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NASA NTRS2002

Technology Assessments within NASA's Integrated Technology Assessment Center

NASA's Advanced Space Transportation Program (ASTP) founded the Integrated Technology Assessment Center (ITAC) to provide a comprehensive, systematic approach to identify long-term technology needs, to quantify payoffs for technology investments, and to assess the progress of ASTP-sponsored technology programs in the hypersonics/Earth-to-orbit area. To accomplish these goals, the ITAC has assembled an experienced team representing a broad sector of the aerospace community and developed a systematic assessment process complete with supporting tools. In the ITAC approach, concepts for transportation systems are first selected based on relevance to the ASTP. Models of these concepts are then developed and data on advanced technologies are collected. Projections of key technology characteristics with respect to the specific concepts of interest are made. Both the models and technology projections are then fed into the ITAC's probabilistic systems analysis framework. The probabilistic outputs are weighed against metrics of interest to ASTP and a multivariate decision making process is used to provide inputs for technology prioritization within the ASTP. At present, the ITAC program is working to evaluate a variety of technologies for three two-stage hypersonic vehicle concepts. Concepts include an all rocket, vertical take off-horizontal landing (VTHL) system, a horizontal takeoff-horizontal landing (HTHL) RBCC-propelled first stage/all rocket second stage system, and an HTHL turbine-based first stage/all rocket second stage system. This paper will provide a status update of the ITAC program including current results and plans.

Taylor, J. L.↗

NASA NTRS2002

Integrated Technology Assessment Center (ITAC) Update

The Integrated Technology Assessment Center (ITAC) has developed a flexible systems analysis framework to identify long-term technology needs, quantify payoffs for technology investments, and assess the progress of ASTP-sponsored technology programs in the hypersonics area. For this, ITAC has assembled an experienced team representing a broad sector of the aerospace community and developed a systematic assessment process complete with supporting tools. Concepts for transportation systems are selected based on relevance to the ASTP and integrated concept models (ICM) of these concepts are developed. Key technologies of interest are identified and projections are made of their characteristics with respect to their impacts on key aspects of the specific concepts of interest. Both the models and technology projections are then fed into the ITAC's probabilistic systems analysis framework in ModelCenter. This framework permits rapid sensitivity analysis, single point design assessment, and a full probabilistic assessment of each concept with respect to both embedded and enhancing technologies. Probabilistic outputs are weighed against metrics of interest to ASTP using a multivariate decision making process to provide inputs for technology prioritization within the ASTP. ITAC program is currently finishing the assessment of a two-stage-to-orbit (TSTO), rocket-based combined cycle (RBCC) concept and a TSTO turbine-based combined cycle (TBCC) concept developed by the team with inputs from NASA. A baseline all rocket TSTO concept is also being developed for comparison. Boeing has recently submitted a performance model for their Flexible Aerospace System Solution for Tomorrow (FASST) concept and the ISAT program will provide inputs for a single-stage-to-orbit (SSTO) TBCC based concept in the near-term. Both of these latter concepts will be analyzed within the ITAC framework over the summer. This paper provides a status update of the ITAC program.

Taylor, J. L.↗

NASA NTRS2003

Combustion Devices CFD Simulation Capability Roadmap

The objective of this roadmap is to enable the use of CFD for simulation of pre-burners, ducting, thrust chamber assembly and supporting infrastructure in terms of performance, life, and stability so as to affect the design process in a timely fashion. To enable flange to exit analysis of real(3D) propulsion hardware within the last 5 years (2008). To meet this objective all model problems must be sufficiently mastered.

West, Jeff↗

NASA NTRS2007

Developing the Parachute System for NASA's Orion: An Overview at Inception

As the Crew Exploration Vehicle (CEV) program developed, NASA decided to provide the parachute portion of the landing system as Government Furnished Equipment (GFE) and designated NASA Johnson Space Center (JSC) as the responsible NASA center based on JSC s past experience with the X-38 program. JSC subsequently chose to have the Engineering Support contractor Jacobs Sverdrup to manage the overall program development. After a detailed source selection process Jacobs chose Irvin Aerospace Inc (Irvin) to provide the parachutes and mortars for the CEV Parachute Assembly System (CPAS). Thus the CPAS development team, including JSC, Jacobs and Irvin has been formed. While development flight testing will have just begun at the time this paper is submitted, a number of significant design decisions relative to the architecture for the manned spacecraft will have been completed. This paper will present an overview of the approach CPAS is taking to providing the parachute system for CEV, including: system requirements, the preliminary design solution, and the planned/completed flight testing.

Machin, Ricardo↗

NASA NTRS2007

Robust Low-Cost Cathode for Commercial Applications

Under funding from the NASA Commercial Technology Office, a cathode assembly was designed, developed, fabricated, and tested for use in plasma sources for ground-based materials processing applications. The cathode development activity relied on the large prior NASA investment and successful development of high-current, high-efficiency, long-life hollow cathodes for use on the International Space Station Plasma Contactor System. The hollow cathode was designed and fabricated based on known engineering criteria and manufacturing processes for compatibility with the requirements of the plasma source. The transfer of NASA GRC-developed hollow cathode technology for use as an electron emitter in the commercial plasma source is anticipated to yield a significant increase in process control, while eliminating the present issues of electron emitter lifetime and contamination.

Patterson, Michael J.↗

NASA NTRS2005

Controlling Force and Depth in Friction Stir Welding

Feedback control of the penetration force applied to a pin tool in friction stir welding has been found to be a robust and reliable means for controlling the depth of penetration of the tool. This discovery has made it possible to simplify depth control and to weld with greater repeatability, even on workpieces with long weld joints. Prior to this discovery, depths of penetration in friction stir welding were controlled by hard-tooled roller assemblies or by depth actuators controlled by feedback from such external sensors as linear variable-differential transformers or laser-based devices. These means of control are limited: A hard-tooled roller assembly confines a pin tool to a preset depth that cannot be changed easily during the welding process. A measurement by an external sensor is only an indirect indicative of the depth of penetration, and computations to correlate such a measurement with a depth of penetration are vulnerable to error. The present force-feedback approach exploits the proportionality between the depth and the force of penetration Unlike a depth measurement taken by an external sensor, a force measurement can be direct because it can be taken by a sensor coupled directly to the pin tool. The reading can be processed through a modern electronic servo control system to control an actuator to keep the applied penetration force at the desired level. In comparison with the older depth-control methods described above, this method offers greater sensitivity to plasticizing of the workpiece metal and is less sensitive to process noise, resulting in a more consistent process. In an experiment, a tapered panel was friction stir welded while controlling the force of penetration according to this method. The figure is a plot of measurements taken during the experiment, showing that force was controlled with a variation of 200 lb (890 N), resulting in control of the depth of penetration with a variation of 0.004 in. (0.1 mm).

Adams, Glynn↗

NASA NTRS2012

Issues and Design Drivers for Deep Space Habitats

A cross-disciplinary team of scientists and engineers applied expertise gained in Lunar Lander development to the conceptual design of a long-duration, deep space habitat for Near Earth Asteroid (NEA) missions. The design reference mission involved two launches to assemble 5-modules for a 380-day round trip mission carrying 4 crew members. The conceptual design process yielded a number of interesting debates, some of which could be significant design drivers in a detailed Deep Space Habitat (DSH) design. These issues included: Design to minimize crew radiation exposure, launch loads, communications challenges, docking system and hatch commonality, pointing and visibility, consumables, and design for contingency operations.

Rucker, Michelle A.↗

NASA NTRSDate not supplied

Analysis of the cost, schedule, and risk for Lynx mirror assembly production

This paper analyzes a recently published model for Lynx Mirror Assembly production duration, to understand the sensitivity of duration to various factors. The factors considered are finite process yield, knowledge of the individual process times and finite server reliability. In all of these cases, closed form estimates are given along with numerical examples. This initial analysis indicates that accurate and precise knowledge of the process times is fundamental to making an accurate prediction of schedule duration. Analysis of the failure of any given server is also explained and can be used as the basis of a rational sparing policy.

Jonathan W. Arenberg↗

NASA NTRSDate not supplied

Colloids in Microgravity

Colloidal particles are important in a broad range of applications in technology and materials processing. Due to high sensitivity to thermal fluctuations, a suspension of colloidal particles is considered as an assembly of super-atoms in condensed matter physics. This feature provides an excellent experimental model in statistical mechanics for fundamental studies of microstructural evolution and phase transformation at the individual particle level. However, using colloids to probe three-dimensional phase transitions on Earth remains a challenge as they can be influenced by the gravity force causing the particles to sediment and the solvent to flow. To suppress the undesirable gravity effects, experiments on concentrated colloids were carried out in the International Space Station (ISS) Light Microscopy Module. We will present results of these experiments.

Colloids↗

NASA NTRS1991

Systems engineering studies of on-orbit assembly operation

While the practice of construction has a long history, the underlying theory of construction is relatively young. Very little has been documented as to techniques of logistic support, construction planning, construction scheduling, construction testing, and inspection. The lack of 'systems approaches' to construction processes is certainly one of the most serious roadblocks to the construction of space structures. System engineering research efforts at CSC are aimed at developing concepts and tools which contribute to a systems theory of space construction. The research is also aimed at providing means for trade-offs of design parameters for other research areas in CSC. Systems engineering activity at CSC has divided space construction into the areas of orbital assembly, lunar base construction, interplanetary transport vehicle construction, and Mars base construction. A brief summary of recent results is given. Several models for 'launch-on-time' were developed. Launch-on-time is a critical concept to the assembly of such Earth-orbiting structures as the Space Station Freedom, and to planetary orbiters such as the Mars transfer vehicle. CSC has developed a launch vehicle selection model which uses linear programming to find optimal combinations of launch vehicles of various sizes (Atlas, Titan, Shuttles, HLLV's) to support SEI missions. Recently, the Center developed a cost trade-off model for studying on orbit assembly logistics. With this model it was determined that the most effective size of the HLLV would be in the range of 120 to 200 metric tons to LEO, which is consistent with the choices of General Stafford's Synthesis Group Report. A second-generation Dynamic Construction Activities Model ('DYCAM') process model has been under development, based on our past results in interruptability and our initial DYCAM model. This second-generation model is built on the paradigm of knowledge-based expert systems. It is aimed at providing answers to two questions: (1) what are some necessary or sufficient conditions for judging conceptual designs of spacecraft?, and (2) can a methodology be formulated such that these conditions may be used to provide computer-aided tools for evaluating conceptual designs and planning for space assembly sequences? Early simulation results indicate that the DYCAM model has a clear ability to emulate and simulate human orbital construction processes.

Morgenthaler, George W.↗

DOE OSTI2025

Two decades of bacterial ecology and evolution in a freshwater lake

Ecology and evolution are considered distinct processes that interact on contemporary time scales in microbiomes. Here, to observe these processes in a natural system, we collected a two-decade, 471-metagenome time series from Lake Mendota (Wisconsin, USA). We assembled 2,855 species-representative genomes and found that genomic change was common and frequent. By tracking strain composition via single nucleotide variants, we identified cyclical seasonal patterns in 80% and decadal shifts in 20% of species. In the dominant freshwater family Nanopelagicaceae, environmental extremes coincided with shifts in strain composition and positive selection of amino acid and nucleic acid metabolism genes. Further, these genes identify organic nitrogen compounds as potential drivers of freshwater responses to global change. Seasonal and long-term strain dynamics could be regarded as ecological processes or, equivalently, as evolutionary change. Rather than as distinct interacting processes, we propose a conceptualization of ecology and evolution as a continuum to better describe change in microbial communities.

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRS1991

Thermal verification testing of commercial printed-circuit boards for spaceflight

A method is discussed developed to verify commercial printed-circuit boards for a shuttle orbital flight. The Space Acceleration Measurement System Project used this method first with great success. The test sequence is based on early fault detection, desire to test the final assembly, and integration with other verification testing. A component thermal screening test is performed first to force flaws in design, workmanship, parts, processes, and materials into observable failures. Then temperature definition tests are performed that consist of infrared scanning, thermal vacuum testing, and preliminary thermal operational testing. Only the engineering unit is used for temperature definition testing, but the preliminary thermal operational testing is performed on the flight unit after the temperature range has been defined. In the sequence of testing, vibration testing is performed next, but most vibration failures cannot be detected without subsequent temperature cycling. Finally, final assembly testing is performed to simulate the shuttle flight. An abbreviated thermal screening test is performed as a check after the vibration test, and then a complete thermal operational test is performed. The final assembly test finishes up with a burn-in of 100 hours of trouble-free operation. Verification is successful when all components and final assemblies have passed each test satisfactory. This method was very successful in verifying that commercial printed-circuit boards will survive in the shuttle environment.

Foster, William M., II↗

DOE OSTI2020

Hydrogen Transport in a Model 9979 Shipping Package with Inner Convenience Cans

Radiolytic hydrogen production and accumulation inside containment packages is a concern at any facility responsible for their packaging, storage, transportation, and/or disposal. When hydrogen gas accumulates to concentrations above the Lower Flammability Limit (LFL) which is 4% or 40,000 ppm in air, the possibility of a deflagration or explosion increases. This concern persists over the course of the package lifetime which is unlimited when disposed of by burial or in permanent repositories. Here, we report on a numerical model used to predict the concentration of hydrogen within each layer of a Model 9979 package containing a convenience can assembly. Simulations show the hydrogen concentration to always be highest in the inner convenience can containing the radioactive source. When the radioactive source is within the Los Alamos National Laboratory (LANL) Packaging Limits, the hydrogen concentration is shown to remain well below the LFL at all times including packaging, storage, transportation, and disposal. A hydrogen transport model is presented for a Model 9979 package system containing a nested arrangement of convenience cans, which are tin oxide coated steel cans of various sizes with a slip-lid assembly. The inner convenience can contains the radioactive source material along with an unknown quantity of incidental water acquired from humid air or processing. While visible organic materials such as paper and plastics were purposely excluded from the inner can, it is not possible to claim the wastes are entirely organic free. The inner convenience can is tape sealed and placed into a plastic bag which is horsetail closed (i.e., twisted and taped). The bagged can is placed into an outer convenience can that is also tape sealed. The can assembly is then placed into the 30 gallon drum and subsequently placed inside the 55 gallon drum in the 9979 package. Here we assume hydrogen gas is produced in the inner convenience can from alpha radiolysis of water at a rate dependent on the quantity of uranium isotopes and water present. The hydrogen transport model was used to calculate hydrogen accumulations within the package’s five layers at different times and conditions. These simulations serve two purposes; (i) to build confidence in the model by comparing predicted values to measured values, and (ii) to check the steady state hydrogen concentrations that are approached at long times in the package’s lifetime. Model simulations were compared to gas samples taken from the 30 gallon drum after storage at LANL’s Chemistry and Metallurgy Research (CMR) building for around 500 days. Hydrogen concentration calculations over much longer periods (i.e., more than 270 years) included extreme storage durations, transportation at extreme cold temperatures, and disposal of packages assuming different average temperatures.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2024

A Simulated Evaluation of Powder Flowability Through a Partially Obstructed Consumable in Blown Powder Directed Energy Deposition Systems

Abstract In the interest of continued industrialization of metal additive manufacturing in modern production environments, cost is often referenced as a primary deterrent to new adopters. Conventional economic models for additive systems, processes, and supply chains often focus on specific process applications with little generalizability, or they neglect significant costs associated with production such as machine maintenance and consumable part replacement. Compounding the latter issue are substantial knowledge gaps in consumable part wear characterization for additive and other convergent manufacturing systems. In coaxial blown powder directed energy deposition systems, gas atomized metal powder is wasted during material deposition at a rate that is partly dependent on present wear phenomena in a consumable nozzle housed in the cladding head assembly. The price and lead time required to replace the nozzle incentivizes its reuse even when visibly worn. Often this initiates a process quality decline in the form of underbuilt geometry and internal defects due to losses in powder catchment efficiency. While depositing H13 steel using a hybrid manufacturing machine tool equipped with such a deposition system, a unique partial clog with a bridge-like structure formed at the consumable nozzle exit when supporting argon gas flows failed mid-process. To further understand coaxial multi-phase powder flow in the event of support gas failure, a computational fluid dynamics simulation is tailored to relevant process parameters, H13 powder material profile, and machine operator observations collected after the incident. The resulting differences in powder flow compared to control gas flow parameters is presented and discussed. The powder flowability and performance of the clogged nozzle is then assessed by using an optical profilometer to extract the profile of the clog and recreate the clog geometry within the simulation environment. In past work this simulation has been experimentally validated for a 316L steel powder material profile and used specifically for analyzing powder stream geometry and catchment efficiency. After the initial powder flow characterization, the clog is removed, and the nozzle is reprofiled. After removing the obstructing clog, the newly unobstructed nozzle geometry, the original off the shelf nozzle geometry, and additional nozzle profiles exploring different consumable refurbishment strategies are reevaluated in the simulation. Powder catchment efficiency for all variant nozzle geometries and relevant flow variables are compared and discussed, along with potential mitigation strategies for optimizing powder flowability with worn consumables. This work expands on the known morphology of blown powder obstructions and wear defects present in consumable coaxial nozzles while discussing pragmatic simulation driven responses to unanticipated subsystem failure in hybrid manufacturing machining platforms.

DeWitte, Lisa↗

DOE OSTI2022

Development and Performance Evaluation of of Active Insulation Systems using Solid-State Thermal Switches

Traditional building envelopes have passive insulation systems that cannot respond to dynamic changes in the environment. An Active Insulation System (AIS) consists of Active Insulation Materials (AIMs), which dynamically vary the thermal conductivity of the insulation system. Several researchers have evaluated the impact of AIS on building thermal and energy performance by using simulation tools. Up to 70% savings in annual heating and cooling energy and significant reductions in peak demand have been predicted for some climates with wall systems employing AIS. Sensitivity studies have provided requirements for the AIS properties and control schemes that can lead to those savings. However, materials and assembly development have not yet achieved a cost-effective product that achieves the required performance. In this study, we present the process to develop an AIS that we will install in a test hut for their performance evaluation. Minimum performance criteria of the AIS system are developed based on Rmin/Rmax ratio, required time and efficiency to switch states and cost estimate. The next step carried out during this study is creating the concept to meet the requirements, predicting the performance by simulations, developing the experimental setup for bench-scale testing, and finally, constructing a full-scale wall assembly and monitoring the performance when exposed to natural weather conditions. The selected approach uses off-the-shelf products to create a materials system that can switch R-value between R~=1 ft2·°F·h/BTU (0.18 m2·K/W) and R~=7 ft2·°F·h/BTU (1.23 m2·K/W and have a switching time of less than one minute between R-high and R-low.

Iffa, Emishaw↗

NASA NTRS2014

Data Albums: An Event Driven Search, Aggregation and Curation Tool for Earth Science

One of the largest continuing challenges in any Earth science investigation is the discovery and access of useful science content from the increasingly large volumes of Earth science data and related information available. Approaches used in Earth science research such as case study analysis and climatology studies involve gathering discovering and gathering diverse data sets and information to support the research goals. Research based on case studies involves a detailed description of specific weather events using data from different sources, to characterize physical processes in play for a specific event. Climatology-based research tends to focus on the representativeness of a given event, by studying the characteristics and distribution of a large number of events. This allows researchers to generalize characteristics such as spatio-temporal distribution, intensity, annual cycle, duration, etc. To gather relevant data and information for case studies and climatology analysis is both tedious and time consuming. Current Earth science data systems are designed with the assumption that researchers access data primarily by instrument or geophysical parameter. Those who know exactly the datasets of interest can obtain the specific files they need using these systems. However, in cases where researchers are interested in studying a significant event, they have to manually assemble a variety of datasets relevant to it by searching the different distributed data systems. In these cases, a search process needs to be organized around the event rather than observing instruments. In addition, the existing data systems assume users have sufficient knowledge regarding the domain vocabulary to be able to effectively utilize their catalogs. These systems do not support new or interdisciplinary researchers who may be unfamiliar with the domain terminology. This paper presents a specialized search, aggregation and curation tool for Earth science to address these existing challenges. The search tool automatically creates curated "Data Albums", aggregated collections of information related to a specific science topic or event, containing links to relevant data files (granules) from different instruments; tools and services for visualization and analysis; and information about the event contained in news reports, images or videos to supplement research analysis. Curation in the tool is driven via an ontology based relevancy ranking algorithm to filter out non-relevant information and data.

Ramachandran, Rahul↗

DOE OSTI2020

The ABC130 barrel module prototyping programme for the ATLAS strip tracker

For the Phase-II Upgrade of the ATLAS Detector [1], its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100% silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon sensor modules in the central region (barrel) and 7,000 modules in the forward region (end-caps), which are foreseen to be constructed over a period of 3.5 years. The construction of each module consists of a series of assembly and quality control steps, which were engineered to be identical for all production sites. In order to develop the tooling and procedures for assembly and testing of these modules, two series of major prototyping programs were conducted: an early program using readout chips designed using a 250 nm fabrication process (ABCN-250) [2,2] and a subsequent program using a follow-up chip set made using 130 nm processing (ABC130 and HCC130 chips). This second generation of readout chips was used for an extensive prototyping program that produced around 100 barrel-type modules and contributed significantly to the development of the final module layout. This paper gives an overview of the components used in ABC130 barrel modules, their assembly procedure and findings resulting from their tests.

47 OTHER INSTRUMENTATION↗

DOE OSTI2022

Rotational Dynamics and Transition Mechanisms of Surface-Adsorbed Proteins

Assembly of biomolecules at solid-water interfaces requires molecules to traverse complex orientation-dependent energy landscapes through processes that are poorly understood, largely due to the dearth of in-situ single molecule measurements and statistical analyses of the rotational dynamics that define directional selection. Emerging capabilities in high-speed atomic force microscopy and machine learning have allowed us to directly determine the orientational energy landscape and observe and quantify the rotational dynamics for protein nanorods on the surface of muscovite mica under a variety of conditions. Comparisons with kinetic Monte Carlo simulations show that the transition rates between adjacent orientation-specific energetic minima can largely be understood through traditional models of in-plane Brownian rotation across a biased energy landscape, with resulting transition rates that are exponential in the energy-barriers between states. However, transitions between more distant angular states are decoupled from barrier height, with jump-size distributions showing a power-law decay that is characteristic of a non-classical Levy-flight random walk, indicating that large jumps are enabled by alternative modes of motion via activated states. The findings provide new insights into the dynamics of biomolecules at solid-liquid interfaces that lead to self-assembly, epitaxial matching and other orientationally anisotropic outcomes and define a general procedure for exploring such dynamics with implications for hybrid biomolecular-inorganic materials design.

Orientational energy landscapes, Rotational dynami↗