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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Low acceleration solid propellant rocket ignition study

A study was conducted to develop a solid-propellant rocket igniter system that would build up thrust at a controlled rate of less than 0.2 G/sec. The system consisted of a long burning, regressive burning, controlled flow igniter and an inhibited progressive burning surface in the main rocket motor. The igniter performed the dual role of igniting, under vacuum backpressure and low L* (motor free volume/nozzle throat area ratio) conditions, the nonrestricted portion of the propellant and providing the mass addition necessary to sustain combustion until the propellant burning area had increased sufficiently to provide a stable motor-chamber pressure. Two series of tests were conducted with existing small test motor hardware to: (1) demonstrate the feasibility of the concept, (2) determine the important parameters governing the system, and (3) obtain design guidelines for future scaled-up motor tests. A quasi-steady-state mass balance for the ignition system was written and programmed for use as a motor design tool.

Strand, L. D.↗
NASA NTRS1971

The measurement of radiation exposure of astronauts by radiochemical techniques

Gamma analyses of the neutron-activated fecal samples from the Apollo 12 and 13 missions were completed, and the data are being evaluated. Samples of the exposed Apollo 12 solar wind composition foil and blank foils were obtained for analysis of the Po-2/0 (Pb-210, Rn-222) content. It is expected that the determination of the Po-210 content of these foils will yield the concentration of radon atoms incident on the foil while exposed to the lunar atmosphere, and this indirectly will permit an estimate of the average uranium concentration of the lunar surface. Proposals to measure the cosmic-ray intensity and energy spectra inside and outside of late Apollo and Project Skylab spacecraft by exposing and subsequently analyzing pure metal foils, and to measure the elemental mass balance in Project Skylab astronauts by instrumental neutron activation analysis of the intake and excreta are summarized.

Brodzinski, R. L.↗
NASA NTRS1971

The measurement of radiation exposure of astronauts by radiochemical techniques

The urine specimens collected pre- and postflight from the Apollo 15 mission were analyzed for their radionuclide content. Cosmic radiation dose estimates of 695 and 660 mR are calculated from the observed Na-22 and Na-24 concentrations respectively. The concentrations of Na-22, Na-24, K-40, K-42, Cr-51, Fe-59, and Cs-137 are given. The potassium excretion patterns of high postflight and low preflight levels established for previous missions appears to be reversed for this mission. The concentrations of 23 major, minor, and trace elements in the fecal samples from the Apollo 14 astronauts are reported. Most elemental excretion rates are comparable to rates reported for earlier missions. The major exception is potassium where loss rates are the lowest ever observed. This coincides with the anomalously low excretion of potassium in postflight urine specimens. Apparent mass balance of calcium and iron continues as in the Apollo 12 and 13 missions.

Brodzinski, R. L.↗
NASA NTRS1972

Simulation of a flexible spinning vehicle

Results are presented of experimental investigation of the controlled and uncontrolled dynamical behavior of a rotating or artificial gravity space station including flexible body effects. A dynamically scaled model was supported by a spherical air bearing which provided a nearly moment free environment. Reaction jet system were provided for spin-up and spin-down and for damping of wobble motion. Two single-gimbal gyros were arranged as a control moment gyro wobble damping system. Remotely controllable movable masses were provided to simulate mass shift disturbances such as arise from crew motions. An active mass balance wobble damping system which acted to minimize the wobble motions induced by crew motions was also installed. Flexible body effects were provided by a pair of inertia augmentation booms. Inertia augmentation booms are contemplated for use on rotating space stations to cause the spin axis moment of inertia to be the largest of the three moments of inertia as is necessary to assure gyroscopic stability. Test runs were made with each of the control systems with the booms locked (rigid body) and unlocked (flexible body).

Baudry, W. A.↗
NASA NTRS1971

Continuous propagation of microalgae. III.

Data are presented which give the specific photosynthetic rate and the specific utilization rates of urea and carbon dioxide as functions of specific growth rate for Chlorella. A mathematical model expresses a set of mass balance relations between biotic and environmental materials. Criteria of validity are used to test this model. Predictive procedures are complemented by a particular model of microbial growth. Methods are demonstrated for predicting substrate utilization rates, production rates of extracellular metabolites, growth limiting conditions, and photosynthetic quotients from propagator variables.

Hanson, D. T.↗
NASA NTRS1972

Solid propellant grain design and internal ballistics

The ballistic aspects of grain design were studied to outline the steps necessary to achieve a successful grain design. The relationships of the grain design to steady-state mass balance and erosive burning are considered. Grain design criteria is reviewed, and recommended design criteria are included.

Source record↗
NASA NTRS1973

Snow cover surveys in Alaska from ERTS-1 data

September and October ERTS scenes have been analyzed to delineate snow cover patterns in northern Alaska's Brooks Range and on Mt. Wrangell, and active volcano in South Central Alaska. ERTS images demonstrate that the snow on the northern foothills of the Brooks Range are significantly more affected by katabatic wind action than are the southern foothills. Aufeis deposits along arctic rivers also can be identified in late summer. A survey of such aufeis deposits could identify additional summertime sources of fresh water supplies. Images of Mt. Wrangell permit monitoring of the interaction between volcanic heat and the mass balance of glaciers that exist on active volcanoes. Temporal changes in the areas of bare rock on the rim of the caldera on the summit reveal significant melting of new snow from an extensive storm on August 18. Digital analysis of data from subsequent passes over the summit on September 7, 23 and 24 revealed considerable bare rock exposed by melting, which is virtually impossible from solar heating at this altitude and date.

Benson, C. S.↗
NASA NTRS1973

Extravehicular mobility unit thermal simulator

The analytical methods, thermal model, and user's instructions for the SIM bay extravehicular mobility unit (EMU) routine are presented. This digital computer program was developed for detailed thermal performance predictions of the crewman performing a command module extravehicular activity during transearth coast. It accounts for conductive, convective, and radiative heat transfer as well as fluid flow and associated flow control components. The program is a derivative of the Apollo lunar surface EMU digital simulator. It has the operational flexibility to accept card or magnetic tape for both the input data and program logic. Output can be tabular and/or plotted and the mission simulation can be stopped and restarted at the discretion of the user. The program was developed for the NASA-JSC Univac 1108 computer system and several of the capabilities represent utilization of unique features of that system. Analytical methods used in the computer routine are based on finite difference approximations to differential heat and mass balance equations which account for temperature or time dependent thermo-physical properties.

Hixon, C. W.↗
NASA NTRS1973

Heat pipe stability. 1: A preliminary investigation into thermally assisted cavitation

The notion is introduced of thermally assisted cavitation by localized fluctuations in capillary forces. Because cavitation in liquids can be closely approximated by an isothermal process, only momentum and mass balances are used to introduce the notion for liquids under mechanical tension. Brief attention is given to developing a stability theory in terms of the stiffness and compliance coefficients for a working fluid. Interestingly, the particular thermodynamic approach taken can be used to suggest experiments relating working fluid performance to meniscus behavior. A correction to the liquid flow equation is suggested.

Source record↗
NASA NTRS1973

Constrained least-squares analysis of petrologic problems with an application to lunar sample 12040.

Many petrologic problems, which may be expressed as a set of linear equations, have been solved by least-squares analysis. In many cases insufficient attention has been paid to the physical conditions of the model resulting in incorrect application of the method. This paper presents a systematic treatment of the application of least-squares analysis to petrologic problems including the direct utilization of physical constraints and weighting factors in the problem, and the assessment of uncertainties in the solution. As an example, least-squares analysis is used to examine, in detail, the mass balance equations for lunar rock 12040 and to determine the consistency of the available analytical data.

Reid, M. J.↗
NASA NTRS1973

Cyclic oxidation evaluation - Approaching application conditions.

Review of 1000 to 1200 C cyclic oxidation testing conducted on potential aircraft gas turbine Ni-, Co-, and Fe-base alloys. Furnace and burner rig testing are discussed, and the results are compared for selected alloys. The alloys fall into two groups, depending on their Cr and Al contents. One group forms mainly Cr2O3/chromite spinel scale(s), while the other forms alpha Al2O3/aluminate spinel scale(s). Spalling on thermal cycling leading to increased metal consumption is associated with the appearance of a chromite spinel. In the case of high-velocity burner rig tests this chromite forming tendency is reinforced by Cr2O3 vaporization depleting Cr in the alloy. In both types of tests, specific weight change is used as an indirect indicator of metal attack, since direct metal loss measurements require destructive analysis. An alternative nondestructive metal loss estimating parameter, based on a tentative mass balance gravimetric approach, shows some potential.

Barrett, C. A.↗
NASA NTRS1973

Electrochemical carbon dioxide concentrator: Math model

A steady state computer simulation model of an Electrochemical Depolarized Carbon Dioxide Concentrator (EDC) has been developed. The mathematical model combines EDC heat and mass balance equations with empirical correlations derived from experimental data to describe EDC performance as a function of the operating parameters involved. The model is capable of accurately predicting performance over EDC operating ranges. Model simulation results agree with the experimental data obtained over the prediction range.

Marshall, R. D.↗
NASA NTRS1974

Exploratory tests of a simple aero-mechanical ride comfort system for lightly loaded aircraft

Some exploratory wind tunnel and radio-controlled free-flight tests were made with a small high-wing airplane model (1.23m wing span) to study the concept of a simple aero mechanical system intended to alleviate gust loads and improve ride comfort of lightly loaded aircraft. The system consisted essentially of the outer portions of each wing being hinged in the chordwise direction and connected directly to the wing flaps using internal counter weights to provide neutral mass balance. When the wing experienced a change in velocity or angle of attack, the movable wing panels, acting as sensors and flap actuators, deflected in response to the changes in lift on the wing. The corresponding movements of the interconnected flaps tended to reduce the changes in the wing lift.

Hewes, D. E.↗
NASA NTRS1974

Comparison of isothermal and cyclic oxidation behavior of twenty-five commercial sheet alloys at 1150 C

The cyclic and isothermal oxidation resistance of 25 high-temperature Ni-, Co-, and Fe-base sheet alloys after 100 hours in air at 1150 C was compared. The alloys were evaluated in terms of their oxidation, scaling, and vaporization rates and their tendency for scale spallation. These values were used to develop an oxidation rating parameter based on effective thickness change, as calculated from a mass balance. The calculated thicknesses generally agreed with the measured values, including grain boundary oxidation, to within a factor of 3. Oxidation behavior was related to composition, particularly Cr and Al content.

Barrett, C. A.↗
NASA NTRS1975

The atmosphere and ionosphere of Io

Models for Jupiter's innermost Galilean satellite's atmosphere, ionosphere, and sodium airglow are developed on the basis of recent observational data. The sodium emission detected by Brown (1973) is seen to require a collisional excitation process in Io's atmosphere, while the extended sodium emission measured by Trafton et al. (1974) may require scattering of the planetary radiation by an extended sodium cloud. The sodium is presumably present in bound form on Io's surface, and may be released by a sputtering mechanism proposed by Matson et al. (1974). The ionosphere detected by a radio occultation experiment on Pioneer 10 could be attributed to photoionization of atmospheric sodium, provided Io's atmosphere could sustain significant upward motions during daytime and downward motions during nighttime. The incomplete hydrogen torus observed by Judge and Carlson (1974) in the vicinity of Io appears to require a large supply of hydrogen from the satellite's atmosphere. Implications of the hydrogen torus for the energy and mass balance of Jupiter's magnetosphere are discussed.

Mcelroy, M. B.↗
NASA NTRS1976

COREST: A FORTRAN computer program to analyze paralinear oxidation behavior and its application to chromic oxide forming alloys

A FORTRAN computer program (COREST) was developed to analyze the high-temperature paralinear oxidation behavior of metals. It is based on a mass-balance approach and uses typical gravimetric input data. COREST was applied to predominantly Cr2O3-forming alloys tested isothermally for long times. These alloys behaved paralinearly above 1100 C as a result of simultaneous scale formation and scale vaporization. Output includes the pertinent formation and vaporization constants and kinetic values of interest. COREST also estimates specific sample weight and specific scale weight as a function of time. Most importantly, from a corrosion standpoint, it estimates specific metal loss.

Barrett, C. E.↗
NASA NTRS1977

Mineralogic and petrologic study of the low-temperature minerals in carbonaceous chondrites

Samples and petrographic thin sections of the Orgueil, Ivuna, and Alais chondrites were examined by optical, X-ray, and SEM techniques. Mineral species identified as primary vein constituents were epsomite, gypsum, and a calcium-magnesium carbonate. Relative abundances and textural relationships have suggested that fracture mineralization was a multi stage process, with individual mineralizations closely associated with impact brecciation events. Mass balance considerations of carbonaceous chondrite matrix support the prevailing view that the source of the fracture filling minerals was local. By inference they also suggest that the phyllosilicate matrix has been chemically altered and that there are probably very few primitive mineral phases in the primitive Cl chondrites.

Wood, J. A.↗
NASA NTRS1978

Space ecosynthesis: An approach to the design of closed ecosystems for use in space

The use of closed ecological systems for the regeneration of wastes, air, and water is discussed. It is concluded that such systems, if they are to be used for the support of humans in space, will require extensive mechanical and physico-chemical support. The reason for this is that the buffering capacity available in small systems is inadequate, and that natural biological and physical regulatory mechanisms rapidly become inoperative. It is proposed that mathematical models of the dynamics of a closed ecological system may provide the best means of studying the initial problems of ecosystem closure. A conceptual and mathematical model of a closed ecosystem is described which treats the biological components as a farm, calculates the rates of flow of elements through the system by mass-balance techniques and control theory postulates, and can evaluate the requirements for mechanical buffering activities. It is suggested that study of the closure of ecosystems can significantly aid in the establishment of general principles of ecological systems.

Macelroy, R. D.↗