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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Digital Electronic Still Camera

Digital electronic still camera part of electronic recording, processing, tansmitting, and displaying system. Removable hard-disk drive in camera serves as digital electronic equivalent of photographic film. Images viewed, analyzed, or transmitted quickly. Camera takes images of nearly photographic quality and stores them in digital form. Portable, hand-held, battery-powered unit designed for scientific use. Camera used in conjunction with playback unit also serving as transmitting unit if images sent to remote station. Remote station equipped to store, process, and display images. Digital image data encoded with error-correcting code at playback/transmitting unit for error-free transmission to remote station.

Holland, Samuel D.↗
NASA NTRS1992

The NASA Electronic Still Camera system

The Electronic Still Camera (ESC) project has been implemented in its first form for space shuttle operations. The system is composed of three components: (1) a hand-held battery-operated fully digital and programmable high-resolution camera; (2) a laptop-computer-based playback/downlink unit for onboard image processing; and (3) a ground station capable of receiving shuttle data, processing images, producing hardcopies, and distributing the data and hardcopies to end users. The advantages of the ESC system over film and satellites are discussed, and system specifications are summarized.

Holland, S. D.↗
NASA NTRS2005

Why do Some Dwarf Novae Stand Still?

The papers published through support of NASA. "Why do Some DwarfNovae Stand Still?" Preliminary results were published in the form of an abstract as part of Joint Discussion 5, at the IAU meeting in Sydney. The complete reference is: Hartley, L. E., Long, K. S., Froning, C.-S., & Drew, J. E. 2003, "The White Dwarf and Accretion Stream in Z Cam", presented as part of Joint Discussion 5, "White Dwarfs: Galactic and Cosmologic Probes, at 25th meeting of the MU, Joint Discussion 5 , 16-17 July 2003, Sydney, Australia Our final results were published in the Astrophysical Journal this year. Hartley, L. E., Long, K. S., Froning, C. S., & Drew, J. E. 2005, "The Far-Ultraviolet Spectrum of Z Camelopardalis in Quiescence and Standstill", ApJ, 623,425.

Sonneborn, George↗
NASA NTRS2011

Foil X-Ray Mirrors for Astronomical Observations: Still an Evolving Technology

Foil X-ray mirrors, introduced by the Goddard X-ray Group in the late 1970s, were envisioned as an interim and complementary approach toward increased sensitivity for small inexpensive astronomical instruments. The extreme light weight nature of these mirrors dovetailed beautifully with Japan's small payload missions, leading to several collaborative, earth orbiting observatories, designed primarily for spectroscopy, of which SUZAKU is still in earth orbit. ASTRO-H is the latest joint instrument with Japan, presently in the implementation phase. At Goddard, some 30 years after we introduced them, we are involved with four separate flight instruments utilizing foil X-ray mirrors, a good indication that this technology is here to stay. Nevertheless, an improved spatial resolution will be the most welcomed development by all. The task of preparing upwards of 1000 reflectors, then assembling them into a single mirror with arcmin resolution remains a formidable one. Many, performance limiting approximations become necessary when converting commercial aluminum sheets into 8 quadrant segments, each with approximately 200 nested conical, approximately 4Angstrom surface reflectors, which are then assembled into a single mirror. In this paper we will describe the mirror we are presently involved with, slated for the Goddard high resolution imaging X-ray spectrometer (SXS) onboard ASTRO-H. Improved spatial resolution will be an important enhancement to the science objectives from this instrument. We are accordingly pursuing and will briefly describe in this paper several design and reflector assembly modifications, aimed toward that goal.

Serlemitsos, Peter J.↗
NASA NTRS2024

General Circulation Models Simulate Negative Liquid Water Path­–Droplet Number Correlations, but Anthropogenic Aerosols Still Increase Simulated Liquid Water Path

General circulation models' (GCMs) estimates of the liquid water path adjustment to anthropogenic aerosol emissions differ in sign from other lines of evidence. This reduces confidence in estimates of the effective radiative forcing of the climate by aerosol–cloud interactions (ERFaci). The discrepancy is thought to stem in part from GCMs' inability to represent the turbulence–microphysics interactions in cloud-top entrainment, a mechanism that leads to a reduction in liquid water in response to an anthropogenic increase in aerosols. In the real atmosphere, enhanced cloud-top entrainment is thought to be the dominant adjustment mechanism for liquid water path, weakening the overall ERFaci. We show that the latest generation of GCMs includes models that produce a negative correlation between the present-day cloud droplet number and liquid water path, a key piece of observational evidence supporting liquid water path reduction by anthropogenic aerosols and one that earlier-generation GCMs could not reproduce. However, even in GCMs with this negative correlation, the increase in anthropogenic aerosols from preindustrial to present-day values still leads to an increase in the simulated liquid water path due to the parameterized precipitation suppression mechanism. This adds to the evidence that correlations in the present-day climate are not necessarily causal. We investigate sources of confounding to explain the noncausal correlation between liquid water path and droplet number. These results are a reminder that assessments of climate parameters based on multiple lines of evidence must carefully consider the complementary strengths of different lines when the lines disagree.

General circulation models↗
NASA NTRS1973

A Quiet Engine for stilling complaints.

Two experimental Quiet Engines using derated CF6 cores are discussed. One engine has a low-speed fan running at a tip speed of 1160 fps; the other engine has a fan running at the high speed of 1550 fps. The two engines are expected to show the relative advantages of fans operating at low tip speeds with high lift coefficients in comparison with fans operating at high tip speeds with low lift coefficients. Test results obtained with full-scale (6-ft diameter) fans are examined.

Sanders, N. D.↗
NASA NTRS1981

SERT II thrusters - Still ticking after eleven years

The Space Electric Rocket Test II (SERT II) spacecraft was launched in 1970 with a primary objective of demonstrating long-term operation of a space electric thruster system. An overview is presented of all the SERT II testing conducted during the time from 1970 to 1981. Thruster testing and interaction results are considered, taking into account ion beam thrusting, distant neutralization, and the plasma beam thrust. In a discussion of durability testing, attention is given to the main cathodes, the neutralizer cathodes, the main keeper insulator, the H.V. grid insulators, the neutralizer propellant tanks, and the main propellant tanks. The most important result of the study is related to the confidence gained that mercury bombardment ion thruster systems can be built and operated in space on a routine basis with the same lifetime and performance as measured in ground testing.

Kerslake, W. R.↗
NASA NTRS1984

Ringed planets - Still mysterious. I

The ring systems of Jupiter, Saturn and Uranus have been studied particularly since the Voyager flights, in order to obtain more information on the rings' origin and structure. These ring systems all have satellites but the structure and number of satellites are different. Jupiter, with its two satellites, has a ring that is roughly 6000 km wide while Uranus has nine ringlets, most of which are no wider than tens of kilometers and which are separated by empty space. The three planetary ring systems also show distinctions in composition; for example, the rings of Saturn are thought to be icy while Jupiter's consist mostly of rocky material. The effect that countless particles, which make up each ring and interact with each other through collisions and gravitational attractions, have on the system's energy and angular momentum has been discussed. Spiral density waves and spiral bending waves, are explained by the resonance theory. Further study is needed in this area since the resonance theory does not account for all observed ring structures.

Cuzzi, J. N.↗
NASA NTRS1985

Ringed planets - Still mysterious. II

The morphology of the rings of Saturn and the mechanisms proposed to explain their fluctuations and origin are discussed and illustrated with photographs and diagrams in a general review. The kinks and braids of the F ring are attributed to the gravitational effects of the known shepherding satellites and/or a number of as yet unseen moonlets; the irregular gaps in the B and inner A rings, to particle interactions (diffusion-instability processes); and the flickering spokes of the central B ring, to the rotation of the Saturn magnetic field. It is pointed out that the composition of the single Jovian ring and of the Jovian satellites can be explained if both are remnants of the planet's primordial disk, but that the rock-ice compositions of the rings and inner satellites of Saturn require a more sophisticated model, perhaps involving meteoroid erosion. The rings of Uranus and Neptune are briefly considered.

Cuzzi, J. N.↗
NASA NTRS1986

Compendium of meteorology scientific issues of 1950 still outstanding

The Compendium of Meteorology was published in 1951 by the American Meteorological Society. A review was made of the Compendium of Meteorology to identify the studies and future needs which the authors expressed in their papers. The needs as seen by the authors are organized into sections and papers following the format of the Compendium of Meteorology. In some cases the needs they identified are as valid today as they were in 1951. In other cases one will easily be able to identify examples where significant progress has been made. It is left to the individual scientists and scientific program managers to assess whether significant progress has been made over the past thirty-five years on these outstanding scientific issues.

Vaughan, W. W.↗
NASA NTRS1987

Translation and execution of distributed Ada programs - Is it still Ada?

Some of the fundamental issues and tradeoffs for distributed execution systems for the Ada language are examined. Steps that need to be taken to deal with heterogeneity of addressing program objects, of processing resources, and of the individual processor environment are considered. The ways in which program elements can be assigned are examined in the context of four issues: implied remote object access, object visibility and recursive execution, task termination problems, and distributed types.

Volz, Richard A.↗
NASA NTRS1990

U.S. liquid propulsion technology stands still

NASA is currently conducting a comprehensive reevaluation of such fundamental launch vehicle-related issues as the appropriate balance between manned and unmanned launchers, reusable vs expendable vehicles and vehicle components, and the evolutionary vs innovative new-system development courses. Two trends have emerged, both emphasizing system expense: (1) low cost/manned flight vehicles for personnel transfer, small payloads, servicing, rescue, and Space Station logistics, and (2) low cost/unit mass vehicles for large and multiple payloads, propellants, bulk cargoes, and heavy upper stages. Attention is given to the contributions made by CFD to liquid-fueled engine component design.

Mccarty, John P.↗
NASA NTRS1992

Electronic Still Camera

A handheld, programmable, digital camera is disclosed that supports a variety of sensors and has program control over the system components to provide versatility. The camera uses a high performance design which produces near film quality images from an electronic system. The optical system of the camera incorporates a conventional camera body that was slightly modified, thus permitting the use of conventional camera accessories, such as telephoto lenses, wide-angle lenses, auto-focusing circuitry, auto-exposure circuitry, flash units, and the like. An image sensor, such as a charge coupled device ('CCD') collects the photons that pass through the camera aperture when the shutter is opened, and produces an analog electrical signal indicative of the image. The analog image signal is read out of the CCD and is processed by preamplifier circuitry, a correlated double sampler, and a sample and hold circuit before it is converted to a digital signal. The analog-to-digital converter has an accuracy of eight bits to insure accuracy during the conversion. Two types of data ports are included for two different data transfer needs. One data port comprises a general purpose industrial standard port and the other a high speed/high performance application specific port. The system uses removable hard disks as its permanent storage media. The hard disk receives the digital image signal from the memory buffer and correlates the image signal with other sensed parameters, such as longitudinal or other information. When the storage capacity of the hard disk has been filled, the disk can be replaced with a new disk.

Holland, S. Douglas↗
NASA NTRS1924

Motion of spheres in still fluids

The behavior of a liquid or gaseous medium, in which a solid body can move freely under the action of a force of constant magnitude and direction, is yet little known.

AERODYNAMICS↗