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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

(abstract) Application of Space Technology to NDE at JPL

JPL is responsible for the deep space exploration using spacecraft and telerobotic technologies. Since all its missions are one of a kind and hardware dependent, the NDE requirements are significantly more stringent than the ones for aerospace conventional needs. The multidisciplinary technologies that have been developed at JPL, particularly the ones that were developed for the exploration of Mars, can find applications to a wide variety of NDE applications. A review will be given of the recent JPL NDE activity and it will include several short videos.

nondestructive evaluation Mars spacecraft testing↗
NASA NTRS1997

(abstract) 9 (micro)m Cutoff 640x480 Quantum Well Infrared Photodetector (QWIP) Focal Plane Array Camera

Long wavelength infrared (LWIR) detectors, 8 (micro)m to 12 (micro)m, are of great interest for a variety of ground-based and space-borne applications. These applications have placed stringent requirements on the performance of the infrared detectors and arrays including high detectivity, low dark current, uniformity, radiation hardness, and low power dissipation. I will discuss the development and progress of GaAs based long-wavelength quantum well infrared photodetectors (QWIPs) to meet those stringent requirements and the demonstration of a 9 (micro)m cutoff 640x480 QUIP focal plane array camera. The noise equivalent temperature difference of the focal plane array is 25 mK at 300 K background and the operating temperature is 70 K.

long wavelength infrared detectors LWIR detector a↗
NASA NTRS1997

(abstract) Applications of Long-wavelength 256x256 GaAs/Al&subx;Ga&sub1-x;As Quantum Well Infrared Photodetector Hand-held Camera

A 9 (micro)m 256x256 hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE(gamma)) of 26 mK has been achieved. In this presentation, we discuss the development of this very sensitive long wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array, its performance in quantum efficience, NA(gamma), minimum resolvable temperature (MRTD), uniformity, operability, and its applications.

GaAs infrared photodetector quantum well QUIP nois↗
NASA NTRS1996

(abstract) The Role of the Deep Space Network for Cassini

Cassini radio science experiments have several categories of requirements for DSN tracking services. The three main areas for upgrade are in Ka-band, long-term frequence stability, and short-term frequency stability/phase noise level.

Cassini Deep Space Network telecommunications Grav↗
NASA NTRS1997

(abstract) The Galileo Spacecraft: A Telecommunications Legacy for Future Space Flight

The Galileo mission to Jupiter has implemented a wide range of telecommunication improvements in response to the loss of its high gain antenna. While necessity dictated the use of these new techniques for Galileo, now that they have been proven in flight, they are available for use on future deep space missions. This telecommunications legacy of Galileo will aid in our ability to conduct a meaningful exploration of the solar system, and beyond, at a reasonable cost.

Galileo telecommunications Deep Space Network↗
NASA NTRS1996

Direct Observation of Momentum Conservation at the Au/Si Interface Using BEEM (abstract)

The verification of parallel momentum conservation at a metal/semiconductor interface is a fundamental issue in interface transport. Ballistic-electron-microscopy (BEEM) is a recently developed method for probing interfaces with nanometer resolution. In this talk, BEEM spectroscopy on Au/Si(111) structures as a function of Au thickness and temperature will be described.

metal/semiconductor interface ballistic-electron-e↗
NASA NTRS1997

(abstract) Case Study of the Design of a Viterbi Decoder

This paper describes the design of an ASIC performing the Viterbi decoder function with a constraint length of 15 and at a speed of 4.4 Mb/s. The architecture of the chip is described, as well as the design challenges which were overcome. The author also describes the successful application of the design system.

Viterbi decoders ASIC chip architecture constraint↗
NASA NTRS1997

(abstract) Application of the GPS Worldwide Network in the Study of Global Ionospheric Storms

Ionospheric storm dynamics as a response to the geomagnetic storms is a very complicated global process involving many different mechanisms. Studying ionospheric storms will help us to understand the energy coupling process between the Sun and Earth and possibly also to effectively forecast space weather changes. Such a study requires a worldwide monitoring system. The worldwide GPS network, for the first time, makes near real-time global ionospheric TEC measurements a possibility.

GPS ionospheric storms communications geomagnetic ↗
NASA NTRS1996

Effects of Nucleus Ice Annealing History on Cometary Outgassing (abstract)

An important consideration for comet modeling is the dependence of the thermal conductivity on the comet structure. The microporosity of the comet ices changes with time as the phase of the ice and its annealing history progresses. Effects of these [modeled] changes on the overall gas production, as a function of time, are presented.

comet outgassing annealing ice dust thermal conduc↗
NASA NTRS1996

(abstract) Role of Long Equatorial Wave Reflection in the Low-Frequency Variability Observed During the TOPEX/POSEIDON Period: Data Analysis and Coupled Model Study

The analysis of TOPEX/POSEIDON sea level and ERS-1 zonal wind stress data gives evidence that first mode meridonal long Rossby waves fully reflected into Kelvin waves at the equatorial western Pacific boundary at different periods including the January-June 1994 period. The evolution of the conditions (zonal wind stress, sea surface temperature and sea level anomalies) in the central Pacific suggests that this reflection may have played a role in the reversal of cold to warm anomalies observed in the central Pacific in June-July 1994. To investigate the actual role of reflected Kelvin waves observed by TOPEX/POSEIDON, a simple ocean-atmosphere coupled model is designed. Starting from these initial conditions, several simulations are run for testing the role western bundary reflection evidenced in TOPEX/POSEIDON data. Coupled mechanisms are suggested to explain the low-frequency variability observed during this period.

Rossby waves Kelvin waves zonal wind stress TOPEX/↗
NASA NTRS1996

Gravitational Wave Search with the Clock Mission (abstract)

Doppler tracking of distant spacecraft is the only method currently available for search for gravitational waves in the low-frequency band. Experiments to date and those planned for the near future all involve.

clocks gravitational waves doppler frequency stand↗
NASA NTRS1996

(abstract) OMEGA: A Gravitational Wave MIDEX Mission

Among the low frequency (LF) gravitational wave sources that are of astronomical interest are white dwarf binaries, neutron star binaries, massive black hole binaries, and compact stars spiralling into massive black holes. A mission to detect these sources has been proposed to NASA as a possible member of its low-cost, near-term MIDEX mission series. This mission utilizes six tiny miniprobes in high Earth orbit to produce a sensitive Michelson interferometer with million kilometer arms, yielding a strain sensitivity below 10^{-21} at periods longer than a hundred seconds. At this sensitivity, known binary stars will be seen and plausible unknown massive black hole events will be searched for.

gravitational waves binaries black holes neutron s↗
NASA NTRS1996

(abstract)

The paper will review the application of NASA developed remote sensing technology towards the monitoring and mitigation of natural hazards. The overview will be followed by recent data on three specific natural hazard applications.

remote sensing natural hazards fire hazards infrar↗
NASA NTRS1996

(abstract) NDE and Advanced Actuators at JPL

JPL is responsible for deep space exploration using spacecraft and telerobotic technologies. Since all JPL's missions are one of a kind and hardware dependent, the requirements for nondestructive evaluation (NDE) of the materials and structures that are employed are significantly more stringent than the ones for conventional aerospace needs. The multidisciplinary technologies that are developed at JPL, particularily the ones for the exploration of Mars, are finding applications to a wide variety of NDE applications. Further, technology spin-offs are enabling the development of advanced actuators that are being used to drive various types of telerobotic devices. A review will be given of the recent JPL NDE and advanced actuators activity and it will include several short videos.

nondestructive evaluation actuators telerobotics t↗
NASA NTRS1996

(abstract) The Evolving Spaceborne Radar Data Support to Earth Science and Operations at the Alaska SAR Facility

The Alaska SAR Facility (ASF) has been receiving, processing, archiving, and distributing data for Earth scientists and operations since it began receiving data in 1991. Four radar satellites are now being handled. Recent developments have served to increase the level of services of ASF to the Earth science community considerably. These developments are discussed.

mapping radar interferometry Alaska topography ant↗
NASA NTRS1997

(abstract) Galileo Navigation: Launch to Jupiter Orbit

The Galileo spacecraft was launched on October 18, 1989. After a 3.7 billion kilometer journey lasting just over six years, the Galileo Orbiter and Probe arrived at Jupiter on December 7, 1995. The atmospheric Probe survived its atmospheric entry and successfully transmitted data to the Orbiter flying overhead. To date, the Orbiter has successfully completed the first three of the ten planned satellite encounters. Navigation for the Galileo Mission has proved to be a unique and challenging task. The challenges and results of navigating Galileo through the interplanetary transfer to Jupiter, delivery of the atmospheric entry Probe, Jupiter orbit insertion, and the orbital tour are presented in this paper.

Galileo Jupiter navigation orbits gravity assists ↗