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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 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Materials processing in space

A brief overview of the current Materials Processing in Space Program is given, including a tentative schedule of flight experiments. Some recent results of processing materials (e.g., polymers and eutectic materials) in a microgravity environment are given, along with a discussion on additional proposed flight experiments. Ground-based results and the rationale for flight experimentation will be presented for other materials processes, including crystal growth.

W. A. Oran↗
NASA NTRS1983

Materials processing in space; Proceedings of the Special Conference, Cincinnati, OH, May 4, 5, 1982

An international review of materials processing in space is provided, taking into account the NASA materials processing in space program, European activities in the field of microgravity research, and Japanese material processing tests in space. The subjects considered are related to materials processing in a microgravity environment, industrial and university applications and involvement, and challenges and prospectives of microgravity research in space. Attention is given to a review of the containerless processing technologies and facilities, glass research in space, bubble behavior in molten glass in a temperature gradient, semiconductor crystal growth and segregation problems on earth and space, seeded crystal growth of pseudobinary systems with large liquidus-solidus separation, avenues and incentives for commercial use of a low-gravity environment, and the Universities Space Research Association and its role in the materials processing in space program.

Dunbar, B. J.↗
NASA NTRS1983

Glass research in space

Opportunities and problems associated with conducting containerless glass experiments in a microgravity environment are examined. Particular aspects of gel-derived glasses for space processing research are discussed, along with current space-related research activities in areas of amorphous phase separation, crystallization, and heterogeneous and homogeneous crystal nucleation.

Neilson, G. F.↗
NASA NTRS1992

Space Station Freedom - Initial plans for U.S. utilization

NASA's utilization plans for the Space Station Freedom (SSF) are outlined with references to the Consolidated Operations and Utilization Plan (COUP) being developed to cover the first five years of the program. The SSF is described with particular attention given to the spacecraft capabilities, and initial long-term U.S. objectives are set forth with more immediate corresponding research areas. U.S. plans include research in microgravity, life sciences, and technology, and payload concepts are shown to be in development for each area. The SSF is expected to be a useful resource for: (1) commercial research on crystal growth; (2) investigations into physical and chemical processes in the microgravitational environment; and (3) technology studies relevant to the efficient exploitation of space. The NASA Partner Utilization Plan on which these observations are based is being prepared for incorporation into the SSF COUP.

Epstein, Barry↗
NASA NTRS1996

Using naturally occurring polysaccharides to align molecules with nonlinear optical activity

The Biophysics and Advanced Materials Branch of the Microgravity Science and Applications Division at Marshall Space Flight Center has been investigating polymers with the potential for nonlinear optical (NLO) applications for a number of years. Some of the potential applications for NLO materials include optical communications, computing, and switching. To this point the branch's research has involved polydiacetylenes, phthalocyanins, and other synthetic polymers which have inherent NLO properties. The aim of the present research is to investigate the possibility of using naturally occurring polymers such as polysaccharides or proteins to trap and align small organic molecules with useful NLO properties. Ordering molecules with NLO properties enhances 3rd order nonlinear effects and is required for 2nd order nonlinear effects. Potential advantages of such a system are the flexibility to use different small molecules with varying chemical and optical properties, the stability and cost of the polymers, and the ability to form thin, optically transparent films. Since the quality of any polymer films depends on optimizing ordering and minimizing defects, this work is particularly well suited for microgravity experiments. Polysaccharide and protein polymers form microscopic crystallites which must align to form ordered arrays. The ordered association of crystallites is disrupted by gravity effects and NASA research on protein crystal growth has demonstrated that low gravity conditions can improve crystal quality.

Prasthofer, Thomas↗
NASA NTRS1987

Isothermal dendritic growth - A low gravity experiment

The Isothermal Dendritic Growth Experiment has been designed to test dendritic growth theory at low undercoolings, under microgravity conditions in the Space Shuttle Cargo Bay-borne Material Science Laboratory. The experiment will be essentially autonomous, although limited in-flight interaction through a computer interface is planned. A crystal growth chamber able to yield oriented single-crystal dendritic growth will be incorporated; 'seeding' the chamber with a crystal of the requisite orientation will not in itself meet this requirement.

Glicksman, M. E.↗
NASA NTRS1992

NASA's 'Mission to Planet Earth' begins with launch of UARS

The deployment of NASA's Upper Atmospher Research Satellite (UARS) is described in terms of the Shuttle flight and the expected contributions of the UARS to the 'Mission to Planet Earth'. The launch and daily activities of the Shuttle flight are described including microgravity-related materials experiments and the assembling of model space structures. The release of the UARS occurred without difficulty on the third day of the spaceflight, and experiments conducted included protein-crystal growth, middeck zero-gravity dynamics, rodent-physiology tests, cosmic radiation monitoring, and polymer-membrane processing. Millions of bytes of data resulted from the experiments conducted in space, and the UARS is expected to yield important data for the study of the global climate. The spaceflight culminated with the first nighttime landing at the Kennedy Space Center.

Schuiling, Roelof L.↗
NASA NTRS2003

Surface Tension and Viscosity of SCN and SCN-acetone Alloys at Melting Points and Higher Temperatures Using Surface Light Scattering Spectrometer

Succinonitrile has been and is being used extensively in NASA's Microgravity Materials Science and Fluid Physics programs and as well as in several ground-based and microgravity studies including the Isothermal Dendritic Growth Experiment (IDGE). Succinonitrile (SCN) is useful as a model for the study of metal solidification, although it is an organic material, it has a BCC crystal structure and solidifies dendriticly like a metal. It is also transparent and has a low melting point (58.08 C). Previous measurements of succinonitrile (SCN) and alloys of succinonitrile and acetone surface tensions are extremely limited. Using the Surface Light Scattering technique we have determined non invasively, the surface tension and viscosity of SCN and SCN-Acetone Alloys at different temperatures. This relatively new and unique technique has several advantages over the classical methods such as, it is non invasive, has good accuracy and measures the surface tension and viscosity simultaneously. The accuracy of interfacial energy values obtained from this technique is better than 2% and viscosity about 10 %. Succinonitrile and succinonitrile-acetone alloys are well-established model materials with several essential physical properties accurately known - except the liquid/vapor surface tension at different elevated temperatures. We will be presenting the experimentally determined liquid/vapor surface energy and liquid viscosity of succinonitrile and succinonitrile-acetone alloys in the temperature range from their melting point to around 100 C using this non-invasive technique. We will also discuss about the measurement technique and new developments of the Surface Light Scattering Spectrometer.

Tin, Padetha↗
NASA NTRS1995

Design and development of an all-solid-state laser unit for microgravity combustion applications

The laser-induced fluorescence (LIF) technique is a sensitive and noninvasive method for imaging of flames and for monitoring of temperature and the presence of transient molecular species in flames. Our research effort has two major objectives: (1) to use LIF to study the fundamentals of microgravity combustion via spectroscopic characterization of free radicals, and (2) to design and develop an all-solid-state portable laser unit for combustion studies in a microgravity environment. Well-characterized free radicals, namely hydroxyl (OH) and methoxy (CH3O), have analytically convenient bands that can be laser-excited in the 280-298 nm spectral region with the newly discovered solid-state tunable laser, which is based on the LiCaAIF6:Ce3+(LiCAF:Ce) single crystal pumped by the quadrupled (266 nm) output of a Q-switched YAG:Nd laser. The 266 nm YAG radiation (of about 10 mJ pulse energy) was split into two beams of about equal intensity, one used for photolysis of the free radical precursor and the other used for pumping the laser crystal. Tunability of the LiCAF:Ce laser was provided by a step-motor-driven Littrow-mounted diffraction grating. Laser excitation spectra of the CH3O radical was recorded in the 291.5-296.5 nm region with 0.15 cm(exp -1) resolution. Laboratory experiments have thus successfully shown that the idea of using the LiCAF:Ce laser as a dual-purpose photolysis and excitation source can pay rich dividends and that such a laser can be the center piece of an all-solid-state portable device that can be used for routine analytical investigations of microgravity combustion phenomena.

Kamal, Mohammed M.↗
NASA NTRS1999

Material Science Experiments on Mir

This paper describes the microgravity materials experiments carried out on the Shuttle/Mir program. There were six experiments, all of which investigated some aspect of diffusivity in liquid melts. The Liquid Metal Diffusion (LMD) experiment investigated the diffusivity of molten Indium samples at 185 C using a radioactive tracer, In-114m. By monitoring two different gamma ray energies (190 keV and 24 keV) emitted by the samples it was possible to measure independently the diffusion rates in the bulk and at the surface of the samples. The Queens University Experiment in Liquid Diffusion (QUELD) was the furnace facility used to process 213 samples for the five other experiments. These experiments investigated the diffusion, ripening, crystal growth, and glass formation in metal, semiconductor, and glass samples. This facility had the capability to process samples in an isothermal or gradient configuration for varying periods of time at temperatures up to 900 C. Both the LMD and the QUELD furnaces were mounted on the Microgravity Isolation Mount (MIM) which provided isolation from g-jitter. All the microgravity experiments were supported by the Space Acceleration Measurement System (SAMS); a three head three axes acceleration monitoring system which measured and recorded the acceleration environment.

Kroes, Roger L.↗
NASA NTRS1992

CONCAP 4: A Complex Autonomous Payload (CAP) for growing organic thin films in microgravity

A GAS facility has been developed for carrying out low temperature experiments. The arrangement being used on CONCAP IV-01 is designed for thin film growth in microgravity and can process up to twelve samples per mission. The nonlinear optical oven hardware can also be made suitable for other low temperature applications, such as gradient freeze and solution growth of crystals.

Carswell, W. E.↗
NASA NTRS1995

STS-94 Day 14 Highlights

On this fourteenth day of the STS-94 mission, the flight crew, Cmdr. James D. Halsell, Jr., Pilot Susan L. Still, Payload Cmdr, Janice E. Voss, Mission Specialists Michael L. Gernhardt and Donald A. Thomas, and Payload Specialists Gregory T. Linteris and Roger K. Crouch continue to focus on Columbia's Microgravity Science Laboratory mission. The seven astronauts work around the clock on two shifts supporting the more than 30 experiments in the Spacelab module. Work in the laboratory includes plant experiment and protein crystal growth status checks as well as work in the glovebox on the Coarsening in Solid-Liquid Mixtures experiment.

Source record↗
NASA NTRS1999

Measurement of Temperature Fluctuations and Microscopic Growth Rates in a Silicon Floating Zone Under Microgravity

USA Several microgravity experiments on sounding rockets and the Space Shuttle have shown that time-dependent thermocapillary (Marangoni) convection is the major cause for the formation of dopant striations in floating-zone grown semiconductor crystals, at least in small-scale systems not employing RF heating. To quantify this correlation, a silicon floating-zone experiment was performed during the TEXUS36 flight (February 7, 1998) in the monoellipsoid mirror furnace TEM02-ELLI. During the experiment, temperature fluctuations in the silicon melt zone and the microscopic growth rate were simultaneously measured. Temperature fluctuations of 0.5 C - 0.7 C with main frequencies between 0.1 Hz and 0.3 Hz were detectable. The microscopic growth rate fluctuated considerably around the average growth rate of 1 mm/min: rates from 4 mm/min to negative values (backmelting) were observed. Dopant striations are clearly visible in the Sb-doped crystal. They were characterized by Spreading Resistance measurements and Differential Interference Contrast microscopy. The frequencies associated with the dopant inhomogeneities correspond quite well with those of the temperature fluctuations and microscopic growth rates. 3D numerical simulations were performed to predict the optimum position of the temperature sensor, to evaluate characteristic temperature amplitudes and frequencies, and to give insight into the instability mechanisms of Marangoni convection in this configuration. The simulations were in good agreement with the experimental values, showing temperature fluctuations with frequencies ? 0.25 Hz and amplitudes up to 1.8 C at a position equivalent to that of the sensor tip in the experiment.

Croell, Arne↗
NASA NTRS2002

Detached Bridgman Growth of Germanium and Germanium-Silicon Alloy Crystals

Earth based experiments on the science of detached crystal growth are being conducted on germanium and germanium-silicon alloys (2 at% Si average composition) in preparation for a series of experiments aboard the International Space Station (ISS). The purpose of the microgravity experiments includes differentiating among proposed mechanisms contributing to detachment, and confirming or refining our understanding of the detachment mechanism. Because large contact angle are critical to detachment, sessile drop measurements were used to determine the contact angles as a function of temperature and composition for a large number of substrates made of potential ampoule materials. Growth experiments have used pyrolytic boron nitride (pBN) and fused silica ampoules with the majority of the detached results occurring predictably in the pBN. The contact angles were 173 deg (Ge) and 165 deg (GeSi) for pBN. For fused silica, the contact angle decreases from 150 deg to an equilibrium value of 117 deg (Ge) or from 129 deg to an equilibrium value of 100 deg (GeSi) over the duration of the experiment. The nature and extent of detachment is determined by using profilometry in conjunction with optical and electron microscopy. The stability of detachment has been analyzed, and an empirical model for the conditions necessary to achieve sufficient stability to maintain detached growth for extended periods has been developed. Results in this presentation will show that we have established the effects on detachment of ampoule material, pressure difference above and below the melt, and silicon concentration; samples that are nearly completely detached can be grown repeatedly in pBN.

Szofran, F. R.↗
NASA NTRS1986

Opportunity for academic research in a low-gravity environment - Crystal growth

The history of basic and applied research on crystal growth (CG), especially of semiconductor materials, is reviewed, stressing the dominance (at least in the U.S.) of industrial R&D projects over academic programs and the need for more extensive fundamental investigations. The NASA microgravity research program and the recommendations of the University Space Research Association are examined as they affect the availability of space facilities for academic CG research. Also included is a report on ground experiments on the effectiveness of magnetic fields in controlling vertical Bridgman CG and melt stability, using the apparatus employed in the Apollo-Soyuz experiments (Witt et al., 1978); the results are presented in graphs and briefly characterized. The role of NASA's microgravity CG program in stimulating academic work on CG, the importance of convection effects, CG work on materials other than semiconductors, and NSF support of CG research are discussed in a comment by R. F. Sekerka.

Matthiesen, D. H.↗
NASA NTRS1996

STS-75 Space Shuttle Mission Report

The STS-75 Space Shuttle Program Mission Report summarizes the Payload activities as well as the Orbiter, External Tank (ET), Solid Rocket Booster (SRB), Reusable Solid Rocket Motor (RSRM), and the Space Shuttle main engine (SSME) systems performance during the seventy-fifth flight of the Space Shuttle Program, the fiftieth flight since the return-to-flight, and the nineteenth flight of the Orbiter Columbia (OV-102). In addition to the Orbiter, the flight vehicle consisted of an ET that was designated ET-76; three SSME's that were designated as serial numbers 2029, 2034, and 2017 in positions 1, 2, and 3, respectively; and two SRB's that were designated BI-078. The RSRM's, designated RSRM-53, were installed in each SRB and the individual RSRMs were designated as 36OW53A for the left SRB, and 36OW053B for the right SRB. The primary objectives of this flight were to perform the operations necessary to fulfill the requirements of the Tethered Satellite System-1 R (TSS-1R), and the United States Microgravity Payload-3 (USMP-3). The secondary objectives were to complete the operations of the Orbital Acceleration Research Experiment (OARE), and to meet the requirements of the Middeck Glovebox (MGBX) facility and the Commercial Protein Crystal Growth (CPCG) experiment. Appendix A provides the definition of acronyms and abbreviations used thorughout the report. All times during the flight are given in Greenwich mean time (GMT) and mission elapsed time (MET).

Fricke, Robert W., Jr.↗
NASA NTRS2001

Growth of Solid Solution Single Crystals

The solidification of a solid solution semiconductor, having a wide separation between liquidus and solidus has been extensively studied in ground based, high magnetic field and Spacelab experiments. Two alloys of mercury cadmium telluride have been studied; with 80.0 mole percent of HgTe and 84.8 mole percent of HgTe respectively, the remainder being cadmium telluride. Such alloys are extremely difficult to grow by directional solidification on earth due to high solutal and thermal density differences that give rise to fluid flow and consequent loss of interface shape and composition. Diffusion controlled growth is therefore impossible to achieve in conventional directional solidification. The ground based experiments consisted of growing crystals in several different configurations of heat pipe furnaces, NASA's Advanced Automated Directional Solidification Furnace (AADSF), and a similar furnace incorporated in a superconducting magnet capable of operating at up to 5T. The first microgravity experiment took place during the flight of STS-62 in March 1994, with the AADSF installed on the second United States Microgravity Payload (USMP-2). The alloy was solidified at 3/4 inch per day over a 9 day period, and for the first time a detailed evaluation was performed correlating composition variations to measured residual acceleration. The second flight experiment took place in the fourth United States Microgravity Payload Mission (USMP-4) in November 1997. Due to contamination of the furnace system, analysis shows that the conditions prevailing during the experiment were quite different from the requirements requested prior to the mission. The results indicate that the sample did accomplish the desired objectives.

Lehoczky, Sandor L.↗
NASA NTRS1988

Preparation for microgravity - The role of the Microgravity Material Science Laboratory

Experiments at the NASA Lewis Research Center's Microgravity Material Science Laboratory using physical and mathematical models to delineate the effects of gravity on processes of scientific and commercial interest are discussed. Where possible, transparent model systems are used to visually track convection, settling, crystal growth, phase separation, agglomeration, vapor transport, diffusive flow, and polymer reactions. Materials studied include metals, alloys, salts, glasses, ceramics, and polymers. Specific technologies discussed include the General Purpose furnace used in the study of metals and crystal growth, the isothermal dendrite growth apparatus, the electromagnetic levitator/instrumented drop tube, the high temperature directional solidification furnace, the ceramics and polymer laboratories and the center's computing facilities.

Johnston, J. Christopher↗