Engineering design is a challenging activity for any product. Since launch vehicles are highly complex and interconnected and have extreme energy densities, their design represents a challenge of the highest order. The purpose of this document is to delineate and clarify the design process associated with the launch vehicle for space flight transportation. The goal is to define and characterize a baseline for the space transportation design process. This baseline can be used as a basis for improving effectiveness and efficiency of the design process. The baseline characterization is achieved via compartmentalization and technical integration of subsystems, design functions, and discipline functions. First, a global design process overview is provided in order to show responsibility, interactions, and connectivity of overall aspects of the design process. Then design essentials are delineated in order to emphasize necessary features of the design process that are sometimes overlooked. Finally the design process characterization is presented. This is accomplished by considering project technical framework, technical integration, process description (technical integration model, subsystem tree, design/discipline planes, decision gates, and tasks), and the design sequence. Also included in the document are a snapshot relating to process improvements, illustrations of the process, a survey of recommendations from experienced practitioners in aerospace, lessons learned, references, and a bibliography. Blair, J. C. and Ryan, R. S. and Schutzenhofer, L. A. and Humphries, W. R. Marshall Space Flight Center

The advent of commercial launch systems has brought about a new age of space launch vehicle design. In order to survive in a competitive market, space launch providers must design systems with new technologies in shorter development times. This changing nature of space launch vehicle design requires a new way to perform safety analysis. Traditional hazard analysis techniques do not deliver adequate insight early in the design process, when most of the safety-related decisions are made. Early design decisions are often made using "lessons-learned" from previous launch systems, rather than interactive feedback from the new vehicle design actually being developed. Furthermore, traditional techniques use reliability theory as their foundation, resulting in the use of excessive design margin and redundancy as the "default" vehicle design choices. This equivocation of safety and reliability may have made sense for simpler launch vehicles of the past, but most modern space launch vehicle accidents have resulted from incorrect software specifications, component interaction accidents, and other design errors independent of the reliability of individual components. The space launch industry needs safety analysis methods and design processes that identify and correct these hazards early in the vehicle design process, when modifications to correct safety issues are more effective and less costly. This work shows how Systems-Theoretic Process Analysis (STPA) can been used as a powerful tool to identify, mitigate, and possibly eliminate hazards throughout the entire space launch vehicle lifecycle. This work begins by reviewing traditional hazard analysis techniques and the changing nature of launch vehicle accidents. Next, it describes how STPA can be integrated into the space launch vehicle lifecycle to design safer systems. It then demonstrates the safety-guided design of a small-lift launch vehicle using STPA. Finally, this work shows how STPA can be used to satisfy regulatory and range safety requirements. The thesis of this work is that integration of STPA into the design of space launch vehicles can make a significant contribution to reducing launch vehicle accidents.

The NASA Technical Reports Server (NTRS) houses half a million publications that are a valuable means of information to researchers, teachers, students, and the general public. These documents are all aerospace related with much scientific and technical information created or funded by NASA. Some types of documents include conference papers, research reports, meeting papers, journal articles and more. This is one of those documents.

A primary NASA priority is to reduce the cost and improve the effectiveness of launching payloads into space. As a consequence, significant improvements are being sought in the effectiveness, cost, and schedule of the launch vehicle design process. In order to provide a basis for understanding and improving the current design process, a model has been developed for this complex, interactive process, as reported in the references. This model requires further expansion in some specific design functions. Also, a training course for less-experienced engineers is needed to provide understanding of the process, to provide guidance for its effective implementation, and to provide a basis for major improvements in launch vehicle design process technology. The objective of this activity is to expand the description of the design process to include all pertinent design functions, and to develop a detailed outline of a training course on the design process for launch vehicles for use in educating engineers whose experience with the process has been minimal. Building on a previously-developed partial design process description, parallel sections have been written for the Avionics Design Function, the Materials Design Function, and the Manufacturing Design Function. Upon inclusion of these results, the total process description will be released as a NASA TP. The design function sections herein include descriptions of the design function responsibilities, interfaces, interactive processes, decisions (gates), and tasks. Associated figures include design function planes, gates, and tasks, along with other pertinent graphics. Also included is an expanded discussion of how the design process is divided, or compartmentalized, into manageable parts to achieve efficient and effective design. A detailed outline for an intensive two-day course on the launch vehicle design process has been developed herein, and is available for further expansion. The course is in an interactive lecture/wor