Talk:Common Berthing Mechanism/Archive 1

CBM as a docking port

Added info on the use of CBM as as means of HTV and Dragon docking in the future.Subzero788 | talk 03:44, 14 November 2006 (UTC)

No CBM ever acts as a docking port, per se, since (by definition) a Berthing Mechanism cannot be kinetically actuated (whereas a true Docking mechanism cannot be actuated any other way). Any module port having an ACBM can, however, be adapted for docking. The adapter simply has to incorporate a PCBM on the inner end. See, for example, PMA1 and PMA2.Not fred999 (talk) 20:53, 26 August 2017 (UTC)

Active vs. Passive

If anyone has better sources on the active and passive ports of the components, please add them. --TheDJ (talk • contribs) 14:24, 19 June 2007 (UTC)

A picture?

A photo or a drawing of the Common Berthing Mechanism would really be nice. Supermagle 08:37, 31 August 2007 (UTC)

Yes, agreed. N2e (talk) 15:27, 19 October 2010 (UTC)

I have added a schematic diagram of the CBM that was recently added to Commons. N2e (talk) 18:10, 4 March 2011 (UTC)

Time context

When was the CBM first used on the ISS? Were CBMs extant on the earliest space station modules launched in 1998/99? Or were they only added later as berthing adapters to the early APDS docking ports on the US segments of the station? In any event, the article would be improved if it explicated the time element in a History section or in the existing prose. Cheers. N2e (talk) 16:52, 4 March 2011 (UTC)

Specifications

Does anyone have a source for the specs for this device?

• How large is it?
• What can pass through its opening, dimensionally?
• How much mass does the CBM add to a spacecraft when bolted on? Is it the same for both sides of the mechanism?
• How fast can a berthing be accomplished? (I understand informally that the process of bolting the thing up to seal it is necessarily a very slow process to allow full thermal equilibrium on both sides of the connection, before some large number of screws are tightened up to apply the requisite mechanical force to hold the two sides together.)

And what about IP concerns

• Does NASA, ESA, or whomever freely license it to other space entities, whether government (e.g., China, Russia, India) or commercial (e.g., Bigelow Aerospace, Boeing, SpaceX)?

Cheers. N2e (talk) 19:53, 28 August 2011 (UTC)

I have updated the description to reference the Development Specifications and to correct a misconception about the hatch, which is not part of either half. In some installations of the PCBM (in particular) there is, in fact, neither hatch nor berthing plate (e.g., Cupola, Z1 Truss, PMA1, PMA2).Not fred999 (talk) 20:50, 26 August 2017 (UTC)

Some more detail on hatch options would be helpful - especially for the ACBM - It looks like the active mechanism (the 4 Controller Panel Assemblies) obstruct the 50" circular bore, how is that avoided ? - Rod57 (talk) 16:17, 24 August 2018 (UTC)

As noted above, the hatch is not part of any CBM, so there are no "options" in that regard. The 4 Controller Panel Assemblies, which are cantilevered inboard from the Berthing Plate Hatch Beam, are removed after berthing (IVA) in order to clear the 50" passageway. The "Berthing Plate" is part of the module, rather than part of the CBM. It may also prove useful to understand that all CBM's are "make on assembly" (that is, "on assembly of the module to which they are attached"). They never exist as a completed, stand-alone sub-assembly. Both ACBM and PCBM can, however, exist as a "kit" of parts. Not fred999 (talk) 16:47, 6 October 2018 (UTC)

Quality and valuable pictures of the CBM

http://www.spaceflight.nasa.gov/gallery/images/station/crew-32/html/iss032e026317.html

--Craigboy (talk) 16:47, 16 December 2012 (UTC)

Info and research

Apparently it was being developed for Space Station Freedom.

This document from March 1990 states "The “common” berthing mechanism appears in three forms: active rigid, passive rigid, and passive flexible as shown in Figures 8 and 9. The design and development of these mechanism are significant to both the NASA work packages and the international partners who will be attaching their laboratories to the basic station configuration."

This document from November 1991 indicates that third configurations had been dropped. In this document it states it's being developed for Space Station Freedom.

--Craigboy (talk) 17:20, 16 December 2012 (UTC)

Full-Scale Engineering Development of the CBM began under one of the Space Station Freedom (SSF) contract Work Packages. It was completed under the International Space Station (ISS) contract after the NASA SSF contracts were novated to Boeing.

The third configuration was originally intended to "close" a loop comprised of several modules, so that a complete circuit could be traversed in a shirt-sleeve environment. The notion was problematic due to the aggregate of deflections induced by pressurization and thermal conditions. These deflections, which were substantial in comparison to the capability of the large-diameter seals at the CBM/CBM interface, were difficult to predict given the tools available at the time. Not fred999 (talk) 04:34, 3 March 2013 (UTC) not_fred999;

Price, suppliers, Use in BEAM

Bigelow_Expandable_Activity_Module used one - presumably the Passive version (since it went into an Active CBM (Harmony-Nadir)). That article says "Sierra Nevada Corporation built the $2 million Common Berthing Mechanism under a 16-month firm-fixed-price contract " The Active CBM seems much more complicated (4 CPAs etc) - what do they cost ? Who else builds ACBMs and PCBMs ? - Are the designs freely licenced eg by NASA ? - Rod57 (talk) 16:22, 22 August 2018 (UTC)

What torque can it bear

What torque can the CBM bear in twisting and bending modes ? - Rod57 (talk) 16:03, 22 August 2018 (UTC)

That depends...the actual issue is "combined loads". The "simple" version of the question is "what load cases were used as development requirements?", but that isn't quite the same as "what will it bear?". Not trying to dodge the question...it just isn't answerable exactly as asked. Not fred999 (talk) 17:20, 4 October 2018 (UTC)

Operations

Adding an operations section is a very good idea. With a little work, I might be able to dig up some verifiable references on this general topic.

The M/D Covers (including the "petals") exist on radial ports, only.

The pre-berth alignment process makes every attempt to _avoid_ use of the alignment guides, because such contact introduces significant loads into the RMS (which is basically a damp noodle). The loads can render the operation extremely difficult to control. The alignment guides were actually designed to serve as "bumpers" rather than as "guides", per se. Their driving issue was mitigation of the potential for galling due to excessive contact stresses (a Nitronic-60 contact edge riveted to a Titanium "blade"). The same driving issue was behind the design of the "cow horns and rails" for radial port installations.

As originally Qualified per the referenced specifications, the capture process isn't complete until the first pass of bolt-up has occurred. Thermal hold is generally required only when one of the elements has low thermal mass and, when it does occur, is imposed after that first pass. Although I've not paid attention to that issue for several years, I don't believe it happens very often.

While strain gauges _are_ involved, it is more informative to refer to the characteristic as a "load cell". The unit undergoes extensive in-situ calibration during the manufacturing process.

When/as/if I'm able to recover definitive references for the above, I'll add them to the basic page. Until then, it's just...talk. (See what I did, there?) Not fred999 (talk) 17:34, 4 October 2018 (UTC)

Added a tabulation of uses during assembly and resupply. After carefully reading through the Wikipedia standards, I doubt if much additional detail can be added. For example, the specifications run to 373 pages in total; pretty much any extraction or summarization of the requirements therein constitutes "synthesis" because of the potential for POV errors (or the appearance thereof). There are very few true "secondary" sources available on the topic of CBM. Most of the "primary" sources (of which I have several at my disposal) are a class of documentation for which specialized knowledge is required to see that "independence" is actually a feature. Most likely, I need to remove some of my earlier edits to comply with the stated goal of being "tertiary". It is, in fact, likely that the sources used for the table also don't meet the criteria precisely as written, but they're comparable to those used in related articles, so I dropped it in. The two newly-referenced NASA/JSC documents are actually primary sources (per the formal definition), since they don't uniformly reference anything other than the experience and expertise of the authors. For those reasons, I've omitted several thousand words of other tidbits. I'll publish them "elsewhere" online, so the effort isn't completely wasted. Good luck, y'all!Not fred999 (talk) 00:40, 24 November 2018 (UTC)

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