In the Space and Defence markets, there is a clear trend towards software development contracts based on detailed requirements, fixed price, and fixed schedule. This trend implies that the contractor bears an increasing portion of the risk involved in balancing requirements, risk, and schedule.
The process improvement involves introduction of a well-defined program of development process measurement, definition of an estimation model that integrates measurements from earlier projects in the estimation process, and implementation of an organisational memory that allows this loop to be closed.
The result of the experiment is determined quantitatively in the regularly recurring assessments of the software development process. Also, the result of the experiment is determined more subjectively through the quality of the estimates actually produced in the baseline project as well as through a demonstration that the measurement program involved is operationally feasible.
The experiment is performed on the ERA project that delivers part of the on-board software for the European Robotics Arm as a subcontractor to a prime contractor that in turn is under contract with the European Space Agency. The project has incremental delivery stages, which allow the experiment to close the loop from measurement of an early stage to estimation of a later stage. Other projects with similar characteristics are being considered as supplementary baseline projects.
EXPECTED IMPACT AND EXPERIENCE
CRI hopes to demonstrate that useful estimation procedures can be based on an approach which is reasonably formalised, yet still based on a bottom-up approach. This has been identified as the estimation approach that is most likely to be useful in the long run in a contractor environment where it is difficult to establish historical data based on large numbers of similar projects.
The CRI Space Division is actively pursuing process improvements that will allow the division to qualify at level 2 of the SEI Capability Maturity Model. A successful outcome of ESTEX will help to overcome a major roadblock towards that goal.