ECSS-Q-HB-80-01A – Reuse of existing software (5 December 2011)


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.

NOTE: 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 []. 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 centered 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.



This handbook supports following ECSS Standard: ECSS-Q-ST-80C – Software product assurance (6 March 2008).