AEAIP knowledge · Glossary
Engineering assurance glossary
In short
Plain-language definitions of the verification, review, configuration and quality terms used across this site. Where frameworks use a term differently, the definition says so. Each term links to the page that explains it in depth.
Requirements & evidence
- Requirement
- A statement of what a system must do or be, written so that it can be verified. Good requirements are necessary, unambiguous, feasible and traceable to a need.Read more about Requirement
- Derived requirement
- A requirement created by the design team to implement a higher-level requirement, for example a subsystem power limit derived from a system power budget. It traces to its parent and carries a rationale.Read more about Derived requirement
- Evidence
- A record that supports a verification conclusion: a test report, analysis, inspection record, review record or telemetry set. Evidence is meaningful only together with the configuration and conditions it was produced under.Read more about Evidence
- Traceability
- The ability to follow a requirement up to the need it serves and down to the design, verification and evidence that satisfy it, in both directions.Read more about Traceability
- Verification matrix
- A table listing each requirement with its verification method, level, planned event, evidence and closure status. Often called a verification cross-reference matrix (VCRM) or verification control document.Read more about Verification matrix
- Evidence validity
- Whether a piece of evidence still applies to the requirement baseline and configuration currently under review. In the AEAIP model, evidence can be current, at risk, require reverification or be superseded.Read more about Evidence validity
- Engineering Evidence Graph™
- GAMYAA's model (in architecture) for connecting needs, requirements, design, configuration, verification, evidence, issues and approvals as typed nodes and relationships.Read more about Engineering Evidence Graph™
Verification
- Verification
- Confirmation, through objective evidence, that a product meets its specified requirements. It answers: did we build the product right?Read more about Verification
- Validation
- Confirmation that the product fulfils its intended use and stakeholder needs in its intended environment. It answers: did we build the right product?Read more about Validation
- Qualification
- Verification that a design meets its requirements with margin, usually by testing a dedicated unit at levels beyond the expected environment. Done once for a design.Read more about Qualification
- Acceptance
- Verification that each production or flight unit was built correctly and is free of workmanship defects, usually at expected environment levels. Done for every unit.Read more about Acceptance
- Protoflight
- An approach in which the flight unit itself is tested to levels between acceptance and qualification, used when no separate qualification unit is built. It accepts more risk to the flight hardware.Read more about Protoflight
- Certification
- Formal recognition by an authorised body that a product, design or organisation meets a defined set of requirements. Software tools can help prepare certification evidence; they do not certify.Read more about Certification
- Test article pedigree
- The documented history and configuration of the unit that was tested, and how it differs from the flight configuration. It decides whether a test result can be used as evidence for flight.Read more about Test article pedigree
- TVAC
- Thermal vacuum testing: operating hardware in vacuum across hot and cold temperature extremes to verify thermal design and functional performance in a space-like environment.Read more about TVAC
Model-based engineering
- MBSE
- Model-based systems engineering: using a connected system model, rather than separate documents, as the primary record of requirements, architecture, behaviour and verification.Read more about MBSE
- MIL (model-in-the-loop)
- Testing a control or software design model against a simulated plant before code is produced.Read more about MIL (model-in-the-loop)
- SIL (software-in-the-loop)
- Testing compiled software on a host computer against simulated hardware and environment.Read more about SIL (software-in-the-loop)
- PIL (processor-in-the-loop)
- Testing software on the target or a representative processor with simulated surroundings.Read more about PIL (processor-in-the-loop)
- HIL (hardware-in-the-loop)
- Testing real hardware, such as a flight computer, connected to simulated sensors, actuators and dynamics, so closed-loop behaviour can be verified on the bench.Read more about HIL (hardware-in-the-loop)
- Digital twin
- A model kept in step with a specific physical system using its data. In AEAIP, digital twins are treated as sources of engineering evidence.Read more about Digital twin
Issues & dispositions
- NCR
- Nonconformance report: the record raised when a product or process does not meet a requirement. It is investigated and dispositioned, for example rework, repair, use-as-is or scrap.Read more about NCR
- MRB
- Material Review Board: the authorised group that decides the disposition of nonconforming items.Read more about MRB
- Anomaly
- An unexpected behaviour or result during test or operation that must be investigated, explained and resolved or accepted.Read more about Anomaly
- Deviation
- Approved permission to depart from a requirement, usually granted before the work is done and limited in scope. Exact definitions vary by framework.
- Waiver
- Approved acceptance of an item or condition that does not meet a requirement, usually after the fact, with its risk accepted by the responsible authority. Some frameworks, including NASA's, distinguish deviation and waiver by when the requirement entered configuration control.
- Corrective action
- Action taken to remove the cause of a nonconformance or anomaly and prevent recurrence, followed by verification that it worked.
Configuration
- Configuration baseline
- An approved, controlled description of a product at a point in time, such as requirements, design or as-built, that can only change through formal change control.Read more about Configuration baseline
- Configuration item
- Hardware, software or documentation that is placed under configuration management and identified by part number, revision or version.Read more about Configuration item
- SBOM
- Software bill of materials: a list of the components, versions and suppliers that make up a software build.Read more about SBOM
Engineering reviews
- MCR — Mission Concept Review
- Confirms the mission need and that a feasible concept exists. Review sets and criteria are defined by each programme.Read more about MCR
- SRR — System Requirements Review
- Confirms the system requirements are a sound, verifiable baseline. Review sets and criteria are defined by each programme.Read more about SRR
- SDR — System Definition Review
- Confirms the architecture and requirement allocation meet the system requirements. Review sets and criteria are defined by each programme.Read more about SDR
- PDR — Preliminary Design Review
- Confirms the preliminary design meets requirements with acceptable risk, before detailed design. Review sets and criteria are defined by each programme.Read more about PDR
- CDR — Critical Design Review
- Confirms the detailed design is complete and ready to build and verify. Review sets and criteria are defined by each programme.Read more about CDR
- SIR — System Integration Review
- Confirms items, facilities and procedures are ready for integration. Review sets and criteria are defined by each programme.Read more about SIR
- TRR — Test Readiness Review
- Confirms a formal test is ready to start and will produce valid evidence. Review sets and criteria are defined by each programme.Read more about TRR
- SAR — System Acceptance Review
- Confirms the system is built, verified and ready for acceptance. Review sets and criteria are defined by each programme.Read more about SAR
- ORR — Operational Readiness Review
- Confirms systems, procedures and people are ready to operate. Review sets and criteria are defined by each programme.Read more about ORR
- FRR — Flight Readiness Review
- Determines whether the flight system is ready for a safe and successful flight. Review sets and criteria are defined by each programme.Read more about FRR
- MRR — Mission Readiness Review
- In GAMYAA's illustrative model, the final integrated readiness review across flight, ground, launch and operations. Review sets and criteria are defined by each programme.Read more about MRR
Quality & assurance
- FAI
- First Article Inspection: a complete, documented verification that the first production article meets every drawing and specification requirement.Read more about FAI
- AS9102
- The aerospace standard (SAE / IAQG) that defines First Article Inspection requirements and the structure of the First Article Inspection Report.Read more about AS9102
- Mission assurance
- The disciplined application of engineering, quality, safety, reliability and risk practices across the life cycle to raise confidence that a mission will succeed.Read more about Mission assurance
- Product assurance
- In ECSS usage, the discipline that covers quality assurance, dependability, safety, EEE components, materials and processes, and software product assurance for space products.Read more about Product assurance
References / Engineering Sources
Explanations on this page are original GAMYAA paraphrase. Standards are referenced, not reproduced; paid standards link to their publisher. Referencing a framework does not imply compliance with it.
- 01NASA Systems Engineering Handbook, NASA/SP-2016-6105 Rev 2 (opens in a new tab)
NASA
Life-cycle phases, technical reviews and the systems-engineering process model.
- 02ISO/IEC/IEEE 15288:2023, Systems and software engineering — System life cycle processes (opens in a new tab)
ISO / IEC / IEEE
Life-cycle process descriptions, including verification and validation processes.
- 03SAE EIA-649C, Configuration Management Standard (opens in a new tab)
SAE International
Configuration management functions and principles.
- 04ECSS-E-ST-10-02C Rev.1, Space engineering — Verification (opens in a new tab)
European Cooperation for Space Standardization
Verification methods (test, analysis, review-of-design, inspection), levels and stages.
- 05AS9102C, Aerospace Series — First Article Inspection Requirements (opens in a new tab)
SAE International / IAQG
First Article Inspection requirements and FAI Report structure.
- 06SEBoK — System Verification (opens in a new tab)
Systems Engineering Body of Knowledge (INCOSE, IEEE SMC, SERC)
Open reference on verification concepts and methods.
- Published by
- Gamyaa AeroSystems — Engineering Assurance Research
- Last reviewed
- Status
- Educational reference
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