Extending the Product Family Approach to SupportSafe

Upcoming spacecraft will reuse software components to the extent that some systems will form product families of similar or identical units (e.g., a eet of spaceborne telescopes). Missions such as these must be demonstrably safe, but the consequences of broad reuse are hard to evaluate from a software safety perspective. This paper reports experience specifying an interferometer (telescope) subsystem as a product family and supplementing the speci cation with results from a failure analysis. Extensions to the product family approach, with lessons learned, are discussed in three areas: (1) integration of safety analysis with the product family approach; (2) modeling decisions that have safety implications (e.g., how to handle near-commonalities, establishing a hierarchy of variabilities, and specifying dependencies among options); and (3) use of the product family requirements for design evaluation of reusable components as well as a speci c product.