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International Space Station (ISS) => ISS Section => Topic started by: Suzy on 12/26/2006 08:19 pm

Title: Russian docking mechanisms difference?
Post by: Suzy 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?

Title: RE: Russian docking mechanisms difference?
Post by: lmike 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
Title: Re: Russian docking mechanisms difference?
Post by: nacnud 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.
Title: Re: Russian docking mechanisms difference?
Post by: lmike 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.
Title: Re: Russian docking mechanisms difference?
Post by: Suzy on 12/26/2006 11:20 pm
Thanks!
Title: Re: Russian docking mechanisms difference?
Post by: nacnud 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.
Title: Re: Russian docking mechanisms difference?
Post by: Jorge on 12/28/2006 01:39 am
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
Title: Re: Russian docking mechanisms difference?
Post by: nacnud on 12/28/2006 11:32 am
Interesting I had no idea, thanks.
Title: Re: Russian docking mechanisms difference?
Post by: Danderman on 12/28/2006 12:42 pm
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.

Title: Re: Russian docking mechanisms difference?
Post by: bobthemonkey 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.
Title: Re: Russian docking mechanisms difference?
Post by: lmike 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.
Title: Re: Russian docking mechanisms difference?
Post by: Danderman on 12/29/2006 04:11 pm
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.

Title: Re: Russian docking mechanisms difference?
Post by: Jorge on 12/30/2006 02:34 am
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
Title: Re: Russian docking mechanisms difference?
Post by: lmike 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)
Title: Re: Russian docking mechanisms difference?
Post by: Jorge 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.
--
JRF
Title: Re: Russian docking mechanisms difference?
Post by: lmike on 12/30/2006 06:51 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.
Title: Re: Russian docking mechanisms difference?
Post by: Jorge on 12/30/2006 08:44 pm
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
Title: Re: Russian docking mechanisms difference?
Post by: sbt on 12/30/2006 10:37 pm
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
Title: Re: Russian docking mechanisms difference?
Post by: Jim on 12/31/2006 02:41 pm
It is LIDS.  No other terms
Title: Re: Russian docking mechanisms difference?
Post by: Danderman on 12/31/2006 03:50 pm
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.
Title: Re: Russian docking mechanisms difference?
Post by: sbt on 12/31/2006 04:46 pm
Quote
Jim - 31/12/2006  3:24 PM
It is LIDS.  No other terms
Currently and/or in the past and/or outside NASA?

I have seen multiple names and 'LIDS (the US name for IDBS)' in an ESA
document.

Also there are these documents:

http://www.grc.nasa.gov/WWW/RT/2005/RX/RX20M-steinetz2.html
http://research.jsc.nasa.gov/PDF/Eng-3.pdf
http://users.wpi.edu/~aiaa/esas/ESAS.REPORT.05.PDF

The last refers to ADBS as the project developing LIDS and the JSC
flyer to ADBS 'leveraging' LIDS work for X-38

I only found the JSC flyer today (missed it yesterday). Interestingly
the JSC flyer refers to assessing if two or more different sizes are
required and it is possible to have some mountings where two different
size versions are mounted concentrically.

I take it that the rest of the post is largely correct?

Rick
Title: Re: Russian docking mechanisms difference?
Post by: Jim on 12/31/2006 04:50 pm
Constellation documentation specifies LIDS
Title: Re: Russian docking mechanisms difference?
Post by: sbt on 12/31/2006 06:54 pm
Quote
sbt - 31/12/2006  5:29 PM
.. and it is possible to have some mountings where two different
size versions are mounted concentrically.

Make that
... and IF it is possible ...

Rick
Title: Re: Russian docking mechanisms difference?
Post by: Suzy on 01/15/2007 06:55 am

I just found that my copy of the NASA International Space Station Familiarization PDF has brief descriptions of each docking system, so I will copy them here:

9.4.1 Common Berthing Mechanism/Manual Berthing Mechanism

The Common Berthing Mechanism (CBM) connects one pressurized module to another pressurized module on the U.S. segment. The CBM has an active and a passive half The active half contains a structural ring, capture latches, alignment guides, powered bolts, and controller panel assemblies. Only the active half of the CBM is connected to power and data. The passive half has a structural ring, capture latch fittings, alignment guides, and nuts. During the installation of a module that uses CBM, a robotic arm moves the module with the passive half into the capture envelope of the active half. Following this, the latching process begins. .Similar to the CBM active half is the Manual Berthing Mechanism (MBM). The MBM serves as a temporary attachment point and is located on the Z1 truss segment. The MBM is manually operated by an EVA crew person and can be mated with any passive CBM.

9.4.5 Androgynous Peripheral Attach System

The Androgynous Peripheral Attach System (APAS) serves two functions on Station. One is to dock the orbiter and the other is to connect the Functional Cargo Block (FGB) to Pressurized Mating Adapter 1 (PMA 1). An APAS is located on each of the three PMAs and on the FGB forward side. The components of the APAS (Figure 9-11) are a structural ring, a movable ring, alignment guides, latches, hooks, dampers, and fixers. The APAS is a Russian design and is designed to mate with an exact copy of itself (hence the name androgynous). Each APAS can act as the passive half or the active half. The APAS was also used on the Shuttle/Mir flights and was referred to as the Androgynous Peripheral Docking System.

9.4.6 Probe/Drogue Docking System/Hybrid Docking System

The Probe/Drogue or Hybrid docking systems are used to mate all Russian modules together including the Science Power Platform (SPP) segments (post 8A). This system has an active half and a passive half (Figure 9-12). The active half has a probe, a capture latch at the tip of the probe, alignment pins, hooks, and shock absorbers. The passive half has a drogue, a receiving cone, and a structural ring. The probe enters the receiving cone and the capture latch activates as the tip of the probe enters the drogue. The shock absorbers damp out the relative motion, then the probe retracts bringing the  two halves together. Next, the hooks mate the two halves and the capture latch is released so the crew can open the hatch.

The Hybrid Docking System has a larger diameter hatch, a larger structural ring, and more hooks than the regular probe/drogue. This type of design results in a more robust structure capable of handling loads larger than what Probe/Drogue was designed to handle. The Hybrid Docking System is used in areas where increased forces on the joints between docked objects, such as the SPP-to-Service Module connection, are expected. The larger hatch also permits larger cargo to pass through the hatch.

 
Title: Re: Russian docking mechanisms difference?
Post by: on 01/15/2007 03:39 pm
LIDS used to be called ADBS when it was developed for the X38.

Here's an article:
http://research.jsc.nasa.gov/PDF/Eng-3.pdf

And there is a small (and oddly, accurate) article at wiki:

http://en.wikipedia.org/wiki/Low_Impact_Docking_System


LIDS operates like this:

One side is active, one is passive.  Once the two spacecraft have been maneuvered into the capture window, the active side extends - using 6 linear actuators.  LIDS uses an active force feedback 6DOF system that allows the active side to align with the passive side, without slamming into it as APAS requires.  Once aligned, electromagnets are engaged.  The force feedback control system then dampens out any residual movement between the two spacecraft - think hydraulic shock absorbers, even though no springs or hydraulics are involved, that's what it looks like in operation.  The active side then retracts.  When fully retracted, a number of docking clamps are engaged and the two units are pulled hard together completing an air tight seal.

LIDS cannot dock with APAS.  There will (probably) be an APAS/LIDS adapter to go to the ISS on the first two CEV flights.  The ISS LIDS will be a passive system.  There is no plan to ever put APAS on any Constellation vehicle AFAIK.

LIDS is not a "follow on" to APAS, but rather a replacement for it.  APAS is designed and built by the Russians, LIDS is designed and built by NASA.  They are not related in any way except that they do similar functions.

As regards the article on silicone elastomers - that's a major design issue.  Since LIDS is androgynous and each is identical, each LIDS has to have this soft sealing gasket, so when you dock you're docking gasket to gasket, rather than gasket to metal, which would be preferable.  So, you need a material that is flexible, sealable, and can withstand the rigors of being exposed to space.  Which is one reason I'm glad I'm not a materials guy.
Title: Re: Russian docking mechanisms difference?
Post by: bmuniz on 01/23/2007 03:37 am
QUOTE]Jorge - 29/12/2006  9:34 PM
AFAIK, the only difference between 89 and 95 is on the "active" side,
[/QUOTE]

Jorge,

Some aditional info to clarify, based mainly on my vague recollection of my structural dynamics days at Rockwell in the early '90s.

On the APAS-89, which was used at Mir, either side can be "active," so it's truly an "androgynous" system.  Prior to docking, one side is kept latched down ("passive" side"), and the other side is extended to attenuate structural loads ("active" side), but EITHER side can be selected to be active prior to docking.  Therefore, any APAS-89 unit can dock to any other one.

But APAS-89 units were developed for Soyuz-class spacecraft (typically 6500 kg or so at docking).  For docking the Shuttle to ISS (~100,000 kg), the mechanism was modified (by RSC-E & Rockwell) to be "softer" to prevent structural loads exceedances on deployed ISS components like the PV Arrays.  Because of this, one side was permanently latched down (and the unnecessary control electronics removed, reducing mass).  This is the APAS-95 configuration: a "Passive" APAS-95 on ISS, and an Active APAS-95 on the matching Shuttle.  An Active APAS-95 can dock to Passive APAS-95 or Active APAS-95, but Passive APAS-95 (on ISS) can only dock with Active APAS-95 -- therefore, APAS-95 comes in "pairs", and APAS-89 doesn't.

IIRC, NASA/JSC Missions Operations Directorate (MOD) has stated that vehicles smaller than the Shuttle might be able to use the APAS-89 to dock to ISS, but it would take some structural loads analysis to confirm/approve (which is the case for any docking/berthing of a new vehicle to ISS anyway).

I remember seeing a briefing on LIDS (and the patent) that stated that APAS is not fully androgynous, which is a bit of misdirection since APAS is fully androgynous unless modified not to be.

Ben Muniz
Title: Re: Russian docking mechanisms difference?
Post by: Jorge on 01/23/2007 04:21 am
Quote
bmuniz - 22/1/2007  10:37 PM

Quote
Jorge - 29/12/2006  9:34 PM
AFAIK, the only difference between 89 and 95 is on the "active" side,

Jorge,

Some aditional info to clarify, based mainly on my vague recollection of my structural dynamics days at Rockwell in the early '90s.

On the APAS-89, which was used at Mir, either side can be "active," so it's truly an "androgynous" system.  Prior to docking, one side is kept latched down ("passive" side"), and the other side is extended to attenuate structural loads ("active" side), but EITHER side can be selected to be active prior to docking.  Therefore, any APAS-89 unit can dock to any other one.

But APAS-89 units were developed for Soyuz-class spacecraft (typically 6500 kg or so at docking).  For docking the Shuttle to ISS (~100,000 kg), the mechanism was modified (by RSC-E & Rockwell) to be "softer" to prevent structural loads exceedances on deployed ISS components like the PV Arrays.  Because of this, one side was permanently latched down (and the unnecessary control electronics removed, reducing mass).  This is the APAS-95 configuration: a "Passive" APAS-95 on ISS, and an Active APAS-95 on the matching Shuttle.  An Active APAS-95 can dock to Passive APAS-95 or Active APAS-95, but Passive APAS-95 (on ISS) can only dock with Active APAS-95 -- therefore, APAS-95 comes in "pairs", and APAS-89 doesn't.

IIRC, NASA/JSC Missions Operations Directorate (MOD) has stated that vehicles smaller than the Shuttle might be able to use the APAS-89 to dock to ISS, but it would take some structural loads analysis to confirm/approve (which is the case for any docking/berthing of a new vehicle to ISS anyway).

I remember seeing a briefing on LIDS (and the patent) that stated that APAS is not fully androgynous, which is a bit of misdirection since APAS is fully androgynous unless modified not to be.

Ben Muniz

Thank you Ben, that fills in a lot of pieces for me. I remembered that APAS-95 was needed to reduce ISS loads, and I recalled never seeing a "passive" APAS-89 (at least passive in the sense that the PMAs are on ISS) but I never put those two facts together before. Well, actually there was one APAS-89 that I always had a question about - the never-used "side" APAS on the Kristall module on Mir. That one never looked fully functional to me, but maybe I've just never seen a good enough photo of it to see the ballscrews. I understand that it was originally intended to berth logistics modules carried up by Buran. Have you heard anything about it?
--
JRF
Title: Re: Russian docking mechanisms difference?
Post by: bmuniz on 01/23/2007 12:56 pm
Quote
Jorge - 22/1/2007  11:21 PM
Well, actually there was one APAS-89 that I always had a question about - the never-used "side" APAS on the Kristall module on Mir. That one never looked fully functional to me, but maybe I've just never seen a good enough photo of it to see the ballscrews. I understand that it was originally intended to berth logistics modules carried up by Buran. Have you heard anything about it?
--
JRF

Jorge,

I never really dug into the tech details of that one.  David Anderman may have more info on its intended use, or we can ask our Moscow rep if you really need the info.  Just let me know.

Ben

Title: Re: Russian docking mechanisms difference?
Post by: on 01/23/2007 03:07 pm
Jorge, there are some older docking modules over here in B13 if you'd like to take a look at them.  A pair of ASTP (Apollo/Soyuz) mechanisms and an APAS, I think from 1995.  I've been told that taking pictures would not be an issue, so I'll try to get some over the next few days.  There are also a few smaller LIDS prototype pieces lying around.
Title: Re: Russian docking mechanisms difference?
Post by: Jorge on 01/24/2007 11:27 pm
Quote
bmuniz - 23/1/2007  7:56 AM

Quote
Jorge - 22/1/2007  11:21 PM
Well, actually there was one APAS-89 that I always had a question about - the never-used "side" APAS on the Kristall module on Mir. That one never looked fully functional to me, but maybe I've just never seen a good enough photo of it to see the ballscrews. I understand that it was originally intended to berth logistics modules carried up by Buran. Have you heard anything about it?
--
JRF

Jorge,

I never really dug into the tech details of that one.  David Anderman may have more info on its intended use, or we can ask our Moscow rep if you really need the info.  Just let me know.

Ben


Don't really need it, just idle curiosity. No need to spin up folks in Moscow. Thanks for the offer, though.
--
JRF
Title: Re: Russian docking mechanisms difference?
Post by: Jorge on 01/24/2007 11:29 pm
Quote
bhankiii - 23/1/2007  10:07 AM

Jorge, there are some older docking modules over here in B13 if you'd like to take a look at them.  A pair of ASTP (Apollo/Soyuz) mechanisms and an APAS, I think from 1995.  I've been told that taking pictures would not be an issue, so I'll try to get some over the next few days.  There are also a few smaller LIDS prototype pieces lying around.

Thanks, may take you up on that. The ASTP (APAS-75) mechanisms sound cool - for APAS, we've got a full-size trainer in B9 now.
--
JRF
Title: Re: Russian docking mechanisms difference?
Post by: on 01/25/2007 12:07 am
I posted some photos over in the Historical section.
Title: Re: Russian docking mechanisms difference?
Post by: TR1 on 06/20/2007 07:20 pm

"... the unnecessary control electronics removed, reducing mass ..."


For an APAS-89 are there contingency undock pyrobolts on both halves of the system?  

Were the pyrobolts removed from the passive side for APAS-95?    

-Tim
Title: Re: Russian docking mechanisms difference?
Post by: duane on 01/22/2009 04:43 am
How did the ISS end up using a Russian designed docking system ?

And, why is Orion/Altair going to use the LIDS docking system instead of the APAS system ? LIDS will require ANOTHER adaptor for Orion to dock with the ISS

Thanks
DUane
Title: Re: Russian docking mechanisms difference?
Post by: The-Hammer on 01/22/2009 05:29 am
IANAE

APAS was already in use on MIR. When Shuttle-MIR was started up the orbiters needed a way to dock and the APAS met that need. Having already designed and built the ODS for the Shuttle-MIR program, there was no sense designing and building a new system for ISS. 

Orion/Altair is using LIDS because it is US-built. Buying 8 APASs* (plus some spares I imagine) from Russia for Shuttle-MIR and ISS was reasonable, but having to buy a new APAS for every Orion and Altair constructed is not.

The two APAS/LIDS adapters can probably scrounge APASs from the ODSs when Shuttle stands down.

* 3 ODSs, 3 PMAs, plus 2 on the MIR Docking Module.
Title: Re: Russian docking mechanisms difference?
Post by: litton4 on 01/22/2009 06:55 am
* 3 ODSs, 3 PMAs, plus 2 on the MIR Docking Module.

Wouldn't there have been 4 ODSs built - one for each shuttle?
Title: Re: Russian docking mechanisms difference?
Post by: The-Hammer on 01/22/2009 07:22 am
Columbia never received an ODS. She was too heavy for the high-inclination space station missions.

According to a pre-107 FAWG posted on L2, she was scheduled to make one visit only to ISS for the STS-118 mission. She would have needed an ODS for that, but her only two missions after 118 were to the Hubble. Discovery was undergoing an OMMDP at the time of 107 which would have extended until shortly after the scheduled launch of 118. Just speculation but, it's possible they were planning to use Discovery's ODS in Columbia for the 118 mission before returning it to Discovery.

EDIT: To clarify: Columbia could only fly the 118 mission because it was very light for an ISS mission. Just the S5 truss segment, SpaceHab Logistics Single Module, and an ICC on which the EAS would have been downmassed.
Title: Re: Russian docking mechanisms difference?
Post by: litton4 on 01/22/2009 01:32 pm
Columbia never received an ODS. She was too heavy for the high-inclination space station missions.

Ok, thanks for the clarification - I didn't realise that Columbia was *that* much heavier than the other orbiters.
Title: Re: Russian docking mechanisms difference?
Post by: Jim on 01/22/2009 02:54 pm
Columbia never received an ODS. She was too heavy for the high-inclination space station missions.

Ok, thanks for the clarification - I didn't realise that Columbia was *that* much heavier than the other orbiters.

5-6000 lbs
Title: Re: Russian docking mechanisms difference?
Post by: TR1 on 01/26/2009 03:31 pm

* 3 ODSs, 3 PMAs, plus 2 on the MIR Docking Module.

3 - ODSs
1 - ODS spare
1 - ICM
3 - PMAs

I'm not sure about the MIR versions.  Maybe someone else can fill that in.

Title: Re: Russian docking mechanisms difference?
Post by: JayP on 01/26/2009 04:01 pm
Because of this, one side was permanently latched down (and the unnecessary control electronics removed, reducing mass).  This is the APAS-95 configuration: a "Passive" APAS-95 on ISS, and an Active APAS-95 on the matching Shuttle. 

More than just the electronics were removed. If you look at pictures of PMA 2 durring shuttle docking, you can see that the capture latches in the middle of the guide pedals are absent. The actuators for extending the ring appear to be not their either, but I can't really tell.