ECSS-E-40A – Software (13 April 1999)

This standard has been cancelled and replaced by ECSS-E-40 Part 1B  (28 November 2003) and ECSS-E-40 Part 2B (28 November 2003).


This software engineering standard concerns the “Product software”, i.e. software that is part of a space system product tree and developed as part of a space project.

This standard is applicable to all the elements of a space system, including the space segment, the launch service segment and the ground segment.

This standard covers all aspects of space software engineering including requirements definition, design, production, verification and validation, and transfer, operations and maintenance.

It defines the scope of the space software engineering process and its interfaces with management and product assurance, which are addressed in the Management (-M) and Product assurance (-Q) branches of the ECSS System, and explains how they apply in the software engineering process.

This standard reflects the specific methods used in space system developments, and the requirements for the software engineering process in this context. Together with the requirements found in the other branches of the ECSS Standards, this standard provides a coherent and complete framework for software engineering in a space project.

This standard is intended to help customers in formulating their requirements and suppliers in preparing their response and implementing the work.

This standard is not intended to replace textbook material on computer science or technology, and such material has been avoided in this standard. The readers and users of this standard are assumed to possess general knowledge of computer science.

The scope of this standard is the software developed as part of a space project, i.e. “Space system product software”. It is not intended to cover software developments out of scope with the ECSS System of standards.An example is the development of commercial software packages, where software is developed for a (large) volume market and not just for a single customer, and the main requirement analysis consists of market analysis, combined with a marketing strategy.

Other classes of software products not covered are:management information systems (e.g. finance, planning), technical information systems (e.g. CAD/CAM, analysis packages) and supporting software products for documentation systems, database systems, spread-sheets. These usually result from the procurement or adaptation of existing commercial products, and not part of the space system development.

Such software products will, however, often be part of a supporting infrastructure
for space systems.