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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Possible steps in the evolutionary development of bird navigation

Hypotheses are presented to explain the evolutionary development of navigational ability in migratory birds. Areas of discussion to describe the possible techniques are: (1) sun compass, (2) bicoordinate navigation, (3) star compass, (4) wind cues, (5) earth magnetic field, and (6) landscape features. It is concluded that landscape is the single most important cue for orientation of nonmigratory birds. The long range migratory birds appear to use a combination of cues with the relative importance of the cue dependent upon the species of the bird involved.

Bellrose, F. C.↗
NASA NTRS1971

Evolutionary models of nucleosynthesis in the galaxy.

A model of the galaxy is constructed and evolved in which the integrated influence of stellar and supernova nucleosynthesis on the composition of the interstellar gas is traced numerically. Our detailed assumptions concerning the character of the matter released from evolving stars and supernovae are guided by the results of recent stellar evolutionary calculations and hydrodynamic studies of supernova events. It is difficult to visualize an epoch of massive star formation in the collapsing gas cloud which formed our galaxy which would enrich the gas rapidly enough to account for the level of heavy element abundances in halo population stars; we have therefore proposed a stage of star formation which is entirely pregalactic in character. We suggest that the Jeans' length-sized initial condensations in the expanding universe discussed by Peebles and Dicke may provide the appropriate setting for this first generation of stars. Guided by these considerations, and by the need for a substantial quantity of 'unseen' mass to bind our local group of galaxies, we have constructed a model of the galaxy in which this violent early phase of massive star formation produces both (1) approximately 25% of the level of heavy elements observed in the solar system and (2) an enormous unseen mass in the form of black holes.

Truran, J. W.↗
NASA NTRS1971

Study of an evolutionary interim earth orbit program

An evolutionary, gradual, and step-wise spacecraft systems technology development from those used on the Apollos and Skylab 1 to that required for the space station was considered. The four mission spacecraft were dry workshop versions of the Saturn 4-B stage, and each individually configured, outfitted and launched by INT-21 vehicles. These spacecraft were evaluated for crews of three, six and nine men and for mission lifetimes of one year. Two versions of the Apollo CSM, a three man and a four man crew, were considered as the logistic vehicle. The solar cell electrical power system of the first mission evolves into a light weight panel system supplemented by an operating isotope-Brayton system on the later missions. The open life support system of the first mission evolves to a system which recovers both water and oxygen on the last mission. The data handling, communications, radiation shielding, micrometeoroid protection, and orbit keeping systems were determined. The program costs were estimated and, excluding operational costs, the cost for each mission would average about $2 billion of which one-sixth would be for development, one-fourth for experiments, and the balance for vehicle acquisition.

Anderson, J. L.↗
NASA NTRS1972

An evolutionary calculation of Jupiter.

A preliminary evolutionary calculation has been made for a stellar object of 0.001 solar mass composed of pure hydrogen. The star undergoes the gravitational contraction from an initial radius of 35 times the present radius of Jupiter (Rj). We assume the interior to be in convective equilibrium throughout the evolution. The evolution has been followed for 1 b.y. at which time R = 2.8 Rj and the central temperature is 18,000 K.

Grossman, A. S.↗
NASA NTRS1972

An evolutionary calculation of Jupiter

A preliminary evolutionary calculation was made for a stellar object of 0.001 solar mass composed of pure hydrogen. The star undergoes the gravitational contraction from an initial radius of 35 times the present radius of Jupiter (R sub Jup). The interior is assumed to be in convective equilibrium throughout the evolution. The evolution has been followed for 10 to the ninth power y at which time R = 2.8 R sub Jup and the central temperature is 18000 K. The log of the luminosity (in units of solar luminosity) and effective temperature due to the internal energy sources are log L/solar luminosity = -9.0 and log T sub e = 1.77.

Grossman, A. S.↗
NASA NTRS1975

Infrared galaxies - Evolutionary stages of massive star formation

We cite evidence which indicates that infrared galaxies may represent evolutionary stages during which a large number of massive stars are being formed. The lifetimes of these stars would be rather short (1-10 million years), and the resulting supernova explosions could account for the level of nonthermal activity which often accompanies the thermal infrared emission.

Harwit, M.↗
NASA NTRS1977

Crater evolutionary tracks

The technique proposed in the present paper for studying planetary surface processes is based on the measurement of crater rim height, h, depth, d, and diameter, D. The h/d and d/D ratios provide a quantitative description of crater morphology as well as a quantitative method for assessing the relative importance of competing crater modification processes (since h, d, and D change as a crater is degraded by surface processes, and h/d and d/D change with time). Different classes of processes produce distinctive evolutionary tracks on an h/d versus d/D diagram. Tracks for three general classes of crater modification (processes adding material to the crater; processes redistributing the material within the crater vicinity; and processes removing the material from the crater vicinity) are calculated, and h/d and d/D ratios for craters on the earth, moon, and Mars are compared.

Schubert, G.↗
NASA NTRS1980

Some evolutionary considerations of Beta Cephei stars

The evolutionary aspects of massive population 1 stars were investigated. Semiconvection was treated in two different ways, and included mass loss both in the early as well as later spectra stages. The effect of rotation was taken into account and the time evolution of angular momentum of these models was studied. The effect of differential rotation due to the faster rotating interiors and slowed down surface layers are briefly described.

Sreennivasan, S. R.↗
NASA NTRS1979

Characterization and depositional and evolutionary history of the Apollo 17 deep drill core

With a depth resolution of about 0.5 cm, the stratigraphy of the approximately 3 m Apollo 17 deep drill core by measurement of the total FeO concentration is characterized along with the FMR surface exposure (maturity) index Is/FeO, the metallic iron concentration Fe-vsm, and the FMR linewidth delta-H. For stratigraphic characterization, the first two parameters are the most important. Most of the core is characterized by a FeO concentration of approximately 15.5 wt. %; there is a more mafic zone in the upper approximately 75 cm where the maximum FeO concentration is approximately 18.5 wt. %, and a more felsic zone between approximately 225 and 260 cm where the minimum FeO concentration is approximately 14.0%. As indicated by Is/FeO, most of the soil in the core is submature to mature; the only immature zone is located between approximately 20 and 60 cm and is one of the most distinctive features in the core. A two stage model for the depositional and evolutionary history of the Apollo 17 deep drill core is proposed: (1) deposition by one event approximately 110 m.y. ago or deposition by a sequence of closely spaced events initating a maximum of approximately 200 m.y. ago and terminating approximately 110 m.y. ago, (2) in situ reworking (gardening) to a depth of approximately 26 cm in the period between approximately 110 m.y. ago and the present day.

Morris, R. V.↗
NASA NTRS1981

The Manned Space Platform as an evolutionary means to achieve a permanent manned orbital operations facility

An evolutionary approach to permanently manned on-orbit facilities is discussed, and it is noted that the Science and Applications Manned Space Platform, which is the first step in this evolution, can be based primarily on existing and currently planned hardware. It is shown how by upgrading the systems capabilities of the Spacelab modules, the platform can be reconfigured to provide a permanent manned research and operations facility. The facility can grow in size and capability to accommodate increases in user requirements, more experiment modules, and larger crews and to provide additional power and heat rejection. It is noted that the Growth-Permanently Manned Facility can be used for science activities and/or to support various operations functions such as space construction, servicing and maintaining space systems, and vehicle assembly.

Schwartz, J. M.↗
NASA NTRS1982

Combining analysis with optimization at Langley Research Center. An evolutionary process

The evolutionary process of combining analysis and optimization codes was traced with a view toward providing insight into the long term goal of developing the methodology for an integrated, multidisciplinary software system for the concurrent analysis and optimization of aerospace structures. It was traced along the lines of strength sizing, concurrent strength and flutter sizing, and general optimization to define a near-term goal for combining analysis and optimization codes. Development of a modular software system combining general-purpose, state-of-the-art, production-level analysis computer programs for structures, aerodynamics, and aeroelasticity with a state-of-the-art optimization program is required. Incorporation of a modular and flexible structural optimization software system into a state-of-the-art finite element analysis computer program will facilitate this effort. This effort results in the software system used that is controlled with a special-purpose language, communicates with a data management system, and is easily modified for adding new programs and capabilities. A 337 degree-of-freedom finite element model is used in verifying the accuracy of this system.

Rogers, J. L., Jr.↗
NASA NTRS1982

Evolutionary space platform concept study. Volume 2, part A: SASP special emphasis trade studies

Efforts are in progress to define an approach to provide a simple and cost effective solution to the problem of long duration space flight. This approach involves a Space Platform in low Earth orbit, which can be tended by the Space Shuttle and which will provide, for extended periods of time, stability, utilities and access for a variety of replaceable payloads. The feasibility of an evolutionary space system which would cost effectively support unmanned payloads in groups, using a Space Platform which provides centralized basic subsystems is addressed.

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