Large Area Crop Inventory Experiment (LACIE). Signature extension in remote sensing
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Chittineni, C. B.↗
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Space shuttle orbiter trimmed center-of-gravity extension study. Volume 5: Effects of configuration modifications on the aerodynamic characteristics of the 140A/B orbiter at Mach numbers of 2.5, 3.95 and 4.6
Supersonic aerodynamic characteristics are presented for the 140A/B space shuttle orbiter configuration (0.010 scale) and for the configuration modified to incorporate geometry changes in the wing planform fillet region. The modifications designed to extend the orbiter's longitudinal trim capability to more forward center-of-gravity locations, included reshaping of the baseline wing planform fillet and adding canards. The investigation was made in the high Mach number test section of the Langley Unitary Plan Wind Tunnel at a Reynolds number of approximately 2.2 million based on fuselage reference length. The angle-of-attack range for the investigation extended from -1 deg to 31 deg. Data were obtained with the elevators and body flap deflected at appropriate negative and positive conditions to assess the trim limits.
Phillips, W. P.↗
Improvement and extension of data from ATS-6 Solar Cell Radiation Damage Experiment (SCRDE)
The ATS 6 solar cell radiation damage experiment data through 2 1/3 years of synchronous orbit operation are presented. Comparisons are made of the performances of the 13 different types of solar cell/cover configurations, including solar cell and cover thickness variations, base resistivity variation, new cover processes and materials, and the COMSAT violet cell. These performances are also compared to the performance of the LES 6 solar cell experiment, the ATS 6 main solar arrays, and laboratory spectrum electron irradiations. It is found that the cells of the ATS 6 experiment generally performed as expected through 6 to 9 months in orbit, but that at 2 1/3 years they were severely degraded in current. The short circuit current degradation after 2 1/3 years in orbit appears to exhibit an anomalous additional degradation of 5 to 9 percent over what was experienced in synchronous orbit operation.
Goldhammer, L. J.↗
An extension of MacCormack's method for flows with higher-order equations and in different configurations
The numerical scheme for the computation of a shock discontinuity developed by MacCormack has been extended to solve a number of differential equations, including cases explicitly containing higher-order derivatives: (1) Korteweg-de Vries equation with a term of third-order derivative, (2) a system of nonlinear equations governing nonsteady one-dimensional plasma flow in cylindrical coordinate, (3) equations of solar wind. Comparisons with previous results are made, if available, to illustrate the advantages of the present method. The question of convergence of the numerical calculation is discussed.
Ying, S. J.↗
Extensions of the Wilson-Bappu effect among very luminous stars
It has been stated that the technique used by Wilson and Bappu (1957) in their study of the observational correlation of M sub V and the logarithm of the full width at half maximum of the Ca II K-line central emission for G, K, and M stars has a plus or minus 0.5 mag accuracy. A tabulation by Wilson (1976) suggests, however, that the error may be only plus or minus 0.3 mag. This accuracy makes the approach valuable for late-type supergiants since other methods suffer from comparable errors. A description is in this connection presented of a new class of emission lines in late-type giant and supergiant spectra that exhibit M sub V correlated widths, yet are detectable among the brightest stars.
Stencel, R. E.↗
The computation of incompressible, three-dimensional flows in containers with extensible walls
The theoretical study of flow in biological vascular systems is made very difficult in connection with local and temporal changes of the cross section. Experimental investigations with the aid of model tests are, however, not enough for a solution of the problems, and numerical solutions are more and more employed for a description of such flows. A description is presented of a difference procedure for the solution of the complete Navier-Stokes equations with curvilinear coordinates for three-dimensional flows in containers. The integration of the Navier-Stokes equations for flows in containers with rigid and moving walls is considered.
Liu, N. S.↗
Extensive cost reduction studies: Composite empennage component - L-1011 commercial airliner
A series of cover skin laminate studies was conducted. The baseline laminate design is composed of 34 plies with doublers interwoven. This is costly to produce, since the broad goods tape dispersing machine must stop frequently while the doubler plies are inserted by hand during the layup sequence. The use of graphite cloth was investigated for the cover skin. Attention is also given to low resin content prepreg, the selection of optimum tape width, an increase in gap/overlap tolerances, the use of large reusable vacuum bags with mechanical edge seals for production, an integrated laminating center machine, automated hat stiffener processing, a secondary bond assembly process, and a single-stage cure process.
Van Hamersveld, J.↗
Approximations for proton excitation - Erratum and extension
Kastner (1977) proposed relatively simple approximations for proton excitation in coronal ions, which yield both excitation rate coefficients and excitation cross sections. An error in Kastner's expression for one of the partial excitation rate coefficients is corrected. The expression for excitation cross section is extended to higher energies, and the resulting expression for the other partial rate coefficient is given. Results obtained with the corrected and extended total excitation rate coefficient are presented for several representative transitions in Ca XIII, Ca XV, Fe X, Fe XIII, Fe XIV, Fe XVIII, and S X. The corrected and extended approximation is expected to yield excitation rates reliably within 50%.
Kastner, S. O.↗
Extension of the coherence function to quadratic models
It is shown how the use of higher coherence functions can recover some of the lost coherence due to nonlinear relationship between two fluctuating quantities whose degree of mutual coherence is being measured. The relationship between the two processes is modeled with the aid of a linear term and a quadratic term. As a specific example, the relationship between plasma density and potential fluctuations in a plasma is considered. The fraction of power in the auto-power spectrum of the potential fluctuations due to a linear relationship and to a quadratic relationship between the density and potential fluctuations is estimated.
Kim, Y. C.↗
Far-infrared observations of optical emission-line stars - Evidence for extensive cool dust clouds
Far-infrared observations (40-160 microns) of eight optical emission-line stars are presented. Six of these stars, LkH-alpha 198, T Tau, LkH-alpha 101, V380 Ori, R Mon, and MWC 1080, show substantially more far-infrared emission than would be expected on the basis of a blackbody extrapolation of their 10-20-micron fluxes. Additionally, in three cases, the far-infrared emission is shown to be spatially extended (greater than 40 arcsec). A simple model of the thermal emission from cool circumstellar dust (30-70 K) shows that these stars are surrounded by material left over from the star formation process; this result confirms the extreme youth of these stars. MWC 349 was detected at a level consistent with the expected free-free flux from its surrounding H II region, and RY Tau was not detected in the far-infrared; there is little circumstellar dust with temperatures of 20-100 K in these objects.
Harvey, P. M.↗
Extension of a theorem used in the investigation of P-N junctions with the scanning electron microscope to arbitrary geometries and arbitrarily inhomogeneous material
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Von Roos, O.↗
Orbital Transfer Vehicle (OTV) engine study. Phase A: Extension
An orbital transfer vehicle OTV engine study program was undertaken to provide additional expander and staged combustion cycle data in the design definition of the OTV engine. The proposed program effort optimizes the expander cycle engine concept (consistent with identified OTV engine requirements), investigates the feasibility of kitting the staged combustion cycle engine to provide extended low thrust operation, and conducts in-depth analysis of development risk, crew safety, and reliability for both cycles. Additional tasks to establish the cost of a 10K thrust expander cycle engine and to render support of OTV systems study contractors are reported.
Sobin, A. J.↗
Development of partitioning as an aid to spectral signature extension
Lists of spectrally similar LACIE sample segments may be constructed with the use of three basic information types: static, seasonal, and pass-specific variables. All are related directly or indirectly to spectral signature behavior and can be used to define spatial domains over which crop-specific signatures should be extendable. Topics covered include: (1) static spectral stratification; (2) evaluation of static partitions relative to variance control objectives; (3) evaluation of the relative importance of static versus seasonal and pass-specific partitioning variables in spectral variability; and (4) a current perspective on partitioning.
Thomas, R. W.↗
Extension of similarity test procedures to cooled engine components with insulating ceramic coatings
Material thermal conductivity was analyzed for its effect on the thermal performance of air cooled gas turbine components, both with and without a ceramic thermal-barrier material, tested at reduced temperatures and pressures. The analysis shows that neglecting the material thermal conductivity can contribute significant errors when metal-wall-temperature test data taken on a turbine vane are extrapolated to engine conditions. This error in metal temperature for an uncoated vane is of opposite sign from that for a ceramic-coated vane. A correction technique is developed for both ceramic-coated and uncoated components.
Gladden, H. J.↗
Orbit transfer vehicle engine study, phase A extension. Volume 1: Executive summary
A 1980 state-of-the-art advanced expander engine was configured that delivers near-optimum payload-performance and exhibits the simplicity reliability, and life characteristics required of the OTV mission. Engine optimization studies indicate that the performance of the conventional expander cycle engine can be improved substantially through combustion chamber surface area enhancement, thermal enhancement, turbine regeneration, and power cycle efficiency enhancement procedures. The 20K lb. thrust staged combustion engine can be adapted to operate at extended periods in the 1 to 2K lb. thrust regime. The study results indicate that long-life, high performnce operation in the low thrust mode can be achieved with minimum modifications (kitting) of the engine. Although the main contribution to mission success and crew safety stems from propulsion system redundancy, significant reliability can be gained from engine component redundancy, specific engine design features ensuring safety and reliability, including an engine health monitoring system, and from a total program approach to safety and reliability, such as that presently applied to the space shuttle.
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Orbit transfer vehicle engine study, phase A extension. Volume 2A: Study results
Engine trade studies and systems analyses leading to a baseline engine selection for advanced expander cycle engine are discussed with emphasis on: (1) performance optimization of advanced expander cycle engines in the 10 to 20K pound thrust range; (2) selection of a recommended advanced expander engine configuration based on maximized performance and minimized mission risk, and definition of the components for this configuration; (3) characterization of the low thrust adaptation requirements and performance for the staged combustion engine; (4) generation of a suggested safety and reliability approach for OTV engines independent of engine cycle; (5) definition of program risk relationships between expander and staged combustion cycle engines; and (6) development of schedules and costs for the DDT&E, production, and operation phases of the 10K pound thrust expander engine program.
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Orbiting X-ray observatory earns mission extension
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Orbit Transfer Vehicle (OTV) engine phase A study, extension 1. Volume 3: Study cost estimates
Program cost and planning data based on 1980 technology and shown in 1979 dollars for a 20K lb Thrust Staged Combustion Cycle Engine are presented. These data were compared with those for the Advanced Expander Cycle Engine at 10K lb and 20K lb thrust levels.
Christensen, K. L.↗