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International Space Station Powered Bolt Nut Anomaly and Failure Analysis SummaryA key mechanism used in the on-orbit assembly of the International Space Station (ISS) pressurized elements is the Common Berthing Mechanism. The mechanism that effects the structural connection of the Common Berthing Mechanism halves is the Powered Bolt Assembly. There are sixteen Powered Bolt Assemblies per Common Berthing Mechanism. The Common Berthing Mechanism has a bolt which engages a self aligning Powered Bolt Nut (PBN) on the mating interface (Figure 1). The Powered Bolt Assemblies are preloaded to approximately 84.5 kN (19000 lb) prior to pressurization of the CBM. The PBNs mentioned below, manufactured in 2009, will be used on ISS future missions. An on orbit functional failure of this hardware would be unacceptable and in some instances catastrophic due to the failure of modules to mate and seal the atmosphere, risking loss of crew and ISS functions. The manufacturing processes that create the PBNs need to be strictly controlled. Functional (torque vs. tension) acceptance test failures will be the result of processes not being strictly followed. Without the proper knowledge of thread tolerances, fabrication techniques, and dry film lubricant application processes, PBNs will be, and have been manufactured improperly. The knowledge gained from acceptance test failures and the resolution of those failures, thread fabrication techniques and thread dry film lubrication processes can be applied to many aerospace mechanisms to enhance their performance. Test data and manufactured PBN thread geometry will be discussed for both failed and successfully accepted PBNs.
Document ID
20100021933
Document Type
Conference Paper
Authors
Sievers, Daniel E. (Boeing Co. Huntsville, AL, United States)
Warden, Harry K. (Boeing Co. Huntsville, AL, United States)
Date Acquired
August 29, 2013
Publication Date
May 12, 2010
Publication Information
Publication: Proceedings of the 40th Aerospace Mechanisms Symposium
Subject Category
Space Sciences (General)
Distribution Limits
Public
Copyright
Public Use Permitted.

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IDRelationTitle20100021914Analytic PrimaryProceedings of the 40th Aerospace Mechanisms Symposium