New more realistic handling of docking events

DaveS

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From an user/add-on dev perspective what I would like to see above all is for the current handling of docking events to be changed to a more realistic one that incorporates the two stages of a docking sequence which are the initial soft capture (AKA "soft-dock") and the later hard capture ("hard-dock"). Currently only the second stage is simulated, somewhat. The first stage is critical as it serves actually capture the opposing docking mechanism and allow the relative velocities to dampen out as you have one vehicle more or less slamming into another and if things aren't entirely right, can lead to either a bounce off (best case scenario) or damage to either mechanism (worst case scenario) which would prohibit any future attempts at docking.

And the worst case scenario has indeed happened in real life when Soyuz-10 tried to dock to Salyut-1 and they forgot to deactivate the flight control system which caused physical damage to the docking mechanism of Soyuz-10: http://www.russianspaceweb.com/soyuz10.html
 

Urwumpe

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I second this, this would be a pretty useful extension of Orbiter. I have no idea yet how to implement this with enough backwards-compatibility.

Maybe we need a new "Docking API 2.0" for this, so the old legacy docking API can be mapped onto a new docking physics model in the backend.
 

DaveS

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Maybe we need a new "Docking API 2.0" for this, so the old legacy docking API can be mapped onto a new docking physics model in the backend.
I like this way. A new API would bypass the legacy stuff and allow for a proper implementation that wouldn't have anything to do with the old system. That way things would not break and still allow a path forward.
 

Urwumpe

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Yes, but right now, there are two planning tasks to be done:

  1. Where is the docking code now? Which parts of the simulation and UI are affected?
  2. How should a new model be defined?
    1. What is the scope of the new model?
    2. Which parameters should it support out of the box?
    3. How to integrate callbacks into the process?
    4. Which UI behaviour should be default?
 

jedidia

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Does it even make sense to simulate soft docking without proper collision handling? As I understand it, it kind of relies on "kinetic guidance", so to speak, in the last seconds of approach...
 

Urwumpe

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Does it even make sense to simulate soft docking without proper collision handling? As I understand it, it kind of relies on "kinetic guidance", so to speak, in the last seconds of approach...

Well, it could still work fine with out full collision handling, but a vessel-vessel collision handling could have side-effects with docking.
 

Zatnikitelman

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Wouldn't this be more on the vessels themselves though? What if there's a docking system that incorporates three stages of docking? A very soft capture, soft capture, then hard dock? Or what if we're doing more of a science fiction ship and the handwaved explanation is the soft and hard dock are handled so fast that there's no discernible difference? I could see expanding a docking API to give options, but the current conversation in this thread almost seems to assume a two-step docking each time.
 

Pioneer

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Wouldn't this be more on the vessels themselves though? What if there's a docking system that incorporates three stages of docking? A very soft capture, soft capture, then hard dock? Or what if we're doing more of a science fiction ship and the handwaved explanation is the soft and hard dock are handled so fast that there's no discernible difference? I could see expanding a docking API to give options, but the current conversation in this thread almost seems to assume a two-step docking each time.
The crew Dragon addon simulates that. It has the docking extension for the soft dock, which then pulls the spacecraft in for the hard dock.
 

Xyon

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Wouldn't this be more on the vessels themselves though? What if there's a docking system that incorporates three stages of docking? A very soft capture, soft capture, then hard dock? Or what if we're doing more of a science fiction ship and the handwaved explanation is the soft and hard dock are handled so fast that there's no discernible difference? I could see expanding a docking API to give options, but the current conversation in this thread almost seems to assume a two-step docking each time.
If the mechanisms for docking are just API references in the core, though, then it's up to vessel implementation about how and when they're called, still.
 

gattispilot

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I am not expert what it a moveable dock could be made. So the carft soft docks. and the then the dock moves as the vessel is drawn closer to the other vessel?
 

jedidia

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and the then the dock moves as the vessel is drawn closer to the other vessel?
In my experience, moving dockports is a bit problematic because the position of the docked vessel doesn't update along with it without some hacks. That's something that could potentially be fixed, though.
 

BrianJ

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The crew Dragon addon simulates that. It has the docking extension for the soft dock, which then pulls the spacecraft in for the hard dock.
Yes, Crew Dragon DM2 does have a moving dock - but I had to introduce some clunky hacks to make it work without bad side effects.

My method was to un-dock the vessels - move the docking port - re-dock vessels (at every frame!).
Not only that but since (as far as I can tell) the Orbiter core performs a linear+angular momentum calculation for the combined docked vessels upon each docking event, the linear+angular velocities had to be checked at the beginning of each frame and reset at the end. ugh!

I had a different method for the HST SAL add-on, which also has a movable docking port - once docked, an attachment point was created on the target vessel at the docking port point, and then attached to SAL, and vessels then undocked, SAL docking port deleted.The attachment point could then be moved (together with target vessel), the SAL docking port also created at the new position, and then vessels redocked. Or something like that, anyway. agh!

Maybe an easier way to do this would be if docking ports could also be treated as attachment points?
I dunno, maybe the programming wizards here can think of a way to do it.
Good luck!

BrianJ
 

Donamy

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Maybe the rotation bug with the RMS could be fixed also. :rolleyes:
 

DaveS

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Maybe the rotation bug with the RMS could be fixed also. :rolleyes:
It is fixed, at least if you use D3D9Client and have activated Absolute animstion handling. It has nothing to do with Orbiter's current limitations when it comes to docking event handling.
 
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