4.1.1 Materials and Processes Selection, Control, and Implementation Plan
- a. [MPR 9] Each organization that is responsible for the design and fabrication of spaceflight hardware shall provide a Materials and Processes Selection, Control, and Implementation Plan.
The Materials and Processes Selection, Control, and Implementation Plan documents the degree of conformance and method of implementation for each requirement in this NASA Technical Standard and identifies applicable in-house specifications used to comply with the requirement.
Other documents, such as contractor-specific M&P requirements documents and detailed requirements compliance matrices, can be used to form the basis of the Materials and Processes Selection, Control, and Implementation Plan, provided the content addresses the requirements.
- b. [MPR 10] The Materials and Processes Selection, Control, and Implementation Plan shall also describe the methods used to control compliance with these requirements by subcontractors and vendors.
Prime contractors may require subcontractors and vendors to develop a tailored plan to comply with NASA-STD-6016 or a tailored plan to comply with the prime contractor's plan. Alternatively, prime contractors may flow down a limited subset of (or even no) requirements, with the prime making up the difference between the subset and materials control plan. Whichever approach is selected, prime contractors are responsible for ensuring that hardware designed and fabricated by their subcontractors meet the materials control plan or NASA-STD-6016.
- c. [MPR 11] Upon approval by the procuring activity, the Materials and Processes Selection, Control, and Implementation Plan shall become the M&P implementation document used for verification.
The Materials and Processes Selection, Control, and Implementation Plan should be approved by the responsible design authority. Additional requirements on the Materials and Processes Selection, Control, and Implementation Plan content follow in sections 4.1.1.1 through 4.1.1.3.
4.1.1.1 Coordination, Approval, and Tracking
[MPR 12] The Materials and Processes Selection, Control, and Implementation Plan shall identify the method of coordinating, approving, and tracking all engineering drawings,
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
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engineering orders, and other documents that establish or modify materials and/or processes usage.
4.1.1.2 Approval Signature
[MPR 13] The Materials and Processes Selection, Control, and Implementation Plan shall include a requirement that all hardware design drawings and revisions for spaceflight hardware that provides mission-critical functions contain an M&P approval block, or equivalent, to ensure that the design has been reviewed by the responsible M&P authority and complies with that document.
4.1.1.3 Manufacturing Planning
[MPR 14] The Materials and Processes Selection, Control, and Implementation Plan shall identify how the responsible M&P organization participates in manufacturing and inspection/verification planning to ensure compliance with M&P requirements.
4.1.2 M&P Controls
- a. [MPR 15] All M&P for spaceflight hardware that provides mission-critical functions shall be defined by standards and specifications selected from government, industry, and company specifications and standards.
- b. [MPR 16] All M&P for spaceflight hardware that provides mission-critical functions shall be identified directly on the appropriate engineering drawing.
- c. [MPR 17] Company M&P specifications shall be identified by document number in the Materials and Processes Selection, Control, and Implementation Plan.
- d. [MPR 18] All M&P specifications used to produce spaceflight hardware that provides mission-critical functions shall be made available to the responsible NASA Program or Project Office and M&P organization.
- e. [MPR 19] Process specifications for spaceflight hardware that provides mission-critical functions shall define process steps at a level of detail that ensures a repeatable/controlled process that produces a consistent and reliable product.
- f. [MPR 20] Process qualification shall be conducted to demonstrate the repeatability of all processes for spaceflight hardware that provides mission-critical functions where the quality of the product cannot be directly verified by subsequent monitoring or measurement.
Note: The process requirements in section 4.2.4 of this NASA Technical Standard do not always define process steps at a level of detail that ensures a repeatable/controlled process that
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
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produces a consistent and reliable product, so it should not be assumed that they are suitable to be called out as process specifications on engineering drawings. They are intended as higher level documents that state minimum requirements and provide general directions for the design of hardware.
4.1.2.1 Standard and Specification Obsolescence
[MPR 21] A process shall be established for ensuring that updated, alternate, or new material or process standards or specifications from those identified in the Materials and Processes Selection, Control, and Implementation Plan meet or exceed the technical requirements identified in the original material or process standards or specifications.
During a long-term program, M&P standards and specifications identified in this document or in contractor materials control plans could become obsolete. Continued use of obsolete standards and specifications is acceptable for manufacturing series or new-design hardware. Although updated M&P standards or specifications usually meet or exceed earlier standards and specifications, their use can result in requirements creep so that new hardwire no longer meets the original design requirements.
4.1.3 Commercial Off-The-Shelf (COTS) Hardware
[MPR 22] A procedure shall be established to ensure that all vendor-designed, off-the-shelf, and vendor-furnished items are covered by the M&P requirements of this document, with the exception that M&P requirements for off-the-shelf hardware and other spaceflight hardware that do not provide mission-critical functions may be limited to those required to ensure safety of flight (for example, flammability, toxic offgassing) and vehicle compatibility (for example, vacuum outgassing).
4.1.4 M&P Control Panel
- a. [MPR 23] An M&P control panel shall be established by each contractor hardware provider (excluding subcontractors).
- b. [MPR 24] The M&P control panel’s scope and membership shall be described in the Materials and Processes Selection, Control, and Implementation Plan.
The M&P control panel plans, manages, and coordinates the selection, application, procurement, control, and standardization of M&P for the contract.
The panel also resolves and dispositions M&P problems.
The responsible NASA M&P organization is an active member of the panel and has the right of disapproval of panel decisions.
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
NASA-STD-6016B
4.1.5 M&P Usage Documentation
- a. [MPR 25] M&P usage shall be documented in an electronic, searchable parts list or separate electronic searchable Materials Identification and Usage List (MIUL) with the following exceptions:
- (1) Electrical, electronic, and electromechanical (EEE) parts other than wire, cable, and exposed surfaces of connectors.
- (2) Materials used in hermetically sealed electronic containers (maximum leak rate less than 1 x 10⁻⁴ cm³/sec).
- b. [MPR 26] The documentation of M&P usage shall cover the final design as delivered.
- c. [MPR 27] The documentation approach shall be defined in the Materials and Processes Selection, Control, and Implementation Plan.
Recommended MIUL content is described in Appendix D, Recommended Data Requirements Documents. Material codes and ratings for materials, standard and commercial parts, and components are available in the Materials and Processes Technical Information System (MAPTIS). When required, new material codes will be assigned by NASA's Marshall Space Flight Center (MSFC). In some cases, MAPTIS contains averages for ratings or test results for generic materials controlled by military or industry specifications; the material codes for the generic materials are used.
MAPTIS is accessible via the Internet at http://maptis.nasa.gov.
Note: Accessibility to MAPTIS is by registration only.
4.1.6 Material Usage Agreements (MUAs)
- a. [MPR 28] MUAs containing sufficient information to demonstrate that the application is acceptable shall be submitted by the responsible M&P organization for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
The use of M&P that do not comply with the requirements of this NASA Technical Standard may still be acceptable in the actual hardware applications.
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
NASA-STD-6016B
The MUA generation and approval system should be defined in the Materials and Processes Selection, Control, and Implementation Plan. A recommended MUA approach is described in Appendix D.
b. [MPR 29] MUAs shall not be used to change the M&P requirements for a nonconforming product.
When the nonconformance is a deviation from M&P requirements that is acceptable for future series hardware, an MUA may be generated to provide technical support for a change to the product baseline.
A typical MUA form is shown in Appendix B, Typical MUA Form.
4.1.6.1 Human-Rated Spacecraft
For human-rated spaceflight hardware, a tiered MUA system with three categories is recommended.
4.1.6.1.1 Category I MUAs
Category I MUAs are those that involve M&P usage that could affect the safety of the mission, crew, or vehicle or affect the mission success but have to be used for functional reasons.
Category I MUAs are delivered by the hardware developer and approved by the responsible NASA M&P organization and the NASA Program/Project Office.
4.1.6.1.2 Category II MUAs
Category II MUAs are those that involve M&P usage that fails a screening of M&P requirements and is not considered a hazard in its use application but for which no Category III rationale code exists. Category II MUAs are delivered by the hardware developer and approved by the responsible NASA M&P organization.
4.1.6.1.3 Category III MUAs
Contractors who want to use Category III rationale codes relevant to their hardware may do so through their Materials and Processes Selection, Control, and Implementation Plan. Category III MUAs are those that involve M&P that have not been shown to meet these requirements but have an appropriate rationale code listed in the Materials and Processes Selection, Control, and Implementation Plan. The rationale codes are approved as part of the overall Materials and Processes Selection, Control, and Implementation Plan approval. Category III rationale codes are evaluated and determined to be acceptable at the configuration/part level.
Approved Category III MUAs are reported in the MIUL system or electronic data system. NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
NASA-STD-6016B
Category III MUAs are approved by the hardware developer and responsible M&P organization through acceptance of the MIUL. No MUA form is submitted.
Note: The Category III MUA rationale codes in the previous release of this NASA Technical Standard have been retired, either because the acceptance rationale was deemed inadequate or because the application was made an exception to the requirement. Retired codes are listed in Appendix C, Retired Category III MUA Rationale Codes, for continuity purposes but should not be used for hardware designed to this NASA-STD-6016 release unless they are listed as approved rationale codes in the Materials and Processes Selection, Control, and Implementation Plan.
4.1.7 Materials Certification and Traceability
- a. [MPR 30] All parts or materials for spaceflight hardware that provides mission-critical functions shall be certified as to composition, properties, and requirements as identified by the procuring document.
- b. [MPR 31] With the exception of off-the-shelf parts, parts and materials used in critical applications, such as life-limited materials and/or safety- and fracture-critical parts, shall be traceable through all processing steps defined in the engineering drawing to the end-item application.
- c. [MPR 32] Distributors or other processors shall not heat treat, hot work, or cold work metal stock unless they take the responsibilities as the producer of the metal and produce a new certification.
Processing records should be retained for the life of the program. Processing records for program residual hardware should be delivered to the procuring authority as part of contract termination.
4.1.8 Material Design Values
In the design and analysis of aerospace hardware, the terms “material allowables,” “design allowables,” and “design values” are commonly used to address the design values used in structural analysis. The term “design values” is used throughout this document which encompasses both the material and design feature performance, whichever is used to support the structural certification.
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
NASA-STD-6016B
4.1.8.1 Requirements for Design Values
- a. [MPR 33] A, B, or S-basis statistical values for mechanical properties of materials shall be utilized for the design and analysis of hardware for all applications where structural analysis is required.
Statistical design values are needed for any hardware where structural analysis is required in order to demonstrate positive margins of safety for the design loads and environments in combination with the factor of safety requirements.
Each distinct form of a material should be assumed to have unique design values unless testing and statistical analysis shows that design values are combinable. For example, rolled bar may have different design values than the same alloy in plate, forging, spin forming, extrusion, or casting. Different layups affect the properties of composite structures. Manufacturing methods, like welding, brazing, swaging, forming, diffusion bonding, adhesive bonding, and co-curing of sandwich alter the properties of the original materials. Design features, such as joints, ply-drops, and tapered ramps affect the design values of composites.
Design values are also required for other mechanical properties, such as dynamic properties like fatigue and fracture. The basis for these properties is not necessarily statistical, but the sampling is expected to be representative of the material, product form, and state used in the design. Some applications require lower bound, and others require typical properties. The specific requirement can be found in the governing specifications for the design, such as NASA-STD-5019, Fracture Control Requirements for Spaceflight Hardware, or NASA-STD- 5012, Strength and Life Assessment Requirements for Liquid-Fueled Space Propulsion System Engines.
- b. [MPR 34] The sampling for other mechanical properties, such as dynamic properties like fatigue and fracture, and verification of design values shall be representative of the material, product form, and state used in the design.
The statistical basis for fatigue and fracture properties should be consistent with the governing specification. For example, NASA-STD-5019 allows for the use of typical fracture toughness and crack growth rate properties in the assessment of assumed defects; NASA-STD-5012 requires the use of bounding fatigue design curves for critical hardware in the primary load path. Fatigue data provided in MMPDS requires further analysis to derive a bounded design curve.
- c. [MPR 35] A, B, or S-basis statistical methods shall be defined by, and values for mechanical properties in their design environment taken from MMPDS, Metallic Materials Properties Development and Standardization, or SAE CMH-17, Composite Materials Handbook.
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
NASA-STD-6016B
S-basis statistical values apply to metallic structures only. Although SAE CMH-17 does use the term “S-basis,” it is used only for screening composite materials and such values may not be used in design.
Design values in CMH-17 Volume 2 may be used only if each production facility substantiates that its material and process controls produce repeatable and reliable results that support the published design value. "Equivalency" test methods such as those outlined in DOT/FAA/AR-03/19, Material Qualification and Equivalency for Polymer Matrix Composite Material Systems: Updated Procedure, are acceptable.
d. [MPR 36] For metallic materials, the alloy, heat treatment, product specification, product form, and thickness shall match the alloy, heat treatment, product specification, product form, and thickness in MMPDS.
Since the testing to develop design values is specific to alloy, heat treatment, specification and form, the statistical relationship is relevant only to that same combination. Thickness affects strength of metal because of metallurgical factors that influence strength, like heat transfer during heat treatment and variability of reduction during metal working.
SAE CMH-17 is composed of six volumes: SAE CMH-17-1G, Volume 1 – Polymer Matrix Composites Guidelines for Characterization of Structural Materials; SAE CMH-17-2G, Volume 2 – Polymer Matrix Composites Materials Properties; SAE CMH-17-3G, Volume 3 – Polymer Matrix Composites Materials Usage, Design, and Analysis; SAE CMH-17-4B, Volume 4 – Metal Matrix Composites; MIL-HDBK-17-5, Volume 5 – Ceramic Matrix Composites; and SAE CMH-17-6, Volume 6 – Structural Sandwich Composites.
Notes
- (1) Design values of structural materials listed in later versions of MMPDS or SAE CMH-17 than those specified in section 2 may be used provided the methodology used to develop the allowable mechanical properties is at least as conservative.
- (2) When released, SAE CMH-17-5 may be used in place of MIL-HDBK-17-5. SAE CMH-17-5 is scheduled for publication in 2017.
- (3) Published properties need to be appropriate for the design environment. For example, published properties at ambient temperature are not typically appropriate for applications in high-temperature environments.
- (4) Design Values calculated based on regression analysis according to SAE CMH-17 (Volume 1, section 8.3.7) are acceptable.
- (5) Caution is warranted for material properties that significantly exceed minimum specification values. Sensitivity to stress corrosion cracking, loss of ductility and
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
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fracture toughness, and degraded mechanical properties at cryogenic temperatures, may result in some alloys that are over-strengthened. For example, for quenched and tempered alloy steels, precipitation hardened steels, heat treatable aluminum etc., the durability and behavior in service environments may be adversely affected when they are strengthened significantly beyond their minimum strength requirements.
- (6) Section 4.2.2 of this NASA Technical Standard contains requirements for test verification of the adequacy of the heat treatment process when metallic materials are user heat treated.
- (7) For composite structures, “pristine” A and B-basis design values may not be appropriate as they can be compromised by manufacturing defects, mishandling, impacts, etc. Such damage is commonly in the form of subsurface delaminations that cannot be seen by visual inspection or detected by a practical NDE program. Degraded design values that take into account damage tolerance may be substantially lower than pristine design values, and may be required in accordance with NASA-STD-5019, Fracture Control Requirements for Spaceflight Hardware.
- e. [MPR 37] When statistical design values for new or existing structural materials are not available, they shall be determined by methods described in MMPDS or SAE CMH-17 and a report documenting the derivation of the new design values be made available to NASA for review.
Design values for polymeric materials other than composites are covered by this requirement but are not addressed by MMPDS or SAE CMH-17. The methods described in SAE CMH-17 are appropriate for such materials.
It is recognized that the development of statistical design values may, at times, be impractical for materials in extreme environments given project resource limitations. In such cases, the contractor should develop a tailored approach to adequately substantiate the design values for the environment and submit the approach and design values for approval via an MUA.
- f. [MPR 38] The implementation of an approach for generating statistical design values that deviates from the sampling methodology and statistical methods in MMPDS or SAE CMH-17 and the use of design values that deviate from those published in MMPDS or SAE CMH-17 shall be approved with an MUA.
At a minimum, the following should be should be addressed in the MUA documenting the rationale for use of the alternative approach for generating statistical design values that deviate from the guidance in MMPDS or SAE CMH-17.
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
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- (1) Description of the statistical approach.
- (2) Description of the number of test specimens, number of lots, heats, and/or production units, e.g., weld panels, castings, parts.
- (3) Description of the range of relevant process parameters.
- (4) Verification that the test specimens are representative of the product specification and product form used in the design (for metallic materials, the heat treatment and thickness also need to be verified as representative).
The following should be addressed in the MUA documenting the rationale for use of the alternative design values:
- (1) How the design values have been derived.
- (2) How future material lots will be verified for performance.
- (3) Justification for use of the alternate statistical methods or the use of engineering reduction factors.
For new or modified production methods, consistency with the original qualification testing and the associated design values should be demonstrated at an appropriate structural scale.
- g. [MPR 39] All contractor-developed mechanical and physical property data shall be made available to the responsible NASA M&P organization.
4.1.8.2 Design Value Implementation in Design
- a. [MPR 40] Material "B" design values shall not be used except in redundant structure in which the failure of a component would result in a safe redistribution of applied loads to other load-carrying members.
Material “B” or “B-basis” design values are specified to assure reliability for redundant structures, which are typically components or structural elements with a redundant load path. Material “A” or “A-basis” design values may be used in lieu of Material “B” or “B-basis” because they are derived using a more conservative statistical method.
Note: For nonmetallic structures, this requirement applies only to pristine material “B” design values. For fracture-critical nonmetallic structures, B-basis design values should be used in accordance with the methods outlined in NASA-STD-5019. B-basis design values developed for intentionally damaged structure as part of damage tolerance assessment may be acceptable for non-redundant structure. As strength and life verification of composites requires empirical
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.
NASA-STD-6016B
testing, it may become necessary to first develop design values representing the intrinsic material constitutive properties, and then separately establish design values for discrete design features which cannot be adequately correlated via traditional stress analysis. Examples may include complex ply-drop scenarios, discontinuities, composite/metallic interfaces, sandwich ramps, or unique bonded/bolted joints. In such cases, strictly using “material” design values rather than establishing design values specific to the design feature may result in an inadequately designed structure.
[Composite damage tolerance is outside the scope of this NASA Technical Standard; NASA-STD-5019, Fracture Control Requirements for Spaceflight Hardware, contains requirements on this subject.]
- b. [MPR 41] Minimum property acceptance values in material specifications (specification minimums) not explicitly published as "S" design values in MMPDS shall require an approved MUA for use as design values.
MMPDS requires three distinct lots of metal be tested and the data statistically analyzed and tested before the "S" design values are published in the handbook.
To minimize MUA activity, a process or set of standardized criteria can be defined in the Materials and Process Control Plan to allow the use of specification minimums for design without MUAs. Approaches could include extra lot testing, proof testing, substantiating the “S” basis over time, high margin applications, or the use of substantiated engineering reduction factors.
4.1.8.3 Structural Fastener Design Values
[MPR 42] Structural fastener design values shall be defined by minimum load test requirements in the applicable part and/or procurement specification (government, aerospace industry consensus, company-specific, or custom specification).
MMPDS design values are not transferrable to fasteners, because raw material used to make fasteners is reprocessed using various metallurgical practices such as hot heading, thread rolling, and heat treating. These processes change the strength of the metal from the original bar stock. NASA has chosen to adopt lot tested design strength defined in the specific fastener part and procurement specifications as the design value instead of the certifications of the original bar stock.
Other structural fastener requirements are identified in section 4.2.6.6.
NOTE: Per section 4.1.6: The use of M&P that do not comply with the requirements of this NASA Technical Standard may be acceptable in the actual hardware applications. MUAs are required for all M&P that are technically acceptable but do not meet the requirements of this NASA Technical Standard, as implemented by the approved Materials and Processes Selection, Control, and Implementation Plan.