Search NASA⌕ Search

SEARCH · Search NASA

Results for “OPERATIONAL PROBLEM”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Unlimbering Viking's scoop

A number of difficulties which were encountered in deploying the Viking 1 lander's surface-sampler arm are discussed. When the surface sampler jammed during its initial operation, the problem was studied with the aid of tests on a full-scale lander mock-up. It was found that the difficulty was caused by a boom latch pin which had failed to fall clear. The surface-sampler arm could subsequently be freed by modifying the original command sequence. Another difficulty could be overcome by a similar approach.

Spitzer, C. R.↗
NASA NTRS1978

The LPSP instrument on OSO 8. II - In-flight performance and preliminary results

The paper describes the in-flight performance for the first 18 months of operation of the LPSP (Laboratoire de Physique Stellaire et Planetaire) instrument incorporated in the OSO 8 launched June 1975. By means of the instrument, an absolute pointing accuracy of nearly one second was achieved in orbit during real-time operations. The instrument uses a Cassegrain telescope and a spectrometer simultaneously observing six wavelengths. In-flight performance is discussed with attention to angular resolution, spectral resolution, dispersion and grating mechanism (spectral scanner) stability, scattered light background and dark current, photometric standardization, and absolute calibration. Real-time operation and problems are considered with reference to pointing system problems, target acquisition, and L-alpha modulation. Preliminary results involving the observational program, quiet sun and chromospheric studies, quiet chromospheric oscillation and transients, sunspots and active regions, prominences, and aeronomy investigations are reported.

Bonnet, R. M.↗
NASA NTRS1981

Satellite altimetric measurements of the ocean. Report of the TOPEX Science Working Group

The scientific usefulness of satellite measurements of ocean topography for the study of ocean circulation was investigated. The following topics were studied: (1) scientific problems which use altimetric measurements of ocean topography; (2) the extent in which in situ measurements are complementary or required; (3) accuracy, precision, and spatial and temporal resolutions which are required of the topographic measurements; (4) errors associated with measurement techniques; and (5) influences of these errors on scientific problems. An operational system for measuring ocean topography, was defined and the cost of conducting such a topographic experiment, was estimated.

Stewart, R.↗
NASA NTRS1981

Boresighting techniques for the Antenna Control Assembly (ACA)

Comparison of four scanning schemes including CONSCAN indicates that CONSCAN with signal cleanup and protection processes has the greatest merit in terms of accuracy, dependability and automatic unattended operation. Specific problem areas, error sources, and corrective measures are discussed.

Abichandani, K. P.↗
NASA NTRS1981

Mapping of submerged vegetation using remote sensing technology

Techniques for mapping submerged sea grasses using aircraft supported remote sensors are described. The 21 channel solid state array spectroradiometer was successfully used as a remote sensor in the experiment in that the system operated without problem and obtained data. The environmental conditions of clear water, bright sandy bottom and monospecific vegetation (Thalassia) were ideal.

Savastano, K. J.↗
NASA NTRS1981

Space transportation - Reflections and projections

The history of U.S. manned spaceflight and the vehicles used is discussed. The programs began with low budgets and handwritten charts, then proceeded through the Redstone Mercury launch in 1961 and the Atlas Mercury orbital mission in 1962, with the decision to begin the Apollo project coming between those flights. Use of a sole source procurement with a nonprofit institution like the MIT Draper Laboratory for the Apollo guidance system is noted to have expedited the speed of paperwork. A lunar orbital rendezvous was chosen in October 1962 for the Saturn CV-launched Apollo. The Gemini capsule, eliminated early as a lunar module, served to expose problems of operation in a zero-g environment. The benefits of humans in space were made apparent in the process of fixing the Skylab solar panels. The Shuttle capabilities are reviewed, and the necessity for a vehicle for access and return from GEO is emphasized. Finally, attention is given to a single stage to orbit vehicle and launch systems for a Solar Power Satellite.

Disher, J. H.↗
NASA NTRS1986

Clip-On Extensometer

Flexural clamp eliminates problems of operator variability. Extensometer opens and closes like clothespin and placed easily on specimen. Dimensions of block specimen are 1 by 1 by 2.2 inches (2.54 by 2.54 by 5.59 centimeters). By constructing central flexure units of various widths, one adapts extensometer to handle specimens ranging from thin strips to those many inches thick. New design reduces measurement errors caused by variability among test operators.

Holmes, A. M. C.↗
NASA NTRS1987

Utilization of Global Reference Atmosphere Model (GRAM) for shuttle entry

At high latitudes, dispersions in values of density for the middle atmosphere from the Global Reference Atmosphere Model (GRAM) are observed to be large, particularly in the winter. Trajectories have been run from 28.5 deg to 98 deg. The critical part of the atmosphere for reentry is 250,000 to 270,000 ft. 250,000 ft is the altitude where the shuttle trajectory levels out. For ascending passes the critical region occurs near the equator. For descending entries the critical region is in northern latitudes. The computed trajectory is input to the GRAM, which computes means and deviations of atmospheric parameters at each point along the trajectory. There is little latitude dispersion for the ascending passes; the strongest source of deviations is seasonal; however, very wide seasonal and latitudinal deviations are exhibited for the descending passes at all orbital inclinations. For shuttle operations the problem is control to maintain the correct entry corridor and avoid either aerodynamic skipping or excessive heat loads.

Joosten, Kent↗
NASA NTRS1987

A more perfect vacuum

Design and operational features, problems and benefits of a Space Ultravacuum Research Facility (SURF), a wake shield, are discussed. SURF is primarily targeted at providing vacuums exceeding 10 to the -14th torr for performing materials processing experiments and, eventually, commercial-scale production. The materials to be processed would be at the apex of a convex shield, with the quality of vacuum limited mainly by the backscattering toward the wake surface of atmospheric molecules which have collided with molecules leaving the SURF surface. A stainless steel skin on the SURF, cured in orbit, is proposed as a means to minimize the molecules outgassed from the surface. Applications of SURF could include coating mirrors or other optical equipment, containerless melting and solidification of materials, and ultrapurification processing.

Naumann, Robert J.↗
NASA NTRS1986

Vacuum pumps and systems: A review of current practice

A review of the fundamental characteristics of the many types of vacuum pumps and vacuum pumping systems is given. The optimum pumping range, relative cost, performance limitations, maintenance problems, system operating costs and similar subjects are discussed. Experiences from the thin film deposition, chemical processing, material handling, food processing and other industries, as well as space simulation are used to support conclusions and recommendations.

Giles, Stuart↗
NASA NTRS1989

Microparticle impacts in space: Results from Solar Max and shuttle witness plate inspections

The Solar Maximum Satellite developed electronic problems after operating successfully in space for several years. Astronauts on Space Shuttle mission STS-41C retrieved the satellite into the orbiter cargo bay, replaced defective components, and re-deployed the repaired satellite into orbit. The defective components were returned to Earth for study. The space-exposed surfaces were examined. The approach and objectives were to: document morphology of impact; find and analyze projectile residue; classify impact by origin; determine flux distribution; and determine implications for space exposure. The purpose of the shuttle witness plate experiment was to detect impacts from PAM D2 solid rocket motor; determine flux and size distribution of particles; and determine abrasion effects on various conditions. Results are given for aluminum surfaces, copper surfaces, stainless steel surfaces, Inconel surfaces, and quartz glass surfaces.

Mckay, David S.↗
NASA NTRS1989

The development of a Flight Test Engineer's Workstation for the Automated Flight Test Management System

The Automated Flight Test Management System (ATMS) is being developed as part of the NASA Aircraft Automation Program. This program focuses on the application of interdisciplinary state-of-the-art technology in artificial intelligence, control theory, and systems methodology to problems of operating and flight testing high-performance aircraft. The development of a Flight Test Engineer's Workstation (FTEWS) is presented, with a detailed description of the system, technical details, and future planned developments. The goal of the FTEWS is to provide flight test engineers and project officers with an automated computer environment for planning, scheduling, and performing flight test programs. The FTEWS system is an outgrowth of the development of ATMS and is an implementation of a component of ATMS on SUN workstations.

Tartt, David M.↗
NASA NTRS1992

The use of remotely sensed data for operational fisheries oceanography

Satellite remote sensing data are used under two contexts in fisheries: as a tool for fisheries research and as a means to provide operational support to fishing activities. Fishing operations need synoptic data provided timely; fisheries research needs that type of data and, also, good short-term climatologies. A description is given of several experiences conducted around the world which have employed or are using satellite data for operational fisheries problems. An overview is included of the Portuguese program for fisheries support using remotely sensed data provided by satellites and in situ observations conducted by fishermen. Environmental products useful for fisheries necessarily combine satellite and in situ data. The role of fishermen as a source of good, near-real-time in situ environmental data is stressed; so far, this role seems to have been largely overlooked.

Fiuza, Armando F. G.↗
NASA NTRS1991

NASA's program in lidar remote sensing

Several major NASA research efforts in lidar remote sensing are reviewed, with attention given to hardware and key sensor issues along with results and expectations. The discussion covers temperature and pressure measurements, measurements methods and instrumentation, pressure data, wind field measurements, atmospheric backscatter measurement, aerosol and cloud measurements, and water vapor measurement. Consideration is also given to the applicability of lidar measurements to problems of operational weather analysis and forecasting, climate studies, mesoscale and severe storm analysis and forecastig, and studies of atmosphere/surface interface.

Theon, John S.↗
NASA NTRS1992

Model-based reasoning in SSF ECLSS

The interacting processes and reconfigurable subsystems of the Space Station Freedom Environmental Control and Life Support System (ECLSS) present a tremendous technical challenge to Freedom's crew and ground support. ECLSS operation and problem analysis is time-consuming for crew members and difficult for current computerized control, monitoring, and diagnostic software. These challenges can be at least partially mitigated by the use of advanced techniques such as Model-Based Reasoning (MBR). This paper will provide an overview of MBR as it is being applied to Space Station Freedom ECLSS. It will report on work being done to produce intelligent systems to help design, control, monitor, and diagnose Freedom's ECLSS. Specifically, work on predictive monitoring, diagnosability, and diagnosis, with emphasis on the automated diagnosis of the regenerative water recovery and air revitalization processes will be discussed.

Miller, J. K.↗
NASA NTRS1951

Pilot Escape from Spinning Airplanes as Determined from Free-spinning-tunnel Tests

Procedure for pilot escape from spinning airplanes has been determined by means of tests in which pilot escape was simulated from 21 airplane models spinning in the Langley 20-foot free-spinning tunnel. The results in general indicated that the pilot should bail out of the outboard side. Calculated centripetal accelerations acting on the pilot during a spin are presented.

SAFETY - PILOT ESCAPE TECHNIQUES↗