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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.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Lunar crater arcs

An analysis has been made of the tendency of large lunar craters to lie along circles. A catalog of the craters at least 50 km in diameter was prepared first, noting position, diameter, rim sharpness and completion, nature of underlying surface, and geological age. The subset of those craters 50-400 km in diameter was then used as input to computer programs which identified each 'family' of four or more craters of selected geological age lying on a circular arc. For comparison, families were also identified for randomized crater models in which the crater spatial density was matched to that on the moon, either overall or separately for mare and highland areas. The observed frequency of lunar arcuate families was statistically highly significantly greater than for the randomized models, for craters classified as either late-pre-Imbrian (Nectarian), middle pre-Imbrian, or early pre-Imbrian, as well as for a number of larger age-classes. The lunar families tend to center in specific areas of the moon; these lie in highlands rather than maria and are different for families of Nectarian craters than for pre-Nectarian. The origin of the arcuate crater groupings is not understood.

Jaffe, L. D.↗
NASA NTRS1982

Positive electrode processing for Hughes NiH2 cells

The basic procedures were developed for the manufacture of nickel cadmium batteries. An electrochemical impregnation in an aqueous ethanol solution is used in this process. Several additional controls were instituted for production of flight electrodes, including a Hughes controlled MCD, a solution reserved exclusively for the impregnation of Hughes positive electrodes a system of complete traceability for individual electrodes, an electrical characterization test to provide information on weight and capacity at the plaque level, and a stress test to provide data on capacity, weight, and physical parameters at the electrode level.

Bleser, C. A.↗
NASA NTRS1986

Solar irradiance variations from photometry of active regions

The Extreme Limb Photometer (ELP) has been used to measure the irradiance fluctuation of the sun due to selected active regions. Forty-five active regions that were completely scanned at various disk positions are included in the analysis. The contribution of these active regions to a global solar irradiance fluctuation has been correlated with photometric sunspot and facular indices (PSI and PFI) using published values of sunspot and calcium plage areas. The measured ELP fluctuations are converted to a global brightness fluctuation, Delta B/B. The sunspot component of Delta B/B correlates with PSI with r = 0.95. The facular component of Delta B/B correlates with PFI with r = 0.72. The expression for PFI is important to the question of energy balance between sunspots and faculae and the results presented here are not incompatible with energy balance between the two phenomena; that is the energy deficit of sunspots may be balanced by the energy excess of faculae.

Chapman, G. A.↗
NASA NTRS1993

Planet X - No dynamical evidence in the optical observations

It is shown that the alleged 'unexplained anomalies in the motion of Uranus' disappear when one properly accounts for the correct value of the mass of Neptune and properly adjusts the orbit of Uranus to the observational data. Also, it is shown that each of the 'irregularities in the measured positions of Neptune' has a complete explanation within the framework of the presently known solar system. As a check of certainty, an actual planetary ephemeris is integrated which well fits the observations of Uranus. Minor systematic errors do remain in the data, but they are very small; they are easily explained by a number of uncertainties in the observations themselves. There is now known to be a mass concentration of significant size in the outer solar system - 1992 QB1. In comparison to any of the major planets, though, this object is miniscule. For the meridian circle observations, there is still no evidence which requires or even indicates the existence of any planet-sized object; there remains no need to hypothesize the existence of a tenth planet in the solar system.

Standish, E. M., Jr.↗
NASA NTRS1994

Orthostatic responses to dietary sodium restriction during heat acclimation

Several studies have shown that individuals consuming low-salt diets and working in the heat have an increased risk or incidence of heat injury, suggestive of inadequate cardiovascular adjustment. Furthermore, others have shown that prolonged work in hot climates can precipitate orthostatic hypotension and syncope. This study was designed to evaluate the effects of moderate-salt (MS) and low-salt (LS) diets on the circulatory responses and incidence of presyncopal symptoms to an orthostatic test (OT) during successive days of heat acclimation (HA). Seventeen unacclimatized male soldiers (mean +/- SE: age 20+/-1 yrs) participated in this two-phase study. The first phase consisted of a seven day dietary stabilization period during which all subjects consumed similar diets of about 4000 kcal/day containing 8g NaCl and lived in a dormitory setting (21 C, 30% RH). The second phase commenced on day eight and consisted of dietary NaCl restriction and 10 days HA (days 8-17). Volunteers were randomly assigned to either the MS diet (n=9) providing 8g NaCl/day or the LS diet (n=8) furnishing just 4g NaCl/day. The acquisition of HA was manifested in both groups by reductions in exercising rectal temperature and heart rate (HR); these characteristics were similar in the MS and LS diets. The OT was performed at 21 C on day seven of the stabilization phase and on days 9, 11, 13, 15, and 17 of the HA phase, before and after 8.5 hr of intermittent treadmill walking in a hot environment. Blood pressure (BP) and HR responses at 1,2, and 4 min and any presyncopal symptoms were recorded after assuming an upright position from recumbency. All subjects completed the OT before and after prolonged exercise in the heat without incidence of either hypotension or presyncopal symptoms irrespective of dietary-salt intake and day of HA. The results indicate that the prolonged work in the heat can be performed without orthostatic hypotension or syncope while consuming 4g NaCl/day with adequate fluid replacement. Furthermore, the circulatory responses to OT showed no improvement with successive days of HA irrespective of dietary-salt intake.

Szlyk, Patricia C.↗
NASA NTRS1995

End Effector Coupler/Decoupler

Coupling/decoupling device offers benefits of both stiffness and repositioning. Permits end effector to be released (decoupled) from robot arm while attached to workpiece, and realigned and recoupled to arm when end effector task completed. Relieves necessity for accurate positioning of robot and workpiece, and compensates for deformations initiated by changes in temperature as well as normal machining variations.

Smith, Russell W.↗
NASA NTRS2008

Flight-Like Ground Demonstrations of Precision Maneuvers for Spacecraft Formations

Synchronized formation rotations are a common maneuver for planned precision formations. In such a rotation, attitudes remain synchronized with relative positions, as if the spacecraft were embedded in a virtual rigid body. Further, since synchronized rotations are needed for science data collection, this maneuver requires the highest precision control of formation positions and attitudes. A recently completed, major technology milestone for the Terrestrial Planet Finder Interferometer is the high-fidelity, ground demonstration of precision synchronized formation rotations. These demonstrations were performed in the Formation Control Testbed (FCT), which is a flight-like, multi-robot formation testbed. The FCT is briefly introduced, and then the synchronized rotation demonstration results are presented. An initial error budget consisting of formation simulations is used to show the connection between ground performance and TPF-I flight performance.

formation flying↗
NASA NTRS2012

Positron Interactions with Atoms and Ions

Dirac, in 1928, combining the ideas of quantum mechanics and the ideas of relativity invented the well-known relativistic wave equation. In his formulation, he predicted an antiparticle of the electron of spin n-bar/2. He thought that this particle must be a proton. Dirac published his interpretation in a paper 'A theory of electrons and protons.' It was shown later by the mathematician Hermann Weyl that the Dirac theory was completely symmetric between negative and positive particles and the positive particle must have the same mass as that of the electron. In his J. Robert Oppenheimer Memorial Prize Acceptance Speech, Dirac notes that 'Blackett was really the first person to obtain hard evidence for the existence of a positron but he was afraid to publish it. He wanted confirmation, he was really over cautious.' Positron, produced by the collision of cosmic rays in a cloud chamber, was detected experimentally by Anderson in 1932. His paper was published in Physical Review in 1933. The concept of the positron and its detection were the important discoveries of the 20th century. I have tried to discuss various processes involving interactions of positrons with atoms and ions. This includes scattering, bound states and resonances. It has not been possible to include the enormous work which has been carried out during the last 40 or 50 years in theory and measurements.

Bhatia, Anand K.↗
NASA NTRS2012

Lightning Jump Algorithm and Relation to Thunderstorm Cell Tracking, GLM Proxy and Other Meteorological Measurements

The lightning jump algorithm has a robust history in correlating upward trends in lightning to severe and hazardous weather occurrence. The algorithm uses the correlation between the physical principles that govern an updraft's ability to produce microphysical and kinematic conditions conducive for electrification and its role in the development of severe weather conditions. Recent work has demonstrated that the lightning jump algorithm concept holds significant promise in the operational realm, aiding in the identification of thunderstorms that have potential to produce severe or hazardous weather. However, a large amount of work still needs to be completed in spite of these positive results. The total lightning jump algorithm is not a stand-alone concept that can be used independent of other meteorological measurements, parameters, and techniques. For example, the algorithm is highly dependent upon thunderstorm tracking to build lightning histories on convective cells. Current tracking methods show that thunderstorm cell tracking is most reliable and cell histories are most accurate when radar information is incorporated with lightning data. In the absence of radar data, the cell tracking is a bit less reliable but the value added by the lightning information is much greater. For optimal application, the algorithm should be integrated with other measurements that assess storm scale properties (e.g., satellite, radar). Therefore, the recent focus of this research effort has been assessing the lightning jump's relation to thunderstorm tracking, meteorological parameters, and its potential uses in operational meteorology. Furthermore, the algorithm must be tailored for the optically-based GOES-R Geostationary Lightning Mapper (GLM), as what has been observed using Very High Frequency Lightning Mapping Array (VHF LMA) measurements will not exactly translate to what will be observed by GLM due to resolution and other instrument differences. Herein, we present some of the promising aspects and challenges encountered in utilizing objective tracking and GLM proxy data, as well as recent results that demonstrate the value added information gained by combining the lightning jump concept with traditional meteorological measurements.

Schultz, Christopher J.↗
NASA NTRS1982

Use of a geosynchronous satellite within the SARSAT/COSPAS system

Operational characteristics of combined LEO SARSAT/COSPAS and GEO spacecraft for localization of aircraft and seacraft emitting distress signals are described. Although 121.5 MHz capability is now included in all SARSAT/COSPAS satellites, limitations on the number of simultaneous signals which can be processed at that frequency due to atmospheric noise indicates the employment of the 406 MHz band. Additionally, the necessity for on-board storage for later transmission when the satellites are in a favorable position is leading to the implementation of GEO stationed relays for real-time transmission and processing of distress signals. Six NOAA spacecraft and two Soviet satellites are planned, with a completed system offering high detection probability, position location, worldwide coverage, coded messages, and high capacity (406 MHz). A significant factor in use of a GEO relay system is noted to be the signal to noise temperature of the repeater.

Goudy, P.↗
NASA NTRS1994

Imager for Mars Pathfinder (IMF)

The IMP camera is a near-surface sensing experiment with many capabilities beyond those normally associated with an imager. It is fully pointable in both elevation and azimuth with a protected, stowed position looking straight down. Stereo separation is provided with two optical paths; each has a 12-position filter wheel. The primary function of the camera, strongly tied to mission success, is to take a color panorama of the surrounding terrain. IMP requires approximately 120 images to give a complete downward hemisphere from the deployed position. IMP provides the geologist, and everyone else, a view of the local morphology with millimeter-tometer-scale resolution over a broad area. In addition to the general morphology of the scale, IMP has a large compliment of specially chosen filters to aid in both the identification of the mineral types and their degree of weathering.

Smith, Peter H.↗
NASA NTRS1997

Surface Development and Test Facility (SDTF) New R&D Simulator for Airport Operations

A new simulator, the Surface Development and Test Facility (SDTF) is under construction at the NASA Ames Research Center in Mountain View, California. Jointly funded by the FAA (Federal Aviation Administration) and NASA, the SDTF will be a testbed for airport surface automation technologies of the future. The SDTF will be operational in the third quarter of 1998. The SDTF will combine a virtual tower with simulated ground operations to allow evaluation of new technologies for safety, effectiveness, reliability, and cost benefit. The full-scale level V tower will provide a seamless 360 degree high resolution out-the-window view, and a full complement of ATC (air traffic control) controller positions. The imaging system will be generated by two fully-configured Silicon Graphics Onyx Infinite Reality computers, and will support surface movement of up to 200 aircraft and ground vehicles. The controller positions, displays and consoles can be completely reconfigured to match the unique layout of any individual airport tower. Dedicated areas will accommodate pseudo-airport ramp controllers, pseudo-airport operators, and pseudo-pilots. Up to 33 total personnel positions will be able to participate in simultaneous operational scenarios. A realistic voice communication infrastructure will emulate the intercom and telephone communications of a real airport tower. Multi-channel audio and video recording and a sophisticated data acquisition system will support a wide variety of research and development areas, such as evaluation of automation tools for surface operations, human factors studies, integration of terminal area and airport technologies, and studies of potential airport physical and procedural modifications.

Dorighi, Nancy S.↗
NASA NTRS1984

Specification of a NAVSTAR Global Positioning System (GPS) receiver for a differential GPS ground system

One step towards the successful completion of a functional ground unit for the Differential Global Positioning System (DGPS) will be in choosing a currently available GPS receiver that will accurately measure the propagation times of the satellite signals and have the capability to be electrically interfaced with and controlled by a Digital Equipment Corporation (DEC) PDP-11/34A computer. The minimum requirements and characteristics of a NAVSTAR Global Positioning System (GPS) receiver are described. The specific technical specifications addressed include data accuracies and resolutions, receiver interface/external control, enclosure dimensions and mounting requirements, receiver operation, and environmental specifications.

Mccall, D. L.↗
NASA NTRS1977

DSN research and technology support

The activities of the Venus Station (DSS 13) and the Microwave Test Facility (MTF) during the period October 11, 1976, through February 13, 1977, are discussed. A significant effort on implementation of equipment for the planned conversion of DSS 13 to unattended operation is discussed. The Receiver and Microwave Subsystem are near completion, and the new feedcone and position encoders are implemented onto the 26-m antenna. Support of the 400-kW X-band radar, located at DSS 14, is reported, and the activities of the DSN High Power Transmitter Maintenance Facility (HPTMF), located at DSS 13 and MTF, are discussed. The successful completion of the first series of observations planned for VLBI validation is reported and significant station maintenance activities are covered. Clock synchronization transmissions to DSS 43 and DSS 63 are reported, and an evaluation of any pointing errors in the 26-m antenna position transducer are made.

Jackson, E. B.↗
NASA NTRS2012

Hands-Free Transcranial Color Doppler Probe

Current transcranial color Doppler (TCD) transducer probes are bulky and difficult to move in tiny increments to search and optimize TCD signals. This invention provides miniature motions of a TCD transducer probe to optimize TCD signals. The mechanical probe uses a spherical bearing in guiding and locating the tilting crystal face. The lateral motion of the crystal face as it tilts across the full range of motion was achieved by minimizing the distance between the pivot location and the crystal face. The smallest commonly available metal spherical bearing was used with an outer diameter of 12 mm, a 3-mm tall retaining ring, and 5-mm overall height. Small geared motors were used that would provide sufficient power in a very compact package. After confirming the validity of the basic positioning concept, optimization design loops were completed to yield the final design. A parallel motor configuration was used to minimize the amount of space wasted inside the probe case while minimizing the overall case dimensions. The distance from the front edge of the crystal to the edge of the case was also minimized to allow positioning of the probe very close to the ear on the temporal lobe. The mechanical probe is able to achieve a +/-20deg tip and tilt with smooth repeatable action in a very compact package. The enclosed probe is about 7 cm long, 4 cm wide, and 1.8 cm tall. The device is compact, hands-free, and can be adjusted via an innovative touchscreen. Positioning of the probe to the head is performed via conventional transducer gels and pillows. This device is amendable to having advanced software, which could intelligently focus and optimize the TCD signal.

Chin, Robert↗
NASA NTRS1994

The Mars Observer differential one-way range demonstration

Current methods of angular spacecraft positioning using station differenced range data require an additional observation of an extragalactic radio source (quasar) to estimate the timing offset between the reference clocks at the two Deep Space Stations. The quasar observation is also used to reduce the effects of instrumental and media delays on the radio metric observable by forming a difference with the spacecraft observation (delta differential one-way range, delta DOR). An experiment has been completed using data from the Global Positioning System satellites to estimate the station clock offset, eliminating the need for the quasar observation. The requirements for direct measurement of the instrumental delays that must be made in the absence of a quasar observation are assessed. Finally, the results of the 'quasar-free' differential one-way range, or DOR, measurements of the Mars Observer spacecraft are compared with those of simultaneous conventional delta DOR measurements.

Kroger, P. M.↗
NASA NTRS2013

Modeling the Skills and Practices of Scientists through an “All-Inclusive” Comparative Planetology Student Research Investigation

To effectively prepare the nation's future Science, Technology, Engineering, and Mathematics (STEM) workforce, students in today's classrooms need opportunities to engage in authentic experiences that model skills and practices used by STEM professionals. Relevant, real-world authentic research experiences allow students to behave as scientists as they model the process of science. This enables students to get a true sense of STEM-related professions and also allows them to develop the requisite knowledge, skills, curiosity, and creativity necessary for success in STEM careers. Providing professional development and opportunities to help teachers infuse research in the classroom is one of the primary goals of the Expedition Earth and Beyond (EEAB) program. EEAB, facilitated by the Astromaterials Research and Exploration Science (ARES) Directorate at the NASA Johnson Space Center, is an Earth and planetary science education program designed to inspire, engage, and educate teachers and students in grades 5-12 by getting them actively involved with exploration, discovery, and the process of science. The program combines the expertise of scientists and educators to ensure the professional development provided to classroom teachers is scientifically valid and also recognizes classroom constraints. For many teachers, facilitating research in the classroom can be challenging. In addition to addressing required academic standards and dealing with time constraints, challenges include structuring a research investigation the entire class can successfully complete. To build educator confidence, foster positive classroom research experiences, and enable teachers to help students model the skills and practices of scientists, EEAB has created an "allinclusive" comparative planetology research investigation activity. This activity addresses academic standards while recognizing students (and teachers) potentially lack experience with scientific practices involved in conducting research. Designed as an entry level research engagement investigation, the activity introduces, illustrates, and teaches the skills involved in each step of the research process. Students use astronaut photos, provided through the ARES Crew Earth Observations (CEO) payload on the International Space Station (ISS) as well as remote sensing imagery of other planetary worlds. By including all the necessary tools to complete the investigation, students can focus on gaining experience in the process of science. Additionally, students are able to extend their experience of modeling the skills and practices of scientists through the opportunity to request new data of Earth from the ISS. Professional development offered through in-person and webinar trainings, along with the resources provided, enable educators to gain first-hand experience implementing a structured research investigation in the classroom. Through data and feedback collected from teachers, this type of "all-inclusive" investigation activity aims to become a model that can be utilized for other research topics and STEM disciplines.

Graff, Paige↗
NASA NTRS2007

Research on the International Space Station: Understanding Future Potential from Current Accomplishments

In November 2007, the International Space Station (ISS) will have supported seven years of continuous presence in space, with 15 Expeditions completed. These years have been characterized by the numerous technical challenges of assembly as well as operational and logistical challenges related to the availability of transportation by the Space Shuttle. During this period, an active set of early research objectives have also been accomplished alongside the assembly. This paper will review the research accomplishments on ISS to date, with the objective of drawing insights on the potential of future research following completion of ISS assembly. By the end of Expedition 15, an expected 121 U.S.-managed investigations will have been conducted on ISS, with 91 of these completed. Many of these investigations include multiple scientific objectives, with an estimated total of 334 scientists served. Through February 2007, 101 scientific publications have been identified. Another 184 investigations have been sponsored by ISS international partners, which independently track their scientists served and results publication. Through this survey of U.S. research completed on ISS, three different themes will be addressed: (1) How have constraints on transportation of mass to orbit affected the types of research successfully completed on the ISS to date? What lessons can be learned for increasing the success of ISS as a research platform during the period following the retirement of the Space Shuttle? (2) How have constraints on crew time for research during assembly and the active participation of crewmembers as scientists affected the types of research successfully completed on the ISS to date? What lessons can be learned for optimizing research return following the increase in capacity from 3 to 6 crewmembers (planned for 2009)? What lessons can be learned for optimizing research return after assembly is complete? (3) What do early research results indicate about the various scientific disciplines represented in investigations on ISS? Are there lessons specific to human research, technology development, life sciences, and physical sciences that can be used to increase future research accomplishments? Research has been conducted and completed on ISS under a set of challenging constraints during the past 7 years. The history of research accomplished on ISS during this time serves as an indicator of the value and potential of ISS when full utilization begins. By learning from our early experience in completing research on ISS, NASA and our partners can be positioned to optimize research returns as a full crew complement comes onboard, assembly is completed, and research begins in full.

Robinson, Julie A.↗