Rendezvous Help

[lumpman2]

Now that I can get my refueler into orbit, I need to rendezvous it with my lander. But it seems near impossible to even get clsoe to my target, even afetr burning out my entire orange rockomax tank with a skipper engine. It almost seems like the lander's orbit is below my and not really inclined... I'm not really sure about a good procedure for getting the intersects closer together, since they always stop moving closer once they get about 10 km away.

[bobcook]

There are a gazillion articles with this same question and likely same answer, but anyways here goes the "simple-but-not-necessarily-the-optimal" solution:

(1) launch the first craft into a nice, stable, circular orbit - say 100km

(2) launch the second craft into a nice, stable, circular orbit lower than the first - say 90km

(3) switch to the map view, set the first craft as your target

(4) fix any differences in the inclination (use the manoeuvre nodes to make this really simple)

(5) wait until the separation is less than 100km

(6) raise the orbit of the second craft to ~95km, keeping it circular

(7) wait until the separation is less than 10km

(8) raise the orbit of the second craft to ~99km, keeping it circular

By this point you'll have the second craft approaching the first at a fairly slow rate. Use the RCS to continue to refine the orbit of the second craft until you get an intersection of less than 1km (you can usually get it to 0.3km or less with some care).

Use the target and direction indicators in the navball, use RCS (with SAS enabled) to literally steer your direction indicator until its pointed straight at the target. Use RCS to speed up or slow down so your approach rate is under 1m/s when only a few hundred meters away. Let time pass, you will eventually reach your target.

What is happening here is that your second craft in the lower orbit is going faster around Kerbin that the first craft, which means it will eventually "catch up" to the same point over the planet. But since they are in different orbits, you can never rendezvous. So what you do is use the lower orbit to get "nearly close" then keep raising the orbit until you are very, very close.

This is definitely not very quick, but its very simple to learn and with practice you can rendezvous much faster (align your launches, use lower orbits for longer, etc). Have a lot of patience and resist the urge to timewarp too often until you get the hang of it. Hope that helps.

[alterbaron]

Watch this video:

If you'd rather read, here's a quick guide on how to rendezvous without using too much fuel:

1. Set the other ship as your target in the map screen.
   
2. Match target's inclination (burn at ascending or descending node to do this).
   
3. Burn at apoapsis so that your periapsis lies on the orbit of the target.
   
4. Burn at periapsis to make our apoapsis either a bit higher or a bit lower than your target's orbit.
   
5. Time warp. Every orbit, your "closest approach" markers will move, eventually getting closer and closer together.
   
6. On the orbit where you think the "closest approach" markers will pass each other, set a maneuver node at your periapsis and fiddle with it until you have a close encounter with your target.
   
7. Make sure to burn at the maneuver node.
   
8. Finally, once you are within a few km of your target, burn to make your relative velocity only a few m/s. Then coast to your target.
   

[Tripzter]

(1) launch the first craft into a nice, stable, circular orbit - say 100km

I suggest 130km. 3 easy reasons.

First is 120km is the difference between 4 and 5x time warp so 10k extra as a leeway since as you dock stuff eventually you'll drift 1-2k one way.

Reason 2. Stuff you want to dock with the station only needs to go to 75-80km and have enough of a difference so you're not waiting half an hr in max timewarp to catch up to the station.

Reason 3. With such low orbit you're burning less fuel overall. 80km vs having to go to 150ish k.

[Rhyunix]

I swear this is the thing that comes up every time with orbits SOMEONE make something to help these people!

[blizzy78]

Heh, the first thing I was asked to do after people saw my in-game docking tutorial was to make another one covering rendezvous

[Rhyunix]

Why does this not surprise me.....

[Tripzter]

I swear this is the thing that comes up every time with orbits SOMEONE make something to help these people!

Theres tons of guides on youtube. Not sure why people dont just search for it.

[krenshala]

What I did to learn this was watch a few videos that are already out there, put two ships in orbit, one about 20 or 30 km higher than the the other. Once they were both in a stable orbit I added a maneuver node to the lower orbit that brought Ap up for a possible intercept and started sliding the node around on the orbit to to minimize separation at intercept and when about 4 km out got the relative velocity pointed directly at the outer ship.

Of course, when tired, I ended up with a perfect intercept and smashed the lower (faster) one into the higher (slower) one, because I was worried more about the relative velocity vector and not paying enough attention to the distance. My second attempt, however, went much smoother as I remembered to slow down to 20m/s at about 30km, 5m/s at 3km, 2m/s at 300m, and finally 0.5m/s at 80m, and I was able to dock no problem. Just remember to stay below 0.2m/s once you are close enough for the Illuminator Mk2 to light up what you are docking to and you won't ram it accidentally, and add spin that makes things even more ... interesting.

[Porspeler]

Blizzy78's tutorial vid/page was the resource that helped me the most.

http://forum.kerbalspaceprogram.com/showthread.php/35988-Launch-rendezvous-and-docking

(...)

Of course, when tired, I ended up with a perfect intercept and smashed the lower (faster) one into the higher (slower) one, because I was worried more about the relative velocity vector and not paying enough attention to the distance. (...)

I had a similar experience on my first approach, but it was only beginner's luck that enabled me to avoid a collision. I saw that the separation was going to be only 0.1 km, which got me stoked. I kept fooling around and adding thrust so that I could close the gap more quickly, not paying attention to my velocity in relation to the target. Oops. My target did approach within 100 meters... as it blazed by at nearly 200 m/s.

I'm glad it happened that way, though. It made my eventual success more sweet, because when I finally got my act together and ended up floating motionless a dozen meters away from the target, it seemed almost magical.