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Ames Technology Capabilities and Facilities

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Multi-Fidelity Vehicle Modeling and Simulation
 

An integrated set of tools of various disciplines and fidelity levels which enable rapid analysis of a broad range of scenarios for risk mitigation.

Benefit
Decent and landing analysis Elements of this multi-fidelity modeling and simulation capability were exercised in critical analysis efforts for the Space Launch Initiative including:

  • Integrated Stack Ascent and Separation Analysis
  • Vehicle Aerodynamics, Heating, and Re-Entry Analysis
  • Pad Abort Demonstrator (Crew Escape) Aerodynamics
  • OSP Aerodynamic Design Optimization
  • OSP/EELV Ascent, Abort, and Recovery Analysis
  • Aerodynamics, Structures, Heating, Re-entry and Abort Analyses

Right: Descent and landing analysis

Research Overview
An integrated multi-fidelity, multi-disciplinary software framework for mission analysis and system design has been developed and is being enhanced, primarily for application to design for enhanced crew safety though broader application. A modular software system, allowing straightforward integration of new analyses tools in various disciplines and of various levels of cost/fidelity and development of persistent composite analysis types, would provide a powerful tool for: 1) performing multi-disciplinary analyses at various design phases, 2) reducing risks associated with sole reliance on either engineering or hi-fidelity methods, 3) developing requirements for hi-fidelity analyses and experimental testing, and 4) retaining knowledge of experienced users of the analysis tools.

The resulting system will be capable of multi-disciplinary analyses such as concurrent aerodynamic/six-degree-of-freedom abort separation analysis with vehicle structural response, as well as coupled analyses involving a single discipline at multiple fidelity levels such as error/uncertainty estimation and database generation using fused data from multiple analysis tools. An integrated, risk-driven design analysis capability has been put into practice, using the NASA High End Computing resources, to provide high fidelity, multi-disciplinary data in support of design trade space analysis and decision-making for safe vehicle design. In 2003, using a model of a Crew Transfer Vehicle/Orbital Space Plane on a reusable launch system, the simulation demonstrated multi-fidelity aerodynamics and structural analyses for ascent and time-accurate abort separation simulation, trajectory optimization, and entry, descent and landing aerodynamics, heating and controllability analysis. This multi-disciplinary capability will provide a foundation for the modeling, design and analysis of integrated launch systems in nominal and failure modes. New vehicle designs can be analyzed through large numbers of simulation conditions to enable the updating of legacy probabilistic risk assessment (PRA) data with statistically significant failure prediction rates. Continued integration development will also enable the performance of integrated system health monitoring (ISHM) simulations to determine the relative values of proposed monitoring, failure alert, and mitigation capabilities throughout the ascent and entry flight regimes.

Continuing Development Includes:
Aerodynamics demonstration
Analysis of complex geometries for crew escape, coupled with orbiter and launch vehicle. Work will primarily focus on separation dynamics, resulting stability characteristics, and re-entry and recovery issues.

Population of a probabilistic risk assessment failure prediction database with statistical data derived from many high fidelity computations, coupled with intelligent data fusion and augmentation techniques.

The application of high fidelity simulations to the investigation of ISHM technologies, coupling monitoring and warning characteristics of proposed technologies with high fidelity computation, results to determine efficacy of proposed approaches.

Right: Aerodynamics demonstrated in simulated ascent.

Background
A critical requirement in support of the Exploration Initiative will be the development of robust, reliable, safe vehicles that assure crew safety and mission success. The ability to provide integrated, multi-disciplinary analyses of vehicles and launch systems throughout the mission is critical to success in this endeavor. Vehicle and architecture analyses and technology trade studies will be required to generate and validate requirements, develop designs for robust, reliable, crew-safe vehicles for Space Exploration. This requires integrated, multi-fidelity tools for: 1) rapid modeling and design of space vehicle concepts, and 2) providing high confidence analysis of vehicle and crew risk, and of risk mitigation strategies and technologies. This integrated vehicle modeling and mission simulation capability will enable rapid, high confidence failure modeling, vehicle risk analysis, and analysis of fault mitigation technologies. Vehicle design assessmentA risk-based design process, utilizing simulation generated risk assessments and risk-driven survival analysis will be critical to the development of the next generations of space vehicles. Ames is continuing the development of a capability for integrating risk assessment and mission simulation. With the ability to simulate vehicle abort and subsequent vehicle recovery analysis, the next steps must be to generate fully integrated simulation and risk assessment for continued updates of risk database and mission performance and technology assessments.

Caption: Vehicle design assessment.