Development Testing and Subsequent Failure Investigation of a Spring Strut Mechanism

Author: Robertson, Brandon
Published: May 14, 2014.
Physical Description: 1 electronic document
Additional Creators: Staab, Lucas, Culberson, Michael, and Dervan, Jared

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Summary

Commodities are transferred between the Multi-Purpose Crew Vehicle (MPCV) crew module (CM) and service module (SM) via an external umbilical that is driven apart with spring-loaded struts after the structural connection is severed. The spring struts must operate correctly for the modules to separate safely. There was no vibration testing of strut development units scoped in the MPCV Program Plan; therefore, any design problems discovered as a result of vibration testing would not have been found until the component qualification. The NASA Engineering and Safety Center (NESC) and Lockheed Martin (LM) performed random vibration testing on a single spring strut development unit to assess its ability to withstand qualification level random vibration environments. Failure of the strut while exposed to random vibration resulted in a follow-on failure investigation, design changes, and additional development tests. This paper focuses on the results of the failure investigations including identified lessons learned and best practices to aid in future design iterations of the spring strut and to help other mechanism developers avoid similar pitfalls.

Other Subject(s)

Spacecraft Design, Testing and Performance

Collection

NASA Technical Reports Server (NTRS) Collection.

Note

Document ID: 20140010344.
M13-2989.
Aerospace Mechanisms Symposium; 14-16 May 2014; Baltimore, MD; United States.

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