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Cogeneration technology alternatives study. Volume 2: Industrial process characteristics

Information and data for 26 industrial processes are presented. The following information is given for each process: (1) a description of the process including the annual energy consumption and product production and plant capacity; (2) the energy requirements of the process for each unit of production and the detailed data concerning electrical energy requirements and also hot water, steam, and direct fired thermal requirements; (3) anticipated trends affecting energy requirements with new process or production technologies; and (4) representative plant data including capacity and projected requirements through the year 2000.

Source record↗

Development of Corrections for Biomass Burning Effects in Version 2 of GEWEX/SRB Algorithm

The objectives of this project were: (1) To incorporate into an existing version of the University of Maryland Surface Radiation Budget (SRB) model, optical parameters of forest fire aerosols, using best available information, as well as optical properties of other aerosols, identified as significant. (2) To run the model on regional scales with the new parametrization and information on forest fire occurrence and plume advection, as available from NASA LARC, and test improvements in inferring surface fluxes against daily values of measured fluxes. (3) Develop strategy how to incorporate the new parametrization on global scale and how to transfer modified model to NASA LARC.

Pinker, Rachel T.↗

The Direction of Fluid Dynamics for Liquid Propulsion at NASA Marshall Space Flight Center

Marshall Space Flight Center (MSFC) is the National Aeronautics and Space Administration (NASA)-designated center for the development of space launch systems. MSFC is particularly known for propulsion system development. Many engineering skills and technical disciplines are needed to accomplish this mission. This presentation will focus on the work of the Fluid Dynamics Branch (ER42). ER42 resides in the Propulsion Systems Department at MSFC. The branch is responsible for all aspects of the discipline of fluid dynamics applied to propulsion or propulsion-induced loads and environments. This work begins with design trades and parametric studies, and continues through development, risk assessment, anomaly investigation and resolution, and failure investigations. Applications include the propellant delivery system including the main propulsion system (MPS) and turbomachinery; combustion devices for liquid engines and solid rocket motors; coupled systems; and launch environments. An advantage of the branch is that it is neither analysis nor test centric, but discipline centric. Fluid dynamics assessments are made by analysis, from lumped parameter modeling through unsteady computational fluid dynamics (CFD); testing, which can be cold flow or hot fire; or a combination of analysis and testing. Integration of all discipline methods into one branch enables efficient and accurate support to the projects. To accomplish this work, the branch currently employs approximately fifty engineers divided into four teams -- Propellant Delivery CFD, Combustion Driven Flows CFD, Unsteady and Experimental Flows, and Acoustics and Stability. This discussion will highlight some of the work performed in the branch and the direction in which the branch is headed.

Griffin, Lisa W.↗

Python Based Plume Dynamics Estimation Tool (PyPDET) Rapid Plume Strike Analysis for RPOD Maneuvers in Deep Space Operations

I worked as a NASA Intern during the Summer 2023 term in the DS-00 division under the supervision of my mentor, Dr. Jonathan Pitt. Our goal was to build on our previous work from 2022 to develop a plume strike estimation tool using a prescribed physics methodology and model plume impingement effects while considering the dynamics of a rendezvous, operations, proximity, and docking (RPOD) maneuver. This tool supports previously configured CFD-DSMC calculations by allowing for rapid analysis of initial designs using a low-fidelity source flow model. Engineers can then use the high-fidelity CFD-DSMC tool to consolidate results as they work towards finalizing a design. This year’s project was focused on developing a software application that other engineers would be using in their analysis. Thus, the user’s experience was considered in the development of this application. Proper documentation, testability, and modularity of the codebase was our priority. For example, the project included auto documentation procedures to start building towards a User Manual, while also including dedicated demonstration cases for more explicit communication of functionality. Also, this project included a framework for testing the source code for future developments. Additionally, care was taken to develop the code using an Object-Oriented Programming approach. Thus, allowing for a modular extensibility of functionality in anticipation of future developments. The core work of this project was developing an algorithm that would transform the visiting vehicle and associated thruster data according to the kinematics described in the jet firing history. It would then calculate the estimated plume strikes on two of the target vehicles and write data accordingly into a VTK file. Summer work is to conclude by developing and presenting a PowerPoint slide deck at the intern exit briefing on August 11 th , 2023. Once the model for simple plume strike calculations is developed and tested there are several avenues to explore to continue development of this tool. These are also discussed in this report.

Plume Impingement↗

Risk Reduction Project in Pad Abort-1 Launch Vehicle Loads & Dynamics

The Pad Abort (PA-1) system includes the Launch Abort System (LAS) and the Command Module (CM). The PA-1 abort flight test will launch from the White Sands Missile Range. Prior to the ignition, the vehicle will be resting, without restraints, on a short support structure. The Launch Abort Motor will ignite and burn for less than 5 seconds before a 20 second coast. Then the LAS will separate from the CM and the CM will descend via parachute to a soil landing. The static firing of the Abort Motor (ST-1) for PA-1 Launch Vehicle resulted in unexpected higher levels that superseded the environment predictions and all the design and test loads of all subassemblies and components. A rapid project was put in place to develop the flight environments, loads and associated uncertainties for the Verification Load Cycle (VLC) of PA-1. An acoustic test and shaker test of the CM were planned and executed in support of the developments of damping and transfer functions. Instead of using the traditional structure-borne envelops, the actual ST-1 pressures and forces were used to develop the internal accelerations. The PA-1 motor was cooled to 60 Deg F using thermal conditioning to reduce the thrust profile. The plumes of the abort motor were studied to determine if the airborne environments would be reduced. The combination of all items, noted above, allowed a reduction in loads for VLC.

Sasan C Armand↗

Satellite-Based Evaluation of AeroCom Model Bias in Biomass Burning Regions

Global models are widely used to simulate biomass burning aerosol (BBA). Exhaustive evaluations on model representation of aerosol distributions and properties are fundamental to assess health and climate impacts of BBA. Here we conducted a comprehensive comparison of Aerosol Comparisons between Observations and Models (AeroCom) project model simulations with satellite observations. A total of 59 runs by 18 models from three AeroCom Phase-III experiments (i.e., biomass burning emissions, CTRL16, and CTRL19) and 14 satellite products of aerosols were used in the study. Aerosol optical depth (AOD) at 550 nm was investigated during the fire season over three key fire regions reflecting different fire dynamics (i.e., deforestation-dominated Amazon, Southern Hemisphere Africa where savannas are the key source of emissions, and boreal forest burning in boreal North America). The 14 satellite products were first evaluated against AErosol RObotic NETwork (AERONET) observations, with large uncertainties found. But these uncertainties had small impacts on the model evaluation that was dominated by modeling bias. Through a comparison with Polarization and Directionality of the Earth’s Reflectances measurements with the Generalized Retrieval of Aerosol and Surface Properties algorithm (POLDER-GRASP), we found that the modeled AOD values were biased by −93 % to 152 %, with most models showing significant underestimations even for the state-of-the-art aerosol modeling techniques (i.e., CTRL19). By scaling up BBA emissions, the negative biases in modeled AOD were significantly mitigated, although it yielded only negligible improvements in the correlation between models and observations, and the spatial and temporal variations in AOD biases did not change much. For models in CTRL16 and CTRL19, the large diversity in modeled AOD was in almost equal measures caused by diversity in emissions, lifetime, and the mass extinction coefficient (MEC). We found that in the AeroCom ensemble, BBA lifetime correlated significantly with particle deposition (as expected) and in turn correlated strongly with precipitation. Additional analysis based on Cloud-Aerosol LIdar with Orthogonal Polarization (CALIOP) aerosol profiles suggested that the altitude of the aerosol layer in the current models was generally too low, which also contributed to the bias in modeled lifetime. Modeled MECs exhibited significant correlations with the Ångström exponent (AE, an indicator of particle size). Comparisons with the POLDER-GRASP-observed AE suggested that the models tended to overestimate the AE (underestimated particle size), indicating a possible underestimation of MECs in models. The hygroscopic growth in most models generally agreed with observations and might not explain the overall underestimation of modeled AOD. Our results imply that current global models contain biases in important aerosol processes for BBA (e.g., emissions, removal, and optical properties) that remain to be addressed in future research.

biomass burning aerosols↗

Lewis Research Center's coal-fired, pressurized, fluidized-bed reactor test facility

A 200-kilowatt-thermal, pressurized, fluidized-bed (PFB) reactor, research test facility was designed, constructed, and operated as part of a NASA-funded project to assess and evaluate the effect of PFB hot-gas effluent on aircraft turbine engine materials that might have applications in stationary-power-plant turbogenerators. Some of the techniques and components developed for this PFB system are described. One of the more important items was the development of a two-in-one, gas-solids separator that removed 95+ percent of the solids in 1600 F to 1900 F gases. Another was a coal and sorbent feed and mixing system for injecting the fuel into the pressurized combustor. Also important were the controls and data-acquisition systems that enabled one person to operate the entire facility. The solid, liquid, and gas sub-systems all had problems that were solved over the 2-year operating time of the facility, which culminated in a 400-hour, hot-gas, turbine test.

Kobak, J. A.↗

ERBE and AVHRR Cirrus cloud fire study

Understanding the impact of cirrus clouds on the global radiation budget is essential to determining the role of clouds in the process of climate change. The ongoing Earth Radiation Budget Experiment (ERBE) is charged with measuring the global radiation balance at the top of the atmosphere. The International Satellite Cloud Climatology Project (ISCCP) is measuring global cloud amounts and properties over a time frame similar to ERBE. Specific cloud properties are absent from the ERBE program, while ISCCP lacks the broadband radiances necessary to determine the total radiation fields. Together, results from these two global programs have the potential for improving the knowledge of the relationship between cirrus clouds and the Earth radiation balance. The First ISCCP Regional Experiment (FIRE), especially its cirrus Intensive Field Observations (IFO), provides opportunities for studying radiation measurements from the ERBE taken over areas with known cirrus cloud properties. Satellite measurements taken during the IFO are used to determine the broadband radiation fields over cirrus clouds and to examine the relationship between narrowband and broadband radiances over various known scenes. The latter constitutes the link between the ERBE and the ISCCP.

Harrison, Edwin F.↗

Cloud fraction, layer, and direction of movement results from sky cameras during the FIRE IFO, Coffeyville, Kansas, experiment for the period Nov. 12 through Dec. 9, 1991

Tables and figures are presented which show local site observations of cloud fractions, the number of cloud layers, direction of movement, and precipitation data collected during the FIRE (First ISCCP Regional Experiment) Phase 2 Cirrus Intensive Field Observations (IFO) conducted in Coffeyville, Kansas during November and December, 1991. Selected data are also presented at the times of the TIROS Operational Vertical Sounder (TOVS) satellite overpass. Several major scientific projects have used surface-based observations of clouds to compare directly with those being observed from satellites. Characterizing the physical properties of clouds is extremely useful in obtaining a more accurate analysis of the effect of clouds and their movements on weather and climate. It is the purpose of this paper to report data collected during the FIRE Phase 2 IFO experiment and to provide a brief history of such a surface-based system and the technical information required for recording local cloud parameters.

Gerald C Purgold↗

Use of Taguchi design of experiments to optimize and increase robustness of preliminary designs

The research performed this summer includes the completion of work begun last summer in support of the Air Launched Personnel Launch System parametric study, providing support on the development of the test matrices for the plume experiments in the Plume Model Investigation Team Project, and aiding in the conceptual design of a lunar habitat. After the conclusion of last years Summer Program, the Systems Definition Branch continued with the Air Launched Personnel Launch System (ALPLS) study by running three experiments defined by L27 Orthogonal Arrays. Although the data was evaluated during the academic year, the analysis of variance and the final project review were completed this summer. The Plume Model Investigation Team (PLUMMIT) was formed by the Engineering Directorate to develop a consensus position on plume impingement loads and to validate plume flowfield models. In order to obtain a large number of individual correlated data sets for model validation, a series of plume experiments was planned. A preliminary 'full factorial' test matrix indicated that 73,024 jet firings would be necessary to obtain all of the information requested. As this was approximately 100 times more firings than the scheduled use of Vacuum Chamber A would permit, considerable effort was needed to reduce the test matrix and optimize it with respect to the specific objectives of the program. Part of the First Lunar Outpost Project deals with Lunar Habitat. Requirements for the habitat include radiation protection, a safe haven for occasional solar flare storms, an airlock module as well as consumables to support 34 extra vehicular activities during a 45 day mission. The objective for the proposed work was to collaborate with the Habitat Team on the development and reusability of the Logistics Modules.

Carrasco, Hector R.↗

Vibration Isolation Technology (VIT) ATD Project

A fundamental advantage for performing material processing and fluid physics experiments in an orbital environment is the reduction in gravity driven phenomena. However, experience with manned spacecraft such as the Space Transportation System (STS) has demonstrated a dynamic acceleration environment far from being characterized as a 'microgravity' platform. Vibrations and transient disturbances from crew motions, thruster firings, rotating machinery etc. can have detrimental effects on many proposed microgravity science experiments. These same disturbances are also to be expected on the future space station. The Microgravity Science and Applications Division (MSAD) of the Office of Life and Microgravity Sciences and Applications (OLMSA), NASA Headquarters recognized the need for addressing this fundamental issue. As a result an Advanced Technology Development (ATD) project was initiated in the area of Vibration Isolation Technology (VIT) to develop methodologies for meeting future microgravity science needs. The objective of the Vibration Isolation Technology ATD project was to provide technology for the isolation of microgravity science experiments by developing methods to maintain a predictable, well defined, well characterized, and reproducible low-gravity environment, consistent with the needs of the microgravity science community. Included implicitly in this objective was the goal of advising the science community and hardware developers of the fundamental need to address the importance of maintaining, and how to maintain, a microgravity environment. This document will summarize the accomplishments of the VIT ATD which is now completed. There were three specific thrusts involved in the ATD effort. An analytical effort was performed at the Marshall Space Flight Center to define the sensitivity of selected experiments to residual and dynamic accelerations. This effort was redirected about half way through the ATD focusing specifically on the sensitivity of protein crystals to a realistic orbital environment. The other two thrusts of the ATD were performed at the Lewis Research Center. The first was to develop technology in the area of reactionless mechanisms and robotics to support the eventual development of robotics for servicing microgravity science experiments. This activity was completed in 1990. The second was to develop vibration isolation and damping technology providing protection for sensitive science experiments. In conjunction with the this activity, two workshops were held. The results of these were summarized and are included in this report.

Lubomski, Joseph F.↗

Integrating Remote Sensing Observations with NASA's GEOS-5 Modeling Framework in Support of Retrospective Analyses and Seasonal Prediction of Biosphere-Atmosphere CO2 Flux

The absorption of nearly half of all anthropogenic carbon dioxide (CO2) emissions by terrestrial and marine ecosystems has played a critical role in mitigating climate change. However, a persistent lack of understanding of these uptake processes impedes attribution, and thereby introduces large uncertainties into projections of the trajectory of carbon and climate in coming decades. A better understanding and quantification of the seasonal and interannual variability of carbon flux between the atmosphere and ocean and terrestrial biospheres is critically needed to improve predictions from Earth system models. We propose to bring together a diverse suite of remote sensing observations, mechanistic models, and NASA's Goddard Earth Observing System, version 5 (GEOS-5) model to address two objective 1) quantify the processes controlling the temporal variability of biosphere-atmosphere CO2 flux on seasonal and interannual timescales from 1989 to 2018 and 2) evaluating the predictability of the components of carbon flux on seasonal timescales. Because GEOS-5 has been developed to incorporate a variety of Earth system observations and includes a complete and physically consistent depiction of the atmosphere, land, and ocean carbon cycles, it represents a unique and ideal synthesis framework for this effort. By expanding the realism of processes that could be included in GEOS-5 seasonal forecasts, this effort supports NASA's goals toward an integrated Earth system modeling and prediction framework.We propose to integrate a number of observations into the GEOS-5 modeling system to refine retrospective estimates of both terrestrial and marine carbon flux and to test hypotheses regarding the effects of climate drivers on terrestrial carbon flux. This will include assimilating several satellite ocean color products in the NASA Ocean Biogeochemistry Model (NOBM) to improve the representation of ocean biology. We will also utilize remote sensing datasets to increase the temporal resolution of global land-use change estimates and fire emissions to better constrain the temporal variability of the terrestrial carbon cycle. This information will be incorporated into two NASA terrestrial biosphere models Catchment-CN, a dynamic vegetation model that is integrated within GEOS-5 and the Ecosystem Demography (ED) model, a core modeling resource supporting the Global Ecosystem Dynamics Investigation (GEDI) mission to map biomass. Fluxes will be evaluated through 1) comparison to top-down flux estimates inferred from surface CO2 observations and 2) comparison against available aircraft and satellite observations.By combining predictions of net ecosystem exchange and air-sea CO2 flux from land and ocean models with statistical predictions of land use change, fire, and fossil fuel emissions, we propose to create the first dynamical CO2 forecast on seasonal timescales. Because of the experimental nature of this endeavor, an important project objective will be to evaluate the limits to the predictability of different carbon cycle processes over lead times of 1-12 months using different satellite and surface data streams.

Ott, Lesley↗

Effect of pressure on a burning solid in low-gravity

Venting, or depressurization, has been discussed as a possible technique for extinguishing fires on aircraft and spacecraft. Fire suppression plans for the International Space Station Alpha (ISSA) discuss the use of depressurization as a method for extinguishing fires. In the case of an uncontrollable fire, the affected compartment would be vented from an initial pressure of 1.0 atm (14.7 psia) to a final pressure 0.33 atm (4.8 psia) within 10 minutes. However, the lack of low pressure flammability data for solid materials in a low-gravity environment presents an uncertainty for the use of the venting technique. There are also transient effects that need to be considered. It is possible that the flows induced by the venting could intensify the fire. This occurred during flammability tests conducted on board Skylab. In addition, the extinction pressure could be a function of the depressurization rate. Studies conducted with solid propellants have shown that if the pressure is reduced quickly enough, the pressure at extinction will be greater than the steady-state extinction limit. This project, which was started in 1992, is examining both the quasi steady-state and transient effects of pressure reduction on a burning solid in low-gravity. This research will provide low-g extinguishment data upon which policies and practices can be formulated for fire safety in orbiting spacecraft.

Goldmeer, Jeffrey S.↗

The experiments of LIPS 3

LIPS 3 is a member of the Living Plume Shield series of spacecraft. In each LIPS project, the plume shield, a simple sheet metal cone, was structurally stiffened, and an active satellite was then built around it. The original purpose of the plume shield was to prevent the plume from solid propellent engines, which are fired outside the atmosphere after the aerodynamic shroud is jettisoned, from reaching the primary payload. The surface of LIPS 3 facing the plume also functioned in this manner, but the anterior surfaces were unaffected, and it was there that all solar arrays, sensors, and experiments were mounted. The purpose of LIPS 3 was to provide a test bed for new space power sources. With the long delays projected for schedules of the STS and other major launch systems, it appeared that a decade might pass before long term flight data could be obtained on many new and innovative power sources. The fact that a launch scheduled for early in 1987 required a plume shield was seen as a unique opportunity to obtain some of this data in a timely manner. The LIPS 3 system, the experiments placed aboard, and the experiment data acquisition subsystem are described. Various problems were encountered during integration and after launch; those which appear to effect the accuracy of experimental results are discussed. A preliminary description is given of the accuracy of the flight experiment data.

Severns, J. G.↗

Global biomass burning - Atmospheric, climatic, and biospheric implications

The present volume discusses the biomass burning (BMB) studies of the International Global Atmospheric Chemistry project, GEO satellite estimation of Amazonian BMB, remote sensing of BMB in West Africa with NOAA-AVHRR, an orbital view of the great Chinese fire of 1987, BMB's role in tropical rainforest reduction, CO and O3 measurements of BMB in the Amazon, effects of vegetation burning on the atmospheric chemistry of the Venezuelan savanna, an assessment of annually-burned biomass in Africa, and light hydrocarbon emissions from African savanna burnings. Also discussed are BMB in India, trace gas and particulate emissions from BMB in temperate ecosystems, ammonia and nitric acid emissions from wetlands and boreal forest fires, combustion emissions and satellite imagery of BMB, BMB in the perspective of the global carbon cycle, modeling trace-gas emissions from BMB, NO(x) emissions from BMB, and cloud-condensation nuclei from BMB.

Levine, Joel S.↗

An Experimental and Theoretical Study of Radiative Extinction of Diffusion Flames

In a recent paper on 'Observations of candle flames under various atmospheres in microgravity' by Ross et al., it was found that for the same atmosphere, the burning rate per unit wick surface area and the flame temperature were considerably reduced in microgravity as compared with normal gravity. Also, the flame (spherical in microgravity) was much thicker and further removed from the wick. It thus appears that the flame becomes 'weaker' in microgravity due to the absence of buoyancy generated flow which serves to transport the oxidizer to the combustion zone and remove the hot combustion products from it. The buoyant flow, which may be characterized by the strain rate, assists the diffusion process to execute these essential functions for the survival of the flame. Thus, the diffusion flame is 'weak' at very low strain rates and as the strain rate increases the flame is initially 'strengthened' and eventually it may be 'blown out'. The computed flammability boundaries of T'ien show that such a reversal in material flammability occurs at strain rates around 5 sec. At very low or zero strain rates, flame radiation is expected to considerably affect this 'weak' diffusion flame because: (1) the concentration of combustion products which participate in gas radiation is high in the flame zone; and (2) low strain rates provide sufficient residence time for substantial amounts of soot to form which is usually responsible for a major portion of the radiative heat loss. We anticipate that flame radiation will eventually extinguish this flame. Thus, the objective of this project is to perform an experimental and theoretical investigation of radiation-induced extinction of diffusion flames under microgravity conditions. This is important for spacecraft fire safety.

Atreya, Arvind↗

CryoCart Restoration and Vacuum Pipe Construction

Propulsion systems that utilize hypergolic propellants have been used to power space vehicles since the beginning of the space program. Liquid methane and oxygen propulsion systems have emerged as an alternative and have proven to be more environmentally friendly. The incorporation of liquid methane/liquid oxygen (LOX) into the propulsion system has demonstrated an increase in engine performance, as well as a reduction in the volume, size and complexity of the system. Consequently, reducing the total mass of the vehicle which is a crucial aspect that is considered when planning space missions to both the Moon and Mars [1]. Project Morpheus has made significant advancements in liquid oxygen/liquid methane propulsion system technologies by incorporating a LOX/methane propulsion system to a vertical test bed. The vehicle consisted of a 5,000 lb main engine and four 20 lb remote control system (RCS) engines that utilize liquid methane/LOX as its propellant [1]. The vehicle completed successful flight testing at Kennedy Space Center in 2014 which marked the completion of the Morpheus project. Subsequent projects utilizing Morpheus' vertical test bed have been developed to make further advancements. One of the subsequent projects consisted of the addition of a smaller 2,000 lb main engine and a cold helium heat exchanger which would make it possible for a pressurant tank systems to be send to Mars or the Moon by significantly decreasing the overall mass and volume of the pressurant tank. The hot fire tests of the integrated system with the smaller main engine and cold helium heat exchanger were successful at sea level, but further studies are being conducted to better understand how the vertical test bed will behave under thermal-vacuum conditions. For this reason, the integrated vehicle will be taken to Plum Brook to be tested in a chamber capable of simulating these conditions. To ensure that the vehicle will function properly under vacuum conditions, testing will be first completed at the component level. During this process, the igniter of the main engine and the RCS thrusters will be tested under a vacuum. To complete the testing of the components, the test setup first needed to be finalized. The CryoCart is being used to feed the propellants to the test article. The CryoCart is a movable test set-up that was developed in 2009 to provide a mobile platform for testing oxygen/methane systems with hot-fire capability up to 100 lbf. The CryoCart consists of three different systems: Oxygen, Methane, and liquid Nitrogen. The Oxygen and Methane systems are placed into two different carts while the liquid nitrogen system is mainly located in the methane cart. Over the years, the CryoCart has been utilized for different projects and has undergone deterioration. For this reason, a new phase has been developed to rebuild it to working conditions once again. During my internship, I was aiding in the construction and restoration of the CryoCart. In the initial stages of the process, I updated the fluid and electrical schematics for the oxygen, methane, and test article systems. The original CryoCart consisted of an electrical panel that utilized electromechanical relays and a terminal to drive the igniter power and signal, as well as the main fuel and oxygen valves. This electrical panel connected to the CryoCart through various wire harnesses that could be found exiting from the CryoCart. First, it was determined how these harnesses connected to the electromechanical relays so that they worked correctly. Once the electrical system was understood, an alternative for the electromechanical relays and the Molex connectors used throughout the system was sought since these components can often prove to be unreliable. Solid State relays and MIL connectors were purchased to serve as replacements. Upon arrival of the parts, crimping and wiring was completed to install the new solid state relays and MIL connectors. During the replacement of the relays and connectors, system checks of the electrical system were ran to ensure that the system was working correctly. While completing system checks, the pressure transducers that were not functioning properly were also replaced and any issue with the wiring or signal was addressed. Once the electrical components were replaced, the restoration of the fluid system began. Parts of the tubing in the CryoCart had to be rebuild and often consisted of sizing, cutting, bending, filing, and sanding the tubing to prepare it to be flared. Many components had to be proof-tested to bring their certifications up to date, and several components had to be replaced. Various flex hoses, valves, and fittings were send to the Clean Lab because they were new, dirty, or had gone through proof-testing. Once they arrived from the cleaning lab they had to be put back to the system and leak checks and functional tests were conducted. In the Nitrogen system, the copper tubing located in the Oxygen cart was rebuild and Aerogel insulation was added to this section. A new gaseous nitrogen system was added to the CryoCart to purge the vacuum tube which will serve as the test chamber. Once the CryoCart was completed, construction of parts of the vacuum tube began. A flange was manufactured with welded fittings to hold the line of the vacuum pump as well as some extra fittings which will serve as extra inlets used to introduce fluid lines to the vacuum tube. Stress analysis was ran in this flange to ensure that it would not fail under vacuum conditions. The fluid lines leading from the air side of the vacuum to the test article were also constructed and added to the mount that had already been manufactured. Three different sets of tubing were constructed to accommodate the seven different RCS thruster and the main engine igniter that are going to be tested. Full electrical system checks were completed to ensure that all the wire harnesses and valves were functioning. Upon the completion of the CryoCart and the vacuum tube, hot fire testing for the RCS thrusters and the main engine igniter are going to begin. During this time any issues encountered with the engines or igniter will be addressed to ensure that the components function under vacuum conditions. After successful completion of testing, the vertical test bed, Morpheus, will be rebuilt and prepared to be sent to Plum Brook. In Plum Brook, the vehicle will be tested in the thermal-vacuum chamber to demonstrate that integrated lox-methane propulsion system operation in space-like conditions. This internship has allowed me the opportunity to gain valuable hands on experience and to develop skills that will aid in my education as well as in the workforce, while at the same time helping me determine that I would like to further pursue a career in propulsion engineering.

Chaidez, Mariana↗

Regolith Simulant Preparation and Geotechnical Characterization for Plume Surface Interaction Testing

Descent engine plumes interact with the lunar surface and accelerate regolith particles to potentially high velocities. These ejecta create risks to surface assets that have yet to be fully assessed. To better understand these risks, plume surface interactions can be simulated on the ground by firing a test engine plume into a bin of lunar regolith simulant under vacuum conditions. The dynamics of the resultant ejecta can then be recorded. In this technical memorandum we discuss the processes used in preparing a 150 kg bin of lunar regolith simulant for plume surface interaction ground tests under vacuum conditions for the NASA STMD Plume Surface Interaction project. We present our approach to mitigating regolith simulant eruptions during pump-down, the methods used to fill and reset the regolith simulant bin for each test, and the techniques used to characterize the consistency of regolith simulant geotechnical properties before each new firing. The challenges of preparing a regolith simulant test bin below an ambient pressure of one atmosphere, particularly on the large scale, could largely be overcome with a system that could fill the test bin with simulant inside the chamber and under vacuum conditions.

lunar regolith↗