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I have personally experienced this in Version 0.25 as I sent up my own ISS. (International Space Station)

I had a very long main payload which every other part would dock to.
As I got it into orbit and attached my first addition (crew quarters), the station started to wobble. And not like jiggle just a little to annoy me, I mean, it wobbled to the point where the docking ports collided inside of each other at the same time as the quarters clipped the fuel tanks causing the whole thing to blow itself up.

I already use struts which tremendously help the main payload stop from wobbling, but additions cause it to blow itself up.

Is there a weight or length limit for how much a ship can endure before it wobbles to death?

  • Do you have SAS enabled, maybe even with RCS? It usually works well on a rigid ship, but as soon as you have a slight instability, it can end up amplifying it accidentally. – Philipp Nov 21 '14 at 9:18
  • @Philipp Ohhhh yeah. Thats the funny part. With both enabled, it literally burns 10 Monopropellant a second trying to save itself from the disaster. It actually makes it worse due to the fact that by the time it's slowed itself from going one way, it just helped itself by flying the other way even faster. – user92092 Nov 21 '14 at 9:19
  • SAS and RCS can actually amplify oscillations on a space station instead of dampening them. There's a whole bunch of math that goes into explaining why this happens, but suffice it to say the control systems aren't smart enough to do that for the system as a whole, and the game isn't set up do perform local dampening, which is what would actually be desirable. – MBraedley Nov 22 '14 at 17:11
  • I know... I literally can't even go NEAR the ship. I can't speed up time due to rotation either so I just leave it there and switch to something else... – user92092 Nov 22 '14 at 23:03
  • Are you using HyperEdit? – Pedro Werneck Nov 24 '14 at 12:18
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The simple answer to your question is there isn't a limit to the length or weight a vessel can be. The limiting factor is stability.

It sounds like your ship simply isn't stable enough. A normal player will find the limits of structural integrity pretty quickly is KSP hence the popular saying "Moar Struts!!!" In your case that sounds like the answer.

Moar Struts

You'll find a sausage ship very unstable but you can improve stability with girders (or i-beams) and struts like this:

Stabilise with struts

It's not pretty, but it does the job.

Here's how things can get even easier: Strut in orbit - no not the moonwalk - building the struts onto the ship while in space. How? Try Kerbal Attachment System mod.

Better Struts

The link escapes me right now, but there is a mod call Quantum Struts which, by pure magic, struts your docking ports together to make them even stronger. This will help.

Last resort

Like MBraedley said in the comments, RCS and Reaction Control Wheels will make your station more unstable. Turn them off ASAP. Or experiment with them in different places, I have an inkling that positioning them centrally will make the station more stable.

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  • Yes, i've heard of all these mods, but I tend to like vanilla, no mods... BUT, if I update when 0.26 comes out (which renders the mods un-usable), does it stuff up my save or just remove mod parts from everything? eg. I have a ship with Quantum Struts and update, does it remove the entire ship or my save? Or just the custom struts? – user92092 Nov 25 '14 at 4:43
  • @FinnRayment I was under the impression the next version was 0.28 or 0.9. I prefer vanilla as well and the only option there is make your station smaller or different shapes (eg star). FME mods normally work after upgrades or the upgraded mods are available soon after the game update. Worst case scenario, you might lose the station or the save may not be playable - thats the risk involved in playing a BETA. I've had 6 different games from different versions. – Coomie Nov 25 '14 at 6:02
  • Ok thanks, and one last thing, WHY was it actually wobbling? Answer this and i'll accept. Cheers. – user92092 Nov 25 '14 at 6:18
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    @FinnRayment KSP processes the physics for each piece of the station, not the whole station as a single unit. So if forces (eg. rotation) are applied to one end the will travel along the station pushing each part in a wave. If you have reaction wheels (or RCS) on two ends movement will happen at both ends and ripple done the ship, back and forth and that's the oscillating that you're seeing. – Coomie Nov 25 '14 at 7:42
  • You know what? That ACTUALLY makes perfect sense. You've earned my appreciation. Cheers. @Coomie – user92092 Nov 25 '14 at 9:50
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I have had a similar problem in early game moon missions.

Try adding as many static fins as you can and be sure to keep away from the time warp button

Even some of my small craft would survive the flight but if i hit the time warp all hell breaks loose.

Here is an idea - Please backup your files before you go editing CFG's

In general all configuration files required for this are in a subdirectory of GameData. Itself is a subdirectory of the root directory.

When you find the folder GameData, open it

From here you will find two other folders. The "NASAmission" folder, and the "Squad" folder.

You may see more folders if you install mods for KSP. The "NASAmission" folder contains all the parts created with the help of NASA in the most recent update, like the four block engine, or the Launch Escape System. The "Squad" folder contains most of the stock parts, like the Command Pod Mk1, or the Mobile Processing Lab. go ahead and open the "Squad" folder.

From here, you will find the folders containing just about every object in the game. Since you are editing parts, open the "Parts" folder (obviously). There is also a "SPP" directory which contain the parts from the Spaceplane+ mod integrated in 0.25. From there, you will find more folders, each one representing a tab in the Vehicle Assembly Building

So now you will need to look at your crash details (what fails first) and find that part's folder, inside that folder you will see partname.cfg

open it up in a text editor - notepad or whatever

and do a search for "Standard part parameters tab"

What you are looking for is the breakingForce parameter.

I am at work right now so i cant test if you will even find it in there as i only ever play with my crashTolerance but all the parameters should be in there. I do know however that if you do find it it may be set to 1.0 which seems to directly scale to 50 Kilonewtons of force.

.yea science.

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  • I've tried that too. It seems to be the physics engine at this stage. I was just wondering how far you can go before 'hell breaks loose' – user92092 Nov 21 '14 at 9:37
  • Edited with an idea – anthonytherockjohnson Nov 21 '14 at 10:04
  • Would there be anything I could find in there related to the actual reason WHY it is wobbling though? It's going to take some time anyway sending the thing which is going to weigh a ton and be very long successfully to space in the first place! – user92092 Nov 21 '14 at 10:20
  • The why - I cannot answer without the actual saved ship loaded in my KSP and even then you may be on to a load bearing bug in the engine as you said before - CFG tweaks will fix it but we would need to know exactly where to look – anthonytherockjohnson Nov 21 '14 at 10:23
  • I'm sorry, I don't understand a word you just wrote? – user92092 Nov 21 '14 at 10:23

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