Orbital docking, closing the gap

[O-Doc]

I understand this game is under development but I wanted to ask if this docking will ever get fixed, obviously there must be some bug when you dock bang in the middle and it just bounces off, once is understandable but 42 times is a p*ss take.

Do you have electricity to power your docking ports?

[impyre]

I understand this game is under development but I wanted to ask if this docking will ever get fixed, obviously there must be some bug when you dock bang in the middle and it just bounces off, once is understandable but 42 times is a p*ss take.

The magnetic docking ports are quite weak... and rightly so when you consider how heavy these vessels are. If we're talking realism here, magnetic docking alone would never work, you'd need something that will physically lock in place. That said, the optimal approach speed is .2 or .3m/s... or as close to zero as you can get it. Consider that the key thing here is momentum... the magnetic docking ports have a limited range over which they can act, and a limited force/torque they can exert... which means they can do limited work to negate momentum. As momentum is speed*mass, you can see how those numbers can get big fast with a ship that weighs several thousand kilograms (at least).

There are two "fast" ways to dock: Get a speed near .1 or .2m/s, and use phys warp to close the distance from 8-10m until about 1-2m (which could prove dangerous)... OR approach at .8-1m/s and then slow down as you get closer(which could also prove dangerous). Which approach you use may depend in part on your ship design. If you have too little or too much thrust, trying to adjust velocities at the last second is probably unwise, so physwarp may be a better option; however, if your ship has optimal thrust for its weight, adjusting velocity at the same time may offer better control. Bear in mind that you can use "fine control" mode to help keep you from over-correcting if you have "too much" thrust.

EDIT: Another thing to keep in mind is that due to moment of inertia, torques applied at odd angles have much less effect on longer objects (namely, rockets). So docking ports will be much less effective if the angle isn't *exact*. Combining this with high-speed approaches often leads to failed attempts. I'd recommend some docking port alignment indicator mod. There are two that I've used, one which uses the navball and one which uses a popup window. Both are excellent and helpful for docking, I'll never dock without at least one of them again. This allows you to get your alignment perfect, then coast in at the desired velocity.

Edited August 4, 2014 by impyre

[fuzzdemon]

fuzzdemon - What's your velocity/speed when your docking ports 'bang' together? I find all I need do is very slowly come to just within touching, and the dock ports attract and pull together (even with with very large ships).

Yes very slowly, 1m/s and less. I have 2 large ships and using the medium size ports so even though it is hard I have them lined up perfectly and just kissing them together, but they just sit there doing nothing, needs fixing badly.

Do you have electricity to power your docking ports?

Yes

The magnetic docking ports are quite weak... and rightly so when you consider how heavy these vessels are. If we're talking realism here, magnetic docking alone would never work, you'd need something that will physically lock in place. That said, the optimal approach speed is .2 or .3m/s... or as close to zero as you can get it. Consider that the key thing here is momentum... the magnetic docking ports have a limited range over which they can act, and a limited force/torque they can exert... which means they can do limited work to negate momentum. As momentum is speed*mass, you can see how those numbers can get big fast with a ship that weighs several thousand kilograms (at least).

There are two "fast" ways to dock: Get a speed near .1 or .2m/s, and use phys warp to close the distance from 8-10m until about 1-2m (which could prove dangerous)... OR approach at .8-1m/s and then slow down as you get closer(which could also prove dangerous). Which approach you use may depend in part on your ship design. If you have too little or too much thrust, trying to adjust velocities at the last second is probably unwise, so physwarp may be a better option; however, if your ship has optimal thrust for its weight, adjusting velocity at the same time may offer better control. Bear in mind that you can use "fine control" mode to help keep you from over-correcting if you have "too much" thrust.

EDIT: Another thing to keep in mind is that due to moment of inertia, torques applied at odd angles have much less effect on longer objects (namely, rockets). So docking ports will be much less effective if the angle isn't *exact*. Combining this with high-speed approaches often leads to failed attempts. I'd recommend some docking port alignment indicator mod. There are two that I've used, one which uses the navball and one which uses a popup window. Both are excellent and helpful for docking, I'll never dock without at least one of them again. This allows you to get your alignment perfect, then coast in at the desired velocity.

Yes ive done all that, I used to play Orbiter and learned all that there, I just think its too fussy on this game, you want to just dock and get on with it, no wonder everyones using auto dock and grappling arms, shouldnt need to do that. Its in development though so I get that, but at the moment im stuck and cant play it until they fix it, i imagine a lot of people has dumped this game because of this bug.

Funny thing is in Orbiter it was too easy to dock and I wasnt satisfied that it was so forgiving so I would undock again and pretend I had to be perfect lol

Edited August 4, 2014 by fuzzdemon

[MockKnizzle]

Fuzzdemon, I suspect you are either doing something wrong in the construction of your crafts or experiencing a bug. Docking ports require no power, and the magnetism is very forgiving. Myself and many others are able to use docking ports with no issues. Please post some pictures of your craft so we can check it out.

[Pecan]

Yes very slowly, 1m/s and less. I have 2 large ships and using the medium size ports so even though it is hard I have them lined up perfectly and just kissing them together, but they just sit there doing nothing, needs fixing badly.

That's the second time you've blamed KSP for your failure.

you want to just dock and get on with it

Which might be because you're not taking it carefully enough.

no wonder everyones using auto dock and grappling arms

Because you see the rest of us aren't using 'other means' in general. We can dock quite nicely, thank you.

im stuck and cant play it until they fix it

Third time, there is nothing to fix. It works perfectly well as is and as intended.

I imagine a lot of people has dumped this game because of this bug.

Fourth time - there is no bug with the docking system (undocking has had its issues). I don't know of anyone who has quit KSP because they don't like the way docking works but it does certainly work. I can understand that many people might not have the patience or ability to learn how to dock and might leave in frustration.

It's a difficult system that you need to put practice into learning, but there's no bug in it, as such, and so it doesn't need fixing.

[Seret]

I just think its too fussy on this game, you want to just dock and get on with it, no wonder everyones using auto dock and grappling arms, shouldnt need to do that.

You don't. I suspect you've either done something like stick one of the docking ports on backwards, or (much less likely) you've found a bug. The only thing I've found that routinely stops docking ports from attaching is SAS. With it on the reaction wheels and docking port magnetism can end up fighting each other. Just turn SAS off and it should click together nicely.

[micha]

Yes very slowly, 1m/s and less.

Not 1m/s, try final approach (last couple of meters) at <0.3m/s, as others have said. Even 0.5m/s is too fast depending on size of ships, relative speeds, and alignment.

Also, definitely try using a docking indicator mod. I use the NavyFish one, it's excellent. I've not ever tried docking without it so have no idea how easy/hard it would be to align the ships for the docking ports to grip, but with it I've performed at least a dozen dockings, each one without a problem.

[Sirrobert]

And thanks for the tips on docking, all. After a lot of effort, I did manage to dock. I got within 2 kilometers, killed my velocity. Closed the gap with the RCS H key, mostly. Sometimes with a little regular thrust. Then I kept killing my velocity. I'm sure I was doing it pretty inefficiently, and I was running on fumes. So I switched to the fuel tanker, turned on its auto-grabber, and did the same from that end. Eventually, I did manage to dock.

Transferring fuel is amazingly satisfying. I managed to fill up my main tank plus the two boosters I never jettisoned.

Then I separated the ships, and moved the tanker to a safe distance.

Just one problem.....my beautifully-refueled ship, I'm just drifting, waiting for the optimum place to begin my burn....

So.....I started time-warp to speed things up a bit....

...and....and.....my ship instantly explodes?! Why?!

Congratulations on your docking!

The next time will be twice as easy, I promise you.

As for exploding, not a clue from just that info, but it's probably a bug. Did you quicksave? (if you didn't, extra kudos for docking the first time in 1 go)

Yes very slowly, 1m/s and less. I have 2 large ships and using the medium size ports so even though it is hard I have them lined up perfectly and just kissing them together, but they just sit there doing nothing, needs fixing badly

So why don't you show us some pictures to show us this bug of yours?

Than we'll be able to identify the problem ourselves, and everyone will believe you

[Algomeysa]

Algomeysa, before you time-warped did you turn SAS off? I've had a few ships which would develop wobble (space station too) with SAS left on. There's a few posts here on the forums about that. Also, are you sure your craft didn't collide with your other ship?... the one you thought you had moved safely out of they way? Been there and done that too.

thanks, LordFerret. This time I made sure to blast the tanker into a completely different orbit, and then I made sure SAS was off, and now I seem to be able to timewarp without the ship flying apart. Whew ---- if after all that work, it turned out that docking with a refueling tanker made my ship structurally unsound, I was going to be very very annoyed...

[Seret]

Also, definitely try using a docking indicator mod. I use the NavyFish one, it's excellent. I've not ever tried docking without it so have no idea how easy/hard it would be

Not hard at all IMO. I've never bothered with docking mods, you can just eyeball it. Just keep the speed low and change the camera angle a couple of times to make sure everything is lined up. It doesn't need to be perfect, they'll align themselves when you get close enough.

Changing the camera to chase view helps hugely though.

[Sirrobert]

thanks, LordFerret. This time I made sure to blast the tanker into a completely different orbit, and then I made sure SAS was off, and now I seem to be able to timewarp without the ship flying apart. Whew ---- if after all that work, it turned out that docking with a refueling tanker made my ship structurally unsound, I was going to be very very annoyed...

It's probably just a bug though. There is no physics when you're timewarping, so it's even possible for ships to float through eachother (they'll explode if you stop timewarp at that point though)

You don't really need to bother about a different orbit either. Just make sure you give it a kick with RCS. Once it starts drifiting away at like 1m/s, it'll keep drifiting away and you'll be good

[fuzzdemon]

Fuzzdemon, I suspect you are either doing something wrong in the construction of your crafts or experiencing a bug. Docking ports require no power, and the magnetism is very forgiving. Myself and many others are able to use docking ports with no issues. Please post some pictures of your craft so we can check it out.

I got rid of the game today its too buggy, I might buy it again when they fix the bug.

That's the second time you've blamed KSP for your failure.

Which might be because you're not taking it carefully enough.

Because you see the rest of us aren't using 'other means' in general. We can dock quite nicely, thank you.

Third time, there is nothing to fix. It works perfectly well as is and as intended.

Fourth time - there is no bug with the docking system (undocking has had its issues). I don't know of anyone who has quit KSP because they don't like the way docking works but it does certainly work. I can understand that many people might not have the patience or ability to learn how to dock and might leave in frustration.

It's a difficult system that you need to put practice into learning, but there's no bug in it, as such, and so it doesn't need fixing.

You obviously haven't challenged yourself enough or you always use auto dock like everyone else, of course docking works but not as it should work, its easy to dock sometimes and it locks almost instantly but its too temperamental, if you watch footage of the space shuttle docking with ISS it NEVER sways around for 10 minutes before locking. Ive been docking in games ever since docking in games was invented so I dont need a lecture on how to practice.

[Seret]

its easy to dock sometimes and it locks almost instantly but its too temperamental

It's really not. As people have said there was an undocking bug, IIRC they've squashed that. But docking works absolutely fine.

[fuzzdemon]

It's really not. As people have said there was an undocking bug, IIRC they've squashed that. But docking works absolutely fine.

Congratulations but im not docking 2 little modules im docking 2 large rockets, pinpoint accuracy but 100% bugs.

[Laie]

Congratulations but im not docking 2 little modules im docking 2 large rockets, pinpoint accuracy but 100% bugs.

Pics or you're a liar.

[Sirrobert]

Congratulations but im not docking 2 little modules im docking 2 large rockets, pinpoint accuracy but 100% bugs.

You still haven't provided us with a SINGLE bit of information regarding this 'bug', other than 'it's buggy'

How the hell do you expect people to help you if you don't tell them anything?

Show some screenshots. Sounds to me like you're using the SR docking ports, and mounted one of them upside down. It's a common mistake

[pellinor]

"Large rockets" at "1m/s or less"? Isn't this a bit fast? I'm used to docking large things at 0.1 or 0.2 m/s, and never had problems other than from my own mistakes.

[micha]

... it NEVER sways around for 10 minutes before locking. ...

Do you turn SAS off as soon as the magnets start pulling the ships together (if not before)? If not, the SAS module fights the aligning force of the docking ports.

[fuzzdemon]

Pics or you're a liar.

You still haven't provided us with a SINGLE bit of information regarding this 'bug', other than 'it's buggy'

How the hell do you expect people to help you if you don't tell them anything?

Show some screenshots. Sounds to me like you're using the SR docking ports, and mounted one of them upside down. It's a common mistake

Thats because I gave up and uninstalled the game before people asked for pics, this is the only screenshot I have of the target docking ship that I took for reference yesterday when designing the 2nd rocket, as you can see I have no issues with docking normally, although i still think its too temperamental, but docking with the small ports on the side is just not happening, ive managed to do it once only but it was such a ball ache I gave up on it. I refuse to give in like everyone else and use auto docking tools or hacking files when I find a limitation in the game.

http://i64.photobucket.com/albums/h165/Hail_Odin/rd_zpsa04501ad.jpg

[Grover]

You guys accept 10km as an adequate target intercept? Most of the time im getting it to 400-500m, if it were more than 1km id consider myself really sloppy

[fuzzdemon]

Do you turn SAS off as soon as the magnets start pulling the ships together (if not before)? If not, the SAS module fights the aligning force of the docking ports.

Yes I only use SAS when performing burns, I dont need it when docking I just eyeball the stars to judge movement of the rocket works well and obviously less fuel used.

You guys accept 10km as an adequate target intercept? Most of the time im getting it to 400-500m, if it were more than 1km id consider myself really sloppy

I think even more than 10km is adequate but like you say sloppy.

Edited August 4, 2014 by Rich

[Algomeysa]

so say I'm in Kerbin orbit, and I want to get in solar orbit ---- but clockwise, that is, opposite the direction most of the planets are traveling. What should be my approach?

And speaking of solar orbits.... when you're in orbits that last hundreds of days, burning exactly at apoapsis probably isn't that important, it's more forgiving of mistakes. Is going at full throttle a mistake? Should I be starting earlier and just going at a fraction of full throttle, is that going to be more fuel-conserving?

[Seret]

I refuse to give in like everyone else and use auto docking tools or hacking files when I find a limitation in the game.

I agree. I disagree that most people are using them. Mods like Mechjeb actually do a really poor job of docking, most people don't use them for long, if at all. Keep practising, you'll get the hang of it.

[Kerbart]

Thats because I gave up and uninstalled the game before people asked for pics, this is the only screenshot I have of the target docking ship that I took for reference yesterday when designing the 2nd rocket, as you can see I have no issues with docking normally, although i still think its too temperamental, but docking with the small ports on the side is just not happening, ive managed to do it once only but it was such a ball ache I gave up on it. I refuse to give in like everyone else and use auto docking tools or hacking files when I find a limitation in the game

Well, we're getting a bit more info now. Did you set the docking port as target, and did you use "control from here" on the other one? What kind of docking ports? If they were the inline ones, did you actually open the doors to activate them?

As mentioned before, docking is a process where virtually no one has reported a bug. Ever. Undocking, yes. And I doubt there are that many people that use auto docking tools (the only one I know of is MechJeb and it does an absolutely horrible job at it) or hacking (a total headache, only for special cases; docking manually is much, much easier) in the first place.

I'm glad the Wright brothers, Goddard and Von Braun didn't give up so quickly; we'd still be stuck to the ground.

[fuzzdemon]

Well, we're getting a bit more info now. Did you set the docking port as target, and did you use "control from here" on the other one? What kind of docking ports? If they were the inline ones, did you actually open the doors to activate them?

As mentioned before, docking is a process where virtually no one has reported a bug. Ever. Undocking, yes. And I doubt there are that many people that use auto docking tools (the only one I know of is MechJeb and it does an absolutely horrible job at it) or hacking (a total headache, only for special cases; docking manually is much, much easier) in the first place.

I'm glad the Wright brothers, Goddard and Von Braun didn't give up so quickly; we'd still be stuck to the ground.

Yes ive done all that, trust me im not a noob, ive used many space sims and docked millions of times with my eyes closed. See the pic in the my last post above, im trying to dock with the small port on the side, if this small port is on a small rocket its easy, when its on a large rocket is almost impossible, I managed to do it once only and it took about 5 minutes to lock even though its perfectly central and lined up, whether you consider this an issue or normal its not realistic.

I agree. I disagree that most people are using them. Mods like Mechjeb actually do a really poor job of docking, most people don't use them for long, if at all. Keep practising, you'll get the hang of it.

Ive given up until it gets fixed. I understand you think of me as a noob that needs practice but its not the reason why they arnt locking, if that was the reason I wouldnt waste everyones time.

"Large rockets" at "1m/s or less"? Isn't this a bit fast? I'm used to docking large things at 0.1 or 0.2 m/s, and never had problems other than from my own mistakes.

I can guarantee you wouldn't be able to dock these rockets within a realistic time scale, of course its possible eventually but it shouldn't be this unrealistically hard, thats my point, im assuming that nobody here has ever seen footage of the space shuttle docking with ISS and how inaccurate and fast the docking is yet its designed to be forgiving and lock, it certainly never ever bounces off or refuses to lock when they are face to face. Im not having a go at the makers of the game its a fantastic game and in development but I do hope they look into this issue and make the docking more realistic, all im asking for is if your perfectly lined up and your approach speed is 0.0001m/s you should get an instant lock every single time on any rocket of any size.

Edited August 4, 2014 by Rich