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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

US plant and radiation dosimetry experiments flown on the Soviet satellite Cosmos 1129

Experiments included: 30 young male Wistar SPF rats used for wide range physiological studies; experiments with plants, fungi, insects, and mammalian tissue cultures; radiation physics experiments; a heat convection study; a rat embryology experiment in which an attempt was made to breed 2 male and 5 female rats during the flight; and fertile quail eggs used to determine the effects of spaceflight on avian embryogenesis. Specimens for US experiments were initially prepared at the recovery site or in Moscow and transferred to US laboratories for complete analyses. An overview of the mission focusing on preflight, on orbit, and postflight activities pertinent to the fourteen US experiments aboard Cosmos 1129 is presented.

Heinrich, M. R.↗
NASA NTRS1981

Cavity-backed, micro-strip dipole antenna array

A flush-mounted antenna assembly includes a generally rectangular, conductive, box structure open along one face to form a cavity. Within the cavity a pair of mutually orthogonal dielectric plane surfaces in an "egg crate" arrangement are mounted normal to the plane of the open face, each diagonally within the cavity. Each dielectric plane supports a pair of printed circuit dipoles typically each fed from the opposite side of the dielectric plane by a printed "cone-shaped" feed line trace which also serve as an impedance matching device and functions as a balun connected from an unbalanced strip line external feed. The open face of the conductive cavity can be flush mounted with a randome thereover, the assembly thereby being flush with the skin of a aircraft or space vehicle.

Ellis, H., Jr.↗
NASA NTRS1981

Use of LANDSAT for land use and habitat inventories for the New Jersey Pinelands

The New Jersey Heritage program surveyed available mapping information on landcover and vegetative communities and found that most commonly used sources, such as local land use maps and aerial photographs, were useful for individual sites, but either varied in their classifications or could not be used over extensive areas. A demonstration project using LANDSAT satellite information for the Great Egg Harbor/Tuckahoe watersheds was initiated with the goals of application (providing an inventory of vegetative communities and land use) flexibility (providing a method of collecting data which can be updated or modified in the future); and efficiency (allowing for an acceptable cost level by having staff undertake the project and avoid the more costly methods from air photo interpretation or on-site surveying. The classification procedure used is described and the spatial distributions of the 10 landcover classes determined are listed.

Tracy, C.↗
NASA NTRS1982

Honeycomb mirrors of borosilicate glass

The fabrication of different types of honeycomb mirrors with various kinds of borosilicate glass is discussed. Borosilicate glass is much less expensive to make than zero expansion glass, and can be used for ground-based applications. A mirror 60 cm in diameter made with a slotted strut or egg-crate honeycomb of 6 mm polished Pyrex plate is shown. The faceplates are 12 mm thick, laminated from the same 6 mm sheet. The result of an interferometric test is shown, with residual errors of about wavelength/8 RMS. An alternative fabrication technique for very large mirrors which require high quality bonds between separate sheets of thick Pyrex is described. The result of a recent test casting of a 60 cm honeycomb structure made in a mold with towers 14 cm square and 6 mm gaps between is shown, and methods to cast an entire mirror in one operation are discussed.

Angel, J. R. P.↗
NASA NTRS1983

Spacelab mission 4 - The first dedicated life sciences mission

Plans for the first Spacelab-4 mission dedicated entirely to the life sciences, are reviewed. The thrust of the scientific mission scheduled for late 1985 will be to study the acute effects of weightlessness on living systems, particularly humans. The payload of the Spacelab compartment will contain 24 experiments of which approximately half will involve humans. Among the major areas of interest are cardiovascular and pulmonary function, vestibular function, renal and endocrine physiology, hematology, nitrogen balance, immunological function, the gravitational biology of plants, inflight fertilization of frogs' eggs and the effects of zero gravity on monkeys and rats. In selecting the array of experiments an effort was made to combine investigations with complementary scientific objectives to develop animal models of human biological problems.

Perry, T. W.↗
NASA NTRS1985

Daylily as a System to Study Effects of Space Flight on Plant Development

The intent of the protoplast experimentation was to develop a system which would permit work with wall less counterparts of totipotent free cells as a model for a fertilized egg cell. It is clear that the daylily system is becoming a valuable tool with which to study any number of basic phases of higher plant development. The system can now be studied from a number of perspectives. A system amenable to rigorous experimentation was developed and can be used as a point of departure for studying problems of development in the space environment. This will be a prelude to the studying of the effect of hypogravity on higher plant development.

Krikorian, A. D.↗
NASA NTRS1985

Aquatic Invertebrate Development Working Group

Little definitive evidence exists to show that gravity plays a major role in embyrogenesis of aquatic invertebrates. Two reasons for this may be: (1) few studies have been done that emphasize the role of gravity; and (2) there simply may not be any gravity effect. The buoyant nature of the aquatic environment could have obscured any evolutionary effect of gravity. The small size of most eggs and their apparent lack of orientation suggests reduced gravitational influence. Therefore, it is recommended that the term development, as applied to aquatic invertebrates, be loosely defined to encompass behavioral and morphological parameters for which baseline data already exist.

Meyers, D.↗
NASA NTRS1986

Vection-induced gastric dysrhythmias and motion sickness

Gastric electrical and mechanical activity during vection-induced motion sickness was investigated. The contractile events of the antrum and gastric myoelectric activity in healthy subjects exposed to vection were measured simultaneously. Symptomatic and myoelectric responses of subjects with vagotomy and gastric resections during vection stimuli were determined. And laboratory based computer systems for analysis of the myoelectric signal were developed. Gastric myoelectric activity was recorded from cutaneous electrodes, i.e., electrogastrograms (EGGs), and antral contractions were measured with intraluminal pressure transducers. Vection was induced by a rotating drum. gastric electromechanical activity was recorded during three periods: 15 min baseline, 15 min drum rotation (vection), and 15 to 30 min recovery. Preliminary results showed that catecholamine responses in nauseated versus symptom-free subjects were divergent and pretreatment with metoclopramide HC1 (Reglan) prevented vection-induced nausea and reduced tachygastrias in two previously symptomatic subjects.

Koch, K. L.↗
NASA NTRS1985

Results from two recent ovserving system experiments

Two Observing System Experiments were carried out at (ECMWF). The European Center for Medium Range Weather Forecasting impact of various observing systems were examined for two periods during the EGGE year: November 8 to 9, 1979 (OSE-1) and February 22 to March 7, 1979 (OSE-II). Attempts were made to understand the effect of the observing systems on both the analyses and the quality of the short and medium range forecasts. The results confirm that the impact of a particular observing system (e.g., SATEM) is dependent on the level of synoptic activity present in the areas where this particular observing system is the main soruce of meteorological information. SATOB data are also shown to be improtant for the analyses of tropical regions, whereas SATEM data are of paramount importance for the extratropical analyses over ocean areas. Aircraft data, where available, are an invaluable addition to the global observational data base. These results therefore demonstrate clearly the value of each of the observing systems. The fact that, in particular circumstances, there may be some redundancy between the systems is a strength rather than a weakness of the composite global observing system.

Uppala, S.↗
NASA NTRS1986

US monkey and rat experiments flown on the Soviet Satellite Cosmos 1514

On December 14, 1983, the U.S.S.R. launched Cosmos 1514, an unmanned spacecraft carrying biological and radiation physics experiments from nine countries, including five from the United States. This was the fourth flight with U.S. experiments aboard one of the Soviet unmanned spacecraft. The Cosmos 1514 flight was limited to five days duration because it was the first nonhuman primate flight. Cosmos 1514 marked a significant departure from earlier flights both in terms of Soviet goals and the degree of cooperation between the U.S.S.R. and the United States. This flight included more than 60 experiments on fish, crawfish eggs, plants and seeds, 10 Wistar pregnant rats, and 2 young adult rhesus monkeys as human surrogates. United States specialist participated in postflight data transfer and specimen transfer, and conducted rat neonatal behavioral studies. An overview of the mission is presented focusing on preflight, on-orbit, and postflight activites pertinent to the five U.S. experiments aboard Cosmos.

Mains, R. C.↗
NASA NTRS1986

Geometric radiating surfaces for spacecraft thermal control

Various geometric radiating surface (GRS) configurations are evaluated analytically and experimentally for potential use in spacecraft thermal control systems. Egg-crate, honeycomb, flat-parallel, curved-parallel, chevron-shape, and composite fin radiator panel designs were evaluated in terms of mass, apparent emissivity, meteoroid protection, and ease of fabrication; the parallel-finned GRS in composite form was chosen as the most efficient design. The performance of the composite-finned GRS was compared with that of a silver-backed Teflon radiator. The emissivity and dissipative power capabilities of the GRS and radiator are measured. It is observed that the composite-finned GRS has 34 percent less surface area, 34 percent higher heat flux capability, greater meteoroid protection, and 2.8 times higher mass than the Teflon radiator. Future developments and applications for GRCs are discussed.

Keddy, M. D.↗
NASA NTRS1986

Protein crystal growth - Growth kinetics for tetragonal lysozyme crystals

Results are reported from theoretical and experimental studies of the growth rate of lysozyme as a function of diffusion in earth-gravity conditions. The investigations were carried out to form a comparison database for future studies of protein crystal growth in the microgravity environment of space. A diffusion-convection model is presented for predicting crystal growth rates in the presence of solutal concentration gradients. Techniques used to grow and monitor the growth of hen egg white lysozyme are detailed. The model calculations and experiment data are employed to discuss the effects of transport and interfacial kinetics in the growth of the crystals, which gradually diminished the free energy in the growth solution. Density gradient-driven convection, caused by presence of the gravity field, was a limiting factor in the growth rate.

Pusey, M. L.↗
NASA NTRS1986

Growth kinetics of tetragonal lysozyme crystals

A method for immobilizing protein crystals in small volumes to determine growth rates on various faces is applied to study the growth kinetics of the (100) face of tetragonal hen-egg white lysozyme crystals at different degrees of bulk saturation. In normal gravity, transport is found to be dominated by convection for crystal sizes larger than a few microns, while in a microgravity environment, transport is diffusion-limited for sizes up to a few mm. It is found that convection can be significant even in microgravity for crystals approaching cm sizes, and that lysozyme growth is limited by surface kinetics in normal gravity.

Pusey, M.↗
NASA NTRS1986

Spacelab 2 - Science in orbit

The success of Spacelab 2 is examined critically. Particular attention is given to the solar telescopes which were mounted on the instrument pointing system; these were designed to study solar irradiance, coronal helium, and exploding granules. Plasma experiments and the cosmic ray experiment (the 'Chicago Egg') are also described.

Page, T. L.↗
NASA NTRS1985

Continual LDEF program

The long-duration-exposure-facility (LDEF) experiment underway as of November 1985 is presented in drawings, diagrams, photographs, and tables and briefly characterized. The 57 LDEF experiments include studies of diffusion crystal growth; photovoltaic degradation of solar cells; thermal-coating performance; heat pipes; and cosmic-ray effects on seeds, spores, and eggs. Also included are answers to questions about LDEF retrieval posed at the conference.

Jones, James L.↗
NASA NTRS1986

Studies on precellular evolution - The encapsulation of polyribonucleotides by liposomes

Liposomes have been suggested as possible models of precellular systems formed in the early Archean earth from lipids of nonenzymatic origin. Since it is generally accepted that RNA molecules preceded double-stranded DNA molecules as genetic material, the encapsulation of polyribonucleotides within liposomes (made from dipalmitoyl phosphatidylcholine and from egg yolk phosphatidylcholine) was studied. Quantitative determinations show that approximately 50 percent of the available lipids form liposomes, and that up to 5 percent of the polyribonucleotides can be entrapped by them. Also studied was the encapsulation of polyribonucleotides in the presence of urea and cyanamide and of Zn(2+) and Pb(2+).

Baeza, I.↗
NASA NTRS1987

Liposomes with polyribonucleotides as model of precellular systems

Three types of liposomes were prepared under anoxic conditions: from dipalmitoyl phosphatidyl choline (DPPC), from egg yolk phosphatidyl choline (PC), and from PC with cholesterol (PC:Chol). These were used for encapsulation of poly(U) and poly(C). It was found that 36 to 70 percent of the available liposome lipids and 2 to 5 percent of the polyribonucleotides could be entrapped. An enhanced encapsulation of poly(U) and poly(C) by all three types of liposomes was observed in the presence of 0.001 to 0.01 M Zn(2+), with the effect being greatest with DPPC. The presence of 1.0 M urea inhibited the formation of PC liposomes.

Baeza, Isabel↗