Sr. Spacecraft Engineer
That only seems to be the case for very similar orbits on small crafts.
Originally Posted by Scarecrow88
For bigger ships that take longer to dock, the shift can be noticable since you do complete a significant amount of the orbit. It all just makes it harder to line up. You can't go wrong with north/south orientation, so there is no reason why you shouldn't.
Either way, the docking ports have to be facing in opposite directions, so unless you want to do it quickly, or like swapping between spaceships to line them up properly, you can just have one pointing north and then flip the other craft round when you're close enough, knowing that it just needs to face south.
Well, i managed to get within 1.2km... Scott Manly makes it look so easy..
because the problem with MechJeb is it takes the skill out of it. If you wanted to watch someone do it there are plenty of videos of it on Youtube. I know the Devs said MechJeb isn't cheating. I used to think that using Mechjeb on your first anything was taboo, but I am beging to see such action more and more. I have even cringed when I saw someone post in another thread about someone needing help to land on the Mun that said they should get MechJeb. Sure it helps the game become less repetitive but if it is the first time you do something you should not use it.
Originally Posted by nimbim
Some of the guys here gave some pretty good tips regarding RCS, etc.
In case you are still reading this, I usually have a few steps that are generally always the same when I dock:
1. Make orbits very similar
2. Create a point of intersection as close as possible (sometimes it's 0.1km, sometimes it's many KMs). The closer the better.
3. When reaching the closest point, Burn facing the Retrograde symbol in TARGET mode. (this should zero out your relative velocity, must be in target mode!)
4. Use burns or RCS to get a little bit closer to the vessel, easy does it.
5. Small adjustments to make the ports come together very slowly.
Sometimes if I am having a lot of trouble, especially if I don't have RCS, I will right click the port I want to dock to and select it as my target. This way, if the vessel is too large, I can match up my "prograde" indicator to the "target" indicator and head directly towards it.
Not for resale
The first time is always the hardest... I hadn't even really learned the fundamentals of a proper docking yet when I first managed it, and it still took over an hour. Nowadays I can dock practically without thinking about it...
The thing about docking is, it's not meaningfully different from trying to intercept a moon or planet. You want to first get it so that your two vessels will be close to one another at some point in their orbits, and then you want to adjust for the difference so they can maneuver towards one another at safe speeds once you get close enough. Maneuver nodes are great for this, and targeting is essential. Even if you don't use maneuver nodes, the six-point navigation technique can help immensely. This technique is simple enough: fire in one of the six key directions (north, east, south, west, up, or down) and see how it changes your intercept. If you get a better intercept, keep firing. If you get a worse one, fire the opposite way until it stops being very effective. Once you've checked all 6 directions this way, you generally get a pretty good intercept... assuming you've got a point where the two orbits will realistically intercept, of course.
Sanity is for the weak.
Docking was one of my first real attempts since getting back into KSP, so I wasn't (and still am not) especially efficient at or knowledgeable about Kerbal rocket science. I just had what I thought was a cool idea for a space station after watching someone else doing their first time docking, creating a rather crazy looking piece of work.
...My design, as it turned out, was questionable at best. I got the first two pieces up fine and had little problem aligning their trajectories, but RCS was set up terribly for docking. Using docking controls, the module would just start spinning at the slightest correction burn. Extremely frustrating stuff, that was. Eventually (about an hour or two later), I'd pretty much given up careful precision and was just about out of monopropellant fuel, so as I drifted around at an angle with the ports facing, I just launched at it desperately. Unexpectedly, the two parts pulled towards each other fairly quickly (as I said, next to no knowledge here) and started rolling around dangerously close to flying off from each other.
I just stared, wide eyed (quite a feat considering I was half asleep and it was about 2 AM) and scared to do anything in fear that I'd ruin it, and watched. Slowly, the scene calmed before me and suddenly the view rotated and zoomed out a bit, informing me that there was a successful connection. So what if it was horribly lined up? So what if it turned out to be horribly unstable and hard to maneuver? I was so full of accomplishment at the time that I could barely care the least for that stuff. That sort of feeling is not something I think I've gotten from another game before, at least that I remember, and it's definitely something that makes Kerbal Space Program special to me now. Hopefully the first in a number of successful achievements.
Edit: Err....so yeah, time. I'll say a few minutes to get them within 500 m, two hours after that 'til they were officially docked.
That's quite brilliant, actually. I have a bad habit of just dumping my craft in their parking orbit (usually with a loader probe that trashes itself afterwards) so they end up facing any damn direction.
Originally Posted by Sof
Orienting docking ports along N/S is a perfect guide. Say, fly north of your target, orient to south, burn and RCS correct to dock. Three easy steps.
Though, I'm thinking displacing above/below the orbital plane gives you possible collision points at the AN/DN. Even though docking is a controlled collision, it's possibly something for time warpers to think about, maybe?
More boosters, mule!
My first few attempts at docking were disasters that resulted in a cloud of debris so large I gave it a name. I finally got the hang of it, and now happily assemble ships in orbit and dock fuel tankers around other planets.
Here's a step by step tutorial I typed up earlier:
Now. Here comes the start of the tricky bits. Once you've made it into orbit, take note of whether you wound up in front of or behind your target. We're now going to use what I call the HIGH ROAD / LOW ROAD system to get closer. As in “You take the high road, I'll take the low road and I'll be in Scotland before ye!” Your speed is inextricably linked to your orbital height. Higher = slower, lower = faster. So if your target is orbiting at 125Km and is ahead of you then you need to go faster and should make your orbit at 121Km. If you are in front of your target you need to go slower and should set your orbit at 128Km or so. Yes, this does mean that if you need to catch up with a target in front of you you do a series of burns away from them. Yes, every science fiction movie is ruined now. You're welcome.
Anyway, the difference in your orbital heights should be about 3-5KM unless you've totally fluffed your launch window and your target is on the other side of the planet in which case you can go higher or lower to fix that problem more quickly. Once you get closer (1/8th the planet radius or so) you should get within the 3-5KM range.
Once you've gotten into the correct orbit we need to planarize … planify? Plantificate? Nope, spell check doesn't like any of those. Co-plaginate? Nope. Anyway, we need to make our orbits co-planar. To do this, select the orbit target. This may be tricky. Especially if you haven't been keeping LKO clean. The selector algorithm loves selecting debris, followed by ships orbiting the Mun, followed by any other ship in Kerbin orbit. Only if there is no reasonable way it could possibly select one of those will it allow you to select the ship that is right under your pointer. However, if you click it too many times in frustration it will transfer you TO that ship, so be careful and keep your orbits clean. If you can't select the ship from the orbital view you can select it from the main view once you get close enough. Simply wait and then go to the main view. Set your camera to “Free View” so that it remains pointed in the right direction and aim it forwards or backwards depending on who is chasing whom. Remember that the Backbone of Night lies along Kerbin's orbit, so your target should appear along there. Unless you didn't follow my advice above about using an equatorial orbit, in which case GOOD LUCK. You then wait until a purple bracket box appears and double click on that.
Anyway, once you've managed to select your docking target you will now have a second green orbit marked on your map display and somewhere between two and six new markers. The important ones are the ones marked AN and DN for ascending node and descending node – the places where your current orbit crosses the orbit of your target. Set a maneuver node on one and adjust it until your difference is 0.0* If you've done this properly the other four markers should now have merged into two. These show you your closest approach – one marker is for you, the other is for your target. Focus on Kerbin center those markers and turn on turbo time. And wait.
WAIT – Time for a song!
Now, at some point that target position is going to switch from one side of the your position marker to the other. Now is the TIME FOR GLORY.
Switch to your main view, Free Camera. Find your target. If you are in a lower orbit it will appear to pass over you. If you're in a higher orbit it will appear to pass under. If you forgot to make your orbits co-planar it will swing from left to right and you should have FIXED THAT EARLIER. Also, look at your navball. It should now read “TARGET” instead of “ORBIT”. There are also two new markings on it. So, your prograde and retrograde vectors are now RELATIVE TO YOUR TARGET and the new purple marks are TOWARDS TARGET and AWAY FROM TARGET. It will also show you your speed relative to the target. This is an absolute value, so if you are heading towards the target at 5ms it will show “5ms”. If you're heading away at 5ms it will ALSO show 5ms. This isn't normally a problem, but keep it in mind.
Now, we need to start moving towards our target. Switch to Chase View and rotate the camera away from the side on view (seriously, has anyone ever used the chase camera in any position other than behind and slightly above? I've wanted it off to the side like that approximately NEVER times, but I HAVE lost half a dozen planes while trying to fight it around to a useful position). Find the TOWARDS TARGET icon and if you can see your FORWARD marker then set your heading so that it is on the opposite side of the TOWARD TARGET icon from your FORWARD marker and thrust. Use your main engine if you can – the first rule of orbital rendezvous is that you never can have enough RCS gas, so you should spare it if you can. Anyway, thrust until your forward vector is now heading toward the target. I generally try and keep my speed equal to roughly my distance / 100. So if I'm 3.5km away, then I should be going about 35ms. You may need to change this if the ship your trying to dock is exceptionally sluggish. Now as you get closer you need to slow down and keep your vector pointed at the target. If you boost towards your target your forward vector moves TOWARDS your heading. If you cut it moves AWAY. So if you've drifted off to the left and want to correct that AND slow down, then you point your ship in a heading that is on the far side of your vector from the target icon and decelerate which will both bleed off a bit of forward velocity and “push” your heading back towards where you want it to be. Now, once you get within 2.2Km KSP will load the other ship. This will cause a momentary spike of lag that can range from “noticeable” to “time to go get a sandwich” depending on how large your target is and how beefy your computer is. Try not to be doing any violent maneuvering as you pass that threshold. Once you get to about 1.2Km it will switch from KM to M and you will usually immediately panic as that number seems to suddenly be getting smaller faster than it was a minute ago. Just stick to the 1/100 rule and you'll be fine. The first time you try a rendezvous you'll usually be going way too fast. 20M/s is pathetic by interplanetary travel standards, but when you're trying to dock with another vessel that is only tens of meters away you suddenly remember that 20m/s is about 55 mph.
Once you get to about 100m away from your target, quicksave, kill your forward velocity, turn on your SAS, turn on your headlight if necessary and find your docking port. If you need to switch over to the other ship for a second you can do so now, just try to leave your other ship gently floating away so that if you take too long you don't suddenly get rammed. Once you've found your docking port, GENTLY RCS over to it. You may want to hit “fine controls” at this point as well. Keep in mind that it may be easier to switch over to the target vessel and rotate it around than try and fly in a circle around to a docking port on the far side of a craft. Now, get perpendicular to your target docking port. Now use your translate controls (remember those?) to get lined up with your docking port. Now gently thrust towards it. Once you get with 50M you can right click and select the port and target it. This makes one important change. All the markers on your navball are now relative to the docking port. Make sure you're still lined up and correct as necessary. Once you get with a meter or two the ports will pull towards each other. If the ships are bouncing too wildly you can try and correct with your RCS jets, but you generally just leave them alone and let your SAS dampen the bouncing enough that you actually dock.
Once you're docked you can transfer fuel by selecting a fuel tank and then alt-selecting a second fuel tank (or RCS tank) and using the “in” and “out” buttons to transfer fuel and oxidizer.
You should be good to go at this point. Good luck up there!
Last edited by Unistrut; 7th July 2013 at 20:50.
Space and Ponies.
I actually managed to get there on the very first try but I hadn't attached docking ports the correct way. Got it the second time.
Like many others, I lost my account in April 2013.
Actually, when 0.18 came out I docked on my very first try.
The "closest approach" was good. I waited until my target was on the other continent to the left, launched a standard launch, and waited till it got closest. Once there, I did an insane burn thanks to the target mode, and then burned toward it, waited, retro burn, and docked.
And no, I could not dock in 0.17 with ORDA. Only 0.18.
Yeah, I''ve been around.