Docking

[Thunhaho]

Hello, I have Kerbal Space Program on a mac computer.  I need help to make something dock, I've tried to do the training scenarios a lot of times but still confused. Can anyone please help?

[Vanamonde]

Thread moved to Gameplay Questions. 

What sort of difficulty are you experiencing? 

[Scarecrow]

You will need to be more specific with what exactly about docking you need help with.  Is it getting your craft to rendezvous that you are having problems with, or actually docking once they are in close proximity?  If the latter, perhaps you can better describe what you are doing and why it isn't working for you.  Also a picture of the craft you are trying to dock might help, as misplacement of RCS thrusters, often used during the docking process, can make your craft unstable and prone to moving around unintended axis, thus throwing your docking alignment out of sync.

[Plusck]

Couple of things:

- the "Mac" question shouldn't change anything. Unless you're using an antique (which is possible, given Mac build quality ;)) there should be no actual difference between versions of KSP.

- the "docking" tutorial is awful. Terrible. A crime. Shocking.

I may be exaggerating slightly but seriously, it is one of the most destructive tutorials out there because it forces you to do really idiotic things. It wasn't meant to be so idiotic, so if you start by trying to understand what it was actually trying to make you do (but ended up doing badly if you take it literally) I'm sure you'll have a Eureka moment and it'll all fall into place...

[James Kerman]

Greetings and welcome to the forum, @Thunhaho.  I had a lot of problems learning to dock with the tutorial until I came across @Snark's fantastic pictorial tutorial here:

https://web.archive.org/web/20151126132127/http://forum.kerbalspaceprogram.com/entries/3770-Illustrated-guide-to-docking

[Plusck]

Yep, just verified the immense idiocy of the "docking" tutorial and it is as bad as I remembered.

First it tells you to align planes while you are in a lower orbit. Therefore it is the worst possible time to change planes. Don't ever do that in real missions.

Next it tells you to get within 5km of a rendezvous. 5 km is awful. You should aim for 0.1km

Then it tells you to kill relative velocity at 5 km, using RCS... and then aim for your target using RCS with a maximum relative velocity of . I followed the tutorial literally and got myself in an orbit where I was 5km away but even with 10 m/s relative velocity I could never get within 100m of my target. Following the instructions would therefore never work.

Assuming some intelligence, I used up a huge amount of monoprop killing relative velocity and then aiming for the target again. Again, the tutorial doesn't explain anything and if I didn't know what was happening, I'd be totally lost circling about the target at around 100-200m with rapidly dwindling monoprop supplies...

[James Kerman]

1 hour ago, Plusck said:

I'd be totally lost circling about the target at around 100-200m with rapidly dwindling monoprop supplies...

Exactly my experience.

[Cheif Operations Director]

Ok here is the readers digest version launch a rocket and put Apoapsis at target altitude for example if I have a craft at 100,000 meters peri and apo put your new craft that your launching at a 100,000 meter apo then at apo circulate your orbit so you have a 100,000 meter apoapsis and periapsis or pretty close not determine the postion of your craft remember both crafts trying to dock should have the same orbital peramiters and this includes inclination, use the green nodes after you set your target craft as target, once you get 0.1 for positive or negitve inclination relative to your target find if your are in front or behind the craft you want to dock with

if you are in front do a small burn prograde a periapsis or apoapsis this just be small maby a 7 seconds tops but it really depends on your thrust. Now timewarp until the orange markers have a distance of 70 miles or less. If your orange markers move away from each other your doing it wrong once at a distance of 70 miles switch to target mode on the gimble now wait until your target M/S begins to increase with orbits it might slowly increase but it the terms of docking when it starts really increasing be aware you need to go to the next step... 

if you are in front do a small burn retrograde a periapsis or apoapsis this just be small maby a 7 seconds tops but it really depends on your thrust. Now timewarp until the orange markers have a distance of 70 miles or less. If your orange markers move away from each other your doing it wrong once at a distance of 70 miles switch to target mode on the gimble now wait until your target M/S begins to increase with orbits it might slowly increase but it the terms of docking when it starts really increasing be aware you need to go to the next step... 

Use map view too your advantage now make sure you have target mode pulled up on gimble and burn on the retrograde until it is 0 m/s then burn toward your target it should be pink then at your desired distance to target burn retrograde and repeat until within 100 meters.

Finally select your desired docking port and make it your target so you can better maneuver Now switch to docking mode enable SAS and RCS pulse jets and alight with the docking port don't rush stabilize at 0m/s and then begin your docking procedure align your craft hoizontial and then kill your horizontal velocity so you are stationary then alight vertically then kill vertical velocity now go into 

Note: Make sure your direction marker (where your front is faced) is on the target marker (so your two ports are in line here is a diagram no pulse forward and keep the docking port in line and it SHOULD Auto dock. 

Docking object 1--->           <---Docking Object 2

Edited December 10, 2017 by Cheif Operations Director

[purpleivan]

One little tip. If you want to practice docking without the whole rendezvous part, send up two docked vehicles in the same launch. That might seem obvious but it's an option that can easily be overlooked.

Once in orbit, undock the vehicle that you'll be controlling and move away from the other, then maneuver back and re-dock. Do this as many times as you have mono-propellant for. Might as well add a mono-propellant tank(s) to supplement that in the capsule to give you plenty of opportunity. Each time you undock, move to greater distances before returning to dock as well as bigger differences in attitude between the two vehicles.

This was the way I did it when I first started playing the game, following rough recreation of Apollo missions. So in in my "Apollo 9" mission I was made multiple dockings of my CSM and LEM vehicles in Kerbin orbit, before heading off to the Mun for the real thing.

Like with most things, practice is the key.

Edited December 10, 2017 by purpleivan

[Spricigo]

I will let @NecroBones explain that for you.

 

[Rocket In My Pocket]

Don't think anyone mentioned it yet but the debug menu (Alt+F12) will let you not only place a craft in orbit, but also teleport it to another craft via the "rendezvous" button.

This is a fantastic shortcut for testing designs or practicing docking.

[wumpus]

2 hours ago, Rocket In My Pocket said:

Don't think anyone mentioned it yet but the debug menu (Alt+F12) will let you not only place a craft in orbit, but also teleport it to another craft via the "rendezvous" button.

This is a fantastic shortcut for testing designs or practicing docking.

I would have to point out that I found the rendezvous part more difficult that pure docking (at least once you get the hang of RCS).  In career mode kerbal rescue missions give great practice in rendezvous (you can't really dock, but getting as close as possible helps to find the rescue ship once you've taken control of the "lost" kerbal.

- check for an empty seat before takeoff.  Jeb loves to grab the seat whether or not he was placed there.  If you even touch the capsule after taking him out he might sneak back in (especially after loading a save).  There is at least one mod out there to prevent this.

[Rocket In My Pocket]

12 minutes ago, wumpus said:

I would have to point out that I found the rendezvous part more difficult that pure docking (at least once you get the hang of RCS).  In career mode kerbal rescue missions give great practice in rendezvous (you can't really dock, but getting as close as possible helps to find the rescue ship once you've taken control of the "lost" kerbal.

Oh, I agree completely; I've always found actual docking to be easy as pie, you're just placing one object next to another in empty space with full freedom of movement. There is nothing to dodge, or shoot, or avoid...you just move your ship over to the other one, I'm honestly confused why so many seem to struggle with it.

It was the rendezvous itself and wrapping my head around the orbital mechanics that was the hardest part for me as well. The ol' Mk1 eyeball takes care of the rest.

However it seems many find the actual docking bit to be the difficult portion for whatever reason.

[Pwnstarr]

Which step are you having trouble with? 

The tutorial isn't as bad as Plusck makes it seem. There are a couple areas where the tutorial could use improvement, but otherwise I got within 3 km following the instructions no problem.

Anytime you start moving away from the ship, burn retrograde (green X) to cancel relative velocity, then burn Pro-Target (pink circle) to move towards the ship again. You can use main engines or RCS as the tutorial says. There are more optimal ways to do this, but it works. Hit the brakes, then reorient and thrust. 

The tutorial says to use the Chase camera for final approach, this is wrong AFAIK. The Locked camera in recent versions of KSP is what the chase camera used to be, it is much easier to line up the ship correctly in Locked. 

Use SAS to keep your ship pointed toward Pro-Target (pink circle) while you use lateral thrusters to close in and dock. 

[Spricigo]

8 minutes ago, Pwnstarr said:

The tutorial says to use the Chase camera for final approach, this is wrong AFAIK. 

I consider the correct way to be using the flight instruments (e.g. navball). Unfortunately the instrument for alignment is missing in stock.

[Pwnstarr]

3 hours ago, Spricigo said:

I consider the correct way to be using the flight instruments (e.g. navball). Unfortunately the instrument for alignment is missing in stock.

Agreed.

This is what phasing and docking look like to me these days  

Edited December 10, 2017 by Pwnstarr

[Corona688]

My rules for intercepts and docking -- all homegrown hayseed nonsense -- are as follows:

Fine-Tuning Intercepts:

• When you're headed directly for a target, the prograde reticle will be inside the target reticle, and the retrograde reticle will be anti-target.
• When you're headed directly away from a target, the prograde reticle will be in the anti-target reticle and the retrograde will be in the target.

So, to alter course directly towards a target means moving the retrograde reticle towards the anti-target reticle.

• The prograde reticle gets "sucked towards" forward thrust.
• The retrograde reticle gets "pushed away" from forward thrust.

So, to make your intercept closer while slowing down at the same time, aim a little off from retrograde, in a manner that pushes the retograde reticle towards the anti-target.  This is best done within a minute or two of intercept for highest accuracy.

Done right, it's possible to zero in on your target and reach orbit at the same time.  The navball will show you the way.  Being in the same place as your target at nearly the same speed means nearly the same orbit, after all.

Docking:

Once you're close enough to worry about hitting your target, the target reticles themselves will move around!

• The prograde reticle "pushes" the target reticle away from it.
• The retrograde reticle "pulls" the target reticle towards it.

So to dock you must do three things:

1. Match the angle of your target (have to eyeball this, don't know a good way to do this on navball)
2. Push the target reticle into the center of the navball with the prograde reticle
3. Keep the prograde reticle near the target

What this means in "real-world" terms is 1) Point the same direction as their docking port, 2) Line up with the target, 3) Move directly towards the target

The target will want to "shimmy away" when you get real close, you just have to keep on it by moving the prograde reticle around to push the taret back into the center.

Edited December 12, 2017 by Corona688

[StrandedonEarth]

My first few times docking were horrible, trying to align and line-up everything by eye with unbalanced RCS. I found a docking alignment indicator mod and learned how to fly the navball and never looked back. The best advice I can give is:

[Corona688]

15 hours ago, StrandedonEarth said:

My first few times docking were horrible, trying to align and line-up everything by eye with unbalanced RCS.

Probably preaching to the choir, but the instant the game introduced RCS, I already wanted the ability to set RCS thrusters linear-motion-only.  You can now do this under a thruster's advanced tweakables - disable yaw, pitch, roll.  You can even do this in flight if you have to, and it helps so much.  No more insane rocking.  No more wasted fuel.

[StrandedonEarth]

8 minutes ago, Corona688 said:

Probably preaching to the choir, but the instant the game introduced RCS, I already wanted the ability to set RCS thrusters linear-motion-only.  You can now do this under a thruster's advanced tweakables - disable yaw, pitch, roll.  You can even do this in flight if you have to, and it helps so much.  No more insane rocking.  No more wasted fuel.

Yes, being able to disable RCS for rotation was a godsend (Squadsend?). But using RCS to turn large ships is useful if you don’t want to time the turn with a calendar. 

[Rocket In My Pocket]

Agreed, @Corona688 and @StrandedonEarth

I still remember the days of laboriously hitting "R" every time before I did any rotations, then hitting "R" again to do some translating...then again, ...and again, ......and again....

Thank Jeb for advanced tweakables!

[Nicias]

Caps-lock for balanced translation and Navball Docking Alignment Indicator FTW.

[Tyko]

2 build tips for your ship that help

1. Make sure your RCS thrusters are situated around the center of mass of the ship that will be docking. bring up the center of mass indicator in the VAB and use that as a guide. Don't forget to consider how much fuel you'll likely have. Estimate how much fuel you'll have left and temporarily empty the tanks to that level to get a better COM estimate.
2. on the RCS thrusters turn off rotation, pitch and yaw thrust so that the thrusters only activate for translation (Up/Down, Forward/Backward, Right/Left)- This is in the right click menu for the RCS, I don't recall the name of the setting in the right click menu...sorry, but it's pretty obvious.