Docking issues

[The Space Core]

Alright after playing for an ungodly 467 hours I still have absolutely no idea how to dock. I can get an intersect node Ive even passed close to the craft I've wanted to dock with, but all the guides I've seem say to turn target and burn retrograde in order to kill the relative velocity to the craft. But this always messes with my intersect node to the point where they're almost nowhere near each other.

Im asking now because Im constructing my first space probe to Duna, Ive already sent a science module with a command pod into a nice circular orbit. Lastly my docking controls don't work. When I click on docking shift and control won't send my craft further.

Thanks for responding.

~The space core.

Edited October 25, 2015 by The Space Core

[celem]

Well you seem to have the theory correct.

1. You make a burn somewhere and get an intersect node, you wait a bit and you are passing close by to the target.

2. You set the navball to target mode, you then burn retrograde to target, thats a purple icon...just incase you are burning on the green retrograde for this step. If you are doing this correctly then the speed displayed by your navball which is in target mode should decrease to more or less zero. If it falls, but then starts climbing again before hitting zero or close to it then you are definitely burning on the wrong indicator.

To be very clear, once you set a target in map view two purple icons appear on the navball, these are used for exactly this situation, one is target prograde, the other target retrograde. In general watch that target speed display, it should never rise while you perform this step.

3. Once your relative velocity is more or less zero then the intersect marks on map view stop meaning very much, they just describe closest approach as the 2 ships drift slightly closer together and/or further apart. As long as your target speed is around zero then you will track the target and remain more or less where you are relative to it.

4. There are a few edge cases to watch for, attempting to intercept craft in very low orbits is dangerous, you might get your close approach of only 5km or whatever, but its 5km vertical, the target was at 72x72 and your approaching craft is gonna hit the atmosphere, this obviously wrecks everything and happens to me a lot. I prefer not to dock below 80km for this very reason, so that a sub-10km closest approach is always gonna be vacuum.

[Scarecrow88]

What you are doing when you burn retrograde in target mode is more closely matching the two orbits. Once you have the relative speed at zero, or close to zero, if you are still some distance away from your target vessel you should then burn prograde towards your target, but not too fast or you will just fly past when you get even closer. In all likelihood this will indeed move your intersect point around your orbit, but it should make the intersect distance between your two craft a lot closer.

As you get closer to your target you may find that the prograde marker is drifting away from your target marker, in which case you can just repeat the above process as required. There is a more efficient way of doing this, but this method should serve you until you become more used to the rendezvous process.

[The Space Core]

Ah alright, but what do you think is up with my docking controls?

[celem]

that one seems puzzling, however I've never actually used docking mode so have no clue whats going down there.

Its certainly possible to do without it if you play about a bit with the RCS to figure out what button has which effect on the navball indicators. If not in docking mode then im pretty sure 'h' and 'j' are your forward/reverse thrusts

[A35K]

Docking controls aren't necessary. In fact, I've never used them. What I did was to change the RCS controls to I for translate forward, K for backwards, L for left, J for right, Right Shift for up, and Right Ctrl for down.

[Snark]

So docking generally involves the following major phases:

1. Intercept. This is the part where you use maneuver nodes to arrange for your ship and the target to be in the same place at the same time, or at least as close as possible. Careful fiddling with the maneuver node will generally get you an intercept within a kilometer or so.

2. Fine tuning the intercept. This involves making small burns as you approach the target, in the last few kilometers, so that your closest intercept is zeroed in to a few dozen meters (from the kilometer-or-so you got in step 1). This involves close observation of the navball and light touches on the throttle.

3. Kill relative velocity to target, right when you're at your closest approach. Also a navball-and-throttle operation. You're now parked right next to the target, just a few meters away.

4. Actually dock. This involves eyeballing docking port alignments in the camera view (unless you have a mod installed to show docking alignment on the navball, which is a big convenience). This is where you use your RCS thrusters to jockey for position.

So, the above describes what the steps are without going into the nitty-gritty of how to do them. Which of these steps is where you're having difficulty?

(Relevant: Illustrated docking tutorial)

Docking controls aren't necessary. In fact, I've never used them. What I did was to change the RCS controls to I for translate forward, K for backwards, L for left, J for right, Right Shift for up, and Right Ctrl for down.

Agreed. I find the so-called "docking mode" to be confusing and useless. I never use it. Just use the default: WASD for ship rotation, HN+IJKL for RCS translation.

Edited October 24, 2015 by Snark

[The Space Core]

Alright!

I think I get it now.

TO clarify

Get the craft you want to dock on a nice relatively high orbit. Burn till you get an intersect node between 1 Km. Kill relative velocity At intercept. then dock.

My issue ( i think) was that I was trying to kill my velocity far from the intersect.

~THanks

[ForScience6686]

I gauge my burn based on velocity on regards to target. It is much easier if you rendezvous at the ap as both craft will be at there slowest velocity.

[uncle_jew]

4. Actually dock. This involves eyeballing docking port alignments in the camera view (unless you have a mod installed to show docking alignment on the navball, which is a big convenience). This is where you use your RCS thrusters to jockey for position.

I struggled a lot with this myself (I am a beginner). But then I discovered that the default navball (without any mods) has enough information for docking. I first orient my vessel so that its docking port approximately faces the target docking port. Then I click the target docking port (on the other vessel) and select is as target.

From now on, the target indicator in the navball (magenta dot surrounded by a dashed circle) shows the target docking port. And the prograde indicator shows my velocity relative to the target docking port.

Then, I hit 'H' to start slowly moving towards the target (it doesn't have to be a precise direction at all). During the whole docking, I am only looking at the navball - not at the camera view.

Then, I start using IJKL keys to make my vessel move precisely towards the target docking port. To do this, I press these keys until the prograde indicator on the navball exactly matches the target indicator on the navball. This means my relative velocity vector is pointed directly towards the target docking port. It's very easy - feels simply like moving the prograde indicator with arrow keys, not like actually maneuvering. As vessels come closer, the prograde indicator may slightly drift away from the target due to orbital mechanics - I immediately correct this using IJKL keys. As long as the the prograde indicator matches the target indicator - the docking ports are guaranteed to come into contact regardless of how it looks in the camera view.

This method gave me a 100% docking success rate and lowered my RCS fuel consumption during docking by a factor of ~5. And it allows me to relax during the last 2-3 meters and simply enjoy the docking from the camera view without having to control anything.

It's a pity KSP docking ports have no optical alignment indicator (like real ones) - this would have allowed matching the exact docking direction too.

Edited October 28, 2015 by uncle_jew

[CrashTestDanny]

Alright after playing for an ungodly 467 hours I still have absolutely no idea how to dock. I can get an intersect node Ive even passed close to the craft I've wanted to dock with, but all the guides I've seem say to turn target and burn retrograde in order to kill the relative velocity to the craft. But this always messes with my intersect node to the point where they're almost nowhere near each other.

Im asking now because Im constructing my first space probe to Duna, Ive already sent a science module with a command pod into a nice circular orbit. Lastly my docking controls don't work. When I click on docking shift and control won't send my craft further.

Thanks for responding.

~The space core.

Allow me to highly recommend the in-game docking tutorial/scenario led by Gene Kerman. He walks you through a no-nonsense seat-of-the-pants docking doing little more than looking out the window. It took me about 40 minutes to get it right, but it was 40 minutes well spent. Gene was very helpful and patient with my noobiness and he had good advice and helpful tricks that I can still use after having gone through his tutorial once... and now I'm applying what he taught me to docking 7.5m SpaceY tanks for a small LKO 100 fuel depot...

Danny

- - - Updated - - -

I struggled a lot with this myself (I am a beginner). But then I discovered that the default navball (without any mods) has enough information for docking. I first orient my vessel so that its docking port approximately faces the target docking port. Then I click the target docking port (on the other vessel) and select is as target.

From now on, the target indicator in the navball (magenta dot surrounded by a dashed circle) shows the target docking port. And the prograde indicator shows my velocity relative to the target docking port.

Then, I hit 'H' to start slowly moving towards the target (it doesn't have to be a precise direction at all). During the whole docking, I am only looking at the navball - not at the camera view.

Then, I start using IJKL keys to make my vessel move precisely towards the target docking port. To do this, I press these keys until the prograde indicator on the navball exactly matches the target indicator on the navball. This means my relative velocity vector is pointed directly towards the target docking port. It's very easy - feels simply like moving the prograde indicator with arrow keys, not like actually maneuvering. As vessels come closer, the prograde indicator may slightly drift away from the target due to orbital mechanics - I immediately correct this using IJKL keys. As long as the the prograde indicator matches the target indicator - the docking ports are guaranteed to come into contact regardless of how it looks in the camera view.

This method gave me a 100% docking success rate and lowered my RCS fuel consumption during docking by a factor of ~5. And it allows me to relax during the last 2-3 meters and simply enjoy the docking from the camera view without having to control anything.

It's a pity KSP docking ports have no optical alignment indicator (like real ones) - this would have allowed matching the exact docking direction too.

Don't forget to right click on the docking port on the ship you are flying and select "Control From Here". That will correct the nav ball orientation so your keys match what's being displayed on the nav ball. If you are controlling from some other location you will have to mentally adjust, which is tough (for me anyhow).

BTW - there are mods that add alignment indicators to ports.

Danny

[manaiaK]

Allow me to highly recommend the in-game docking tutorial/scenario led by Gene Kerman.

I remember trying that a few times early on, but my PC got laggier and laggier as I progressed through the tutorial, and it froze up altogether just as Gene was getting to the important bits. Maybe I should see whether that still happens, and log a bug if so.

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Update: Just tried it out again, and it's fine. I still suck at docking without Docking Port Alignment Indicator (DPAI), though.

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Also, in a game, I had a situation where one docking port had no "magnetism", so it was more of a gentle battering ram than anything. Six docking attempts later ... let's say I was glad I'd added a few other docking ports.

One final point about docking for the OP: if it looks like you're docked, but your two craft don't merge into one (you'll know when this happens): turn off SAS. This has given me a few minutes' confusion more than once.

Edited October 29, 2015 by manaiaK
Update.