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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Solar simulation system requirements and design, comparing solar parameters with manned space center specifications for simulation
Beta emitting strontium 90 used as electron source for material testing in space environment simulation chamber
We introduce the open-source ExaWind modeling and simulation environment for wind energy. The primary physics codes of ExaWind are Nalu-Wind and OpenFAST. Nalu-Wind is a wind-focused computational fluid dynamics (CFD) code that is coupled to the whole-turbine simulation code OpenFAST. The ExaWind environment was created under U.S. Department of Energy funding to achieve the highest-fidelity simulations of wind turbines and wind farms to date, with the goal of enabling disruptive changes to turbine and plant design and operation. Innovation will be gleaned through better understanding of the complex flow dynamics in wind farms, including wake evolution and the impact of wakes on downstream turbines and turbulent flow from complex terrain. High-fidelity predictive simulations employ hybrid turbulence models, geometry/boundary-layer-resolving CFD meshes, atmospheric turbulence, nonlinear structural dynamics, and fluid-structure interaction. While there is an emphasis on very high-fidelity simulations (e.g., blade resolved with full fluid-structure coupling), the ExaWind environment supports lower-fidelity modeling capabilities including actuator-line and -disk methods. Important in the development of ExaWind codes is that the codes scale well on today's largest petascale supercomputers and on the next-generation platforms that will enable exascale computing.
Cryogenic fuels evaluated for operational safety in space environment simulation laboratory /SESL/
In the continued pursuit of creating a future with robust Urban Air Mobility (UAM) operations defined as safe and efficient air traffic operations in metropolitan environments for both piloted and autonomous systems, development of the concepts, technologies, and procedures to establish this UAM ecosystem remains an active area of research. In particular, as autonomous systems continue to grow in both complexity and use throughout UAM concepts the need for simulation environments to both test individual components and systems and to study the complex interactions between them is paramount. In this paper we address design considerations, technologies, and challenges of adapting native simulation environment application concepts to an interactive and distributed web-based framework. The proposed web-based design allows for easier and wider access for developing, testing, integrating, and studying emergent behaviors of complex autonomous systems interaction. We demonstrate the utility of the proposed approach by showing multi-agent interaction and emergent behavior in two scenarios: (1) autonomous urban air mobility vehicles flying in a convoy and (2) interaction of a convoy with a search and rescue operation.
Design, fabrication, and use of space magnetic environment simulation facility for spacecraft testing
A knowledge of the environmental conditions in space and an understanding of the possible effect on objects in that environment is necessary in order to make a full-scale, systematic exploration of outer space. Once these conditions have been determined, the understanding of the behavior of objects in space may be gained by simulating the environment in the laboratory and conducting experiments in the simulated environment. Among the conditions in space which have been determined and may be simulated are the pressure, the temperature, and the radiant energy. Quantitatively, simulating these conditions would require a pressure as low as 10 (exp -16) mm Hg, a sink temperature of approximately 30 to 40 K, and radiation similar to that from a 6,000 K black body. The features of the space environment directly affect the thermal balance of the spacecraft. The temperature of the object is that temperature which provides equilibrium between the energy absorbed by the object and the energy emitted by the object. Hence, a knowledge of the absorption and emission characteristics for materials under space environmental conditions must be obtained. High-speed particles may impact and erode the material surfaces and in that way alter the radiation properties of the materials and finally change the equilibrium temperature. Also, since most of the radiant energy (that from the sun) is from one direction, the-heat-transfer within the body will provide surface-temperature variations which depend upon the shape and orientation of the object and the properties of the material. These variations may be effectively studied in the simulated environment. Finally, because of the vacuum the heat transferred to and from the object must be accomplished solely by radiation. Thus, if heat-cycle power-generation equipment is to be used, the necessary rejection of heat must be accomplished by radiation from waste heat radiators whose design must be investigated in order to determine optimum configurations.
This paper presents the development of a generic component level model of a turbofan engine simulation with a digital controller, in an advanced graphical simulation environment. The goal of this effort is to develop and demonstrate a flexible simulation platform for future research in propulsion system control and diagnostic technology. A previously validated FORTRAN-based model of a modern, high-performance, military-type turbofan engine is being used to validate the platform development. The implementation process required the development of various innovative procedures, which are discussed in the paper. Open-loop and closed-loop comparisons are made between the two simulations. Future enhancements that are to be made to the modular engine simulation are summarized.
The lunar surface environment will present many challenges to the survivability of systems developed for long duration lunar habitation and exploration of the lunar, or any other planetary, surface. Obstacles will include issues pertaining especially to the radiation environment (solar plasma and electromagnetic radiation) and lunar regolith dust. The Planetary Environments Chamber is one piece of the MSFC capability in Space Environmental Effects Test and Analysis. Comprised of many unique test systems, MSFC has the most complete set of SEE test capabilities in one location allowing examination of combined space environmental effects without transporting already degraded, potentially fragile samples over long distances between tests. With this system, the individual and combined effects of the lunar radiation and regolith environment on materials, sub-systems, and small systems developed for the lunar return can be investigated. This combined environments facility represents a unique capability to NASA, in which tests can be tailored to any one aspect of the lunar environment (radiation, temperature, vacuum, regolith) or to several of them combined in a single test.
Lunar module reaction control system engine exhaust plume evaluation tests in space environment simulation laboratories
This paper presents progress on the development of a generic component level model of a turbofan engine simulation, with a digital controller, in an advanced graphical simulation environment. The goal of this effort is to develop and demonstrate a flexible simulation platform for future research in propulsion system control and diagnostic technology. A FORTRAN-based model of a modem, high performance, military-type turbofan engine is being used to validate the platform development. The implementation process required the development of various innovative procedures, which are discussed in the paper. Open-loop and closed-loop comparisons are made between the two simulations. Future enhancements that are to be made to the modular engine simulation are summarized.
This paper presents progress on the development of a generic component level model of a turbofan engine simulation, with a digital controller, in an advanced graphical simulation environment. The goal of this effort is to develop and demonstrate a flexible simulation platform for future research in propulsion system control and diagnostic technology. A FORTRAN-based model of a modern, high- performance, military-type turbofan engine is being used to validate the platform development. The implementation process required the development of various innovative procedures, which are discussed in the paper. Open-loop and closed-loop comparisons are made between the two simulations. Future enhancements that are to be made to the modular engine simulation are summarized.
Test methods for simulating hard radiation environment of optical telescopes in earth orbit
The final design for an effective Comet/Asteroid Protection System (CAPS) will likely come after a number of competing designs have been simulated and evaluated. Because of the large number of design parameters involved in a system capable of detecting an object, accurately determining its orbit, and diverting the impact threat, a comprehensive simulation environment will be an extremely valuable tool for the CAPS designers. A successful simulation/design tool will aid the user in identifying the critical parameters in the system and eventually allow for automatic optimization of the design once the relationships of the key parameters are understood. A CAPS configuration will consist of space-based detectors whose purpose is to scan the celestial sphere in search of objects likely to make a close approach to Earth and to determine with the greatest possible accuracy the orbits of those objects. Other components of a CAPS configuration may include systems for modifying the orbits of approaching objects, either for the purpose of preventing a collision or for positioning the object into an orbit where it can be studied or used as a mineral resource. The Synergistic Engineering Environment (SEE) is a space-systems design, evaluation, and visualization software tool being leveraged to simulate these aspects of the CAPS study. The long-term goal of the SEE is to provide capabilities to allow the user to build and compare various CAPS designs by running end-to-end simulations that encompass the scanning phase, the orbit determination phase, and the orbit modification phase of a given scenario. Herein, a brief description of the expected simulation phases is provided, the current status and available features of the SEE software system is reported, and examples are shown of how the system is used to build and evaluate a CAPS detection design. Conclusions and the roadmap for future development of the SEE are also presented.
The simulation of the thermal environment by varying the effective sink temperature about the test article was examined. The accuracy of this simulation depends upon the spectral emissivity/absorptivity, the number and size of the control zones, the temperature of each zone, and the geometry of the enclosure. A very large number of zones closely conforming to the surface of the test article quickly become prohibitive due to expense and control problems. A two zone low price enclosure does not have the fidelity required for thermal balance testing. The development of a simulator which for a reasonable cost, simulates the thermal balance environment for most large test articles in the future is described.
NASA’s Katherine Johnson Independent Verification and Validation (IV&V) Independent Test Capability (ITC) Team develops high fidelity software-only simulations (or “digital-twins”) of NASA’s most critical missions that are then used for software verification and validation (V&V). One such digital-twin simulator nearing maturity is the Psyche Hardware Abstraction Simulation Environment (PHASE). PHASE utilizes an instruction set simulator along with ITC-developed avionics models. PHASE includes a newly-developed model of the telecom hardware with a high-fidelity downlink interface, capable of supporting reconfigurable downlink data rates and transmission modes. The different downlink transmission modes allow more processing to be ceded from software onto the telecom hardware. Thus, we are able to monitor the performance of the downlink software module in the time-partitioned OS and perform more realistic dynamic testing based on software’s resource utilization. This presentation will cover PHASE, avionics modeling, the downlink model, and its usage for flight software performance testing.
Radioisotope measurement techniques and neutron activation analysis are evaluated for use in identifying and locating contamination sources in space environment simulation chambers. The alpha range method allows the determination of total contaminant concentration in vapor state and condensate state. A Cf-252 neutron activation analysis system for detecting oils and greases tagged with stable elements is described. While neutron activation analysis of tagged contaminants offers specificity, an on-site system is extremely costly to implement and provides only marginal detection sensitivity under even the most favorable conditions.
Upgrade of data acquisition and controls systems software at Johnson Space Center's Space Environment Simulation Laboratory (SESL) involved the definition, evaluation and selection of a system communication architecture and software components. A brief discussion of the background of the SESL and its data acquisition and controls systems provides a context for discussion of the requirements for each selection. Further framework is provided as upgrades to these systems accomplished in the 1990s and in 2003 are compared to demonstrate the role that technological advances have had in their improvement. Both of the selections were similar in their three phases; 1) definition of requirements, 2) identification of candidate products and their evaluation and testing and 3) selection by comparison of requirement fulfillment. The candidates for the communication architecture selection embraced several different methodologies which are explained and contrasted. Requirements for this selection are presented and the selection process is described. Several candidates for the software component of the data acquisition and controls system are identified, requirements for evaluation and selection are presented, and the evaluation process is described.