How to dock in KSP

So, you're going somewhere else in the Kerbol system huh? And when you get there you want to land and grab some of that sweet sweet science

that awaits you on the surface. Problem: your lander ship is also your mothership, and you expended all of your fuel landing and dont have

enough for liftoff let alone getting home.

The solution: A mothership! It flies you around, carries extra fuel, and a dedicated lander gets you up and down from the target body.
New problem: you dont know how to rendezvous with a ship in orbit, let alone dock with it. Well, here's how I do it.

First off, you'll need a docking target vessel of some kind for practice. A medium 2.5m tank with a probe core, some batteries, an SAS

module, some solar panels, an engine (or engines) and a docking port would work adequately. Get this into a moderately high 300km equatorial

orbit, and make it mostly circular. A little eccentricity and inclination is ok, not all orbits are 100% perfect and KSP's floating point

errors will fuck it up anyways.

Once you have your docking target up in space, you need to construct/modify your docking vessel (the ship you will be in control of).
The hard part about the docking vessel design is the RCS placement, as it must be balanced. Its possible to do it with a single set of RCS

thrusters, but mass shifting through fuel and RCS expendeture will make it difficult. You will need 2 sets of 4 RCS thrusters, quad blocks.
First, turn on the center of mass indicator in the VAB. This will make the yellow orb that tells you where the vehicles center of mass is. If

you are modifying an existing vessel that is attached to a rocket, pull the rocket before doing this.
Next, select x4 symmetry and grab the RCS quad block from the part menu.
After that, place 2 sets around the vessel: 1 above the center of mass, one below it. Make sure there's roughly equal distance between both

RCS sets and the center of mass.
Finally, if the vessel doesnt have it, add some RCS tankage (a couple of the pill tanks will do) so your RCS thrusters arent dead weight.
After this is all done, make sure the vessel has a docking port that is compatible to the one on the target vessel (small port on the target,

small port on the ship; medium port, medium port, etc).

Grats, you now have a ship capable of docking. Now to actually do it.


First, get your ship into space (80km circular orbit with inclination below 5 degrees is a good starting point). Get Kerbal Engineer or

Mechjeb for the orbital info, it makes this *MUCH* easier.
Go into map view and set the docking target ship as target (right click and select set as target).
Pop the navball out, you wont be going back to the normal view for a bit.
Now, you will notice that when you set the docking target as a target, a number of extra indicators popped up. We'll go through these one at

a time.

First, look for the grey dotted lines linking your orbit with the targets, and capped at the target's ends with small green arrows with AN

and DN in them. These are your ascending and descending nodes relative to the target. They are the points where your orbit goes higher or

lower compared to the target. Mousing over one of these green arrows will give an inclination number in degrees. You want this number as low

as possible.
Pick one of the green arrows, and click on your orbit to create a maneuver node. You will see the 6 pronged node editor pop up, and you will

want to focus on the purple triangles above and below it. Tug on these until your post-node orbit (the dotted yellow orbit) matches the plane

of the target orbit (the AN/DN should read within .1 degrees. 0.0 or NaN is optimal).
Burn that node, and your current orbit should now match the plane of the target orbit.

That was the easy part. Now you have to actually get to the target, and it will involve alot of fucking around with the maneuver node to get

it right.
Now, I'm assuming the launched ship was launched into the aforementioned 80km circular orbit. In this case, you want to go higher, and that

means prograde. Create a maneuver node, and pull the yellow circle until your projected orbit is high enough to get to the target orbit. If

they havent already, a number of magenta and orange indicators and dotted lines should pop up. What you want is for one pair of orange or

magenta arrows to match up. You will need to tug on the prograde/retrograde indicators on the node a bit.
If the indicators are too far off for adjusting the orbit to compensate for, you will need to move the maneuver node itself.
Click and drag it around your orbit until the arrows line up (if they do). If they dont, try time-warping a couple more orbits ahead, then

try again. Eventually you will get lucky.
Here's where precision is absolutely necessary. Execute the node (fly it in map view, using the nav-ball to do it), but keep an eye on how

your orbit is moving relative to the desired result.
Dont feel discouraged if you complete the node and you're still a couple km off. You have RCS thrusters. Use em after the main burn to fine

tune your orbit so that the indicators in map view show less than .5km difference. If you want to go closer, go ahead, but make sure to leave

some distance so you dont plow right into the target.

While you are coasting to the target, click on the velocity indicator above the Navball and set it to relative velocity (Should read Target:

<velocity in m/s>). This is important, as it will help you match velocities with the target once you get there.
Return to the normal view, and on the navball, orient your ship so it is prograde with the target (if you were dropping in from a higher

orbit, it would be retrograde with the target). When the target ship in the normal view (it should be little more than a green indicator with

a number beneath it) is within 5-10km of your ship, begin the burn to match velocities. Ideally done, the target should be within render

distance (2.3km), and the relative velocity between you and the target should be near 0.

Point your ship towards the target (big purple split circle with a dot in the center on the navball) and thrust towards it (using your

thrusters. The engine is no longer needed). Your relative velocity vector (yellow prograde symbol) should be overlapping the target indicator

on the navball. As you approach, you may need to thrust a little bit more to unt for drift between you and the target.
Slow down to a stop once you are within 50-100 meters of the target. Congrats, you have successfully rendezvoused with the target ship. Now

to dock with it.


From your ship in the normal view, right click on the desired docking port on the target, and in the context menu that shows up click "target

docking port". On your own ship, right click on your docking port and click "control from here". Your docking port is now the controlling

part of the entire ship, and if its not on the end of the ship (ex on the nose of a capsule), your entire control scheme will re-orient

itself with the new control part.

Anyways, once that is done you need to line up the docking ports on both you and the target. The mod Docking Alignment Indicator is a GODSEND

for this, as it gives you all of the information needed to line up and dock. Seriously, get it. It will make lining up with the target so

much easier.
Once you have lined up your port and the target port, thrust forward a little, making sure to adjust to keep the alignment as you fly along.

You'll know you got it when the magnets engage and drag your ship and the target together. When this happens turn off your SAS if its still

on so your ship can move freely. It may get it instantly, or drag around a bit, but once the ports have begun to attract each other docking

is pretty damn well assured.

And there you have it: How to dock 2 ships together as explained by CyriousLordofDerp