djr5899

Any veteran tips for the docking inept?

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Before one can learn how to dock, one must master the rendezvous.

once you're close to your target, set the camera to fixed mode by pressing V to cycle the camera modes, then you can use RCS to manuver your vessel into position.

once you learned how to dock normally, you can mount a docking port on the SIDE of your vessel instead of top/bottom and learn how to dock using only the main engines and no RCS or monopropellant.

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I'm going to assume you know how to rendezvous to within a kilometer. Here is how I dock. It is probably not the best way, but it works for me:

  1. When constructing the ship, temporarily remove all the parts that won't be there during docking (e.g. ascent stages, etc). Turn on the center of gravity marker. Place the multi-directional RCS ports in triangle or square configuration at both ends of the ship, at equal distance from the center of gravity! This is what ensures that you can actually use your RCS to move without spinning.
  2. Rendezvous with target to within 1 km (I generally aim for .5 or less, but whatever).
  3. Burn :retrograde: (with navball in "target" mode) to bring velocity to 0. This more or less "parks" you relative to your target.
  4. Burn toward the :targetpro: marker, then go ahead and flip the ship toward :retrograde: again and drift toward the target until you're within like a hundred meters or so.
  5. Burn :retrograde: until relative velocity is 0.
  6. Switch to target ship and rotate it so that the docking port is facing the incoming ship. Switch back to the incoming ship. Set the docking port on the target vessel as your target by right clicking it.
  7. Face in approximately the direction you'll need to be pointing when you dock.
    This may not necessarily be directly at the :targetpro: marker:
    docking_by_littlefiredragon-dcc7968.png
  8. Using RCS (I never use docking mode, just the HNJIKL keys), give the "forward" key just a tap or two - you don't want to move too fast just yet.
  9. Moving the camera to each dimension (e.g. looking straight down at the craft), adjust one dimension at a time using RCS. You can definitely use more than one tap of a key for this part. Once it lines up with the docking port in this dimension, cancel the velocity by RCS thrusting the opposite direction. So first you make sure you're aligned up and down, then you make sure you're aligned left and right.
  10. Turn off RCS and make any necessary adjustments to the rotation of the craft.
  11. Turn RCS back on and tap your forward key a few more times - don't approach too fast, but you can speed up a bit now that you're mostly in the right place.
  12. As you approach, keep moving your camera back and forth between side and top view so you can check that you're not drifting out of alignment in either dimension. Since you're aligned by this point, and you shouldn't be moving relative to the target in either direction, your :prograde: should be lined up with your :targetpro:. You can use this fact to help make sure you don't drift. If you start to drift, tap your RCS a couple times to cancel out the unwanted movement, then tap once in the opposite direction to cancel velocity once you're lined up again - this should line the markers up again. Keep doing this until you dock.
Edited by Ace in Space
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Hi all

 

I hardly count as a veteran, or an expert, but as someone who has managed a few rendezvous and dockings I can tell you that get it right comes down to three words: "Practice, practice and Practice". You are not going to get it right the first time or the second time or even the third time. Practice, practice, practice.... When you finally get it right it will be the biggest thrill of your KSP experience so far. 

 

Have fun, enjoy.

 

Regards

Orc

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8 hours ago, Supercheese said:

and lock SAS to Target.

This is only available to three-star pilots (or equivalent hardware).  In a career, you're generally near the top of the tech tree before you have this; in my current career, I have only three pilots with this rating, and they're all aboard the Duna flyby craft, Explorer VII, something like 120 days from their correction burn to set up their returning encounter with Kerbin.

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5 hours ago, Orc said:

Hi all

 

I hardly count as a veteran, or an expert, but as someone who has managed a few rendezvous and dockings I can tell you that get it right comes down to three words: "Practice, practice and Practice". You are not going to get it right the first time or the second time or even the third time. Practice, practice, practice.... When you finally get it right it will be the biggest thrill of your KSP experience so far. 

 

Have fun, enjoy.

 

Regards

Orc

This ^^

Try, fail, try again, fail, succeed, fail, fail, succeed, succeed, fail, succeed, succeed....

I tried for ages to get a good enough rendezvous, never mind a docking.  My first successful docking was when my son guided me through it, and it still took 6 hours!.  Now I don't shy away from it because I know I can do it when I want to and frequently build it in to my mission plans.

Once you get a feel for it failure becomes much less common and you can nearly always salvage a docking that would have been impossible for you at first.  And besides a failure just gives you another chance to practice with the rescue mission.  When it comes to docking there really is no substitute for experience.

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A great tip I wish I'd been given early on is, make sure both ships are aligned parallel with the north/south axis of the planet, i.e. the docking port of one ship should point due north (note: not point at the north pole), and the docking port of the other should point due south (note: not point at the south pole). Then use translation thrust and the stock aids on the navball to get the target in front of you, and just close in at a gentle speed. It makes it much easier to find your initial approach position and know your docking ports will be facing each other properly when you get close, not on some crazy impossible angle where you have to translate/rotate around to get there.

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Assuming both vessels have reaction wheels; come to a relative stop within 100-50m using the main engines, then control each from a docking port, target the docking port on the other, and turn them so they're as close to aligned as you can get. That's 90% of the battle, because now you just have to go "forwards" relative to one of the docking ports.

From this point, look at nothing except the navball. Unless you have an unusual brain, you won't process the arbitrary up/down/left/right nature of space, but the navball can. Left is left, up is up; just point at the target, nudge forward a little and use IJKL to slide the prograde marker around so it stays on top of the target marker. It doesn't matter if you come in at a slight angle, the magnets will take care of that as long as you're on target :) 

Use capslock for fine control. Tap the keys, don't press them. Slow, slow, slow, wins the docking race. If you're ever above 2m/s relative you need to slow down. Final contact should be below 0.5m/s to avoid bouncing.

Incidentally, this is exactly what MechJeb does not do with its automated docking, preferring to waste gallons of monoprop going around the far side of the target on RCS rather than getting there before beginning the manoeuvre. Most small vessels (e.g. Mun landers) can dock with just 1-2 units of MP used.

Also, this is not the most realistic docking method. The ISS does not rotate for approaching vessels. But this is KSP and you can choose to make your life hard or easy, and I choose easy :) 

Edited by eddiew
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14 hours ago, Ace in Space said:

As you approach, keep moving your camera back and forth between side and top view so you can check that you're not drifting out of alignment in either dimension. ...

Is there a mod or key-binding to switch views straight up/down/left/right on your vessel? Damn that would be handy for this.

Edited by Pthigrivi

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Don't even look at the camera view.  Your navball is far more precise in this kind of maneuver.

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3 hours ago, Capt. Hunt said:

Don't even look at the camera view.  Your navball is far more precise in this kind of maneuver.

^^ This.  If you can't dock with the nav ball, you can't dock reliably.  The only nav ball docking failures I've had in the past several attempts were trying to dock a Klaw on the pointy end of a nose cone (which, it turns out, the Klaw just won't do).

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51 minutes ago, Zeiss Ikon said:

^^ This.  If you can't dock with the nav ball, you can't dock reliably.  The only nav ball docking failures I've had in the past several attempts were trying to dock a Klaw on the pointy end of a nose cone (which, it turns out, the Klaw just won't do).

Depends what you're doing. If you're pulling up to radial ports on a station its nice to check that you're nice and perpendicular on the way in. 

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So I think at this point we can conclude that everybody has their own style of docking - try out a lot of methods and stick to whatever feels best for you.

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15 hours ago, Ace in Space said:

So I think at this point we can conclude that everybody has their own style of docking - try out a lot of methods and stick to whatever feels best for you.

We're phrasing things differently but Im surprised by how similarly most experienced players are doing this. Unless you're axially docking 2 small vessels and can SAS lock on target with both your breakdown above seems best. 

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So, first update is a successful dock between my Habitation module and my Science Module. Only took me about an hour to do some of the fine tuning, which I don't mind.  I didn't want this to be quick and painless, I just wanted the controls to respond the way I expected.  Learned a few things this time that made it click for me, including help from everyone's post.   

A few of the biggest things was that using SAS, RCS, and pointing at Target node wasn't the best approach.  I had one attempt where the magnets started to kick in and SAS started firing, flinging the ships back apart.  I had another time where I had cut SAS off, was only moving at 0.1 m/s, and for some reason the craft I was docking to kind of flipped out and sent itself into a spin.  I believe in that case, I may been coming in at a slight angle still, and with the craft attempting to dock being the bigger of the two (almost twice the size), when the magnets kicked in at an angle trying to swing the bigger craft magnetically into the docking port just had too much force.

I found that trying to line  up by the Target symbol once I got in close wasn't working very well, and that seemed to be sending me in at an angle under 20m apart.  Not sure why. My target vessel had been set on the normal inclination,  so I lined up the docking vessel to anti-normal, and that did the trick for the last few meters. That won't work for my next docking as my Fuel Station module is not going to be docked to an end point but a middle connector, so this should be interesting.

Thanks for the help.  We shall see if I get the Fuel Station module in with more ease, and the Escape pod (currently attached to my docked Science Module) moved over to the proper docking port. Fingers crossed.

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Don't forget "Control from here".  This will make the controls for any vessel react as if your pilot were inside the docking clamp.  This also works for any part that offers the option on a right click (generally, it's command parts and docking parts); it's very handy for doing things like pushing a LEM when it's docked to your CSM (or vice versa, if you're playing the Acapello 13 mission scenario in Making History).  You still have to remember to disable the rocket motor(s) pointed the wrong direction, but two vessels docked nose to nose need to agree on who's flying the setup...

Dock a few dozen times, and it'll start to feel natural.  I've seen Scott Manley (on video) launch from KSC and dock with a deorbiting craft -- less than ten minutes from engine start to get the docked pair back to a stable orbit (Pe above atmosphere).  Scott's probably docked thousands of times, but he makes it look so easy...

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I've also noticed the navball putting me somewhat low... It varies with orbital altitude and the parent body, but it's pretty reliably putting the velocity vector a little bit off on the dorsal/ventral axis. I've long since ignored the navball when making final approach, relying on NavyFish's excellent Docking Port Alignment Indicator and a healthy dose of practice.

 

Fun story to go with that, btw... was at an air museum that had a Gemini docking simulator game. Most people couldn't manage it when it was just one axis. I asked for full control, and the docent looked at me like I had grown a second head. Proceeded to nail the docking without issue, and the docent said he'd never seen anyone do that before. I told him: "Eh, I have some practice with this stuff. Controls may be a little different than what I'm used to, and certainly not as accurate as I'd like, but... *shrug*"

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So, the good news is after docking my Habitation module to my Science module earlier tonight, I also managed to launch a Fuel module, and get it docked as well. Definitely learning a lot more about how to counter-act forces and speed. Looking forward to continue to build onto my Space Station, and have regular fuel supply and Kerbal rotation flights.

I am still seeing one issue though that I cannot figure out, and I mentioned it above.   Attached to my Science Module was my Escape Pod, big enough to carry all the crew on the station.  I wanted to move this to a different connector dock, to essentially form an X shaped station.  Fairly simple you would figure.  Just undock the Escape Pod, move it around to the docking port, and dock it.  No major rendezvous to deal with.

My Escape Pod has 2 sets of RCS thrusters, but they were balanced for docking the Science Module to the station.  There is a bit of drift from true input.  When attempting to dock to the new Space Station port, I am hitting it at a slight angle.....maybe 15 degrees from true perpendicular.  As soon as my Escape Pod touches the docking port on the station, the magnet acts like they are like magnets, and it flings my escape pod away from the station in a nasty spin.  I have a save about 5m from the docking port, and I have tried this probably about 10 times with no success.  I could see if I was coming in at a 30 degree or 45 degree angle, but my approach angle is not that severe, and a few times I've gotten it to almost no angle without success.

I've tried disabling SAS at the last minute, disabling SAS on the station......enabling SAS for one but not the other, enabling SAS for both.....nothing is working.  Anyone have this kind of problem with docking ports, and suggestions?

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If you aren't confused yet, here's my 2cents.

If you are already able to get within a couple hundred meters, you are more that halfway there.

If you arent purposely moving towards or away from the desired dock, the drift will become apparent.

1. Once you are close, like 500m or less, slow your approach

2. When you are within 100 - 200m slow more to under 5m/sec

3. Switch camera view to "locked" and make sure that the top of your ship is "up"

4. Select the port you want to dock with and 'eyeball' your alignment and drift correction

5. then either fly the Nav Ball into dock, or do it visually.

It one of the hardest things to do in KSP good luck.

Cheers!

Edit = I think that the docking port magnet repelling thing had something to do with a MOD, but I don't know for sure, it was discussed in the forum before this.

Edited by GrouchyDevotee

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3 hours ago, djr5899 said:

So, the good news is after docking my Habitation module to my Science module earlier tonight, I also managed to launch a Fuel module, and get it docked as well. Definitely learning a lot more about how to counter-act forces and speed. Looking forward to continue to build onto my Space Station, and have regular fuel supply and Kerbal rotation flights.

I am still seeing one issue though that I cannot figure out, and I mentioned it above.   Attached to my Science Module was my Escape Pod, big enough to carry all the crew on the station.  I wanted to move this to a different connector dock, to essentially form an X shaped station.  Fairly simple you would figure.  Just undock the Escape Pod, move it around to the docking port, and dock it.  No major rendezvous to deal with.

My Escape Pod has 2 sets of RCS thrusters, but they were balanced for docking the Science Module to the station.  There is a bit of drift from true input.  When attempting to dock to the new Space Station port, I am hitting it at a slight angle.....maybe 15 degrees from true perpendicular.  As soon as my Escape Pod touches the docking port on the station, the magnet acts like they are like magnets, and it flings my escape pod away from the station in a nasty spin.  I have a save about 5m from the docking port, and I have tried this probably about 10 times with no success.  I could see if I was coming in at a 30 degree or 45 degree angle, but my approach angle is not that severe, and a few times I've gotten it to almost no angle without success.

I've tried disabling SAS at the last minute, disabling SAS on the station......enabling SAS for one but not the other, enabling SAS for both.....nothing is working.  Anyone have this kind of problem with docking ports, and suggestions?

15 degrees is still quite a bit off, unless the ship being docked is very small (e.g. a Mk1 pod, FL-T200 and a terrier at the back). The trick of disabling SAS would probably work with that kind of angle and that kind of craft, but for something larger, then the angle will need to be more accurate.

The magnets are really just a fudge, to allow docking to be not too painful (i.e. requireing essentially perfect alignment to succeed) but they only provide a bit of assistence.

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5 hours ago, purpleivan said:

15 degrees is still quite a bit off, unless the ship being docked is very small (e.g. a Mk1 pod, FL-T200 and a terrier at the back). The trick of disabling SAS would probably work with that kind of angle and that kind of craft, but for something larger, then the angle will need to be more accurate.

I'm suspicious that the docking pod is actually *too* small, rather than not small enough, which is why it's getting thrown around by the magnets. 

Can you furnish us with a screenshot @djr5899? Also what's your final approach speed?

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My approach speed is 0.1 to 0.2 m/s.  Not home to get a screenshot, but my craft has roughly the following parts (from top to bottom as assembled):

Clamp-O-Tron Docking Port 
MK 1-3 Command Pod 
3 Mk2-R Radial Parachutes 
PPD-10 Hitchhiker Storage 
4 RV-105 RCS Thrusters
Heat Shield 2.5m 
TD-25 Decoupler 
FL-R1 RCS Fuel Tank 
Rockomax X200-32 Fuel Tank 
4 RV-105 RCS Thrusters 
Poodle Engine 

I can post a few screenshots when I get on later tonight.  Can you post videos here, like links to YouTube?  I can take a video capture as well.  I gave it a few more tries last night, and it is just odd.  I even backed the craft away, got it a bit straighter on, and you can see the magnets kick in, it looks like it is about to settle in and lock, and then bam, it's like it fired a gun and flings the craft away.  I'd just like to figure out if it my lack of docking experience, or something else going on.  Knowing that the RCS isn't properly balanced and the controls drift, because the pod was originally kind of dual purpose....tug to help get one module attached, and then meant to be Escape Pod afterwards.....I may just fly this back to Kerbin, and build a balanced RCS escape pod.  But curious if this is a common occurrence, or just bad piloting.  :D

 

 

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I know! Don’t put docking ports, put claws!

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On 5/20/2018 at 8:19 PM, djr5899 said:
  • Building vessels with RCS thrusters spaced properly to get proper movements without drifting.
  • Is there a way to make STS movement to defined markers (Target, prograde, retrograde, etc) move fast without turning on engines?   When you have a larger vessel to try and dock, it moves so slow or won't move at all without thrusters.  Would adding more reaction wheels help that?
  • Does Rockomax Hubmax multi point connect need docking ports placed on them to dock?  Or to have Docking Port mod identify them?
  • Tips on how to avoid getting in pattern of having orbiting object you are trying to dock continually get within 50m only to start drifting away from you?
  • Any tips on camera setting to use?  I constantly feel like I am adjusting the camera, or getting it stuck at the point where it won't spin one direction anymore.
  • Any mods that will dock for you once you get to a certain distance away?

Almost all of this, TBH,  is only solved with the use of mods. Vanilla is just too lacking on those matters. A few notes:

1. There is a mod called RCS build aid. With it you see in the VAB your empty and full CoM,  and it is much easier to position the RCS in a proper manner. It also projects torque and thrust vectors.

 

2. Some sort of docking cam is a must for orienting a docking procesure. I personally like  KURS.

 

Both are available in SPACEDOCK.

Edited by Daniel Prates

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I actually dislike the magnets being as powerful as they are. Typically, I'll use Tweakable Everything to tone down the force, as well as the kick it gives you when you disconnect the ports.

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7 hours ago, djr5899 said:

My approach speed is 0.1 to 0.2 m/s.  Not home to get a screenshot, but my craft has roughly the following parts (from top to bottom as assembled):

Clamp-O-Tron Docking Port 
MK 1-3 Command Pod 
3 Mk2-R Radial Parachutes 
PPD-10 Hitchhiker Storage 
4 RV-105 RCS Thrusters
Heat Shield 2.5m 
TD-25 Decoupler 
FL-R1 RCS Fuel Tank 
Rockomax X200-32 Fuel Tank 
4 RV-105 RCS Thrusters 
Poodle Engine 

I can post a few screenshots when I get on later tonight.  Can you post videos here, like links to YouTube?  I can take a video capture as well.  I gave it a few more tries last night, and it is just odd.  I even backed the craft away, got it a bit straighter on, and you can see the magnets kick in, it looks like it is about to settle in and lock, and then bam, it's like it fired a gun and flings the craft away.  I'd just like to figure out if it my lack of docking experience, or something else going on.  Knowing that the RCS isn't properly balanced and the controls drift, because the pod was originally kind of dual purpose....tug to help get one module attached, and then meant to be Escape Pod afterwards.....I may just fly this back to Kerbin, and build a balanced RCS escape pod.  But curious if this is a common occurrence, or just bad piloting.  :D

 

 

Have you tried turning off RCS just before the magnets kick in? The RCS might be fighting the pull. And be sure to hit CapsLock so the RCS doesn’t kick as hard; it also balances RCS if it’s not too unbalanced 

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