The necessity of functional analysis for space exploration programs
The necessity of functional analysis for space exploration programs
复制标题
空间探索计划泛函分析的必要性
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
J. Breidenthal
中科院分区：
文献类型：
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作者：
A. Terry Morris;J. Breidenthal
随着NASA在其载人探索能力范围内扩大商业航天，越来越强调如何在政府和商业组织之间分配责任，以实现协调的计划目标。程序级功能分析的实践提供了一个机会，提高异构合作伙伴之间的协作功能的理解。功能分析与物理分析相比，更常见的程序级，并提供理论性能，风险和安全的优势，有利于政府-商业伙伴关系。性能优势包括更快地收敛到可接受的系统解决方案;通过用功能冗余代替物理冗余来实现鲁棒性和安全性目标，发现具有更高通用性、更高简单性和更高并行性的上级解决方案;以及围绕计划目标的更大组织凝聚力。风险优势包括：在系统被指定、设计、构建或集成之前，通过揭示某些类型的架构和合同不匹配来避免返工;通过更完整和精确的成本和进度估计规范来避免成本和进度增长;以及在第一次尝试时成功集成的可能性更高。安全方面的优势包括有效地划分综合危险分析的必须工作和不能工作的功能，能够正式证明安全分析的完整性，以及可证明的正确逻辑，以证明飞行准备就绪。实现这些好处的关键机制是在程序级开发一个功能间的体系结构，它揭示了顶层系统需求之间的关系，否则只使用物理体系结构是不可见的。本文介绍了功能分析的优点和缺陷，作为协调空间探索计划的大型异构组织的行动的一种手段。
As NASA moves toward expanded commercial spaceflight within its human exploration capability, there is increased emphasis on how to allocate responsibilities between government and commercial organizations to achieve coordinated program objectives. The practice of program-level functional analysis offers an opportunity for improved understanding of collaborative functions among heterogeneous partners. Functional analysis is contrasted with the physical analysis more commonly done at the program level, and is shown to provide theoretical performance, risk, and safety advantages beneficial to a government-commercial partnership. Performance advantages include faster convergence to acceptable system solutions; discovery of superior solutions with higher commonality, greater simplicity and greater parallelism by substituting functional for physical redundancy to achieve robustness and safety goals; and greater organizational cohesion around program objectives. Risk advantages include avoidance of rework by revelation of some kinds of architectural and contractual mismatches before systems are specified, designed, constructed, or integrated; avoidance of cost and schedule growth by more complete and precise specifications of cost and schedule estimates; and higher likelihood of successful integration on the first try. Safety advantages include effective delineation of must-work and must-not-work functions for integrated hazard analysis, the ability to formally demonstrate completeness of safety analyses, and provably correct logic for certification of flight readiness. The key mechanism for realizing these benefits is the development of an inter-functional architecture at the program level, which reveals relationships between top-level system requirements that would otherwise be invisible using only a physical architecture. This paper describes the advantages and pitfalls of functional analysis as a means of coordinating the actions of large heterogeneous organizations for space exploration programs.