SEQ-REVIEW: A tool for reviewing and checking spacecraft sequences

A key component of JPL's strategy to make space missions faster, better and cheaper is the Advanced Multi-Mission Operations System (AMMOS), a ground software intensive system currently in use and in further development. AMMOS intends to eliminate the cost of re-engineering a ground system for each new JPL mission. This paper discusses SEQ-REVIEW, a component of AMMOS that was designed to facilitate and automate the task of reviewing and checking spacecraft sequences. SEQ-REVIEW is a smart browser for inspecting files created by other sequence generation tools in the AMMOS system. It can parse sequence-related files according to a computer-readable version of a 'Software Interface Specification' (SIS), which is a standard document for defining file formats. It lets users display one or several linked files and check simple constraints using a Basic-like 'Little Language'. SEQ-REVIEW represents the first application of the Quality Function Development (QFD) method to sequence software development at JPL. The paper will show how the requirements for SEQ-REVIEW were defined and converted into a design based on object-oriented principles. The process starts with interviews of potential users, a small but diverse group that spans multiple disciplines and 'cultures'. It continues with the development of QFD matrices that related product functions and characteristics to user-demanded qualities. These matrices are then turned into a formal Software Requirements Document (SRD). The process concludes with the design phase, in which the CRC (Class, Responsibility, Collaboration) approach was used to convert requirements into a blueprint for the final product.