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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Baseline Climate Variables for Earth System Modelling

The Baseline Climate Variables for Earth System Modelling (ESM-BCVs) are defined as a list of 135 variables which have high utility for the evaluation and exploitation of climate simulations. The list reflects the most frequently used elements of the Coupled Model Intercomparison Project Phase 6 (CMIP6) archive. Successive phases of CMIP have supported strong results in science and substantially influence international climate policy formulation. This paper responds to both interest in exploiting CMIP data standards in a broader range of climate modelling activities and a need to achieve greater clarity about the significance and intention of variables in the CMIP Data Request. As Earth system modelling archives grow in scale and complexity, there are emerging problems associated with weak standardisation at the variable collection level. That is, there are good standards covering how specific variables should be archived, but this paper fills a gap in the standardisation of which variables should be archived. The ESM-BCV list is intended as a resource for ESM intercomparison projects (MIPs) developing requests to enable greater consistency among MIPs and as a reference for modelling centres to enhance consistency within MIPs. Provisional planning for the CMIP7 Data Request exploits the ESM-BCVs as a core element. The baseline variable list includes 98 variables which have modest or minor data volume footprints and could be generated systematically when simulations are produced and archived for exploitation by the World Climate Research Programme (WCRP) community. A further 35 variables are classed as “high volume” and are only suitable for production when the resource implications are justified.

Juckes, Martin [University of Oxford (United Kingd↗
NASA NTRS1969

Pulse-code-modulation baseline correction for low signal-to-noise ratios

Time-shared integrate-hold-dump circuits separate the dc level due to the signal /bit information/ from the dc signal due to the baseline error. The system detects the baseline error, filters it, and then algebraically adds enough voltage to a servo loop to reduce the error to zero.

Stephens, T. J.↗
NASA NTRS1972

Single-stage evaluation of highly-loaded high-Mach-number compressor stages 5. Data and performance of baseline, corner-blow wall suction and combined corner blow wall suction stator

A single-stage compressor with a rotor tip speed of 1600 ft/sec and a 0.5 hub tip ratio was used to investigate the effects of several stator endwall treatment methods on stage range and performance. These endwall treatment methods consisted of stator corner-blow, annular wall suction upstream of stator leading edge, and combined corner-blow and annular wall suction. The overall stage performance with corner blow was essentially the same as the baseline performance. The performance for the annular wall suction and the combined corner-blow and wall suction showed a reduction in peak efficiency of 2.5 percentage points compared to the baseline data.

Nikkanen, J. P.↗
NASA NTRS1972

Very long baseline interferometry observations of radio emissions from geostationary satellites.

Review of the results of very long baseline interferometry (VLBI) observations of L-band emissions of the ATS-5 geostationary satellite, performed over a transcontinental baseline in 1970, as part of a more comprehensive program using radio stars as sources. Although the data were not sufficient to demonstrate fully the capability of the method for determining the orbital elements of a satellite and its inertial position, the analysis of the ATS observations show the presence of interference fringes related to the modulation waveform emitted by the satellite and to the various motions of the satellite. The measured VLBI time delays are in agreement with the geometry of the observations and with the instrumental delay, both determined independently.

Michelini, R. D.↗
NASA NTRS1973

Shuttle mission simulator baseline definition report, volume 1

A baseline definition of the space shuttle mission simulator is presented. The subjects discussed are: (1) physical arrangement of the complete simulator system in the appropriate facility, with a definition of the required facility modifications, (2) functional descriptions of all hardware units, including the operational features, data demands, and facility interfaces, (3) hardware features necessary to integrate the items into a baseline simulator system to include the rationale for selecting the chosen implementation, and (4) operating, maintenance, and configuration updating characteristics of the simulator hardware.

Burke, J. F.↗
NASA NTRS1975

Study of space shuttle orbiter system management computer function. Volume 1: Analysis, baseline design

A system analysis of the shuttle orbiter baseline system management (SM) computer function is performed. This analysis results in an alternative SM design which is also described. The alternative design exhibits several improvements over the baseline, some of which are increased crew usability, improved flexibility, and improved growth potential. The analysis consists of two parts: an application assessment and an implementation assessment. The former is concerned with the SM user needs and design functional aspects. The latter is concerned with design flexibility, reliability, growth potential, and technical risk. The system analysis is supported by several topical investigations. These include: treatment of false alarms, treatment of off-line items, significant interface parameters, and a design evaluation checklist. An in-depth formulation of techniques, concepts, and guidelines for design of automated performance verification is discussed.

Source record↗
NASA NTRS1975

Very long baseline interferometry using a communication satellite

A planned experiment is discussed in long-baseline interferometry, using the Communications Technology Satellite to transmit the base-band signal from one telescope to another for real-time correlation. A 20 megabit data rate is planned, calling for a delay-line of 10 MHz bandwidth and controllable delay up to 275 milliseconds. A number of sources will be studied on baselines from Ontario to West Virginia and California.

Swenson, G. W., Jr.↗
NASA NTRS1974

Transcontinental baselines and the rotation of the earth measured by radio interferometry

Nine separate very-long-baseline interferometry experiments, carried out in 1972 and 1973 with radio telescopes 3900 kilometers apart, yielded values for the baseline length with an rms deviation about the mean of less than 20 centimeters. The corresponding fractional spread is about five parts in 100,000,000. Changes in universal time and in polar motion were also determined accurately from these data. The rms scatter of these results with respect to those based on optical methods was 2.9 msec and 1.3 m, respectively. Solid-earth tides were apparently detected, but no useful estimate of their amplitude was extracted.

Shapiro, I. I.↗
NASA NTRS1975

Space Tug baseline description and status

The baseline definition of the Space Tug discussed herein is the one necessary to meet current payload mission model requirements in the mid-1980's for the least risk and development investment. This baseline Space Tug is a nominal 15-ft diameter, 30-ft long, LOX/LH2 stage with a main propellant capacity of about 50,000 lbs. Once deployed from the Space Shuttle in orbit, it is designed to automatically deliver spacecraft to a predetermined position and velocity and/or rendezvous and dock with prepositioned spacecraft for servicing or retrieval. The Tug would normally be returned to the vicinity of the Shuttle Orbiter, with or without spacecraft, to be retrieved and returned to earth in the Shuttle. Design characteristics, performance requirements, projected activities, and subsystems features are described.

Teir, W.↗
NASA NTRS1976

A very-long-baseline interferometer system for geodetic applications

A very-long-baseline interferometer system was designed and built for geodetic applications. Each interferometer terminal records a 360-kHz spectral band of noise from a compact extragalactic radio source. The center frequency of the spectral band can be selected to sample sequentially bands covering a much wider frequency range to obtain subnanosecond accuracy in group-delay measurements. A tunnel-diode pulse generator is used to calibrate the delays in the receiver. The necessary sets of algorithms and computer programs have been developed to analyze the data and have allowed the system to be employed to make accurate determinations of vector baselines, radio-source positions, polar motion, and universal time.

Whitney, A. R.↗
NASA NTRS1976

Ablative performance of uncoated silicone-modified and shuttle baseline reinforced carbon composites

The relative ablative performance of uncoated silicone-modified reinforced carbon composite (RCC) and uncoated shuttle baseline RCC substrates was investigated. The test specimens were 13 plies (5.3 to 5.8 millimeters) thick and had a 25-millimeter-diameter test face. Prior to arc tunnel testing, all specimens were subjected to a heat treatment simulating the RCC coating process. During arc tunnel testing, the specimens were exposed to cold wall heating rates of 178 to 529 kilowatts/sq m and stagnation pressures ranging from 0.015 to 0.046 atmosphere at Mach 4.6 in air, with and without preheating in nitrogen. The results show that the ablative performance of uncoated silicone-modified RCC substrates is significantly superior to that of uncoated shuttle baseline RCC substrates over the range of heating conditions used. These results indicate that the silicone-modified RCC substrate would yield a substantially greater safety margin in the event of complete coating loss on the shuttle orbiter.

Dicus, D. L.↗
NASA NTRS1976

Static and wind tunnel near-field/far field jet noise measurements from model scale single-flow baseline and suppressor nozzles. Volume 2: Forward speed effects

A model scale flight effects test was conducted in the 40 by 80 foot wind tunnel to investigate the effect of aircraft forward speed on single flow jet noise characteristics. The models tested included a 15.24 cm baseline round convergent nozzle, a 20-lobe and annular nozzle with and without lined ejector shroud, and a 57-tube nozzle with a lined ejector shroud. Nozzle operating conditions covered jet velocities from 412 to 640 m/s at a total temperature of 844 K. Wind tunnel speeds were varied from near zero to 91.5 m/s. Measurements were analyzed to (1) determine apparent jet noise source location including effects of ambient velocity; (2) verify a technique for extrapolating near field jet noise measurements into the far field; (3) determine flight effects in the near and far field for baseline and suppressor nozzles; and (4) establish the wind tunnel as a means of accurately defining flight effects for model nozzles and full scale engines.

Jaeck, C. L.↗
NASA NTRS1977

Extended performance solar electric propulsion thrust system study. Volume 2: Baseline thrust system

Several thrust system design concepts were evaluated and compared using the specifications of the most advanced 30- cm engineering model thruster as the technology base. Emphasis was placed on relatively high-power missions (60 to 100 kW) such as a Halley's comet rendezvous. The extensions in thruster performance required for the Halley's comet mission were defined and alternative thrust system concepts were designed in sufficient detail for comparing mass, efficiency, reliability, structure, and thermal characteristics. Confirmation testing and analysis of thruster and power-processing components were performed, and the feasibility of satisfying extended performance requirements was verified. A baseline design was selected from the alternatives considered, and the design analysis and documentation were refined. The baseline thrust system design features modular construction, conventional power processing, and a concentractor solar array concept and is designed to interface with the space shuttle.

Poeschel, R. L.↗
NASA NTRS1976

Solar central electric power generation - A baseline design

The paper presents the conceptual technical baseline design of a solar electric power plant using the central receiver concept, and derives credible cost estimates from the baseline design. The major components of the plant - heliostats, tower, receiver, tower piping, and thermal storage - are discussed in terms of technical and cost information. The assumed peak plant output is 215 MW(e), over 4000 daylight hours. The contribution of total capital investment to energy cost is estimated to be about 55 mills per kwh in mid-1974 dollars.

Powell, J. C.↗
NASA NTRS1978

The 25 kW power module - First step beyond the baseline STS

The backbone of the first reusable Space Transportation System (STS) is the Space Shuttle. The 25 kW Power Module is currently being defined by NASA as the first significant increment in capability beyond the baseline STS and is to be available for use in 1983. The Power Module is an orbit-based space system which will augment the capability of the Space Shuttle Orbiter to support Spacelab sortie missions and will provide a unique free-flying mode for a variety of payloads which require high capability, long duration, and man-tended operation. The Power Module will make it possible for the Space Shuttle Orbiter and Spacelab to remain on-orbit for periods of time significantly in excess of that provided by the baseline STS (7 days) without major penalty to the Shuttle and its payload.

Mordan, G. W.↗
NASA NTRS1978

Principles of very-long-baseline interferometry

The basic principles of very-long-baseline interferometry as related to its use in the determination of vector baselines, polar motion, and earth rotation are presented. Aspects relevant to geodetic applications that involve observations of extragalactic radio sources are covered. The instrumentation used in these observations and the basic observables and their simplest interpretation are described. Complications of the interpretation due to the various geophysical 'signals' and nongeophysical 'noise' that affect the observables are considered.

Shapiro, I. I.↗
NASA NTRS1979

Baseline automotive gas turbine engine development program

Tests results on a baseline engine are presented to document the automotive gas turbine state-of-the-art at the start of the program. The performance characteristics of the engine and of a vehicle powered by this engine are defined. Component improvement concepts in the baseline engine were evaluated on engine dynamometer tests in the complete vehicle on a chassis dynamometer and on road tests. The concepts included advanced combustors, ceramic regenerators, an integrated control system, low cost turbine material, a continuously variable transmission, power-turbine-driven accessories, power augmentation, and linerless insulation in the engine housing.

Wagner, C. E.↗
NASA NTRS1980

Error estimation for ORION baseline vector determination

Effects of error sources on Operational Radio Interferometry Observing Network (ORION) baseline vector determination are studied. Partial derivatives of delay observations with respect to each error source are formulated. Covariance analysis is performed to estimate the contribution of each error source to baseline vector error. System design parameters such as antenna sizes, system temperatures and provision for dual frequency operation are discussed.

Wu, S. C.↗