LM flight simulation in the space environment
Mission simulation testing in thermal vacuum environment for Apollo Lunar Module, noting conformal skin heaters
Ferrara, A. A.↗
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Evaluation of reformulated thermal control coatings in a simulated space environment. Part 1: YB-71
The Air Force Space and Missile Systems Center and Wright Laboratory Materials Directorate (WL/ML) have sponsored and effort to effort to reformulate and qualify Illinois Institute of Technology Research Institute (IITRI) spacecraft thermal control coatings. S13G/LO-1, Z93, and YB-71 coatings were reformulated because the potassium silicate binder, Sylvania PS-7, used in the coatings is no longer manufactured. Coatings utilizing the binder's replacement candidate, Kasil 2130, manufactured by The Philadelphia Quartz (PQ) Corporation, Baltimore, Maryland, and undergoing testing at the Materials Directorate's Space Combined Effects Primary Test and Research Equipment (SCEPTRE) Facility operated by the University of Dayton Research Institute (UDRI). The simulated space environment consists of combined ultraviolet (UV) and electron exposure with in site specimen reflectance measurements. A brief description of the effort at IITRI, results and discussion from testing the reformulated YB-71 coating in SCEPTRE, and plans for further testing of reformulated Z93 and S13G/LO-1 are presented.
Cerbus, Clifford A.↗
Durability of Solar Selective Coatings in a Simulated Space Environment
Solar selective coatings are being considered for heat engine and thermal switching applications on minisatellites. Such coatings must have the combined properties of high solar absorptance and low infrared emittance. High solar absorptance is needed to collect solar energy as efficiently as possible while low infrared emittance is needed to minimize radiant energy loss at operating temperature. These properties are achieved in sputter deposited thin films through the use of molecular mixtures of metal and dielectric. Solar selective coatings having a solar absorptance to infrared emittance ratio of 9 have been successfully deposited using a mixture of nickel and aluminum oxide. The space environment, however, presents some challenges for the use of materials on the exterior of spacecraft, including durability to atomic oxygen and vacuum ultraviolet radiation. To address these concerns, several candidate solar selective coatings were exposed to atomic oxygen in a plasma asher and to ultraviolet radiation in a vacuum facility equipped with calibrated deuterium lamps. The optical properties of the coatings were monitored as a function of time to evaluate their performance over long term exposure to the simulated space environment. Several coatings were found to be durable to both the atomic oxygen and the vacuum ultraviolet environments.
Jaworske, Donald A.↗
A study of Kapton degradation under simulated shuttle environment
A system was developed which employs a source of low energy oxygen ion to simulate the shuttle low Earth orbit environment. This source, together with diagnostic tools including surface analysis ans mass spectroscopic capability, was used to measure the dependence of ion energy of the oxygen induced CO signals from pyrolytic graphite and Kapton. For graphite the CO signal was examined at energies ranging form 4.5 to 465 eV and for Kapton from 4.5 to 188 eV. While the relative quantum yields inferred from the data are reasonably precise, there are large uncertainties in the absolute yields because of the assumptions necessary to covert the measured signal strengths to quantum yields. These assumptions are discussed in detail.
Eck, T. G.↗
Advancing Fissile Materials Production Modeling with Adaptive Computing Environment and Simulations (ACES)
The Department of Energy’s National Nuclear Security Administration (DOE/NNSA) provides advanced capabilities to simulate the uranium enrichment process to support international negotiations on the peaceful use of nuclear energy. Uranium isotope separation centrifuges connected in a cascade configuration can produce the low-enriched uranium needed for nuclear power. However, those same centrifuges connected in a different configuration can also produce highly enriched uranium for nuclear weapons. Having the capability to assess cascade operations and identify nefarious activities promotes the peaceful uses of nuclear energy while restricting nuclear weapons proliferation. DNN R&D's Nonproliferation Stewardship Program Adaptive Computing Environment and Simulations (ACES) project is creating a modern, sustainable ecosystem of physics-based models and data-analytics tools that enables analysts to model uranium enrichment systems, simulate operational scenarios, and apply various policy options to explore potential outcomes.
07 ISOTOPE AND RADIATION SOURCES↗
Optical Analysis of Transparent Polymeric Material Exposed to Simulated Space Environment
Many innovations in spacecraft power and propulsion have been recently tested at NASA, particularly in non-chemical propulsion. One improvement in solar array technology is solar concentration using thin polymer film Fresnel lenses. Weight and cost savings were proven with the Solar Concentrator Arrays with Refractive Linear Element Technology (SCARLET)-II array on NASA's Deep Space I spacecraft. The Fresnel lens concentrates solar energy onto high-efficiency solar cells, decreasing the area of solar cells needed for power. Continued efficiency of this power system relies on the thin film's durability in the space environment and maintaining transmission in the 300 - 1000 nm bandwidth. Various polymeric materials have been tested for use in solar concentrators, including Lexan(TM), polyethylene terephthalate (PET), several formulations of Tefzel(Tm) and Teflon(TM), and DC 93-500, the material selected for SCARLET-II. Also tested were several innovative materials including Langley Research Center's CPI and CP2 polymers and atomic oxygen- resistant polymers developed by Triton Systems, Inc. The Environmental Effects Group of the Marshall Space Flight Center's Materials, Processes, and Manufacturing Department exposed these materials to simulated space environment and evaluated them for any change in optical transmission. Samples were exposed to a minimum of 1000 equivalent Sun hours of near-UV radiation (250 - 400 nm wavelength). Materials that appeared robust after near-UV exposure were then exposed to charged particle radiation equivalent to a five-year dose in geosynchronous orbit. These exposures were performed in MSFC's Combined Environmental Effects Test Chamber, a unique facility with the capability to expose materials simultaneously or sequentially to protons, low-energy electrons, high-energy electrons, near UV radiation and vacuum UV radiation. Reflectance measurements can be made on the samples in vacuum. Prolonged exposure to the space environment will decrease the polymer film's transmission and thus reduce the conversion efficiency. A method was developed to normalize the transmission loss and thus rank the materials according to their tolerance to space environmental exposure. Spectral results and the material ranking according to transmission loss are presented.
Edwards, David L.↗
Performance of a 19.7 meter diameter disk gap band parachute in a simulated Martian environment
Inflation, and drag characteristics of disk gap band parachute in simulated low density Mars atmosphere
Bendura, R. J.↗
Performance of a 16.6-meter-diameter modified ringsail parachute in a simulated Martian environment
Inflation, drag, and stability characteristics of ringsail parachute deployed in simulated Mars atmosphere
Coltrane, L. C.↗
Survival of endospores of Bacillus subtilis on spacecraft surfaces under simulated martian environments: implications for the forward contamination of Mars
Experiments were conducted in a Mars simulation chamber (MSC) to characterize the survival of endospores of Bacillus subtilis under high UV irradiation and simulated martian conditions. The MSC was used to create Mars surface environments in which pressure (8.5 mb), temperature (-80, -40, -10, or +23 degrees C), gas composition (Earth-normal N2/O2 mix, pure N2, pure CO2, or a Mars gas mix), and UV-VIS-NIR fluence rates (200-1200 nm) were maintained within tight limits. The Mars gas mix was composed of CO2 (95.3%), N2 (2.7%), Ar (1.7%), O2 (0.2%), and water vapor (0.03%). Experiments were conducted to measure the effects of pressure, gas composition, and temperature alone or in combination with Mars-normal UV-VIS-NIR light environments. Endospores of B. subtilis, were deposited on aluminum coupons as monolayers in which the average density applied to coupons was 2.47 x 10(6) bacteria per sample. Populations of B. subtilis placed on aluminum coupons and subjected to an Earth-normal temperature (23 degrees C), pressure (1013 mb), and gas mix (normal N2/O2 ratio) but illuminated with a Mars-normal UV-VIS-NIR spectrum were reduced by over 99.9% after 30 sec exposure to Mars-normal UV fluence rates. However, it required at least 15 min of Mars-normal UV exposure to reduce bacterial populations on aluminum coupons to non-recoverable levels. These results were duplicated when bacteria were exposed to Mars-normal environments of temperature (-10 degrees C), pressure (8.5 mb), gas composition (pure CO2), and UV fluence rates. In other experiments, results indicated that the gas composition of the atmosphere and the temperature of the bacterial monolayers at the time of Mars UV exposure had no effects on the survival of bacterial endospores. But Mars-normal pressures (8.5 mb) were found to reduce survival by approximately 20-35% compared to Earth-normal pressures (1013 mb). The primary implications of these results are (a) that greater than 99.9% of bacterial populations on sun-exposed surfaces of spacecraft are likely to be inactivated within a few tens of seconds to a few minutes on the surface of Mars, and (b) that within a single Mars day under clear-sky conditions bacterial populations on sun-exposed surfaces of spacecraft will be sterilized. Furthermore, these results suggest that the high UV fluence rates on the martian surface can be an important resource in minimizing the forward contamination of Mars. c2003 Elsevier Inc. All rights reserved.
Bacillus subtilis/growth & development/physiology/↗
Control coordination in inverter‐based microgrids using AoI‐based 5G schedulers
Abstract A coordinated set point automatic adjustment with correction enabled (C‐SPAACE) framework that uses 5G communication for real‐time control coordination between inverter‐based resources (IBR) in microgrids is proposed. Utilising slicing capability, 5G offers low‐latency communication to C‐SPAACE under normal conditions. However, given the multitude of power grid use cases, a certain 5G slice for C‐SPAACE may have access only to limited radio spectrum resources, which if not managed well, greatly undermines the communication needs of C‐SPAACE framework. Thus, optimally scheduling the available spectrum resources among IBRs in a sliced 5G network‐based C‐SPAACE framework becomes a critical problem. To address this issue, the authors utilise a novel age of information (AoI) metric and designs an AoI‐based 5G scheduler to provide low‐latency communication to C‐SPAACE. Following this, a co‐simulation environment is designed using PSCAD/EMTDC and Python to simulate a microgrid supported by 5G communication. Time‐domain simulation case studies are performed using the proposed co‐simulation environment to evaluate the performance of C‐SPAACE using 5G with both AoI‐based and other baseline (non‐AoI) schedulers.
Choudhury, Biplav↗
Simulating Thermoelectric Devices Using the MOOSE Framework
Thermoelectric generators (TEG) are devices that generate energy by converting heat into electricity or provide cooling via the Peltier effect. This feature of thermoelectric devices originates from the Seebeck, Peltier, Thomson, and Joule heating effects. TEGs can be applied in energy and thermal management systems such as waste heat recovery and refrigeration, respectively. Thermoelectric device design is influenced by the material selection and the device's geometry operating conditions. Therefore, predicting, verifying, and validating thermoelectric device performance using simulations tools is essential to deploying thermoelectric devices in industry. The Multiphysics Object-Oriented Simulation Environment (MOOSE) Framework is an open-source simulation tool capable of modeling simple to complex systems. In this work, we demonstrate MOOSE's thermoelectric device modeling capabilities by simulating a unicouple, module, and exhaust gas recovery system. The Seebeck, Peltier, Thomson, and Joule heating physics are implemented into MOOSE. The MOOSE thermoelectric physics were thoroughly verified and validated using published COMSOL® results and experimental data. In addition, thermoelectric modules were integrated into an exhaust gas recovery system using the MOOSE MultiApp function as a demonstration of the model's ability. The verification and validation results and exhaust gas heat recovery system showcases MOOSE's capability to model thermoelectric devices and integrate these devices into practical energy systems.
42 - ENGINEERING↗
Simulating Humans as Integral Parts of Spacecraft Missions
The Collaborative-Virtual Environment Simulation Tool (C-VEST) software was developed for use in a NASA project entitled "3-D Interactive Digital Virtual Human." The project is oriented toward the use of a comprehensive suite of advanced software tools in computational simulations for the purposes of human-centered design of spacecraft missions and of the spacecraft, space suits, and other equipment to be used on the missions. The C-VEST software affords an unprecedented suite of capabilities for three-dimensional virtual-environment simulations with plug-in interfaces for physiological data, haptic interfaces, plug-and-play software, realtime control, and/or playback control. Mathematical models of the mechanics of the human body and of the aforementioned equipment are implemented in software and integrated to simulate forces exerted on and by astronauts as they work. The computational results can then support the iterative processes of design, building, and testing in applied systems engineering and integration. The results of the simulations provide guidance for devising measures to counteract effects of microgravity on the human body and for the rapid development of virtual (that is, simulated) prototypes of advanced space suits, cockpits, and robots to enhance the productivity, comfort, and safety of astronauts. The unique ability to implement human-in-the-loop immersion also makes the C-VEST software potentially valuable for use in commercial and academic settings beyond the original space-mission setting.
Bruins, Anthony C.↗
Multi-level Simulation of a Real Time Vibration Monitoring System Component
This paper describes the development of a custom built Digital Signal Processing (DSP) printed circuit board designed to implement the Advanced Real Time Vibration Monitoring Subsystem proposed by MSFC Transportation Directorate in 2000 for the Space Shuttle Main Engine Advanced Health Management System (AHMS). This Real Time Vibration Monitoring System (RTVMS) is being developed for ground use as part of the AHMS Health Management Computer-Integrated Rack Assembly (HMC-IRA). The HMC-IRA RTVMS design contains five DSPs which are highly interconnected through individual communication ports, shared memory, and a unique communication router that allows all the DSPs to receive digitized data from two multi-channel analog boards simultaneously. This paper will briefly cover the overall board design but will focus primarily on the state-of-the-art simulation environment within which this board was developed. This 16-layer board with over 1800 components and an additional mezzanine card has been an extremely challenging design. Utilization of a Mentor Graphics simulation environment provided the unique board and system level simulation capability to ascertain any timing or functional concerns before production. By combining VHDL, Synopsys Software and Hardware Models, and the Mentor Design Capture Environment, multiple simulations were developed to verify the RTVMS design. This multi-level simulation allowed the designers to achieve complete operability without error the first time the RTVMS printed circuit board was powered. The HMCIRA design has completed all engineering unit testing and the deliverable unit is currently under development.
Roberston, Bryan↗
Multi-level Simulation of a Real Time Vibration Monitoring System Component
This paper describes the development of a custom built Digital Signal Processing (DSP) printed circuit board designed to implement the Advanced Real Time Vibration Monitoring Subsystem proposed by Marshall Space Flight Center (MSFC) Transportation Directorate in 2000 for the Space Shuttle Main Engine Advanced Health Management System (AHMS). This Real Time Vibration Monitoring System (RTVMS) is being developed for ground use as part of the AHMS Health Management Computer-Integrated Rack Assembly (HMC-IRA). The HMC-IRA RTVMS design contains five DSPs which are highly interconnected through individual communication ports, shared memory, and a unique communication router that allows all the DSPs to receive digitized data fiom two multi-channel analog boards simultaneously. This paper will briefly cover the overall board design but will focus primarily on the state-of-the-art simulation environment within which this board was developed. This 16-layer board with over 1800 components and an additional mezzanine card has been an extremely challenging design. Utilization of a Mentor Graphics simulation environment provided the unique board and system level simulation capability to ascertain any timing or functional concerns before production. By combining VHDL, Synopsys Software and Hardware Models, and the Mentor Design Capture Environment, multiple simulations were developed to verify the RTVMS design. This multi-level simulation allowed the designers to achieve complete operability without error the first time the RTVMS printed circuit board was powered. The HMC-IRA design has completed all engineering and deliverable unit testing. P
Robertson, Bryan A.↗
A new coupling of a GPU-resident large-eddy simulation code with a multiphysics wind turbine simulation tool
The development of new wind farm control strategies can benefit from combined analysis of flow dynamics in the farm and the behavior of individual turbines within one simulation environment. In this work, we present such an environment by developing a new coupling between the large-eddy simulation (LES) code GRASP and the multiphysics wind turbine simulation tool OpenFAST via an actuator line model (ALM). In addition, the implementation of the recently proposed filtered actuator line model (FALM) within the coupling is described. The new ALM implementation is cross-verified with results from four other commonly used research LES codes. The results for the blade loads and the near wake obtained with the new coupling are consistent with the other codes. Deviations are observed in the far wake. The results further indicate that the FALM is able to reduce the lift and power overprediction from which the traditional ALM suffers on coarse LES grids. This new simulation environment paves the way for future wind farm simulations under realistic weather conditions by leveraging GRASP's ability to impose data from large-scale meteorological models as boundary conditions.
17 WIND ENERGY↗
Immersive Simulations and Engineering Environment (iSEE): Increasing the Realism of Simulations
The Immersive Simulations and Engineering Environment (iSEE) lab at Kennedy Space Center has been operating with its current team since 2017. The lab provides National Aeronautics and Space Administration (NASA) with simulations that show the stress and strain that a strenuous task can cause on a body. Previously the lab was using software that was efficient in ergonomic analysis of a human body, but limited in creating a realistic simulation. To produce a more realistic simulation, the iSEE invested in new software that could potentially create an environment that could show the viewer a simulation that was closer to reality.
Hodge, Brianna↗
Initial Integration of a Conflict Probabilities Service for Upper Class E Traffic Management
This paper outlines the development and integration of a conflict probability calculation-based service designed for Upper Class E Airspace operations. A key aspect of this effort is the integration of the conflict probability calculation algorithm into a simulated situational awareness client application. This application serves as a tool for flight operators to submit operations for Upper Class E Airspace within a simulated environment. The focus is on validating the effectiveness of the service through simulated intentional conflicting scenarios. The paper delves into the practicalities of integrating the conflict probability service into the user interface of the simulated situational awareness client application. This integration aims to enhance the decision-making capabilities of ETM operators within the simulated environment. The experiments and observations conducted in this simulated facility provide insights into the operational effectiveness of the proposed approach. In conclusion, this paper emphasizes the development, integration, and simulation-based validation of a conflict probability calculation service for Upper Class E Airspace. The findings underscore the potential impact of our approach on decision-making within a simulated setting, contributing to the understanding of its practical applications in operational scenarios.
Upper Class E Traffic Management↗
Simulated Excavation Environment for Lunar Operations
With new pushes to reach and establish long term presences on both the Moon and Mars, significant effort has begun to develop methods of In-Situ Resource Utilization. Many of these methods involve excavation and manipulation of local regolith and, at this time, many of these missions are in the early planning phases. As such, simulations provide both an inexpensive and relatively easy method to perform high level proofs of concept and mission overviews along with an environment to perform machine learning for rovers and other robots. The Simulated Excavation Environment for Lunar Operations (SEELO) was born out of this need for consolidated capabilities. SEELO seeks to provide accurate life mission environments and regolith interaction mechanics while remaining lightweight enough to run in faster than real-time. These combined features allow SEELO to be used for mission planning purposes that offer an environment for lunar robots to perform Machine Learning on moving, digging, and various other activities. Using the Real-Time Development Platform (Unity) to utilize regolith excavation models created by Intelligent Capabilities Enhanced-Regolith Advanced Surface Systems Operations Robot and lunar surface data collected by NASA’s Lunar Reconnaissance Orbiter, SEELO has been able to provide NASA with a tool to plan, train, and even devise lunar missions.
Michael DuPuis↗