Verification (spaceflight)

Verification in the field of space systems engineering covers two verification processes: Qualification and Acceptance

Overview

In the field of spaceflight verification standards are developed by NASA and the ECSS, and to specify requirements for the verification of a space system product, such as:^[1]

• the fundamental concepts of the verification process,
• the criteria for defining the verification strategy and
• the rules for the implementation of the verification programme.

Verification is one main reason that costs for space systems are high. All data are to be documented and to stay accessible for potential, later failure analyses. In previous times that approach was executed down to piece-parts level (resistors, switches etc.) whereas nowadays it is tried to reduce cost by usage of "CAM (Commercial, Avionics, Military) equipment" for non-safety relevant units.

Qualification and Acceptance

Qualification is the formal proof that the design meets all requirements of the specification and the parameters agreed in the Interface Control Documents (ICD) including tolerances due to manufacturing imperfections, wear-out within specified life-time, faults etc. The end of the qualification process is the approval signature of the customer on the Certificate of Qualification (COQ) agreeing that all his requirements are met.

Acceptance is the formal proof that the product identified by its serial number meets all requirements of the specification and is free of workmanship and material failures. Acceptance is based on the preceding qualification by reference to the used design / manufacturing documentation. The end of the acceptance process is the approval signature of the customer on the Certificate of Acceptance (COA) agreeing that all his requirements are met by the product to be delivered.

Qualification verification methods are

• Review of design using configuration controlled drawings (for software code review)
• Analysis
• Test (functions under specified environment, mass, dimensions etc.)
• Inspection (especially for Human Factors Engineering requirements with astronauts for manned spacecraft).

Each software element will be tested alone and as part of the overall system configuration until considered as qualified.

Acceptance verification methods are

• Test
• Inspection by Quality Assurance engineers.

See also

• Spacecraft
• System engineering

References

Further reading

• ECSS-E-ST-10-02: Verification (European Space Standard)