The National Aeronautics and Space Administration (NASA) has embarked on an ambitious program to return humans to the moon and beyond. As NASA moves forward in the development and design of new launch vehicles for future space exploration, it must fully consider the implications that rule-based requirements of redundancy or fault tolerance have on system reliability/risk. These considerations include common cause failure, increased system complexity, combined serial and parallel configurations, and the impact of design features implemented to control premature activation. These factors and others must be considered in trade studies to support design decisions that balance safety, reliability, performance and system complexity to achieve a relatively simple, operable system that provides the safest and most reliable system within the specified performance requirements. This paper describes conditions under which additional functional redundancy can impede improved system reliability. Examples from current NASA programs including the Ares I Upper Stage will be shown.
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机译：美国国家航空航天局（NASA）已着手一项雄心勃勃的计划，将人类送回月球及其他地方。随着NASA在开发和设计用于未来太空探索的新型运载火箭方面不断前进，它必须充分考虑基于规则的冗余或容错要求对系统可靠性/风险的影响。这些考虑因素包括常见原因故障，增加的系统复杂性，组合的串行和并行配置，以及为控制过早激活而实施的设计功能的影响。在贸易研究中必须考虑这些因素和其他因素，以支持平衡安全性，可靠性，性能和系统复杂性的设计决策，以实现相对简单，可操作的系统，从而在规定的性能要求内提供最安全，最可靠的系统。本文介绍了在哪些情况下附加功能冗余会阻碍系统可靠性的提高。将显示当前NASA计划的示例，包括Ares I Upper Stage。
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