Assembly Operations: Grapple, Berth, and Dock
NSTS 214921 identifies three legacy on-orbit operations of immediate interest: grappling, berthing, and docking. These three operations, from which most present-day concepts descend, can be abstracted as different mechanical means of one spacecraft asserting Control Authority2 over the trajectory and attitude of a cooperating spacecraft3: Footnotes “Payload Bay User’s Guide”, Johnson Space Center (2000)[↩] Used... read more
Capture Contact Dynamics
The movement of a chase vehicle (the “trajectory”) during a berthing event is dominated by several factors. These include the mass properties of the two elements, forces acting on the in-coming element by the item surrendering control authority, forces exerted by the CBM on the in-coming elements, and constraints deriving from the alignment structures of the... read more
CBM Flight Operations
A brief discussion of how the Common Berthing Mechanism is used in flight, along with a listing of operations on orbit. read more.
CBM Requirements
Release 2 on the CBM: a summary of the qualification requirements. Again, mostly for reference in future examples. Qualification Requirements of the Common Berthing Mechanism More to come.
Common Berthing Mechanism
Introduction The Common Berthing Mechanism (CBM) is a structural/mechanical device that connects pressurized elements within the US Orbital Segment of the International Space Station (ISS). It is used during assembly operations, such as that shown in Figure 1, and resupply missions. Existing in two distinct “halves”, the CBM effects and removes the Primary Structural joint... read more
Common Berthing Mechanism Core Design Description
This article discusses the design of core characteristics of the CBM. In this context, “core” refers to the features that contribute directly to berthing and deberthing of Pressurized Elements. A detail-light description of these features can be found here. Ancillary features are discussed elsewhere. Overview The CBM design can be visualized as a pair of serrated rings... read more
Conceptual Design of the Common Berthing Mechanism
The International Space Station's Common Berthing Mechanism (CBM) is an electro-mechanical assembly used to mate modules on orbit. Although often referred to in the singular, the (CBM) actually operates as a single mechanism only in the process of being mated or demated. Depending on installed location, operations are effected by either 40 or 44 mechanical sub-assemblies, completed by a suite of sensors and controllers. The machine is described in abstract terms, serving as an introduction and overview for detailed descriptions found elsewhere on this site. read more.
Contact Mechanics Under High-Vacuum
The most basic characteristic of a mechanism is the relative motion of faying surfaces under load. Points, lines, and surfaces of contact are assessed by calculating deformations and the resulting contact stresses1. The objectives of the analysis are to 1) estimate the forces due to friction and 2) predict whether damage occurs2. Footnotes That is,... read more
Qualification Requirements of the Common Berthing Mechanism
Requirements of the International Space Station's Common Berthing Mechanism are described in detail. Many aspects of the associated rationale and implications are discussed. read more.