Dale Thomas | University of Alabama in Huntsville (original) (raw)
Papers by Dale Thomas
INCOSE International Symposium, Jul 1, 1998
ABSTRACTEach day, engineers cope with the challenges of building complex systems – challenges whi... more ABSTRACTEach day, engineers cope with the challenges of building complex systems – challenges which place the project cost, schedule, and technical performance at risk. Can a measure of the inherent complexity of a system provide any insights regarding the risk to cost, schedule, and technical performance? Perhaps it can. This paper briefly reviews the development of a complexity metric and subsequently presents results from a validation assessment. These results indicate a significant relation between system complexity and program development cost.
Propulsion Systems - Recent Advances, New Perspectives and Applications [Working Title]
Nuclear propulsion utilizes nuclear reactions to produce energy, which is then used to propel a v... more Nuclear propulsion utilizes nuclear reactions to produce energy, which is then used to propel a vehicle. There are three main forms of nuclear propulsion: naval nuclear propulsion, aero-nuclear propulsion, and space nuclear propulsion. Naval nuclear propulsion involves the use of nuclear reactors to power ships. This propulsion type provides several advantages over traditional propulsion methods, including increased range, speed, and maneuverability. The first nuclear-powered submarine, the USS Nautilus, was commissioned in 1955, and since then, many countries have developed nuclear-powered submarines and ships. Aero-nuclear propulsion involves the use of nuclear reactors to power aircraft or missiles. This concept has been the subject of much research and development. Space nuclear propulsion involves the use of nuclear reactors to power spacecraft. This type of propulsion provides several advantages over traditional propulsion methods, including increased speed and efficiency. The...
AIAA Modeling and Simulation Technologies Conference, 2017
2018 Joint Propulsion Conference, 2018
The overall goal of the 2nd Generation RLV Program is to substantially reduce technical and busin... more The overall goal of the 2nd Generation RLV Program is to substantially reduce technical and business risks associated with developing a new class of reusable launch vehicles. NASA's specific goals are to improve the safety of a 2nd- generation system by 2 orders of magnitude - equivalent to a crew risk of 1 -in- 10,000 missions - and decrease the cost tenfold, to approximately $1,000 per pound of payload launched. Architecture definition is being conducted in parallel with the maturating of key technologies specifically identified to improve safety and reliability, while reducing operational costs. An architecture broadly includes an Earth-to-orbit reusable launch vehicle, on-orbit transfer vehicles and upper stages, mission planning, ground and flight operations, and support infrastructure, both on the ground and in orbit. The systems engineering approach ensures that the technologies developed - such as lightweight structures, long-life rocket engines, reliable crew escape, an...
2018 AIAA Aerospace Sciences Meeting, 2018
53rd AIAA/SAE/ASEE Joint Propulsion Conference, 2017
INCOSE International Symposium, 2018
In order to characterize dysfunction in the execution of the Systems Engineering (SE) process in ... more In order to characterize dysfunction in the execution of the Systems Engineering (SE) process in a more methodical and systematic way, the Systems Science concept of Systems Pathology is extended to Systems Engineering Pathology. Poor SE execution can be due to inadequate execution, insufficient budgets, deficient interfacing, and other factors. These can be addressed by program/project audits and lessons learned. However, applying the science of Systems Pathology can provide a more integrated and methodical approach to address poor SE execution. SE Pathology can provide the holistic approach needed to better characterize dysfunction, for a better chance at intervention, prevention, and ultimately program success. Through a literature review, the logic behind Systems Engineering Pathology is explained and existing Systems Engineering Pathology work is discussed. These sources are aggregated to provide an expanded list of typical SE dysfunctions. Next steps for empirical study are proposed. Transfer of SE Pathology research findings to SE practice is discussed. As medicine has been gradually accumulating an understanding of causes, detection and treatment of diseased states, perhaps SE can begin to accumulate an understanding of causes, detection and treatment of dysfunctional execution. The objective would be to better achieve affordable, healthy SE functions enabled to positively influence program outcomes.
Procedia Computer Science, 2019
System complexity is often associated with multiple issues such as schedule and cost overruns, po... more System complexity is often associated with multiple issues such as schedule and cost overruns, poor performance or even program failure. With engineered systems becoming ever more complex it is of great interest to be able to assess the complexity of a system easily and during the design process. Since Model Based Systems Engineering (MBSE) is becoming a widely used tool in systems development, a method to assess complexity using a SysML model and the information that is typically depicted in a model is developed. The complexity estimation in SysML was done by adapting the complexity metric developed by Sinha and Suh for a Design Structure Matrix (DSM).
NASA's Marshall Space Flight Center (MSFC) management feels that sound system engineering pra... more NASA's Marshall Space Flight Center (MSFC) management feels that sound system engineering practices are essential for successful project management, NASA studies have concluded that recent project failures could be attributed in part to inadequate systems engineering. A recent survey of MSFC project managers and system engineers' resulted in the recognition of a need for training in Systems Engineering Practices, particularly as they relate to MSFC projects. In response to this survey, an internal pilot short-course was developed to reinforce accepted practices for system engineering at MSFC. The desire of the MSFC management is to begin with in-house training and offer additional educational opportunities to reinforce sound system engineering principles to the more than 800 professionals who are involved with system engineering and project management. A Systems Engineering Development Plan (SEDP) has been developed to address the longer-term systems engineering development ...
2018 Joint Propulsion Conference, 2018
Journal of Spacecraft and Rockets, 2019
Nuclear thermal propulsion (NTP) is an enabling technology for expanding spaceflight capability b... more Nuclear thermal propulsion (NTP) is an enabling technology for expanding spaceflight capability beyond cislunar space. Hydrogen propellant is required for best efficiency by mass, but long-term hyd...
Incose International Symposium, Jul 1, 1993
The development of large scale systems necessarily involves a large number of engineering organiz... more The development of large scale systems necessarily involves a large number of engineering organizations, each working individually to design separate components which will ultimately be integrated. If these organizations are to work concurrently, routine and methodological communication between the engineering organizations is required. One necessary product of this communication is the timely specification and design of the components' mating interfaces.The Space Station Freedom (S.S. Freedom) program is a multinational venture, with participating agencies including the National Aeronautics and Space Administration (United States), the National Space Development Agency of Japan, the Canadian Space Agency, the European Space Agency, and the Italian Space Agency. To integrate a project of this scale, with such a large number of participants, a very large quantity of interface development is required to allow the design of the S.S. Freedom's components to proceed concurrently around the world. This paper briefly describes the scope of the system integration task in the S.S. Freedom program and discusses the utilization of an electronic information system specifically developed to facilitate the efficient organization and timely completion of interface design activities.
SAE Technical Paper Series, 1990
INCOSE International Symposium, Jul 1, 1998
ABSTRACTEach day, engineers cope with the challenges of building complex systems – challenges whi... more ABSTRACTEach day, engineers cope with the challenges of building complex systems – challenges which place the project cost, schedule, and technical performance at risk. Can a measure of the inherent complexity of a system provide any insights regarding the risk to cost, schedule, and technical performance? Perhaps it can. This paper briefly reviews the development of a complexity metric and subsequently presents results from a validation assessment. These results indicate a significant relation between system complexity and program development cost.
Propulsion Systems - Recent Advances, New Perspectives and Applications [Working Title]
Nuclear propulsion utilizes nuclear reactions to produce energy, which is then used to propel a v... more Nuclear propulsion utilizes nuclear reactions to produce energy, which is then used to propel a vehicle. There are three main forms of nuclear propulsion: naval nuclear propulsion, aero-nuclear propulsion, and space nuclear propulsion. Naval nuclear propulsion involves the use of nuclear reactors to power ships. This propulsion type provides several advantages over traditional propulsion methods, including increased range, speed, and maneuverability. The first nuclear-powered submarine, the USS Nautilus, was commissioned in 1955, and since then, many countries have developed nuclear-powered submarines and ships. Aero-nuclear propulsion involves the use of nuclear reactors to power aircraft or missiles. This concept has been the subject of much research and development. Space nuclear propulsion involves the use of nuclear reactors to power spacecraft. This type of propulsion provides several advantages over traditional propulsion methods, including increased speed and efficiency. The...
AIAA Modeling and Simulation Technologies Conference, 2017
2018 Joint Propulsion Conference, 2018
The overall goal of the 2nd Generation RLV Program is to substantially reduce technical and busin... more The overall goal of the 2nd Generation RLV Program is to substantially reduce technical and business risks associated with developing a new class of reusable launch vehicles. NASA's specific goals are to improve the safety of a 2nd- generation system by 2 orders of magnitude - equivalent to a crew risk of 1 -in- 10,000 missions - and decrease the cost tenfold, to approximately $1,000 per pound of payload launched. Architecture definition is being conducted in parallel with the maturating of key technologies specifically identified to improve safety and reliability, while reducing operational costs. An architecture broadly includes an Earth-to-orbit reusable launch vehicle, on-orbit transfer vehicles and upper stages, mission planning, ground and flight operations, and support infrastructure, both on the ground and in orbit. The systems engineering approach ensures that the technologies developed - such as lightweight structures, long-life rocket engines, reliable crew escape, an...
2018 AIAA Aerospace Sciences Meeting, 2018
53rd AIAA/SAE/ASEE Joint Propulsion Conference, 2017
INCOSE International Symposium, 2018
In order to characterize dysfunction in the execution of the Systems Engineering (SE) process in ... more In order to characterize dysfunction in the execution of the Systems Engineering (SE) process in a more methodical and systematic way, the Systems Science concept of Systems Pathology is extended to Systems Engineering Pathology. Poor SE execution can be due to inadequate execution, insufficient budgets, deficient interfacing, and other factors. These can be addressed by program/project audits and lessons learned. However, applying the science of Systems Pathology can provide a more integrated and methodical approach to address poor SE execution. SE Pathology can provide the holistic approach needed to better characterize dysfunction, for a better chance at intervention, prevention, and ultimately program success. Through a literature review, the logic behind Systems Engineering Pathology is explained and existing Systems Engineering Pathology work is discussed. These sources are aggregated to provide an expanded list of typical SE dysfunctions. Next steps for empirical study are proposed. Transfer of SE Pathology research findings to SE practice is discussed. As medicine has been gradually accumulating an understanding of causes, detection and treatment of diseased states, perhaps SE can begin to accumulate an understanding of causes, detection and treatment of dysfunctional execution. The objective would be to better achieve affordable, healthy SE functions enabled to positively influence program outcomes.
Procedia Computer Science, 2019
System complexity is often associated with multiple issues such as schedule and cost overruns, po... more System complexity is often associated with multiple issues such as schedule and cost overruns, poor performance or even program failure. With engineered systems becoming ever more complex it is of great interest to be able to assess the complexity of a system easily and during the design process. Since Model Based Systems Engineering (MBSE) is becoming a widely used tool in systems development, a method to assess complexity using a SysML model and the information that is typically depicted in a model is developed. The complexity estimation in SysML was done by adapting the complexity metric developed by Sinha and Suh for a Design Structure Matrix (DSM).
NASA's Marshall Space Flight Center (MSFC) management feels that sound system engineering pra... more NASA's Marshall Space Flight Center (MSFC) management feels that sound system engineering practices are essential for successful project management, NASA studies have concluded that recent project failures could be attributed in part to inadequate systems engineering. A recent survey of MSFC project managers and system engineers' resulted in the recognition of a need for training in Systems Engineering Practices, particularly as they relate to MSFC projects. In response to this survey, an internal pilot short-course was developed to reinforce accepted practices for system engineering at MSFC. The desire of the MSFC management is to begin with in-house training and offer additional educational opportunities to reinforce sound system engineering principles to the more than 800 professionals who are involved with system engineering and project management. A Systems Engineering Development Plan (SEDP) has been developed to address the longer-term systems engineering development ...
2018 Joint Propulsion Conference, 2018
Journal of Spacecraft and Rockets, 2019
Nuclear thermal propulsion (NTP) is an enabling technology for expanding spaceflight capability b... more Nuclear thermal propulsion (NTP) is an enabling technology for expanding spaceflight capability beyond cislunar space. Hydrogen propellant is required for best efficiency by mass, but long-term hyd...
Incose International Symposium, Jul 1, 1993
The development of large scale systems necessarily involves a large number of engineering organiz... more The development of large scale systems necessarily involves a large number of engineering organizations, each working individually to design separate components which will ultimately be integrated. If these organizations are to work concurrently, routine and methodological communication between the engineering organizations is required. One necessary product of this communication is the timely specification and design of the components' mating interfaces.The Space Station Freedom (S.S. Freedom) program is a multinational venture, with participating agencies including the National Aeronautics and Space Administration (United States), the National Space Development Agency of Japan, the Canadian Space Agency, the European Space Agency, and the Italian Space Agency. To integrate a project of this scale, with such a large number of participants, a very large quantity of interface development is required to allow the design of the S.S. Freedom's components to proceed concurrently around the world. This paper briefly describes the scope of the system integration task in the S.S. Freedom program and discusses the utilization of an electronic information system specifically developed to facilitate the efficient organization and timely completion of interface design activities.
SAE Technical Paper Series, 1990