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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 181 records · Page 10
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NASA NTRS1974

Image data processing of earth resources management

The Earth Resources Technology Satellite (ERTS-1) was launched on July 23, 1972. Since that date, the vehicle has been acquiring and transmitting to earth a vast amount of information relating to the earth's resources. Scientific investigators throughout the world have been analyzing photographic products produced from this data with significant results. Recently, there has been a major shift of emphasis from the visual analysis of photo products to the use of sophisticated digital information extraction techniques. Specialized equipment, such as the GE IMAGE 100 System, has been developed that operates directly from Computer Compatible Tapes, (CCT’s), which contain preprocessed digital data acquired from the ERTS spacecraft. Analysis of CCT data avoids the losses in image resolution and quality which are inherent to all photo processing techniques, thereby greatly increasing the utility of ERTS data. Future ground processing systems will turn out fully corrected (radiometric and geometric) digital tapes which will further increase the utility of ERTS data. This paper is presented in two parts: the first part deals with the subject of present and future generations of image processing and information extraction systems under development at the General Electric Company; the second part describes in more detail the design and operation of GE1s interactive multispectral information extraction systems, IMAGE 100, and discusses results of analyses of ERTS data over a number of U.S. sites.

A W DeSio↗
NASA NTRS1974

MSFC Skylab ground-based astronomy program

The Skylab Ground-Based Astronomy Program (SGAP) was conducted to enhance the data base of solar physics obtained during the Apollo Telescope Mount (ATM) mission flown in conjunction with the Skylab orbital station. Leading solar physicists from various observatories obtained data from the ground at the same time that orbital data were being acquired by ATM. The acquisition of corollary solar data from the ground simultaneously with the ATM orbital observations helped to provide a broader basis for understanding solar physics by increasing spectral coverage and by the use of additional sophisticated instruments of various types. This report briefly describes the individual tasks and the associated instrumentation selected for this ground-based program and contains as appendices, the final reports from the Principal Investigators.

Duncan, B. J.↗
NASA NTRS1975

Fabrication and evaluation of an OSO-1 type baseplate

An OSO-1 type baseplate of a low thermal-expansion glass-ceramic material was evaluated for its dimensional stability after exposure to thermal cycling and mechanical vibration. The results indicate that baseplates of relatively simple design can be successfully cast and machined, although the demonstration article produced deviated somewhat from design specifications. It is likely that baseplates of more sophisticated designs and improved structural efficiency also can be prepared from low thermal expansion material.

Marschall, C. W.↗
NASA NTRS1974

Repair of major system elements on Skylab

In-flight maintenance, as conceived and preplanned for the Skylab mission was limited to simple scheduled and unscheduled replacement tasks and minor contingency repairs. Tools and spares were provided accordingly. However, failures during the mission dictated complicated and sophisticated repairs to major systems so that the mission could continue. These repairs included the release of a large structure that failed to deploy, the assembly and deployment of large mechanical devices, the installation and checkout of precision electronic equipment, troubleshooting and repair of precision electromechanical equipment, and tapping into and recharging a cooling system. The repairs were conducted both inside the spacecraft and during extravehicular activities. Some of the repair tasks required team effort on the part of the crewmen including close procedural coordination between internal and extravehicular crewmen. The Skylab experience indicates that crewmen can, with adequate training, make major system repairs in space using standard or special tools. Design of future spacecraft systems should acknowledge this capability and provide for more extensive in-flight repair and maintenance.

Pace, R. E., Jr.↗
NASA NTRS1975

Planetary investigation utilizing an imaging spectrometer system based upon charge injection technology

An intrinsic silicon charge injection device (CID) television sensor array has been used in conjunction with a CaMoO4 colinear tunable acousto optic filter, a 61 inch reflector, a sophisticated computer system, and a digital color TV scan converter/computer to produce near IR images of Saturn and Jupiter with 10A spectral resolution and approximately 3 inch spatial resolution. The CID camera has successfully obtained digitized 100 x 100 array images with 5 minutes of exposure time, and slow-scanned readout to a computer. Details of the equipment setup, innovations, problems, experience, data and final equipment performance limits are given.

Wattson, R. B.↗
NASA NTRS1971

The relative effects of entry parameters on thermal protection system weight

Shielding a spacecraft from the severe thermal environment of an atmospheric entry requires a sophisticated thermal protection system (TPS). Thermal computer program models were developed for two such TPS designs proposed for the space shuttle orbiter. The multilayer systems, a reusable surface insulation TPS, and a re-radiative metallic skin TPS, were sized for a cross-section of trajectories in the entry corridor. This analysis indicates the relative influence of the entry parameters on the weight of each TPS concept. The results are summarized graphically. The trajectory variables considered were down-range, cross-range, orbit inclination, entry interface velocity and flight path angle, maximum heating rate level, angle of attack, and ballistic coefficient. Variations in cross-range and flight path angle over the ranges considered had virtually no effect on the required entry TPS weight. The TPS weight was significantly more sensitive to variations in angle of attack than to dispersions in the other trajectory considered.

Hirasaki, P. N.↗
NASA NTRS1975

Importance of helicopter dynamics to the mathematical model of the helicopter

A mathematical model of the helicopter requires appropriate representation of the constituent elements of rotor dynamics. General-purpose programs that model a variety of configurations for a broad range of operating conditions result in varying and incompatible levels of sophistication. Analysis of specific dynamic problems facilitates the identification of configuration parameters which determine system behavior. For the present analysis, the nonlinear equations of a torsionally rigid hingeless rotor are linearized about an equilibrium condition to determine flap-lag stability characteristics in hover. A collocation method was used to obtain the coupled natural frequencies and modes. These modes allow exact treatment of the effect of elastic coupling which more than compensates for the destabilizing inertial coupling. The sensitivity of damping to the number of modes was found to be small, and reasonable accuracy was obtained the first flapwise and edgewise coupled modes. The range of destabilizing precone was found to be small.

White, W. F., Jr.↗
NASA NTRS1975

Results of a flight investigation of control-display interactions for VTOL decelerating descending instrument approaches using the X-22A aircraft

Control, display, and guidance requirements for VTOL instrument transitions were studied to provide meaningful data related to the interaction of aircraft control system and pilot display characteristics on pilot rating and performance during a steep decelerating descending transition from a representative forward velocity to the hover under simulated instrument conditions. Thirty seven evaluations were performed of combinations of five generic display presentations, ranging from position information only to four axis control directors, and five levels of control augmentation systems, ranging from rate augmentation only to decoupled velocity responses and automatic configuration changes. Primary results include the demonstration of an inverse relationship between control complexity and display sophistication and the definition of acceptable and satisfactory control display combinations.

Lebacqz, J. V.↗
NASA NTRS1975

A simulator study on information requirements for precision hovering

A fixed base simulator study of an advanced helicopter instrument display utilizing translational acceleration, velocity and position information is reported. The simulation involved piloting a heavy helicopter using the Integrated Trajectory Error Display (ITED) in a precision hover task. The test series explored two basic areas. The effect on hover accuracy of adding acceleration information was of primary concern. Also of interest was the operators' ability to use degraded information derived from less sophisticated sources. The addition of translational acceleration to a display containing velocity and position information did not appear to improve the hover performance significantly. However, displayed acceleration information seemed to increase the damping of the man machine system. Finally, the pilots could use translational information synthesized from attitude and angular acceleration as effectively as perfect acceleration.

Lemons, J. L.↗
NASA NTRS1974

Semiclassical S-matrix theory of vibrationally inelastic collisions between two diatomic molecules

We derive a semiclassical S matrix for vibrationally inelastic collisions between two diatomic molecules, assuming a collinear geometry. Our theory incorporates a quantum mechanical superposition principle with classical dynamics and, as such, is an extension of the atom-diatomic molecule theory of Miller. The several approximations to the S matrix differ in the complexity with which the interference between various classical trajectories is treated. We report numerical calculations for H2-D2 and D2-D2 collisions based on two different interaction potentials. The cruder approximations yield transition probabilities which agree with exact quantum mechanical results to within a factor of 2. More sophisticated approximations to the S matrix yield excellent quantitative agreement with the quantum calculations.

Cohen, S. C.↗
NASA NTRS1974

Simultaneous master-slave Omega pairs

Master-slave sequence ordering of the Omega system is suggested as a method of improving the pair geometry for low-cost receiver user benefit. The sequence change will not affect present sophisticated processor users other than require new labels for some pair combinations, but may require worldwide transmitter operators to slightly alter their long-range synchronizing techniques.

Burhans, R. W.↗
NASA NTRS1974

Atom movements occurring at solid metal-semiconductor interfaces

Solid metal-semiconductor interfaces often undergo chemical reaction at rather low temperatures, in some cases not much above room temperature. After some general discussion of these reactions, more detailed consideration is given to simple noncompound-forming systems, and, in particular, to the Si-Al, Ge-Al, and Si-Au systems. Diffusive transport of Si or Ge in these solid metallizations is very rapid, though the converse process, diffusion of metal in solid Si or Ge, is usually so slow as to be negligible. The interface reaction itself is less well understood but is becoming controllable in intrinsically favorable cases like Ge-Al and in other cases by more sophisticated means.

Mccaldin, J. O.↗
NASA NTRS1974

Experiments in determining the outgassing of spacecraft in the vacuum environment

As spacecraft become more sophisticated, their contamination becomes of increasing concern. The use of real-time monitors, such as the quartz crystal microbalance, and post-test methods such as the chemical analysis of residuals, has been combined with a number of analytical techniques in contamination-related investigations at the Goddard Space Flight Center. These include the establishment of the cause of an orbital failure, the determination of component outgassing rates, and the monitoring of contaminants in vacuum chambers and in orbit. Improved capabilities appear possible with measurement methods such as attenuated total reflectance and better analytical modeling of the contaminant flux environment.

Kruger, R.↗
NASA NTRS1975

The Pioneer 10/11 and Helios A/B cosmic ray instruments

This paper describes the design and performance of a set of cosmic-ray particle experiments for the Pioneer 10/11 and Helios A/B space missions. These experiments had to be very light-weight, low-power and electronically sophisticated in order to meet the spacecraft and scientific requirements. Both sets of missions use several solid-state detector telescopes to measure protons from 100 KeV to 800 MeV and heavier ions up to Neon at 200 MeV per nucleon. Good performance is required for 7-8 years, and the system must tolerate large vibration loads and ionizing radiation doses up to 500,000 rads.

Stilwell, D. E.↗
NASA NTRS1975

Repair of major system elements on Skylab

In-flight maintenance, as conceived and pre-planned for the Skylab Mission, was limited to simple scheduled and unscheduled replacement tasks and minor contingency repairs. Failures during the mission dictated complicated and sophisticated repairs to major systems so that the mission could continue. These repairs include the release of a large structure that failed to deploy, the assembly and deployment of large mechanical devices, the installation and checkout of precision electronic equipment, troubleshooting and repair of precision electromechanical equipment and tapping into and recharging a cooling system. The Skylab experience proves conclusively that crewmen can, with adequate training, make major system repairs in space using standard or special tools.

Pace, R. E., Jr.↗
NASA NTRS1975

Thermospheric composition

The global view of the atmosphere provided by satellite observations and radar backscatter measurements has shown a pattern of composition variability resulting largely from dynamic processes. Important progress has been made in defining composition variability at 120 km, which has greatly improved models which previously had fixed boundary conditions at that altitude. The discovery of the early morning maximum in helium abundance and the better definition of diurnal variation in relative composition have provided a basis for more sophisticated dynamical models. Similarly, models of meridional wind systems have been developed which can account for the better-defined winter enhancements in helium and atomic oxygen. Finally, composition variability has indicated the presence of a high-latitude heat source which during periods of magnetic activity profoundly modifies the state of the atmosphere.

Carignan, G. R.↗
NASA NTRS1975

High-resolution system for tropospheric wind and temperature profile measurements

This paper briefly describes the Jimsphere/Jimsonde system and presents some possible applications of the system. As space vehicles became larger and more sophisticated, an improved method for obtaining wind-profile data had to be found. To satisfy this need, the FPS-16 radar/Jimsphere system was developed. The Jimsphere is an aluminized mylar spherical balloon 2 m in diameter. The balloon is under superpressure and is tracked with a high-precision radar system. The development of this detailed wind-profile system was started in 1963, and the present design was established in 1964. To improve the system, a program was initiated in 1965 to obtain high-resolution temperature data simultaneously with the wind-profile data.

Camp, D. W.↗
NASA NTRS1975

NECAP: NASA's Energy-Cost Analysis Program. Part 1: User's manual

The NECAP is a sophisticated building design and energy analysis tool which has embodied within it all of the latest ASHRAE state-of-the-art techniques for performing thermal load calculation and energy usage predictions. It is a set of six individual computer programs which include: response factor program, data verification program, thermal load analysis program, variable temperature program, system and equipment simulation program, and owning and operating cost program. Each segment of NECAP is described, and instructions are set forth for preparing the required input data and for interpreting the resulting reports.

Henninger, R. H.↗