• ELS Home
• SIMA
• Atmosphere Revitalization
• Water Recovery
• Waste Management
• Habitation Engineering
• V&T - Flight Experiments
• V&T - Integrated Testing
• Education & Outreach

SYSTEMS INTEGRATION, MODELING AND ANALYSIS (SIMA)

SIMA is a multi-center ELS organization that studies, develops, applies, and maintains methods of systems analysis and engineering for exploration life support systems. SIMA capabilities and efforts are used to guide investments in research and technology development, resolve and integrate competing requirements, and guide evolution of life support system architecture.

SIMA studies the flow of mass and energy throughout candidate Environmental Control and Life Support Systems (ECLSS), the functions required within the system, and the technologies that can perform those functions.

Tasks

SIMA activities can be grouped into several primary areas:

Conduct analyses of life support systems to predict performance, optimize technology implementation and the life support system architecture, perform trade-off and break-even studies.

SIMA performs analyses at many levels of detail, including detailed transient simulations of specific hardware, simulations of integrated life support systems and key interfaces, or top-level sizing estimates based on steady state performance. These analyses can be used to compare two technologies proposed for the same function, optimize a life support system in light of changing drivers or requirements from interfacing systems, or provide general guidance as to when implementing resource recovery functions may pay-off for life support systems for a given type of mission, and more.

Develop Program-level reference documentation of mission architectures, system and technology requirements, and technology design parameter guidelines.

SIMA develops and maintains several key documents for ELS. These include the Reference Missions Document, the Requirements Document, and the Baseline Values and Assumptions Document. These documents help engineers and other researchers, analysts, and managers focus their efforts on the most relevant expected applications for new technologies in the dynamic and uncertain environment that is inherently part of technology development.

Develop and implement tools to accumulate and centralize technology and project data, promote technology developer collaboration, and compute Project-level reporting metrics.

Maintaining critical information is key to successfully performing any analysis, and to helping technology developers or managers perform their jobs efficiently. Integrating information from all ELS elements and many interfacing systems or other programs is required to enable SIMA analysts to perform their own tasks, and SIMA's efforts can help other ELS elements and researchers as well. SIMA activities include developing and maintaining database tools to collect, distribute, and protect information on ELS projects, technologies. SIMA also provides a technology list to maintain a record of the many options available in life support systems, and generates a status report of new developments in the field from conference activity. Finally, as a product of the of analytical methods SIMA has developed and data that SIMA collects, results of integrated analyses can be used to demonstrate the achievements of the ELS Project and technology development.

Develop and apply analytical methods and tools needed to model, analyze, and evaluate life support options

SIMA uses a variety of analytical methods and simulation tools for the study of life support systems.

One key SIMA analysis method is the use of "Equivalent System Mass" (ESM) to compare the relative launch costs of options including not just the component or system mass, but also the cost of other vehicle systems that is due to the inclusion of that component or system. These impacts include the mass of pressure shells, power systems, cooling systems, and sometimes crewtime to operate or propulsion to move through various mission phases.

Simulations and modeling tools are implemented through a variety of methods to best suit the goals of the analysis. Detailed transient analysis is implemented in software that can support solving the complex sets of differential equations including mass and energy balances and chemical or physical properties, top-level steady-state simulations can be developed with a combination of programming and spreadsheet tools, and integrated tools combine key calculations in detailed software with database tools and spreadsheet analysis.