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?
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.
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.
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.
Danderman - 29/12/2006 10:54 AMQuotebobthemonkey - 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.
Jorge - 29/12/2006 7:17 PMQuoteDanderman - 29/12/2006 10:54 AMQuotebobthemonkey - 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.
lmike - 30/12/2006 2:13 AMQuoteJorge - 29/12/2006 7:17 PMQuoteDanderman - 29/12/2006 10:54 AMQuotebobthemonkey - 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)
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.
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
Jim - 31/12/2006 3:24 PMCurrently and/or in the past and/or outside NASA?
It is LIDS. No other terms
sbt - 31/12/2006 5:29 PM
.. and it is possible to have some mountings where two different
size versions are mounted concentrically.
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.
bmuniz - 22/1/2007 10:37 PMQuoteJorge - 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
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
bmuniz - 23/1/2007 7:56 AMQuoteJorge - 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
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.
* 3 ODSs, 3 PMAs, plus 2 on the MIR Docking Module.
Columbia never received an ODS. She was too heavy for the high-inclination space station missions.
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.
* 3 ODSs, 3 PMAs, plus 2 on the MIR Docking Module.
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.