CEN/CLC/TR 17602-80-01:2021

SLOVENSKI STANDARD
01-december-2021
Zagotavljanje kakovosti proizvodov v vesoljski tehniki - Ponovna uporaba
obstoječe programske opreme
Space product assurance - Reuse of existing software
Raumfahrt-Produktsicherung - Wiederverwendung vorhandener Software
Assurance produit des projets spatiaux - Réutilisation de logiciels existants
Ta slovenski standard je istoveten z: CEN/CLC/TR 17602-80-01:2021
ICS:
03.120.99 Drugi standardi v zvezi s Other standards related to
kakovostjo quality
35.080 Programska oprema Software
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/CLC/TR 17602-80-
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
October 2021
ICS 49.140; 35.240.99
English version
Space product assurance - Reuse of existing software
Assurance produit des projets spatiaux - Réutilisation Raumfahrtproduktsicherung - Wiederverwendung
de logiciels existierender Software

This Technical Report was approved by CEN on 13 September 2021. It has been drawn up by the Technical Committee
CEN/CLC/JTC 5.
CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

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© 2021 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. CEN/CLC/TR 17602-80-01:2021 E
reserved worldwide for CEN national Members and for
CENELEC Members.
Table of contents
European Foreword . 4
Introduction . 5
1 Scope . 6
2 References . 7
3 Terms, definitions and abbreviated terms . 9
3.1 Terms from other documents . 9
3.2 Terms specific to the present document . 9
3.3 Abbreviated terms. 10
4 Overview of the handbook . 11
4.1 Introduction . 11
4.2 Relation to other ECSS Standards . 12
4.2.1 General . 12
4.2.2 Software engineering . 12
4.2.3 Software product assurance . 13
4.2.4 Project management . 13
5 Software reuse approach . 14
5.1 Introduction . 14
5.2 Requirements phase . 16
5.2.1 Overview . 16
5.2.2 Requirements identification . 16
5.2.3 Gap analysis . 17
5.2.4 Derived requirements identification . 18
5.3 Assessment phase . 18
5.3.1 Overview . 18
5.3.2 Assessment . 18
5.3.3 Selection . 20
5.4 Integration phase . 21
5.4.1 Overview . 21
5.4.2 Incoming inspections . 21
5.4.3 Configuration management . 22
5.4.4 Adaptation of the existing software . 22
5.5 Qualification phase . 24
6 Tool qualification . 26
6.1 Introduction . 26
6.2 Tool qualification level . 26
6.3 Tool qualification . 28
7 Techniques to support qualification when reusing existing software . 32
7.1 Introduction . 32
7.2 Verification techniques . 33
7.2.1 Black box techniques . 33
7.2.2 White box techniques . 34
7.3 SW design techniques . 39
7.4 Hardware architecture techniques . 42
7.5 Reverse engineering . 43
7.6 Product service history . 44
7.7 Development process examination . 46
Annex A Content of Software Reuse File (SRF) . 47
Annex B Content of the Product Service History file . 52
Annex C Risk management considerations . 56
C.1 Introduction . 56
C.2 Risk scenarios and mitigation actions . 56

Figures
Figure 4-1: Organization of the handbook . 12
Figure 5-1: Specific reuse activities within project . 15
Figure 6-1: Tool qualification levels . 27

Tables
Table 6-1: Example of combination of classes of methods . 29
Table 7-1: Example of combination of classes of methods . 38

Table B-1 : Anomaly rate estimation . 54
Table B-2 : Anomaly rate versus time . 55

European Foreword
This document (CEN/CLC/TR 17602-80-01:2021) has been prepared by Technical Committee
CEN/CLC/JTC 5 “Space”, the secretariat of which is held by DIN.
It is highlighted that this technical report does not contain any requirement but only collection of data
or descriptions and guidelines about how to organize and perform the work in support of EN 16602-
80.
This Technical report (CEN/CLC/TR 17602-80-01:2021) originates from ECSS-Q-HB-80-01A .
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such
patent rights.
This document has been prepared under a mandate given to CEN by the European Commission and
the European Free Trade Association.
This document has been developed to cover specifically space systems and has therefore precedence
over any TR covering the same scope but with a wider domain of applicability (e.g.: aerospace).
Introduction
This handbook provides guidance on the approach that can be taken when defining the
implementation of activities for the reuse of existing software within a space project.
Existing software is defined in ECSS-Q-ST-80 as follows:
• Any software from previous developments that is used for the project development as is or
with adaptation. It also includes software supplied by the customer for use in the project
development.
• Any software including any software developed outside the contract to which ECSS software
standards are applicable.
• Any software including products such as freeware and open source software products.
In the development of software systems or products, different types of existing software artefacts can
be reused, such as:
• Requirements, when reused early in the software product requirements definition.
• Components, when reused early in the software product architecture definition.
• Modules, when reused at detailed design level.
• Libraries and source code, when reused at coding level.
• Documents, plans, tests, and data are other software items that can be reused.
This handbook adopts a broader interpretation of the term ‘existing software’, and assumes that it can
comprise the ‘reuse’ of tools for the development of any space software product.
Furthermore, the effective reuse existing software is based on the possibility to fully understand it
with respect to properties such as functionality, quality, performance, dependability or safety and to
find and adopt it to the development faster than it otherwise can be constructed.
However, whatever is the level of reuse, the quality of the reused existing software is of utmost
importance, as low quality can easily lead to system failure and thus loss of mission even for the
lowest reuse level. Consequently, significant analyses should be carried out when using existing
software. Furthermore, policies that favour reuse of existing software should be adopted with an
understanding of the complex impacts of using the already available software.
Scope
This handbook provides recommendations, methods and procedures that can be used for the selection
and reuse of existing software in space software systems.
This handbook is applicable to all types of software of a space system, including the space segment,
the launch service segment and the ground segment software (including EGSEs) whenever existing
software is intended to be reused within them.
This handbook covers the following topics:
• Software reuse approach including guidelines to build the Software Reuse File
• Techniques to support completion of existing software qualification to allow its reuse in a
particular project
• Tool qualification
• Risk management aspects of reusing existing software
Existing software can be of any type: Purchased (or COTS), Legacy-Software, open-source software,
customer-furnished items (CFI's), etc.
Special emphasis is put on guidance for the reuse of COTS
software often available as-is and for which no code and
documentation are often available.
Legal and contractual aspects of reuse are in principle out of scope; however guidelines to help in
determine the reusability of existing software from a contractual point of view is provided in
[ESA/REG/002].
Any organization with the business objective of systematic reuse may need to implement the
organizational reuse processes presented in [ISO12207]. These processes will support the identification
of reusable software products and components within selected reuse domains, their classification,
storage and systematic reuse within the projects of that organization, etc. But these processes are out
of scope of this handbook as the handbook is centred on the specific project activities to reuse an
existing software product, not part of those organizational reuse processes more oriented to ‘design
for reuse’ processes.
In addition, this handbook provides guidelines to be used for the selection and analysis of tools for the
development, verification and validation of the operational software.
CEN
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