Common Berthing Mechanism (CBM)

The Common Berthing Mechanism (CBM), designed and built by Boeing, is the primary means for connecting the pressurized portions of the International Space Station (ISS) together. The two CBM rings, one active on the ISS and one passive on the payload to be connected, join together to provide an airtight seal between them. The berthing is accomplished by having the RMS (either Shuttle SRMS or ISS SSRMS) place the payload within a few inches of an ISS berthing port, then commanding the CBM latches to capture their opposing fittings and pull the two rings together. Alignment guides, bumpers, and pins align the two rings rings together during the berth, while bolts are applied after latch completion to provide the airtight seal.

Dynamic Concepts, Inc. has supported the CBM project in the areas of contact dynamics and loads analysis. The primary purpose has been to determine the berthing loads that are applied to the RMS grapple fixtures as well as the ISS and/or Shuttle. During the early phases of CBM development and deployment on the ISS, DCI supported CBM hardware testing in the MSFC Contact Dynamics Simulation Laboratory (CDSL) as well as in the MSFC Evironmental Test Facility (ETF). DCI has also supported the development of a comprehensive dynamic and contact simulation model of the CBM for use in pre-flight loads detemination. In recent years DCI's CBM model has been ported into the JSC Systems Engineering Simulator (SES) simulation as well as the Canadian Space Administration's (CSA) SPOTS simulation, which are used prior to each flight supporting a CBM berth to investigate potential loads problems.