what am i doing wrong with these docking ports? and how do i read the docking port alignment indicator?

[putnamto]

can anybody tell me what im doing wrong with this? ive tried four almost four hours today and yestarday to try and get these to dock and every time they either touch and nothing happens, or the orange tanks spin around like in the video.

ive checked that the ports are on in the right direction, and ive also checked the persistance file. as for the persistance file i dont really know where to look but i found a part under the ship titled largedockingport, and its state was set to ready.

im completely frustrated, help me guys.

[IncongruousGoat]

Was either docking port offset at all into the part it's attached to? Because it might be an issue with part occlusion.

[bewing]

I think the basic problem is that you're not coming in perfectly straight. That technique works OK when you're docking something small -- but it looks like your craft is really massive.

I'd say -- come in to about 3 to 5 meters. Then stop. Realign laterally so that all your target icons are on the central crosshairs. Then go forward.

 

[micha]

57 minutes ago, bewing said:

I think the basic problem is that you're not coming in perfectly straight. That technique works OK when you're docking something small -- but it looks like your craft is really massive.

I'd say -- come in to about 3 to 5 meters. Then stop. Realign laterally so that all your target icons are on the central crosshairs. Then go forward.

 

Along with this - turn off SAS on your final approach (make sure your craft is under control when you do!).  SAS will fight against the magnetic coupling of the ports.

[putnamto]

2 hours ago, IncongruousGoat said:

Was either docking port offset at all into the part it's attached to? Because it might be an issue with part occlusion.

nothings offset

1 hour ago, micha said:

Along with this - turn off SAS on your final approach (make sure your craft is under control when you do!).  SAS will fight against the magnetic coupling of the ports.

sas is off

 

2 hours ago, bewing said:

I think the basic problem is that you're not coming in perfectly straight. That technique works OK when you're docking something small -- but it looks like your craft is really massive.

I'd say -- come in to about 3 to 5 meters. Then stop. Realign laterally so that all your target icons are on the central crosshairs. Then go forward.

 

im going to try this, but i swear i have come in so many different ways now it should have docked,

speaking of the alignment icons, i get that the orange circle is your angle, if its in the middle you are parrallel to the port, and the yellow symbol is prograde retrograde, what are hte green lines for, and the orange tick that floats around the circle?

speakin of size, the ship is just an orange tank with rcs and electrics.

thanks for your suggestions guys, ill try again when i get time to play.

[micha]

11 minutes ago, putnamto said:

sas is off

Ah, apologies, you do turn it off just before/after first contact.
 

11 minutes ago, putnamto said:

speaking of the alignment icons, i get that the orange circle is your angle, if its in the middle you are parrallel to the port, and the yellow symbol is prograde retrograde, what are hte green lines for, and the orange tick that floats around the circle?

speakin of size, the ship is just an orange tank with rcs and electrics.

thanks for your suggestions guys, ill try again when i get time to play.

Orange circle is your alignment to the target docking port.

The orange tick is your rotational alignment to the target docking port. Only useful for pedants who like everything nice and neat; it can be ignored really. Personally I like it at the "north" position.

Yellow symbol is your current heading (changes whether you are approaching or departing relative to the target port).

Green lines are your "horizontal" lateral velocity relative to the target docking port. They will turn red if you are facing away from the docking port instead of towards it.

On final approach. the orange circle and yellow circle should both be bang on the centre crosshair.
The green lines should be lined up on the horizontal and vertical axes  respectively.

If you're still having trouble, how about sharing your save to see if anybody else can see what's wrong? (Assuming it's not too heavily modded..)

EDIT: So basically, looking at your video again, you still have a fair bit of lateral motion before you touch the docking port. With a heavy ship that might be too much momentum for the ports to overcome and thus prevent capture.

Edited April 1, 2019 by micha
replaced "horizontal" with "lateral" - better term

[Ron Devu]

I went through something like this today. It turned out I had not opened the cover on the docking port! As for the SAS, I usually shut it off 2-5 meters out, while approaching at 0.1 or 0.2 m/s, otherwise the reaction wheels and RCS will go ape. Be sure you are controlling from your docking port and the target is also a docking port.

[putnamto]

ok, now im just begining to think that my docking port sr.s are bugged or something, theirs no magnetic attraction at all with them.

just a little bit ago i tried sending up 2 test crafts to try and practice docking, they were both copies of the same ship, a t400, spark, rcs, sr. port, and probe, they were docked together when i set their orbit, undocked one of them, flew it out about 100m away, spun it all around and such and tried to redock, aaand nothing, they would touch and spin wildly out of control no matter how slow i was going.

any idea what is causing this?

[Zhetaan]

3 hours ago, putnamto said:

any idea what is causing this?

Are those stock docking ports?  I ask because the handrails seem to protrude more than the stock Clamp-O-Trons, and I see lights on the face of the one that are not familiar to me.

[scottadges]

32 minutes ago, Zhetaan said:

Are those stock docking ports?  I ask because the handrails seem to protrude more than the stock Clamp-O-Trons, and I see lights on the face of the one that are not familiar to me.

It looks like he's got Restock/Restock+ loaded, since the RCS tank looks like Restock.

Something I'd recommend (which you might already know about) is this mod: 

It allows you to see your RCS torque & rotation in the VAB/SPH so you can adjust your RCS thrusters to make docking a LOT easier.

A good first question: Are your RCS thrusters balanced around your Center of Mass (yellow globe in VAB)? That will greatly affect how you work with DPAI. If not balanced, the craft will rotate when you fire RCS thrusters, requiring more adjustments in DPAI to get it on the crosshairs.

On 4/1/2019 at 2:30 AM, micha said:

On final approach. the orange circle and yellow circle should both be bang on the centre crosshair.
The green lines should be lined up on the horizontal and vertical axes  respectively.

So to reinforce this comment (depending on how you dock, either using translation or the GUI docking view) it just takes a little practice to get get your craft lined up properly. I find that the magnetic "fighting" happens when you're not aligned and try to dock.

Using the translation keys are really effective docking with DPAI as long as the orange "arrow" is at the top and your craft is properly RCS balanced. That way you line everything up on the center crosshairs and glide in at no more than .5 m/s. It also really helps to right click on the controlled craft's docking port and use "Control from here" so that you know your DPAI is lining up properly.

Then how to correct misalignment?

You want to "push" your yellow prograde marker towards the green lines (either vertical or horizontal) using the translation keys in that direction to get the lines to come back towards centerline. It's not immediate and depends on the thrust power of your RCS and weight of the craft, but once the green line(s) starts coming back in the right direction, you can "push" in the opposite direction to manage your approach.

So from your video: It looks like you're coming in at an angle since your green lines are above and left and you're drifting laterally while trying to to dock.

If you rotate using "Q" so you're at 0 orientation and your orange arrow is vertical, you need to push your prograde marker (yellow) Up and Left using the "I" and "J" keys to get your craft moving in the right direction. Once the green lines drift closer to center, thrust the opposite ("K" and "L") so you balance your approach.

With your orientation off 0, it's just a matter of finding the proper direction your thrusters are pushing, so you get the prograde marker going in the right direction and your lines back to center.

 

Edited April 3, 2019 by scottadges

[Zhetaan]

32 minutes ago, scottadges said:

It looks like he's got Restock/Restock+ loaded, since the RCS tank looks like Restock.

Well, Restock had an issue with the docking node on the Clamp-O-Tron Sr., though that was fixed in the 0.1.3 release.  There's definitely magnetic attraction; I can tell from the jump in closing velocity shown by the alignment indicator in the video.  But with no SAS to interfere, the only reasons I can think of for why it won't dock are either that those are mod docking ports that require specific orientations to lock, or that there's a problem with the docking node.

I am curious about the sudden pitching after the magnets mated but it didn't dock.  With no SAS, had something kicked the docking port away, it wouldn't have registered as an input of pitch authority on the indicator at the lower left.

Edited April 3, 2019 by Zhetaan

[putnamto]

im using restock, and rcs buildaid.

what i meant by no magnets is that on my test craft the ports would touch and either kick one of the craft away, both of the craft away, or do nothing. i get in the normal range when a regular port would start to magnetize and the SR's do nothing on the test craft.

[putnamto]

SUCCESS!! thank you guys, once i understood how to control the DPAI all was well.

but i ran into a snag, see, i needed to dock with that fuel tank so i could transport it to the mun fuel depot........halfway through transit i realized their was no sr. docking port on the fuel depot, and the engineers didnt have a screwdriver, so i whip up a fast ship and get to the fuel depot before the fuel tank does, hand off the screwdriver, use KAS fuel pipes to transfer fuel, hit F5 to quicksave, then disconnected and started home......when i realized i had only put enough fuel in the tank to get back, but not enough to store, so i hastily reload the save........and im back at the docking port from the begining..........

ksp is almost like the girls in my life in this regard, finnally a breakthrough followed by soul crushing defeat.

[Dafni]

1 hour ago, putnamto said:

ksp is almost like the girls in my life in this regard, finnally a breakthrough followed by soul crushing defeat.

Glad you are enjoying the game

[Scarecrow]

I made a small video showing how the Docking Port Indicator can be used.  You may find it helps.

 

[putnamto]

alrighty, all is said and done, fuel tank attached to the kerbin station, duna probe system also attached to kerbin station and fueled up.

question though, 1819 should be enough dv to get from 250km kerbin orbit to a high circular duna orbit?

[bewing]

34 minutes ago, putnamto said:

alrighty, all is said and done, fuel tank attached to the kerbin station, duna probe system also attached to kerbin station and fueled up.

question though, 1819 should be enough dv to get from 250km kerbin orbit to a high circular duna orbit?

Assuming a reasonably optimal transfer window, 960 for the initial burn, 10 for a midcourse correction, 700 for the capture burn -- should leave you just a bit over 100 left. So "just barely". But don't plan on even a single plane change after you arrive.