Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Alternative Identifiers”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7

PROcess Based Diagnostics PROBE

Many of the aspects of the climate system that are of the greatest interest (e.g., the sensitivity of the system to external forcings) are emergent properties that arise via the complex interplay between disparate processes. This is also true for climate models most diagnostics are not a function of an isolated portion of source code, but rather are affected by multiple components and procedures. Thus any model-observation mismatch is hard to attribute to any specific piece of code or imperfection in a specific model assumption. An alternative approach is to identify diagnostics that are more closely tied to specific processes -- implying that if a mismatch is found, it should be much easier to identify and address specific algorithmic choices that will improve the simulation. However, this approach requires looking at model output and observational data in a more sophisticated way than the more traditional production of monthly or annual mean quantities. The data must instead be filtered in time and space for examples of the specific process being targeted.We are developing a data analysis environment called PROcess-Based Explorer (PROBE) that seeks to enable efficient and systematic computation of process-based diagnostics on very large sets of data. In this environment, investigators can define arbitrarily complex filters and then seamlessly perform computations in parallel on the filtered output from their model. The same analysis can be performed on additional related data sets (e.g., reanalyses) thereby enabling routine comparisons between model and observational data. PROBE also incorporates workflow technology to automatically update computed diagnostics for subsequent executions of a model. In this presentation, we will discuss the design and current status of PROBE as well as share results from some preliminary use cases.

PROBE↗

Effective and Environmentally Compliant Cleaner Solstice® Performance Fluid

On January 1, 2015, the United States Environmental Protection Agency identified exemptions on the continued use of the hydrochlorofluorocarbon (HCFC)-225ca and -225cb. As these solvents are commonly used in cleaning and verification of aerospace propulsion systems using liquid and gaseous oxygen, the NESC supported the Agency initiative to identify and characterize acceptable alternate fluids. Honeywell’s Solstice® Performance Fluid (PF), PF-high purity (HP), and PF-HP spray are an effective nonflammable cleaning solution system, with a favorable toxicity profile and low environmental impact. Solstice PF is suitable for electronics, metal, and precision cleaning. It can be used in vapor degreasing equipment and may be dispensed with a propellant to create an aerosol contact cleaner. Solstice PF has been shown to have negligible ozone depletion and a global warming potential of 1. With these characterized environmental and solvency properties, Solstice PF, PF-HP, or PF-HP spray may be an excellent choice for a variety of cleaning applications.

Effective Compliant Cleaner↗

Determining Locations by Use of Networks of Passive Beacons

Networks of passive radio beacons spanning moderate-sized terrain areas have been proposed to aid navigation of small robotic aircraft that would be used to explore Saturn s moon Titan. Such networks could also be used on Earth to aid navigation of robotic aircraft, land vehicles, or vessels engaged in exploration or reconnaissance in situations or locations (e.g., underwater locations) in which Global Positioning System (GPS) signals are unreliable or unavailable. Prior to use, it would be necessary to pre-position the beacons at known locations that would be determined by use of one or more precise independent global navigation system(s). Thereafter, while navigating over the area spanned by a given network of passive beacons, an exploratory robot would use the beacons to determine its position precisely relative to the known beacon positions (see figure). If it were necessary for the robot to explore multiple, separated terrain areas spanned by different networks of beacons, the robot could use a long-haul, relatively coarse global navigation system for the lower-precision position determination needed during transit between such areas. The proposed method of precise determination of position of an exploratory robot relative to the positions of passive radio beacons is based partly on the principles of radar and partly on the principles of radio-frequency identification (RFID) tags. The robot would transmit radar-like signals that would be modified and reflected by the passive beacons. The distance to each beacon would be determined from the roundtrip propagation time and/or round-trip phase shift of the signal returning from that beacon. Signals returned from different beacons could be distinguished by means of their RFID characteristics. Alternatively or in addition, the antenna of each beacon could be designed to radiate in a unique pattern that could be identified by the navigation system. Also, alternatively or in addition, sets of identical beacons could be deployed in unique configurations such that the navigation system could identify their unique combinations of radio-frequency reflections as an alternative to leveraging the uniqueness of the RFID tags. The degree of dimensional accuracy would depend not only on the locations of the beacons but also on the number of beacon signals received, the number of samples of each signal, the motion of the robot, and the time intervals between samples. At one extreme, a single sample of the return signal from a single beacon could be used to determine the distance from that beacon and hence to determine that the robot is located somewhere on a sphere, the radius of which equals that distance and the center of which lies at the beacon. In a less extreme example, the three-dimensional position of the robot could be determined with fair precision from a single sample of the signal from each of three beacons. In intermediate cases, position estimates could be refined and/or position ambiguities could be resolved by use of supplementary readings of an altimeter and other instruments aboard the robot.

Okino, Clayton↗

Future of alternate fuels for turbine engines

The fuel property variations that were identified to be of concern with the utilization of alternate fuels for aircraft turbine engines are related to the potential problem areas.

Schelp, H.↗

Advanced Fuels Can Reduce the Cost of Getting Into Space

Rocket propellant and propulsion technology improvements can reduce the development time and operational costs of new space vehicle programs, and advanced propellant technologies can make space vehicles safer and easier to operate, and can improve their performance. Five major areas have been identified for fruitful research: monopropellants, alternative hydrocarbons, gelled hydrogen, metallized gelled propellants, and high-energy-density propellants. During the development of the NASA Advanced Space Transportation Plan, these technologies were identified as those most likely to be effective for new NASA vehicles. Several NASA research programs had fostered work in fuels under the topic Fuels and Space Propellants for Reusable Launch Vehicles in 1996 to 1997. One component of this topic was to promote the development and commercialization of monopropellant rocket fuels, hypersonic fuels, and high-energy-density propellants. This research resulted in the teaming of small business with large industries, universities, and Government laboratories. This work is ongoing with seven contractors. The commercial products from these contracts will bolster advanced propellant research. Work also is continuing under other programs, which were recently realigned under the "Three Pillars" of NASA: Global Civil Aviation, Revolutionary Technology Leaps, and Access to Space. One of the five areas is described below, and its applications and effect on future missions is discussed. This work is being conducted at the NASA Lewis Research Center with the assistance of the NASA Marshall Space Flight Center. The regenerative cooling of spacecraft engines and other components can improve overall vehicle performance. Endothermic fuels can absorb energy from an engine nozzle and chamber and help to vaporize high-density fuel before it enters the combustion chamber. For supersonic and hypersonic aircraft, endothermic fuels can absorb the high heat fluxes created on the wing leading edges and other aerodynamically heated components. Dual-fuel options are also possible, where endothermic hydrocarbon fuels are used for the lower speed portions of flight below Mach 8, and hydrogen fuel is used for the final acceleration to the upper stage separation velocity.

Palaszewski, Bryan A.↗

Considerations for an Integrated UAS CNS Architecture

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is investigating revolutionary and advanced universal, reliable, always available, cyber secure and affordable Communication, Navigation, Surveillance (CNS) options for all altitudes of UAS operations. In Spring 2015, NASA issued a Call for Proposals under NASA Research Announcements (NRA) NNH15ZEA001N, Amendment 7 Subtopic 2.4. Boeing was selected to conduct a study with the objective to determine the most promising candidate technologies for Unmanned Air Systems (UAS) air-to-air and air-to-ground data exchange and analyze their suitability in a post-NextGen NAS environment. The overall objectives are to develop UAS CNS requirements and then develop architectures that satisfy the requirements for UAS in both controlled and uncontrolled air space. This contract is funded under NASAs Aeronautics Research Mission Directorates (ARMD) Aviation Operations and Safety Program (AOSP) Safe Autonomous Systems Operations (SASO) project and proposes technologies for the Unmanned Air Systems Traffic Management (UTM) service.There is a need for accommodating large-scale populations of Unmanned Air Systems (UAS) in the national air space. Scale obviously impacts capacity planning for Communication, Navitation, and Surveillance (CNS) technologies. For example, can wireless communications data links provide the necessary capacity for accommodating millions of small UASs (sUAS) nationwide? Does the communications network provide sufficient Internet Protocol (IP) address space to allow air traffic control to securely address both UAS teams as a whole as well as individual UAS within each team? Can navigation and surveillance approaches assure safe route planning and safe separation of vehicles even in crowded skies?Our objective is to identify revolutionary and advanced CNS alternatives supporting UASs operating at all altitudes and in all airspace while accurately navigating in the absence of navigational aids. These CNS alternatives must be reliable, redundant, always available, cyber-secure, and affordable for all types of vehicles including small UAS to large transport category aircraft. The approach will identify CNS technology candidates that can meet the needs of the range of UAS missions to specific air traffic management applications where they will be most beneficial and cost effective.

Templin, Fred L.↗

Considerations for an Integrated UAS CNS Architecture

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is investigating revolutionary and advanced universal, reliable, always available, cyber secure and affordable Communication, Navigation, Surveillance (CNS) options for all altitudes of UAS operations. In Spring 2015, NASA issued a Call for Proposals under NASA Research Announcements (NRA) NNH15ZEA001N, Amendment 7 Subtopic 2.4. Boeing was selected to conduct a study with the objective to determine the most promising candidate technologies for Unmanned Air Systems (UAS) air-to-air and air-to-ground data exchange and analyze their suitability in a post-NextGen NAS environment. The overall objectives are to develop UAS CNS requirements and then develop architectures that satisfy the requirements for UAS in both controlled and uncontrolled air space. This contract is funded under NASAs Aeronautics Research Mission Directorates (ARMD) Aviation Operations and Safety Program (AOSP) Safe Autonomous Systems Operations (SASO) project and proposes technologies for the Unmanned Air Systems Traffic Management (UTM) service.There is a need for accommodating large-scale populations of Unmanned Air Systems (UAS) in the national air space. Scale obviously impacts capacity planning for Communication, Navigation, and Surveillance (CNS) technologies. For example, can wireless communications data links provide the necessary capacity for accommodating millions of small UASs (sUAS) nationwide? Does the communications network provide sufficient Internet Protocol (IP) address space to allow air traffic control to securely address both UAS teams as a whole as well as individual UAS within each team? Can navigation and surveillance approaches assure safe route planning and safe separation of vehicles even in crowded skies?Our objective is to identify revolutionary and advanced CNS alternatives supporting UASs operating at all altitudes and in all airspace while accurately navigating in the absence of navigational aids. These CNS alternatives must be reliable, redundant, always available, cyber-secure, and affordable for all types of vehicles including small UAS to large transport category aircraft. The approach will identify CNS technology candidates that can meet the needs of the range of UAS missions to specific air traffic management applications where they will be most beneficial and cost effective.

Templin, Fred L.↗

Exploring the Fate of Nitrogen Heterocycles in Complex Prebiotic Mixtures

A long standing question in the field of prebiotic chemistry is the origin of the genetic macromolecules DNA and RNA. DNA and RNA have very complex structures with repeating subunits of nucleotides, which are composed of nucleobases (nitrogen heterocycles) connected to sugar-phosphate. Due to the instability of some nucleobases (e.g. cytosine), difficulty of synthesis and instability of D-ribose, and the likely scarcity of polyphosphates necessary for the modern nucleotides, alternative nucleotides have been proposed for constructing the first genetic material. Thus, we have begun to investigate the chemistry of nitrogen heterocycles in plausible, complex prebiotic mixtures in an effort to identify robust reactions and potential alternative nucleotides. We have taken a complex prebiotic mixture produced by a spark discharge acting on a gas mixture of N2, CO2, CH4, and H2, and reacted it with four nitrogen heterocycles: uracil, 5-hydroxymethyluracil, guanine, and isoxanthopterin (2-amino-4,7-dihydroxypteridine). The products of the reaction between the spark mixture and each nitrogen heterocycle were characterized by liquid chromatography coupled to UV spectroscopy and Orbitrap mass spectrometry. We found that the reaction between the spark mixtUl'e and isoxanthopterin formed one major product, which was a cyanide adduct. 5-hydroxymethyluracil also reacted with the spark mixture to form a cyanide adduct, uracil-5-acetonitrile, which has been synthesized previously by reacting HCN with S-hydroxymethyluracil. Unlike isoxanthopterin, the chromatogram of the 5-hydroxymethyluracil reaction was much more complex with multiple products including spark-modified dimers. Additionally, we observed that HMU readily self-polymerizes in solution to a variety of oligomers consistent with those suggested by Cleaves. Guanine and uracil, the biological nucleobases, did not react with the spark mixture, even at high temperature (100 C). This suggests that there are alternative nucleobases which are more reactive under prebiotic conditions and may have been involved in producing precursor nucleotides.

Smith, Karen E.↗

Small V/STOL aircraft analysis, volume 1

A study has been made of the economic viability of advanced V/STOL aircraft concepts in performing general aviation missions. A survey of general aviation aircraft users, operators, and manufacturers indicated that personnel transport missions formulated around business executive needs, commuter air service, and offshore oil supply are the leading potential areas of application using VTOL aircraft. Advanced VTOL concepts potentially available in the late 1970 time period were evaluated as alternatives to privately owned contemporary aircraft and commercial airline service in satisfying these personnel transport needs. Economic analysis incorporating the traveler's value of time as the principle figure of merit were used to identify the relative merits of alternative VTOL air transportation concepts.

Smith, K. R., Jr.↗

Root Source Analysis/ValuStream[Trade Mark] - A Methodology for Identifying and Managing Risks

Root Source Analysis (RoSA) is a systems engineering methodology that has been developed at NASA over the past five years. It is designed to reduce costs, schedule, and technical risks by systematically examining critical assumptions and the state of the knowledge needed to bring to fruition the products that satisfy mission-driven requirements, as defined for each element of the Work (or Product) Breakdown Structure (WBS or PBS). This methodology is sometimes referred to as the ValuStream method, as inherent in the process is the linking and prioritizing of uncertainties arising from knowledge shortfalls directly to the customer's mission driven requirements. RoSA and ValuStream are synonymous terms. RoSA is not simply an alternate or improved method for identifying risks. It represents a paradigm shift. The emphasis is placed on identifying very specific knowledge shortfalls and assumptions that are the root sources of the risk (the why), rather than on assessing the WBS product(s) themselves (the what). In so doing RoSA looks forward to anticipate, identify, and prioritize knowledge shortfalls and assumptions that are likely to create significant uncertainties/ risks (as compared to Root Cause Analysis, which is most often used to look back to discover what was not known, or was assumed, that caused the failure). Experience indicates that RoSA, with its primary focus on assumptions and the state of the underlying knowledge needed to define, design, build, verify, and operate the products, can identify critical risks that historically have been missed by the usual approaches (i.e., design review process and classical risk identification methods). Further, the methodology answers four critical questions for decision makers and risk managers: 1. What s been included? 2. What's been left out? 3. How has it been validated? 4. Has the real source of the uncertainty/ risk been identified, i.e., is the perceived problem the real problem? Users of the RoSA methodology have characterized it as a true bottoms up risk assessment.

Brown, Richard Lee↗

SIM PlanetQuest: Progress Report

SIM PlanetQuest, a micro-arcsecond astrometry space mission, has been impacted by significant changes in NASA priorities over the last two years, resulting in the mission being indefinitely delayed. The SIM team has responded by investigating alternative mission concepts based upon completed SIM technology. Several alternative mission concepts have been identified, ranging from a planets-only concept, to versions of SIM, called SIM-Lite, that still address the full breadth of SIM science envisioned by two previous National Academy Astrophysics Decadal Surveys but with lower precision and reduced throughput. These mission concepts, Planet Hunter and SIM-Lite, are significantly more affordable and may fit into a nearer-term future scenario than the full SIM PlanetQuest would. This paper describes the current state of the SIM project, including its design and technology, and the alternative mission concepts for the use of these designs and technology.

SIM-Lite↗

Data catalog of satellite experiments

This catalog is divided into three sections: data description contains descriptions of data available at or through NSSDC as well as descriptions of the experiments and spacecraft from which the data originated; and supporting data contains brief descriptions of space environment models and programs distributed by NSSDC. Section 3 is a series of indexes that contain: (1) a listing of all spacecraft, experiment, and data descriptions presented in Section 1 plus tables indicating the period for which each spacecraft was operational; (2) an index of all spacecraft described here, identified by common names and alternate names; (3) a listing of the original experiment institutions for all experiments described; (4) a listing of the investigators associated with the experiments and their current affiliations; and (5) an index of all experiments sorted by phenomenon measured.

Source record↗

Data catalog of satellite experiments

The availability of space science data, a description of the data, and a description of the services supplied by the National Space Science Data Center (NSSDC) is presented. A series of cumulative indexes that reference the data descriptions contain: (1) a chronological listing of all spacecraft, experiments, and data descriptions; (2) an index of all spacecraft described, identified by common names and alternate names; (3) a listing of the original experiment institutions for experiments described; (4) a listing of the investigators associated with the experiments and their current affiliations; and (5) two displays of information about experiment data coverage for fields and particle data and a listing of all experiments sorted by phenomenon measured.

Source record↗

Maneuver strategy for a possible Pioneer 11 extended mission

The Jupiter-bound Pioneer 11 spacecraft was launched in April 1973, eight months before the Jupiter encounter of the front-running twin spacecraft, Pioneer 10. Depending on the content of the Pioneer 10 science, the Pioneer 11 mission objectives may be modified to explore different regions about Jupiter, including an aimpoint region providing for an extended trajectory to Saturn. Following launch, early maneuver aiming strategies were designed to retain a later retargeting maneuver capability to repeat Pioneer 10 or to encounter alternate Jupiter aimpoints. This paper identifies the ground rules and information required for the adaptive design of these strategies, considering a variety of mission objectives and Project constraints for later retargeting maneuvers.

Frauenholz, R. B.↗

Digital system identification and its application to digital flight control

On-line system identification of linear discrete systems for implementation in a digital adaptive flight controller is considered by the conventional extended Kalman filter and a decoupling process in which the linear state estimation problem and the linear parameter identification problem are each treated separately and alternately. Input requirements for parameter identifiability are established using the standard conditions of observability for a time variant system. Experimental results for simulated linearized lateral aircraft motion are included along with the effect of different initialization and updating procedures for the priming trajectory used by the filter.

Kotob, S.↗

Power processor design considerations for a solar electric propulsion spacecraft

Propulsion power processor design options are described. The propulsion power processor generated the regulated dc voltages and currents from a solar array source of a solar electric propelled spacecraft. The power processor consisted of 12 power supplies that provide the regulated voltages and currents necessary to power a 30-cm mercury ion thruster. The design options for processing unregulated solar array power and for generating the regulated power required by each supply are studied. The technical approaches utilized in the developed design and the technological limitation of the identified design options are discussed. Alternate approaches for delivering power to a number of mercury ion thrusters and methods of optimizing are described. It was concluded that this power processor design should be considered for application in solar electric propulsion missions of the future.

Costogue, E. N.↗

Hydrogen detection study

The effectiveness was assessed of a hydrogen (H2) detection concept for regenerative environmental control life support systems (EC/LSS). The concept evaluated was that utilized for the electrochemical depolarized concentrator (EDC) design, constructed, and tested for the EC/LSS space station prototype program. The EDC contains combustible gas detectors (CGDs) which were evaluated with H2. The CGDs were evaluated for linearity, position sensitivity, reproducibility, ambient effects, repeatability, speed of response, recovery time, and interchangeability. The effectiveness of CGDs located within the EDC for sensing H2 leaks at various line replaceable units in the subsystem was determined. The effects of H2 leak rate, H2 concentration of leaking gas and air currents in the vicinity of the EDC were determined. Proposed improvements for the H2 detection concept were documented and alternative H2 detection approaches were identified and analyzed.

Shumar, J. W.↗

The next 25 years: Industrialization of space: Rationale for planning

The goals of NASA's space industralization program include contributing to increased productivity on earth without taxing the environment, generating new values through extraterrestrial productivity, and providing new growth options for the future which include the permanent settlement of space and long-range colonization and exploration projects. In planning the long-range space program based on essentially utilitarian aspects, without losing sight of the more humanistically significant long term, and to forecast associated technology requirements, a realistic approach is obtained by combining extrapolative and normative planning modes so that common stepping stones can be identified. In the extrapolative view, alternative futures are projected on the basis of past and current trends and tendencies. In the normative view, some ideal state in the far future is envisioned or postulated, and policies and decisions are directed toward its attainment.

Vonputtkamer, J.↗