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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 1,297 records · Page 72
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

The FX/90: A proposal in response to a low Reynolds Number station keeping mission

The FX/90 is a remotely piloted vehicle designed to fly at Reynolds numbers below 2 x 10 to the 5th power. Several applications exist for this type of flight, such as low altitude flight of very small aircraft. The design presented here allows investigation into the unique problems involved in low Reynolds number flight, which will, in turn, further understanding of this flight regime. The aircraft will operate in a steady flight environment, free from significant atmospheric turbulence and weather effects. The F-90 has a 39 in. fuselage which is constructed of balsa and plywood. The landing gear for the aircraft is a detachable carriage on which the aircraft rests. The aerodynamic planform is a rectangular wing (no taper or sweep) with a chord of 9 in., a wingspan of 72 in., and is constructed entirely out of styrofoam. The propulsion system is a puller configuration mounted on the front of the fuselage. It consists of an Astro 05 engine and a 10-6 two bladed propeller. Control of the aircraft is accomplished through the use of two movable control surfaces: elevators for pitch control, and a rudder for yaw control. The aircraft is soundly constructed, highly maneuverable, and adequately powered. Furthermore, the investigation into alternative technologies, most notably the styrofoam wing and the detachable landing gear, holds promise to improve the performance of the aircraft.

Wirthman, David↗
NASA NTRS1990

Design of a device to remove lunar dust from space suits for the proposed lunar base

The National Aeronautics and Space Administration plans to begin construction of a lunar base soon after the turn of the century. During the Apollo missions, lunar dust proved to be a problem because the dust adhered to all exposed material surfaces. Since lunar dust will be a problem during the establishment and operation of this base, the need exists for a device to remove the dust from space suits before the astronauts enter clean environments. The physical properties of lunar dust were characterized and energy methods for removing the dust were identified. Eight alternate designs were developed to remove the dust. The final design uses a brush and gas jet to remove the dust. The brush bristles are made from Kevlar fibers and the gas jet uses pressurized carbon dioxide from a portable tank. A throttling valve allows variable gas flow. Also, the tank is insulated with Kapton and electrically heated to prevent condensation of the carbon dioxide when the tank is exposed to the cold (- 240 F) lunar night.

Harrington, David↗
NASA NTRS1990

A proposal to demonstrate production of salad crops in the space station mockup facility with particular attention to space, energy, and labor constraints

A desire for fresh vegetables for consumption during long term space missions has been foreseen. To meet this need in a microgravity environment within the limited space and energy available on Space Station requires highly productive vegetable cultivars of short stature to optimize vegetable production per volume available. Special water and nutrient delivery systems must also be utilized. As a first step towards fresh vegetable production in the microgravity of Space Station, several soil-less capillary action media were evaluated for the ability to support growth of two root crops (radish and carrot) which are under consideration for inclusion in a semi-automated system for production of salad vegetables in a microgravity environment (Salad Machine). In addition, productivity of different cultivars of radish was evaluated as well as the effect of planting density and cultivar on carrot production and size. Red Prince radish was more productive than Cherry Belle and grew best on Jiffy Mix Plus. During greenhouse studies, vermiculite and rock wool supported radish growth to a lesser degree than Jiffy Mix Plus but more than Cellular Rooting Sponge. Comparison of three carrot cultivars (Planet, Short n Sweet, and Goldinhart) and three planting densities revealed that Short n Sweet planted at 25.6 sq cm/plant had the greatest root fresh weight per pot, the shortest mean top length, and intermediate values of root length and top fresh weight per pot. Red Prince radish and Short n Sweet carrot showed potential as productive cultivars for use in a Salad Machine. Results of experiments with solid capillary action media were disappointing. Further research must be done to identify a solid style capillary action media which can productively support growth of root crops such as carrot and radish.

Brooks, Carolyn A.↗
NASA NTRS1990

The Screem-J4D: A proposal in response to a low Reynolds number station keeping mission

The Screem-J4D is a remotely piloted airplane that was designed to fly at a chord Reynold's number of 100,000 while performing figure-8 maneuvers in a restricted area. It has a high aspect ratio main wing with a conventional empennage giving it a sailplane appearance. A specifications table and three-view drawing is provided. The flight plan calls for ascent to cruise altitude at 20 ft and then perform three figure-8 turns around pylons. These pylons will be separated by fifty yards and stationed inside a sports facility. Once completed, the pilot is to make use of any remaining power by loitering before landing the plane. The propulsion system of the J4D consists of a propeller-electric motor combination with the prop mounted at the front of the fuselage. In order to provide sufficient lift for low speed travel, the J4D has an aspect ratio of 11.72 with an 8.2 inch mean chord. The wing consists of a spar and rib construction with Micafilm skin. A combination of directional and longitudinal control will enable the J4D to perform the figure-8 maneuvers. However, in order to avoid the construction and servo weight of ailerons, the rudder was designed to be over one-half the size of the vertical tail to insure that the proper roll motion could be attained.

Source record↗
NASA NTRS1990

An automated calibration laboratory for flight research instrumentation: Requirements and a proposed design approach

NASA's Dryden Flight Research Facility (Ames-Dryden), operates a diverse fleet of research aircraft which are heavily instrumented to provide both real time data for in-flight monitoring and recorded data for postflight analysis. Ames-Dryden's existing automated calibration (AUTOCAL) laboratory is a computerized facility which tests aircraft sensors to certify accuracy for anticipated harsh flight environments. Recently, a major AUTOCAL lab upgrade was initiated; the goal of this modernization is to enhance productivity and improve configuration management for both software and test data. The new system will have multiple testing stations employing distributed processing linked by a local area network to a centralized database. The baseline requirements for the new AUTOCAL lab and the design approach being taken for its mechanization are described.

Oneill-Rood, Nora↗
NASA NTRS1987

Simulation of real-gas effects on pressure distributions for a proposed Aeroassist Flight Experiment vehicle and comparison to prediction

Pressure distributions measured on a 60-deg elliptic cone, raked off at a 73-deg angle and having an ellipsoid nose (ellipticity equal to 2.0), are presented for a range of angle of attack from -10 to 15 deg. The high normal shock density ratio aspect of a real gas was simulated by testing in Mach-6 air (normal shock density ratio equal to 5.25) and Mach 6 CF4 (normal shock density ratio equal to 12.0). The effects of Reynolds number, angle of attack, and normal shock density ratio on these measurements are examined, and comparisons are made to an inviscid flowfield computer code known as HALIS. A significant effect of density ratio on pressure distributions on the cone section of the configuration was observed; the magnitude of this effect decreased with increased angle of attack. The effect of Reynolds number on pressures was negligible for forebody pressure distributions, but a measurable effect was noted on base pressures. In general, the HALIS code accurately predicted the measured pressure distributions in air and CF4.

Micol, John R.↗
NASA NTRS1989

Implications of AAOE observations for proposed chemical explanations of the seasonal and interannual behavior of Antarctic ozone

Model simulations were used to investigate the seasonal and interannual behavior of ozone for different choices of initial odd nitrogen concentration in July and different assumptions on the heterogeneous reactions, with particular consideration given to the possible contribution of chlorine chemistry to the ozone hole phenomenon. The numerical experiments were selected based on the simulations of the observed trace gas concentrations during the Airborne Antarctic Ozone Experiment in 1987. In all cases considered, the catalytic cycle associated with the formation and photolysis of Cl2O2 could account for more than half of the photochemical removal of O3 within the Antarctic vortex through mid-September. The reaction of BrO with ClO, which accounts for 15-20 percent of O3 removal in the same period, tends to play a more important role toward the end of September, when the concentration of ClO is expected to decrease. No simple relationship was found between the increase in chlorine lavel and the interannual decrease in Antarctic O3.

Ko, M. K. W.↗
NASA NTRS1989

Preliminary design for a proposed Saturn mission with a second Galileo spacecraft

A study has been performed to assess the feasibility of using a second Galileo spacecraft for a Titan-probe/Saturn-orbiter mission that would be launched on a Shuttle/Centaur in the early 1990s. The interplanetary transfer is accomplished by means of a Delta-V earth-gravity-assist trajectory with a 3-year flight time from launch to earth flyby. Just prior to arrival at Saturn, the Titan probe is released, and the orbiter is used to relay data from the probe back to earth as it performs a close gravity-assist flyby of Titan. The orbiter then conducts a satellite tour containing multiple encounters with Saturn's satellites. Discussed in detail are the optimal trajectory design, Saturn approach trajectory design (Titan flyby, probe relay, and initial orbit selection), satellite tour design, and mission performance.

D'Amario, Louis A.↗
NASA NTRS1990

A redshift survey toward a proposed void of galaxies suggested by the distribution of Abell clusters

A program of redshift measurements was carried out in a region of the sky in which a relative under-density of Abell clusters had been used to infer the presence of a large (diameter about 40/h Mpc) void in the general galaxy distribution. The purpose of this study was to investigate whether the large-scale distribution of galaxies is traced by the distribution of rich clusters. Redshifts are presented for 308 galaxies in the Zwicky Catalog in a 234 square degree region centered on R.A. about 2h, Decl. about 12 deg of which 229 have been newly measured. These data reveal a pattern of filamentary structure alternating with voids of characteristic diameter about 25-30/h Mpc, throughout the volume sampled. While the redshift data reveal an underdensity in the distribution of galaxies in the general region suggested by the Abell cluster distribution, they do not support the existence there of a 40/h Mpc diameter void.

Willick, Jeffrey A.↗
NASA NTRS1990

Aerothermodynamic measurements on a proposed assured crew return vehicle (ACRV) lifting-body configuration at Mach 6 and 10 in air

A 0.02-scale model of a lifting-body concept for possible application to the Assured Crew Return Vehicle from Space Station Freedom was tested at Mach 6 and 10 in air. Thermal mappings and surface streamline patterns were obtained at angles of attack ranging from 0 to 30 deg and unit Reynolds numbers Re from 2 to 8 x 10 to the 6th/ft. Areas that experienced the highest heating were near the model nose and tip-fin leading edges. The effect of Re on windward centerline heating coefficients was negligible, whereas increases in angles of attack produced increases in heating. At Mach 6 and the highest unit Re, turbulent heat at the windward centerline was three to four times the laminar level. Leeward crossflow separation and vortex reattachment along the centerline are evident across the Re and angle-of-attack ranges tested, indicative of a complex flowfield.

Horvath, Thomas J.↗
NASA NTRS1990

A proposed Kalman filter algorithm for estimation of unmeasured output variables for an F100 turbofan engine

To develop advanced control systems for optimizing aircraft engine performance, unmeasurable output variables must be estimated. The estimation has to be done in an uncertain environment and be adaptable to varying degrees of modeling errors and other variations in engine behavior over its operational life cycle. This paper presents an approach to estimate unmeasured output variables by explicitly modeling the effects of off-nominal engine behavior as biases on the measurable output variables. A state variable model accommodating off-nominal behavior is developed for the engine, and Kalman filter concepts are used to estimate the required variables. Results are presented from nonlinear engine simulation studies as well as the application of the estimation algorithm on actual flight data. The formulation presented has a wide range of application since it is not restricted or tailored to the particular application described in the paper.

Alag, Gurbux S.↗
NASA NTRS1990

A proposed definition for a pitch attitude target for the microburst escape maneuver

The Windshear Training Aid promulgated by the Federal Aviation Administration (FAA) defines the practical recovery maneuver following a microburst encounter as application of maximum thrust accompanied by rotation to an aircraft-specific target pitch attitude. In search of a simple method of determining this target, appropriate to a variety of aircraft types, a computer simulation was used to explore the suitability of a pitch target equal in numerical value to that of the angle of attack associated with stall warning. For the configurations and critical microburst shears simulated, this pitch target was demonstrated to be close to optimum.

Bray, Richard S.↗
NASA NTRS1990

An ADP proposal to study the formation and evolution of dust-embedded clusters

Using high resolution and high sensitivity IRAS data at 12 and 25 microns low mass stars were studied which have recently formed in the Ophiuchus, Corona Australis, and IC1396 dark clouds. The successful application of these techniques to the Rho Ophiuchi infrared cluster is briefly described. The status of research performed is also presented.

Wilking, Bruce A.↗
NASA NTRS1991

New space research frequency band proposals in the 20- to 40.5-GHz range

Future space research communications systems may require spectra above 20 GHz. Frequency bands above 20 GHz are identified that are suitable for space research. The selection of the proper bands depends on consideration of interference with other radio services, adequate bandwidths, link performance, and technical requirements for practical implementation.

Bishop, D. F.↗
NASA NTRS1990

A proposed Kalman filter algorithm for estimation of unmeasured output variables for an F100 turbofan engine

To develop advanced control systems for optimizing aircraft engine performance, unmeasurable output variables must be estimated. The estimation has to be done in an uncertain environment and be adaptable to varying degrees of modeling errors and other variations in engine behavior over its operational life cycle. This paper represented an approach to estimate unmeasured output variables by explicitly modeling the effects of off-nominal engine behavior as biases on the measurable output variables. A state variable model accommodating off-nominal behavior is developed for the engine, and Kalman filter concepts are used to estimate the required variables. Results are presented from nonlinear engine simulation studies as well as the application of the estimation algorithm on actual flight data. The formulation presented has a wide range of application since it is not restricted or tailored to the particular application described.

Alag, Gurbux S.↗
NASA NTRS1991

Flight test to determine feasibility of a proposed airborne wake vortex detection concept

This investigation was conducted to determine the radial extent at which aircraft mounted flow vanes or roll rate gyros can sense the circulatory flow field that exists around the lift induced vortex system generated by an aircraft in flight. The probe aircraft was equipped with wingtip sensors for measuring angle of attack and angle of sideslip, and with a fuselage mounted gyroscope for measuring roll rate. Analysis of flight test data indicated that the vortex was detectable at a lateral distance of about 105 feet (best results) using unsophisticated equipment. Measurements were made from the centerline of the probe aircraft to the center of the nearest vortex with the probe aircraft flying between one half and one and one half miles behind the vortex generating aircraft.

Branstetter, James R.↗
NASA NTRS1990

Evaluation of Proposed Rocket Engines for Earth-to-Orbit Vehicles

The objective is to evaluate recently analyzed rocket engines for advanced Earth-to-orbit vehicles. The engines evaluated are full-flow staged combustion engines and split expander engines, both at mixture ratios at 6 and above with oxygen and hydrogen propellants. The vehicles considered are single-stage and two-stage fully reusable vehicles and the Space Shuttle with liquid rocket boosters. The results indicate that the split expander engine at a mixture ratio of about 7 is competitive with the full-flow staged combustion engine for all three vehicle concepts. A key factor in this result is the capability to increase the chamber pressure for the split expander as the mixture ratio is increased from 6 to 7.

Martin, James A.↗
NASA NTRS1991

Using HST: From proposal to science

The following subject areas are covered: a short history; uses of network STSCII (general communication, science collaboration, functional activities, internal data management, and external data access); proposal/observation handling; DMF access; and future uses and requirements.

Shames, P.↗