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NASA NTRS2001

ALEXIS Observations of the Monogem Ring Supernova Remnant

The subject grant is for the analysis of ALEXIS observations of the Monogem Ring supernova remnant using the diffuse all-sky maps produced from the ALEXIS all-sky survey. The work is to produce ratio maps of the three energy bands provided by ALEXIS, analyze the ratio data to constrain the intervening neutral hydrogen column density and the temperature and elemental abundances of the X-ray emitting gas, compare the structure to that observed in the ROSAT maps, and incorporate the results into current supenova remnant evolution models. The work outlined above has been significantly delayed since the ALEXIS diffuse all-sky maps took longer to produce than anticipated. Unfortunately, the ALEXIS satellite suffered a failure of the Pegasus launch vehicle which left the satellite in a partially functioning condition. The attitude control system of the spacecraft was unable to operate as planned and this has greatly increased the complexity of the aspect solution. Our colleagues at Los Alamos have made progress in producing these maps and are nearing completion of the final maps. However, the quality of the data have been significantly compromised by the overall lower exposure due to the spacecraft problems and the higher background of the micro-channel plate detectors. We have compared the ALEXIS and ROSAT maps of this region of the sky and there is no obvious signal in the ALEXIS maps of the Monogem Ring. We are now exploring correlation techniques to determine if there is indeed a faint signal in the ALEXIS maps. Although, the project has been a disappointment so far, the data may still provide a valuable lower limit on the neutral hydrogen column density. This is a far cry from our original intentions, but would still be valuable science. Given the large delays in producing the ALEXIS sky maps, this work will continue past the end of the grant period.

Plucinsky, Paul↗

NASA NTRS1994

Reduction of parasitic lasing

A technique was developed which carefully retro-reflects precisely controlled amounts of light back into a laser system thereby intentionally forcing the laser system components to oscillate in a new resonator called the parasitic oscillator. The parasitic oscillator uses the laser system to provide the gain and an external mirror is used to provide the output coupling of the new resonator. Any change of gain or loss inside the new resonator will directly change the lasing threshold of the parasitic oscillator. This change in threshold can be experimentally measured as a change in the absolute value of reflectivity, provided by the external mirror, necessary to achieve lasing in the parasitic oscillator. Discrepancies between experimental data and a parasitic oscillator model are direct evidence of optical misalignment or component performance problems. Any changes in the optical system can instantly be measured as a change in threshold for the parasitic oscillator. This technique also enables aligning the system for maximum parasitic suppression with the system fully operational.

Storm, Mark E.↗

NASA NTRS2017

Work Term Assignment Spring 2017

My tour in the Engineering Robotics directorate exceeded my expectations. I learned lessons about Creo, manufacturing and assembly, collaboration, and troubleshooting. During my first tour, last spring, I used Creo on a smaller project, but had limited experience with it before starting in the Dynamic Systems Test branch this spring. I gained valuable experience learning assembly design, sheet metal design and designing with intent for manufacturing and assembly. These skills came from working both on the hatch and the floor. I also learned to understand the intent of other designers on models I worked with. While redesigning the floor, I was modifying an existing part and worked to understand what the previous designer had done to make it fit with the new model. Through working with the machine shop and in the mock-up, I learned much more about manufacturing and assembly. I used a Dremel, rivet gun, belt sander, and countersink for the first time. Through taking multiple safety training for different machine shops, I learned new machine shop safety skills specific to each one. This semester also gave me new collaborative opportunities. I collaborated with engineers within my branch as well as with Human Factors and the building 10 machine shop. This experience helped me learn how to design for functionality and assembly, not only for what would be easiest in my designs. In addition to these experiences, I learned many lessons in troubleshooting. I was the first person in my office to use a Windows 10 computer. This caused unexpected issues with NASA services and programs, such as the Digital Data Management Server (DDMS). Because of this, I gained experience finding solutions to lockout and freeze issues as well as Creo specific settings. These will be useful skills to have in the future and will be implemented in future rotations. This co-op tour has motivated me more to finish my degree and pursue my academic goals. I intend to take a machining Career Gateway Elective in the Fall to improve my skills in building as well as designing with manufacturing intent. I am also inspired to take more mechatronics CGE courses before I graduate to learn more about the crossover between mechanical and electrical engineering. This semester, I worked on multiple projects and had the opportunity to learn from engineers of different disciplines. I became proficient in Creo 2.0, a program I had not used significantly before. I finished modifying the hatch for 3D print and made sizeable modifications to the nose floor support design. I also gained hands-on experience that will be useful in my engineering career in the future. I would consider all of these major achievements from this spring semester. Lastly, I learned to ask more questions and to search for the right people to find answers which I know will be a valuable skill in the future. This summer, I will be completing my last rotation in the Flight Operations Directorate at Ellington Air Field. After this last tour, I will be returning to school for the Fall, Spring and Summer. I will graduate in August of 2018. I am looking forward to learning more about the different jobs available to engineers. This division works directly with many different types of aircrafts and I am excited to learn more about this focus of engineering. The Aircraft Operations Division values team work greatly and I intend to improve my interpersonal skills by working with them this summer.

Sico, Mallory↗

NASA NTRS2012

Portable Fourier Transform Spectroscopy for Analysis of Surface Contamination and Quality Control

Progress has been made into adapting and enhancing a commercially available infrared spectrometer for the development of a handheld device for in-field measurements of the chemical composition of various samples of materials. The intent is to duplicate the functionality of a benchtop Fourier transform infrared spectrometer (FTIR) within the compactness of a handheld instrument with significantly improved spectral responsivity. Existing commercial technology, like the deuterated L-alanine triglycine sulfide detectors (DLATGS), is capable of sensitive in-field chemical analysis. This proposed approach compares several subsystem elements of the FTIR inside of the commercial, non-benchtop system to the commercial benchtop systems. These subsystem elements are the detector, the preamplifier and associated electronics of the detector, the interferometer, associated readout parameters, and cooling. This effort will examine these different detector subsystem elements to look for limitations in each. These limitations will be explored collaboratively with the commercial provider, and will be prioritized to meet the deliverable objectives. The tool design will be that of a handheld gun containing the IR filament source and associated optics. It will operate in a point-and-shoot manner, pointing the source and optics at the sample under test and capturing the reflected response of the material in the same handheld gun. Data will be captured via the gun and ported to a laptop.

Pugel, Diane↗

NASA NTRSDate not supplied

A Survey of Autonomous Navigation Techniques Applicable to Lunar Surface Exploration

As humanity returns to the Moon, and more and more attention is being paid to lunar surface operations, there is a greater need than ever for methods of surface navigation. These could be methods of computer-assisted orienteering for astronauts exploring on foot during an Extra-Vehicular Activity (EVA), or methods of solving the Lost-on-the-Moon problem to initialize a crewed or autonomous rover’s state estimate. It may also be necessary to process navigation data associated with surface samples or other surface operations a posteriori to better understand where that analysis occurred. Autonomous rover operation will also require Hazard Detection and Avoidance (HDA) and terrain-aware pathfinding. While navigation on the surface of the Moon will likely rely on Earth-based assets such as the Deep Space Network (DSN) or communication with other spacecraft (e.g., LunaNet, LCRNS, pre-deployed moon beacons, a nearby lander) it may be necessary to navigate in a loss-of-communication scenario. This paper analyzes the methods of surface navigation used on other celestial bodies, such as those used during the Apollo missions and autonomous exploration of Mars, as well as novel methods which have been studied but not yet implemented which may prove useful. It is shown that the navigator has myriad options when processing data from an Inertial Measurement Unit (IMU), a star tracker, (rover) wheel encoders, optical cameras, and LIght Detection and Ranging (LIDAR) sensors. The intention of this paper is to provide a broad overview of what has been done and what could be done, to aid those designing vehicles and/or missions to the lunar surface.

Paul D Mckee↗

NASA NTRSDate not supplied

A Survey of Autonomous Navigation Techniques Applicable to Lunar Surface Exploration

Paul McKee↗

DOE OSTI2026

Deep Learning enabled spectral energy conversion for in situ exposure measurements

A detector-specific deep learning (DL) approach is presented for spectra-to-exposure conversion using large-format sodium iodide (NaI(Tl)) detectors deployed for in situ environmental radiation measurements in emergency response scenarios. Accurate determination of exposure from NaI spectra is challenging due to poor energy resolution, partial energy absorption, and the strong sensitivity of traditionally deployed analytical conversion methods to calibrated source geometry and pre-deployment assumptions. Here, to address these limitations, a multi-layer perceptron model was trained on a hybrid in situ /Monte Carlo dataset constructed to span a broad range of photon energies, spatial extents, and realistic deployment variability, representative of general in situ emergency response conditions. The DL model was evaluated against commonly fielded analytical approaches under matched simulation conditions, including a single-factor method, a G-function method, and a modeled pressurized ion chamber (PIC) baseline. This study was intentionally computational in scope to enable controlled, like-for-like comparisons between conversion techniques while minimizing confounding real-world variability. Comparison to the modeled PIC provides contextual benchmarking and is not intended as a field inter-comparison with deployed instruments. Across the evaluated 20 keV to 3 MeV energy range, the DL approach consistently exhibited higher accuracy and reduced variance relative to the analytical methods against a deterministically calculated exposure. This may indicate improved robustness to spectral complexity without reliance on source-, geometric-, or spectral region-specific optimization. While results do not represent real-world validation, the presented work demonstrates that deep learning may effectively learn the nonlinear detector response-to-exposure relationship for asymmetric NaI(Tl) detectors and offers a promising pathway for improving in situ exposure estimation using spectroscopic systems already integrated into initial real-time emergency response operations.

61 RADIATION PROTECTION AND DOSIMETRY↗

DOE OSTI2021

Correlation between Sensor Performance, Autonomy Performance and Fuel-Efficiency in Semi-Truck Platoons

Semi-trucks, specifically class-8 trucks, have recently become a platform of interest for autonomy systems. Platooning involves multiple trucks following each n close proximity, with only the lead truck being manually driven and the rest being controlled autonomously. This approach to semi-truck autonomy is easily integrated on existing platforms, reduces delivery times, and reduces green- house gas emissions via fuel economy benefits. Level 1 SAE fuel studies were performed on class-8 trucks operating with the Auburn Cooperative Adaptive Cruise Control (CACC) system, and fuel savings up to 10-12% were seen. Enabling platooning autonomy required the use of radar, global positioning systems (GPS), and wireless vehicle-to-vehicle (V2V) communication. Poor measurements and state estimates can lead to incorrect or missing positioning data, which can lead to unnecessary dynamics and finally wasted fuel. This is especially an issue if deceleration is applied in response to a bad measurement. In this study, a faulty radar was shown to cause a greater than 5% increase in fuel consumption. The mechanism of this fuel consumption increase is investigated and applied to other types of sensor failures to indicate their potential effects on fuel economy. This analysis indicates that poor GPS signals over short time can be largely filtered out, with no real gain or loss of fuel economy. V2V communications were intentionally limited by causing interference, which resulted in dropped communication packets over a small physical area, but not an appreciable impact on fuel economy.

vehicle platooning, sensor performance, semi-auton↗

DOE OSTI2023

Mechanistic modeling of copper corrosions in data center environments

Air-side economizers are increasingly used to take advantage of “free-cooling” in data centers with the intent of reducing the carbon footprint of buildings. However, they can introduce outdoor pollutants to indoor environment of data centers and cause corrosion damage to the information technology equipment. Here, to evaluate the reliability of information technology equipment under various thermal and air-pollution conditions, a mechanistic model based on multi-ion transport and chemical reactions was developed. The model was used to predict Cu corrosion caused by Cl2-containing pollutant mixtures. It also accounted for the effects of temperature (25 °C and 28 °C), relative humidity (50%, 75%, and 95%), and synergism. It also identified higher air temperature as a corrosion barrier and higher relative humidity as a corrosion accelerator, which agreed well with the experimental results. The average root mean square error of the prediction was 13.7 Å. The model can be used to evaluate the thermal guideline for data centers design and operation when Cl2 is present based on pre-established acceptable risk of corrosion in data centers’ environment.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Carbon Dioxide Utilization for Plasma Nanosynthesis of Carbon

This DOE Phase I SBIR project has developed a glow discharge-based plasma process to convert carbon dioxide to sold carbon and water. By adding natural gas, the additional enthalpy can be used to reform the output carbon dioxide to value added carbon and EPA-compliance-grade water, thus creating a process that has no gaseous products at all, such as: CO 2 + CH 4 → 2C + 2H 2 O, which is simply the exothermic reverse of the syngas reaction. During the Phase I work, several milestones were accomplished successfully. a. First, a synthesis reactor was designed, assembled, and successfully operated using the combined simultaneous operation of glow discharge and microwaves. DC discharge and microwaves can also be operated individually, allowing multiple configurations to be used This is one of the first reactors of its kind, and perhaps the first ever. b. Second, the research team successfully produced carbon nanomaterials using carbon dioxide as the source of carbon via CO 2 + 2H 2 → C + 2H 2 O. This is certainly one of the first processes to use plasma to convert carbon dioxide to nanocarbon, and perhaps the first ever demonstration. c. Third, it was also shown that carbon monoxide and carbon dioxide can be used with methane to reduce the synthesis temperature of ASI graphene decorated carbon nanotubes (GDCNT). Hitherto GDCNT were only fabricated above 1200 °C. GDCNT was synthesized at 780 °C. CO 2 + C → 2CO; 2 CO + CH 4 → 3 C + 2H 2 O, and also, CH 4 + CO 2 → 2 C + 2H 2 O. d. Fourth, closed cycle synthesis of nanomaterial was demonstrated with over 80% conversion of carbon dioxide to carbon and water was achieved, on the basis of pressure drop during glow discharge. e. Fifth, plasma operation was achieved via glow discharge and microwaves at 500 Torr, demonstrating a path forward to atmospheric pressure operation f. Sixth, using carbon monoxide and carbon dioxide in an electrothermal furnace, we produced 350 grams per hour of high-quality nanotubes in a single furnace, compared to 200 grams per hour for the commercial process. Controlling the enthalpy prevents self-extinguishing hot gas pyrolysis. Thus, carbon dioxide enhances the properties and reduces the production cost. This is a near term advance that can go into trial production in the near term. g. Seventh, economic analysis suggests an economic plan forward, producing carbon nanotubes for less than $50 per pound. The use of hydrogen and carbon dioxide as the feedstocks is acceptable from a cost basis, and in fact hydrogen is less expensive than carbon monoxide. Niche applications are available in the near term, though quantities relevant to sequestration remain a far-term goal. h. Eighth, though it was not the research team’s intention to create a new process for producing carbon monoxide, it was realized that almost by accident we demonstrated plasma reforming of carbon dioxide via a plasma version of the reverse Boudouard reaction. Accordingly, we have contacted a major gas manufacturer (Matheson Gas) to determine whether there is interest in creating an industrial version of the process. i. Ninth, a long-range strategy is identified in which a progressively more carbon-conscious world will seek to create solid carbon as a means of sequestering carbon dioxide, impeding its return to the atmosphere. In the long term the price must drop by orders of magnitude with larger production, and assuming success, solid carbon could be the preferred form for sequestration rather than underground storage. If carbon can be made as cheaply as dirt, or nearly so, then it can serve a useful purpose as structural material for housing, soil amendments in agriculture and fillers to modify low areas.

03 NATURAL GAS↗

NASA NTRS1988

NASA specification for manufacturing and performance requirements of NASA standard aerospace nickel-cadmium cells

On November 25, 1985, the NASA Chief Engineer established a NASA-wide policy to maintain and to require the use of the NASA standard for aerospace nickel-cadmium cells and batteries. The Associate Administrator for Safety, Reliability, Maintainability, and Quality Assurance stated on December 29, 1986, the intent to retain the NASA standard cell usage policy established by the Office of the Chief Engineer. The current NASA policy is also to incorporate technological advances as they are tested and proven for spaceflight applications. This policy will be implemented by modifying the existing standard cells or by developing new NASA standards and their specifications in accordance with the NASA's Aerospace Battery Systems Program Plan. This NASA Specification for Manufacturing and Performance Requirements of NASA Standard Aerospace Nickel-Cadmium Cells is prepared to provide requirements for the NASA standard nickel-cadmium cell. It is an interim specification pending resolution of the separator material availability. This specification has evolved from over 15 years of nickel-cadmium cell experience by NASA. Consequently, considerable experience has been collected and cell performance has been well characterized from many years of ground testing and from in-flight operations in both geosynchronous (GEO) and low earth orbit (LEO) applications. NASA has developed and successfully used two standard flight qualified cell designs.

Source record↗

DOE OSTI2024

Equity Considerations in Siting Consolidated Interim Storage Facilities for Commercial Spent Nuclear Fuel

Questions of equity and fairness are often raised by representatives from State, Tribal and local governments and members of the public when resolving conflicts over siting of nuclear facilities. However, the two terms are not synonymous: equity can be quantified while fairness is much more subjective. The Department of Energy's (DOE) December 2021 Request for Information sought input on how to site federal facilities for the temporary, consolidated storage of spent nuclear fuel (SNF) using a consent-based approach. It is anticipated that just such questions about equity and fairness associated with the potential emergence of more than one host site may be raised by the twelve groups of university, nonprofit and private sector partners (Consortia) working to support community engagement, inclusively involve stakeholders, build relationships, and develop innovative forms of mutual learning and public capacity to participate in the consent-based siting process for a federal consolidated interim storage facility during the current Planning & Capacity Building stage of the consent-based siting process. In terms of DOE's Integrated Waste Management System (IWMS), sociopolitical equity concepts are a factor in all aspects of IWMS development and operations and will be particularly applicable should two or more host sites become a possibility, either by the emergence of multiple volunteer hosts or by pursuit as a IWMS program strategy. This paper summarizes recent analyses that explore how four equity metrics - number of states, division of the projected SNF total by the year 2083, current population and land area - might be perceived by host communities, states and regions if two, three or four sites for hosting federal consolidated interim storage facilities were to be contemporaneously realized. Existing institutional arrangements, including Nuclear Regulatory Commission regions, Federal Energy Regulatory Commission regions and Low-Level Radioactive Waste Disposal Compacts, were selected to create hypothetically merged two, three and four-region scenarios to calculate how the four metrics balance out. Projected SNF burden was prioritized with regional contiguity of the consolidated regions a requirement for a functional scenario. The intent was not to promote or suggest any construct as a program objective; the configurations are geopolitical abstractions only to explore potential perceptions of equity. Understanding the possible issues of equity that could arise may benefit program efforts toward achieving a cooperative federalism wherein both the federal and multiple State governments share the goal of manifesting more than one federal consolidated interim storage facility. The main finding is that it is not possible to optimize for all four metrics simultaneously. The analyses demonstrate that trying to create a sense of equity by backfitting a solution to a random population and land distribution will always contain a degree of artificiality.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS1989

Electrical, Electronic, and Electromechanical (EEE) parts management and control requirements for NASA space flight programs

This document establishes electrical, electronic, and electromechanical (EEE) parts management and control requirements for contractors providing and maintaining space flight and mission-essential or critical ground support equipment for NASA space flight programs. Although the text is worded 'the contractor shall,' the requirements are also to be used by NASA Headquarters and field installations for developing program/project parts management and control requirements for in-house and contracted efforts. This document places increased emphasis on parts programs to ensure that reliability and quality are considered through adequate consideration of the selection, control, and application of parts. It is the intent of this document to identify disciplines that can be implemented to obtain reliable parts which meet mission needs. The parts management and control requirements described in this document are to be selectively applied, based on equipment class and mission needs. Individual equipment needs should be evaluated to determine the extent to which each requirement should be implemented on a procurement. Utilization of this document does not preclude the usage of other documents. The entire process of developing and implementing requirements is referred to as 'tailoring' the program for a specific project. Some factors that should be considered in this tailoring process include program phase, equipment category and criticality, equipment complexity, and mission requirements. Parts management and control requirements advocated by this document directly support the concept of 'reliability by design' and are an integral part of system reliability and maintainability. Achieving the required availability and mission success objectives during operation depends on the attention given reliability and maintainability in the design phase. Consequently, it is intended that the requirements described in this document are consistent with those of NASA publications, 'Reliability Program Requirements for Aeronautical and Space System Contractors,' NHB 5300.4(1A-l); 'Maintainability Program Requirements for Space Systems,' NHB 5300.4(1E); and 'Quality Program Provisions for Aeronautical and Space System Contractors,' NHB 5300.4(1B).

Source record↗

NASA NTRS2000

A Plan for Measuring Climatic Scale Global Precipitation Variability: The Global Precipitation Mission

The outstanding success of the Tropical Rainfall Measuring Mission (TRMM) stemmed from a near flawless launch and deployment, a highly successful measurement campaign, achievement of all original scientific objectives before the mission life had ended, and the accomplishment of a number of unanticipated but important additional scientific advances. This success and the realization that satellite rainfall datasets are now a foremost tool in the understanding of decadal climate variability has helped motivate a comprehensive global rainfall measuring mission, called 'The Global Precipitation Mission' (GPM). The intent of this mission is to address looming scientific questions arising in the context of global climate-water cycle interactions, hydrometeorology, weather prediction, the global carbon budget, and atmosphere-biosphere-cryosphere chemistry. This paper addresses the status of that mission currently planed for launch in the early 2007 time frame. The GPM design involves a nine-member satellite constellation, one of which will be an advanced TRMM-like 'core' satellite carrying a dual-frequency Ku-Ka band radar (df-PR) and a TMI-like radiometer. The other eight members of the constellation can be considered drones to the core satellite, each carrying some type of passive microwave radiometer measuring across the 10.7-85 GHz frequency range, likely based on both real and synthetic aperture antenna technology and to include a combination of new lightweight dedicated GPM drones and both co-existing operational and experimental satellites carrying passive microwave radiometers (i.e., SSM/l, AMSR, etc.). The constellation is designed to provide a minimum of three-hour sampling at any spot on the globe using sun-synchronous orbit architecture, with the core satellite providing relevant measurements on internal cloud precipitation microphysical processes. The core satellite also enables 'training' and 'calibration' of the drone retrieval process. Additional information is contained in the original extended abstract.

Smith, Eric A.↗

NASA NTRS1999

Start Up Application Concerns with Field Programmable Gate Arrays (FPGAs)

This note is being published to improve the visibility of this subject, as we continue to see problems surface in designs, as well as to add additional information to the previously published note for design engineers. The original application note focused on designing systems with no single point failures using Actel Field Programmable Gate Arrays (FPGAs) for critical applications. Included in that note were the basic principles of operation of the Actel FPGA and a discussion of potential single-point failures. The note also discussed the issue of startup transients for that class of device. It is unfortunate that we continue to see some design problems using these devices. This note will focus on the startup properties of certain electronic components, in general, and current Actel FPGAs, in particular. Devices that are "power-on friendly" are currently being developed by Actel, as a variant of the new SX series of FPGAs. In the ideal world, electronic components would behave much differently than they do in the real world, The chain, of course, starts with the power supply. Ideally, the voltage will immediately rise to a stable V(sub cc) level, of course, it does not. Aside from practical design considerations, inrush current limits of certain capacitors must be observed and the power supply's output may be intentionally slew rate limited to prevent a large current spike on the system power bus. In any event, power supply rise time may range from less than I msec to 100 msec or more.

Katz, Richard B.↗

NASA NTRS1993

Retrievable payload carrier, next generation Long Duration Exposure Facility: Update 1992

Access to space and cost have been two major inhibitors of low Earth orbit research. The Retrievable Payload Carrier (RPC) Program is a commercial space program which strives to overcome these two barriers to space experimentation. The RPC Program's fleet of spacecraft, ground communications station, payload processing facility, and experienced integration and operations team will provide a convenient 'one-stop shop' for investigators seeking to use the unique vantage point and environment of low Earth orbit for research. The RPC is a regularly launched and retrieved, free-flying spacecraft providing resources adequate to meet modest payload/experiment requirements, and presenting ample surface area, volume, mass, and growth capacity for investigator usage. Enhanced capabilities of ground communications, solar-array-supplied electrical power, central computing, and on-board data storage pick up on the path where NASA's Long Duration Exposure Facility (LDEF) blazed the original technology trail. Mission lengths of 6-18 months, or longer, are envisioned. The year 1992 was designated as the 'International Space Year' and coincides with the 500th anniversary of Christopher Columbus's voyage to the New World. This is a fitting year in which to launch the full scale development of our unique shop of discovery whose intent is to facilitate retrieving technological rewards from another new world: space. Presented is an update on progress made on the RPC Program's development since the November 1991 LDEF Materials Workshop.

Perry, A. T.↗

NASA NTRS2007

Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT)

An effort was initiated by NASA/JSC in 2001 to develop an Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT) for the sizing of Extravehicular Activity System (EVAS) architecture and studies. Its intent was to support space suit development efforts and to aid in conceptual designs for future human exploration missions. Its basis was the Life Support Options Performance Program (LSOPP), a spacesuit and portable life support system (PLSS) sizing program developed for NASA/JSC circa 1990. EVAS_SAT estimates the mass, power, and volume characteristics for user-defined EVAS architectures, including Suit Systems, Airlock Systems, Tools and Translation Aids, and Vehicle Support equipment. The tool has undergone annual changes and has been updated as new data have become available. Certain sizing algorithms have been developed based on industry standards, while others are based on the LSOPP sizing routines. The sizing algorithms used by EVAS_SAT are preliminary. Because EVAS_SAT was designed for use by members of the EVA community, subsystem familiarity on the part of the intended user group and in the analysis of results is assumed. The current EVAS_SAT is operated within Microsoft Excel 2003 using a Visual Basic interface system.

Brown, Cheryl B.↗

NASA NTRS2008

Reusability Studies for Ares I and Ares V Propulsion

With a mission to continue to support the goals of the International Space Station (ISS) and explore beyond Earth orbit, the United States National Aeronautics and Space Administration (NASA) is in the process of launching an entirely new space exploration initiative, the Constellation Program. Even as the Space Shuttle moves toward its final voyage, Constellation is building from nearly half a century of NASA spaceflight experience, and technological advances, including the legacy of Shuttle and earlier programs such as Apollo and the Saturn V rocket. Out of Constellation will come two new launch vehicles: the Ares I crew launch vehicle and the Ares V cargo launch vehicle. With the initial goal to seamlessly continue where the Space Shuttle leaves off, Ares will firstly service the Space Station. Ultimately, however, the intent is to push further: to establish an outpost on the Moon, and then to explore other destinations. With significant experience and a strong foundation in aerospace, NASA is now progressing toward the final design of the First Stage propulsion system for the Ares I. The new launch vehicle design will considerably increase safety and reliability, reduce the cost of accessing space, and provide a viable growth path for human space exploration. To achieve these goals, NASA is taking advantage of Space Shuttle hardware, safety, reliability, and experience. With efforts to minimize technical risk and life-cycle costs, the First Stage office is again pulling from NASA's strong legacy in aerospace exploration and development, most specifically the Space Shuttle Program. Trade studies have been conducted to evaluate lifecycle costs, expendability, and risk reduction. While many first stage features have already been determined, these trade studies are helping to resolve the operational requisites and configuration of the first stage element. This paper first presents an overview of the Ares missions and the genesis of the Ares vehicle design. It then looks at one of the most important trade studies to date, the "Ares I First Stage Expendability Trade Study." The purpose of this study was to determine the utility of flying the first stage as an expendable booster rather than making it reusable. To lower the study complexity, four operational scenarios (or cases) were defined. This assessment then included an evaluation of the development, reliability, performance, and transition impacts associated with an expendable solution. The paper looks at these scenarios from the perspectives of cost, reliability, and performance. The presentation provides an overview of the paper.

Williams, Thomas J.↗