1、APPROVED FOR PUBLIC RELEASEDISTRIBUTION IS UNLIMITED NASA TECHNICAL STANDARD NASA-STD-7003A National Aeronautics and Space Administration Approved: 12-20-2011 Washington, DC 20546-0001 Superseding NASA-STD-7003 PYROSHOCK TEST CRITERIA MEASUREMENT SYSTEM IDENTIFICATION: METRIC/SI (ENGLISH) Provided b
2、y IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NASA-STD-7003A APPROVED FOR PUBLIC RELEASEDISTRIBUTION IS UNLIMITED 2 of 41 DOCUMENT HISTORY LOG Status Document Revision Approval Date Description Baseline 08-18-1999 Initial Release Revision A 12/20/2011 See de
3、scription below: Significant changes were made to the document. It is recommended that the document be reviewed in its entirety before implementation. Key changes include, but are not limited to, the following: - Incorporated document into the Endorsed Standards template. - Added summary of “shall”
4、statements in section 1.6. - Made various changes throughout document for clarification and to reflect current and updated state-of-the-art references. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NASA-STD-7003A APPROVED FOR PUBLIC RELEASEDISTRIBU
5、TION IS UNLIMITED 3 of 41 FOREWORD This Standard is published by the National Aeronautics and Space Administration (NASA) to provide uniform engineering and technical requirements for processes, procedures, practices, and methods that have been endorsed as standard for NASA programs and projects, in
6、cluding requirements for selection, application, and design criteria of an item. This Standard is approved for use by NASA Headquarters and all NASA Centers, including Component Facilities and Technical and Service Support Centers. This Standard establishes a methodology for developing pyroshock tes
7、t criteria for NASA spacecraft, payload, and launch vehicle hardware for development, qualification, flight acceptance, and/or protoflight test verifications. The state-of-the-art for pyroshock prediction, design and test verification has not yet reached the maturity of other environmental disciplin
8、es due to the complex, high-frequency nature of pyroshocks. However, recent advances in the measurement and analysis of pyroshocks have led to a better understanding of this environment. Requests for information, corrections, or additions to this Standard should be submitted via “Feedback” in the NA
9、SA Standards and Technical Assistance Resource Tool at http:/standards.nasa.gov. Original Signed By: 12/20/2011 _ _ Michael G. Ryschkewitsch Approval Date NASA Chief Engineer Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NASA-STD-7003A APPROVED FOR
10、 PUBLIC RELEASEDISTRIBUTION IS UNLIMITED 4 of 41 SECTION TABLE OF CONTENTS PAGE DOCUMENT HISTORY LOG . 2 FOREWORD . 3 TABLE OF CONTENTS . 4 LIST OF FIGURES . 6 LIST OF TABLES . 6 1. SCOPE . 7 1.1 Purpose 7 1.2 Applicability 7 1.3 Tailoring 8 1.4 Background . 8 1.4.1 Pyrotechnic Applications 8 1.4.2
11、Pyroshock Characteristics 8 1.4.3 Potential Hardware Effects 9 1.5 Summary of Pyroshock Level of Assembly and Environmental Categories . 9 1.6 Summary of Pyroshock Test Criteria . 9 2. APPLICABLE DOCUMENTS 12 2.1 General 12 2.2 Government Documents 12 2.3 Non-Government Documents . 13 2.4 Order of P
12、recedence 13 3. ACRONYMS, SYMBOLS, AND DEFINITIONS . 13 3.1 Acronyms and Abbreviations 13 3.2 Definitions . 14 3.2.1 Pyroshock 14 3.2.2 Pyrotechnic Source Categories . 14 3.2.3 Pyroshock Environmental Categories . 15 3.2.4 Pyroshock Environmental Parameters 15 3.2.5 Environmental Test Categories . 1
13、8 3.2.6 Level of Assembly Categories 18 4. REQUIREMENTS 19 4.1 Pyroshock Test Rationale 19 4.2 Maximum Expected Flight Environment 20 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NASA-STD-7003A APPROVED FOR PUBLIC RELEASEDISTRIBUTION IS UNLIMITED
14、5 of 41 SECTION TABLE OF CONTENTS, continued PAGE 4.3 Test Margins and Number of Applications . 20 4.4 Test Specifications 21 4.5 Test Methods and Facilities 23 4.6 Data Acquisition 25 4.7 Data Analysis 27 4.8 Test Control Tolerances 27 4.9 Test Article Operation . 27 4.10 Test Tailoring 28 APPENDIC
15、ES A Prediction of Pyroshock Environments 29 B Determination of Maximum Expected Flight Environment 36 C Guidance . 39 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NASA-STD-7003A APPROVED FOR PUBLIC RELEASEDISTRIBUTION IS UNLIMITED 6 of 41 FIGURE
16、LIST OF FIGURES PAGE 1 Typical Far-Field Pyroshock Acceleration Time History and Maximax Shock Response Spectrum . 17 2 Typical Near-Field Acceleration Time History and Positive and Negative Shock Response Spectrum . 17 3 Peak Pyroshock Response versus Distance from Pyrotechnic Source 34 4 Correctio
17、n of Shock Response Spectrum for Distance from Pyrotechnic Source . 35 TABLE LIST OF TABLES PAGE 1 Summary of Pyroshock Test Margins 10 2 Tolerance Factors for P95/50 Normal Tolerance Limit 38 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NASA-STD-
18、7003A APPROVED FOR PUBLIC RELEASEDISTRIBUTION IS UNLIMITED 7 of 41 PYROSHOCK TEST CRITERIA 1. SCOPE 1.1 Purpose The purpose of this Standard is to provide a consistent methodology for developing pyroshock test criteria for NASA spacecraft, payload, and launch vehicle hardware during the development,
19、 qualification (Qual), flight acceptance (FA), and/or protoflight (PF) test phases of the verification process. Various aspects of pyroshock testing are discussed herein, including test environments, methods and facilities, test margins and number of exposures, control tolerances (when applicable),
20、data acquisition and analysis, test tailoring, dynamic analysis, and prediction techniques for pyroshock environments. The most accurate simulation of the flight pyrotechnic environment is obtained for potentially susceptible hardware by testing with flight pyrotechnic devices on actual or closely s
21、imulated flight structure. However, high-fidelity flight structure is not usually available early in a program, and this approach does not provide magnitude qualification margin over flight. The alternative approach described in this Standard is to perform qualification or protoflight pyroshock simu
22、lation tests on potentially susceptible flight or flight-like hardware assemblies as early as possible, then to activate actual pyrotechnic devices on the flight system to improve pyroshock environment predictions and as a final verification. The advantages of this approach are that it may reveal po
23、tential hardware deficiencies early in the development program, and it allows the application of a qualification/protoflight margin to assembly-level pyroshock tests. The disadvantages include the potential for incorrect estimates of the pyroshock environment due to limitations of measurement method
24、s and analysis techniques available today and the difficulty in accurately simulating a specified pyroshock environment at the assembly level. Regardless, testing on actual or closely similar flight structures is essential for final system verification. 1.2 Applicability This Standard is applicable
25、to the development of pyroshock test criteria for NASA spacecraft, payload, and launch vehicle hardware during the development, qualification, flight acceptance, and/or protoflight test phases of the verification process. Verification programs that meet or exceed the endorsed requirements for pyrosh
26、ock testing set forth in this document shall be considered compliant with this Standard. Shock testing requirements for hardware utilized in Range Safety Systems, and the methodology for tailoring those requirements for a specific program, are contained in Air Force Space Command Manual 91-710 (AFSP
27、CMAN91-710). The Range has specific requirements for margins, minimum test levels, number of shock applications during testing, test tolerances, and testing unique to shock isolators. This Standard is approved for use by NASA Headquarters and NASA Centers, including Provided by IHSNot for ResaleNo r
28、eproduction or networking permitted without license from IHS-,-,-NASA-STD-7003A APPROVED FOR PUBLIC RELEASEDISTRIBUTION IS UNLIMITED 8 of 41 Component Facilities and Technical and Service Support Centers, and may be cited in contract, program, and other Agency documents as a technical requirement. T
29、his Standard may also apply to the Jet Propulsion Laboratory or to other contractors, grant recipients, or parties to agreements only to the extent specified or referenced in their contracts, grants, or agreements. Requirements are numbered and indicated by the word “shall.” Explanatory or guidance
30、text is indicated in italics beginning in section 4. 1.3 Tailoring Tailoring of this Standard for application to a specific program or project shall be formally documented as part of program or project requirements and approved by the Technical Authority. 1.4 Background 1.4.1 Pyrotechnic Application
31、s Current launch vehicle, payload, and spacecraft designs often utilize numerous pyrotechnic devices over the course of their missions. These devices are generally used to separate structural subsystems (e.g., payloads from launch vehicles), deploy appendages (e.g., solar panels), and/or activate on
32、-board operational subsystems (e.g., propellant valves). 1.4.2 Pyroshock Characteristics The initial pyroshock peak acceleration may be as high as 200,000 g with high frequency content as high as 1 MHz; these derived characteristic values are highly dependent on the method of measurement and recordi
33、ng as well as the subsequent digital data analysis. The pyroshock acceleration time history has a short duration (less than 20 ms) and is also largely dependent on the source type and size or strength, intervening structural path characteristics (including structural type and configuration, joints,
34、fasteners and other discontinuities) and distance from the source to the response point of interest. Because of the high frequency content, many hardware elements and small components are susceptible to pyroshock failure while resistant to a variety of lower frequency environments, including random
35、vibration. High frequencies may make analytical methods and computational procedures inapplicable for system verification under pyroshock loading. a. Pyroshock verification shall be accomplished by Qual and FA or PF testing. b. Successful pyroshock testing shall be considered essential to mission su
36、ccess. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NASA-STD-7003A APPROVED FOR PUBLIC RELEASEDISTRIBUTION IS UNLIMITED 9 of 41 1.4.3 Potential Hardware Effects Many flight hardware failures have been attributed to pyroshock exposure, some resulti
37、ng in catastrophic mission loss (Moening, C.J. (1984). Specific examples of pyroshock failures include cracks and fractures in crystals, ceramics, epoxies, glass envelopes, solder joints and wire leads, seal failure, migration of contaminating particles, relay and switch chatter and transfer of stat
38、e, and deformation of very small lightweight structural elements, such as microelectronics. On the other hand, deformation or failure of major structural elements is rare except in those regions close to the source where structural failure is intended. 1.5 Summary of Pyroshock Level of Assembly and
39、Environmental Categories The pyroshock environment for most assemblies is externally-induced, thus assembly level pyroshock qualification is usually performed using a simulated pyroshock source that includes a 3 dB margin over the maximum expected flight environment. (See section 3.2.6 for a detaile
40、d discussion of externally-induced and self-induced shocks.) For the purposes of selecting the appropriate simulated shock test method, this Standard divides the pyroshock environment into the following three categories, depending on the shock severity and frequency range, as follows: First, near-fi
41、eld; second, mid-field; and third, far-field. Detailed definitions are provided in section 3.2.3. The intent of this categorization is to assist hardware and test personnel in the selection of appropriate test techniques and facilities. For the near-field, generally only pyrotechnic devices should b
42、e used. For the mid-field, either mechanical impact or pyrotechnic devices should be used. For the far-field, electrodynamic shakers, impact or pyrotechnic devices may be used. The pyroshock environment for most spacecraft systems, many large subsystems, and occasionally some assemblies are self-ind
43、uced. Self-induced shocks are simulated using the actual pyro device and flight or flight-like intervening structure. This Standard requires 3 dB margin (or 1.4 x maximum expected flight environment (MEFE) for qualification for pyroshock environments; but if the actual hardware and pyro devices are
44、used, then it will not be possible to achieve the 3 dB margin (or 1.4 x MEFE). Consequently, multiple firings of actual pyro devices and instrumentation of potentially shock sensitive components contained in the test article are required to validate lower level pyroshock test specifications. 1.6 Sum
45、mary of Pyroshock Test Criteria A summary of the mandatory requirements is given in this section. Mandatory pyroshock test margins are summarized in table 1. Specific pyroshock test requirements are selected based on the following: a. The flight or service pyroshock environment as defined in section
46、 3.2.3. b. The environment test categories described in section 3.2.5. c. The level of assembly defined in section 3.2.6. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NASA-STD-7003A APPROVED FOR PUBLIC RELEASEDISTRIBUTION IS UNLIMITED 10 of 41 d.
47、The MEFE as specified in section 4.2. e. Test margins as discussed in section 4.3. f. Test specifications described in section 4.4. g. The test method and facility as outlined in section 4.5. 1.6.1 If there is a question about the hardware susceptibility to pyroshock, then pyroshock testing shall be
48、 performed. (See section 4.1.1.) Table 1Summary of Pyroshock Test Margins Pyroshock Type Qualification Protoflight Flight Acceptance Self-Induced/Actual Device 2 Actuations 2 Actuations 1 Actuation Externally-Induced/Simulated MEFE + 3 dB MEFE + 3 dB MEFE 2x Each Axis 1x Each Axis 1x Each Axis 1.6.2 Pyroshock verification shall be accomplished by Qual and FA or PF testing. 1.6.2.1 Successful pyroshock testing shall be considered essential to mission success. (See section 4.1.2.1) 1.6.3 Pyrotechnic test criteria shall be based upon th
