File talk:PCBM Assembly.jpg

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Prior Publication: //www.ehdavis.engineering/Exegeses/common-berthing-mechanism-core-design-description/

References used to develop the image:

  1. S683-28943E “Passive Common Berthing Mechanism Critical Item Development Specification”, CAGE 3A768, October 7, 1998. Referred to in the notes as “the spec”.
  2. SSP-41004J “Common Berthing Mechanism to Pressurized Elements Interface Control Document Part 2”, National Aeronautics and Space Administration/Johnson Space Center, Houston, Texas (October 25, 2005). The ICD is authoritatively called by the spec as being applicable in its entirety. Referred to herein as “the ICD”.
  3. T683-13850-3, “Common Berthing Mechanism Assembly Qualification Test Report”, Boeing Defense and Space Group, Missiles and Space Division, Huntsville, AL (October 8, 1998). Referred to in the notes as “the AQT”.
  4. NSTS photographs of assembly and on-orbit operations in the National Archives (e.g., //catalog.archives.gov/search?q=common%20berthing%20mechanism&f.materialsType=photographsandgraphics). All NSTS photographs are now in the archives, including many previously published on neither the NASA website nor on the new Flikr feed. Where some specific photograph is referred to, a NASA photograph designator is used.
  5. ISS photographs of assembly and other on-orbit operations in the NASA collections (//www.flickr.com/photos/nasa2explore/). Where some specific photograph is referred to, a NASA photograph designator is used. Few, of the ISS Expedition photographs are available in the archives. Only a small fraction appear to have been published as yet on the Flikr feed.
  6. JSC-48503, “International Space Station ISS/Shttle Joint Operations Book”, National Aeronautics and Space Administration/Johnson Space Center Mission Operations Directorate, Operations Division (28 JUN 05), referred to in the notes as “Joint Ops”. See //www.nasa.gov/centers/johnson/pdf/123838main_iss_shuttle_joint_ops_book.pdf.
  7. JSC-48502-5A “International Space Station Assembly Operations Book ISS-5A (Final)”, National Aeronautics and Space Administration/Johnson Space Center Mission Operations Directorate, Operations Division, August 16, 2000. Referred to as “5A Assy Ops” below. See //www.spaceref.com/iss/ops/5A.Assembly.Ops.Final.pdf.
  8. Sievers, Daniel E. and Harry K. Warden, “International Space Station Powered Bolt Nut Anomaly and Failure Analyusis Summary, 40th Aerospace Mechanisms Symposium (2010). See NTRS(//ntrs.nasa.gov/search.jsp) record #201000321933. Referred to in the notes as “Sievers and Warden”.
  9. McLaughlin, Richard J., and William H. Warr, “The Common Berthing Mechanism (CBM) for International Space Station”, SAE (2001). Referred to in the notes as “Honeywell”. This paper is already available on Wikipedia.
  10. Zipay, John J, Karen S. Bernstein, Erica E. Bruno, Phillipe Deloo, Raymond Patin, “Structural Verification of the First Orbital Wonder of the World – The Structural Testing and Analysis of the International Space Station (ISS)”, National Aeronautics and Space Administration, Johnson Space Center, Houston TX (2011). See NTRS record #20110013394. Referred to in the notes as “Zipay”.
  11. JSC-48513-4A, “International Space Station Maintenance & Repair Group (MRG) In-Flight Maintenance Book ISS-4A” (2000), NASA Johnson Space Center, Mission Operations Directorate, Operations Division. See http://www.spaceref.com/iss/ops/4a.ifm.pdf. Referred to in the notes as “4A IFM”.

Notes

  1. The AQT identifies the spec as the source of requirements for which compliance is being verified, establishing its relevance. It identifies major components by nomenclature in Figure 2-1. That nomenclature was used to correlate with the qualification part numbers listed in Appendix B (“CBM ALQT Test Article Summary”) of the test report. The designs might (or might not) have been revised since qualification, so part numbers might have changed since that time (1998). No attempt has been made to reconcile current part numbers with those that were originally qualified.
  2. The part number for the bumper was ambiguously reported in the AQT. Two parts having that nomenclature were listed in Appendix B: 683-27905-1 and 683-27906-1. After an extensive search through flight photographs, the former part number was discovered to be prominently and legibly displayed on a feature of the Kibo radial port ACBM in s124e006464, having geometry consistent with ICD Figure 3.3.10-6.1. The later part number was, therefore, taken as applicable to the bumper on the PCBM by process of elimination.
  3. Critical dimensions of the PCBM structural ring are documented in several figures of the ICD.
    1. The height of the ring is found in ICD Figure 3.1.4.1-22 (and several other figures of the same document).
    2. The thickness, inner diameter and outer diameter of the lower (“inboard”) flange of the ring are shown in in Figure 3.3.2.1-10 of the ICD.
    3. The thickness of the PCBM outboard flange is found in Figure 3.3.10-12 of the ICD. The outboard flange diameter is found in Figure 3.3.7-1. The outboard flange’s inner diameter and powered bolt locations were taken from Figure 3.1.4.1-8.
    4. The PCBM gusset locations were taken from Figure 3.3.10-9 of the ICD. Their thickness is dimensioned in Figure 3.3.10-12.
    5. “Cut-outs” on the face of the outboard flange are evident in Figure 3.3.10-11 of the ICD, and on many flight photographs. The radial dimension and the depth were estimated from the referenced figure. The circumferential extents of the cutouts was observed in the photographs (e.g., s123e006141) to align with thermal stand-offs and alignment sockets, and have been approximated that way in this image. It was noted from the photographs that not all of the cutouts subtend the same angle of arc.
    6. Thickness of the vestibule wall on the PCBM ring is dimensioned on Figure 3.3.10-10 of the ICD.
  4. Clearance dimensions for the Alignment Guides are found in ICD Figures 3.1.4.1-1-1 and -2. They do not appear to be uniformly consistent with scaling from multiple flight photographs. “Artistic” license has been taken in the image to be more consistent with the photographs. Such liberties include, but are not limited to, the apparent difference in material (or finish) between two sections of each guide. The sections appear to be riveted together. See, for example, sts097-330-011 (//catalog.archives.gov/id/23215626) and several photographs from STS-123 EVA outfitting of the Kibo ACBM.
  5. The ICD located and provided the envelope for the Capture Latch Fitting in Figures 3.1.4.1-17 and -18. The relationship between the fitting and the gusset spacing depicted in -18 is inconsistent with flight photographs of the mated vestibule (e.g., STS092-354-019). Recalling that many of the ICD figures are merely envelopes, the subject image proportionally followed the offset shown in the flight photographs. The base part number can be partially verified in ISS020E038705, although the dash number appears to have obscured by wear.
  6. Envelopes for the Alignment Socket are defined in ICD Figure 3.3.10-2, and are clearly depicted in in Figure 2 (page 185) of the Joint Ops. The photograph is nearly a planform view, and the width of the outboard flange is reasonably discernible as a basis for estimation.
  7. The enveloping dimensions of the Thermal Standoff are shown on Figure 3.3.10-3 of the ICD. The standoffs are clearly depicted in many flight photographs (e.g., S124E006153) and in Figure 2 of the Joint Ops (page 185).
  8. Figure 1 of Sievers and Warden shows a cross-section of the Powered Bolt Nut. Details of the assembly were simplified into flanged right circular cylinders, very little of which can be seen in the subject image.
    1. Of the internal parts, only the tip of the encapsulated nut was modeled for the subject image. The diameter was estimated by back-calculation of the mating bolt ID from the equation in the abscissa label of Figure 5-7 of the AQT, given the values documented in section 5.2.2 thereof. The back-calculation was discovered late in image development. The encapsulated nut is slightly over-sized in the subject image. The difference is just slightly discernible at the scale of the subject image.
    2. The aspect ratio of the outboard flange in the Sievers and Warden does not compare well to cross-sections in the ICD: it appears to be longer in the radial direction than other cross-sections show. Only a few flight photographs appear to show how the bolts and their respective nuts mount on the back side of the outboard flange: see, in particular, STS097-330-011 and STS101-387-016, which clearly show that the two nut mounting bolts are not on a radius of the ring. Noting that Figure 1 of Sievers and Warden appears to show that it is radial, it seems safe to assume that the cross-section of that figure is, in fact, non-radial. The apparent aspect ratio of that figure was, therefore, disregarded for the subject image. The longitudinal proportions were accepted.
  9. The thickness of the molded seal’s substrate on the face of the PCBM was calculated from the stack height shown in ICD Figure 3.1.4.1-7, subtracting the station reference at the face of the flange in that same figure.
  10. The radially-distributed features across the face of the assembled ring and molded seal were estimated from Figures 2 and 3 of the Joint Ops (pages 185 and 186, respectively), given the nearby alignment socket features for which dimensions are given in ICD Figure 3.3.10-2 and the afore-mentioned back-calculation of the Powered Bolt Nut internal diameter.
  11. The widths of the molded seal beads were modeled as equal to the height reported in the Joint Ops. See Figure 2 of the reference on page 185. It is recognized that the height/width relationship of an o-ring is not necessarily applicable this type of seal, but the differences cannot be discerned at the scale of the subject image.
  12. The berthing plate and hatch were not modeled for this image for three reasons:
    1. The spec did not regard them as part of the CBM.
    2. The ICD describes the plate (in effect) as the thing an ACBM mounts to, and the hatch as plugging the hole in the plate. That is consistent with Zipay (see, in particular, Figures 2 and 3).
    3. The AQT describes them as part of the test fixture rather than as part of the test article.
  13. Flight photographs show a large assortment of grounding straps, brackets, and fasteners. None are pertinent to understanding the overall arrangement of the design. None were modeled.
  14. The IVA seals, not shown, are delivered to orbit in kit form. The kits include parts for the CBM/PE and CBM/CBM joints, spline locks and “butter dish” covers for the powered bolts, and ancillary pieces. See the 4A IFM, pages 98-128. The IVA seal land covers, also not shown, are delivered in place. See the 4A IFM, page 122, and numerous flight photographs.

Not fred999 (talk) 22:36, 29 February 2020 (UTC)[reply]

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