Safety, reliability, maintainability, and quality assurance. There appears to be no process of gradually fooling oneself while degrading standards so characteristic of the solid rocket booster or space shuttle main engine safety systems. It is feasible to validate metrics for the purpose of controlling and predicting software quality during design by validating metrics against a quality factor. And were there rigorous tests to avoid software crashes. Space shuttle flight software period themes page 15 pass fsw historyyp divided into periods with consistent environments pass fsw releases page 16 note. The results are given of a survey of software reliability measurement tools performed for the american institute of aeronautics and astronautics aiaa space based observation systems sbos. He is the developer of the schneidewind software reliability model which is used by nasa space shuttle program in the prediction of software reliability, by the naval surface warfare center for trident and tomahawk software reliability prediction, and by the marine corps tactical systems support activity for software reliability assessment. It failed in the goal of achieving reliable access to space, partly due to multiyear interruptions in launches following shuttle failures. Fundamentally, it failed in the goal of reducing the cost of space access.
Criticism of the space shuttle program stemmed from claims that nasas shuttle program failed to achieve its promised cost and utility goals, as well as design, cost, management, and safety issues. The computers also operated the shuttle safely during the launch of columbias sts93 mission in 1999, when an electrical short in a main engine controller and a pinhole leak in a main engine occurred during ascent. Special section paul schneck guest editor design, development. Space shuttle primary flight software system the development of space shuttle software posed unique requirements above and beyond raw size 30 times larger than saturn v software, complexity, and criticality. Pdf software reliability analysis of nasa space flight software.
Its official program name was space transportation system sts, taken from a 1969 plan for a system of reusable spacecraft of which it was the only item funded for development. A practical experience harish sukhwani 1, javier alonso1,2, kishor s. The space shuttle avionics software represents a successful integration of many of the computer industrys most advanced software engineering practices and. In other words, when it comes to flying the shuttle, reliability means far more than performance. The cm data include not only a change itself, but also the lines of code affected, reasons for the change, and the date and time of change. The environment of space is very harsh and unfriendly and not just space, but getting into space, said roscoe ferguson, a space shuttle flight software operating system engineer for the united space alliance. Predictions for increasing confidence in the reliability of the space shuttle flight software. S060935, dated 81297 and s060941, dated 81597 list of effective pages february 28, 2000 the current status of all pages in this document is as shown below. Architecture of the space shuttle primary avionics software system. Software reliability predictions can increase trust in the reliability of safety critical software such as the nasa space shuttle primary avionics software system shuttle flight software.
Safety, reliability, maintainability and quality provisions. Guest editor architecture of the space shuttle primary avionics software system pass, perhaps the most complex flight computer program ever developed, epitomizes the benefits to be gained by establishing a wellstructured system architecture at the front end of the development process gene d. The entire control software for the shuttle is less then one meg. Pdf a survey of software reliability measurement tools. May 22, 2012 software reliability for flight crew training simulators. Criticizing the space shuttle is like punching america in the face. They work for the onboard shuttle group, a branch of lockheed martin corps space mission systems division, and their prowess is world renowned. The suresense software had an immediate assignment. It is shown that three separate but related functions comprise an integrated reliability program. Early in the program it was decided not to use reliability or probability numbers in the design of the shuttle because the magnitude of testing.
Pdf in this paper, we present the software reliability analysis of the flight software of a recently launched space mission. Lps system architecture and antiquated software prevents flexibility and expansion to support shuttle upgrades. This objective was achieved using a novel approach to integrate software safety criteria, risk analysis, reliability prediction, and stopping. Quality factors, like reliability, are of more interest to customers than metrics, like complexity. A case study is then presented of the analysis of failure data from a space. Applying reliability models to the space shuttle ieee.
Predicting shuttle software reliability with parameter evaluation. Read an assessment of space shuttle flight software. How often, if ever, was software updated in the shuttle. The primary avionics software system pass is the missioncritical onboard data processing system for nasas space shuttle fleet.
Man agement procedures have evolved that improved the control and. Along with its unprecedented number of successful flights, space shuttle history also illustrates the potential value of sensor validation. A pilot formal methods approach verified complete software assurance requirements for cassini. Compilers and other tools have been developed to improve productivity and reliability. Moranda introduction and summary software reliability study was initiated by advanced information systems subdivision of mcdonnell douglas astro nautics company, huntington beach, california, to conduct research into the nature of the software reliability problem including definitions, contributing factors and means for control. To ensure high reliability and safety, ibm has designed the space shuttle computer system to have four redundant, synchronized computers, each of which is. Reliability modeling for safety critical software springerlink.
Increasing obsolescence of equipment will continue to drive costs upward and degrade reliability. Richard feynman, the challenger disaster, and software. The space shuttle avionics software represents a successful integration of many of the computer industrys most advanced software engineering practices and successful application of software reliability engineering for the nasa space shuttle ieee conference publication. All told, pass has been in control for over 0 days of orbital. Im not sure what software was in the shuttle orbiters, but was it updated. After all, its been a symbol of national pride for thirty years. For example, in the 1969 nasa space shuttle task group report, the. And yet during a mission as recent as 1992, a space shuttle computer became stymied while executing a program it had run millions of times before. Predicting shuttle software reliability with parameter. Applying reliability models to the space shuttle ieee software. Quality factors, like reliability, are of more interest to customers than metrics, like. With the key hardware problems solved, nasa turned to the task of specifying the most complex flight software ever conceived. A composite description of all space shuttle software of various ages is maintained through a configuration management cm system.
Developing software for the space shuttle 108 during 1973 and 1974 the first requirements began to be specified for what has become one of the most interesting software systems ever designed. To summarize then, the computer software checking system and attitude is of the highest quality. Software reliability models provide one of several tools that software reliability managers of the shuttle flight software are using to provide. Each gpc is composed of two separate units, a central processor unit and an inputoutput processor. Wilcutt also served as nasa director of operations at the yuri gagarin cosmonaut training center in star city, russia. It was obvious from the very beginning that developing the shuttles software would be a complicated job. This will provide the reader with the foundation to understand the basic process of software reliability engineering sre. The us space shuttle the ibm federal services company in huston, selected the shneidewind model to predict the reliability of the shuttles onboard system software for nasa, after evaluating many reliability models and tried to validate them for use on this project. Computers in 1981 were of course significantly inferior to what i had in my phone in 2003.
No flights using releases oi3oi3, oi7candoi7c, and oi8a space shuttle flight rate and key flights page 17. Moreover, software domain reuse principles were applied to wind tunnel control. Apr 18, 2012 criticizing the space shuttle is like punching america in the face. Nasa space shuttle flight control software statistical. The new glass cockpit in the shuttle runs on intel 80386s. Synchronization and redundancy together were the methods chosen to ensure the reliability of the shuttle avionics hardware. In flight, all shuttle control activitiesincluding main engine throttling, directing control jets to turn the vehicle in a different orientation, firing the engines, or providing guidance commands for landingare performed manually or automatically with this. Five identical generalpurpose computers aboard the orbiter control space shuttle vehicle systems. By the time the space shuttle started flying in 1981, the techniques to keep software reliable had advanced. The space shuttle is a partially reusable low earth orbital spacecraft system that was operated from 1981 to 2011 by the u. In early 1991, the national aeronautics and space administrations nasas office of space flight commissioned the aeronautics and space engineering board aseb of the national research council nrc to investigate the adequacy of the current process by which nasa develops and verifies changes and updates to the space shuttle flight software. Programmers have learned how software breaks, according to robert hinson, chief of the shuttle data systems branch at nasas johnson space center in houston. The space shuttles main computer system is wellregarded for its reliability.
Successful application of software reliability engineering. Space shuttle program primaryyy avionics software system. With the sts5 landing, the space shuttle primary avionics software system pass has completed over thirty years of operational service as the brains of the flybywire space shuttle vehicle. Shuttle computers navigate record of reliability nasa. However, quality factors cannot be collected until late in a project. But many of my friends and i are celebrating yesterdays. Im picturing our old 1980s tandy with 640k of memory still operating an incredible space craft in 2003. The space shuttle uses the apa101s computer 5 of them for redundancy. Software reliability analysis of nasa space flight software. Successful application of software reliability engineering for the. Software quality metrics have potential for helping to ensure the quality of software on large projects such as thespace shuttle flight software. Additionally, a quantitative software methods and measurements guidebook was baselined for shuttle and the space operations management office. Guest editor shuttle primary avionics software system. Richard feynman, the challenger disaster, and software engineering feb 20th, 2008 on january 28th, 1986, space shuttle challenger was launched at 11.
Sep 23, 2015 requirement reliability prediction following the loss of the space shuttle challenger and crew in 1986, ibm federal systems division houston as the space shuttle primary avionics software system developer was assigned a return to flight action to model the software reliability of loss of vehicle and crew latent errors defects. Reliability modeling for safetycritical software ieee. The ibm federal services company in huston, selected the shneidewind model to predict the reliability of the shuttle s onboard system software for nasa, after evaluating many reliability models and tried to validate them for use on this project. National aeronautics and space administration nasa as part of the space shuttle program. Mission objectives include safety, mission success and sustainability criteria. Nasa shuttle computers navigate record of reliability.
The space shuttle avionics and pass legacy includes. The experience of a team that evaluated many reliability models and tried to validate them for the onboard system software of the national aeronautics and space administrations nasas space shuttle is presented. The space shuttle primary avionics software subsystem will be used to illustrate the sre process. Successful application of software reliability engineering for the nasa space shuttle.
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