A Framework for the Development of Multi-Mission Software

A model for producing more maintainable multi-mission software is presented in the context of mkarf, the program that produces ancillary response files (ARFs) for the Chandra X-Ray telescope. The basic strategy employs the methods of object-oriented programming, and consists of encapsulating the mission-dependent pieces into subclasses that derive from more mission-independent abstract base classes. In particular, mkarf interacts with mission-specific calibration data via a library called ardlib, which provides a mission-independent class interface to objects that represent effective areas, quantum efficiencies, and so on. For this reason, much of the discussion centers upon the design of ardlib itself.