Author Topic: Russian docking mechanisms difference?  (Read 23655 times)

Offline Suzy

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Russian docking mechanisms difference?
« on: 12/26/2006 08:19 PM »

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?


Offline lmike

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RE: Russian docking mechanisms difference?
« Reply #1 on: 12/26/2006 08:46 PM »
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

Offline nacnud

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Re: Russian docking mechanisms difference?
« Reply #2 on: 12/26/2006 09:45 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.

Offline lmike

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Re: Russian docking mechanisms difference?
« Reply #3 on: 12/26/2006 11:10 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.

Offline Suzy

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Re: Russian docking mechanisms difference?
« Reply #4 on: 12/26/2006 11:20 PM »
Thanks!

Offline nacnud

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Re: Russian docking mechanisms difference?
« Reply #5 on: 12/26/2006 11:48 PM »
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.

Offline Jorge

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Re: Russian docking mechanisms difference?
« Reply #6 on: 12/28/2006 01:39 AM »
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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.
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Offline nacnud

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Re: Russian docking mechanisms difference?
« Reply #7 on: 12/28/2006 11:32 AM »
Interesting I had no idea, thanks.

Offline Danderman

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Re: Russian docking mechanisms difference?
« Reply #8 on: 12/28/2006 12:42 PM »
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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.


Offline bobthemonkey

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Re: Russian docking mechanisms difference?
« Reply #9 on: 12/28/2006 05:28 PM »
APAS 89 is used in the PMA's to dock to the shuttle and the Zarya/PMA1 interface.

Offline lmike

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Re: Russian docking mechanisms difference?
« Reply #10 on: 12/29/2006 02:46 AM »
Thank you.  That's why I love this board, just this thread educated me on several points I wasn't even aware of before.

Offline Danderman

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Re: Russian docking mechanisms difference?
« Reply #11 on: 12/29/2006 04:11 PM »
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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.


Offline Jorge

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Re: Russian docking mechanisms difference?
« Reply #12 on: 12/30/2006 02:34 AM »
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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.
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Offline lmike

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Re: Russian docking mechanisms difference?
« Reply #13 on: 12/30/2006 07:30 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)

Offline Jorge

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Re: Russian docking mechanisms difference?
« Reply #14 on: 12/30/2006 06:15 PM »
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.
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