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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 1,441 records · Page 80
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Plasma contactor research - 1991

A report describing the operating principles of hollow-cathode-based plasma contactors emitting or collecting electrons from an ambient plasma is summarized. Preliminary experiments conducted to determine the noise generated by these plasma contactors in the emission-current return line and in the plasma near it are described. These noise data are measured as current fluctuations in the return line and to the Langmuir probe and then analyzed using a fast Fourier transform technique. The spectral compositions of the data are characterized using power spectral density plots which are examined to identify possible noise source(s) and production mechanism(s). The precautions taken in the construction and calibration of the instrumentation to assure adequate frequency response are described. Experimental results show that line-current noise levels are typically 2 percent of the electron current being emitted or collected. However, noise levels increase to as much as 20 percent of the electron current at a few electron-collection operating conditions. The frequencies associated with most of the noise were harmonics of the 60 Hz input to system power supplies. Plasma noise had characteristics similar in magnitude and frequency to those for the return-line noise, but they contained additional features at frequencies considered to be related to ion-acoustic instabilities. Also discussed is a new probe positioning system built to facilitate future plasma-contractor research.

Buchholtz, Brett↗
NASA NTRS2000

Microgravity Research Results and Experiences from the NASA Mir Space Station Program

The Microgravity Research Program Office (MRPO) participated aggressively in Phase I of the International Space Station Program using the Russian Mir Space Station. The Mir Station offered an otherwise unavailable opportunity to explore the advantages and challenges to long duration microgravity space research. Payloads with both NASA and commercial backing were included as well as cooperative research with the Canadian Space Agency (CSA). From this experience, much was learned about dealing with long duration on orbit science utilization and developing new working relationships with our Russian partner to promote efficient planning, operations, and integration to solve complexities associated with a multiple partner program. Microgravity participation in the NASA Mir Program began with the first joint NASA Mir flight to the Mir Space Station. The earliest participation setup acceleration measurement capabilities that were used throughout the Program. Research, conducted by all Microgravity science disciplines, continued on each subsequent increment for the entire three-year duration of the Program. The Phase I Program included the Microgravity participation of over 30 Fluids, Combustion, Materials, and Biotechnology Sciences and numerous commercially sponsored research payloads. In addition to the research gained from Microgravity investigations, long duration operation of facility hardware was tested. Microgravity facilities operated on Mir included the Space Acceleration Measurement System (SAMS), the Microgravity Glovebox (MGBX), the Biotechnology System (BTS) and the Canadian Space Agency sponsored Microgravity Isolation Mount (MIM). The Russian OPTIZONE Furnace was also incorporated into our material science research. All of these efforts yielded significant and useful scientific research data. This paper focuses on the microgravity research conducted onboard the Mir space station. It includes the Program preparation and planning necessary to support this type of cross increment research experience; the payloads which were flown; and summaries of significant microgravity science findings. Most importantly this paper highlights the various disciplines of microgravity research conducted during the International Space Station, Phase 1 Program onboard the Mir Station. A capsulation of significant research and the applicability of our findings are provided. In addition, a brief discussion of how future microgravity science gathering capabilities, hardware development and payload operations techniques have enhanced our ability to conduct long duration microgravity research.

Schagheck, R. A.↗
NASA NTRS2016

HIAD on ULA (HULA) Orbital Reentry Flight Experiment Concept

This paper describes a proposed orbital velocity reentry flight test of a Hypersonic Inflatable Aerodynamic Decelerator (HIAD). The flight test builds upon ground development activities that continue to advance the materials, design, and manufacturing techniques for the inflatable structure and flexible thermal protection system (F-TPS) that comprise the inflatable heat shield. While certain aspects of material and system performance can be assessed using a variety of ground testing capabilities, only orbital velocity energy on a trajectory through the gradient density of the atmosphere can impart the combined aerodynamic and aeroheating design environments in real time. To achieve this at limited cost, the HIAD would be delivered to a spin-stabilized entry trajectory as a secondary payload on the Centaur stage of a United Launch Alliance (ULA) Atlas V launch vehicle. Initial trajectory studies indicate that the combination of launch vehicle capability and achievable reentry vehicle ballistic numbers make this a strategic opportunity for technology development. This 4 to 6 meter diameter scale aeroshell flight, referred to as HIAD on ULA (HULA), would also contribute to ULA asset recovery development. ULA has proposed that a HIAD be utilized as part of the Sensible, Modular, Autonomous Return Technology (SMART) initiative to enable recovery of the Vulcan launch vehicle booster main engines [1], including a Mid-Air Recovery (MAR) to gently return these assets for reuse. Whereas HULA will attain valuable aerothermal and structural response data toward advancing HIAD technology, it may also provide a largest-to-date scaled flight test of the MAR operation, which in turn would allow the examination of a nearly pristine post-entry aeroshell. By utilizing infrared camera imaging, HULA will also attain aft-side thermal response data, enhancing understanding of the aft side aerothermal environment, an area of high uncertainty. The aeroshell inflation will utilize a heritage design compressed gas system to minimize development costs. The data will be captured to both an onboard recorder and a recorder that is jettisoned and recovered separately from the reentry vehicle to mitigate risk. This paper provides an overview, including the architecture and flight concept of operations, for the proposed HULA flight experiment.

Dinonno, J. M.↗
NASA NTRS1994

The SILEX experiment system operations

The European Space Agency is going to conduct an inter orbit link experiment which will connect a low Earth orbiting satellite and a Geostationary satellite via optical terminals. This experiment has been called SILEX (Semiconductor Inter satellite Link EXperiment). Two payloads will be built. One called PASTEL (PASsager de TELecommunication) will be embarked on the French Earth observation satellite SPOT4. The future European experimental data relay satellite ARTEMIS (Advanced Relay and TEchnology MISsion) will carry the OPALE terminal (Optical PAyload Experiment). The principal characteristic of the mission is a 50 Megabits flow of data transmitted via the optical satellite link. The relay satellite will route the data via its feeder link thus permitting a real time reception in the European region of images taken by the observation satellite. The PASTEL terminal has been designed to cover up to 9 communication sessions per day with an average of 5. The number of daily contact opportunities with the low earth orbiting satellite will be increased and the duration will be much longer than the traditional passes over a ground station. The terminals have an autonomy of 24 hours with respect to ground control. Each terminal will contain its own orbit model and that of its counter terminal for orbit prediction and for precise computation of pointing direction. Due to the very narrow field of view of the communication laser beam, the orbit propagation calculation needs to be done with a very high accuracy. The European Space Agency is responsible for the operation of both terminals. A PASTEL Mission Control System (PMCS) is being developed to control the PASTEL terminal on board SPOT4. The PMCS will interface with the SPOT4 Control Centre for the execution of the PASTEL operations. The PMCS will also interface with the ARTEMIS Mission Control System for the planning and the coordination of the operation. It is the first time that laser technology will be used to support inter-satellite links in Europe. Due to the complexity and experimental character of this new optical technology, the SILEX experiment control facilities will be designed to allow as much operational flexibility as possible.

Demelenne, B.↗
NASA NTRS1975

Manned orbital systems concepts study. Book 2: Requirements for extended-duration missions

In order to provide essential data needed in long-range program planning, the Manned Orbital Systems Concepts (MOSC) study attempted to define, evaluate, and compare concepts for manned orbital systems that provide extended experiment mission capabilities in space, flexibility of operation, and growth potential. Specific areas discussed include roles and requirements for man in future space missions, requirements for extended capability, mission/payload concepts, and preliminary design and operational requirements.

Source record↗
NASA NTRS1978

A study of 'onboard' data processing for typical astrophysics payloads

The data, signal flow, and ground processing requirements for a typical set of X-ray and gamma-ray experiments were examined. A set of algorithms for ground processing were derived and these were taken as requirements imposed on 'onboard' spacecraft computers. Five types of CPU microprocessors were evaluated and compared with one another to determine the degree to which the data processing could be performed onboard the spacecraft. These included the NASA Standard Spacecraft Computer (NSSC-1), the Z-80, a Z-80 augmented with an auxiliary fast multiply chip, and an advanced augmented Z-80 with virtually unlimited memory. These CPU were investigated when used in a centralized mode, an experiment dedicated mode, and a hybrid of the first two modes. It was found that the use of onboard processing can significantly reduce downlink data rates for typical payloads, and may lead to greater efficiency of operation. Quantitative data for gamma-ray and X-ray payloads will be presented, and the results of the analysis discussed.

Stout, C. M.↗
NASA NTRS1980

Global crop forecasting

The needs for and remote sensing means of global crop forecasting are discussed, and key results of the Large Area Crop Inventory Experiment (LACIE) are presented. Current crop production estimates provided by foreign countries are shown often to be inadequate, and the basic elements of crop production forecasts are reviewed. The LACIE project is introduced as a proof-of-concept experiment designed to assimilate remote sensing technology, monitor global wheat production, evaluate key technical problems, modify the technique accordingly and demonstrate the feasibility of a global agricultural monitoring system. The global meteorological data, sampling and aggregation techniques, Landsat data analysis procedures and yield forecast procedures used in the experiment are outlined. Accuracy assessment procedures employed to evaluate LACIE technology performance are presented, and improvements in system efficiency and capacity during the three years of operation are pointed out. Results of LACIE estimates of Soviet, U.S. and Canadian wheat production are presented which demonstrate the feasibility and accuracy of the remote-sensing approach for global food and fiber monitoring.

Macdonald, R. B.↗
NASA NTRS1983

Aerospace safety advisory panel

Data acquired on the actual flight experience with the various subsystems are assessed. These subsystems include: flight control and performance, structural integrity, orbiter landing gear, lithium batteries, EVA and prebreathing, and main engines. Improvements for routine operations are recommended. Policy issues for operations and flight safety for aircraft operations are discussed.

Source record↗
NASA NTRS1984

Nitrogen threshold experiment

In order to obtain data on Earth geologic processes associated with wind erosion, Mar's and Venus' atmospheres were simulated. Experiments were designed to observe the effects of pressure, gravity, and density on sand movement. An experiment designed to test the operator variance was a comparative test between nitrogen and carbon dioxide. Pressure and therefore density was increased until threshold was noted. Threshold was determined at precisely the same densities of the two gases. If viscosity were a contributing factor in grain saltation the effect would be noted at low pressures. The experiment showed no such variance between carbon dioxide and nitrogen runs for low pressure (density). The largest difference in viscosity between carbon dioxide and nitrogen occurs at low pressures (densities).

Treat, C. L.↗
NASA NTRS1984

Agribusiness and space: No limits to growth

Technological developments responding to world food needs are examined. It is noted that agribusiness technology has become more space-related in recent years. Although crops forecasting and improvements in yield (the green revolution) were developed prior to the space era, it would be unthinkable today to ignore the contributions of operational meteorological and communications satellites and experimental Earth observation satellites in agribusiness. Space-driven communications now permit national agribusiness database management networks, with a significant portion of the data being space-derived. In demonstration experiments, space communications were shown to improve those aspects of the food problem related to education and communications.

Montgomery, O. L.↗
NASA NTRS1985

The charge-energy-mass spectrometer for 0.3-300 keV/e ions on the AMPTE CCE

The charge-energy-mass (CHEM) spectrometer on the Charge Composition Explorer (CCE) has the function to measure the energy spectra, pitch-angle distributions, and ionization states of ions in the earth's magnetosphere and magnetosheath in the energy range from 0.3 to 300 keV/charge with a time resolution of less than 1 min. The obtained data will provide essential information on outstanding problems related to ion sources and dynamical processes of space plasmas and of suprathermal ions. A description of the CHEM experiment is given, taking into account the principle of operation, the sensor, the electronics, instrument characteristics, specifications, and requirements. Questions of postlaunch performance are also discussed.

Gloeckler, G.↗
NASA NTRS1986

Laminar flow integration: Flight tests status and plans

Under the Aircraft Energy Efficiency - Laminar Flow Control Program, there are currently three flight test programs under way to address critical issues concerning laminar flow technology application to commercial transports. The Leading-Edge Flight Test (LEFT) with a JetStar aircraft is a cooperative effort with the Ames/Dryden Flight Research Facility to provide operational experience with candidate leading-edge systems representative of those that might be used on a future transport. In the Variable Sweep Transition Flight Experiment (VSTFE), also a cooperative effort between Langley and Ames/Dryden, basic transition data on an F-14 wing with variable sweep will be obtained to provide a data base for laminar flow wing design. Finally, under contract to the Boeing Company, the acoustic environment on the wing of a 757 aircraft will be measured and the influence of engine noise on laminar flow determined with a natural laminar flow glove on the wing. The status and plans for these programs are reported.

Wagner, R. D.↗
NASA NTRS1990

Failure of the ERBE scanner instrument aboard NOAA 10 spacecraft and results of failure analysis

The Earth Radiation Budget Experiment (ERBE) scanner instrument on the NOAA 10 spacecraft malfunctioned on May 22, 1989, after more than 4 years of in-flight operation. After the failure, all instrument operational mode commands were tested and the resulting data analyzed. Details of the tests and analysis of output data are discussed therein. The radiometric and housekeeping data appear to be valid. However, the instrument will not correctly execute operational scan mode commands or the preprogrammed calibration sequences. The data indicate the problem is the result of a failure in the internal address decoding circuity in one of the ROM (read only memory) chips of the instrument computer.

Miller, J. B.↗
NASA NTRS1991

Comparison of GLONASS and GPS time transfers between two west European time laboratories and VNIIFTRI

The University of Leeds built a GPS/GLONASS receiver about five years ago and since then has provided continuous information about GLONASS time and its comparison with GPS time. For the last two years VNllFTRl and some other Soviet time laboratories have used Soviet-built GLONASS navigation receivers for time comparisons. Since June 1991, VNIIFTRI has been operating a GPS time receiver on loan from the BIPM. This offered, for the first time, an opportunity for direct comparison of time transfers using GPS and GLONASS. This experiment shows that even with relatively imprecise data recording and processing, in terms of time metrology, GLONASS can provide continental time transfer at a level of several tens of nanoseconds.

P. Daly↗
NASA NTRS1992

Onboard configuration and operation of the TDRSS onboard navigation system (TONS)

This paper presents an overview of onboard navigation via TDRSS for both the EP/EUVE (Explorer Platform/Extreme Ultraviolet Explorer) experiment and for future users of TONS. System goals and objectives are discussed, and the operations concept for the three stages of TONS development is presented. A description is given of the first stage of the TONS development, the experiment implementation on EP, including the hardware characteristics, signal acquisition process, onboard data acquisition, and ground data processing in the flight emulation environment of the TONS Ground Support System (TGSS). Evaluation of the experiment implementation is presented and improvements described in terms of the second development stage, a full TONS I system, which uses Doppler data derived from scheduled forward-link S-band services to provide onboard orbit and frequency determination. A method for onboard time maintenance commensurate with TONS I is also presented. TONS II, the third stage, will use Doppler and pseudorange data derived from a continuous, nonscheduled forward-link S-band beacon service to provide onboard orbit, time, and frequency determination.

Gramling, Cheryl J.↗
NASA NTRS1993

Polarimetric Multispectral Imaging Technology

The Jet Propulsion Laboratory is developing a remote sensing technology on which a new generation of compact, lightweight, high-resolution, low-power, reliable, versatile, programmable scientific polarimetric multispectral imaging instruments can be built to meet the challenge of future planetary exploration missions. The instrument is based on the fast programmable acousto-optic tunable filter (AOTF) of tellurium dioxide (TeO2) that operates in the wavelength range of 0.4-5 microns. Basically, the AOTF multispectral imaging instrument measures incoming light intensity as a function of spatial coordinates, wavelength, and polarization. Its operation can be in either sequential, random access, or multiwavelength mode as required. This provides observation flexibility, allowing real-time alternation among desired observations, collecting needed data only, minimizing data transmission, and permitting implementation of new experiments. These will result in optimization of the mission performance with minimal resources. Recently we completed a polarimetric multispectral imaging prototype instrument and performed outdoor field experiments for evaluating application potentials of the technology. We also investigated potential improvements on AOTF performance to strengthen technology readiness for applications. This paper will give a status report on the technology and a prospect toward future planetary exploration.

Cheng, L.-J.↗
NASA NTRS1994

Limb-darkening models from along-track operation of the ERBE scanning radiometer

During January and August 1985, the scanning radiometers of the Earth Radiation Budget Experiment(ERBE) aboard the Earth Radiation Budget Satellite (ERBS) and the NOAA-9 satellite were operated in along-track scanning modes. Along-track scanning permits the study of many measurement problems. It provides the data for developing a limb-darkening model for a single site over a short period of time and also permits the indentification of the scene from data taken at smaller nadir angles. The earth-emitted radiation measured by the scanners has been analyzed to produce limb-darkening models for a variety of scene types. Limb-darkening models relate the radiance in any given direction to the radiant flux. The scene types were computed using measurements within 10 deg of zenith. The models have values near zenith of 1.02-1.09. The typical zenith values of the model are 1.06 for both day and night for ERBS, and for NOAA-9, 1.06 for day and 1.05 for night. Mean models are formed for the ERBS and NOAA-9 results and are found to differ less than 1%, the ERBS results being the higher. The models vary about 1% with latitude near zenith and agree with earlier models that were used to analyze ERBE data typically to 2%.

Smith, G. Louis↗
NASA NTRS2000

Characterization of Advanced Avalanche Photodiodes for Water Vapor Lidar Receivers

Development of advanced differential absorption lidar (DIAL) receivers is very important to increase the accuracy of atmospheric water vapor measurements. A major component of such receivers is the optical detector. In the near-infrared wavelength range avalanche photodiodes (APD's) are the best choice for higher signal-to-noise ratio, where there are many water vapor absorption lines. In this study, characterization experiments were performed to evaluate a group of silicon-based APD's. The APD's have different structures representative of different manufacturers. The experiments include setups to calibrate these devices, as well as characterization of the effects of voltage bias and temperature on the responsivity, surface scans, noise measurements, and frequency response measurements. For each experiment, the setup, procedure, data analysis, and results are given and discussed. This research was done to choose a suitable APD detector for the development of an advanced atmospheric water vapor differential absorption lidar detection system operating either at 720, 820, or 940 nm. The results point out the benefits of using the super low ionization ratio (SLIK) structure APD for its lower noise-equivalent power, which was found to be on the order of 2 to 4 fW/Hz(sup (1/2)), with an appropriate optical system and electronics. The water vapor detection systems signal-to-noise ratio will increase by a factor of 10.

Refaat, Tamer F.↗