1、Best Practices Entry: Best Practice Info:a71 Committee Approval Date: 2000-04-18a71 Center Point of Contact: GSFCa71 Submitted by: Wil HarkinsSubject: Qualification of Nonstandard Electrical, Electronic, and Electromechanical (EEE) Parts in Spaceflight Applications Practice: The source for selection
2、 of acceptable flight quality EEE parts for use on Goddard projects is the GSFC Preferred Parts List (PPL-20) (Reference 2). PPL-20 complements NASA Standard Electrical, Electronic, and Electromechanical (EEE) Parts List (NSPL) (MIL-STD-975) (Reference 1) by listing additional part types and part ca
3、tegories not included in MIL-STD-975. Recognizing that it is neither possible nor desirable to include all parts in the GSFC PPL and in the NSPL, the GSFC parts requirements make provision that limited numbers of parts not included in the PPL or the NSPL may be used if it is demonstrated that the pa
4、rts are acceptable (Reference 5, section 5). The acceptability of nonstandard parts is enhanced by use of the part procurement specifications provided in Appendix E of PPL-20. The acceptability of these nonstandard parts must be demonstrated prior to commitment to design or use. Requests for approva
5、l to use nonstandard parts with supporting documentation are forwarded to the appropriate GSFC Project Office for review and approval. The practice described herein is used for demonstrating and documenting the acceptability of nonstandard parts for space flight use.Programs that Certify Usage: GFSC
6、 spaceflight projects approve the use of nonstandard parts on a per case basis.Center to Contact for Information: GSFCImplementation Method: This Lesson Learned is based on Reliability Practice number PT-TE-1418 from NASA Technical Provided by IHSNot for ResaleNo reproduction or networking permitted
7、 without license from IHS-,-,-Memorandum 4322A, NASA Reliability Preferred Practices for Design and Test.Benefit:The practice of using approved nonstandard parts that have been appropriately demonstrated to be acceptable for the applications provides for a wider range of parts selection than are ava
8、ilable with standard parts. These parts are at a quality level equal to that of Grades 1 or 2 standard parts.Implementation Method:Any EEE part that does not meet the criteria of a NASA Standard Part by being listed in the NASA Standard Parts List (NSPL) or the Preferred Parts List (PPL) is a nonsta
9、ndard part that must be reviewed and accepted prior to use. It is the responsibility of the activity selecting the nonstandard part to demonstrate acceptability of the part prior to committing it to a design. Contractors document and approve their selection, application, evaluation, and acceptance c
10、riteria for nonstandard parts on a GSFC Form 4-15 (see Figures 1 & 2), Nonstandard Parts Approval Request (NSPAR)(Reference 5). The NSPAR forms are forwarded to the GSFC Project Office for review and GSFC approval. Figure 3 depicts the process flow of the nonstandard parts approval process.Provided
11、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-refer to D descriptionD Figure 1: Nonstandard Part Approval Request (NSPAR)/GSFC Form 4-15Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-refer to D descriptionD
12、 Figure 2: Nonstandard Part Approval Request/ GSFC Form 4-15 (Second Page)Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-refer to D descriptionD Figure 3: Nonstandard Part Approval Process FlowProvided by IHSNot for ResaleNo reproduction or networki
13、ng permitted without license from IHS-,-,-Nonstandard Parts Specifications:Nonstandard parts must be at a quality level equal to that of Grade 1 or 2 standard parts and are procured in accordance with military, NASA, or contractor controlled specifications prepared in accordance with MIL-STD-490. Sp
14、ecifications for nonstandard parts are equal to the requirements of the nearest applicable standard part.Specifications and drawings fully identify the item being procured and include the physical, electrical, and environmental test requirements and quality assurance provisions including parts scree
15、ning necessary to control manufacturing and acceptance. Specifications also describe marking, handling, packaging, storage of parts and the criteria for testing of parts taken from storage, and address environmental controls for temperature, humidity, particulate contamination, and controls for elec
16、trostatic discharge (ESD) for parts which are susceptible to ESD damage.Parts Qualification and Quality Conformance Inspection:Nonstandard parts have qualification bases traceable to test and inspection data at the part level in a manner consistent with the specification requirements of the nearest
17、standard parts. The qualification is based on parts which have been produced by the same manufacturer using the same manufacturing technology as the nonstandard parts for which approval is being sought. Nonstandard parts undergo quality conformance inspection consistent with the specification requir
18、ements of the nearest standard parts.Hybrid Microcircuits:Hybrid microcircuits that are not included in the NSPL or the PPL are subject to nonstandard parts control. Their selection and approval is consistent with the requirements of MIL-H-38534B, General Specification for Microcircuits.Additional P
19、arts Requirements Applicable to Nonstandard Parts:The following additional requirements pertain to nonstandard parts as applicable: Derating, Radiation Hardness, Screening Verification Tests, Destructive Physical Analyses, and Parts Identification List (Reference 5).Technical Rationale:The competent
20、 selection and acceptance of the proper EEE Parts for spaceflight use is an essential part of design of spacecraft hardware. With the rapidly growing availability of EEE parts that perform major system functions, the selection of parts has become a mainstream activity of electronic design. Further,
21、the assurance that the selected part will perform reliably in the Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-application, whether it be a small component with a limited mission life or an entire spacecraft with a long expected lifetime, continue
22、s to be a primary engineering responsibility.References:1. NASA Standard Electrical, Electronic, and Electromechanical Parts List, MIL-STD-975 (NSPL)2. GSFC Preferred Parts List (PPL)3. MIL-STD-490, Specification Practices4. MIL-H-38534B, General Specification for Hybrid Microcircuits5. Guidelines f
23、or Standard Payload Assurance Requirements (SPAR) for GSFC Orbital ProjectsImpact of Non-Practice: Noncompliance with the use of NASA qualified parts would result in the use of unqualified and untested parts in spaceflight hardware. These unqualified parts could result in marginal performance and fa
24、ilure to perform in or survive the environmental exposure of space.Related Practices: N/AAdditional Info: Approval Info: a71 Approval Date: 2000-04-18a71 Approval Name: Eric Raynora71 Approval Organization: QSa71 Approval Phone Number: 202-358-4738Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
