Unintended orbital rotations, fix? Help Plz.

[Ace_Septre]

I recently started trying orbital rendezvous, but have a problem with the craft that I'm not controlling, and trying to dock with, rotating out of grade even before I get within docking distance, and the entire time during the docking process, leaving it nearly impossible to dock. Is there any way to keep orbiting craft from rotating while not under user control? I use MechJeb if that makes a difference.

[Claw]

Hi Ace,

I'm going to guess that your problem is trim. There's a weird little bug if any of your craft have out of neutral trim.

Go to each craft in physics range and press ALT+X (or MOD+X if you aren't using Windows). That will reset the trim on all the craft. Now when you get within range, try to maneuver and see if your target sits still.

Welcome to the forums!

~Claw

[Ace_Septre]

What do you mean by physics range? Just go control the craft and press Mod-X while the craft is under user control?

[Sirine]

Make sure you are not in "docking port magnet range" (about 1~2 meters between docking port). Hit F5, Then Hit F9. This should fix the rotation.

[Claw]

Oh, I'm sorry.

"Physics range" is when you get within about 2.5km of another craft. Then both craft are "simulated' by KSP's physics engine.

Yes, press Mod+X while the craft is under user control, but do it for both your docking craft AND your target craft. Once you get within range, press ] or [ to switch vessels, zero out the trim, then ] or [ to switch back.

~Claw

Perhaps this will clarify what I'm talking about: http://forum.kerbalspaceprogram.com/threads/78005-Controlling-All-Craft-in-Physics-Range

[Fyzzi]

Yeah, reseting the trim as Claw suggested should deffinately solve the problem, but since nobody else suggested it - you should switch to the spinning craft and press T to apply SAS... that will remain switched on even after you switch back to your previous craft...

[Mesons]

I suspect that the issue you are running into is the orientation of East and West changes as you orbit the planet. A little workaround that I thought was suggested in the docking tutorials here (but I now can't seem to find) was to align the uncontrolled ship's docking port to either North or South. The North/South axis is the axis the East/West/Up/Down plane rotates around, so the ship will remain facing the way you pointed it and simply rotate around. When you go to dock with it, just point the controlled craft toward the other direction and voila, alignment achieved.