SEL Reuse Study

Approach

The study team began by conducting numerous in-depth interviews with personnel involved in the development and use of GSS. At the same time, data from the SEL database were analyzed to determine the costs of developing and using GSS. All of this data was then used to create a detailed process model of the GSS application deployment process, an analysis of the cost benefits of GSS, and a list of issues and recommendations for the future use of GSS.

A second phase of the study concentrates on alternatives to GSS and their relative merits. Again, we have interviewed personnel of various kinds, especially mission team personnel who are making decisions about how to produce the attitude software required by their missions. We will use this information to attempt to capture the decision-making process and the important criteria used.

The Reuse Study has also joined forces with the SEL COTS study, which is focusing on the use of COTS in the FDD. Many of the goals of these two studies are similar, so we are combining our data collection efforts, particularly in conducting interviews.

Project Status

Active, but transitioning - the second phase is wrapping up, and we are looking towards new tasks, particularly baselining some of the new organizations resulting from the Goddard reorg in late 1997.

Results

Analysis of the cost data associated with GSS indicated that configuring attitude software with GSS costs roughly 10% of what it used to cost when such systems were built based on Ada or FORTRAN libraries. Also, we found that if the FDD continues to deploy GSS-based applications for 10% of the cost of the preceding era, the FDD will recoup the entire cost of building GSS by the fourth GSS-supported mission.

We have also made a set of recommendations for effective use of GSS in the future. These include

• an electronic or database format for storing, manipulating, and reusing mission attitude requirements
• automatic generation of configuration inputs (from the above electronic or database format)
• tools to facilitate the learning of GSS concepts and to simplify the configuration process from the user's point of view