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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Single-chip microcomputer application in high-altitude balloon orientation system

This paper describes the application of a single-chip microcomputer in a high-altitude balloon instrumentation system. The system, consisting of a magnetometer, a stepping motor, a microcomputer and a gray code shaft encoder, is used to provide an orientation reference to point a scientific instrument at an object in space. The single-chip microcomputer, Intel's 8748, consisting of a CPU, program memory, data memory and I/O ports, is used to control the orientation of the system.

Lim, T. S.↗
NASA NTRS1969

An analysis of a navigation scheme for MLRV

Manned lunar roving vehicle /MLRV/ navigation scheme based on dead reckoning concept, discussing instruments effectiveness for vehicle velocity and orientation measurements

Hung, J. C.↗
NASA NTRS1976

Attitude transfer assembly design for MAGSAT

A description is given of a design for an instrument system that will monitor the orientation of a boom-mounted vector magnetometer relative to the main spacecraft body. The attitude of the magnetometer is measured with respect to X and Z axes lateral to the boom length and also a twist axis around the boom center line. These measurements are made in a noncontact optical approach employing a three-axis autocollimator system mounted on the main body of the spacecraft with only passive elements (reflectors) located at the end of the 20-foot boom.

Collyer, P. W.↗
NASA NTRS1980

Aircraft icing instrumentation: Unfilled needs

A list of icing instrumentation requirements are presented. Because of the Army's helicopter orientation, many of the suggestions are specific to rotary wing aircraft; however, some of the instrumentation are also suitable for general aviation aircraft.

Kitchens, P. F.↗
NASA NTRS1982

The Orthogonal In-Situ Machining of Single and Polycrystalline Aluminum and Copper, Volume 1

Metal cutting is a unique deformation process characterized by large strains, exceptionally high strain rates and few constraints to the deformation. These factors, along with the difficulty of directly measuring the shear angle, make chip formation difficult to model and understand. One technique for skirting the difficulty of post mortem chip measurement is to perform a cutting experiment dynamically in a scanning electron microscope. The performance of the in-situ experiment with full instrumentation allows for component force measurement, orientation measurement (on a round single crystal disk) and a timing device, all superimposed below the deformation on the TV monitor and recorded for future viewing. This allows the sher angle to be directly measured for the screen along with the other needed information.

Cohen, P. H.↗
NASA NTRS1988

A cosmic and solar X-ray and gamma-ray instrument for a scout launch

An overview is presented for a set of simple and robust X-ray and gamma ray instruments which have both cosmic and solar objectives. The primary solar scientific objective is the study of the beaming of energetic electrons and ions in solar flares. The instrument will measure spectra and polarization of flare emissions up to 10 MeV. At X-ray energies both the directly emitted flux and the reflected albedo flux will be measured with a complement of six X-ray sensors. Each of these detectors will have a different high Z filter selected to optimize both the energy resolution and high rate capabilities in the energy band 10 to 300 keV. At energies greater than 100 keV seven 7.6 x 7.6 cm NaI and a set of 30 concentric plastic scattering detectors will record the spectra and polarization of electron bremsstrahlung and nuclear gamma rays. All of the components of the instrument are in existence and have passed flight tests for earlier space missions. The instrument will use a spinning solar oriented Scout spacecraft. The NaI detectors will act as a self-modulating gamma ray detector for cosmic sources in a broad angular band which lies at 90 degrees to the Sun-Earth vector and hence will scan the entire sky in 6 months.

Forrest, D. J.↗
NASA NTRS1994

On the problem of measuring interannual wind speed variations using SSMI data

The first Special Sensor Microwave Imager (SSMI) was launched on the Defense Meteorological Satellite Program (DMSP) F8 spacecraft in July 1987, and wind speed was no longer retrieved after December 1991. A second SSMI was launched on DMSP F10 in December 1990. Interpretation of the 1987-1993 (or longer) SSMI wind speed time series is dependent upon the space and time characteristics of the differences between F8 and F10 SSMI measurements. The 10 deg-zonal averaged monthly mean F8-F10 wind speed difference was negative (positive) for wind speeds less (greater) than 7.9 m/s, reaching -0.43 (0.32) m/s at 5(10) m/s. Between 60 deg S and 60 deg N the 10 deg-zonal averaged monthly mean F8-F10 wind speed bias was greater than +/- 0.5 m/s on several occasions. From 60 deg S - 60 deg N the 1991 average value of the monthly mean root-mean-square difference between daily F8 and F10 wind speeds in 10 deg-longitudinal bands was 2.0 m/s.In the 60 deg S - 60 deg N region, about 50% of the daily F8 and F10 wind speed differences was caused by measurement non-simultaneity and about 50% of the difference was attributed to other factors, such as instrument noise and the different azimuthal orientations of each SSMI.

Halpern, David↗
NASA NTRS1998

Using Sequential Earth Images to Determine the Orientation of a Satellite at L1

This paper introduces a method for determining the three-axis attitude (orientation) of a spacecraft from a sequence of Earth images taken while in orbit about the stationary Lagrange point between the Earth and the sun (LI). Two axes of information can be obtained simply by monitoring the Earth's position within the field-of-view of the camera. The third axis is obtained by correlating sequential Earth images in such a way as to detect the flow of the features within the Earth's disk over time. When taken correctly, this measurement is perpendicular to the Earth's spin axis and, consequently, locates the Earth's spin axis within the images. This is equivalent to determining the orientation of the spacecraft about the instrument's boresight. Actual data from the Galileo spacecraft is used to test the algorithms outlined in this paper.

Houghton, Martin B.↗
NASA NTRS2001

Systematic Differences Between Radiosonde Instruments

Deviations of radiosonde reports' geopotential heights from the zonal mean are examined. In the summer Northern Hemisphere stratosphere, systematic differences are found between radiosonde instrument types. Persistent meridional wind anomalies, approximately constant in magnitude and fixed in location, have previously been reported in the summer stratosphere, and one such anomaly over Europe is found to be co-located with boundaries between regions in which differing types of radiosonde instruments are used. The magnitude and orientation of the radiosonde geopotential height biases are consistent with the wind anomalies. Because the overall winds tend to be light in this region and season, these wind anomalies can represent significant perturbations of the flow and must be considered when interpreting the results of trajectory and diagnostic studies.

Lait, Leslie R.↗
NASA NTRS2004

A space radiation shielding model of the Martian radiation environment experiment (MARIE)

The 2001 Mars Odyssey spacecraft was launched towards Mars on April 7, 2001. Onboard the spacecraft is the Martian radiation environment experiment (MARIE), which is designed to measure the background radiation environment due to galactic cosmic rays (GCR) and solar protons in the 20-500 MeV/n energy range. We present an approach for developing a space radiation-shielding model of the spacecraft that includes the MARIE instrument in the current mapping phase orientation. A discussion is presented describing the development and methodology used to construct the shielding model. For a given GCR model environment, using the current MARIE shielding model and the high-energy particle transport codes, dose rate values are compared with MARIE measurements during the early mapping phase in Mars orbit. The results show good agreement between the model calculations and the MARIE measurements as presented for the March 2002 dataset. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

NASA Center JSC↗
NASA NTRS1995

Optoelectronic Inclinometer

Proposed optoelectronic instrument measures tilt of object about single horizontal axis by measuring change of position and orientation of laser beam reflected from hanging mirror. Mirror remains vertical while rest of instrument rotated with object. Optoelectronic inclinometer measures tilt about gimbal axis by measuring change in position and orientation of beam of light reflected from mirror hanging in gimbal. Maximum amount of tilt about pivot axis of pendulum that instrument tolerates depends on size of mirror and physical size of linear array and spacing of components. Compensating lens included to correct for nonlinearity and to ensure that beam continued to fall on array throughout desired angular range of instrument.

Schott, Timothy D.↗
NASA NTRS1982

Data and data retrieval in space astronomy

To illustrate the range of storage and retrieval facilities and data products that are involved in space astronomy, the present situation on data from some instruments on the following missions is presented: Small Astronomy Satellite-B, Orbiting Astronomical Observatory 3, High Energy Astrophysics Observatory 2, International Ultraviolet Explorer, Viking Orbiter, and Solar Maximum Mission. In addition, the Coordinated Data Analysis Workshops conducted at the National Space Science Data Center are outlined to demonstrate the usefulness of building a problem-oriented on-line data base from instruments flown on a number of spacecraft and operating from ground-based facilities.

Vette, J. I.↗
NASA NTRS1993

Hollow Retroreflectors

A hollow retroreflector is a mirror-like instrument that reflects light and other radiations back to the source. After developing a hollow retroreflector for NASA's Apollo-Soyuz mission, PLX, Inc. continued to expand the technology and develop a variety of retroreflector systems. The Lateral Transfer Hollow Retroreflector maintains precise separation, at any wavelength, of incoming and existing beams regardless of their orientation. It can be used as an instrument or as a component of an optical system. In the laboratory, it offers a new efficient means of beam positioning. In other applications, it connects laser resonators, aligns telescope mirrors and is useful in general boresighting and alignment.

Source record↗
NASA NTRS2013

Science Opportunity Analyzer (SOA) Version 8

SOA allows scientists to plan spacecraft observations. It facilitates the identification of geometrically interesting times in a spacecraft s orbit that a user can use to plan observations or instrument-driven spacecraft maneuvers. These observations can then be visualized multiple ways in both two- and three-dimensional views. When observations have been optimized within a spacecraft's flight rules, the resulting plans can be output for use by other JPL uplink tools. Now in its eighth major version, SOA improves on these capabilities in a modern and integrated fashion. SOA consists of five major functions: Opportunity Search, Visualization, Observation Design, Constraint Checking, and Data Output. Opportunity Search is a GUI-driven interface to existing search engines that can be used to identify times when a spacecraft is in a specific geometrical relationship with other bodies in the solar system. This function can be used for advanced mission planning as well as for making last-minute adjustments to mission sequences in response to trajectory modifications. Visualization is a key aspect of SOA. The user can view observation opportunities in either a 3D representation or as a 2D map projection. Observation Design allows the user to orient the spacecraft and visualize the projection of the instrument field of view for that orientation using the same views as Opportunity Search. Constraint Checking is provided to validate various geometrical and physical aspects of an observation design. The user has the ability to easily create custom rules or to use official project-generated flight rules. This capability may also allow scientists to easily assess the cost to science if flight rule changes occur. Data Output allows the user to compute ancillary data related to an observation or to a given position of the spacecraft along its trajectory. The data can be saved as a tab-delimited text file or viewed as a graph. SOA combines science planning functionality unique to both JPL and the sponsoring spacecraft. SOA is able to ingest JPL SPICE Kernels that are used to drive the tool and its computations. A Percy search engine is then included that identifies interesting time periods for the user to build observations. When observations are then built, flight-like orientation algorithms replicate spacecraft dynamics to closely simulate the flight spacecraft s dynamics. SOA v8 represents large steps forward from SOA v7 in terms of quality, reliability, maintainability, efficiency, and user experience. A tailored agile development environment has been built around SOA that provides automated unit testing, continuous build and integration, a consolidated Web-based code and documentation storage environment, modern Java enhancements, and a focus on usability

Witoff, Robert J.↗
NASA NTRS1994

Propagating orientation constraints for the Hubble Space Telescope

An observing program on the Hubble Space Telescope (HST) is described in terms of exposures that are obtained by one or more of the instruments onboard the HST. Many requested exposures might specify orientation requirements and accompanying ranges. Orientation refers to the amount of roll (in degrees) about the line of sight. The range give the permissible tolerance (also in degrees). These requirements may be (1) absolute (in relation to the celestial coordinate system), (2) relative to the nominal roll angle for HST during that exposure, or (3) relative (in relation to other exposures in the observing program). The TRANSformation expert system converts proposals for astronomical observations with HST into detailed observing plans. Part of the conversion involves grouping exposures into higher level structures based on exposure characteristics. Exposures constrained to be at different orientations cannot be grouped together. Because relative orientation requirements cause implicit constraints, orientation constraints have to be propagated. TRANS must also identify any inconsistencies that may exist so they can be corrected. We have designed and implemented an orientation constraint propagator as part of TRANS. The propagator is based on an informal algebra that facilitates the setting up and propagation of the orientation constraints. The constraint propagator generates constraints between directly related exposures, and propagates derived constraints between exposures that are related indirectly. It provides facilities for path-consistency checking, identification of unsatisfiable constraints, and querying of orientation relationships. The system has been successfully operational as part of TRANS for over seven months. The solution has particular significance to space applications in which satellite/telescope pointing and attitude are constrained and relationships exist between multiple configurations.

Bose, Ashim↗
NASA NTRS1992

C++, objected-oriented programming, and astronomical data models

Contemporary astronomy is characterized by increasingly complex instruments and observational techniques, higher data collection rates, and large data archives, placing severe stress on software analysis systems. The object-oriented paradigm represents a significant new approach to software design and implementation that holds great promise for dealing with this increased complexity. The basic concepts of this approach will be characterized in contrast to more traditional procedure-oriented approaches. The fundamental features of objected-oriented programming will be discussed from a C++ programming language perspective, using examples familiar to astronomers. This discussion will focus on objects, classes and their relevance to the data type system; the principle of information hiding; and the use of inheritance to implement generalization/specialization relationships. Drawing on the object-oriented approach, features of a new database model to support astronomical data analysis will be presented.

Farris, A.↗
NASA NTRS1983

VISSR Atmospheric Sounder (VAS) Research Review

The VAS, an experimental instrument flown onboard Geostationary Operational Environmental Satellite (GOES), is capable of achieving mutlispectral imagery of atmospheric temperature, water vapor, and cloudiness patterns over short time intervals. In addition, this instrument provides an atmospheric sounding capability from geosynchronous orbit. The VAS demonstration is an effort for evaluating the VAS instrument's performance, and for demonstrating the capabilities of a VAS prototype system to provide useful geosynchronous satellite data for supporting weather forecasts and atmospheric research. The demonstration evaluates the performance of the VAS Instruments on GOES-4-5, and -6, develops research oriented and prototype/operational VAS data processing systems, determines the accuracy of certain basic and derived meteorological parameters that can be obtained from the VAS instrument, and assesses the utility of VAS derived information in analyzing severe weather situations.

Greaves, J. R.↗