What's required for orbital docking?

[guitarxe]

I haven't played career much, mostly always only sandbox or the old Science mode, but now with Career there is the building upgrades thing, which affects gameplay elements like maneuver nodes. So I know already that I don't have maneuver nodes until I upgrade the tracking station, which is ok for now, but I want to dock two vessels in space and for that I need to at least see their separation thingy on the orbital lines. Is there something I need to unlock to see that, or I should be good to go from the get-go?

[Snark]

You'll need two things:

• Patched conics (upgrade the Tracking Station)
• Flight planning (upgrade Mission Control)

Flight planning not only provides maneuver nodes, but IIRC, also lets you set a target vessel, which is the thing you want for setting up a rendezvous.

It's not impossible to do without, but it's a whole lot easier with... and the first upgrade to Mission Control is pretty cheap (I think it's a bit over 100K funds), which is not too hard in early career.

[Kerbart]

17 minutes ago, Snark said:

You'll need two things:

• Patched conics (upgrade the Tracking Station)
• Flight planning (upgrade Mission Control)

In addition to that, having docking ports, even if they're just the juniors, really, really helps.

[Snark]

2 minutes ago, Kerbart said:

In addition to that, having docking ports, even if they're just the juniors, really, really helps.

lol... well, yeah, good point.     And RCS thrusters too, while we're at it.

However, my impression was that primarily what the OP's interested in was the upgrades needed to get a rendezvous.

[guitarxe]

Yeah, that's what I wanted to find out, thanks

[Geschosskopf]

38 minutes ago, Snark said:

lol... well, yeah, good point.     And RCS thrusters too, while we're at it.

However, my impression was that primarily what the OP's interested in was the upgrades needed to get a rendezvous.

And the RCS thrusters must be balanced, which means you should probably use the RCS Build Aid mod to get them in the right places.

[Snark]

3 minutes ago, Geschosskopf said:

And the RCS thrusters must be balanced, which means you should probably use the RCS Build Aid mod to get them in the right places.

Or just hit caps lock to have them auto-balance themselves.

[Geschosskopf]

9 minutes ago, Snark said:

Or just hit caps lock to have them auto-balance themselves.

I must not be tardy in my resposne here, Sir Tardigrade.  The fine control mode only works for ships of insignificant mass, and then only when their negligible mass is concentrated near their centers.  In all other cases, and especially when docking things weighing a few hundred tons each, the fine control mode is worse than useless and you'll rue the day you didn't use RCS Build Aid

 

Edited April 4, 2016 by Geschosskopf

[Snark]

41 minutes ago, Geschosskopf said:

I must not be tardy in my resposne here, Sir Tardigrade.  The fine control mode only works for ships of insignificant mass, and then only when their negligible mass is concentrated near their centers.  In all other cases, and especially when docking things weighing a few hundred tons each, the fine control mode is worse than useless and you'll rue the day you didn't use RCS Build Aid

Fair 'nuff, though I've used it when docking a 100+ ton tanker to a 100+ ton interplanetary mothership with no problems.  (Maybe it's just that I'm unusually patient.)

Bigger ships just means bigger RCS thrust is required.

Admittedly, multi-hundred-ton things are not usually what I'm in the habit of docking, so you may have a point there.  However, since this isn't primarily a thread about "how to dock juggernauts", I think fine control is a relevant bit of advice. 

[Geschosskopf]

9 minutes ago, Snark said:

However, since this isn't primarily a thread about "how to dock juggernauts", I think fine control is a relevant bit of advice. 

Agreed, but one thing leads to another, you know.

The fine control thing, however, does have limits even at the small end of the mass spectrum.  It really isn't much help for even a tiddler of a ship if the thrusters are way out of balance.

 

[Wemb]

13 hours ago, Snark said:

Or just hit caps lock to have them auto-balance themselves.

.. And put them in sensible places round your end-stage's CoM.  I've never used RCS balancer, and it's certainly not needed for small lightweight craft that can use reaction wheels to turn.  Snark's advice on using Caps-lock is much more useful till you're trying to dock fuel tankers.

Wemb

[Snark]

12 hours ago, Geschosskopf said:

The fine control thing, however, does have limits even at the small end of the mass spectrum.  It really isn't much help for even a tiddler of a ship if the thrusters are way out of balance.

Well, yes.  For example, if you have a long skinny ship and put a single ring of RCS thrusters way out at one end of the ship, there's basically nothing that can help you.

However, there's a pretty big gap between "I can make a ship that's not egregiously wrong" and "I can make a ship that gets the RCS thrusters placed perfectly." 

The simply-hit-caps-lock thing works for people who fall into that gap, which is a pretty big segment of the KSP population, I suspect.  For folks who simply have no idea whatsoever about how to place RCS, then yes, I could see how RCS Build Aid may be helpful.

28 minutes ago, Wemb said:

And put them in sensible places round your end-stage's CoM.  I've never used RCS balancer, and it's certainly not needed for small lightweight craft that can use reaction wheels to turn.  Snark's advice on using Caps-lock is much more useful till you're trying to dock fuel tankers.

It's not just about reaction wheels and turning.  It's about translation.

For example, I've never used RCS for turning, ever.  I do all my turning using reaction wheels alone.  I use RCS solely for doing translation during docking.  (Yes, that means a lot of tedious turning RCS on and off as I'm fine-tuning my position and orientation, which is a hassle.  Fortunately that's getting fixed in 1.1, because there's a new feature that lets you toggle individual axis capabilities of RCS thrusters the same way you can do it for aero control surfaces in 1.0.5.  So for example, in the VAB you can set up your RCS thrusters to "never contribute to rotation, ever," if so desired, which is perfect for the way I use them.  I'm turning handsprings over this feature.  But that's a 1.1 thing, and I don't want to derail this thread, so I'll shut up about it now.)

Even if you're doing all your rotation with reaction wheels, the RCS placement still affects you for translation.

[Geschosskopf]

6 minutes ago, Snark said:

For example, I've never used RCS for turning, ever.  I do all my turning using reaction wheels alone.

I usually do this, too, to save RCS fuel.  But some ships are so big they also need RCS for rotation

 

[Kerbart]

2 minutes ago, Snark said:

It's not just about reaction wheels and turning.  It's about translation.

For example, I've never used RCS for turning, ever.  I do all my turning using reaction wheels alone.  I use RCS solely for doing translation during docking.  (...)

Even if you're doing all your rotation with reaction wheels, the RCS placement still affects you for translation.

Of course it does but as long as you place them symmetrically around the COM things should be just fine. I've never used RCS balancer, I just eye-ball it and that approach works fine for me. I don't like complex ships; that probably makes a difference. One set of RCS thrusters: close to the COM. Two sets: away from RCS, both at the same distance of the COM. Three sets: One & Two combined. Four sets: never went there.

[radonek]

Fun fact: You can perform orbital rendezvous without any upgrades whatsoever, there is nothing to prevent two ships occur at same place at same time. Except its exceptionaly hard. If you have some idea about target orbital parameters (hint: early rescue contracts have zero inclination and close to circular) and get on (hopefully) similar orbit, you can get very rough idea of relative speed from relative distance indicator in camera view (which comes from some onboard radar, right?). With some luck (and some quickloading) its possible to get close enough and (with a lot more quickloading) slow enough to match orbits by eye.

That's the theory anyway. In practice, I managed to pull that off once and hope to never, ever do it again.

[Wemb]

On 04/04/2016 at 6:07 PM, radonek said:

Fun fact: You can perform orbital rendezvous without any upgrades whatsoever

Yeah, that sounds like excessive amounts of 'fun' to me :-)   I'm still planning on doing a kOS powered launch and then an entirely IVA and non-GUI rendezvous and docking at some point when I've found a readable manual for kOS (and, I hope, a RasterPropMonitor interface to it. That'll be fun enough for me. 

Wemb