Search NASA⌕ Search

SEARCH · Search NASA

Results for “ultra”

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

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

At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Ultra high resolution images of the solar chromosphere and corona using coordinated rocket and balloon observations

A discussion is presented of the scientific objectives that can be pursued by simultaneous coronal/chromospheric observation with the Multi-Spectral Solar Telescope Array (MSSTA), and a new balloon-borne observatory called the Ultra-High Resolution Vacuum Ultraviolet Spectroheliograph (UHRVS). Attention is given to the proposed UHRVS observatory, which will incorporate two instruments, a 65-cm aperture telescope with narrowband filters for high resolution photographic and photoelectric spectroheliograms, and a very high resolution spectrograph which uses a 40-cm aperture telescope. The capabilities of the MSSTA, and the joint UHRVS/MSSTA observing program that is envisioned are reviewed.

Walker, Arthur B. C., Jr.↗
NASA NTRS1992

The Ultra High Resolution XUV Spectroheliograph. III - A modified configuration for a free flying platform

The Ultra-High Resolution XUV Spectroheliograph (UHRXS) is a comprehensive solar observatory capable of studying solar phenomena at soft X-ray, XUV, EUV, and VUV wavelengths with normal incidence imaging multilayer telescopes capable of very high angular resolution (about 0.1 arcsec), and spectrographs able to achieve high spectral resolution. This instrument has been selected by NASA for flight as an attached payload on the Space Station Freedom. Recent developments have made it clear that accommodations for attached payloads on Freedom will not become available during the initial operations of Freedom and may never be available. We have studied the changes that must be made to place the UHRXS instrument on a Free Flying Plafform such as the Delta Launched Explorer Bus. We report on the configuration, performance, and accommodation on a free flying platform of the revised UHRXS concept.

Walker, Arthur B. C., Jr.↗
NASA NTRS1945

Effect of Maximum Cruise-power Operation at Ultra-lean Mixture and Increased Spark Advance on the Mechanical Condition of Cylinder Components

A continuous 50-hour test was conducted to determine the effect of maximum cruise-power operation at ultra-lean fuel-air mixture and increased spark advance on the mechanical conditions of cylinder components. The test was conducted on a nine-cylinder air-cooled radial engine at the following conditions:brake horsepower, 750; engine speed, 1900 rpm; brake mean effective pressure, 172 pounds per square inch; fuel-air ratio, 0.052; spark advance, 30 deg B.T.C.; and maximum rear-spark-plug-bushing temperature, 400 F. In addition to the data on corrosion and wear, data are presented and briefly discussed on the effect of engine operation at the conditions of this test on economy, knock, preignition, and mixture distribution. Cylinder, piston, and piston-ring wear was small and all cylinder component were in good condition at the conclusion of the 50-hour test except that all exhaust-valve guides were bellmouthed beyond the Army's specified limit and one exhaust-valve face was lightly burned. It is improbable that the light burning in one spot of the valve face would have progressed further because the burn was filled with a hard deposit so that the valve face formed an unbroken seal and the mating seat showed no evidence of burning. The bellmouthing of the exhaust-valve guides is believed to have been a result of the heavy carbon and lead-oxide deposits, which were present on the head end of the guided length of the exhaust-valve stem. Engine operational the conditions of this test was shown to result In a fuel saving of 16.8 percent on a cooled-power basis as compared with operation at the conditions recommended for this engine by the Army Air Forces for the same power.

ENGINE CYLINDERS-WEAR↗
NASA NTRS1993

Status of local oscillators for operating ultra-high resolution frequency discriminators as frequency standards

The operation of new improved frequency standards based on new ultra-high-resolution frequency discriminators requires high stability local, or 'flywheel' oscillators. We review the spectral density of phase fluctuations of existing flywheel oscillators and the related time domain frequency stability of new and proposed cryogenically cooled oscillators suitable for this application. Presently used devices include the quartz crystal oscillator, the room-temperature actively oscillating atomic hydrogen (H) maser, and the superconducting maser oscillator. Future devices include the cryogenic H-maser and other cryogenic devices using resonators of superconducting metal or solid crystalline sapphire. The relation of the phase spectral density of these devices to the characteristics of present and proposed frequency discriminators based on trapped cooled ions and cold atoms is discussed in terms of their operation as frequency standards.

Vessot, R. F. C.↗
NASA NTRS1993

Fabrication of very-low-density, high-stiffness carbon fiber/aluminum hybridized composite with ultra-low density and high stiffness (M-11)

Fabrication of a composite material with ultra-low density and high stiffness in microgravity is the objective of the investigation. The composite structure to be obtained is a random three-dimensional array of high modulus, short carbon fibers bonded at contact points by an aluminum alloy coated on the fibers. The material is highly porous and thus has a very low density. The motivation toward the investigation, simulation experiments, choice of the component materials, and on-flight experiment during ballistic trajectory of a NASDA rocket, are described.

Suzuki, Tomoo↗
NASA NTRS1995

Early results from the ultra heavy cosmic ray experiment

Data extraction and analysis of the LDEF Ultra Heavy Cosmic Ray Experiment is continuing. Almost twice the pre LDEF world sample has been investigated and some details of the charge spectrum in the region from Z approximately 70 up to and including the actinides are presented. The early results indicate r process enhancement over solar system source abundances.

Osullivan, D.↗
NASA NTRS1995

Ultra-high pressure water jetting for coating removal and surface preparation

This paper shall examine the basics of water technology with particular attention paid to systems currently in use and some select new applications. By providing an overview of commercially available water jet systems in the context of recent case histories, potential users may evaluate the process for future applications. With the on going introduction of regulations prohibiting the use of chemical paint strippers, manual scrapping and dry abrasive media blasting, the need for an environmentally compliant coating removal process has been mandated. Water jet cleaning has been a traditional part of many industrial processed for year, although it has only been in the last few years that reliable pumping equipment capable of ultra-high pressure operation have become available. With the advent of water jet pumping equipment capable of sustaining pressures in excess of 36,000 psi. there has been shift away from lower pressure, high water volume systems. One of the major factors in driving industry to seek higher pressures is the ability to offer higher productivity rates while lowering the quantity of water used and subsequently reprocessed. Among benefits of the trend toward higher pressure/lower volume systems is the corresponding reduction in water jet reaction forces making hand held water jetting practical and safe. Other unique applications made possible by these new generation pumping systems include the use of alternative fluids including liquid ammonia for specialized and hazardous material removal applications. A review of the equipment used and the required modifications will be presented along with the conclusions reached reached during this test program.

Johnson, Spencer T.↗
NASA NTRS1995

A process for preparing an ultra-thin, adhesiveless, multi-layered, patterned polymer substrate

A process for preparing an ultra-thin, adhesiveless, multi-layered, patterned polymer substrate is disclosed. The process may be used to prepare both rigid and flexible cables and circuit boards. A substrate is provided and a polymeric solution comprising a self-bonding, soluble polymer and a solvent is applied to the substrate. Next, the polymer solution is dried to form a polymer coated substrate. The polymer coated substrate is metallized and patterned. At least one additional coating of the polymeric solution is applied to the metallized, patterned, polymer coated substrate and the steps of metallizing and patterning are repeated. Lastly, a cover coat is applied. When preparing a flexible cable and flexible circuit board, the polymer coating is removed from the substrate.

Bryant, Robert G.↗
NASA NTRS1996

Ultra Small Aperture Terminal: System Design and Test Results

The Ultra Small Aperture Terminal (USAT) has been developed to test and demonstrate remote and broadcast satcom applications via the Advanced Communications Technology Satellite (ACTS). The design of these ground stations emphasize small size, low power consumption, portable and rugged terminals. Each ground station includes several custom design parts such as 35 cm diameter antenna, 1/4 Watt transmitter with built-in upconverter, and 4.0 dB Noise Figure (NF) receiver with built-in downconverter. In addition, state-of-the-art commercial parts such as highly stable ovenized crystal oscillators and dielectric resonator oscillators are used in the ground station design. Presented in this paper are system level design description, performance, and sample applications.

Sohn, Philip Y.↗
NASA NTRS1995

High-Performance electronics at ultra-low power consumption for space applications: From superconductor to nanoscale semiconductor technology

A detailed review of Sandia's work in ultralow power dissipation electronics for space flight applications, including superconductive electronics, new advances in quantum well structures, and ultra-high purity 3-5 materials, and recent advances in micro-electro-optical-mechanical systems (MEMS) is presented. The superconductive electronics and micromechanical devices are well suited for application in micro-robotics, micro-rocket engines, and advanced sensors.

Duncan, Robert V.↗
NASA NTRS1997

Ultra Small Aperture Terminal for Ka-Band SATCOM

An ultra small aperture terminal (USAT) at Ka-band frequency has been developed by Lewis Research Center (LeRC) for data rates up to 1.5 Mbps in the transmit mode and 40 Mbps in receive mode. The terminal consists of a 35 cm diameter offset-fed parabolic antenna which is attached to a solid state power amplifier and low noise amplifier. A single down converter is used to convert the Ka-band frequency to 70 MHz intermediate frequency (IF). A variable rate (9.6 Kbps to 10 Mbps) commercial modem with a standard RS-449/RS-232 interface is used to provide point-to-point digital services. The terminal has been demonstrated numerous times using the Advanced Communications Technology Satellite (ACTS) and the 4.5 in Link Evaluation Terminal (LET) in Cleveland. A conceptual design for an advanced terminal has also been developed. This advanced USAT utilizes Microwave Monolithic Integrated Circuit (MMIC) and flat plate array technologies. This terminal will be self contained in a single package which will include a 1 watt solid state amplifier (SSPA), low noise amplifier (LNA) and a modem card located behind the aperture of the array. The advanced USAT will be light weight, transportable, low cost and easy to point to the satellite. This paper will introduce designs for the reflector based and array based USAT's.

Acosta, Roberto↗
NASA NTRS1997

Trends in Performance and Characteristics of Ultra-Stable Oscillators for Deep Space Radio Science Experiments

Telecommunication systems of spacecraft on deep space missions also function as instruments for Radio Science experiments. Radio scientists utilize the telecommunication links between spacecraft and Earth to examine very small changes in the phase/frequency, amplitude, and/or polarization of radio signals to investigate a host of physical phenomena in the solar system. Several missions augmented the radio communication system with an Ultra-Stable Oscillator (USO) in order to provide a highly stable reference signal for oneway downlink. This configuration is used in order to enable better investigations of the atmospheres of the planets occulting the line-of-sight to the spacecraft; one-way communication was required and the transponders' built-in auxiliary oscillators were neither sufficiently stable nor spectrally pure for the occultation experiments. Since Radio Science instrumentation is distributed between the spacecraft and the ground stations, the Deep Space Network (DSN) is also equipped to function as a world-class instrument for Radio Science research. For a detailed account of Radio Science experiments, methodology, key discoveries, and the DSN's historical contribution to the field, see Asmar and Renzetti (1993). The tools of Radio Science can be and have also been utilized in addressing several mission engineering challenges; e.g., characterization of spacecraft nutation and anomalous motion, antenna calibrations, and communications during surface landing phases. Since the first quartz USO was flown on Voyager, the technology has advanced significantly, affording future missions higher sensitivity in reconstructing the temperature pressure profiles of the atmospheres under study as well as other physical phenomena of interest to Radio Science. This paper surveys the trends in stability and spectral purity performance, design characteristics including size and mass, as well as cost and history of these clocks in space.

Asmar, Sami↗
NASA NTRS1997

Rubidium Ultra-Stable Oscillators at Titan: The Huygens Doppler Wind Experiment

The Doppler Wind Experiment (DWE) is one of six investigations to be performed during the Titan atmospheric descent of the ESA Huygens Probe. The primary scientific objective is to measure the direction and strength of Titan's zonal winds with an accuracy better than 1 m/s. The Probe's wind-induced horizontal motion will be derived from the residual Doppler shift of its S-band radio link to the Cassini Orbiter, corrected for all known orbit and propagation effects, from the beginning of the mission (altitude: approx. 160 km) down to impact on the surface. The DWE Instrumentation consists of Rb-based Ultra-Stable Oscillators used to: (1) generate the transmitted signal from the Probe and (2) extract the frequency of the received signal on the Orbiter. The capabilities of these USOs under the rugged experimental conditions on Titan and some results from the DWE pre-launch test program are described.

Bird, M. K.↗
NASA NTRS1998

X-Ray Spectral and Temporal Studies of the Ultra-Compact System X1916-05

Rossi x-ray timing Explorer (RXTE) Cycle 1 data on the ultra-compact low mass x- ray binary (LMXB) X1916-05 is analyzed. In this current report, the scientific objectives of this investigation of hard x-ray studies of bursters and the results achieved are summarized. The scientific objectives are: (1) Period of the x-ray dips in X1916-05; (2) Phase stability of the x-ray dip period; (3) Spectral break energy and its dependence on mass transfer rate; and (4) Qpos detected from this LMXB. A list of published papers resulted from this project is also included.

Grindlay, Jonathan E.↗
NASA NTRS1998

Imaging Extra-Solar Planets with an Ultra-Large Space Telescope

NASA's Origins Program is directed toward two main goals: Imaging of galactic evolution in the early universe, and searching for planets orbiting nearby stars. The Next-Generation Space Telescope (NGST), operating at low temperature with an 8-m aperture, is well designed to meet the first goal. The goal of imaging planets orbiting nearby stars is more problematic. One line of investigation has been the ULTIMA concept (Ultra-Large Telescope, Integrated Missions in Astronomy). In this report, I will lay out the resolution requirements for telescopes to achieve the imaging of extrasolar planets, and describe a modeling tool created to investigate the requirements for imaging a planet when it is very near a much brighter star.

Taylor, Charles R.↗
NASA NTRS1999

Demonstration of an Ultra-Short Channel Metal Monolith Catalytic Reactor for Trace Contaminant Control Applications

The International Space Station (ISS) Trace Contaminant Control Subassembly (TCCS) design is based upon proven, highly reliable technology. However, because its core unit operations rely upon expendable activated charcoal and an indirectly heated high temperature catalyst, annual logistics mass, crew time, and power consumption requirements are significant. To address this situation, a unique catalytic reactor design has been developed which is suitable for retrofit into the TCCS's high temperature catalytic oxidizer (HTCO) assembly. The unique design, which employs a metallic, ultra-short channel length monolith (USCM) catalyst substrate, was tested in a flight-like TCCS HTCO assembly to investigate its performance characteristics. Test results indicate that retrofitting the TCCS with a USCM-based catalytic reactor is feasible and that it may provide significant reductions in logistics mass, crew time, and power consumption. Savings indicated by test results are up to 81% for annual logistics, 56% for crew time, and 77% for startup transient duration. In addition, its demonstrated ability to operate in a power saving mode provides up to a 43% savings in average power consumption. A summary of the USCM demonstration test objectives, approach, results, and specific benefits to the TCCS's process economics are presented,

Perry, J. L↗