The Office of Safety and Mission Assurance (OSMA) is preparing to submit NASA-STD-8739.14, NASA Fastener Procurement, Receiving Inspection, and Storage Practices for NASA Mission Hardware for agencywide review in order to meet the planned May 6, 2020, publication date.
NASA-STD-8739.14 is the new document number for what used to be NASA-STD-6008, NASA Fastener Procurement, Receiving Inspection, and Storage Practices for Spaceflight Hardware. This is the first substantive technical change to the document since its stewardship transferred from the NASA Office of the Chief Engineer to the NASA Office of Safety and Mission Assurance in 2008. The number change aligns with OSMA’s assigned number series for technical standards.
The organization of the document was changed to align more consistently with the production life cycle, which is also reflected in the title. The forward and applicability statements were changed to decouple the standard from the requirements for invoking it. NPD 8730.5B, NASA Quality Assurance Program Policy and the future NPR 8735.2C, Management of Government Quality Assurance Functions for NASA Contracts establish that the fastener standard is an element of the agency’s baseline Quality policy. Decoupling technical requirements from when the standard will be used reduces confusion for programs and projects that may tailor out or tailor in the standard, or parts of the standard.
The applicability statements and some specific requirements expanded the applicability to fasteners used in aircraft. The title wording changed “Spacecraft” to “Mission” to accommodate this increase in scope. The language used differentiates between requirements that apply to common fasteners used to install experiment payloads into aircraft and fasteners specifically designed by aircraft Original Equipment Manufacturers (OEMs). Fasteners obtained from military depots are exempt from the standard because Quality Assurance (QA) of these fasteners is provided by the military depot and they are received as a “known good.” When this standard is used, all acquired fasteners, whether for use in aircraft or space missions, are subject to counterfeit avoidance requirements. Fasteners contained in delivered Commercial-off-the-Shelf items are not within the scope of the standard.
It is expected that the processes set up for meeting the standard’s requirements are institutionalized and included in the center or OEM’s Quality Management System rather than created each time by programs or projects. Most NASA centers already do this.
The standard can be used for in-house production or can be cited on a contract. Wording was changed to encourage programs and projects to use a compliance matrix approach to evaluate OEMs’ fastener QA) process traceability to the standard rather than requiring the supplier to generate a fastener control plan. A plan is required that describes how fasteners manufactured to source control drawings are determined to meet mechanical performance requirements.
Technical requirements were removed or changed to create clarity and reduce duplication with other technical standards. Requirements that drive design selections were removed because they are addressed by NASA-STD-5019, Fracture Control Requirements for Spaceflight Hardware. Requirements that instructed how to select fasteners for a design or how materials engineers execute processes defined in NASA-STD-6016, Standard Materials and Processes Requirements for Spacecraft were removed.
Criticality levels are used to align the design criticality with sufficient QA criteria. The criticality levels are traceable to those used in NASA-STD-5019. Both fracture-critical and non-fracture critical low-risk types are now treated as the same assurance category.
The criteria and requirements for selecting a qualified or unqualified supplier were modified. For qualified suppliers, AS9003, Inspection and Test Quality Systems Requirements for Aviation, Space, and Defense Organizations is listed as an acceptable alternative to AS9100, Quality Management Systems – Requirements when compliance to that standard is established by a third party. The suppliers associated with the products on the Defense Logistics Agency’s Qualified Supplier List for fasteners are also recognized as qualified. Reference to a NASA-approved supplier list was removed, as there is no longer such a list.
Language was simplified and clarified as it pertains to traceability, material test reports, and records delivery and retention. All of the incoming tests and inspections were summarized in a single table with columns dedicated to each criticality class and whether the supplier is qualified or unqualified. Clarifications are given for quantitative or semi-quantitative chemical tests to avoid disagreements about the results of qualitative chemical tests. Chemical analysis requirements were increased for non-fracture critical fail-safe rated (Category II) fasteners in the interest of counterfeit avoidance. Hardness testing is no longer allowed as a substitute for tensile testing for short fasteners (too short for hardness testing). It is recognized that procurements through qualified suppliers resolves the tensile testing problem for short fasteners.
Sample sizes for quality conformance tests were aligned with the ASTM F1470 standard, with a minimum of two samples for small lots. Sample sizes are increased when lots lack traceability. Sample sizes are similar for small lots regardless of the use of qualified or unqualified suppliers. For large lots from unqualified suppliers, the sample sizes were increased.
Visual inspection magnification is now per the criteria contained in the fastener part specification. Dimensional verification is used only for threaded fasteners and ASME B1.3, System 22 is required for the most critical fasteners: Category I. System 22 or 21 can be used for Categories II and III.
A PowerPoint overview of the changes from NASA-STD-6008 to NASA-STD-8739.14 can be found in the Documents section on the Quality discipline page.