PAYLOAD VIBROACOUSTIC TEST CRITERIA
|Publication Date:||7 November 2017|
The term "vibroacoustics" is defined as an environment induced by high-intensity acoustic noise associated with various segments of the flight profile. Vibroacoustics manifests itself throughout the payload in the form of transmitted acoustic excitation and as structure-borne random vibration. This NASA Technical Standard specifically addresses the acoustic and random vibration environments and test levels.
This NASA Technical Standard establishes the uniform use of test factors in the vibroacoustic verification process for spaceflight payload hardware. This NASA Technical Standard provides test factors for verification of payload hardware for qualification, protoflight, and flight acceptance programs. In addition, minimum workmanship test levels are included. With the exception of minimum workmanship test levels, these levels are provided in relation to the maximum expected flight level (MEFL). Although the major emphasis of this NASA Technical Standard is on test levels, it also covers test duration, test control tolerances, data analysis, test tailoring, payload fill effects, and analysis methods.
This NASA Technical Standard defines procedures for developing vibroacoustic test criteria for NASA payloads. This document also presents methods for acceptance and qualification vibroacoustic testing, for statistical analysis of vibroacoustic data, and analysis methods for determining criteria. Minimum acoustic and random vibration workmanship test levels are specified. This NASA Technical Standard only applies to NASA payloads and payload components and is not retroactive to the approval date of this NASA Technical Standard.
This NASA Technical Standard recommends engineering practices for NASA programs and projects. The levels and methods set forth herein form the basis for developing project-specific requirements for all new payload projects.
This NASA Technical Standard is approved for use by NASA Headquarters and NASA Centers and Facilities and may be cited in contract, program, and other Agency documents as a technical requirement. It may also apply to the Jet Propulsion Laboratory (JPL) and other contractors only to the extent specified or referenced in applicable contracts.
Verifiable requirement statements are designated by PVTR (Payload Vibroacoustic Test Requirement), numbered, and indicated by the word "shall"; this NASA Technical Standard contains 73 requirements. Explanatory or guidance text is indicated in italics beginning in section 4. To facilitate requirements selection and verification by NASA programs and projects, a Requirements Compliance Matrix is provided in Appendix D.
This NASA Technical Standard applies only to spaceflight payload hardware. Launch vehicles, payloads launched by sounding rockets, aircraft and balloons, and ground support equipment (GSE) are excluded. This NASA Technical Standard does not apply to payload programs approved prior to the date of this document. This NASA Technical Standard is applicable principally to Classes A, B, and C payloads.
Classification of NASA payloads is defined in NPR 8705.4, Risk Classification for NASA Payloads.
For Class D payloads, NASA-STD-7001 is a guidance document. Class D payloads may utilize tailoring as stated in section 4.4.6.
The levels of assembly for which the NASA Technical Standard is applicable are the payload, subsystem, and component levels as specifically identified or as judged to be appropriate (refer to definitions in section 3.2). This NASA Technical Standard is applicable to the full range of payload hardware programs, including prototype, protoflight, follow-on, spare, and reflight.
Some discussion of analytical methods used as an aid to develop requirements is presented in Appendix B. The applicability and limitations of the methods are discussed. A brief description of vibroacoustic loads is described in Appendix C; for more detail, see NASASTD- 5002, Load Analyses of Spacecraft and Payloads.
Verification programs which meet or exceed the mandatory requirements for vibroacoustic testing set forth in this NASA Technical Standard are considered compliant with this NASA Technical Standard.