Ultra noob at docking..

[HMIMH]

Hello guys! I've been playing ksp and in 1 year I only did flies to Minmus and Mun. Now I wanted to build an ISS (no idea how yet) and learn docking. The tutorial docking scenario is EXTREMELY hard for me. There's no way I can dock, or stay on an asteroid. My vessel starts spinning around the objective pointing towards it. And if i'm lucky and I get to stay "stopped", the docking port is at other side. I mean, the objective is vertical and my vessel horizontal, and If i move it starts spinning again. Very frustrating i swear.. Sorry If it sounds very noob, im new here and i'd love to learn. Thanks! 

[Snark]

Hello, and welcome to the forums! 

On 2/14/2018 at 9:04 AM, HMIMH said:

Hello guys! I've been playing ksp and in 1 year I only did flies to Minmus and Mun. Now I wanted to build an ISS (no idea how yet) and learn docking. The tutorial docking scenario is EXTREMELY hard for me. There's no way I can dock, or stay on an asteroid. My vessel starts spinning around the objective pointing towards it. And if i'm lucky and I get to stay "stopped", the docking port is at other side. I mean, the objective is vertical and my vessel horizontal, and If i move it starts spinning again. Very frustrating i swear.. Sorry If it sounds very noob, im new here and i'd love to learn. Thanks! 

Heh, don't worry, we've all been there!

So, broadly speaking, there are two skills you need to master in order to dock:

1. Rendezvous.
2. Docking.

Rendezvous consists of being able to navigate your vessel so that you end up parked at zero relative velocity, very close to the target.  From your description, it sounds like you've already got this one down, so I'll assume you don't need any pointers there.  (If I'm wrong and you do need some help with that, here's an illustrated guide to rendezvous that may be helpful.)

Docking is what happens after you've successfully accomplished a rendezvous, and consists of all the fiddly maneuvering to get things lined up and then attached.  Here's an illustrated docking tutorial I made, which you may find helpful.  It's a bit old (which is why the screenshots may look a little dated), but the information in it is still accurate in KSP now.

All of the above are assuming that your ship is designed okay, and that your only difficulty is with the piloting.  However, I do note this one comment you made,

On 2/14/2018 at 9:04 AM, HMIMH said:

If i move it starts spinning again

...which is a bit confusing to me.  If you've got SAS turned on (which you do, right?), then it ought to hold you fairly stable in orientation-- you shouldn't start spinning unless you've told the ship to rotate.  If you find that trying to do docking maneuvers is causing your ship to start spinning, one possibility would be that your RCS thrusters are badly placed (e.g. far off-center) in a way that they can't do their jobs properly.  If that's your issue, then it's easily fixed-- but we'd need to see a screenshot of your ship to confirm, so we can give concrete advice as to how to tweak the placement in order to work better.

[HMIMH]

10 minutes ago, Snark said:

Hello, and welcome to the forums! 

Heh, don't worry, we've all been there!

So, broadly speaking, there are two skills you need to master in order to dock:

1. Rendezvous.
2. Docking.

Rendezvous consists of being able to navigate your vessel so that you end up parked at zero relative velocity, very close to the target.  From your description, it sounds like you've already got this one down, so I'll assume you don't need any pointers there.  (If I'm wrong and you do need some help with that, here's an illustrated guide to rendezvous that may be helpful.)

Docking is what happens after you've successfully accomplished a rendezvous, and consists of all the fiddly maneuvering to get things lined up and then attached.  Here's an illustrated docking tutorial I made, which you may find helpful.  It's a bit old (which is why the screenshots may look a little dated), but the information in it is still accurate in KSP now.

All of the above are assuming that your ship is designed okay, and that your only difficulty is with the piloting.  However, I do note this one comment you made,

...which is a bit confusing to me.  If you've got SAS turned on (which you do, right?), then it ought to hold you fairly stable in orientation-- you shouldn't start spinning unless you've told the ship to rotate.  If you find that trying to do docking maneuvers is causing your ship to start spinning, one possibility would be that your RCS thrusters are badly placed (e.g. far off-center) in a way that they can't do their jobs properly.  If that's your issue, then it's easily fixed-- but we'd need to see a screenshot of your ship to confirm, so we can give concrete advice as to how to tweak the placement in order to work better.

First of all, thanks you so much for your detailed and kindness answer! 
I will try to explain as accurate as possible now. 

Everything you listed is right, rcs, good design, SAS on..
What I meant with "start spinning" is that I never could get roughly lined up. I mean, the two ships had their docking ports looking other sides like this pic from your guide.

After reading your very useful guide (thanks, for real) I realized that, as I was in the tutorial, I could't move the other scenario-to-dock-in ship!! So it was nearly impossible align my vessel with the static (and uncontrollable) one. Thinking it now, it's easier to align them if I control one, then the other and I align them, not only one as I tried in the tutorial. 

[Snark]

56 minutes ago, HMIMH said:

I realized that, as I was in the tutorial, I could't move the other scenario-to-dock-in ship!! So it was nearly impossible align my vessel with the static (and uncontrollable) one. Thinking it now, it's easier to align them if I control one, then the other and I align them, not only one as I tried in the tutorial.

Ah, glad it worked out for you! 

FWIW:  Even though it's usually easier if you rotate both vessels... sometimes it's only practical to rotate one of them.  For example:  Suppose you're building a great big massive space station with many parts all docked together.  When a structure gets bigger and bigger, it becomes very hard to rotate it (because the moment of inertia goes up with the square of radius).  So, if you have a big ungainly space station, it might not be practical to rotate it as needed.

So... if you end up in a situation such as the screenshot above, and if the big ship is so big it's only practical to maneuver one of the ships (i.e. the little one) ... that's doable, just rather more inconvenient and tedious.  Basically, it means you need to fly your ship over to a location where it's located approximately in front of the other ship's docking port, and then follow the steps in my tutorial.

For example, in the screenshot above, imagine if the ship with the big orange tank were essentially immobile and you couldn't rotate it.  What would you do?  Well, what you could do is, turn that little ship around so it's pointing towards the left edge of the image (and maybe a little bit upwards), and give it a teeny-tiny goose with the engine to send it drifting slowly in that direction.  While drifting, rotate 180 degrees so that the engine's pointing forward.  Wait until it drifts to where it's approximately in front of the big ship's docking port, then another brief engine burst (or a touch of RCS) to bring it to a halt.  Then do the docking maneuvers.

[Spricigo]

well..I have tried a few times to use only words to explain the docking procedure... turned out be a proof that a image can tell more than a thousand words when what finally helped was something with Images.

So, now I prefer to just point to the nicely crafted guides by Entropius , Snark or Necrobones  (Link for the first two in Snark's post). There are other good guides available, those are just what I tend to have on top of my head (or at least in the first page of google ) . My only addition is: practice and experience will make it easier, maybe even second nature.

[Human Person]

5 hours ago, HMIMH said:

My vessel starts spinning around the objective pointing towards it

this is an indication you use the wrong reference frame. Make sure you are in Target mode for docking, and arrest your velocity by burning retrograde.

 

Edited February 14, 2018 by Human Person

[Fearless Son]

6 hours ago, HMIMH said:

Everything you listed is right, rcs, good design, SAS on..
What I meant with "start spinning" is that I never could get roughly lined up. I mean, the two ships had their docking ports looking other sides like this pic from your guide.

After reading your very useful guide (thanks, for real) I realized that, as I was in the tutorial, I could't move the other scenario-to-dock-in ship!! So it was nearly impossible align my vessel with the static (and uncontrollable) one. Thinking it now, it's easier to align them if I control one, then the other and I align them, not only one as I tried in the tutorial. 

@Snark's guide is indeed very good, but I if I were to amend it with my own experience, I would add emphasis to the use of the translation controls (H, N, I, J, K, and L.)  Turn RCS on and practice with them a little, as being comfortable with them will save you a lot of frustration.  If you can get your velocity zeroed near your target, and your docking ports are facing parallel directions, you can translate laterally until they are lined up and just use a little forward translation to bring them into a dock.  

One other thing that the guide does not mention is remember to deactivate your SAS just before your docking port makes contact.  Your SAS in stability mode will try to keep the ship facing the same direction.  However, the ship needs to change it's facing, at least in a minor way, to get the docking ports lined up.  The magnetic forces in the docking ports will do this automatically for you if they are close enough, but those magnetic forces are relatively weak and cannot overcome most SAS torque forces.  Otherwise your ships will just end up bouncing off each other without connecting.  So at the last moment let the stability go and allow the magnets to take over.  So long as you are close enough and slow enough, this should be enough.

[Warzouz]

Here is how I learnt to dock

- Install Mech Jeb
- Use the auto rendez-vous feature
- Be attentive to how it does
- Use Autodock feature
- Be attentive how it waste so much fuel !
 

After several docking
- Redo what MJ has done (start with docking, before rendez-vous)

After several docking
- Improve on what MJ usually do. Be smarter

To ease docking use "Alignment port indicator" mod. Be sure to properly set all you control keys, especially for translations.

And BTW a quick design advice : don't add much monopropellant tanks. You only use a tiny bit if you take your time. I can dock 3 times a 7T ship with 10 units of monoprop. I never use additional Monoprop tanks, except in refuel station. The secret is to go slowly. If you want ton go faster, don't use thrust, use timewarp.

Another design advice : place your solar panels and other fragile stuff far from the docking rings. So, if you miss, you don't wreck everything...

Also : try to design your station mostly the same way. Docking ports always in the same location. So you don't need to think were your docking ports are. Don't hesitate to use colors on the lights, again to see where you have to go from afar.

And again : add lights toward your ports so you can  see them

Docking advice : orient your target ship always in the same direction, so you'll find your marks even if you don't see the docking ports.

Alternative advice (best for small ships docking with small ships), set both ships to "target" aim, ans simply move toward each other.

 

Finally, be aware that Kerbin space stations have very little advantages. You'll rarely need to dock to them. On the opposite, having space stations around Mun, Duna or any other planet is usually very useful for refueling landers so you can harvest science points.

Have fun.

[ZootinZack]

For either docking or capturing objects with the Claw, I like to get close (50m or less), usually I use MechJeb because the process itself is tedious.

Remember to switch to "control from here" on the port that's going to do the docking. Make sure you're on Target mode of course. Then use HIJINK keys. They get a few tries to get used to but it's quite literally impossible to mess up a dock after that. Sometimes it gets finicky so remember to use the rotate Q and E keys...