Docking at a rotating space station

[Talonsin]

I setup a station in Mun orbit and added a few different sections with docking ports on the side. The dang thing rotates a bit and I can not line up to dock fast enough to catch one of the ports. I even tried Mechjeb but after 2 hours and almost 2000 monop, it was also unsuccessful. I changed to station control and from there it does not seem to be rotating. Anyone have any advice? I would hate to have to make a giant spear in space as my next station but that's my only other option if I cant figure out this rotating issue.

Thanks

[MrKicker]

sometimes large craft like to rotate for no reason whatsoever.

However, timewarp cancels all rotation.

[Tripzter]

Indeed click time warp from time to time to get the uncontrolled station to stop turning.

[Tiron]

Indeed click time warp from time to time to get the uncontrolled station to stop turning.

This is because going into timewarp puts all ships in the active scene 'on rails', which halts all movement. Just blip it up to 5x for a second, it'll stop rotating.

Part of what's going on is that the SAS has a tendency to overcorrect, especially the Old SAS, which by default Mechjeb's autosteering is pretty similar to. So what happens is, you get it stable, but really it's wobbling back and forth slightly. When you switch craft, it stops being controlled, and whatever the last overcorrection was, that's how it moves.

You might try using the default SAS to stop it instead of Mechjeb as well, as it's a lot less overcorrect-y, even if it does have some issues.

[bayboy]

You are probably trying to dock with the docking axis along the prograde/retrograde vector, or the radial vector. As the two vessels orbit, their relative position to each other changes. E.g. if one is "on top" of the other, after 90 degrees of orbital rotation, they will be "side by side", when viewed from above. But if you align them "north-south" before docking, they stay in that position throughout orbit. I think.

[Janggoth]

I know this isn't the same as what you're asking help for, but I jsut got reminded of this... The station was rotating for the artificial gravity so the shuttle rotated at the same rate before moving in.

[King Arthur]

I've noticed that the Mun is excessively prone to rounding errors and phantom forces on objects in its orbit for some odd and as-of-yet unknown reasons, stations spontaenously spinning at the Mun aren't an unusual occurence at least from my experience. Here's what I suggest you to do mitigate it:

1. Turn SAS on after orienting your station.

2. Dock quickly but safely, you don't want to take time with docking here lest the station starts spinning again.

[Scorpi15]

At the mun crafts spin in relation to the ground much more then if they were in orbit around kerbin, because the Mun is smaller. and so the surface slopes away faster, even though the ship is still at the same orientation. It's the same reason ships drift from the prograde vector around Kerbin. It just happens faster around the Mun.

[Amoun]

Personally, never had a rotating station docking problem (not yet?). Just like others have said, I wanted to confirm the timewarp. I do that to cancel any rotation I encounter. Works amazing, especially if you are getting frustrated with a wobbly ships' orientation.

[Bean]

I find the new SAS works brilliantly for keeping a ship aligned, though you should try a North/South alignment to minimize the runaway you get with an orbit.

[Psycix]

If the problem is that the navball (so actually the mun itself) rotates under the station, have a equatorial orbit and point the docking port towards the north or south pole. This way it will only roll while staying on the same point. Your docking craft can then align along the same north-south axis and will (aside from roll) be aligned perfectly.

[King Arthur]

At the mun crafts spin in relation to the ground much more then if they were in orbit around kerbin, because the Mun is smaller. and so the surface slopes away faster, even though the ship is still at the same orientation. It's the same reason ships drift from the prograde vector around Kerbin. It just happens faster around the Mun.

I've had entire stations literally topple over from phantom forces/rounding errors before around the Mun, which is vastly different from the seeming "orbital spin" you describe that is actually quite normal.