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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 1,027 records · Page 57
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

EOS Terra Validation Program

The EOS Terra mission will be launched in July 1999. This mission has great relevance to the atmospheric radiation community and global change issues. Terra instruments include ASTER, CERES, MISR, MODIS and MOPITT. In addition to the fundamental radiance data sets, numerous global science data products will be generated, including various Earth radiation budget, cloud and aerosol parameters, as well as land surface, terrestrial ecology, ocean color, and atmospheric chemistry parameters. Significant investments have been made in on-board calibration to ensure the quality of the radiance observations. A key component of the Terra mission is the validation of the science data products. This is essential for a mission focused on global change issues and the underlying processes. The Terra algorithms have been subject to extensive pre-launch testing with field data whenever possible. Intensive efforts will be made to validate the Terra data products after launch. These include validation of instrument calibration (vicarious calibration) experiments, instrument and cross-platform comparisons, routine collection of high quality correlative data from ground-based networks, such as AERONET, and intensive sites, such as the SGP ARM site, as well as a variety field experiments, cruises, etc. Airborne simulator instruments have been developed for the field experiment and underflight activities including the MODIS Airborne Simulator (MAS), AirMISR, MASTER (MODIS-ASTER), and MOPITT-A. All are integrated on the NASA ER-2, though low altitude platforms are more typically used for MASTER. MATR is an additional sensor used for MOPITT algorithm development and validation. The intensive validation activities planned for the first year of the Terra mission will be described with emphasis on derived geophysical parameters of most relevance to the atmospheric radiation community. Detailed information about the EOS Terra validation Program can be found on the EOS Validation program homepage i/e.: http://ospso.gsfc.nasa.gov/validation/valpage.html).

Starr, David↗
NASA NTRS2000

Ground Based Operational Testing Of Holographic Scanning Lidars : The HOLO Experiments

Two aerosol backscatter lidar measurement campaigns were conducted using two holographic scanning lidars and one zenith staring lidar for the purposes of reliability testing under field conditions three new lidar systems and to develop new scanning measurement techniques and applications. The first campaign took place near the campus of Utah State University in Logan Utah in March of 1999 and is called HOLO-1. HOLO-2 was conducted in June of 1999 on the campus of Saint Anselm College, near the city of Manchester, New Hampshire. Each campaign covered a period of approximately one week of nearly continuous observation of cloud and aerosol backscatter in the visible and near infrared by lidar, and wide field visible sky images by video camera in the daytime. The scanning capability coupled with a high rep-rate, high average power laser enables both high spatial and high temporal resolution observations that Particularly intriguing is the possibility of deriving atmospheric wind profiles from temporal analysis of aerosol backscatter spatial structure obtained by conical scan without the use of Doppler techniques.

Schwemmer, Geary K.↗
NASA NTRS2000

EOS Terra Validation Program

The EOS Terra mission will be launched in July 1999. This mission has great relevance to the atmospheric radiation community and global change issues. Terra instruments include Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Clouds and Earth's Radiant Energy System (CERES), Multi-Angle Imaging Spectroradiometer (MISR), Moderate Resolution Imaging Spectroradiometer (MODIS) and Measurements of Pollution in the Troposphere (MOPITT). In addition to the fundamental radiance data sets, numerous global science data products will be generated, including various Earth radiation budget, cloud and aerosol parameters, as well as land surface, terrestrial ecology, ocean color, and atmospheric chemistry parameters. Significant investments have been made in on-board calibration to ensure the quality of the radiance observations. A key component of the Terra mission is the validation of the science data products. This is essential for a mission focused on global change issues and the underlying processes. The Terra algorithms have been subject to extensive pre-launch testing with field data whenever possible. Intensive efforts will be made to validate the Terra data products after launch. These include validation of instrument calibration (vicarious calibration) experiments, instrument and cross-platform comparisons, routine collection of high quality correlative data from ground-based networks, such as AERONET, and intensive sites, such as the SGP ARM site, as well as a variety field experiments, cruises, etc. Airborne simulator instruments have been developed for the field experiment and underflight activities including the MODIS Airborne Simulator (MAS) AirMISR, MASTER (MODIS-ASTER), and MOPITT-A. All are integrated on the NASA ER-2 though low altitude platforms are more typically used for MASTER. MATR is an additional sensor used for MOPITT algorithm development and validation. The intensive validation activities planned for the first year of the Terra mission will be described with emphasis on derived geophysical parameters of most relevance to the atmospheric radiation community.

Starr, David↗
NASA NTRS2000

A Windshear Hazard Index

An aircraft exposed to hazardous low-level windshear may suffer a critical loss of airspeed and altitude, thus endangering its ability to remain airborne. In order to characterize this hazard, a nondimensional index was developed based oil aerodynamic principals and understanding of windshear phenomena, 'This paper reviews the development and application of the Bowles F-tactor. which is now used by onboard sensors for the detection of hazardous windshear. It was developed and tested during NASA/I:AA's airborne windshear program and is now required for FAA certification of onboard radar windshear detection systems. Reviewed in this paper are: 1) definition of windshear and description of atmospheric phenomena that may cause hazardous windshear. 2) derivation and discussion of the F-factor. 3) development of the F-factor hazard threshold, 4) its testing during field deployments, and 5) its use in accident reconstructions,

Proctor, Fred H.↗
NASA NTRS2001

A Nanometer Aerosol Size Analyzer (nASA) for Rapid Measurement of High-Concentration Size Distributions

We have developed a fast-response Nanometer Aerosol Size Analyzer (nASA) that is capable of scanning 30 size channels between 3 and 100 nm in a total time of 3 seconds. The analyzer includes a bipolar charger (P0210), an extended-length Nanometer Differential Mobility Analyzer (Nano-DMA), and an electrometer (TSI 3068). This combination of components provides particle size spectra at a scan rate of 0.1 second per channel free of uncertainties caused by response-time-induced smearing. The nASA thus offers a fast response for aerosol size distribution measurements in high-concentration conditions and also eliminates the need for applying a de-smearing algorithm to resulting data. In addition, because of its thermodynamically stable means of particle detection, the nASA is useful for applications requiring measurements over a broad range of sample pressures and temperatures. Indeed, experimental transfer functions determined for the extended-length Nano-DMA using the Tandem Differential Mobility Analyzer (TDMA) technique indicate the nASA provides good size resolution at pressures as low as 200 Torr. Also, as was demonstrated in tests to characterize the soot emissions from the J85-GE engine of a T38 aircraft, the broad dynamic concentration range of the nASA makes it particularly suitable for studies of combustion or particle formation processes. Further details of the nASA performance as well as results from calibrations, laboratory tests and field applications are presented.

Han, Hee-Siew↗
NASA NTRS1998

Comparison of the X-Ray and Radio Light Curves of Quasar PKS 1510--089

We present results for the X-ray-bright superluminal AGN PKS 1510-089 (z=0.36) monitored weekly with the Rossi X-Ray Timing Explorer for the past four years in order to study the origin of X-ray emission from this extremely variable blazer. These RXTE data are compared with weekly cm-band flux and polarization observations from the Michigan Diameter telescope, to identify correlated activity and associated frequency-dependent time delays for constraining X-ray emission models; and bimonthly 7mm VLBA total and linearly polarized intensity imaging to identify temporal associations between X-ray events and the ejection of superluminal components and disturbances in the magnetic field, to test if the X-ray energy release is related to changes in the inner jet flow. Both the X-ray (2-20 keV) and radio flux are highly variable on timescales of weeks. The VLBA mas structure is dominated by a bright core with a weak jet; both the ejection of very fast superluminal knots and changes in the fractional polarization and EVPA of the core on timescales of one to four months are identified. Two outbursts in 1997 are well-resolved in both the centimeter and X-ray bands. Both the strong temporal association and the similar outburst shape support a causal relation, and a discrete cross-correlation analysis identifies that the X-ray lags the radio by 16 days during the bursts. Starting in 1998 the behavior changes: the correlation is weaker with the X-ray possibly leading the radio by six days. During the full time window there is a correlation between bands as expected if the radio photons are upscattered to X-ray energies. The time correlations and difference between the flat X-ray spectral index (0.0 <= alpha <= 0.5 where F(sub v) is proportional to v(exp -alpha)), and the mm-wave synchrotron spectrum (alpha = 0.8) are discussed within the framework of viable SSC models.

Aller, M. F.↗
NASA NTRS2003

Legacy and Emergence of Spaceport Technology Development at the Kennedy Space Center

Kennedy Space Center (KSC) has a long and successful legacy in the checkout and launch of missiles and space vehicles. These operations have become significantly more complex, and their evolution has driven the need for many technology developments. Unanticipated events have also underscored the need for a local, highly responsive technology development and testing capability. This evolution is briefly described, as well as the increasing level of technology capability at KSC. The importance of these technologies in achieving past national space goals suggests that the accomplishment of low-cost and reliable access to space will depend critically upon KSC's future success in developing spaceport technologies. This paper concludes with a description KSC's current organizational approach and major thrust areas in technology development. The first phase of our historical review focuses on the development and testing of field- deployable short- and intermediate-range ballistic missiles (1953 to 1958). These vehicles are later pressed into service as space launchers. The second phase involves the development of large space lift vehicles culminating in the Saturn V launches (1959 to 1975). The third phase addresses the development and operations of the partially reusable launch vehicle, Space Shuttle (1976 to 2000). In the current era, KSC is teaming with the U.S. Air Force (AF), industry, academia, and other partners to identify and develop Spaceport and Range Technologies necessary to achieve national space goals of lower-cost and higher-reliability space flight.

Starr, Stanley↗
NASA NTRS2003

Development and Testing of Laser-induced Breakdown Spectroscopy for the Mars Rover Program: Elemental Analyses at Stand-Off Distances

One of the most fundamental pieces of information about any planetary body is the elemental composition of its surface materials. The Viking Martian landers employed XRF (x-ray fluorescence) and the MER rovers are carrying APXS (alpha-proton x-ray spectrometer) instruments upgraded from that used on the Pathfinder rover to supply elemental composition information for soils and rocks to which direct contact is possible. These in- situ analyses require that the lander or rover be in contact with the sample. In addition to in-situ instrumentation, the present generation of rovers carry instruments that operate at stand-off distances. The Mini-TES is an example of a stand-off instrument on the MER rovers. Other examples for future missions include infrared point spectrometers and microscopic-imagers that can operate at a distance. The main advantage of such types of analyses is obvious: the sensing element does not need to be in contact or even adjacent to the target sample. This opens up new sensing capabilities. For example, targets that cannot be reached by a rover due to impassable terrain or targets positioned on a cliff face can now be accessed using stand-off analysis. In addition, the duty cycle of stand-off analysis can be much greater than that provided by in-situ measurements because the stand-off analysis probe can be aimed rapidly at different features of interest eliminating the need for the rover to actually move to the target. Over the past five years we have been developing a stand-off method of elemental analysis based on atomic emission spectroscopy called laser-induced breakdown spectroscopy (LIBS). A laser-produced spark vaporizes and excites the target material, the elements of which emit at characteristic wavelengths. Using this method, material can be analyzed from within a radius of several tens of meters from the instrument platform. A relatively large area can therefore be sampled from a simple lander without requiring a rover or sampling arms. The placement of such an instrument on a rover would allow the sampling of locations distant from the landing site. Here we give a description of the LIBS method and its advantages. We discuss recent work on determining its characteristics for Mars exploration, including accuracy, detection limits, and suitability for determining the presence of water ice and hydrated minerals. We also give a description of prototype instruments we have tested in field settings.

D A Cremers↗
NASA NTRS2004

The Formation Mechanism of Helium-Rich Subdwarf B Stars

This program used the Far Ultraviolet Spectroscopic Explorer (FUSE) to measure the surface abundances of three helium-rich hot subdwarfs in the Galactic field, to test our hypothesis that such stars form via a late helium flash while descending the white dwarf cooling curve. If these stars form via a late He flash, the stellar envelope should be mixed with the interior, enhancing the surface carbon abundance enormously while depleting the surface hydrogen. The first observation of PG1544+488 was incomplete because detector 2 was turned off, but the repeat observations were fully successful. The observations of LB1766 had no problems and were fully successful. The observations of PG1127+019 became infeasible when FUSE lost some of its pointing control, so it was replaced with JL87, which was also observed successfully.

Luers, Jeannine N.↗
NASA NTRS2004

Improving the Transition of Earth Satellite Observations from Research to Operations

There are significant gaps between the observations, models, and decision support tools that make use of new data. These challenges include: 1) Decreasing the time to incorporate new satellite data into operational forecast assimilation systems, 2) Blending in-situ and satellite observing systems to produce the most accurate and comprehensive data products and assessments, 3) Accelerating the transition from research to applications through national test beds, field campaigns, and pilot demonstrations, and 4) Developing the partnerships and organizational structures to effectively transition new technology into operations. At the Short-term Prediction Research and Transition (SPORT) Center in Huntsville, Alabama, a NASA-NOAA-University collaboration has been developed to accelerate the infusion of NASA Earth science observations, data assimilation and modeling research into NWS forecast operations and decision-making. The SPoRT Center research focus is to improve forecasts through new observation capability and the regional prediction objectives of the US Weather Research Program dealing with 0-1 day forecast issues such as convective initiation and 24-hr quantitative precipitation forecasting. The near real-time availability of high-resolution experimental products of the atmosphere, land, and ocean from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Advanced Infrared Spectroradiometer (AIRS), and lightning mapping systems provide an opportunity for science and algorithm risk reduction, and for application assessment prior to planned observations from the next generation of operational low Earth orbiting and geostationary Earth orbiting satellites. This paper describes the process for the transition of experimental products into forecast operations, current products undergoing assessment by forecasters, and plans for the future. The SPoRT Web page is at (http://www.ghcc.msfc.nasa.gov/sport).

Goodman, Steven J.↗
NASA NTRS2000

Strain Measurement System Developed for Biaxially Loaded Cruciform Specimens

A new extensometer system developed at the NASA Glenn Research Center at Lewis Field measures test area strains along two orthogonal axes in flat cruciform specimens. This system incorporates standard axial contact extensometers to provide a cost-effective high-precision instrument. The device was validated for use by extensive testing of a stainless steel specimen, with specimen temperatures ranging from room temperature to 1100 F. In-plane loading conditions included several static biaxial load ratios, plus cyclic loadings of various waveform shapes, frequencies, magnitudes, and durations. The extensometer system measurements were compared with strain gauge data at room temperature and with calculated strain values for elevated-temperature measurements. All testing was performed in house in Glenn's Benchmark Test Facility in-plane biaxial load frame.

Krause, David L.↗
NASA NTRS2006

Software Architecture of Sensor Data Distribution In Planetary Exploration

Data from mobile and stationary sensors will be vital in planetary surface exploration. The distribution and collection of sensor data in an ad-hoc wireless network presents a challenge. Irregular terrain, mobile nodes, new associations with access points and repeaters with stronger signals as the network reconfigures to adapt to new conditions, signal fade and hardware failures can cause: a) Data errors; b) Out of sequence packets; c) Duplicate packets; and d) Drop out periods (when node is not connected). To mitigate the effects of these impairments, a robust and reliable software architecture must be implemented. This architecture must also be tolerant of communications outages. This paper describes such a robust and reliable software infrastructure that meets the challenges of a distributed ad hoc network in a difficult environment and presents the results of actual field experiments testing the principles and actual code developed.

Lee, Charles↗
NASA NTRS2002

Test of a new field-theoretical crossover equation-of-state

A new field-theoretical crossover equation-of-state model provides a bridge between the asymptotic behavior close to a liquid-gas critical point and the expected mean field behavior farther away.

equation-of-state critical phenomena liquid-gas cr↗
NASA NTRS2005

Science operations interfaces for Mars surface exploration

The Science Activity Planner (SAP) is the science planning tool used for the Mars Exploration Rover (MER) mission. This paper begins with an overview of the software developed for MER and how it was used for science downlink analysis and activity planning.

distributed operations↗
NASA NTRS2007

Direct Field and Reverberant Chamber Acoustic Test Comparisons

Reverberant and direct acoustic test comparisons were analyzed in this viewgraph presentation. The acoustic test data set includes: 1) CloudSat antenna subjected to PF reverberant chamber acoustic test; 2) CloudSat subjected to a PF direct speaker acoustic test; and 3) DAWN flight spacecraft subjected to PF direct speaker and a workmanship reverberant chamber acoustic test.

acoustics↗
NASA NTRS2007

The First Year in Review: NASA's Ares I Crew Launch Vehicle and Ares V Cargo Launch Vehicle

The U.S. Vision for Space Exploration guides NASA's challenging missions of scientific discovery.' Developing safe, reliable, and affordable space transportation systems for the human and robotic exploration of space is a key component of fulfilling the strategic goals outlined in the Vision, as well as in the U.S. Space Policy. In October 2005, the Exploration Systems Mission Directorate and its Constellation Program chartered the Exploration Launch Projects Office, located at the Marshall Space Flight Center, to design, develop, test, and field a new generation of launch vehicles that would fulfill customer and stakeholder requirements for trips to the Moon, Mars, and beyond. The Ares I crew launch vehicle is slated to loft the Orion crew exploration vehicle to orbit by 2014, while the heavy-lift Ares V cargo launch vehicle will deliver the lunar lander to orbit by 2020 (Fig. 1). These systems are being designed to empower America's return to the Moon to prepare for the first astronaut on Mars. The new launch vehicle designs now under study reflect almost 50 years of hard-won experience gained from the Saturn's missions to the Moon in the late 1960s and early 1970s, and from the venerable Space Shuttle, which is due to be retired by 2010.

Dumbacher, Daniel L.↗
NASA NTRS2010

Integration of the Electrodynamic Dust Shield on a Lunar Habitat Demonstration Unit

NASA is developing a Habitat Demonstration Unit (HDU) to investigate the feasibility of lunar surface technologies and lunar ground operations. The HDU will define and validate lunar scenario architecture through field analog testing. It will contain a four-port vertical habitat module with docking demonstration capabilities. The Electrodynamic Oust Shield (EDS) is being incorporated into the HDU to demonstrate dust removal from a viewport and from a door prior to docking procedures. In this paper, we will describe our efforts to scale up the EDS to protect a viewport 20 cm in diameter. We will also describe the development of several 20 cm x 25 cm EDS patches to demonstrate dust removal from one of the HDU doors.

Calle, C. I.↗
NASA NTRS2010

A Balloon Sounding Technique for Measuring SO2 Plumes

This paper reports on the development of a new technique for inexpensive measurements of SO2 profiles using a modified dual-ozonesonde instrument payload. The presence of SO2 interferes with the standard electrochemical cell (ECC) ozonesonde measurement, resulting in -1 molecule of O3 reported for each molecule of SO2 present (provided [O3] > [SO2]). In laboratory tests, an SO2 filter made with Cr03 placed on the inlet side of the sonde removes nearly 100% of the SO2 present for concentrations up to 60 ppbv and remained effective after exposure to 2.8 X 10(exp 16) molecules of SO2 [equivalent to a column approximately 150 DU (1 DU = 2.69 X 10(exp 20) molecules m(exp -2))]. Flying two ECC instruments on the same payload with one filtered and the other unfiltered yields SO2 profiles, inferred by subtraction. Laboratory tests and field experience suggest an SO2 detection limit of approximately 3 pbb with profiles valid from the surface to the ozonopause [i.e., approximately (8-10 km)]. Two example profiles demonstrate the success of this technique for both volcanic and industrial plumes.

Morris, Gary A.↗