I docked! Here are a few tips that finally helped me.

[jedensuscg]

So after days of frustration I finally docked my refuel ship to my refuel station. I scoured the web for tutorials, videos, anything. In the end I just took it slow.

I was able to get a CPA of around 40 meters. But I could never close to docking range. My trouble was not the docking but the intercept. Here is a basics of what I did that were different from what was messing me up.

I TOOK IT SLOW!

Yup. My target was the Alaska Orbital Refuel Station. My rocket was the MRV (Kodiak Replenishment Vehicle) designed to top off the stations huge tanks (which were empty for takeoff to save weight). The Alaska was in 105km orbit.

I launched the Kodiak to arrive in a 102 km orbit just trailing the Refuel Station. I then circularized. Due to complications with lift off, I had about a 3 degree inclination error between the two vehicle, so I first focused on getting within a .01 inclination of each other. I used Mechjeb for all information output. Once I got that done, I focused on getting an CPA (Closet Point of Approach) to less than 1k. This was done by adjusting the orbit of the Kodiak to be lower or higher then the Alaska. If your orbit is less then your target you will have a higher orbital speed, and vice versa.

When I had a CPA of less then 1k, I then focused on matching orbits in terms of altitude. I focused on keeping the Kodiak no more than 2km lower in orbit. Once I had a near identical orbit with less than 1 km of separation, and 2 km of orbital elevation difference I waited until the Kodiak rocket slowly closed the separation to within 100 meters. It did take a few orbits and time speed increase. I also quick saved frequently.

Now here is where it got hard. Originally I tried to get a close CPA to fast. I would still be several thousand km out from my CPA, but I was trying to burn towards my target until I got a low CPA...this meant I had a high closure rate (relative velocity) and my orbit was jacked up, so I would sling past my target, and my orbit would be very parabolic. This is bad.

This time around, as I said I took it slow. I actually waited until I got within 1 km of the point at which my rocket and the station would be at their closest, then I began to shrink down the CPA with small burns. I actually passed the initial CPA before I was in docking range, but because I took the time to get matching orbits, I just had to wait until the next CPA.

To get an intercept I would burn towards target, not exceeding 20 m/s. When I hit 20 m/s I would burn retrograde to target velocity (if your using Mech jeb, on the SMART A.S.S tab go to TGT and hit RVEL- button) to halt my relative velocity to around 10 m/s. I would then wait until I got a bit closer and do it again, using no more then 50% throttle and never exceeding 20/ms relative velocity. I had near matching orbits, so I had all the time in the world, and doing small burns would help not mess up your rockets orbit.

I finally got my rocket within 5 meters. I then halted ALL relative speed. and just sat there, and learned the docking controls a bit before making my final approach to dock. I also took this time to set up my target with an orientation that would make a good docking approach. My rocket did not have the typical docking ring on the nose like some, nor did my station.

What I learned

1) The key is NOT to focus on getting from several hundred meter CPA to <10 CPA in a single burn, this will give you too high of a relative speed and send you flying at your target, it will also change your orbit in relation to the target to much, so that if you reach your CPA and are not ready to dock, then your next CPA could be way out of whack.

2) Once you get a CPA of <1km and your orbits matched, wait until you are closer to your CPA before you try and close even more. Again don't be so focused on getting that CPA under 10 meters too much to soon, as you will cause your orbit to change drastically. I think I had a CPA of around 100 meters when I was less than 1000km from the CPA point. I passed this initial CPA point with a CPA of 30 meters, but I was set up for a perfect approach on the next CPA. If I had tried to hard to force an approach at the first CPA I passed, I would have either slammed into my target (did it once) or change the eccentricity of my orbit and forced me to have to spend time adjusting my orbit to match the target again.

3)More RCS! I had issues docking because I had poorly aligned RCS, and thus could not translate well. I had 2 RCS thrusters on the nose, placed the same way, so I could rotate up and down, and translate forward and back, but had only SAS to rotate left and right (and no true translation as the rear of my rocket had to RCS, and so it acted as a pivot point even when I tried to "strafe" side to side)

4)TAKE YOUR TIME and save whenever you reach a new milestone.

This was the initial tutorial that helped me. In all I spent about 5 days, several hours each day trying to get an intercept to dock, but once I slowed down, It was one of the easiest things I have done. The actual act of docking took me another hour or so, but again this was because my rocket had poor maneuverability in docking mode. BUt here is a quicky on how I docked.

Docking mode is easy to use once you learn the controls. The main control you NEED to remember is SPACEBAR. This switched between rotation and translation

Rotation is just that. If you have it set to ROT (rotation) at the bottom left, when you press up or down it will rotate in that direction, same with side to side.

Translation is "strafing" or "Sliding". If you have it set to UN (blue light at the bottom) when you press up or down the rocket will accelerate or brake. This is important. This is how you slow yourself down on your approach to dock, without having to spin the entire rocket down and burn prograde. Translation is also how you will line up your docking rings. Pressing Shift or CTRL will "slide" the entire rocket up or down, and A and D will strafe or slide left and right..HOWEVER if you do not have RCS in both the rear and front of the rocket, then it will rotate instead. This was my problem. You can still dock, you just need to steer the ship around to line up your rings instead of just slide into alignment. (i.e if you left of the targets docking ring, you need to rotate right, and translate forward to change you vector then rotate back left and translate forward again.)

take it REAL slow when trying to dock.

Hope this helps a little bit more.

The refuel mission. Also attaching an extra light and Mono tank.

[Claw]

These are great tips!

The other thing that helped me greatly was learning that you can drag the maneuver node around. So once your orbits are on the same inclination, you can put in a maneuver node to match the elevations. When the maneuver node is "open," just left click and hold on the white circle and drag it around the orbit. It works wonders for fine tuning the "closest approach."

How this really helped me was that I could keep the orbits further apart at the beginning. It allowed me to sync up the elevations a bit faster and without having to warp time so much if they start out on opposite sides of the orbit.

[Aphobius]

So you've docked for the first time and thought it's about time to make a tutorial.

[jedensuscg]

So you've docked for the first time and thought it's about time to make a tutorial. http://static-cdn.jtvnw.net/jtv_user_pictures/chansub-global-emoticon-ddc6e3a8732cb50f-25x28.png

Wasn't as much a tutorial as what helped me overcome the many struggles I had with docking, little things that no one else mentioned and I found useful. I am sorry, but until they say you have to be a master rocket scientists to share tips that helped you personally and might help others, please don't be a passive aggressive debbie downer.

Claw, ya I make extensive use of the maneuver nodes for everything. The hardest part for me was realizing I did not need to close my CPA all in one go and early on, but just had to take is in steps, something that the nodes make hard because of their inability to do really finite adjustments. Then last few hundred km's was just using the navball queues.