Roadmap for a Human Rated Space Vehicle Flight Software Test Stand

Paper number

IAC-08.D1.5.4

Author

Mr. William Davidson, United Space Alliance, LLC, United States

Year

2008

Abstract

The Space Shuttle has over a 30-year legacy of information that future human rated space vehicle projects would be well served to understand and study. This information is invaluable as a baseline of knowledge of what worked well and not so well. Future projects can use this information to ramp up smoothly and have great endurance. This paper focuses on the simulator used to test the flight software that runs in the General Purpose Computers (GPCs) in the Space Shuttle Orbiter. The primary user and creators of this simulator were the first Software Engineering Institute (SEI) level 5 rated software group. Since that time the SEI system has morphed into the Capability Maturity Model Integration (CMMI) system, and both the users and maintainers of this simulator are CMMI level 5 rated.

This simulator has its origins as the original and current simulator used for GPC flight software development and verification for the entire Shuttle project, lasting over 30 years. During that time, the simulator has grown and matured into a highly efficient, dependable, stable, deterministic and accurate tool to verify the GPC flight software. The technology used in the current simulator is obsolete when compared to modern day computing power, however, a recent project of modifying it to be the primary verification facility for Cockpit Avionics Upgrade (CAU) showed that the methods and philosophies can be seamlessly integrated and utilized with modern technology.

This paper presents the requirements and operational concepts of this simulator and a picture of the methods and philosophies used to satisfy those requirements and concepts. Utilizing knowledge gained by the support of both GPC verification and the integration of CAU, this paper presents a roadmap of the best way to support users during the inception of flight software development all the way through long-term maintenance. Throughout the paper are parallel illustrations of how the methods and philosophies were implemented using 1970-1980’s technology for GPC support and 21st Century technologies for CAU support. Most of the experience this simulator has is with long-term maintenance, which is often a largely overlooked piece of simulator development. The paper shows how a smart approach in the beginning greatly simplifies the costs of long-term maintenance. This paper concludes with an examination of some modern tools and techniques for flight software test stands and leaves the reader with considerations and suggestions of using those tools and techniques in a long-term maintenance environment.



Copyright © 2008 by United Space Alliance, LLC.

Abstract document

IAC-08.D1.5.4.pdf

Manuscript document

IAC-08.D1.5.4.pdf (🔒 authorized access only).

To get the manuscript, please contact IAF Secretariat.