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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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Braking effect on axial rotational behavior of main sequence stars and plausible formation of planetary system from nebula
Nuclear reactions replacing gravitational contraction as major source of stellar luminosity for model stars and approach to main sequence
Mechanism of lithium depletion in main sequence stars of solar type with involvement of substantial amount of convective overshoot
Evolution of three solar mass star from main sequence to red giant
Integrated circuit sequence generator for coded pulse radar systems
Information content of q-level m-sequences restricted to sums of n - analysis of enumeration, encoding, and decoding problems
Evolution of 5 solar masses star model from main sequence through core helium burning compared to 3 solar masses model, noting Hertzsprung-Russell diagram
Model atmospheres of class M main sequence stars use to study absorption bands of TiO
Although the evolution of protein-coding sequences within genomes is well understood, the same cannot be said of the cis-regulatory regions that control transcription. Yet, changes in gene expression are likely to constitute an important component of phenotypic evolution. We simulated the evolution of new transcription factor binding sites via local point mutations. The results indicate that new binding sites appear and become fixed within populations on microevolutionary timescales under an assumption of neutral evolution. Even combinations of two new binding sites evolve very quickly. We predict that local point mutations continually generate considerable genetic variation that is capable of altering gene expression.
Viable bacteria were found in permafrost core samples from the Kolyma-Indigirka lowland of northeast Siberia. The samples were obtained at different depths; the deepest was about 3 million years old. The average temperature of the permafrost is -10 degrees C. Twenty-nine bacterial isolates were characterized by 16S rDNA sequencing and phylogenetic analysis, cell morphology, Gram staining, endospore formation, and growth at 30 degrees C. The majority of the bacterial isolates were rod shaped and grew well at 30 degrees C; but two of them did not grow at or above 28 degrees C, and had optimum growth temperatures around 20 degrees C. Thirty percent of the isolates could form endospores. Phylogenetic analysis revealed that the isolates fell into four categories: high-GC Gram-positive bacteria, beta-proteobacteria, gamma-proteobacteria, and low-GC Gram-positive bacteria. Most high-GC Gram-positive bacteria and beta-proteobacteria, and all gamma-proteobacteria, came from samples with an estimated age of 1.8-3.0 million years (Olyor suite). Most low-GC Gram-positive bacteria came from samples with an estimated age of 5,000-8,000 years (Alas suite).
This paper discusses techniques for parameterizing routine operations using onboard blocks. The relationship between one-use sequences and reusable blocks is discussed.
We discusses the properties of the immediate circumstellar environment of pre-main-sequence stars of intermediate mass, with particular emphasis of the properties and evolution of the circumstellar disks.
Following launch the TOPEX/Poseidon flight team began a complex sequence of maneuvers to place the TOPEX/Poseidon satellite in it's operational orbit.
TOPEX/POSEIDON....was launched...on August 10, 1992...The Project wanted to achieve operational orbit as soon as possible in order to begin oceanographic data acquisition through altimeters. A sequence of six manuevers was implemented to acquire the operational orbit following injection...
Making certain that spacecraft command sequences do not violate any constraints is often tedious and expensive in terms of both personnel and software development. To reduce this cost, we have pursued the development of a flexible system for specifying models of spacecraft behavior in response to commands as well as constraints on that behavior. The potential need for modeling complex spacecraft behavior required that the system be designed to be usable both on a conventional workstation and a parallel supercomputer. Finally, it needed to be intuitive enough for the the intended mission operations users to easily design sets of rules and models to automate tedious, resource-consuming constraint checking of commands. We have defined a Specification And Verification Environment (SAVE) for spacecraft flight rules.
We investigate the application of conditional sequencing to robot navigation.
VMlib is a C++ library for visualizing spacecraft mission simulations with an emphasis on the execution of observation sequences.
The Rover Sequencing and Visualization Program is a suite of toos for the commanding of planetary rovers which are subject to significant light time delay and thus are unsuitable for tele-operation.