SEARCH · Engineering Papers

Results for “Reentry”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,405 records · Page 78

All sources NASA NTRS DOE OSTI

NASA NTRS1980

STS-1 low-speed ground navigation console procedures

The space Transportation System 1 Flight onorbit mission phase is broken into three distinct subphases; those subphases being the rev 1 through rev 6 contigency reentry opportunities, the general onorbit time period, and the rev 34 to the postdeorbit Guam pass inclusive. The necessary information to ensure that sufficient data tables are accummulated in real time to support the postmission off line ancillary data analysis studies designed to support postmission ancillary data generation and investigation of mission related anomalies is given.

Jon Weaver↗

NASA NTRS1980

Space shuttle orbiter flow visualization study

The vortex flows generated at subsonic speed during the final portion of atmospheric reentry were defined using a 0.01 scale model of the orbiter in a diagnostic water tunnel. Flow visualization photographs were obtained over an angle-of-attack range to 40 deg and sideslip angles up to 10 deg. The vortex flow field development, vortex path, and vortex breakdown characteristics were determined as a function of angle-of-attack at zero sideslip. Vortex flows were found to develop on the highly swept glove, on the wing, and on the upper surface of the fuselage. No significant asymmetries were observed at zero sideslip in the water tunnel tests. The sensitivity of the upper surface vortex flow fields to variations in sideslip angle was also studied. The vortex formed on the glove remained very stable in position above the wing up through the 10 deg of sideslip tested. There was a change in the vortex lifts under sideslip due to effective change in leading-edge sweep angles. Asymmetric flow separation occurred on the upper surface of the fuselage at small sideslip angles. The influence of vortex flow fields in sideslip on the lateral/ directional characteristics of the orbiter is discussed.

Lorincz, D. J.↗

NASA NTRS1979

Proceedings of the 25th International Instrumentation Symposium, May 7-10, 1979, Anaheim, California

The papers deal essentially with the instrumentation needs of the transportation industry, machinery diagnostics, and energy research. The sessions covered include: acoustic emission, reentry vehicle ground and flight testing, performance of nose tip materials, instrumentation for solar heating and cooling systems, vibration measurement, data acquisition and analysis, system for aerospace pressure measurements, wind tunnel instrumentation and control, energy source instrumentation, nondestructive testing, pressure and flow measurements, automated test facilities, strain measurements, electrooptical instrumentation, thermal measurements, microcomputer applications in instrumentation and automation, flight testing, blast pressure measurement, two-phase liquid/gas mass flow measurement, and machinery monitoring and instrumentation.

Conferences↗

NASA NTRS1980

Supersonic flow over three-dimensional ablated nosetips using an unsteady implicit numerical procedure

The three-dimensional supersonic flow over passive, that is, nonablating, indented nosetips of reentry vehicles is determined using an unsteady implicit numerical algorithm which solves either the inviscid Euler equations or the 'thin-layer' Navier-Stokes equations. A nonorthogonal independent variable transformation is used to map the distorted physical domain, containing multiple zones of embedded subsonic flow and separated flow regions into a rectangular computational volume at whose boundaries the required permeable or impermeable boundary conditions are simulated. Use of the implicit algorithm results in faster convergence to the steady state because of a larger allowable time step over conventional explicit schemes. The numerical results obtained compare favorably with existing numerical solutions and experimental data for simple spheres which validates the program. Results are also presented for analytically defined indented bodies for both laminar and turbulent flow conditions that demonstrate the program's capability for computing such flows.

Kutler, P.↗

NASA NTRS1979

Development of high viscosity coatings for advanced Space Shuttle applications

Laboratory studies for increasing the thermal resistance of high viscosity coatings for silica reusable surface insulation are presented. The coatings are intended for the reentry temperature associated with advanced Space Shuttle applications which will involve aerodynamic shear forces during entry from earth orbits. Coating viscosity was increased by (1) reduction in the concentration of the low viscosity additive B2O3; (2) reduction in the particle size of the constituent powders in coatings; and (3) addition of a high viscosity glass former (GeO2). A coating system was produced by combining the three methods which showed apparent higher viscosity than the current coating, while satisfying all the current Shuttle Orbiter coating requirements.

Garofalini, S. H.↗

NASA NTRS1980

Collision avoidance in space

Collisions in earth orbital space between operational payloads and various forms of space debris (nonoperational payloads, nonfunctional mission-related objects and fragments resulting from collisions and explosions) are discussed and possible means of avoiding them are considered. From 10,000 to 15,000 objects are estimated to be in earth orbital space, most of which represent spacecraft fragments and debris too small to be detected and tracked by earth-based sensors, and it is considered likely that some of them will be or have already been involved in direct collisions with the ever increasing number of operational satellites and space stations. Means of protecting proposed large space structures and smaller spacecraft from significant damage by larger space objects, particularly in the 400-4000 km altitude range where most debris occurs, include structural redundancy and the double shielding of sensitive components. Other means of collision avoidance are the collection or relocation of satellites, rocket bodies and other objects by the Space Shuttle, the prevention of explosions and the disposal of spent rocket parts by reentry. Finally, a management structure would be required to administer guidelines for the prevention and elimination of space debris.

Kessler, D. J.↗

NASA NTRS1979

Description of the manufacturing challenges in producing the high-temperature reusable surface insulation for the thermal protection system of the Space Shuttle

The paper describes the high-temperature reusable surface insulation for the thermal protection system of the Space Shuttle. This system protects the Space Shuttle Orbiter on reentry and it is an externally attached, rigidized, fibrous silica, machined into 15 x 20 cm tiles. The tiles constitute the High-Temperature Reusable Surface Insulation (HRSI) system, and are used on over 70 percent of the exterior surface where peak temperatures range from 400 to 1260 C. Carbon-carbon leading edges are used in areas where peak temperatures exceed 1650 C, and a Nomex felt flexible insulation system is used in regions below 400 C. Approximately 32,000 tiles are used in the HRSI system, and due to vehicle configuration and aerodynamic requirements no two tiles are alike.

Forsberg, K.↗

NASA NTRS1980

Catalytic recombination of nitrogen and oxygen on high-temperature reusable surface insulation

The energy transfer catalytic recombination coefficient for nitrogen and oxygen recombination on the surface coating of high-temperature reusable surface insulation (HRSI) is inferred from stagnation point heat flux measurements in a high-temperature dissociated arc jet flow. The resulting catalytic recombination coefficients are correlated with an Arrhenius model for convenience, and these expressions may be used to account for catalytic recombination effects in predictions of the heat flux on the HRSI thermal protection system of the Space Shuttle Orbiter during reentry flight. Analysis of stagnation point pressure and total heat balance enthalpy measurements indicates that the arc heater reservoir conditions are not in chemical equilibrium. This is contrary to what is usually assumed for arc jet analysis and indicates the need for suitable diagnostics and analyses, especially when dealing with chemical reaction phenomena such as catalytic recombination heat transfer effects.

Scott, C. D.↗

NASA NTRS1980

Risks of nuclear waste disposal in space. III - Long-term orbital evolution of small particle distribution

A study of long term risks is presented that treats an additional pathway that could result in earth reentry, namely, small radioactive particles released in solar orbit due to payload fragmentation by accidental explosion or meteoroid impact. A characterization of such an event and of the initial mass size distribution of particles is given for two extremes of waste form strength. Attention is given to numerical results showing the mass-time distribution of material and the fraction of initial mass intercepted by earth. It is concluded that it appears that program planners need not be to concerned about the risks of this particular failure mechanism and return pathway.

Friedlander, A. L.↗

NASA NTRS1980

Equivalent-cone calculation of nitric oxide production rate during Space Shuttle re-entry

The amount of nitric oxide likely to be produced in the shock layer around a Space Shuttle orbiter vehicle during its reentry is calculated at one point on the trajectory. An equivalent-cone is defined as one that produces the same amount of nitric oxide as the orbiter. The amounts of nitric oxide produced by the cone are calculated at points along the trajectory to determine their total and altitudinal distribution. The results show that about 14 tonne nitric oxide is produced at each entry, the peak occurring at 68 km altitude.

Park, C.↗

NASA NTRS1982

Prolonging the Life of Refractory Fillers

Useful life of refractory glass-cloth gap filler is increased by coating it with a suspension of silicon carbide in butanol and polyethylene. Coating is applied to refractory-fiber cloth filler that seals gaps between insulating tiles on Space Shuttle orbiter. Tests showed that cloth fibers would be embrittled by extreme temperatures encountered on reentry into Earth's atmosphere and that only 25 percent of the thousands of fillers would be reusable after a mission. With coating, 85 percent of fillers would be reusable.

Schomburg, C.↗

NASA NTRS1982

Prolonging the Life of Refractory Fillers

Useful life of a refractory glass cloth gap filler is increased by coating it with a suspension of silicon carbide in butanol and polyethylene. Coating is applied to the refractory filler that seals gaps between insulating tiles on the Space Shuttle orbiter. Silicon carbide coating prevents embrittlement at high temperatures such as those encountered on reentry into Earth's atmosphere.

Schomburg, C.↗

NASA NTRS1980

Magsat attitude dynamics and control: Some observations and explanations

Before its reentry 7 months after launch, Magsat transmitted an abundance of valuable data for mapping the Earth's magnetic field. As an added benefit, a wealth of attitude data for study by spacecraft dynamicists was also collected. Because of its unique configuration, Magsat presented new control problems. With its aerodynamic trim boom, attitude control was given an added dimension. Minimization of attitude drift, which could be mapped in relative detail, became the goal. Momentum control, which was accomplished by pitching the spacecraft in order to balance aerodynamic and gravity gradient torques, was seldom difficult to achieve. Several interesting phenomena observed as part of this activity included occasional momentum wheel instability and a rough correlation between solar flux and the pitch angle required to maintain acceptable momentum. An overview is presented of the attitude behavior of Magsat and some of the control problems encountered. Plausible explanations for some of this behavior are offered. Some of the control philosophy used during the mission is examined and aerodynamic trimming operations are summarized.

Stengle, T. H.↗

NASA NTRS1980

A high performance multiplier processor for use with aerospace microcomputers

An MC68000 based microcomputer including a hardware multiplier processor has been designed and prototyped for a reentry vehicle navigation and control application. In this paper, the microcomputer is discussed with emphasis on the multiplier processor architecture, software control and theory of operation.

Pierce, P. E.↗

NASA NTRS1979

Producing the high temperature reusable surface insulation for the thermal protection system of the Space Shuttle

The primary insulation system used to protect the space shuttle orbiter on reentry is an externally attached, rigidized, fibrous silica which has been machined into tiles. The tiles constitute the temperature reusable surface insulation system and are used on over 70 percent of the vehicle exterior surface where peak temperatures range from 400 to 1260 C. Cargon-carbon leading edges are used in areas where peak temperatures exceed 1650 C and a felt flexible insulation is used in regions below 400 C. Approximately 32,000 tiles are used in the HRST system and because of vehicle configuration, aerodynamic requirements, and weight considerations no two tiles are alike. Fabrication and quality control procedures are described.

Forgsberg, K.↗

NASA NTRS1980

Skylab orbital lifetime prediction and decay analysis

A record (from preflight planning to earth impact) of skylab's orbital lifetime predictions, its actual decay and analysis are presented. Skylab provided a unique opportunity to develop, confirm and check out procedures and computer programs used for predicting lifetime and reentry. It provided verification of aerodynamic environment which was predicted for several aerodynamic configurations. It also provided data on the density model's reaction to rapidly changing solar flux over relatively short time periods. The effects of solar flux (and the uncertainty in the solar flux predictions) on orbital lifetime are discussed.

Dreher, P. E.↗

NASA NTRS1980

Environmental impacts of the satellite power system (SPS) on the middle atmosphere

The heavy lift launch vehicles (HLLV) proposed for use in constructing satellite power systems (SPS) would deposit various contaminants in the middle atmosphere, contaminants that would conceivable have adverse effects on climate and upper air structure. These contaminants consist of the major constitutents of water vapor, hydrogen, carbon dioxide, and carbon monoxide, and the minor constituents of sulfur dioxide and nitric oxide in the rocket effluent, as well as nitric oxide formed during reentry. To assess the magnitudes of the effects, new models or modified existing models were constructed.

Source record↗

NASA NTRS1980

A three-dimensional body-fitted coordinate system for flow field calculations on asymmetric nosetips

A three dimensional body-fitted coordinate system developed for use in the calculation of inviscid flows over ablated, asymmetric reentry vehicle nosetips is described. Because of the potential geometric asymmetries, no standard coordinate system (e.g., spherical, axisymmetric reference surface-normal) is capable of being closely aligned with the nosetip surface. To generate a 3-D, body-fitted coordinate system an analytic mapping procedure is applied that is conformal within each meridional plane of the nosetip; these transformations are then coupled circumferentially to yield a three dimensional coordinate system. The mappings used are defined in terms of hinge points, which are points selected to approximate the body contours in each meridional plane. The selection of appropriate hinge points was automated to facilitate the use of the resulting nosetip flow field code.

Hall, D. W.↗