This document recapitulates some of the concepts in the qualification process and helps in drawing up the Qualification File (QF) for a system and its segments (flight and ground segments, including items of equipment or instruments). It also has an instructive aspect, running over some of the main principles for use for all those involved in the qualification process. Finally, it provides a standard template to help structure the presentation of a QF for internal use or for a customer.
For more details, please refer to the CNES Standards Reference (RNC) document "RNC-CNES-Q-HB-10-501 Guide to compiling a qualification status file for a system and its segments".
Qualification is a particular process in the more general verification process which serves to demonstrate that the design of a system and its segments (elements in the product tree), including margins, meets all the applicable requirements. This definition can naturally apply to items of equipment or instruments.
The margins must cover the uncertainties regarding the design itself, the lack of complete knowledge concerning the environmental constraints for the entire life cycle (e.g. AIT, storage, launch, mission) and also the dispersal of manufacturing of the element(s) to be actually used by the customer during the mission.
Reminder: the design of a system or a segment is the set of information that is necessary and sufficient to describe all its characteristics (information generally brought together in the Production File (Definition File (DF) + Manufacturing File (MF) + Control File (CF) and the Definition Justification File (DJF)).
B. Qualification Concepts and Qualification File
The verification process consists in ultimately ensuring that the requirements made applicable by the Customer are satisfied, i.e.
1) The Specification of Requirement (STB), which group requirements of differing natures together:
- functional requirements associated with the mission (performance, characteristics, modes, mission-related operations, etc.),
- environmental requirements relating to life cycle constraints: ground (transportation, storage), launch phase, life in orbit (0g, vacuum, radiation, solar radiation, micrometeorites, etc.). Please refer to the document "RNC-ECSS-E-ST-10-03 Testing".
- interface requirements: electrical, mechanical, thermal, software, communication protocol, etc. relative to the interfaces with the other products.
- "operational" requirements (in the logistical sense): availability, maintainability, reliability, safety, the human factor, ergonomics, etc.
- output assurance requirements (in other words the mandatory solutions) relating to the justification/qualification of the definition, product acceptance (methods and/or level of verification and/or mandatory models).
2) RNC requirements applicable to the project (management, quality assurance and engineering):
- technical requirements with a direct impact on the design of the product, from the M, Q and E branches of the RNC (ECSS, etc.).
Electrical design requirements, mandatory torque margin, etc.
Component derating requirements (RNC-ECSS-Q-ST-30-11)
Design requirements in terms of Dependability (RNC-ECSS-Q-ST-Q-30)
- technical requirements with a direct impact on the design, linked to the backing up and security of the Information Systems, the Space Operations Act (space debris, etc.), planetary protection, etc.
To demonstrate that the design, including the margins, satisfies all the requirements applicable to it, a tailored verification process must be set up for each of these "families" of requirements.
It is assumed that the STB requirements for the elements in the technical tree have been applied, i.e. that on the basis of the design activities, the links between requirements have been defined (sometimes referred to as "requirement traceability"). For this, please refer to section M-11 (Requirement management plan for reviewing conformance).
The links between all the project's requirements and the verification elements and verification results from the project are then established. All the QFs coming from suppliers must also be available.
Thus, for each of the project's requirements, it is possible to associate the results of verifications performed as part of the project and those performed at the lower level.
For items of equipment or instruments for which qualification must be delivered, a Qualification Plan (QP) is first drawn up. The centre point of this QP is the requirement verification matrix.
Since this matrix is not enough in itself to sufficiently describe the qualification sequence for the element, the plan sets out the sequence of tests on the models, their succession, the qualifications to be obtained at a lower level in the tree, any tests to be performed at a higher level, the status of configuration applicable to the element, etc.
It is set at the Critical Design Review (CDR) for the product and the matrix is filled in, except of course for the verification results (apart from previously checked requirements at the lower level in the tree).
Drawing up the QF is a continuous process consisting in checking on the requirements during development in accordance with the QP. This QF is to be provided to the customer at the next level up in the product tree so that it may also compile the QF for the product under its responsibility.
The simplified flow chart below shows the interaction between STB, QP and QF for level n in the product tree.
C. Typical content
Example: content elements for an item of equipment or flight instrument
The reference of the STB, its DF, DJF, Qualification Plan (QP)
The description of the qualification sequence for performance, interface and environmental requirements: at which level in the tree, on which model(s), by what method and what level of constraint (QP extract)
The category linked to the inheritance (categories A, B, C or D) - please refer to "RNC-ECSS-E-ST-10-02" table 5.1 page 20
Requirement verification matrix (initial QF) and the results (intermediate and final QFs) - please refer to EF-5
Identification of requirements contributing to the qualification of a product from a lower level (or levels) and the results
Identification of the requirements remaining to be verified at a higher level (or levels)
Anomalies encountered during qualification tests and their final status (including concessions)
Changes made to the definition since qualification and their consequence on its validity
Changes made to the QP (set at the CDR) and their consequences on the validity of the qualification
The validation status of component lists, materials, mechanical parts and processes, software modules
The status of the file relating to "space debris" requirements