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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Performance, emissions, and physical characteristics of a rotating combustion aircraft engine, supplement A

Testing was conducted using the basic RC2-75 engine, to which several modifications were incorporated which were designed to reduce the hydrocarbon emissions and reduce the specific fuel consumption. The modifications included close-in surface gap spark plugs, increased compression ratio rotors, and provisions for utilizing either side or peripheral intake ports, or a combination of the two if required. The proposed EPA emissions requirements were met using the normal peripheral porting. The specific fuel economy demonstrated for the modified RC2-75 was 283 g/kW-hr at 75% power and 101 brake mean effective pressure (BMEP) and 272.5 g/kW-hr at 75% power and 111 BMEP. The latter would result from rating the engine for takeoff at 285 hp and 5500 rpm, instead of 6000 rpm.

Lamping, R. K.↗
NASA NTRS1979

Early results from a prototype VLBI clock monitoring system

Four sets of experiments were conducted to measure the relative epoch offsets between atomic clocks in California, Australia, and Spain by means of very long baseline interferometry (VLBI). The experiments were conducted using an incomplete R & D VLBI system with a number of inherent limitations. The results indicate that the measurement objective of epoch offset to 10 nanoseconds will be met. Tables show the measured offset, the residual to fit, and the square root Allan variance. Graphs show the rate change and the rate reset.

Yunck, T. P.↗
NASA NTRS1980

Entry guidance and entry autopilot (STS-1 baseline)

Preliminary entry guidance and autopilot software formulations, for use in the Mission Control Center (MCC) entry processor, are presented. The MCC requirements are met by a definition of coordinate systems, a list of parameter definitions for the software formulations, a description of the entry guidance detailed formulation requirements, a description of the detailed autopilot formualtion requirements, a description of the targeting routine, and a set of formulation flow charts.

Harpold, J. C.↗
NASA NTRS1980

Solar energy system performance evaluation. Seasonal report for Colt Pueblo, Pueblo, Colorado

The Colt-Pueblo solar energy system, designed to provide space heating and hot water preheating, is described and its operational performance for a 12 month period from February 1979 through January 1980 is evaluated. The space heating subsystem met 31 percent of the measured space heating load which was close to the expected 34 percent solar fraction. Although the hot water solar fraction was 79 percent, the overall energy saving capability was reduced because of the low hot water demand. The measured heating subsystem performance would have improved considerably if the uncontrolled losses primarily from transport piping could have been reduced to an inconsequential level. Fossil energy savings of 70.31 million BTUs are estimated.

Source record↗
NASA NTRS1980

Solar energy system performance evaluation. Seasonal report for SEECO Lincoln, Lincoln, Nebraska

The Solar Engineering and Equipment Company (SEECO) Lincoln solar energy system, designed for space heating only, is described and its operational performance for a 12 month period from April 1979 through March 1980 is evaluated. The system met 27 percent of the space heating load; however, system losses into the heated space from the storage bin and ductwork were significant. Reducing these losses would add appreciably to the system's efficiency. Net fossil energy savings were 11.31 million BTUs.

Source record↗
NASA NTRS1980

Urban solar photovoltaics potential: An inventory and modelling study applied to the San Fernando Valley region of Los Angeles

Procedures for analyzing the potential of solar photovoltaic collectors to meet energy requirements in a metropolitan region are described and a modeling effort is applied to the San Fernando Valley region of Los Angeles. The procedure involves a series of steps designed to produce maps and tabulations revealing the amount of rooftop area available for establishing solar collectors and the proportion of energy requirement that could be potentially supplied by solar photovoltaics within each of the 533 mainline feeder service areas in the study area. For the sixty five square mile study area, the results showed that, with half the available flat and south facing roofs used and assuming the availability of energy storage, 52.7 percent of the actual kWh energy requirements could have been met in 1978 using photovoltaic collectors. Hourly, daily, weekly, and monthly fluctuations in potential supply and actual loads and recommendations of avenues for further research are discussed. Some further potential applications of the modeling technique are suggested.

Angelici, G. L.↗
NASA NTRS1980

Simulation development and evaluation of an improved longitudinal velocity vector control wheel steering mode and electronic display format

Using simulation, an improved longitudinal velocity vector control wheel steering mode and an improved electronic display format for an advanced flight system were developed and tested. Guidelines for the development phase were provided by test pilot critique summaries of the previous system. The results include performances from computer generated step column inputs across the full airplane speed and configuration envelope, as well as piloted performance results taken from a reference line tracking task and an approach to landing task conducted under various environmental conditions. The analysis of the results for the reference line tracking and approach to landing tasks indicates clearly detectable improvement in pilot tracking accuracy with a reduction in physical workload. The original objectives of upgrading the longitudinal axis of the velocity vector control wheel steering mode were successfully met when measured against the test pilot critique summaries and the original purpose outlined for this type of augment control mode.

Steinmetz, G. G.↗
NASA NTRS1980

Satellite power system (SPS) concept definition study. Volume 3: Experimental verification definition

An evolutionary Satellite Power Systems development plan was prepared. Planning analysis was directed toward the evolution of a scenario that met the stated objectives, was technically possible and economically attractive, and took into account constraining considerations, such as requirements for very large scale end-to-end demonstration in a compressed time frame, the relative cost/technical merits of ground testing versus space testing, and the need for large mass flow capability to low Earth orbit and geosynchronous orbit at reasonable cost per pound.

Hanley, G. M.↗
NASA NTRS1979

Viking adaptive mission sequence and control operations

Viking mission operations were required to provide an adaptive sequencing capability in which future observations could be influenced by the latest information about Mars as it was obtained and analyzed. The mission operations strategy that was developed met this requirement and provided the capability to respond smoothly and efficiently to spacecraft subsystem anomalies with minimum impact on the science data gathering process. A description of the major elements of this adaptive man-in-the-loop control system is provided. Specific cases showing how it was utilized to enhance scientific return and to respond to spacecraft anomalies are also provided.

Larman, B. T.↗
NASA NTRS1980

A new phase for NASA's communications satellite program

NASA's research in communications satellite technology is discussed, including orbit-efficient techniques and applications by the commercial sector. Attention is given to expanding the capacities of the C-band (6-4 GHz) and the Ku-band (14-11 GHz), opening the Ka-band (30/20 GHz), broadly applied 're-use' of the spectrum, and developing multibeam spacecraft antennas with on-board switching. Increasing wideband services in video, high-speed data, and voice trunking is considered, as are narrow-band systems that may be used for data collection or public safety, with possible expansion to a thin-route satellite system. In particular, communication for medical, disaster, or search-and-rescue emergencies may be met by the integration of a satellite service with land mobile communications via terrestrial radio links. Also considered is a large geostationary platform providing electrical power, thermal rejection, and orbital station-keeping for many communications payloads.

Dement, D. K.↗
NASA NTRS1979

Weight optimization of ultra large space structures

The paper describes the optimization of a solar power satellite structure for minimum mass and system cost. The solar power satellite is an ultra large low frequency and lightly damped space structure; derivation of its structural design requirements required accommodation of gravity gradient torques which impose primary loads, life up to 100 years in the rigorous geosynchronous orbit radiation environment, and prevention of continuous wave motion in a solar array blanket suspended from a huge, lightly damped structure subject to periodic excitations. The satellite structural design required a parametric study of structural configurations and consideration of the fabrication and assembly techniques, which resulted in a final structure which met all requirements at a structural mass fraction of 10%.

Reinert, R. P.↗
NASA NTRS1980

The Ascent Air Data System for the Space Shuttle

The Ascent Air Data System (AADS) consists of a biconic spike probe on the nose of the Space Shuttle External Tank. The final configuration of the AADS was selected on the basis of pressure measurement accuracy and simplification of the configuration. Wind tunnel calibrations were formulated to convert the 30 deg/10 deg spike measured pressures to the desired air data parameters for postflight analyses. Estimates of the system performance show that in general the user requirements for angle of attack and sideslip, and dynamic pressure are met or only slightly exceeded by the estimated errors.

Hillje, E. R.↗
NASA NTRS1980

Seasat-A satellite scatterometer instrument evaluation

The Seasat-A satellite scatterometer (SASS) was designed to measure ocean surface wind speed and direction in twenty-four independent cells over a 1000-km swath. It operated in the interrupted CW mode at a frequency of 14.6 GHz with four fan beam antennas and used Doppler filtering in the receiver for resolving the cells on the surface. The instrument began operating in space on July 6, 1978, and gathered normalized radar cross section data for approximately 2290 h. The purpose of this paper is to describe the in-orbit evaluation of the SASS hardware and its compatibility with the spacecraft. It has been determined that the scatterometer operated flawlessly throughout the mission, met all design requirements, and established a good data base for geophysical processing.

Johnson, J. W.↗
NASA NTRS1980

The Seasat-A synthetic aperture radar system

The paper discusses the Seasat-A synthetic aperture radar system (SAR). The objective of this system was to detect ocean waves from orbital altitudes. A SAR system operating at 1275 MHz was designed to meet this objective; the choice of wavelength resulted from the imagery obtained by aircraft during 1972 to 1974 and the ease of implementation. The Seasat-A SAR system was turned-on in orbit on July 4, 1978, and gathered imagery until the spacecraft bus failed in orbit in Oct. 1978. The hardware including the antenna, the radar sensor, and data-link subsystem, and the SAR data processing subsystem are described; the radar performance including the SAR system error budget and various SAR imageries are presented, concluding that the performance of the Seasat-A SAR system met all of its parameters on at least some of the imagery.

Jordan, R. L.↗
NASA NTRS1980

Three-dimensional structure of Escherichia coli initiator tRNA/f//Met/

The crystal structure of Escherichia coli tRNA(f)(Met), an initiator transfer RNA, has been determined. While grossly similar to that of the chain-elongating yeast tRNA(Phe), there are three major differences. One involves the folding of the anticodon loop; in particular, the position of the constant uridine, U33. This difference was unexpected and may be of functional significance.

Woo, N. H.↗
NASA NTRS1979

Space Telescope Digicon

The Digicon, chosen by NASA as the detector for the High Resolution Spectrograph (HRS) and the Faint Object Spectrograph (FOS) is a 512 parallel output channel vacuum photodetector. There are two HRS Digicons with spectral sensitivity ranges from 1050 A to 1800 A and 1150 A to 3000 A respectively, and two FOS Digicons, which have spectral ranges extending to 7000 A. The significant requirements for these devices are 0.01 counts per second background count rate per diode, state-of-the-art Digicon pulse height resolution (typical 15%) and a high degree of imaging precision and stability. The results of a manufacturing and test program to develop the Digicons coupled with extensive prior work has shown that these requirements can be met. The Digicon because of its inherent ruggedness is particularly well suited to space applications.

Alting-Mees, H. R.↗
NASA NTRS1979

Infrared focal plane arrays for planetary missions

Requirements for infrared detector array focal planes suitable for a set of prospective planetary missions are developed. Using the Galileo mission to Jupiter as a starting point, objectives and constraints applicable to outer planet missions are developed. The concept for an advanced mapping spectrometer utilizing 128 x 128 element infrared detector arrays is described. Specific implementations for the Saturn Orbiter Dual Probe mission, a Mars Orbiter mission, and a Titan Orbiter mission are defined. The analysis indicates that within the 1 to 5 micron range, broad scientific objectives for these missions can be met using focal plane arrays with detectivities on the order of 10 to the 14th cm sq root of Hz per W. The realization of such high detectivities in a low background application will necessitate careful development of the method by which the detector signals are multiplexed and read out.

Wellman, J. B.↗
NASA NTRS1980

The spectrum of IRC + 10216 from 2.0 to 8.5 microns

Low-resolution spectra of IRC + 10216 have been obtained from 2 to 8.5 microns from NASA's Kuiper Airborne Observatory at an altitude of 12.5 km (41,000 feet). Observations were made during 1976 January and 1977 February. In both sets of data, the spectral flux reaches its maximum between 6.0 and 6.6 microns and the previously reported 3.1-micron feature is observed; no obvious new absorption features have been found. The new data together with other spectral data and measurements of the spatial extent of IRC + 10216 impose conditions that must be met by models of the continuum. Several simple models for 2-8.5 micron radiation are examined. The new continuum data impose a constraint on the size of the grains in the cooler, optically thin part of the object. Earlier photometry has been combined with the present data to yield an improved value of the average period: 644 + or - 17 days. It appears that the variability is irregular and that the minima have been deeper in recent years than they were in 1965-1969.

Witteborn, F. C.↗