Complex Booster Breaking My Lander And Rover

[Hendo50]

Been playing for a while and decided it was time for the challenge of landing on Eve. I've built my lander along with a rover to take 'ole Jebs around the surface, but I've run into a problem. While testing my lander/rover combo on Kerbin, everything works great with a simple booster (i.e. one that gets me just high enough to test parachutes, etc.), but when I started doing full-up tests with the booster that'll take me to orbit, all hell broke loose.

My rover is supposed to split off the main lander, and parachute down by itself at ~4m/s. This works perfectly with a simple booster, the rover floats down at ~4m/s for a soft landing. But with the complex booster, when the rover lands, it bounces all over the place breaking itself apart.

The lander works perfectly, with the simple booster. But with the complex booster, all the lander legs explode when I touch down, sometimes taking the rest of the lander with it.

Nothing at all changed with the rover or lander - the only thing different from one test to another was the size/complexity of the booster strapped to the bottom.

I'm pulling my hair out over this one! been trying for two days to get it to work, if I can't, I'm limited to really simple designs that barely get me past Minmus... Help!

[Goody1981]

Two things to start helping

Are you running 1.4.3? Because exploding lander legs was an issue in 1.4.2

And...can we see some screenies of the craft? So we can get an idea of what you mean by simple/complex booster.

[Gargamel]

12 hours ago, Hendo50 said:

Nothing at all changed with the rover or lander - the only thing different from one test to another was the size/complexity of the booster strapped to the bottom.

Just a point of order........ You're not trying to land with the booster still attached, correct?   Just asking... cause, that would be the problem....

 

Fly your complex booster higher upon launch, get to orbit, and then try to land.  See if you are still having issues after the booster leaves physics range.  

12 hours ago, Hendo50 said:

I'm limited to really simple designs that barely get me past Minmus

This statement is getting my attention, leading me to believe there is a design issue going on here.  A simple booster or transfer stage should be able to get you about anywhere.  Simple to me means only a few parts, regardless of big they are.  The design of the booster stage should have no affect at all upon the lander stage.   The booster should not be in range at the time. 

As mentioned, pics would really help. 

[Zeiss Ikon]

Does your rover use autostrut while in boost configuration?

If so, either change the autostrut target (don't use "heaviest part"; use "grandparent" if you have to have autostrut), or disable it entirely.  Autostrut can, if there's a change in configuration that leads to potential ambiguity on what's the "heaviest part", cause escalating oscillation that will eventually separate parts at non-decoupling joints, potentially also causing explosions when those parts collide with other parts.

An example of this is in my recent "What Did You Do in KSP Today" posts concerning Minmus Station Alpha -- after I had four tank sets docked to the station, with the "heaviest part" autostrut that they needed to launch intact, every time I'd load back to the station (i.e. ease in physics by bringing the station into focus or physics range) it would start to oscillate, either to the point of disassembly and ejection of parts, or to the point of part explosions.  Turning off autostrut as quickly as possible after loading solved the problem for me.

[Hendo50]

On 5/20/2018 at 10:40 AM, Zeiss Ikon said:

Does your rover use autostrut while in boost configuration?

If so, either change the autostrut target (don't use "heaviest part"; use "grandparent" if you have to have autostrut), or disable it entirely.  Autostrut can, if there's a change in configuration that leads to potential ambiguity on what's the "heaviest part", cause escalating oscillation that will eventually separate parts at non-decoupling joints, potentially also causing explosions when those parts collide with other parts.

An example of this is in my recent "What Did You Do in KSP Today" posts concerning Minmus Station Alpha -- after I had four tank sets docked to the station, with the "heaviest part" autostrut that they needed to launch intact, every time I'd load back to the station (i.e. ease in physics by bringing the station into focus or physics range) it would start to oscillate, either to the point of disassembly and ejection of parts, or to the point of part explosions.  Turning off autostrut as quickly as possible after loading solved the problem for me.

I'm honestly not sure what "autostrut" means - I'll check out your post though and see what I can learn!

[Hendo50]

On 5/19/2018 at 4:38 AM, Gargamel said:

Just a point of order........ You're not trying to land with the booster still attached, correct?   Just asking... cause, that would be the problem....

 

Fly your complex booster higher upon launch, get to orbit, and then try to land.  See if you are still having issues after the booster leaves physics range.  

This statement is getting my attention, leading me to believe there is a design issue going on here.  A simple booster or transfer stage should be able to get you about anywhere.  Simple to me means only a few parts, regardless of big they are.  The design of the booster stage should have no affect at all upon the lander stage.   The booster should not be in range at the time.  

As mentioned, pics would really help. 

 

Nope - not trying to land on the booster stage - i've got legs and everything.

It's a bit misleading to say i can't get past Minmus - just overexageration. I was able to build Duna launch/return vehicles both in surface return configurations, and Duna-Orbital rendezvous - so both of those were pretty complex builds - both of which had rovers (though because Duna isn't as hard to return from, I was able to have my rover attached to the bottom of my lander, and just decouple it when i landed, rather than have it parachute down separately).

I'm running v. 1.4.2 - so i'll give the new version release a try - and see what that does.

 

Here are screenshots of my ship - both of the simple and complex booster (the lander portion hasn't changed - it's literally just the first/second stages that are different):

Complex Booster
https://drive.google.com/open?id=1SB7i0UaXXadJhHmL0JFhs9alQE0JCcJE

 

Simple Booster
https://drive.google.com/file/d/1D_OKdzLyArg6QbN6Z3DyKAjsQlAE6Z3i/view?usp=sharing

 

 

[klesh]

Throw them pics up on imgur, please. 

[Goody1981]

Still struggling to understand what you’re saying, but if I’m hearing you correctly - the lander section behaves differently depending on what was previously attached to it? That is very strange!

Maybe check to see if some fuel from the lander is being used by the ‘booster’ in one of the situations (to make sure this isn’t happening, disable fuel cross feed in the decoupler separating the stages).

If that isn’t the issue, then the only thing that could be the problem is that the two lander stages in the two craft are NOT the same. It may be some tiny setting you’ve clicked on some part (like an autostrut as mentioned) but if the craft were the same, they would fly the same :p

[Hendo50]

Thanks all!

As it usually is - the solution was so much simpler than it seemed - turned out it was just the version of KSP I was running.

 

The lander leg issue with 1.4.2 was causing the same issue with my rover wheels - the more complex the ship, the more physics the game had to track, and the more erratic the behavior on landing.

I updated to 1.4.3 - and now everything lands nice and smoothly, with no trouble at all!