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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 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

High T(sub c) leads for remote sensing applications

Several NASA programs designed to monitor the Earth's atmosphere from space utilize infrared detectors which operate at or below 4.2 K for optimum performance. At present, the detectors are maintained at cryogenic temperatures by a stored volume of liquid helium. These detectors must be electrically linked to amplification electronics data storage instruments maintained at 80 K. The electrical connections over the temperature gradient account for approximately 20% of the total heat load on the Dewar for some systems, accelerating the boil-off of liquid helium cryogen and reducing the operational lifetime of the space-borne instruments. The recent discovery of high temperature superconductors has provided an opportunity to develop electrically conductive, thermally insulating links to bridge this thermal gradient. This paper describes the modelling of the thermal transport properties of thick film, high T(sub c) electrical bridges across a 4.2-80 K temperature gradient and the impact of such devices on a spaceborne remote sensing system.

Selim, R.↗
NASA NTRS1980

The development of a stepped frequency microwave radiometer and its application to remote sensing of the Earth

The design, development, application, and capabilities of a variable frequency microwave radiometer are described. This radiometer demonstrated the versatility, accuracy, and stability required to provide contributions to the geophysical understanding of ocean and ice processes. A closed-loop feedback method was used, whereby noise pulses were added to the received electromagnetic radiation to achieve a null balance in a Dicke switched radiometer. Stability was achieved through the use of a constant temperature enclosure around the low loss microwave front end. The Dicke reference temperature was maintained to an absolute accuracy of 0.1 K using a closed-loop proportional temperature controller. A microprocessor based digital controller operates the radiometer and records the data on computer compatible tapes. This radiometer exhibits an absolute accuracy of better than 0.5 K when the sensitivity is 0.1 K. The sensitivity varies between 0.0125 K and 1.25 K depending upon the bandwidth and integration time selected by the digital controller. Remote sensing experiments were conducted from an aircraft platform and the first radiometeric mapping of an ocean polar front; exploratory experiments to measure the thickness of lake ice; first discrimination between first year and multiyear ice below 10 GHz; and the first known measurements of frequency sensitive characteristics of sea ice.

Harrington, R. F.↗
NASA NTRS1972

Considerations for the design of an onboard air traffic situation display

The basic concept of remoting information to the cockpit is used to design and develop a computerized airborne traffic situation display device that automatically selects and presents segments of a controller's scope to the aircraft pilot via a narrow band digital data link. These data are integrated with aircraft heading and navigation information to provide a display useful in congested air space. The display can include alphanumerical symbols, air route maps, and controller instructions.

Anderson, R. E.↗
NASA NTRS1983

Galilean satellite remote sensing by the Galileo Jupiter Orbiter

The derivation of a mission design strategy for the Galileo Jupiter Orbiter which best satisfies the requirements for remote sensing of the surfaces of the Galilean satellites during a 20-month orbital tour of the Jovian system is described. The celestial mechanics of a spacecraft orbiting about Jupiter and interacting with the Galilean satellites is discussed. A satellite tour strategy designed to optimize the accomplishment of remote sensing, field and particle science, and radio science objectives is developed. Finally, an assessment is made of how well these objectives can be met given the spacecraft, the capabilities of the scientific instruments, and the structure of the satellite tour.

Yeates, C. M.↗
NASA NTRS1974

First results from the crop identification technology assessment for remote sensing /CITARS/

The CITARS task design, including objectives, analysis methodology and experimental procedures, is described and first results from this effort are presented. The extensive ground truth data set acquired for the CITARS task is described and discussed in some detail. Results of the accuracy tests for the photo interpretative CITARS ground truth are given. Results of the assessment of the ERTS MSS data for cloud cover and electronic quality are presented. Some results of the geometric correction and registration of the time sequential CITARS ERTS data are given. Finally, the field boundary selection problem is addressed and the results of the use of new technology for boundary selection are presented.

Hall, F. G.↗
NASA NTRS1974

Atmospheric correction of remotely sensed spacecraft data

A model designed to predict the transfer of radiative energy in the earth atmosphere is described. The computational procedure accounts for absorption and scattering processes at visible and near infrared wavelengths. This paper reports on application of the atmospheric model to the interpretation of ERTS Multispectral Scanner (MSS) data. Spectrally-averaged values of the radiance emerging at the top of the atmosphere are computed for each MSS Band. It is concluded that ERTS MSS Band 4 data are to a high degree influenced by the water vapor content of the atmospere. Knowledge of the meteorological conditions at the time of an ERTS overpass appears to be necessary in order to achieve maximum classification accuracy. The impact of this conclusion upon the accuracy of identification of surface features will next be determined.

Jurica, G. M.↗
NASA NTRS1982

Radiometric considerations in remote sensing systems

All sensors systems designed to acquire quantitative data undergo radiometric calibration. The types and potential accuracies of calibration are discussed as well as the needs for calibration in the practical application of sensors. The recent and ongoing experience with the shuttle multispectral infrared radiometer is used as a reference.

Goetz, A. F. H.↗
NASA NTRS1985

A remotely controlled orbiting retriever

A preliminary design effort was recently carried out to investigate methods of removing a certain class of space objects from Shuttle type orbits. Specifically, expired satellites, upper stages, and other objects of potential danger to the Shuttle are the targets of the study. The Trash Remover and Satellite Hauler (TRASH-1) design effort was broken into several disciplines: mission analysis, systems engineering, dynamics and control, power, thermal, and propulsion. A basic requirements is that TRASH-1 go up in the Shuttle. It must be reusable and capable of disposing of more than one item per mission for cost effectiveness. These requirements imply TRASH-1 should use current technology, be modular in design, and be relatively maneuverable. In order to maximize utility, it should be able to both capture and deorbit objects. The design was a basic bus with attachable modules which can either capture or deorbit, depending on the module.

Kaplan, M. H.↗
NASA NTRS1989

Laser applications in meteorology and earth and atmospheric remote sensing; Proceedings of the Meeting, Los Angeles, CA, Jan. 16-18, 1989

Various papers on laser applications in meteorology and earth and atmospheric remote sensing are presented. The individual topics addressed include: solid state lasers for the mid-IR region, tunable chromium lasers, GaInAsSb/AlGaAsSb injection lasers for remote sensing applications, development and design of an airborne autonomous wavemeter for laser tuning, fabrication of lightweight Si/SiC lidar mirrors, low-cost double heterostructure and quantum-well laser array development, nonlinear optical processes for the mid-IR region, simulated space-based Doppler lidar performance in regions of backscatter inhomogeneities, design of CO2 recombination catalysts for closed-cycle CO2 lasers, density measurements with combined Raman-Rayleigh lidar, geodynamics applications of spaceborne laser ranging, use of aircraft laser ranging data for forest mensuration, remote active spectrometer, multiwavelngth and triple CO2 lidars for trace gas detection, analysis of laser diagnostics in plumes, laser atmospheric wind sounder, compact Doppler lidar system using commercial off-the-shelf components, and preliminary design for a laser atmospheric wind sounder.

Sokoloski, Martin M.↗
NASA NTRS1996

Interface Circuit For Connecting Instruments To Computers

Circuit card designed to act as interface between K-bus remote terminal. Enables digital communication between electronic instrumentation designed to communicate with other equipment via K-bus and control and telemetry-monitoring computer designed to communicate with other equipment via MIL-STD-1553B (or MIL-STD-1773) bus. Provides K-bus interface for as many as four instrumentation circuit cards.

Katz, Richard B.↗
NASA NTRS1986

HiMAT flight program: Test results and program assessment overview

The Highly Manueverable Aircraft Technology (HiMAT) program consisted of design, fabrication of two subscale remotely piloted research vehicles (RPRVs), and flight test. This technical memorandum describes the vehicles and test approach. An overview of the flight test results and comparisons with the design predictions are presented. These comparisons are made on a single-discipline basis, so that aerodynamics, structures, flight controls, and propulsion controls are examined one by one. The interactions between the disciplines are then examined, with the conclusions that the integration of the various technologies contributed to total vehicle performance gains. An assessment is made of the subscale RPRV approach from the standpoint of research data quality and quantity, unmanned effects as compared with manned vehicles, complexity, and cost. It is concluded that the RPRV technique, as adopted in this program, resulted in a more complex and costly vehicle than expected but is reasonable when compared with alternate ways of obtaining comparable results.

Deets, Dwain A.↗
NASA NTRS2004

Open-systems architecture of a standardized command interface chip-set for switching and control of a spacecraft power bus

The Jet Propulsion Laboratory (JPL) has developed a command interface chip-set that primarily consists of two mixed-signal ASICs'; the Command Interface ASIC (CIA) and Analog Interface ASIC (AIA). The Open-systems architecture employed during the design of this chip-set enables its use as both an intelligent gateway between the system's flight computer and the control, actuation, and activation of the spacecraft's loads, valves, and pyrotechnics respectfully as well as the regulator of the spacecraft power bus. Furthermore, the architecture is highly adaptable and employed fault-tolerant design methods enabling a host of other mission uses including reliable remote data collection. The objective of this design is to both provide a needed flight component that meets the stringent environmental requirements of current deep space missions and to add a new element to a growing library that can be used as a standard building block for future missions to the outer planets.

flight computers↗
NASA NTRS2018

The Hayabusa2 Sample Return Mission and Its Small Carry-On Impactor Experiment

On December 3, 2014 the Hayabusa2 Spacecraft was launched by JAXA to investigate and return samples from carbonaceous Asteroid (162173) Ryugu. The spacecraft's payload contains several remote sensing instruments that are designed to characterize the asteroid's surface and to help identify scientifically interesting locations from which samples can be obtained safely. The data collected by these instruments will also help place any obtained samples in context with respect to the global characteristics of Ryugu. In addition to the suite of remote sensing instruments and the sampling device, Hayabusa2 also includes a small carry-on impactor (SCI) payload experiment, which is designed to impact the surface of the asteroid and excavate fresh material for subsequent collection. The SCI consists of a 30 cm diameter 2 kg copper disk that is accelerated by an explosive charge into the surface of Ryugu at approximately 2 km/s. The resultant crater formed during this experiment is estimated to be approximately between 2 - 10 meters in diameter with an ejecta blanket extending to 10 - 100 meters on the asteroid. Hayabusa2 will not be able to observe the impact experiment directly due to considerations of spacecraft safety since there is some risk of collisions with debris from the explosion and ejecta from the crater. However, prior to moving safely away, the spacecraft will deploy a small imaging system called Deployable Camera 3 (DCAM3). DCAM3 will detach from Hayabusa2 just before the detonation of the SCI and will image the moment of impact, crater formation, and ejecta propagation. These data will be transmitted to Hayabusa2 and will help constrain the near-surface properties of Ryugu and also impact scaling laws for small bodies in low gravity environments. These data could also be useful for gaining insights into determining asteroid physical properties from higher velocity impact events (e.g., DART and HERA data of Didymos).

Abell, Paul A.↗
NASA NTRS2014

High Efficiency, 100 mJ per pulse, Nd:YAG Oscillator Optimized for Space-Based Earth and Planetary Remote Sensing

We report on a newly solid state laser transmitter, designed and packaged for Earth and planetary space-based remote sensing applications for high efficiency, low part count, high pulse energy scalability/stability, and long life. Finally, we have completed a long term operational test which surpassed 2 Billion pulses with no measured decay in pulse energy.

Remote Sensing↗
NASA NTRS1972

Design studies of lift fan engines suitable for use in civilian VTOL aircraft

Low pressure ratio fan engines are receiving increasing attention as a means to provide low speed lift for civilian VTOL transports. Two general types of fan lift engines that are being studied are integral fans and remote power fans. Preliminary engine design studies of both types of lift fan systems have been made. The paper summarizes a portion of the results of the engine design studies, including the crucial engine requirements, and some of the characteristics of the emerging engine designs of each type.

Roelke, R. J.↗
NASA NTRS1973

Control of turbofan lift engines for VTOL aircraft

The use of turbofan engines as lift units for VTOL aircraft poses new engine control problems. At low flight speeds, the lift units must provide the fast thrust response needed for aircraft attitude and height control. The results are presented of an analytical study of the dynamics and control of turbofan lift engines, and methods are proposed for meeting the response requirements imposed by the VTOL aircraft application. Two types of lift fan engines are discussed: the integral and remote. The integral engine is a conventional two-spool, high bypass ratio turbofan designed for low noise and short length. The remote engine employs a gas generator and a lift fan which are separated by a duct, and which need not be coaxial. For the integral engine, a control system design is presented which satisfies the VTOL response requirements. For the remote engine, two unconventional methods of control involving flow transfer between lift units are discussed. Both methods are shown to have thrust response near the required levels.

Sellers, J. F.↗