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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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NASA NTRS2016

The "Puck" Energetic Charged Particle Detector: Design, Heritage, and Advancements

Energetic charged particle detectors characterize a portion of the plasma distribution function that plays critical roles in some physical processes, from carrying the currents in planetary ring currents to weathering the surfaces of planetary objects. For several low-resource missions in the past, the need was recognized for a low-resource but highly capable, mass-species-discriminating energetic particle sensor that could also obtain angular distributions without motors or mechanical articulation. This need led to the development of a compact Energetic Particle Detector (EPD), known as the "Puck" EPD (short for hockey puck), that is capable of determining the flux, angular distribution, and composition of incident ions between an energy range of approximately 10 kiloelectronvolts to several megaelectronvolts. This sensor makes simultaneous angular measurements of electron fluxes from the tens of kiloelectronvolts to about 1 megaelectronvolt. The same measurements can be extended down to approximately 1 kiloelectronvolt per nucleon,with some composition ambiguity. These sensors have a proven flight heritage record that includes missions such as MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) and New Horizons, with multiple sensors on each of Juno, Van Allen Probes, and Magnetospheric Multiscale. In this review paper we discuss the Puck EPD design, its heritage, unexpected results from these past missions and future advancements. We also discuss high-voltage anomalies that are thought to be associated with the use of curved foils, which is a new foil manufacturing processes utilized on recent Puck EPD designs. Finally, we discuss the important role Puck EPDs can potentially play in upcoming missions.

Clark, G.↗
NASA NTRS2021

Satellites for long-term monitoring of inland U.S. lakes: The MERIS time series and application for chlorophyll-a

Lakes and other surface fresh waterbodies provide drinking water, recreational and economic opportunities, food, and other critical support for humans, aquatic life, and ecosystem health. Lakes are also productive ecosystems that provide habitats and influence global cycles. Chlorophyll concentration provides a common metric of water quality, and is frequently used as a proxy for lake trophic state. Here, we document the generation and distribution of the complete MEdium Resolution Imaging Spectrometer (MERIS; Appendix A provides a complete list of abbreviations) radiometric time series for over 2300 satellite resolvable inland bodies of water across the contiguous United States (CONUS) and more than 5,000 in Alaska. This contribution greatly increases the ease of use of satellite remote sensing data for inland water quality monitoring, as well as highlights new horizons in inland water remote sensing algorithm development. We evaluate the performance of satellite remote sensing Cyanobacteria Index (CI)-based chlorophyll algorithms, the retrievals for which provide surrogate estimates of phytoplankton concentrations in cyanobacteria dominated lakes. Our analysis quantifies the algorithms' abilities to assess lake trophic state across the CONUS. As a case study, we apply a bootstrapping approach to derive a new CI-to-chlorophyll relationship, ChlBS, which performs relatively well with a multiplicative bias of 1.11 (11%) and mean absolute error of 1.60 (60%). While the primary contribution of this work is the distribution of the MERIS radiometric timeseries, we provide this case study as a roadmap for future stakeholders' algorithm development activities, as well as a tool to assess the strengths and weaknesses of applying a single algorithm across CONUS.

MERIS timeseries↗
NASA NTRS2005

The features of self-assembling organic bilayers important to the formation of anisotropic inorganic materials in microgravity conditions

Materials with directional properties are opening new horizons in a variety of applications including chemistry, electronics, and optics. Structural, optical, and electrical properties can be greatly augmented by the fabrication of composite materials with anisotropic microstructures or with anisotropic particles uniformly dispersed in an isotropic matrix. Examples include structural composites, magnetic and optical recording media, photographic film, certain metal and ceramic alloys, and display technologies including flat panel displays. The new applications and the need for model particles in scientific investigations are rapidly out-distancing the ability to synthesize anisotropic particles with specific chemistries and narrowly distributed physical characteristics (e.g. size distribution, shape, and aspect ratio).

Talham, Daniel R.↗
NASA NTRS2019

Bumper: A Tool for Analyzing Spacecraft Micrometeoroid and Orbital Debris Risk

“Bumper” is NASA’s computer program for analyzing spacecraft micrometeoroid and orbital debris (MMOD) risk. Bumper was developed in the late-1980s and has been continuously used and maintained since. The user base has grown from a few government entities to now include numerous commercial entities as well. The NASA Johnson Space Center (JSC) Hypervelocity Impact Technology (HVIT) Team is responsible for all aspects of the Bumper software. Bumper has been used to characterize MMOD risk on hundreds of spacecraft. All of the International Space Station (ISS) modules, visiting vehicles and numerous external components and systems have been analyzed. Bumper was used to analyze each of the Space Shuttle missions since STS-50. The Orion Multi-Purpose Crew Vehicle (MPCV) MMOD shielding is being developed using Bumper as well. Bumper has also been used on numerous telescopes (Hubble, James Webb, and Fermi Gamma-ray Space Telescopes), scientific probes (Stardust, New Horizons, Parker Solar Probe), and Earth observation satellites (Landsat, Joint Polar Satellite System). Bumper is also being used to analyze the micrometeoroid risk and support design of the Deep Space Gateway (DSG) and Mars Sample Return (MSR) missions. The HVIT Bumper Configuration Control Board (CCB) ensures that all changes to the code are approved, reviewed, and documented. Most of the changes are made to add new MMOD damage “ballistic limit equations” (BLEs). BLEs are typically added in response to completion of a hypervelocity impact (HVI) test series and development of an associated BLE. Other less frequent changes include updates of the debris or meteoroid environment models, feature enhancements, and feature retirement. Some BLEs are commercially sensitive and/or proprietary, so the CCB also manages code user-version control and software distribution. The current version – “Bumper 3” – is a FORTRAN executable that utilizes a 64-bit architecture. Bumper 3 has numerous features that make it a powerful tool for analyzing spacecraft MMOD risk. Bumper uses the latest orbital debris and micrometeoroid environment models. Bumper also easily processes large spacecraft geometry models, recognizes hidden surfaces, permits BLE assignment by name or number, and conducts quality checks of the spacecraft geometry model. Bumper 3 can also be used to estimate the effects of particle penetration through thin, high-standoff distance hardware components such as solar arrays and radiators. This is done using a special HVIT-developed technique know as the “3-Part Analysis.” The paper introduces the Bumper 3 MMOD risk analysis code and provides an example MMOD risk assessment showing Bumper’s role in the overall MMOD protection design process.

Lear, Dana M.↗
NASA NTRS2011

Wide-Field Infrared Survey Telescope (WFIRST) Interim Report

The New Worlds, New Horizons (NWNH) in Astronomy and Astrophysics 2010 Decadal Survey prioritized the community consensus for ground-based and space-based observatories. Recognizing that many of the community s key questions could be answered with a wide-field infrared survey telescope in space, and that the decade would be one of budget austerity, WFIRST was top ranked in the large space mission category. In addition to the powerful new science that could be accomplished with a wide-field infrared telescope, the WFIRST mission was determined to be both technologically ready and only a small fraction of the cost of previous flagship missions, such as HST or JWST. In response to the top ranking by the community, NASA formed the WFIRST Science Definition Team (SDT) and Project Office. The SDT was charged with fleshing out the NWNH scientific requirements to a greater level of detail. NWNH evaluated the risk and cost of the JDEM-Omega mission design, as submitted by NASA, and stated that it should serve as the basis for the WFIRST mission. The SDT and Project Office were charged with developing a mission optimized for achieving the science goals laid out by the NWNH re-port. The SDT and Project Office opted to use the JDEM-Omega hardware configuration as an initial start-ing point for the hardware implementation. JDEM-Omega and WFIRST both have an infrared imager with a filter wheel, as well as counter-dispersed moderate resolution spectrometers. The primary advantage of space observations is being above the Earth's atmosphere, which absorbs, scatters, warps and emits light. Observing from above the atmosphere enables WFIRST to obtain precision infrared measurements of the shapes of galaxies for weak lensing, infrared light-curves of supernovae and exoplanet microlensing events with low systematic errors, and infrared measurements of the H hydrogen line to be cleanly detected in the 1<z<2 redshift range important for baryon acoustic oscillation (BAO) dark energy measurements. The Infrared Astronomical Satellite (IRAS), the Cosmic Background Explorer (COBE), Herschel, Spitzer, and Wide-field Infrared Sur-vey Explorer (WISE) are all space missions that have produced stunning new scientific advances by going to space to observe in the infrared. This interim report describes progress as of June 2011 on developing a requirements flowdown and an evaluation of scientific performance. An Interim Design Reference Mission (IDRM) configuration is presented that is based on the specifications of NWNH with some refinements to optimize the design in accordance with the new scientific requirements. Analysis of this WFIRST IDRM concept is in progress to ensure the capability of the observatory is compatible with the science requirements. The SDT and Project will continue to refine the mission concept over the coming year as design, analysis and simulation work are completed, resulting in the SDT s WFIRST Design Reference Mission (DRM) by the end of 2012.

Green, J.↗
NASA NTRS2014

Development of NASA's Small Fission Power System for Science and Human Exploration

Exploration of our solar system has brought great knowledge to our nation's scientific and engineering community over the past several decades. As we expand our visions to explore new, more challenging destinations, we must also expand our technology base to support these new missions. NASA's Space Technology Mission Directorate is tasked with developing these technologies for future mission infusion and continues to seek answers to many existing technology gaps. One such technology gap is related to compact power systems (greater than 1 kWe) that provide abundant power for several years where solar energy is unavailable or inadequate. Below 1 kWe, Radioisotope Power Systems have been the workhorse for NASA and will continue, assuming its availability, to be used for lower power applications similar to the successful missions of Voyager, Ulysses, New Horizons, Cassini, and Curiosity. Above 1 kWe, fission power systems become an attractive technology offering a scalable modular design of the reactor, shield, power conversion, and heat transport subsystems. Near term emphasis has been placed in the 1-10kWe range that lies outside realistic radioisotope power levels and fills a promising technology gap capable of enabling both science and human exploration missions. History has shown that development of space reactors is technically, politically, and financially challenging and requires a new approach to their design and development. A small team of NASA and DOE experts are providing a solution to these enabling FPS technologies starting with the lowest power and most cost effective reactor series named "Kilopower" that is scalable from approximately 1-10 kWe.

Solar System↗
NASA NTRS2015

Development of NASA's Small Fission Power System for Science and Human Exploration

Exploration of our solar system has brought many exciting challenges to our nations scientific and engineering community over the past several decades. As we expand our visions to explore new, more challenging destinations, we must also expand our technology base to support these new missions. NASAs Space Technology Mission Directorate is tasked with developing these technologies for future mission infusion and continues to seek answers to many existing technology gaps. One such technology gap is related to compact power systems (1 kWe) that provide abundant power for several years where solar energy is unavailable or inadequate. Below 1 kWe, Radioisotope Power Systems have been the workhorse for NASA and will continue to be used for lower power applications similar to the successful missions of Voyager, Ulysses, New Horizons, Cassini, and Curiosity. Above 1 kWe, fission power systems become an attractive technology offering a scalable modular design of the reactor, shield, power conversion, and heat transport subsystems. Near term emphasis has been placed in the 1-10kWe range that lies outside realistic radioisotope power levels and fills a promising technology gap capable of enabling both science and human exploration missions. History has shown that development of space reactors is technically, politically, and financially challenging and requires a new approach to their design and development. A small team of NASA and DOE experts are providing a solution to these enabling FPS technologies starting with the lowest power and most cost effective reactor series named Kilopower that is scalable from approximately 1-10 kWe.

Heat Transfer↗
NASA NTRS2023

The Trans-Heliospheric Survey - Radial Trends in Plasma Parameters Across the Heliosphere

Context. Though the solar wind is characterized by spatial and temporal variability across a wide range of scales, long-term averages of in situ measurements have revealed clear radial trends: changes in average values of basic plasma parameters (e.g., density, temperature, and speed) and a magnetic field with a distance from the Sun. Aims. To establish our current understanding of the solar wind's average expansion through the heliosphere, data from multiple spacecraft needed to be combined and standardized into a single dataset. Methods. In this study, data from twelve heliospheric and planetary spacecraft - Parker Solar Probe (PSP), Helios 1 and 2, Mariner 2 and 10, Ulysses, Cassini, Pioneer 10 and 11, New Horizons, and Voyager 1 and 2 - were compiled into a dataset spanning over three orders of magnitude in heliocentric distance. To avoid introducing artifacts into this composite dataset, special attention was given to the solar cycle, spacecraft heliocentric elevation, and instrument calibration. Results. The radial trend in each parameter was found to be generally well described by a power-law fit, though up to two break points were identified in each fit. Conclusions. These radial trends are publicly released here to benefit research groups in the validation of global heliospheric simulations and in the development of new deep-space missions such as Interstellar Probe.

Bennett A Maruca↗
NASA NTRS2008

Radioisotope Power: A Key Technology for Deep Space Exploration

A Radioisotope Power System (RPS) generates power by converting the heat released from the nuclear decay of radioactive isotopes, such as Plutonium-238 (Pu-238), into electricity. First used in space by the U.S. in 1961, these devices have enabled some of the most challenging and exciting space missions in history, including the Pioneer and Voyager probes to the outer solar system; the Apollo lunar surface experiments; the Viking landers; the Ulysses polar orbital mission about the Sun; the Galileo mission to Jupiter; the Cassini mission orbiting Saturn; and the recently launched New Horizons mission to Pluto. Radioisotopes have also served as a versatile heat source for moderating equipment thermal environments on these and many other missions, including the Mars exploration rovers, Spirit and Opportunity. The key advantage of RPS is its ability to operate continuously, independent of orientation and distance relative to the Sun. Radioisotope systems are long-lived, rugged, compact, highly reliable, and relatively insensitive to radiation and other environmental effects. As such, they are ideally suited for missions involving long-lived, autonomous operations in the extreme conditions of space and other planetary bodies. This paper reviews the history of RPS for the U.S. space program. It also describes current development of a new Stirling cycle-based generator that will greatly expand the application of nuclear-powered missions in the future.

Schmidt, George↗
NASA NTRS2009

Radioisotope Power: A Key Technology for Deep Space Explorations

A Radioisotope Power System (RPS) generates power by converting the heat released from the nuclear decay of radioactive isotopes, such as Plutonium-238 (Pu-238), into electricity. First used in space by the U.S. in 1961, these devices have enabled some of the most challenging and exciting space missions in history, including the Pioneer and Voyager probes to the outer solar system; the Apollo lunar surface experiments; the Viking landers; the Ulysses polar orbital mission about the Sun; the Galileo mission to Jupiter; the Cassini mission orbiting Saturn; and the recently launched New Horizons mission to Pluto. Radioisotopes have also served as a versatile heat source for moderating equipment thermal environments on these and many other missions, including the Mars exploration rovers, Spirit and Opportunity. The key advantage of RPS is its ability to operate continuously, independent of orientation and distance relative to the Sun. Radioisotope systems are long-lived, rugged, compact, highly reliable, and relatively insensitive to radiation and other environmental effects. As such, they are ideally suited for missions involving long-lived, autonomous operations in the extreme conditions of space and other planetary bodies. This paper reviews the history of RPS for the U.S. space program. It also describes current development of a new Stirling cycle-based generator that will greatly expand the application of nuclear-powered missions in the future.

Schmidt, George R.↗
NASA NTRSDate not supplied

U.S. Spacesuit Knowledge Capture – Creation, Curation, and Dissemination

The U.S. spacesuit is a special system that has intrigued and fascinated the world since Neil Armstrong set foot on the Moon in 1969. With over 50 years since that momentous achievement, NASA is planning to land the first woman and next man on the Moon in the near future. This goal begets the need to build a new spacesuit, a spacesuit created from the legacy knowledge of the Extravehicular Mobility Unit (EMU), combined with knowledge gained from technology development over the decades. As NASA transitions to its new horizon, the U.S. Spacesuit Knowledge Capture (SKC) Program is poised to help. The SKC Program’s primary function has been to capture, curate, and disseminate spacesuit-related knowledge among scientists, engineers, and technicians. The SKC Program was created in 2007 to capture knowledge primarily from spacesuit subject-matter experts (SMEs) who were retiring from NASA. These SMEs had 30 to 50 years of spacesuit knowledge. Over the years, the SKC Program has evolved and expanded its scope with a current focus on complementing the buildup of the Exploration EMU (xEMU) at the Johnson Space Center. As part of this focus, the SKC Program recently teamed with the xEMU Community of Practice (CoP) for knowledge sharing. The xEMU CoP provides a forum where early career engineers, professionals new to human spaceflight, and the xEMU community can come together regularly to seek guidance, share knowledge, meet their peers, discover resources, and ask questions. The CoP created an environment where the knowledge can be easily and routinely captured and recorded. The recorded events are archived and curated in an SKC Program library and disseminated as appropriate. This paper details the roles that the SKC Program and CoP play in the xEMU buildup, along with the navigation of the creation, curation, and dissemination processes.

Cinda Chullen↗
NASA NTRS2007

NASA's Discovery Program: Moving Toward the Edge (of the Solar System)

NASA's Planetary Science , Division sponsors a competitive program of small spacecraft missions with the goal of performing focused science investigations that complement NASA's larger planetary science explorations at relatively low cost. The goal of the Discovery program is to launch many smaller missions with fast development times to increase our understanding of the solar system by exploring the planets, dwarf planets, their moons, and small bodies such as comets and asteroids. Discovery missions are solicited from the broad planetary science community approximately every 2 years. Active missions within the Discovery program include several with direct scientific or engineering connections to potential future missions to the edge of the solar system and beyond. In addition to those in the Discovery program are the missions of the New Frontiers program. The first New Frontiers mission. is the New Horizons mission to Pluto, which will explore this 38-AU distant dwarf planet and potentially some Kuiper Belt objects beyond. The Discovery program's Dawn mission, when launched in mid-2007, will use ion drive as its primary propulsion system. Ion propulsion is one of only two technologies that appear feasible for early interstellar precursor missions with practical flight times. The Kepler mission will explore the structure and diversity of extrasolar planetary systems, with an emphasis on the detection of Earth-size planets around other stars. Kepler will survey nearby solar systems searching for planets that may fall within the habitable zone,' a region surrounding a star within which liquid water may exist on a planet's surface - an essential ingredient for life as we know it. With its open and competitive approach to mission selections, the Discovery program affords scientists the opportunity to propose missions to virtually any solar system destination. With its emphasis on science and proven openness to the use of new technologies such as ion propulsion, missions flown as part of the program will test out technologies needed for future very deep-space exploration and potentially take us to these difficult and distant destinations.

Johnson, Les↗
NASA NTRS2005

Lunar and Planetary Science XXXVI, Part 12

Topics discussed include: The Ancient Lakes in Hellas Basin Region as Seen Through the First Year of Mars Express HRSC-Camera; DISR Observations of Craters at Titan at the Huygens Landing Site: Insights Anticipated; The Sun s Dust Disk - Discovery Potential of the New Horizons Mission During Interplanetary Cruise; Evidence for Aqueously Precipitated Sulfates in Northeast Meridiani Using THEMIS and TES Data; Integrated Spectroscopic Studies of Anhydrous Sulfate Minerals; Venusian Channel Formation as a Subsurface Process; Reexamination of Quartz Grains from the Permian-Triassic Boundary Section at Graphite Peak, Antarctica; Observations of Calcium Sulfate Deposits at High Latitudes by OMEGA/Mex at Km/Pixel Resolutions; Observations of the North Permanent Cap of Mars in Mid-Summer by OMEGA/MEX at km per Pixel Resolutions; Classification and Distribution of Patterned Ground in the Southern Hemisphere of Mars Genesis: Removing Contamination from Sample Collectors; Thermal Characterization of Fe3O4 Nanoparticles Formed from Poorly Crystalline Siderite; Hydrogen Abundances in Metal Grains from the Hammadah Al Hamra (HaH) 237 Metal-rich Chondrite: A Test of the Nebular-Formation Theory; REE and Some Other Trace Elements Distributions of Mineral Separates in Atlanta (EL6); The Composition and Origin of the Dewar Geochemical Anomaly; Asteroid Modal Mineralogy Using Hapke Mixing Models: Testing the Utility of Spectral Lookup Tables; and The Huygens Mission at Titan: Results Highlights. (sup 182)Hf-(sup 182)W Chronometry and an Early Differentiation in the Parent Body of Ureilites Ground Penetrating Radar in Sedimentary Rocks Mars, Always Cold, Sometimes Wet: New Constraints on Mars Denudation Rates and Climate Evolution from Analog Studies at Haughton Crater, Devon Island, High Arctic Europa s Porous Ice Rheology and Implications for Ice-penetrating Radar Scattering Loss Surface Generated Cracks on Europa

Source record↗
NASA NTRS2018

Sixth Annual NASA Ames Space Science and Astrobiology Jamboree

Welcome to the Sixth Annual NASA Ames Research Center, Space Science and Astrobiology Jamboree at NASA Ames Research Center (ARC). The Space Science and Astrobiology Division consists of over 60 Civil Servants, with more than 120 Cooperative Agreement Research Scientists, Post-Doctoral Fellows, Science Support Contractors, Visiting Scientists, and many other Research Associates. Within the Division there is engagement in scientific investigations over a breadth of disciplines including Astrobiology, Astrophysics, Exobiology, Exoplanets, Planetary Systems Science, and many more. The Division's personnel support NASA spacecraft missions (current and planned), including SOFIA, K2, MSL, New Horizons, JWST, WFIRST, and others. Our top-notch science research staff is spread amongst three branches in five buildings at ARC. Naturally, it can thus be difficult to remain abreast of what fellow scientific researchers pursue actively, and then what may present and/or offer regarding inter-Branch, intra-Division future collaborative efforts. In organizing this annual jamboree, the goals are to offer a wholesome, one-venue opportunity to sense the active scientific research and spacecraft mission involvement within the Division; and to facilitate communication and collaboration amongst our research scientists. Annually, the Division honors one senior research scientist with a Pollack Lecture, and one early career research scientist with an Outstanding Early Career Space Scientist Lecture. For the Pollack Lecture, the honor is bestowed upon a senior researcher who has made significant contributions within any area of research aligned with space science and/or astrobiology. This year we are pleased to honor Linda Jahnke. With the Early Career Lecture, the honor is bestowed upon an early-career researcher who has substantially demonstrated great promise for significant contributions within space science, astrobiology, and/or, in support of spacecraft missions addressing such disciplines. This year we are pleased to honor Amanda Cook. We hope that you will make time to join us for the day in meeting fellow Division members, expanding knowledge of our activities, and creating new collaborations within the Space Science and Astrobiology Division.

Hollingsworth, Jeffery↗
NASA NTRSDate not supplied

A window on the composition of the early solar nebula: 2014MU69, Pluto, and Phoebe

The initial chemical composition of any solar nebula will depend upon the degree to which 1) organic and ice components form on dust grains, 2) organic and molecular species form in the gas phase, 3) organics and ices are exchanged between the gas and solid state, and 4) the precursor and newly formed (more complex) materials survive and are modified in the developing planetary system. Infrared and radio observations of star-forming regions reveal that complex chemistry occurs on icy grains, sometimes before stars even form. Additional processing, through the protosolar disk and within the solar nebula further modifies most, but probably not all, of the initial materials. In fact, the modern Solar System still carries a fraction of its interstellar inheritance [Alexander et al., 2017]. Here we focus on three examples of small bodies in our Solar System, each containing chemical and dynamical clues to its origin and evolution: the small, cold-classical Kuiper Belt object (KBO) 2014MU69 , Pluto and Saturn’s moon, Phoebe. The New Horizons flyby of 2014 MU69 has given the first view of an unaltered body composed of material originally in the solar nebula at ~45 AU. The spectrum reveals methanol ice (not commonly found), a possible detection of water ice (Stern et al. 2019). Pluto’s internal and surface inventory of volatiles and complex organics, together with active geological processes including cryo-volcanism, indicate a surprising level of activity on a body in the outermost region of the Solar System, and the fluid that emerges from subsurface reservoirs may contain material inherited from the solar nebula (Cruikshank et al. 2019). Meanwhile, Saturn's captured moon, Phoebe, carries high D/H in H2O [Clark et al. 2018)], and complex organics (Cruikshank et al. 2008), both consistent with its formation in, and inheritance from, the outer solar nebula. Together, these objects provide windows on the origin and evolution of our Solar System and constraints to be considered in future chemical and physical models of PPDs. The Spitzer Space telescope discovered the ring of dust around Saturn that emanated from the bombardment of Phoebe in the recent past, dislodging primitive Solar System material from deep within that satellite. In addition, Spitzer has provided detailed studies of the chemistry of star forming regions where methanol and other ices are readily observed. As a result of these and other observations, protoplanetary disk models are beginning to combine both dynamical and chemical complexities into their codes, resulting in new insights for exoplanetary systems.

Yvonne J. Pendleton↗
NASA NTRS1976

The characteristics of the planned National Transonic Facility

The National Transonic Facility is a high Reynolds number transonic wind tunnel designed to satisfy the research and development needs of NASA, DOD, and industry. The facility design incorporates the cryogenic approach to achieving high Reynolds numbers with manageable model loads. By using temperature as a test variable, a unique capability to clearly separate aeroelastic, Reynolds number, and Mach number effects will be possible. This capability will open new horizons in transonic aerodynamic research. The tunnel design including unique features and operating envelopes is described. A brief overview of the general operating arrangement and the schedule for facility construction is presented.

Mckinney, L. W.↗
NASA NTRS1984

Ccds: Their Cause and Cure

Charge coupled devices (CCDs) have opened new horizons in the optical astronomy. Most of the presently existing astronomical CCD systems are oriented and designed primarily for work on faint objects. The use of CCDs for high precision work on bright objects remains to be explored. Issues and problems specific to (CCDs) are covered in detail. The important structural characteristics of CCDs are that they are integrating, self scanned, photon counting (one selection for each detected photon), solid state devices. The typical physical sizes are of the order of 1 - 3 cm, and typical raster formats of 500x500 pixels (TI), 320x512 (RCA), 385x576 (GEC), 800x800 (TI), and 1500x1500 (GEC) should be available soon. Typical (and optimal) operating temperatures are around -100 C, with liquid N2 as the most common coolant. Some CCDs are physically warped. This causes focus variations across the surface, which amount to a spatially variable PSF. Other relevant properties of CCDs as detectors and a comparison with some other astronomical detectors are given.

Djorgovski, S.↗
NASA NTRS1996

A Study of the X-Ray Emission from Three Radio Pulsars

The subject grant is for work on a study of x-ray emission from isolated pulsars. The purpose of the study was to: determine whether the pulsars were x-ray sources; and, if so, search for evidence of pulsations at the known radio period; and study the nature of the x-ray emission. Observation of the pulsar PSR 0355+54 were obtained, and the analysis of these data is complete. These results were reported at the 183rd AAS Meeting, and in a paper entitled 'X-Ray Emission from PSR 0355+54' which as published in the The Astrophysical Journal. Also obtained an approx. 3 ks PSPC observations of PSR 1642-03. A summary of the results from these data were reported in a Conference Proceedings for the 'New Horizon of X-ray Astronomy' symposium. In addition, as part of a study with a student from the SAO Summer Intern Program, I incorporated ROSAT archival data in an extended study of pulsar emission. These results were reported at the 185th AAS Meeting, and in a paper entitled 'Soft X-ray Emission from Selected Isolated Pulsars' which was published in The Astrophysical Journal (Letters).

Slane, Patrick O.↗