Docking Port Woes

[Blue]

Tell me if you've been in this situation before:

Docking two very large, highly sensitive vessels so you're making a careful, slow alignment and approach, trying to do everything in the best manner possible. You float cautiously towards the target, bobbing along at 1m/s, and then the moment you've been waiting for, 2 meters to go, the docking port on both vessels is lined up perfectly, and then, no docking. The ships continue to drift towards each other, and then bonk together, deflecting away and making you suddenly fear that they've damaged. AAUUGHH

I happened to be recording at the time, so instead of screenshots I got a video of the event.

I initially suspected two things: either A. the other vessel's docking ports were damaged and therefore unseperated (undockable) debris. However, switching between vessels would indicate that.

Or, B. a part error in the save that had one of the docking ports set to a non-ready state for a buggy stupid reason. But when I checked through my save I couldn't find anything. Granted, I'm not all that good with looking through code, and I can't figure out how to get KerbalEdit to work.

Help!!

SOLUTION:

Posted by kujuman

HOW TO FIX THE DOCKING PORT

1. Go into the persistent.sfs file

2. Search for a line which says "state = Acquire"

3. Change to "state = Ready"

4. Load up the game and dock with the port nearby.

Edited December 27, 2013 by Blue

[sal_vager]

They are on the right way round, right?

[Hodo]

They are on backwards.

[Cashen]

They're either on backwards, or you didn't have the target docking port selected as target, while yours was set as 'control from here'. Sometimes KSP unselects the target in the background for whatever reason. Also the large docking ports are (somehow) easy for some people to put on backwards.

[Blackstar]

Target and "control from here" doesn't matter for docking. It certainly makes it more convenient, but ports will always dock if they're close enough.

EDIT: After closer review of the video, I *think* they're the right way around. I still don't see the window (low texture settings maybe), but the outer ring looks correct.

If the tanks are full, the magnetic force probably won't be able to move them any. You need to either be perfectly aligned, or come in even slower.

Edited December 26, 2013 by Blackstar

[Decent Weasel]

i've had similar issues with slow drifts toward docking ports. I generally just orient the ports toward each other and follow the purple nodes so I don't have to translate into position. (yes, I dock without RCS thrusters.) Since this approach requires delicacy and frequent adjustment, I have slow approaches too; my trick is to make a burn when i'm just a few meters away, so i get up enough velocity to engage the port. If you go too fast, you blow up, of course, but if you go too slow the ports don't tend to engage with each other. They need some oomph.

[brooklyn666]

Are you sure they are rotationally AND linearly aligned? It looks like they're a bit off, but it's hard to tell from the video whether that was before or after the collision.

[Murph]

Can't be sure, as there's no completely clear view of the ports, but I think they are both on the correct way around. What I think might be happening is just docking too violently. With large (either size, mass, part count, or any combination of those) stuff docking, I find it's best to more or less stop just before contact, and let the ports pull themselves together, rather than actually collide.

[jjwb22101]

Everything looks good to me. The docking ports are the right way around, and it seems to me like they're close enough to be magnetically attached. Everything else (rotational alignment, etc. )doesn't matter, so I don't have any idea why they aren't connecting. My only thought is perhaps something to do with the .23 update made some changes to docking ports. Did you build them in different versions, or try to fly them from a version different from when they were built in? Other than that, I got nothing.

[Zwer.ch]

Did you disable SAS while docking? I found recently my SAS fighting and therefore counteracting the docking ports magnetic force. Without SAS the docking ports snapped in immediately.

[Blue]

I'm not an idiot, I put the docking ports on the correct direction. You can see it in the video. The dock-side of large docking ports is bevelled at the edges, the wrong side is flat.

I also set the target as the docking port-- which you can tell since in the video the purple reticle is aimed towards the orange tank (which is radially mounted) rather than the probe body (which is in the core of the other vehicle).

Everything looks good to me. The docking ports are the right way around, and it seems to me like they're close enough to be magnetically attached. Everything else (rotational alignment, etc. )doesn't matter, so I don't have any idea why they aren't connecting. My only thought is perhaps something to do with the .23 update made some changes to docking ports. Did you build them in different versions, or try to fly them from a version different from when they were built in? Other than that, I got nothing.

The large orange vessel was launched in v0.22 but that doesn't make much sense either because I've performed several rendezvous missions with three other vessels exactly like it, launched at the same time.

[Soda Popinski]

There's a bug that happens sometimes that undocked ports get "locked" so they won't dock. If this is the issue, you can either undock something else on the craft, which resets them, or edit the save file to fix it. Here's a link: http://forum.kerbalspaceprogram.com/threads/47768-Locked-Docking-Ports

[Blue]

Thought it might be that. I'll double-check.

[Decent Weasel]

I know you think my advice isn't great, but have you tried accelerating before docking? Like I said before, I've had the same problems as you, and applying a tad more speed helped immensely. You said it was 'the worst advice you'd ever heard' but didn't explain why and gave no indication that you'd tried, so I'm wondering why you've concluded it's bad advice.

[Superfluous J]

I have a theory, based on a very scant bit of evidence.

Right around 0:15 your space station seems to tilt EVER SO SLIGHTLY. Like, a pixel or 2, downward.

I think that the port on the station sees one of the other ports on your ship, and pairs with it. Until you back away and try again, it'll only attach to that port and not the one you're slamming into it.

It's a guess, and probably a bad one, and as I said the evidence is scant. But it fits what we're seeing.

[Blue]

I know you think my advice isn't great, but have you tried accelerating before docking? Like I said before, I've had the same problems as you, and applying a tad more speed helped immensely. You said it was 'the worst advice you'd ever heard' but didn't explain why and gave no indication that you'd tried, so I'm wondering why you've concluded it's bad advice.

My apologies, I did not connect you to the Youtube account.

That website's atmosphere being what it is, I assumed the comment came from a troll trying to confuse and hinder new players.

There's a bug that happens sometimes that undocked ports get "locked" so they won't dock. If this is the issue, you can either undock something else on the craft, which resets them, or edit the save file to fix it. Here's a link: http://forum.kerbalspaceprogram.com/threads/47768-Locked-Docking-Ports

Thank you very much, this solved the problem. I figured as much, I just couldn't figure out how to find the "Acquire" problem state until I found it.

Edited December 27, 2013 by Blue

[FlamedSteak]

We've all put them on backwards before, there's no shame in it. I still often screw up mounting the Senior ports, I really wish Squad would put a "This side facing stoopid" label on the docking ports.

Nothing worse than spending an hour launching, rendezvousing, carefully lining them up and then watching them bump into each other like halfwitted blind donkeys.

In this case though, I can't see anything to suggest why they didn't link up. Has to be a bug, potentially due to the massive size of what you're trying to dock together.

Edited December 27, 2013 by FlamedSteak

[Decent Weasel]

My apologies, I did not connect you to the Youtube account.

That website's atmosphere being what it is, I assumed the comment came from a troll trying to confuse and hinder new players.

Oh, cool, awesome.

Yeah, sometimes Youtube gets crazy / horrible. Glad you figured it out!

[ArmchairGravy]

We've all put them on backwards before, there's no shame in it. I still often screw up mounting the Senior ports, I really wish Squad would put a "This side facing stoopid" label on the docking ports.

Nothing worse than spending an hour launching, rendezvousing, carefully lining them up and then watching them bump into each other like halfwitted blind donkeys.

In this case though, I can't see anything to suggest why they didn't link up. Has to be a bug, potentially due to the massive size of what you're trying to dock together.

Ah, bittersweet memories of my first attempt at a space tug. When I realized the port was on backward after an hour's worth of attempt, people in the next county probably heard me cussing.

[Blue]

We've all put them on backwards before, there's no shame in it. I still often screw up mounting the Senior ports, I really wish Squad would put a "This side facing stoopid" label on the docking ports.

Nothing worse than spending an hour launching, rendezvousing, carefully lining them up and then watching them bump into each other like halfwitted blind donkeys.

In this case though, I can't see anything to suggest why they didn't link up. Has to be a bug, potentially due to the massive size of what you're trying to dock together.

"Success is the child of audacity."

[Pi_]

We've all put them on backwards before, there's no shame in it. I still often screw up mounting the Senior ports, I really wish Squad would put a "This side facing stoopid" label on the docking ports.

Actually, there is... the little yellow triangle indicates the non-docking side.

[SSSPutnik]

We should really have a sticky on docking ports, keeps popping up.

[Superfluous J]

Actually, there is... the little yellow triangle indicates the non-docking side.

I think they were asking for something obvious, and perhaps intuitive. Like, say, removing the "+" symbol that implies "yes!"

I've always just looked for the handle on the door with the little yellow hand-hold.

[Blue]

Information on that docking port thread would include:

-Construction Techniques.

--Where to put docking ports.

--What they do.

--What can be attached to (they can act as radial/node attached fuel lines to engines) and what they should not (parachute holders).

--Benefits of multiple docking ports vs. larger docking ports.

-Behaviours of docking ports in normal conditions.

--Stress limits when docked.

--Impact limits when approaching.

--The Magnetic approach pull.

-Bugs associated with docking ports.

--State = Acquired or Predocked Save bugs.

--Unseperated debris.

---Etc.

Because the only other parts I can think of that deserve their own thread would be Science parts (which get many).