Joyce Warmkessel

Multi-Attribute Tradespace Exploration as Front End for Effective Space System Design

The inability to approach systematically the high level of ambiguity present in the early design phases of space systems causes long, highly iterative, and costly design cycles. A process is introduced and described to capture decision maker preferences and use them to generate and evaluate a multitude of space system designs, while providing a common metric that can be easily communicated throughout the design enterprise. Communication channeled through formal utility interviews and analysis enables engineers to better understand the key drivers for the system and allows for a more thorough exploration of the design tradespace. Multi-attribute tradespace exploration with concurrent design, a process incorporating decision theory into model- and simulation-based design, has been applied to several space system projects at the Massachusetts Institute of Technology. Preliminary results indicate that this process can improve the quality of communication to resolve more quickly project ambiguity and to enable the engineer to discover better value designs for multiple stakeholders. The process is also integrated into a concurrent design environment to facilitate the transfer of knowledge of important drivers into higher fidelity design phases. Formal utility theory provides a mechanism to bridge the language barrier between experts of different backgrounds and differing needs, for example, scientists, engineers, managers, etc. Multi-attribute tradespace exploration with concurrent design couples decision makers more closely to the design and, most important, maintains their presence between formal reviews.

New Methods for Rapid Architecture Selection and Conceptual Design

New methods for rapid front-end development of complex systems are introduced. New tradespace exploration techniques, advances in integrated concurrent engineering, and application of risk analysis methods early in the design process allow rapid progress from poorly defined user needs to fairly detailed conceptual designs. An overview is provided of the methods. A process is described that allows thousands of system architecture alternatives to be quickly and quantitatively assessed vs user needs. The result is an understanding of the tradespace, including its key constraints and sensitivities, as well as an optimum architecture. This architecture is used to specify needs for space vehicles, which are designed using integrated concurrent engineering techniques. Research in risk and uncertainty, policy impacts, and information technology methods allows quantitative consideration of these factors, resulting in designs that are robust to uncertainties and policy impacts and potentially more versatile and flexible. Eight systems designed to date using the method are briefly reviewed. Key literature and a number of companion papers that go into depth on various aspects of the method are cited.

Creating advanced architectures for space systems: Emergent lessons from new processes

Techniques are considered for developing clean sheet designs of advanced architectures for space systems. The terrestrial observer swarm A, an ionospheric mapping system using a swarm of small satellites, is used as an example. A process for exploring open-ended trade spaces is briefly described, and its application to the system followed. The utilities and costs of 1380 possible architectures are calculated. The trade space is explored; the two primary missions of the system are found to drive the architecture in opposite directions, suggesting a rethinking of the mission mix. This tension is coupled to the available funding level because larger, more expensive swarms can do both missions. The process is observed to require careful definition of a set of utility metrics to capture user needs, and updating of the design parameter set to be explored, as understanding of the system and its technical challenges emerges. Overall, both the process used and the swarm technology considered are found to be useful for defining and understanding a large set of available architectures.

CREATING ADVANCED ARCHITECTURES FOR SPACE SYSTEMS: PRODUCT AND PROCESS

Techniques are considered for developing clean sheet designs of advanced architectures for space systems. The A-TOS system, an ionospheric mapping system using a swarm of small satellites, is used as an example. A process for exploring open ended trade spaces is briefly described, and its application to A-TOS followed. The utilities and costs of 1380 possible architectures are calculated. The trade space is explored; the two primary missions of the A-TOS system are found to drive the architecture in opposite directions, suggesting a rethinking of the mission mix. This tension is coupled with the available funding level, as larger, more expensive swarms can do both missions. The process is observed to require frequent updating of the utility functions used to capture user needs, and revisiting of the design parameter set to be explored, as understanding of the system and its technical challenges emerges. Overall, both the process used and the swarm-based architectures considered are found to be useful in defining and understanding a large set of available architectures.

Islands of Success

The journey to lean for the US Aerospace Enterprise began in earnest in the early 1990s, as industry and government responded to post-Cold War imperatives. Most organizations responded first by harvesting the ‘low-hanging fruit’ — opportunities that required minimum investment and that would yield quick results. Often, these resided on the factory floor, where it was felt that rapid improvements in production processes could be implemented. To be sure, there were some more far-reaching change initiatives — ‘pilot projects’ — where a measured industry or government investment could show progress and serve as a powerful illustration of new principles and practices. But going after the ‘low-hanging fruit’ was most common.

An educational experience in developing conceptual architectures for complex systems

Front-end design, from poorly defined user needs to conceptual design, is difficult to do, and difficult to teach. The process itself is typically experience-based and ad-hoc. Attempts to define a formal, teachable process are often unrealistic. Here, a new process is described, as well as a course built on using it as an educational experience. The process uses modeling to systematize architecture selection and conceptual design, using low fidelity, carefully scoped models. The course focuses on using the process to develop a novel, complex space system architecture to address a realistic need. The course was successful in both implementing the process and accelerating learning. An analysis reveals that it moves intuition-based decisions forward, from choosing the design (difficult for students, and limiting in terms of creative designs) to defining the models used to evaluate potential designs, and scoping of the design space explored. Lessons learned from difficulties encountered are also noted.

The 21st-Century Enterprise Challenge

The core challenge for industries in the 21st century involves identifying and delivering value to every stakeholder. Meeting that challenge requires lean capability at the enterprise level.

A Value-Creation Framework

Successful enterprises must not only do the job right: they must do the right job. Becoming lean, as traditionally defined, is important, but it is only part of the story. More important is to use lean concepts and approaches to create value for all stakeholders for all enterprise missions. That’s the essence of our Chapter 1 principles.

The Cold War Legacy

From its modest beginnings at Kitty Hawk — and even earlier, in da Vinci’s sketches — the urge to defy gravity inspired what has since become the aerospace field. And from that moment when we were able to fly, humans have sought to go higher, faster, and farther. This quest was never more manifest than during the decades after World War II, as US national defense and prestige, along with increasing demands for transporting people and goods, drove tremendous growth in the US Aerospace Enterprise — that national community of aerospace firms, US government executive agencies and departments, Congressional committees, professional organizations, universities, and labor unions.

Value in Corporate and Government Enterprises

Creating value at the level of a corporation, government agency, or other multi-program enterprise has long been a challenge. But when companies such as Martin Marietta, McDonnell Douglas, Texas Instruments, and myriad less well-known enterprises are merging or restructuring, and once-familiar names have disappeared altogether, a new sense of urgency grows. How can value best be created at this level? The challenge is large, the stakeholders are many, and this is where multiple value streams come together — each with independent and sometimes conflicting goals.