Quality versus Complexity
Watts, Nigel; Watts, Nigel
ESA/ESTEC

The European Space Industry has well established standards such as those produced under the European Cooperation for Space Standardization (ECSS) written with the intent to reduce cost and improve both quality and communication during the preparation and execution of programmes.

Many Standards under the ECSS have been produced and applied to European Space Programmes at considerable effort and with some success. Nevertheless they are not without shortcomings.

The Galileo Experience in the definition of and compliance to project requirements and standards has been mixed.

GIOVE A has been an efficient high risk project to which the ECSS Standards were at best guidelines and in reality not often followed and yet the GIOVE A Satellite has largely fulfilled its main mission objectives, following a design to (low) cost approach.

GIOVE B has been a difficult project to complete at substantially higher cost, full applicability of the ECSS and a more complex industrial organisation and has followed a design to (meet) requirements approach.

IOV (The Galileo In Orbit Validation phase) has taken things to another level in terms of the number of interfaces, involvement of many external (non ESA) bodies in definition of requirements including security, planning and funding of the programme. IOV has an extremely large and complex ground segment. Furthermore the ECSS standards have been found wanting in a number of areas particularly in the Ground Segment and for the development of Safety Critical and Certifiable Software.

The precursor to Galileo, EGNOS, has also experienced some of these problems and certification has not yet been achieved for its use in safety of life applications.

This paper will examine the way ESA space project requirements are defined and applied with tailoring at the various contractual levels, using some examples from Galileo.

It will seek to demonstrate some alternatives in the definition of requirements and the application of standards according to the complexity of the product and services to which they apply. The goal should be to achieve relevant mission requirements more effectively without stifling innovation and within a defined cost envelope.