Russian docking mechanisms difference?

• Russian docking mechanisms difference? by Suzy on 26 Dec, 2006 20:19

• Not sure if I should post this in the ISS Q&A thread, but I have been asked about "the difference between the 'hybrid' and 'classic' probe-and-cone docking mechanisms" and realized I don't have a clue! The only reference I could find by Googling is a reference to Zvezda, the Service Module:

  The aft docking port has a probe and cone docking mechanism to allow dockings by Progress resupply spacecraft and Soyuz piloted spacecraft. It also will be outfitted with an automated rendezvous and docking system. The forward docking ports all will have hybrid docking mechanisms to allow docking with the Zarya using the forward-facing port...

  Is there an explanation or diagrams available of what these actually are?

• #1 by lmike on 26 Dec, 2006 20:46
• http://www.hq.nasa.gov/office/pao/History/SP-4209/p172.htm etc... perhaps.  That's the 'classic', AFAIK.  I may be wrong with this exact picture, but the point is that the 'passive'/'active' mechanisms roles are fixed (target/docking spacecraft).  An "androgynous" on the other hand (the 'hybrid' in this nomenclature) docking adapter system (the APAS for example) can have both sides act as 'active'/'passive' and interchanged as needed (there are quite a few links on that system)
  
  [edit] here's a NASA link on the APAS: http://spaceflight.nasa.gov/dayfacts/2000/0118.html
• #2 by nacnud on 26 Dec, 2006 21:45
• The hybrid and classic docking systems are both probe and cone docking systems, the APAS-89 is an androgynous system. The differnce btween the classic and hybrid is size, hybrid is larger and is used to join modules together, all the front ports of Zvezda are hybrid ports. The smaller classic docking system is used to dock Soyuz and Progress vehicles. The rear ports of Zvezda and the nadir ports of Zarya and Pirs are this type. The front port of Zarya is an APAS.
• #3 by lmike on 26 Dec, 2006 23:10
• You are completely right, I missed the probe mechanism reference, didn't realize the 'hybrid' is a specific term for the specific hardware, to me it just seemed to refer to the APAS as a description of the operation mode, sorry for the confusion.
• #4 by Suzy on 26 Dec, 2006 23:20
• Thanks!
• #5 by nacnud on 26 Dec, 2006 23:48
• No probs, it's taken me ages just to find out that much, IIRC the two cone and probe systems are very simmilar execpt for the diameter of the opening.
• #6 by Jorge on 28 Dec, 2006 01:39
• Quote

  lmike - 26/12/2006  5:53 PM
  
  You are completely right, I missed the probe mechanism reference, didn't realize the 'hybrid' is a specific term for the specific hardware, to me it just seemed to refer to the APAS as a description of the operation mode, sorry for the confusion.

  
  "Hybrid" gets its name due to having the structural ring from the APAS and the probe-and-drogue mechanism from the "classic". As a result, APAS and Hybrid are hot-swappable provided the interface is pressurized. NASA had plans in 1997-2000 to convert the Zarya aft mechanism from Hybrid to APAS using an "FGB Pressure Dome" if required to dock the Interim Control Module. Fortunately Zvezda eventually launched and ICM was not required.
  --
  JRF
• #7 by nacnud on 28 Dec, 2006 11:32
• Interesting I had no idea, thanks.
• #8 by Danderman on 28 Dec, 2006 12:42
• Quote

  nacnud - 26/12/2006  2:28 PM
  
  The hybrid and classic docking systems are both probe and cone docking systems, the APAS-89 is an androgynous system. The differnce btween the classic and hybrid is size, hybrid is larger and is used to join modules together, all the front ports of Zvezda are hybrid ports. The smaller classic docking system is used to dock Soyuz and Progress vehicles. The rear ports of Zvezda and the nadir ports of Zarya and Pirs are this type. The front port of Zarya is an APAS.

  
  I do not believe that APAS-89 is used at ISS.
  
  
• #9 by bobthemonkey on 28 Dec, 2006 17:28
• APAS 89 is used in the PMA's to dock to the shuttle and the Zarya/PMA1 interface.
• #10 by lmike on 29 Dec, 2006 02:46
• Thank you.  That's why I love this board, just this thread educated me on several points I wasn't even aware of before.
• #11 by Danderman on 29 Dec, 2006 16:11
• Quote

  bobthemonkey - 28/12/2006  10:11 AM
  
  APAS 89 is used in the PMA's to dock to the shuttle and the Zarya/PMA1 interface.

  
  AFAIK, these are APAS-95 units.  If there is a source that definitely states that these are APAS-89, I would be surprised.
  
  
• #12 by Jorge on 30 Dec, 2006 02:34
• Quote

  Danderman - 29/12/2006  10:54 AM
  
  

  Quote

  bobthemonkey - 28/12/2006  10:11 AM
  
  APAS 89 is used in the PMA's to dock to the shuttle and the Zarya/PMA1 interface.

  
  AFAIK, these are APAS-95 units.  If there is a source that definitely states that these are APAS-89, I would be surprised.
  
  

  
  AFAIK, the only difference between 89 and 95 is on the "active" side, so the difference should only affect the PMA-1 APAS, which (again, AFAIK) is the only active APAS on ISS (it was used exactly once, for the berthing of the FGB on STS-88). FGB and PMA-2/3 are passive APAS.
  --
  JRF
• #13 by lmike on 30 Dec, 2006 07:30
• Quote

  Jorge - 29/12/2006  7:17 PM
  
  

  Quote

  Danderman - 29/12/2006  10:54 AM
  
  

  Quote

  bobthemonkey - 28/12/2006  10:11 AM
  
  APAS 89 is used in the PMA's to dock to the shuttle and the Zarya/PMA1 interface.

  
  AFAIK, these are APAS-95 units.  If there is a source that definitely states that these are APAS-89, I would be surprised.
  
  

  
  AFAIK, the only difference between 89 and 95 is on the "active" side, so the difference should only affect the PMA-1 APAS, which (again, AFAIK) is the only active APAS on ISS (it was used exactly once, for the berthing of the FGB on STS-88). FGB and PMA-2/3 are passive APAS.
  

  
  Please forgive my ignorance, but doesn't the 'androgynous' in the APAS refer to the interchangeability of the docking collars/mechanisms?  As such, would the 'active'/'passive' distinction re: the APAS be a misnomer?  Or is it that one can be re-configured into passive/active on demand? (still a bit confused about this one)
• #14 by Jorge on 30 Dec, 2006 18:15
• Quote

  lmike - 30/12/2006  2:13 AM
  
  

  Quote

  Jorge - 29/12/2006  7:17 PM
  
  

  Quote

  Danderman - 29/12/2006  10:54 AM
  
  

  Quote

  bobthemonkey - 28/12/2006  10:11 AM
  
  APAS 89 is used in the PMA's to dock to the shuttle and the Zarya/PMA1 interface.

  
  AFAIK, these are APAS-95 units.  If there is a source that definitely states that these are APAS-89, I would be surprised.
  
  

  
  AFAIK, the only difference between 89 and 95 is on the "active" side, so the difference should only affect the PMA-1 APAS, which (again, AFAIK) is the only active APAS on ISS (it was used exactly once, for the berthing of the FGB on STS-88). FGB and PMA-2/3 are passive APAS.
  

  
  Please forgive my ignorance, but doesn't the 'androgynous' in the APAS refer to the interchangeability of the docking collars/mechanisms?  As such, would the 'active'/'passive' distinction re: the APAS be a misnomer?  Or is it that one can be re-configured into passive/active on demand? (still a bit confused about this one)

  
  It's not a misnomer. The term "Androgynous" only applies to the mechanical interface; in theory any APAS can be mounted to any other APAS. But one interface *must* be "active", with an extensible capture ring with capture latches. The passive side has neither an extensible ring nor capture latches, but it does have two gangs of active hooks, like the active side.
  
  With non-androgynous systems like probe-and-drogue, you can only dock A->P, not A->A or P->P. With androgynous you can mount A->P or A->A, but you still can't do P->P.
  --
  JRF
• #15 by lmike on 30 Dec, 2006 18:51
• Ah, that's clear enough.  Thanks much.  This matter of precise terminology with regards to the APAS operation often comes up wrt dockings in other discussions, this has clarified it for me.  Sorry for sidetracking the thread a bit.
• #16 by Jorge on 30 Dec, 2006 20:44
• Quote

  lmike - 30/12/2006  1:34 PM
  
  Ah, that's clear enough.  Thanks much.  This matter of precise terminology with regards to the APAS operation often comes up wrt dockings in other discussions, this has clarified it for me.  Sorry for sidetracking the thread a bit.

  
  It was a good on-topic question, not a sidetrack at all. No apologies required.
  --
  JRF
• #17 by sbt on 30 Dec, 2006 22:37
• As a follow up, I get the impression from my reading that the follow on
  to APAS, various termed LIDS/ADBS/IDBS is basically an lightened APAS
  with a computer controlled electromagnetic latching system rather than
  the mechanical system APAS uses.
  
  My understanding is that the electromagnetic latching system requires
  less contact force to initiate capture than APAS, which uses (sprung?)
  mechanical latches. This in turn allows the whole structure to be
  lighter, negating the need for lightweight 'Passive' versions without
  the ring-extension mechanism. In effect all ADBS units are lightweight
  'Active' APAS units with magnetic latches (note that the two systems
  are NOT compatible)
  
  Thus all ADBS dockings are A->A (with only one unit used in the
  'Active' role?)
  
  Also the two systems (APAS and ADBS) share aperture sizes etc. so a
  module or spacecraft designed to mount one is relatively easy to modify
  to mount the other (I presume the major issue is power and control for
  the latches and extension system if ADBS is replacing an
  APAS(Passive)). Hence there is no major design issue regarding early
  Orion capsules using an APAS, other than ADBS probably being lighter.
  
  Rick
• #18 by Jim on 31 Dec, 2006 14:41
• It is LIDS.  No other terms
• #19 by Danderman on 31 Dec, 2006 15:50
• Quote

  
  Also the two systems (APAS and ADBS) share aperture sizes etc. so a
  module or spacecraft designed to mount one is relatively easy to modify
  to mount the other

  
  I believe that APAS and probe/cone (as well as hybrid) have similar mounting requirements (ie aperture sizes and bolt patterns), although I have not seen this documented anywhere. Of course, Soyuz TM-16 flew with APAS-89, so its clear that its possible to substitute APAS for probe and cone, but I believe that swap-out of Russian docking systems is fairly easy - I would not be surprised if the bolt pattern for probe and cone were identical to APAS.