit around Kerbin accelerates forever at about 0.4G

Without any reason to do that.

Note: this is not a support request, it's just for your entertainment.

Edited January 5, 2015 by Vanamonde

[LethalDose]

Just curious: did that station have a claw attached to it at some point? I've had stations and vessels behave similarly and I can usually trace it back to cla exposure.

Not trying to solve your problem cause you said it's not a support request; just my own curiosity.

[Scotius]

Physics engine does strange things if there are parts clipping into each other. It leads to ghost forces affecting your ship. It is possible you've accidentally stumbled upon iteration of (in)famous Kraken Drive.

[marce]

Just curious: did that station have a claw attached to it at some point? I've had stations and vessels behave similarly and I can usually trace it back to cla exposure.

Not trying to solve your problem cause you said it's not a support request; just my own curiosity.

No claws

Physics engine does strange things if there are parts clipping into each other. It leads to ghost forces affecting your ship. It is possible you've accidentally stumbled upon iteration of (in)famous Kraken Drive.

It really is a Kerbin only problem. Something in Mun orbit is safe, but once it has been in kerbin orbit and reloaded once there it will accelerate.

I also tried parking in Mun orbit, then bringing it to kerbin orbit - still works.

I have a Jeb at 0.05c on his way to another system by now

Certainly a kraken drive, but I can't steer it so it's only 10% the fun.

[tater]

I had a flag do this. I switched to it with the ] key and it fell through the Mun and would not let be switch to anything else because it was accelerating.

[MalfunctionM1Ke]

Looks like you have some phantom forces accelerating your spacecraft forwards. In the video it was a somewhat radial- acceleration that lowered your periapsis and raised your apoapsis.

I also have no clue whats going on there but phantom forces sometimes originate from clipped parts or models of parts that are sticking inside each other.

The Krakendrive is an abusive mechanism of this:

Edited January 4, 2015 by MalfunctionM1Ke

[problemecium]

I may as well chime in. My hypothesis is that the station's root part is a non-physics part, so for mysterious reasons the physics engine is getting all confused about it. I had this happen to me a couple times when I made the structural fuselage (which I thus discovered was non-physics) the root of my fake asteroid and when I tried to switch to an octagonal strut I'd ditched in Munar orbit.

[King Arthur]

I had this happen to me a couple times when I made the structural fuselage (which I thus discovered was non-physics) the root of my fake asteroid

The Structural Fuselage is not a physicsless part.

[marce]

Moved to support, presumably un-modded.

No it's heavily modded (I'm surprised every time that there seems to be still a single stock player out there ).

As I said, this was no support request, please close the thread to avoid further confusion.

[NecroBones]

Phantom acceleration is a bug I've seen come up quite a few times, starting with 0.23.5, and it doesn't always need a claw to be attached. I've found that once KSP starts doing that, I need to quit out and fire KSP back up again.

That is, if I try to just revert and re-attempt the launch, it'll do it again, unless I close and re-launch the game.

I never noticed a direct cause, though it seems to happen more frequently if the game has been running a long while, or I've changed focus to different vehicles several times.

[problemecium]

The Structural Fuselage is not a physicsless part.

It must have been in some version I played... whichever one first introduced asteroids, I think (0.21?). If I simply made the root part something else, like a fuel tank, the problem disappeared.