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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
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

COBE diffuse infrared background experiment observations of the galactic bulge

Low angular resolution maps of the Galactic bulge at 1.25, 2.2, 3.5, and 4.9 micrometers obtained by the Diffuse Infrared Background Experiment (DIRBE) onboard NASA's Cosmic Background Explorer (COBE) are presented. After correction for extinction and subtraction of an empirical model for the Galactic disk, the surface brightness distribution of the bulge resembles a flattened ellipse with a minor-to-major axis ratio of approximately 0.6. The bulge minor axis scale height is found to be 2.1 deg +/- 0.2 deg for all four near-infrared wavelengths. Asymmetries in the longitudinal distribution of bulge brightness contours are qualitatively consistent with those expected for a triaxial bar with its near end in the first Galactic quadrant (0 deg less than l less than 90 deg). There is no evidence for an out-of-plane tilt of such a bar.

Weiland, J. L.↗
NASA NTRS1991

The X-ray Timing Explorer

The capabilities and projected mission objectives of the X-ray Timing Explorer (XTE) are set forth with attention given to the components of the space explorer. The XTE instrument complement is reviewed and specific data and graphic descriptions are presented regarding the large-area proportional counter array, the all-sky monitor, and the high-energy crystal scintillation experiment. The XTE provides low-background continuous 2-200 keV response with large apertures, rapid maneuverability, and detailed energy-resolved studies of phenomena close to neutron stars. The synergism of the mission capabilities is shown to permit a powerful mechanism for timing and broad-band spectral studies after deployment by the NASA Explorer Platform in approximately 1995.

Bradt, H. V.↗
NASA NTRS2013

A Comparison between High-Energy Radiation Background Models and SPENVIS Trapped-Particle Radiation Models

We have been assessing the effects of background radiation in low-Earth orbit for the next generation of X-ray and Cosmic-ray experiments, in particular for International Space Station orbit. Outside the areas of high fluxes of trapped radiation, we have been using parameterizations developed by the Fermi team to quantify the high-energy induced background. For the low-energy background, we have been using the AE8 and AP8 SPENVIS models to determine the orbit fractions where the fluxes of trapped particles are too high to allow for useful operation of the experiment. One area we are investigating is how the fluxes of SPENVIS predictions at higher energies match the fluxes at the low-energy end of our parameterizations. I will summarize our methodology for background determination from the various sources of cosmogenic and terrestrial radiation and how these compare to SPENVIS predictions in overlapping energy ranges.

high-energy radiation↗
NASA NTRS1988

On the need for space tests of plasma contactors as electron collectors

An analysis is presented of laboratory experiments that have shown that hollow plasma sources can provide low-impedance contact with a background plasma. In particular, some experiments show an report an 'ignited mode' of electron collection using plasma sources where almost an ampere was collected at a potential of 100 volts. The experimental results are compared with theoretical and computational models of plasma layers. Preliminary results indicate that the measured potential profiles and collected currents during the 'ignited mode' correspond to an increase in the background plasma thermal current of more than an order of magnitude. The results imply that the 'ignited mode' results are substantially impacted by the laboratory electron source and the tank size. Only experiments performed in space will be able to provide the correct boundary conditions for reliably testing high electron collection by plasma contactors.

Katz, Ira↗
NASA NTRS2004

Applied Superconductivity and Superfluidity for Exploration of the Moon and Mars

The initiative for human exploration of the Moon and Mars presents great technical challenges as well as new opportunities for scientific investigations. I will discuss recent developments in superconductivity and superfluidity that can be applied to solve some of these technical challenges. This includes biomedical imaging of astronauts using an array of SQUID magnetometers; resource exploration using SQUID as well as a SQUID-based gravitational gradiometer; measurement of rotational jitter of the Moon and of Mars, for improvement in GPS using a superfluid gyroscope; and the concept of a high precision superfluid clock recently proposed for navigation at JPL. Physicists can also participate as explorers in the Moon/Mars initiative. I will discuss a proposed experiment to search for the postulated strangelet particle (a dark matter candidate) by using the Moon or Mars as a giant detector. As suggest by Nobel Laureate Sheldon Glashow, a massive (approx. 1 ton) strangelet can generate a trail of seismic waves, as it traverses a celestial body. The pristine environments of the Moon and Mars, with their very low seismic backgrounds, are ideal for such an experiment. Very sensitive SQUID-based seismometers can be deployed to increase the sensitivity of strangelet detection.

Chui, Talso↗
NASA NTRS2003

STS-107 Flight Day 8 Highlights

This video shows the activities of the STS-107 crew (Rick Husband, Commander; William McCool, Pilot; Kalpana Chawla, David Brown, Michael Anderson, Laurel Clark, Mission Specialists, Ilan Ramon, Payload Specialist) during flight day 8 of the Columbia orbiter's final flight. The primary activities of flight day 8 are spaceborne experiments. Some background information is given on the SOFBALL (Structure of Flame Balls at Low Lewis-Number) microgravity experiment as footage of the flame balls is shown. The video also shows the MEIDEX (Mediterranean Israeli Dust Experiment) calibrating on the Moon. The six STARS (Space Technology and Research Students) international student experiments are profiled, including experiments on carpenter bees (Liechtenstein), spiders (Australia), silkworms (China), ants (United States), crystal growth (Israel), and fish embryos (Japan). A commercial experiment on roses is also profiled. Astronaut Clark gives a tour of the SpaceHab RDM (Research Double Module), in the space shuttle's payload bay. Astronauts McCool and Ramon take turns on an exercise machine. The video includes a partly cloudy view of the Pacific Ocean.

Source record↗
NASA NTRS1976

Optical technique for measurement of random water wave surfaces

An optical system using the refraction of a vertical light ray has been developed for measuring the slope of random wind-generated water waves. The basic elements of the system are photovoltaic cells which are connected to individual amplifiers so that when the refracted light beam is incident on a cell, the output of the cell is amplified and then supplied as input to a comparator. The comparator then provides a specified voltage output, independent of the incident light intensity, as long as it is above a designated background value. The comparators are designed to give output voltages comparable with standard TTL. This arrangement provides a high signal from the cell when it experiences incident light, and a low signal when there is only background light, with the high and low signals at TTL voltage levels.

Sorrell, F. Y.↗
NASA NTRS1992

The soft X-ray diffuse background observed with the HEAO 1 low-energy detectors

Results of a study of the diffuse soft-X-ray background as observed by the low-energy detectors of the A-2 experiment aboard the HEAO 1 satellite are reported. The observed sky intensities are presented as maps of the diffuse X-ray background sky in several energy bands covering the energy range 0.15-2.8 keV. It is found that the soft X-ray diffuse background (SXDB) between 1.5 and 2.8 keV, assuming a power law form with photon number index 1.4, has a normalization constant of 10.5 +/- 1.0 photons/sq cm s sr keV. Below 1.5 keV the spectrum of the SXDB exceeds the extrapolation of this power law. The low-energy excess for the NEP can be fitted with emission from a two-temperature equilibrium plasma model with the temperatures given by log I1 = 6.16 and log T2 = 6.33. It is found that this model is able to account for the spectrum below 1 keV, but fails to yield the observed Galactic latitude variation.

Garmire, G. P.↗
NASA NTRS1988

Scientific investigations at a lunar base

Scientific investigations to be carried out at a lunar base can have significant impact on the location, extent, and complexity of lunar surface facilities. Among the potential research activities to be carried out are: (1) Lunar Science: Studies of the origin and history of the Moon and early solar system, based on lunar field investigations, operation of networks of seismic and other instruments, and collection and analysis of materials; (2) Space Plasma Physics: Studies of the time variation of the charged particles of the solar wind, solar flares and cosmic rays that impact the Moon as it moves in and out of the magnetotail of the Earth; (3) Astronomy: Utilizing the lunar environment and stability of the surface to emplace arrays of astronomical instruments across the electromagnetic spectrum to improve spectral and spatial resolution by several orders of magnitude beyond the Hubble Space Telescope and other space observatories; (4) Fundamental physics and chemistry: Research that takes advantage of the lunar environment, such as high vacuum, low magnetic field, and thermal properties to carry out new investigations in chemistry and physics. This includes material sciences and applications; (5) Life Sciences: Experiments, such as those that require extreme isolation, highly sterile conditions, or very low natural background of organic materials may be possible; and (6) Lunar environmental science: Because many of the experiments proposed for the lunar surface depend on the special environment of the Moon, it will be necessary to understand the mechanisms that are active and which determine the major aspects of that environment, particularly the maintenance of high-vacuum conditions. From a large range of experiments, investigations and facilities that have been suggested, three specific classes of investigations are described in greater detail to show how site selection and base complexity may be affected: (1) Extended geological investigation of a complex region up to 250 kilometers from the base requires long range mobility, with transportable life support systems and laboratory facilities for the analysis of rocks and soil. Selection of an optimum base site would depend heavily on an evaluation of the degree to which science objectives could be met. These objectives could include lunar cratering, volcanism, resource surveys or other investigations; (2) An astronomical observatory initially instrumented with a VLF radio telescope, but later expanding to include other instruments, requires site preparation capability, "line shack" life support systems, instrument maintenance and storage facilities, and sortie mode transportation. A site perpetually shielded from Earth is optimum for the advanced stages of a lunar observatory; (3) an experimental physics laboratory conducting studies requiring high vacuum facilities and heavily instrumented experiments, is not highly dependent on lunar location, but will require much more flexibility in experiment operation and EVA capability, and more sophisticated instrument maintenance and fabrication facilities.

Extraterrestrial Environment↗
NASA NTRS1990

Some comparisons of linear stability theory with experiment at supersonic and hypersonic speed

Measurements of waves initiated by wind-tunnel sounds are obtained for both supersonic and hypersonic speed. Flat-plate experiments carried out at Mach numbers of 4.5, 3.7, and 2.4 under the condition of laminar tunnel-wall boundary layers whereby a low background fluctuation level prevailed are outlined, as well as flat-plate experiments with sound-induced waves at supersonic speeds. Experimental studies of 'natural' wave growth on sharp cones at zero angle of attack and Mach numbers near 8 are discussed. Attention is focused on experimental research needed on boundary-layer receptivity to eddy Mach-wave radiation, hypersonic speed, and the stability-transition relationship in zero-pressure-gradient layers.

Kendall, James M., Jr.↗
NASA NTRS2003

The Interaction of Positively-charged Ions with Nucleic Acid Systems

The successful development of extremely low background sample cells for x-ray scattering studies has enabled experiments designed to elucidate some of the fundamental physical interactions involved in macromolecular folding. Microfabrication techniques were used to fabricate low volume (50 micro-liter) sample cells with silicon nitride membranes (sub micron in thickness) as x-ray windows. Scientifically, these studies focus on the interaction of negatively charged nucleic acid systems, RNA and DNA, with their surrounding (positively charged) ion atmospheres. Understanding the structure of the ion atmosphere and its influence on the shape/conformation of the macromolecule will help reveal the underlying physical forces employed by nature in the self-assembly of these important molecules.

Pollack, Lois↗
NASA NTRS2017

Ballooning for Biologists: Mission Essentials for Flying Experiments on Large NASA Balloons

Despite centuries of scientific balloon flights, only a handful of experiments have produced biologically-relevant results. Yet unlike orbital spaceflight, it is much faster and cheaper to conduct biology research with balloons, sending specimens to the near space environment of Earths stratosphere. Samples can be loaded the morning of a launch and sometimes returned to the laboratory within one day after flying. The National Aeronautics and Space Administration (NASA) flies large, unmanned scientific balloons from all over the globe, with missions ranging from hours to weeks in duration. A payload in the middle portion of the stratosphere (approx. 35 km above sea level) will be exposed to an environment similar to the surface of Mars: temperatures generally around -36 C, atmospheric pressure at a thin 1 kPa, relative humidity levels <1%, and a harsh illumination of ultraviolet (UV) and cosmic radiation levels (about 100 W/sq m and 0.1 mGy/d, respectively) that can be obtained nowhere else on the surface of the Earth, including environmental chambers and particle accelerator facilities attempting to simulate space radiation effects. Considering the operational advantages of ballooning and the fidelity of space-like stressors in the stratosphere, researchers in aerobiology, astrobiology, and space biology can benefit from balloon flight experiments as an intermediary step on the extraterrestrial continuum (ground, low Earth orbit, and deep space studies). Our presentation targets biologists with no background or experience in scientific ballooning. We will provide an overview of large balloon operations, biology topics that can be uniquely addressed in the stratosphere, and a roadmap for developing payloads to fly with NASA.

Smith, David J.↗
NASA NTRS2020

Ballooning for Biologists: Mission Essentials for Flying Life Science Experiments to Near Space

Despite centuries of scientific balloon flights, only a handful of experiments have produced biologically-relevant results. Yet unlike orbital spaceflight, it is much faster and cheaper to conduct biology research with balloons, sending specimens to the near space environment of Earth’s stratosphere. Samples can be loaded the morning of a launch and sometimes returned to the laboratory within one day. The National Aeronautics and Space Administration (NASA) flies large, unmanned scientific balloons from all over globe, with missions ranging from hours to weeks in duration. A payload in the middle portion of the stratosphere (~35 km above sea level) will be exposed to an environment similar to the surface of Mars: temperatures as cold as -100 °C, atmospheric pressure at a thin 0.9 kPa, relative humidity levels < 1%, and a harsh illumination of ultraviolet (UV) and cosmic radiation levels (about 100 W/m 2 and 0.07 mGy/d, respectively) that can be obtained nowhere else on the surface of the Earth, including environmental chambers and particle accelerator facilities attempting to simulate space radiation effects. Considering operational advantages of ballooning and the fidelity of space-like stressors in the stratosphere, researchers in aerobiology, astrobiology, and space biology can benefit from balloon flight experiments as an intermediary step on the extraterrestrial continuum (ground, low Earth orbit, and deep space studies). Our review targets biologists with no background or experience in scientific ballooning. We will provide an overview of balloon operations, topics that can be uniquely addressed in the stratosphere, and a roadmap for developing payloads to fly with NASA.

NASA Balloon Program↗
NASA NTRS1989

Tests of the Rockwell Si:As Back-Illuminated Blocked-Impurity Band (BIBIB) detectors

Two arrays of Rockwell's Si:As back-illuminated blocked-impurity-band detectors were tested at the Max-Planck-Institute for Astronomy (MPIA) at low background and low temperature for possible use in the astronomical space experiment ISOPHOT. For these measurements special test equipment was put together. A cryostat was mechanically modified to accommodate the arrays and special peripheral electronics was added to a microprocessor system to drive the cold multiplexer and to acquire the output data. The first device, a 16x50 element array on a fan-out board was used to test individual pixels with a trans-impedance-amplifier at a photon background of 10(exp 8) Ph s(-1)cm(-2) and at temperatures of 2.7 to 4.4 K. The noise-equivalent-power NEP is in the range 5 - 7 x 10(exp -18) WHz(exp -1/2), the responsivity is less than or equal to 100 AW(exp -1)(f = 10 Hz). The second device was a 10x50 array including a cold readout electronics of switched FETs (SWIFET). Measurements of this array were done in a background range of 5 x 10(exp 5) to 5 x 10(exp 11) Ph s(exp-1)cm(exp-2) and at operating temperatures between 3.0 and 4.8 K. The NEP ranges from less than 10(exp -18) at the lowest background to 2 x 10(exp -16) WHz(exp -1/2) at the highest flux.

Wolf, J.↗
NASA NTRS1989

Flight worthy infrared bolometers with high throughput and low NEP

This paper describes the features of flight-worthy IR bolometers that were developed to meet the requirements of the Far Infrared Absolute Spectrometer (FIRAS) and the Diffuse Infrared Background Experiment (DIRBE) on the Cosmic Background Explorer of a short time constant, high throughput, and low noise equivalent power (NEP). The new bolometers use small chips of doped and compensated silicon as sensing elements, and diamond wafers coated with thin layers of Cr and Au as the absorbing substrate. The throughput values for the FIRAS bolometers and for DIRBE are 1.28 sr-sq cm, and 0.21 sr-sq cm, respectively. At 1.6, the time constants range from 3 to 40 ms, and their NEP range from 4 x 10 to the -15th to 1 x 10 to the -14th W/sq rt of Hz.

Serlemitsos, Aristides T.↗
NASA NTRS1981

NASA 3-Meter Infrared Telescope Facility at Mauna Kea

The demonstrated pointing, tracking and offsetting characteristics of the NASA 3-meter infrared telescope are reviewed. Other special features of the telescope such as low thermal background and versatile chopping secondary are also discussed. Experience is presented as to why these design features are important when making infrared observations of astronomical objects.

Becklin, E. E.↗
NASA NTRS1975

OSO-8 soft X-ray experiment (Wisconsin)

Information for operating and reducing data from the experiment which was designed to map low energy X-ray background emissions from 130 eV to 35 keV is presented. The detectors, counters, data system, and the gas system are discussed along with the functional operation of the subsystems. A command list indicating preconditions and resulting telemetry response for each command is included.

Source record↗
NASA NTRS1987

Transient heat transfer and thermophysical properties measurements in low gravity

Theoretical computer models and correlations which describe phenomena important in the design of transient heat transfer systems are verified and extended. Attention is given to heat transfer to a fluid near the thermodynamic critical point, i.e., a highly compressible fluid. The validity of the computer model is tested by conducting heat-transfer experiments in a low gravity environment where gravity-driven motion is essentially eliminated. It is noted that the NASA KC135 aircraft provides a useful low-g platform for experimental work and provides valuable experience and background for experiments ultimately designed to fly on the Space Shuttle.

Giarratano, P. J.↗