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Bouncing Lander on the Mun

Frida Space


Hi, I hadn't played KSP for more than a year before I decided to pick it up again yesterday. Today I decided to send a very small lander to the Mun. I managed to land it very smoothly (at like 1 m/s). As soon as I landed, the landing legs compressed and then extended like a spring. Since then, the lander keeps bouncing, reaching less than one metre in the air and then falling back down. As it touches the ground, there is an instant in which it is basically still, allowing me to time warp. However, as soon as I go back to real time, the bouncing continues. If I exit the game and reload the craft, it shoots up a lot higher and then goes back to bouncing. Does anyone know how I can solve this issue? Thank you very much!


Edit: here's a gif of the issue: https://imgur.com/a/XETJPJX (I am struggling to embed it into this post, sorry)

Edited by Frida Space
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1: Minimize spring and dampening. Spring should be lower then dampening, dampening slightly higher. If problem still persists you should drag these values down as close to zero.
2: This option works regardless, but, should be used also if method 1 doesn't work. Which is, use tinier landing legs! :wink:I see you already have these.
3: Use 3 legs instead of 4. A craft only requires 3 legs to stand upright. Also saves you weight from the launchpad while making the entirety a flea length more efficient.

So what if you just changed to 3 legs, lowered spring and dampening, then what do you do?

A: You might feel that the other tiny rover wheels or landing gear parts can substitute landing legs like the ones you got currently installed. Your decision...
B: Use other parts like cubic octagonal strut or smallest wing segments to use as stationary legs to substitute the actual ones.

The problem with KSP is that the part on terrain collision effects are not that optimized to simulate the proper physical interactions one might expect. Bugs like this will appear.
Even the parameters like spring and dampening are arbitrary but do work. In a way, lowering both dampening and spring creates the same effect to deter bounciness as if you were installing a smaller leg which has lower spring and dampening by default while it's spring and dampening can be lowered also.
The effect of spring and dampening on the terrain is in some way calculated on the spring, dampener and I suppose a few other factors relative to the weight of the vessel it carries.

So the lighter the craft the less legs, the tinier the legs and the least spring and dampening should be applied. There comes a point where the least legs, the tiniest one and the absolute 0 spring and dampening setting doesn't work. In that case you need smaller landing legs or the tweakscale mod to scale it down.

edit: I might have improperly watches the .gif

But is the vessel moving with the surface as the legs retract and extend or is the rest of the vessel still while the legs move in and out? Are the ends of the legs touching the terrain? Or do they retract away from the surface and then lower down again.
It's not clear to me on the gif where the surface is because of you graphics settings. In a way it seems it itself is completely still and only the landing leg animation plays.

In which case it's still useful if you even cared for it but then what I wrote isn't very helpful as this then is something else.


Edited by Aeroboi
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I just had the same thing happen to me. I landed quite gingerly on the Mun but my tiny lander probe started to bounce up and down. I don't see any damper and spring controls in the landing leg menu so I can't play with that. Is this only in the VAB? I'll look again.

I got it to stop bounding by retracting the legs. It is now sitting on its nearly spent fuel tank. I'm using those tiny side rockets, luckily.

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I have a rover on Minmus that has this same problem: when I switch to it, the rover begins bouncing up and down (FYI his particular rover is full of liquid fuel and oxidizer, so it has a substantial amount of mass). When controlling a nearby lander, the rover continues to bounce and will even resume bouncing after time warp while it is not being controlled.

It didn't have this problem until either 1.4.4 or 1.4.5, so I'm wondering if this might be the result of a new bug. This rover was already on the surface since 1.3.1 and never "bounced" before so I know it's not a design or construction issue. The rover is on four Rovemax M1 wheels, so when it's bouncing it looks like an El Camino on hydraulics.

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