David H. Richardson | Engineering Papers

NASA NTRSDate not supplied

A Model-Based Framework for NASA Science Mission Formulation

This paper details an effort to implement NASA systems engineering standards and practices using a Digital System Model (DSM), which we also refer to as the system architecture model (SAM). Creating a SAM at the beginning of a design effort helps systems engineer identify errors, inconsistencies, and miscommunications as early as possible. Such issues can then be resolved before it becomes costly and requires significant rework to do so. A pre-formulation SAM also enables advanced trade studies at the earliest stage of concept development. This results in “win-wins” where architecture changes can reduce cost without decreasing effectiveness, or increase effectiveness without increasing cost. SAMs also streamline the creation of project documentation and facilitate superior dialogue between science, engineering, and management stakeholders. Common artifacts such as Master Equipment Lists (MELs), Science Traceability Matrices (STMs), and Mission Traceability Matrices (MTMs), can be automatically maintained through requirements and structural models in the SAM. Key performance parameters (and changes to them) can be tied to simulations in the SAM, allowing far more rapid and extensive trade space exploration. As will be shown in this work, these advantages have been realized for the first time in an actual NASA Goddard Space Flight Center (GSFC) pre-phase A and phase A concept study. Modelbased design tools have been developed in a general, modular manner to maximize reuse on future programs. Focus is placed on structural and requirements architecture modeling. Data is ingested into the SAM from existing discipline model outputs (e.g. MS Excel spreadsheets) and used to update a SysML structural model. A mission requirements model is created within the SAM, containing mission specific as well as standard GSFC mission requirements. With the linked requirements model and structural model, automated compliance checking will be performed as mission parameters evolve without the need for discipline engineers to work directly with the SAM in SysML.

MBSE↗

NASA NTRSDate not supplied

NASA’s Four-Layer Cake: Systematic Approach for Developing a Digital Transformation Tactical Plan for Organizations

With the current industry movement to “digitally transform” there is much fervor to do something, to change in some way, to do things differently and digitally; however, the last decade has shown that most organizations do not know where to start or abandon transformation efforts. And often the approaches taken fall in the realm of “low-hanging fruit” or “easy wins” which rarely result in the foundational change needed. NASA was no different in the early years of its digital transformation and this drove the development of what eventually became known as the “Four-Layer Cake”. The Four-Layer Cake provides the critical approach for determining the core areas for investment to gain the greatest return without having to boil the ocean or hope that the low-hanging fruit will provide the foundational elements for a domain’s transformation.

Digital engineering↗