Architecting the Communication and Navigation Networks for NASA's Space Exploration Systems

NASA is planning a series of short and long duration human and robotic missions to explore the Moon and then Mars. A key objective of the missions is to grow, through a series of launches, a system of systems communication, navigation, and timing infrastructure at minimum cost while providing a network-centric infrastructure that maximizes the exploration capabilities and science return. There is a strong need to use architecting processes in the mission pre-formulation stage to describe the systems, interfaces, and interoperability needed to implement multiple space communication systems that are deployed over time, yet support interoperability with each deployment phase and with 20 years of legacy systems. In this paper we present a process for defining the architecture of the communications, navigation, and networks needed to support future space explorers with the best adaptable and evolable network-centric space exploration infrastructure. The process steps presented are: 1) Architecture decomposition, 2) Defining mission systems and their interfaces, 3) Developing the communication, navigation, networking architecture, and 4) Integrating systems, operational and technical views and viewpoints. We demonstrate the process through the architecture development of the communication network for upcoming NASA space exploration missions

Achieving Alignment: An Analysis of Enterprise Architecture Best Practices within the United States Air Force

This research uncovers areas of best practices that support achieving alignment between an organization’s Information Technology (IT) and its business processes. One principal finding of this effort revealed that the means used to achieve alignment exists within the effective application of Enterprise Architecture (EA), a common practice found throughout the Federal Government, Department of Defense, and the Air Force. EA is the tool used to achieve alignment; likewise, the reason for developing IT architecture is to achieve alignment of IT investments and mission objectives. This research groups the best practices into vision, identification, framework, and governance. Interestingly, these practices relate to an Enterprise Architecture’s depiction of the to be target state, the as is baseline, the tools and models used for communication, and the motivation and management of the transition plan. The insights achieved by this research should strengthen the use of Enterprise Architecture within the Air Force by enabling senior leaders and decision-makers to align strategy and IT investment towards improving mission accomplishment

Computational intelligence based complex adaptive system-of-systems architecture evolution strategy

The dynamic planning for a system-of-systems (SoS) is a challenging endeavor. Large scale organizations and operations constantly face challenges to incorporate new systems and upgrade existing systems over a period of time under threats, constrained budget and uncertainty. It is therefore necessary for the program managers to be able to look at the future scenarios and critically assess the impact of technology and stakeholder changes. Managers and engineers are always looking for options that signify affordable acquisition selections and lessen the cycle time for early acquisition and new technology addition. This research helps in analyzing sequential decisions in an evolving SoS architecture based on the wave model through three key features namely; meta-architecture generation, architecture assessment and architecture implementation. Meta-architectures are generated using evolutionary algorithms and assessed using type II fuzzy nets. The approach can accommodate diverse stakeholder views and convert them to key performance parameters (KPP) and use them for architecture assessment. On the other hand, it is not possible to implement such architecture without persuading the systems to participate into the meta-architecture. To address this issue a negotiation model is proposed which helps the SoS manger to adapt his strategy based on system owners behavior. This work helps in capturing the varied differences in the resources required by systems to prepare for participation. The viewpoints of multiple stakeholders are aggregated to assess the overall mission effectiveness of the overarching objective. An SAR SoS example problem illustrates application of the method. Also a dynamic programing approach can be used for generating meta-architectures based on the wave model. --Abstract, page iii

Supply Chain Interoperability Measurement

Academia recognizes that although supply chains have an inherent need to be validated for their performance, supply chain performance measurement systems are still inadequate and one of the major barriers to successful supply chain collaboration. In this research, theory of Systems Architecture is used to make the first step towards an innovative supply chain performance measure defined as supply chain interoperability. Interoperability is considered a similarity metric with regard to a set of deterministic and stochastic characters (criteria) describing supply chain participants, a methodology that adapts and expands an interoperability measurement tool initially developed in and for a military context. A process that could be used to develop a set of initial supply chain interoperability characters to be included in the interoperability measurement is demonstrated based on interviews from managers of various functional roles at a single defense company in Greece. The presented measurement methodology can assist in efficiently directing resources to best improve interoperability between and among the various elements of a supply chain

Building Enterprise Transition Plans Through the Development of Collapsing Design Structure Matrices

The United States Air Force (USAF), like many other large enterprises, has evolved over time, expanded its capabilities and has developed focused, yet often redundant, operational silos, functions and information systems (IS). Recent failures in enterprise integration efforts herald a need for a new method that can account for the challenges presented by decades of increases in enterprise complexity, redundancy and Operations and Maintenance (O&M) costs. Product or system-level research has dominated the study of traditional Design Structure Matrices (DSMs) with minimal coverage on enterprise-level issues. This research proposes a new method of collapsing DSMs (C-DSMs) to illustrate and mitigate the problem of enterprise IS redundancy while developing a systems integration plan. Through the use of iterative user constraints and controls, the C-DSM method employs an algorithmic and unbiased approach that automates the creation of a systems integration plan that provides not only a roadmap for complexity reduction, but also cost estimates for milestone evaluation. Inspired by a recent large IS integration program, an example C-DSM of 100 interrelated legacy systems was created. The C-DSM method indicates that if a slow path to integration is selected then cost savings are estimated to surpass integration costs after several iterations

Value network modeling : a quantitative method for comparing benefit across exploration architectures

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; and, (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 167-170).In the design of complex systems serving a broad group of stakeholders, it can be difficult to prioritize objectives for the architecture. I postulate that it is possible to make architectural decisions based on consideration of stakeholder value delivery, in order to help prioritize objectives. I introduce the concept of value network models to map out the indirect benefit delivered to stakeholders. A numerical methodology for prioritizing paths through this network model is presented, with a view to discovering the most important organizational outputs. I show how value network models can be linked to architecture models to provide decision support to the architect. I present a case study to examine the connectivity and sensitivity of a test architecture to value delivery. I conclude that a limited subset of NASA's outputs will discriminate between architectures. In this manner, I show how value considerations can be used to structure the design space before critical technical decisions are made to narrow it. A number of organizational implications for value delivery are generated from this analysis. In particular, I show that benefit flows should be aligned to organizational processes and responsibilities, and that failure to map stakeholder input to architecture evaluation can weaken benefit.by Bruce G. Cameron.S.M

Incorporating modern development and evaluation techniques into the creation of large-scale, spacecraft control software

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2006.Includes bibliographical references (p. 165-172).One of the major challenges facing the development of today's safety- and mission-critical space systems involves the construction of software to support the goals and objectives of these missions, especially those associated with NASA's Space Exploration Initiative, which has now become the focus of the US Space Program and its contractors. Consequently, the software used to implement much of the functionality in the various flight vehicles and ground facilities must be given special consideration. This dissertation outlines a new approach to spacecraft software development that focuses on incorporating modem software engineering techniques into the spacecraft domain including (1) a product-line approach to the software development enterprise and (2) a software architecture-centric design process to support that approach. The new product-line approach is demonstrated through its application to the Exploration Initiative. The technical and managerial aspects of the product line, which are required to successfully field the line, are described in detail. Among the technical artifacts developed to support the line, the software architecture is the most important.(cont.) Consequently, it was necessary to create a systems engineering-based development, evaluation, and selection process for the construction of the software product-line architecture. This development approach is known as Multi-Attribute Software Architecture Trade Analysis (MASATA) and is demonstrated on the vehicles and facilities of the Exploration Initiative, the Crew Exploration Vehicle in particular. Based on the functional requirements of the Exploration Initiative and the quality attributes desired by the stakeholders, a software product line architecture is presented. The desired quality attributes include analyzability with respect to safety, ease of verification and validation, sustainability, affordability, buildability, ability to meet real-time requirements and constraints, and "monitor"-ability. Several architectural style options were selected for evaluation with respect to the requirements and attributes through MASATA including traditional subsystem-based decomposition, state analysis, functional decomposition and implicit invocation. The conceptual software product-line architecture selected to support the Exploration Initiative is based upon these results.by Kathryn Anne Weiss.Ph.D

Exploiting the power of multiplicity: a holistic survey of network-layer multipath

The Internet is inherently a multipath network: For an underlying network with only a single path, connecting various nodes would have been debilitatingly fragile. Unfortunately, traditional Internet technologies have been designed around the restrictive assumption of a single working path between a source and a destination. The lack of native multipath support constrains network performance even as the underlying network is richly connected and has redundant multiple paths. Computer networks can exploit the power of multiplicity, through which a diverse collection of paths is resource pooled as a single resource, to unlock the inherent redundancy of the Internet. This opens up a new vista of opportunities, promising increased throughput (through concurrent usage of multiple paths) and increased reliability and fault tolerance (through the use of multiple paths in backup/redundant arrangements). There are many emerging trends in networking that signify that the Internet's future will be multipath, including the use of multipath technology in data center computing; the ready availability of multiple heterogeneous radio interfaces in wireless (such as Wi-Fi and cellular) in wireless devices; ubiquity of mobile devices that are multihomed with heterogeneous access networks; and the development and standardization of multipath transport protocols such as multipath TCP. The aim of this paper is to provide a comprehensive survey of the literature on network-layer multipath solutions. We will present a detailed investigation of two important design issues, namely, the control plane problem of how to compute and select the routes and the data plane problem of how to split the flow on the computed paths. The main contribution of this paper is a systematic articulation of the main design issues in network-layer multipath routing along with a broad-ranging survey of the vast literature on network-layer multipathing. We also highlight open issues and identify directions for future work