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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Storing hydrogen in the form of light alloy hydrides

Different hydrides are investigated to find a system with a sufficiently high storage density (at least 3%). The formation of hydrides with light alloys is examined. Reaction kinetics for hydride formation were defined and applied to the systems Mg-Al-H, Mg-Al-Cu-H, Ti-Al-H, Ti-Al-Cu-H, and Ti-Al-Ni-H. Results indicate that the addition of Al destabilizes MgH2 and TiH2 hydrides while having only a limited effect on the storage density.

Freund, E.↗
NASA NTRS1982

Store separation from cavities at supersonic flight speeds

An experimental investigation has been conducted to determine the aerodynamic characteristics of a typical wing-control missile configuration during separation from a box-type cavity having depth to length ratios (D/L) ranging from 0.088 to 0.225. The cavity was located in a splitter plate that spanned the low Mach number test section of the Langley Unitary Plan Wind Tunnel. Aerodynamic characteristics are presented for Mach 2.36 and a free-stream unit Reynolds number of 2,000,000/ft. For the shallow cavity (D/L = 0.088), large interactions existed between the cavity and the flat plate flow field, which resulted in unfavorable separation characteristics for the missile model. For the deep cavity (D/L = 0.225), the flat plate flow field essentially bridged the cavity, resulting in minor interactions and favorable separation characteristics for the missile model.

Stallings, R. L., Jr.↗
NASA NTRS1984

Latch for Stored Cargo

Spherical latch elements distribute load over broad area. Concave and convex latching surfaces couple with one another to secure payload. Motor-drive pin locks latch in place; for active latch, second motor turns connecting plate attached to concave latch element. Spherical shape of latching elements distributes cargo weight over broad surface so no "hotspots" when cargo secured.

Clark, K. H.↗
NASA NTRS1983

The minimization of pylon-mounted store effects on air combat capability

Some effects of pylon-mounted missiles on aft-tail delta wing supersonic fighter concepts have been investigated. Whereas minimum drag penalties do occur with the addition of missiles, the effects at higher lifts, corresponding to maneuvering flight, are less severe and often favorable. Lower speeds and altitudes enhance the maneuvering capability and one-on-one air combat would probably tend to degenerate to subsonic speeds even though the combatants may be flying supersonic fighters. Higher speed (supersonic) flight might best be reserved for interceptors with long-range missiles where the weapon carriage effects at low angles of attack are of prime importance.

Spearman, M. L.↗
NASA NTRS1981

Remote sensing of stored precipitation, i.e., soil moisture and snow

The characteristics and performance of spaceborne precipitation radar systems are discussed. The development of a model is discussed. Examples of simulation results are given. It was found that the accuracy of rain rate estimates is improved by using higher resolution radar.

Schmugge, T. J.↗
NASA NTRS1983

Energy stores and switches for rail-launcher systems

An overview of existing switch and power supply technology applicable to space launch, a new candidate pulsed power supply for Earth-to-space rail launcher duty, the inverse railgun flux compressor, and a set of switching experiments to study further the feasibility of Earth-to-space launch are discussed.

Weldon, W. F.↗
NASA NTRS1982

Electron lithography STAR design guidelines. Part 3: The mosaic transistor array applied to custom microprocessors. Part 4: Stores logic arrays, SLAs implemented with clocked CMOS

The Mosaic Transistor Array is an extension of the STAR system developed by NASA which has dedicated field cells designed to be specifically used in semicustom microprocessor applications. The Sandia radiation hard bulk CMOS process is utilized in order to satisfy the requirements of space flights. A design philosophy is developed which utilizes the strengths and recognizes the weaknesses of the Sandia process. A style of circuitry is developed which incorporates the low power and high drive capability of CMOS. In addition the density achieved is better than that for classic CMOS, although not as good as for NMOS. The basic logic functions for a data path are designed with compatible interface to the STAR grid system. In this manner either random logic or PLA type structures can be utilized for the control logic.

Trotter, J. D.↗
NASA NTRS1986

Storing Chemicals in Packed Spheres

Reactants released by crushing or puncturing. Agglomerated gas-filled spheres hexagonally close packed and sintered or glued together into rods strung together at ends. Rods fed into crushing machine to release material in spheres as needed.

Wang, T. G.↗
NASA NTRS1985

Space Station nitrogen supply system based on stored chemicals

The Space Station atmosphere is to have an 'earth-like' composition, and nitrogen is to be routinely supplied to replace losses. The required nitrogen is to be provided by an innovative method, involving a catalytic dissociation of liquid N2H4 and separation of the product nitrogen and hydrogen mixture. The considered technique of nitrogen storage and resupply has several advantages in comparison to methods using either cryogenic liquid or high pressure nitrogen. One advantage is related to savings with respect to launch weight, while a second advantage is provided by the obtained hydrogen which is available for other uses within the Space Station.

Powell, F. T.↗
NASA NTRS1988

Stored mafic/ultramafic crust and early Archean mantle depletion

The global Nd isotopic evidence for early mantle depletion, which shows that some enriched reservoir must have persisted for at least 300 Ma in the early Archean, is discussed. Numerical models of the isotopic effects of melt extraction from the mantle are used to show that early oceanic crust is a more likely candidate for the enriched reservoir than early continental crust. It is suggested that subduction of an early mafic/ultramafic crust and temporary storage may be responsible for the depletion and high epsilon(Nd) values of the Archean upper mantle.

Chase, C. G.↗
NASA NTRS1990

Stored mafic/ultramafic crust and early Archean mantle depletion

Both early and late Archean rocks from greenstone belts and felsic gneiss complexes exhibit positive epsilon(Nd) values of +1 to +5 by 3.5 Ga, demonstrating that a depleted mantle reservoir existed very early. The amount of preserved pre-3.0 Ga continental crust cannot explain such high epsilon values in the depleted residue unless the volume of residual mantle was very small: a layer less than 70 km thick by 3.0 Ga. Repeated and exclusive sampling of such a thin layer, especially in forming the felsic gneiss complexes, is implausible. Extraction of enough continental crust to deplete the early mantle and its destructive recycling before 3.0 Ga ago requires another implausibility, that the sites of crustal generation of recycling were substantially distinct. In contrast, formation of mafic or ultramafic crust analogous to present-day oceanic crust was continuous from very early times. Recycled subducted oceanic lithosphere is a likely contributor to present-day hotspot magmas, and forms a reservoir at least comparable in volume to continental crust. Subduction of an early mafic/ultramafic oceanic crust and temporary storage rather than immediate mixing back into undifferentiated mantle may be responsible for the depletion and high epsilon(Nd) values of the Archean upper mantle.

Chase, Clement G.↗
NASA NTRS1992

Survival of epiphytic bacteria from seed stored on the Long Duration Exposure Facility (LDEF)

Microbial contamination in American spacecraft has previously been documented, however, potential risks to plants and humans in future space based controlled ecological life support systems (CELSS) have yet to be addressed directly. The current study was designed to determine the survival of microorganisms exposed to the relatively harsh conditions found in low Earth orbit (LEO). Total mean dosage for flight and ground control seeds were 210.2 and 0.9 rads, respectively. Bacteria were isolated by plating samples of seedwashings onto dilute tryptic soy agar. Pure isolates of morphologically distinct bacteria were obtained by standard microbiological procedures. Bacteria were grouped according to colony type and preliminary identification was completed using a fatty acid analysis system. Bacillus spp. were the primary microorganisms that survived on seed during the experiment. Results support the hypothesis that terrestrial microorganisms can survive long periods of time in relatively harsh LEO environments.

Schuerger, Andrew C.↗