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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Origins of life: a comparison of theories and application to Mars

The field of study that deals with the origins of life does not have a consensus for a theory of life's origin. An analysis of the range of theories offered shows that they share some common features that may be reliable predictors when considering the possible origins of life on another planet. The fundamental datum dealing with the origins of life is that life appeared early in the history of the Earth, probably before 3.5 Ga and possibly before 3.8 Ga. What might be called the standard theory (the Oparin-Haldane theory) posits the production of organic molecules on the early Earth followed by chemical reactions that produced increased organic complexity leading eventually to organic life capable of reproduction, mutation, and selection using organic material as nutrients. A distinct class of other theories (panspermia theories) suggests that life was carried to Earth from elsewhere--these theories receive some support from recent work on planetary impact processes. Other alternatives to the standard model suggest that life arose as an inorganic (clay) form and/or that the initial energy source was not organic material but chemical energy or sunlight. We find that the entire range of current theories suggests that liquid water is the quintessential environmental criterion for both the origin and sustenance of life. It is therefore of interest that during the time that life appeared on Earth we have evidence for liquid water present on the surface of Mars.

Review, Academic↗
NASA NTRS2010

The Roles of Tidal Evolution and Evaporative Mass Loss in the Origin of CoRoT-7 b

CoRoT-7 b is the first confirmed rocky exoplanet, but, with an orbital semimajor axis of 0.0172 au, its origins may be unlike any rocky planet in our Solar System. In this study, we consider the roles of tidal evolution and evaporative mass loss in CoRoT-7 b's history, which together have modified the planet's mass and orbit. If CoRoT-7 b has always been a rocky body, evaporation may have driven off almost half its original mass, but the mass loss may depend sensitively on the extent of tidal decay of its orbit. As tides caused CoRoT-7 b's orbit to decay, they brought the planet closer to its host star, thereby enhancing the mass loss rate. Such a large mass loss also suggests the possibility that CoRoT-7 b began as a gas giant planet and had its original atmosphere completely evaporated. In this case, we find that CoRoT-7 b's original mass probably did not exceed 200 Earth masses (about two-third of a Jupiter mass). Tides raised on the host star by the planet may have significantly reduced the orbital semimajor axis, perhaps causing the planet to migrate through mean-motion resonances with the other planet in the system, CoRoT-7 c. The coupling between tidal evolution and mass loss may be important not only for CoRoT-7 b but also for other close-in exoplanets, and future studies of mass loss and orbital evolution may provide insight into the origin and fate of close-in planets, both rocky and gaseous.

Jackson, Brian↗
NASA NTRS2021

The Origins Space Telescope: Trades and Decisions Leading to the Baseline Mission Concept

The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the universe today? How do habitable planets form? How common are life-bearing worlds? We describe how Origins was designed to answer these alluring questions. We discuss the key decisions taken by the Origins mission concept study team, the rationale for those choices, and how they led through an exploratory design process to the Origins baseline mission concept. To understand the concept solution space, we studied two distinct mission concepts and descoped the second concept, aiming to maximize science per dollar and hit a self-imposed cost target. We report on the study approach and describe the concept evolution. The resulting baseline design includes a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. The chosen architecture is similar to that of the Spitzer Space Telescope and requires very few deployments after launch. The cryo-thermal system design leverages JamesWebb Space Telescope technology and experience.

Infrared↗
NASA NTRS2021

Origins Space Telescope: From First Light to Life

The Origins Space Telescope ( Origins ) is one of four science and technology definition studies selected by National Aeronautics and Space Administration (NASA) in preparation of the 2020 Astronomy and Astrophysics Decadal survey in the US. Origins will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. It is designed to answer three major science questions: How do galaxies form stars, make metals, and grow their central supermassive black holes from reionization? How do the conditions for habitability develop during the process of planet formation? Do planets orbiting M-dwarf stars support life? Origins operates at mid- to far-infrared wavelengths from ~ 2.8 to 588 μm, is more than 1000 times more sensitive than prior far-IR missions due to its cold (~ 4.5 K) aperture and state-of-the-art instruments.

Spaceborne astrophysics↗
NASA NTRS2022

Blue Origin De-orbit Descent and Landing Tipping Point: Program Final Report

The purpose of this document is to provide a final report on the Deorbit, Descent, and Landing (DDL) Tipping Point program, a public-private partnership between Blue Origin and NASA that is partially funded by NASA contract 80LARC19C0005. In this report we summarize the results of the entire contract, including recommendations and conclusions based on the experience and results obtained. Only the portions funded by the government with associated unlimited rights are documented in detail in this report. For the work funded by Blue Origin, summaries with unlimited rights are provided for context and completeness. The Blue Origin funded work exceeded 25% of the originally proposed total program cost and included a mixture of hardware procurement and critical technology maturation. The scope of this document is a discussion of all the major tasks performed under the contract including the sensor flight demonstrations on New Shepard, the hardware in the loop lunar landing navigator demonstration, and the ground testing of the Flash LiDAR hazard sensor. The contributions from the multiple NASA teams – Johnson Space Center, Langley Research Center, Goddard Space Flight Center, and Jet Propulsion Laboratory – are described along with the contributions from Blue Origin. This document is the Final Report for statement of work item 4.1.2.10 as Deliverable 5.8.

Stefan Bieniawski↗
NASA NTRS1970

Origins of life; Proceedings of the First Conference, Princeton, N.J., May 21-24, 1967.

The dialogs on the origin of life commence with the fossil record. They deal with the age of the earth; the primitive atmosphere; precambrian microfossils; the Fig Tree series of rocks, which is part of the Swaziland system; the Bitter Springs Formation in Australia; and simulated Precambrian microfossils. The syntheses of biologically important monomers, amino acids, and nucleic acid derivatives are discussed. Polymerization mechanisms; the thermal origin of amino acid polymers; nonnucleic acid information carriers; the relationship between amino acid and nucleic acid polymers; the origin of the triple code; early reciprocating systems; and the evolution of the ribosomal system receive attention. Some brief comments on extraterrestrial life are presented. An appendix deals with the geological evidence for the thermal origin of living systems.

Margulis, L.↗
NASA NTRS1972

Lunar crater origin in the maria from analysis of Orbiter photographs.

Attempt to diagnose the origin of craters that are predominantly between 100 and 2000 m diam by the use of a statistical method that is capable of measuring both the chaining and clustering of craters. It is argued that craters with aligned centers that trend in parallel directions over vast distances are exclusively of internal origin. Strong evidence that a high proportion of the chains are of tectonic origin is found. Other criteria, such as a systematic change in the number density of craters over a test area or an excess of craters on a recent lava flow, are also used to argue for endogenic craters. Using all the data together, it is found that at least 33%, but not more than 51%, of the craters sampled are of endogenic origin. It is shown that the flux of meteoroids has not necessarily varied for the past few billion years.

Fielder, G.↗
NASA NTRS1972

Concepts related to the origin of the genetic apparatus.

Since the genetic apparatus is composed of nucleic acid and protein, the origin of the apparatus involves the origin of polyaminoacids and of polynucleotides, separately or together. Laboratory models for the origins of the separate macromolecular types are considered. The origin of their joint synthesis, believed to have been necessary at a later stage, is also discussed. Proteins and nucleic acids appear to have definite relationships with each other in three major contemporary biological systems, including chromatin, ribosomes, and the protein synthesizing system using nucleic acid templates. Stages considered in connection with the flow of information in the early evolution of the apparatus are environment, protoprotein, protein, RNA, and DNA.

Lacey, J. C., Jr.↗
NASA NTRS1974

Geochemistry and the origin of life

The origin of life on earth is examined from a viewpoint stressing the validity of the concept of chemical evolution. The different geological formations supporting the mechanisms of the theory are described; the stage of chemical evolution (preceding that of biological evolution) would have taken place from the time of the origin of the earth and meteorites, 4.6 billion years ago, to the early Precambrian period, about 3.2 billion years ago. Specific aspects of the problem discussed include amino acids from spark discharges and their comparison with the Murchison meteorite amino acids, the properties and theory of genesis of the carbonaceous complex within the cold Bokevelt meteorite, ammonion ion concentration in the primitive ocean, the oxygen isotope chemistry of ancient charts, the origin and rise of oxygen concentration in the earth's atmosphere, Precambrian microorganisms and evolutionary events prior to the origin of vascular plants, and biogenicity and significance of the oldest known stromatolites.

Kvenvolden, K. A.↗
NASA NTRS1975

Comets and planets - Their interrelated origin

This report gives a concise summary of the conclusions of cosmogonic studies linking the origin of comets with the origin of the Jovian planets at the dawn of the solar system. Cometary nuclei are shown to be original planetesimals ejected from and returning to the solar system. Formation processes for comets are described in detail, emphasizing the preplanetary rings of the Jovian planets, condensation and accretion from diffuse matter, and the origin of Oort's sphere. Physical and mechanical properties of comets are discussed, including the composition of cometary gases, the size and composition of cometary nuclei, the placement of comets in Oort's sphere, and the density of nuclei in that region. Unresolved difficulties in models of planet and comet formation are considered.

Opik, E. J.↗
NASA NTRS1983

Impact of solar system exploration on theories of chemical evolution and the origin of life

The impact of solar system exploration on theories regarding chemical evolution and the origin of life is examined in detail. Major findings from missions to Mercury, Venus, the moon, Mars, Jupiter, Saturn, and Titan are reviewed and implications for prebiotic chemistry are discussed. Among the major conclusions are: prebiotic chemistry is widespread throughout the solar system and universe; chemical evolution and the origin of life are intimately associated with the origin and evolution of the solar system; the rate, direction, and extent of prebiotic chemistry is highly dependent upon planetary characteristics; and continued exploration will increase understanding of how life originated on earth and allow better estimates of the likelihood of similar processes occurring elsewhere.

Devincenzi, D. L.↗
NASA NTRS1983

Multiple origins of life

There is some indication that life may have originated readily under primitive earth conditions. If there were multiple origins of life, the result could have been a polyphyletic biota today. Using simple stochastic models for diversification and extinction, we conclude: (1) the probability of survival of life is low unless there are multiple origins, and (2) given survival of life and given as many as 10 independent origins of life, the odds are that all but one would have gone extinct, yielding the monophyletic biota we have now. The fact of the survival of our particular form of life does not imply that it was unique or superior.

Raup, D. M.↗
NASA NTRS1990

Numerical investigation of the origin of vortex asymmetry

The flow about a slender body of revolution placed at incidence to an oncoming stream is numerically investigated for angles of attack ranging from 20 to 80 degrees and a Reynolds number of 200,000, based on freestream conditions and maximum body diameter. Navier-Stokes computations are applied to investigate the phenomena governing the onset of vortex asymmetry. Time-accurate solutions are given for an ogive-cylinder body with and without a space-fixed time-invariant disturbance added near the tip. At a 40-degree angle of attack the flow is found to be steady but becomes highly asymmetric when the disturbance is added. The level of asymmetry is dependent upon the size and location of the disturbance. It is suggested that the origin of the asymmetry is a convective-type instability of the originally symmetric flow. For higher angles of attack (60 and 80 degrees) the flow around the cylindrical part becomes unsteady, and vortex shedding is observed. It is suggested that the origin of flow unsteadiness and vortex shedding in the wake is an absolute-type instability of the originally steady flow.

Degani, David↗
NASA NTRS1990

The photochemical origins of life and photoreaction of ferrous ion in the archaean oceans

A general argument is made for the photochemical origins of life. A constant flux of free energy is required to maintain the organized state of matter called life. Solar photons are the unique source of the large amounts of energy probably required to initiate this organization and certainly required for the evolution of life to occur. The completion of this argument will require the experimental determination of suitable photochemical reactions. It is shown that biogenetic porphyrins readily photooxidize substrates and emit hydrogen in the presence of a catalyst. These results are consistent with the Granick hypothesis, which relates a biosynthetic pathway to its evolutionary origin. It has been shown that photoexcitation of ferrous ion at neutral pH with near ultraviolet light produces hydrogen with high quantum yield. This same simple system may reduce carbon dioxide to formaldehyde and further products. These reactions offer a solution to the dilemma confronting the Oparin-Urey-Miller model of the chemical origin of life. If carbon dioxide is the main form of carbon on the primitive earth, the ferrous photoreaction may provide the reduced carbon necessary for the formation of amino acids and other biogenic molecules. These results suggest that this progenitor of modern photosynthesis may have contributed to the chemical origins of life.

Mauzerall, David C.↗
NASA NTRS1991

Origin of the Uranian satellites

The current understanding of the origin of the Uranian satellites is assessed by reviewing relevant data on the Uranian satellites, including those obtained by Voyager, and comparing these properties with those of the satellites of the other outer planets. The nature of the early solar system, including the origin of the giant planets, is discussed as a preface to alternative hypotheses for the origin of the nebular disk within which the Uranian satellites formed. The chemical and physical properties of this disk are discussed, as well as the accretion of the satellites from disk solid matter. Predictions of alternative scenarios for the satellites' origin with the relevant observational constraint are compared. The orbital evolution of the larger satellites of Uranus is discussed to gain an understanding of their present orbital properties and possibly important past tidal heating episodes.

Pollack, James B.↗
NASA NTRS1992

Contradictory clues as to the origin of the Martian moons

The meager available information that is pertinent to the origin and evolution of the Martian satellites is contradictory. The known physical properties of the Martian moons (density, albedo, color and spectral reflectivity) are similar to those of many C-type asteroids, the dark 'carbonaceous' objects abundant in the outer belt but scarce near Mars; thus this line of physical evidence suggests that Phobos and Deimos are captured bodies. In contrast, calculated histories of orbital evolution due to tides in the planet and in the satellites indicate that these small craggy moons originated on nearly circular, uninclined orbits not far from their current positions; hence dynamicists prefer an origin in circum-Martian orbit. Ways are described in which these apparently contradictory viewpoints may be reconciled, although a definitive answer to the origin of the Martian satellites will almost surely have to await in situ measurements.

Burns, Joseph A.↗
NASA NTRS1993

Original size of the Vredefort structure, South Africa

The Vredefort structure is located approximately 120 km southwest of Johannesburg, South Africa, and is deeply eroded. Controversies remain on the origin of this structure with the most popular hypotheses being: (1) by impact cratering about 2.0 Ga; (2) as a cryptoexplosion structure about 2.0 Ga; and (3) by purely tectonic processes starting at about 3.0 Ga and ending with the Vredefort event at 2.0 Ga. In view of recent work in which the granophyre dikes are interpreted as the erosional remants of a more extensive impact melt sheet, injected downward into the underlying country rocks, the impact origin hypothesis for Vredefort is adopted. In order to estimate the original dimensions of the Vredefort impact structure, it is assumed that the structure was initially circular, that its predeformation center corresponds to the center of the granitic core, and that the pre-Vredefort geology of the area prior to approximately 2.0 Ga ago is as suggested by Fletcher and Reimold. The spatial relationship between shock metamorphic effects, the shock pressures they record, and the morphological features of the crater were established for a number of large terrestrial craters. The principles of crater formation at large complex impact structures comparable in size to Vredefort were also established, although many details remain unresolved. An important conclusion is that the transient crater, which is formed directly by excavation and displacement by the shock-induced cratering flow-field (i.e., the particle velocity flow field existing in the region of the transient crater but behind the initial outgoing shock front), is highly modified during the late stage processes. The original transient crater diameter lies well within the final rim of the crater, which is established by structural movements during late-stage cavity modification.

Therriault, A. M.↗
NASA NTRS1995

The Origin of Life--Did It Occur at High Temperatures

A high-temperature origin of life has been proposed, largely for the reason that the hyperthermophiles are claimed to be the last common ancestor of modern organisms. Even if they are the oldest extant organisms, which is in dispute, their existence can say nothing about the temperatures of the origin of life, the RNA world, and organisms preceding the hyperthermophiles. There is no geological evidence for the physical setting of the origin of life because there are no unmetamorphosed rocks from that period. Prebiotic chemistry points to a low-temperature origin because most biochemicals decompose rather rapidly at temperatures of 100 C (e.g., half-lives are 73 min for ribose, 21 days for cytosine, and 204 days for adenine). Hyperthermophiles may appear at the base of some phylogenetic trees because they outcompeted the mesophiles when they adapted to lower temperatures, possibly due to enhanced production of heat-shock proteins.

Miller, Stanley L.↗