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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 19 records
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NASA NTRS1986

The spectral development of Comet P/Halley from August 1985 to June 1986

Spectra of comet Halley were obtained every month from 1985 Aug. to 1986 June, from 5200 to 10,400 A at a spectral resolution of 12 A. Spatial extent is 200" along the slit. A variety of spatially resolved spectra with the slit along the tail and perpendicular to the tail were recorded. Emission species observed are C2, CN, NH2, H2O(+), (OI) and NaI. The 2-0 C2 Phillips band is detected at 8750 A, and from its intensity ratio of 1/9 to the 0-1 Swan band a preliminary C2 singlet to triplet intercombination probability of less than 10 to the minus 7th power is derived. Sodium emission is observed stongly only in 1986 Mar. data.

Fink, Uwe↗
NASA NTRS1981

Moderate temperature Na cells. III - Electrochemical and structural studies of Cr0.5V0.5S2 and its Na intercalates

Experimental results are reported on the behavior of a rechargeable Na cell incorporating a Cr0.5V0.5S2 cathode. The cell operates at 130 C and uses as electrolyte a 1M solution of NaI in 1,2-bis(2-methoxy-ethoxy)ethane (triglyme). The mechanism of discharge of Cr0.5V0.5S2 involves Na intercalation. It is found that the maximum rechargeable capacity of the Cr0.5V0.5S2 cathode is 0.7 e(overbar)/mol. With an average cell voltage of 1.9 V, the theoretical specific energy of the cathode is 273 W-hr/kg.

Abraham, K. M.↗
NASA NTRS1988

Gamma radiation background measurements from Spacelab 2

A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, Earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

Paciesas, William S.↗
NASA NTRS1989

Gamma radiation background measurements from Spacelab 2

A Nuclear Radiation Monitor incorporating a NaI(Tl) scintillation detector was flown as part of the verification flight instrumentation on the Spacelab 2 mission, July 29 to August 6, 1985. Gamma-ray spectra were measured with better than 20 s resolution throughout most of the mission in the energy range 0.1 to 30 MeV. Knowledge of the decay characteristics and the geomagnetic dependence of the counting rates enable measurement of the various components of the Spacelab gamma-ray background: prompt secondary radiation, earth albedo, and delayed induced radioactivity. The status of the data analysis and present relevant examples of typical background behavior are covered.

Paciesas, William S.↗
NASA NTRS1997

Optical and Atomic Force Microscopy Characterization of PbI2 Quantum Dots

Lead iodide (PbI2) clusters were synthesized from the chemical reaction of NaI (or KI) with Pb(NO3)2 in H2O, D2O, CH3OH, and C3H7OH media. The observation of the absorption features above 350 nm with the help of integrating sphere accessory strongly suggests the quantum dot formation of PbI2 in solution. Spectral comparison between the synthesized PbI2 clusters in solution and PbI2 nanophase by impregnation of PbI2 in four different pore-sized porous silica indicates that the PbI2 cluster size in solution is less than 2.5 nm in lateral dimension. Atomic force microscopy (AFM) measurements show that the PbL clusters deposited onto three different molecularly flat surfaces are single-layered. The measured height is 1.0 - 0.1 nm. The swollen layer thickness can be attributed to the intralayer contraction from the strong lateral interaction among PbI2 molecules, which is supported by ab initio calculation. Raman scattering measurement of LO and TO modes of PbI2 in bulk and in the confined state were also conducted in 50-150 cu cm region. The observed three bands at 74, %, 106 1/cm are assigned to TO2, LO2, and LO, mode, respectively. The relatively small red-shift in LO modes may be caused by the surface phonon polaritons of PbI2 nanophase in the porous silica.

Mu, R.↗
NASA NTRS1985

Observation of hard X-rays from the Crab pulsar and A0535+26

The Crab pulsar PSR0531+21 was observed in a balloon flight from the Xianghe Balloon Station (China). Data were obtained in the range 20 to 200 keV with a poswish hard X-ray telescope which comprised a 150 sq cm primary crystal of 5 mm thick CsI(T1) which actively shielded the lower 2 pi steradians by a 5 cm thick NaI(T1) crystal. The scintillation pulses originating in CsI and NaI crystals are distinguished by pulse shape discrimination. The telescope has a field of view of approximately 4 deg H psi H pi determined by graded shield and collimator. The effective geometric area of the detector is 116 sq cm. It is noted that when folding a data flow on a long period interference from the data acquisition, transmission and recording system considerably affect the result.

Wu, M.↗
NASA NTRS2012

Observations of Accreting Pulsars with the FERMI-GBM

The Gamma-ray Burst Monitor (GBM) on-board Fermi comprises 12 NaI detectors spanning the 8-1000 keV band and 2 BGO detectors spanning the 100 keV to 40 MeV band. These detectors view the entire unocculted sky, providing long (approximately 40 ks/day) observations of accreting pulsars daily, which allow long-term monitoring of spin-frequencies and pulsed uxes via epoch-folded searches plus daily blind searches for new pulsars. Phase averaged uxes can be measured using the Earth occultation technique. In this talk I will present highlights of GBM accretion-powered pulsar monitoring such as the discovery of a torque reversal in 4U1626-67, a high-energy QPO in A0535+26, and evidence for a stable accretion disk in OAO 1657-415.

Wilson-Hodge, Colleen↗
NASA NTRS2008

Assessment of the NASA Astrobiology Institute

Astrobiology is a scientific discipline devoted to the study of life in the universe--its origins, evolution, distribution, and future. It brings together the physical and biological sciences to address some of the most fundamental questions of the natural world: How do living systems emerge? How do habitable worlds form and how do they evolve? Does life exist on worlds other than Earth? As an endeavor of tremendous breadth and depth, astrobiology requires interdisciplinary investigation in order to be fully appreciated and examined. As part of a concerted effort to undertake such a challenge, the NASA Astrobiology Institute (NAI) was established in 1998 as an innovative way to develop the field of astrobiology and provide a scientific framework for flight missions. Now that the NAI has been in existence for almost a decade, the time is ripe to assess its achievements. At the request of NASA's Associate Administrator for the Science Mission Directorate (SMD), the Committee on the Review of the NASA Astrobiology Institute undertook the assignment to determine the progress made by the NAI in developing the field of astrobiology. It must be emphasized that the purpose of this study was not to undertake a review of the scientific accomplishments of NASA's Astrobiology program, in general, or of the NAI, in particular. Rather, the objective of the study is to evaluate the success of the NAI in achieving its stated goals of: 1. Conducting, supporting, and catalyzing collaborative interdisciplinary research; 2. Training the next generation of astrobiology researchers; 3. Providing scientific and technical leadership on astrobiology investigations for current and future space missions; 4. Exploring new approaches, using modern information technology, to conduct interdisciplinary and collaborative research among widely distributed investigators; and 5. Supporting outreach by providing scientific content for use in K-12 education programs, teaching undergraduate classes, and communicating directly with the public. The committee s assessment of the NAI's progress in these five areas is presented in Chapters 2 to 6, respectively.

Source record↗
NASA NTRS1973

Spectrum of atmospheric gamma rays to 10 MeV at lambda = 40 deg

Results of measurements of the differential counting rate spectra due to atmospheric gamma rays as a function of altitude to 3.6 g/sq cm over Texas. Two gain settings and a 128-channel pulse height analyzer were used to cover the range from 0.2 to 10 MeV. The detector was a 7.6 x 7.6 cm NaI crystal, which was surrounded on five sides by a 2-cm-thick plastic anticoincidence shield for charged particle rejection. The system had a nearly isotropic response to photons above 0.2 MeV. The spectrum at ceiling appeared as a steep continuum with a power-law index of about 1.4. The only obvious feature was the 0.51-MeV positron annihilation line. The spectral shape was independent for depths less than 20 g/sq cm, the absolute intensity varying in proportion to the intensity of the cosmic ray secondary charged particles. Also, at depths less than 30 g/sq cm the observed flux variation with altitude can be described in terms of an empirical depth-dependent source function.

Peterson, L. E.↗
NASA NTRS2003

The National Aerospace Initiative (NAI): Technologies For Responsive Space Access

The Secretary of Defense has set new goals for the Department of Defense (DOD) to transform our nation's military forces. The Director for Defense Research and Engineering (DDR&E) has responded to this challenge by defining and sponsoring a transformational initiative in Science and Technology (S&T) - the National Aerospace Initiative (NAI) - which will have a fundamental impact on our nation's military capabilities and on the aerospace industry in general. The NAI is planned as a joint effort among the tri-services, DOD agencies and National Aeronautics and Space Administration (NASA). It is comprised of three major focus areas or pillars: 1) High Speed Hypersonics (HSH), 2) Space Access (SA), and 3) Space Technology (ST). This paper addresses the Space Access pillar. The NAI-SA team has employed a unique approach to identifying critical technologies and demonstrations for satisfying both military and civilian space access capabilities needed in the future. For planning and implementation purposes the NAI-SA is divided into five technology subsystem areas: Airframe, Propulsion, Flight Subsystems, Operations and Payloads. Detailed technology roadmaps were developed under each subsystem area using a time-phased, goal oriented approach that provides critical space access capabilities in a timely manner and involves subsystem ground and flight demonstrations. This S&T plan addresses near-term (2009), mid-term (2016), and long-term (2025) goals and objectives for space access. In addition, system engineering and integration approach was used to make sure that the plan addresses the requirements of the end users. This paper describes in some detail the technologies in NAI-Space Access pillar. Some areas of emphasis are: high temperature materials, thermal protection systems, long life, lightweight, highly efficient airframes, metallic and composite cryotanks, advanced liquid rocket engines, integrated vehicle health monitoring and management, highly operable systems and payloads. Implementation strategies for NAI are also described.

Culbertson, Andrew↗
NASA NTRS1985

A thick Anger camera for gamma-ray astronomy

The NaI(Tl) Anger camera is a natural candidate for a position sensitive detector in imaging of astrophysical gamma-ray sources. Here laboratory measurements are presented of the response of a relatively thick (5.1 cm) NaI(Tl) Anger camera designed for coded aperture imaging in the 50 keV to 2 MeV energy range. A position resolution of 10.5 mm FWHM at 122 keV and 6.3 mm FWHM at 662 keV. The energy resolution was 7 percent FWHM at 662 keV. The ability of the detector to resolve the depth of the gamma-ray interaction and the use of this depth resolution to reduce back-incident and internal background is discussed.

Cook, W. R.↗
NASA NTRS2009

Overview of the Turbine Based Combined Cycle Discipline

The NASA Fundamental Aeronautics Hypersonics project is focused on technologies for combined cycle, airbreathing propulsions systems to enable reusable launch systems for access to space. Turbine Based Combined Cycle (TBCC) propulsion systems offer specific impulse (Isp) improvements over rocket-based propulsion systems in the subsonic takeoff and return mission segments and offer improved safety. The potential to realize more aircraft-like operations with expanded launch site capability and reduced system maintenance are additional benefits. The most critical TBCC enabling technologies as identified in the National Aeronautics Institute (NAI) study were: 1) mode transition from the low speed propulsion system to the high speed propulsion system, 2) high Mach turbine engine development, 3) transonic aero-propulsion performance, 4) low-Mach-number dual-mode scramjet operation, 5) innovative 3-D flowpath concepts and 6) innovative turbine based combined cycle integration. To address several of these key TBCC challenges, NASA s Hypersonics project (TBCC Discipline) initiated an experimental mode transition task that includes an analytic research endeavor to assess the state-of-the-art of propulsion system performance and design codes. This initiative includes inlet fluid and turbine performance codes and engineering-level algorithms. This effort has been focused on the Combined Cycle Engine Large-Scale Inlet Mode Transition Experiment (CCE LIMX) which is a fully integrated TBCC propulsion system with flow path sizing consistent with previous NASA and DoD proposed Hypersonic experimental flight test plans. This experiment is being tested in the NASA-GRC 10 x 10 Supersonic Wind Tunnel (SWT) Facility. The goal of this activity is to address key hypersonic combined-cycle-engine issues: (1) dual integrated inlet operability and performance issues unstart constraints, distortion constraints, bleed requirements, controls, and operability margins, (2) mode-transition constraints imposed by the turbine and the ramjet/scramjet flow paths (imposed variable geometry requirements), (3) turbine engine transients (and associated time scales) during transition, (4) high-altitude turbine engine re-light, and (5) the operating constraints of a Mach 3-7 combustor (specific to the TBCC). The model will be tested in several test phases to develop a unique TBCC database to assess and validate design and analysis tools and address operability, integration, and interaction issues for this class of advanced propulsion systems. The test article and all support equipment is complete and available at the facility. The test article installation and facility build-up in preparation for the inlet performance and operability characterization is near completion and testing is planned to commence in FY11.

Thomas, Scott R.↗
NASA NTRS2005

Astrobiology at Arizona State University: An Overview of Accomplishments

During our five years as an NAI charter member, Arizona State University sponsored a broadly-based program of research and training in Astrobiology to address the origin, evolution and distribution of life in the Solar System. With such a large, diverse and active team, it is not possible in a reasonable space, to cover all details of progress made over the entire five years. The following paragraphs provide an overview update of the specific research areas pursued by the Arizona State University (ASU) Astrobiology team at the end of Year 5 and at the end of the 4 month and subsequent no cost month extensions. for a more detailed review, the reader is referred to the individual annual reports (and Executive Summaries) submitted to the NAI at the end of each of our five years of membership. Appended in electronic form is our complete publication record for all five years, plus a tabulation of undergraduates, graduate students and post-docs supported by our program during this time. The overarching theme of ASU s Astrobiology program was "Exploring the Living Universe: Studies of the Origin, Evolution and Distribution of Life in the Solar System". The NAi-funded research effort was organized under three basic sub- themes: 1. Origins of the Basic Building Blocks of Life. 2. Early Biosphere Evolution. and 3. Exploring for Life in the Solar System. These sub-theme areas were in turn, subdivided into Co-lead research modules. In the paragraphs that follow, accomplishments for individual research modules are briefly outlined, and the key participants presented in tabular form. As noted, publications for each module are appended in hard copy and digital formats, under the name(s) of lead co-Is.

Farmer, Jack↗
NASA NTRS1985

Monte Carlo simulation of a new gamma ray telescope

A new Monte Carlo code has been written to simulate the response of the new University of California double scatter gamma ray telescope. This package of modular software routines, written in VAX FORTRAN 77 simulates the detection of 0.1 to 35 MeV gamma rays. The new telescope is flown from high altitude balloons to measure medium energy gamma radiation from astronomical sources. This paper presents (1) the basic physics methods in the code, and (2) the predicted response functions of the telescope. Gamma ray processes include Compton scattering, pair production and photoelectric absorption in plastic scintillator, NaI(Tl) and aluminum. Electron transport processes include ionization energy loss, multiple scattering, production of bremsstrahlung photons and positron annihilation.

Simone, J.↗
NASA NTRS1985

A Cerenkov-delta E-Cerenkov detector for high energy cosmic ray isotopes and an accelerator study of Ar-40 and Fe-56 fragmentation

A high energy cosmic ray detector--the High Energy Isotope Spectrometer Telescope (HEIST) is described. It is a large area (0.25 m(swp 2) SR) balloon borne isotope spectrometer designed to make high resolution measurements of isotopes in the element range from neon to nickel (10 Z 28) at energies of about 2 GeV/nucleon. HEIST determines the mass of individual nuclei by measuring both the change in the Lorentz factor (delta gamma) that results from traversing the NaI stack, and the energy loss (delta E) in the stack. Since the total energy of an isotope is given by E = (gamma M), the mass M can be determined by M = delta E/delta, gamma. The instrument is designed to achieve a typical mass resolution of 0.2 amu. The isotopic composition of the fragments from the breakup of high energy An-40 and Fe-56 nuclei are measured experimentally. Isotope yields are compared with calculated yields based on semi-empirical cross-section formulae.

Lau, K. H.↗
NASA NTRS1989

Solar flare X-ray polarimeter utilizing a large area thin beryllium scattering disk

A model of a solar flare X-ray polarimeter utilizing a large-area thin beryllium scattering disk was developed using Monte Carlo techniques for several classes of solar flares. The solar-flare polarimeter consists of a 30-cm-diam Be disk of about 1/3 of a scattering length thickness, which is surrounded by a cylindrical detector composed of six segmented panels of NaI scintillators, each coupled to 15 photomultiplier tubes. The instrument is sensitive to X-rays from 10 to 100 keV. For a class-M-2 solar flare observed for 10 sec from a balloon at an altitude of 150,000 ft, the minimum detectable polarization at the 99 percent statistical confidence level was found to be 1-6 percent over the energy range 20-100 keV.

Gotthelf, E.↗
NASA NTRS1978

A hard X-ray and gamma ray observation of the 22 November 1977 solar flare

The Franco-Soviet experiment package Signe 2 MP for solar and cosmic X and gamma ray observations, launched aboard a Soviet Prognoz satellite into a highly eccentric earth orbit is described. An uncollimated NaI detector 37 mm thick by 90 mm diameter, placed on the upper surface of the satellite faced the sun. A collimated lateral NaI detector 14 mm thick by 38 mm diameter also faced the sun, and a similar lateral detector faced the anti-solar direction. Data tapes reveal an intense solar flare up to energies of up to 5 MeV, with evidence for line emission at 2.23 MeV and possibly 4.4 MeV. The event observed was associated with the Mc Math Plage Region 15031, and an H-alpha flare of importance 2B. It is not yet clear what radio emission is associated with the X-ray observation.

Chambon, G.↗
NASA NTRS1992

Observation of gamma ray bursts and flares by the EGRET telescope on the Compton Gamma Ray Observatory

The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory has observed energetic gamma ray bursts and flares. On May 3, 1991, EGRET detected a gamma ray burst both in the energy measuring NaI (Tl) scintillator and independently in the spark chamber imaging assembly. The NaI spectra were accumulated by a special BURST mode of EGRET. The spectra were measured over a range from 1 to 200 MeV, in three sequential spectra of 1,2, and 4 seconds. During the peak of the burst, six individual gamma rays were detected in the spark chamber, allowing a determination of the burst arrival direction. The intense flares of June were also detected. A solar flare on June 4 was observed to last for several minutes and for a brief time, less than a minute, had significant emission of gamma rays exceeding 150 MeV.

Schneid, E. J.↗