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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Radiocarbon datings of Yamato meteorites

The terrestrial ages of five Yamato Meteorites were measured by the content of cosmic-ray-produced carbon-14. Three Yamato Meteorites Y-74013, Y-74097, and Y-74136, which are all diogenites, were found at sites from one to two kilometers apart from each other. Evidence is presented for these three meteorites being a single meteorite. Also presented is a method adopted in the experimental procedure which includes a check for modern carbon contamination in the meteorites.

Kigoshi, K.↗
NASA NTRS1991

Overview of cosmic rays, solar and interplanetary physics research (1987-1990)

A brief survey of recent U.S. investigations in the field of heliospheric plasmas and their manifestations is presented, introducing the following collection of detailed reviews (accessions A91-46959 to A91-46964). Topics examined include the large-scale structure of interplanetary plasmas, models of Galactic cosmic-ray production and propagation, solar-wind turbulence, long-period solar-terrestrial variability, the possible relation between solar-neutrino counts and the sunspot cycle, X-ray studies of solar flares and their implications for solar processes, and the near-sun magnetic field.

Jokipii, J. R.↗
NASA NTRS2022

CO Chondrite Parent Body Processing as Recorded by Noble Gases

**Introduction:** CO carbonaceous chondrites are among the most primitive meteorites, of which some experienced mild degrees of thermal alteration (up to 500 °C) in their parent asteroid. Previous studies on aqueously altered CM, CY and CR chondrites have shown that the noble gases preserved in those meteorites can be used to assess the extent of parent body processing. This is mostly due to an Ar-rich carrier phase being susceptible to aqueous alteration. In this study, we follow up on these findings by investigating the effects of mild thermal alteration on the noble gas content of CO chondrites. They are subclassified from petrologic subtype 3.0 (e.g., Yamato-81025) to 3.8 (e.g., Isna) according to the degree of thermal alteration experienced. Understanding these effects does not only help to distinguish the most primitive samples from the severely altered ones, but also adds to the picture of the primordial volatile composition and distribution, as preserved in the most primitive material which accreted from the solar nebula at different heliocentric distances. Additionally, we search for pairing among samples, as part of an ongoing survey of Antarctic CO chondrites. **Experimental:** Noble gas measurements were conducted on aliquots of ~20-25 mg from 16 different samples of varying petrologic subtype from 3.0 to 3.8. The gas extraction occurred in one temperature step at ~1700 °C, followed by separation into three fractions, He-Ne, Ar, and Kr-Xe, measured successively in a custom-built mass spectrometer. For each sample, complete gas extraction was verified by a re-extraction step at ~1750 °C. Details on the sample preparation and measurement protocols can be found in. **Results and Discussion:** In most cases, the gas concentrations for all five noble gases decrease with increasing petrologic subtype, and the trend is most pronounced for Ne. An exception is e.g. CO3.0 Colony, which is strongly terrestrially weathered. CO3.8 Isna shows an unusually short expo-sure time to cosmic rays (~0.15 Ma), which may be explained by a direct injection into a mean orbital resonance shortly after collision. The currently ill-defined Ar-rich carrier phase, found only in the least aqueously altered CM and CR samples, is still abundantly present in the predominately anhydrous CO chondrites, indicating that this component is less susceptible to moderately elevated temperatures. No CO chondrites examined so far contain solar wind, supporting the hypothesis that CO chondrites originate from the asteroidal interior. It thus remains enigmatic which material could account for the surface layer.

Noble gas↗
NASA NTRS1985

A study of periodicities and recurrences in solar activity and cosmic ray modulation

The 154d periodicity was found in the cosmic ray intensity (RE) vs Flares, and some other peaks of coherency in the RC vs aa sub I, that when interpreted as aliased values, might correspond to recurring interplanetary magnetic field structures and solar wind streams. It cannot be excluded, however, that some of the correspondence with aa are of terrestrial origin. This study cannot be considered exhaustive due to the fact that other solar variables, such as polar hole size, are possibly correlated to cosmic ray intensities. However, the number of observations is small so that the interpretation of the results is very difficult.

Attolini, M. R.↗
NASA NTRSDate not supplied

Moss Tolerance of Deep Space-Like Ionizing Radiation, Singular or Combined With Spaceflight Microgravity-Preparation for the BRIC-27 Experiment to the ISS

Understanding how terrestrial life perceives and tolerates deep space environments is essential to advancing human space exploration missions and searching for life beyond our solar system. Throughout evolution moss adapted to living in extreme environments from the edge of habitability. Moss inhabits areas with high UVB/UVC photon levels such as polar regions subject to ozone holes, high elevation mountain environments, and sites with elevated ionizing particle levels such as those found at nuclear plant accident sites, atomic bomb test sites or radioactive element-rich regions. We investigate if moss tolerance of ionizing radiation encounter terrestrially extends to resistance to deep space ionizing radiation. We exposed moss to high energy ion beams simulating Galactic Cosmic Ray (GCRSim) and Solar Particle Event (SPESim) (NSRL, BNL) that permeate deep space, and moss was unharmed. We also exposed moss to high doses of gamma rays as released in astrophysical events, and moss survived absorption of extremely high doses. Next, we ask if moss tolerance of deep space-like ionizing radiation observed terrestrially differs from that in other deep space environments. In the upcoming BRIC-27 spaceflight experiment we will sequentially expose Antarctic moss C.purpureus to GCRSim and SPESim followed by exposure to spaceflight microgravity and compare gene expression profiles in deep space-like ionizing radiation, singular or combined with spaceflight microgravity. Additionally, we will compare gene expression profiles in spaceflight microgravity, singular or combined with deep space-like ionizing radiation. Hence, BRIC-27 will advance our understanding of the combined effects of both deep space ionizing radiation and microgravity, which may have different and more profound effects on plant physiology and performance than each condition separately.

Agata Klaudia Zupanska↗
NASA NTRS1987

Cosmic-ray-produced neon and helium in the summit lavas of Maui

The identification of cosmic-ray-produced Ne-21c in addition to He-3c, components attributed to cosmic ray-induced spallation reactions, are reported in gases extracted by fusion of olivines and clinopyroxenes after vacuum-crushing. The observed (He-3/Ne-21)c ratios and the ratio of Ne-21c in olivine to that in clinopyroxene are consistent with an in situ origin of He-3c and Ne-21c by cosmic-ray spallation reactions. These components could be important for interpreting helium isotopic data in terrestrial reservoirs. Geophysical applications could include determinations of erosion rates and exposure histories of terrestrial rocks.

Marti, K.↗
NASA NTRS2024

Terrestrial Ages and Pairing of Howardites, Eucrites and Diogenites From the Miller Range Icefields, Antarctica

In the past 45 years, the US Antarctic Meteorite (ANSMET) program has recovered more than 22,000 meteorites from more than 50 individual meteorite stranding areas. Although the Antarctic meteorite collection is dominated by ordinary chondrites which represent 80-90% of the recovered samples, it also contains many achondrites, including howardites, eucrites and diogenites, which are collectively known as HED meteorites. A challenge for the Antarctic meteorite collection is to identify paired fragments that belong to the same fall. Eight ANSMET field sea-sons at the Miller Range Icefields (MIL), a series of blue ice fields about 40 km long and 10-20 km wide, have yielded more than 3000 meteorites including 56 HEDs. At least three possible pairing groups (with 3-10 members each) were initially identified among the MIL diogenites and one each among the howardites and eucrites. Since many HED meteorites are heterogeneous breccias, pairing identifications based on cm-sized samples is difficult and other independent evidence is needed to verify these proposed pairings, as was shown for several Antarctic howardite pairing-groups. Here we re-examine pairings of HED’s from the Miller Range Icefields, using multiple lines of evidence, including texture/petrography, chemical composition, cosmogenic radionuclides and find locations. Due to the heterogeneous nature of HED meteorites, we will not only consider pairings strictly among the three HED groups, but will also consider pairing of howardites with brecciated eucrites or brecciated diogenites if the cosmogenic nuclides, texture and chemical compositions support this. The concentrations of cosmogenic radionuclides in meteorites are a function of the cosmic-ray exposure (CRE) age, shielding conditions (size and irradiation depth), chemical composition, as well the terrestrial age of the meteorite sample. Since the production rates of cosmogenic nuclides as a function of meteoroid size, depth and composition are well understood [6], their measured concentrations can be used to determine which meteorites belong to the same fall even if the chemical composition of the samples show significant variations. We selected 28 of the 56 HED samples from the MIL collection, including 12 diogenites, 8 howardites and 8 brecciated eucrites to investigate pairing relationships.

howardite↗
NASA NTRS1986

Cosmic ray records in Antarctic meteorites

The cosmogenic radionuclides Be(10), Al(26), and Mn(53) and noble gases were determined in more than 28 meteorites from Antarctica by nuclear analytical techniques and static mass spectrometry, respectively. The summarized results are listed. The concentrations of Al(26) and Mn(53) are normalized to the repective main target elements and given in dpm/kg Si sub eq and dpm/kg Fe. The errors stated include statistical as well as systematical errors. For noble gas concentrations estimated errors are 5% and for isotopic ratios 1.5%. Cosmic ray exposure ages T sub 21 were calculated by the noble gas concentrations and the terrestrial residence time (T) on the basis of the spallogenic nuclide Al(26). The suggested pairing of the LL6 chondrite RKPA 80238 and RKPA 80248 and the eucrites ALHA 76005 and ALHA 79017 is confirmed not only by the noble gas data but also by the concentrations of the spallation produced radionuclides. Futhermore, ALHA 80122, clasified as an H6 chondrite, has a noble gas pattern which suggest that this meteorite belongs to the ALHA 80111 shower.

Vogt, S.↗
NASA NTRS1992

The breakup of a meteorite parent body and the delivery of meteorites to earth

Whether many of the 10,000 meteorites collected in the Antarctic are unlike those falling elsewhere is contentious. The Antarctic H chondrites, one of the major classes of stony meteorites, include a number of individuals with higher induced thermoluminescence peak temperatures than observed among non-Antarctic H chondrites. The proportion of such individuals decreases with the mean terrestrial age of the meteorites at the various ice fields. These H chondrites have cosmic-ray exposure ages of about 8 million years, experienced little cosmic-ray shielding, and suffered rapid postmetamorphic cooling. Breakup of the H chondrite parent body, 8 million years ago, may have produced two types of material with different size distributions and thermal histories. The smaller objects reached earth more rapidly through more rapid orbital evolution.

Benoit, Paul H.↗
NASA NTRS1993

Recovery of interplanetary cosmic ray intensity following the great Forbush decrease of mid-1991

There was a succession of major solar flares in late-May to mid-June 1991. Their effects on cosmic ray intensity were observed by six spacecraft at various points in the heliosphere and by terrestrial neutron monitors. Study of these observations is summarized as followed: (1) An abrupt and extraordinarily large Forbush decrease in intensity occurred at the Earth on day of year (DOY) 164/1993 (13 June) and ones of similar magnitude (approximately equal 20 percent) occurred in an orderly sequence of timing thereafter over ranges of heliocentric ecliptic longitude of essentially 360 degrees; of heliographic latitude +32 degrees to -5 degrees; and of radial distance 1.0 to 53 AU. (2) The apparent radial speed of propagation of the presumably causative blast wave was 865 (+/- 75)km/s. (3) It appears likely that the distinctive solar flare of DOY 162/1991 (11 June) was the dominant cause of the blast wave. Two different representations of the subsequent recoveries of intensity yield substantially different numerical values of 'recovery time' but either set of values shows an increase by a factor of about three between 1.0 and 53 AU.

Van Allen, James A.↗
NASA NTRS2011

Preface for the ILWS Special Issue of JASTP

During the week of October 4-9,2009, about 160 participants from 19 countries met at the Itamambuca resort area of Ubatuba, Sao Paulo, Brazil to discuss the "Influence of solar variability on geophysical and heliospheric phenomena" Conference, organized by the International Living With a Star (ILWS) Program of NASA and by the National Institute of Space Research (INPE) of Brazil. This special issue collects 38 papers from that Conference, with 3 papers dealing with solar topics, 12 with interplanetary and cosmic rays,12 with magnetospheric, 9 with the low-latitude ionosphere and 2 with solar terrestrial system and climate. Furthermore six of the review papers presented at that Conference are being published in a special issue of the SpaceScience Reviews journal. The combined ensemble of papers describes the complex series of phenomena that link the Sun to the Earth.

Gonzalez, Walter D.↗
NASA NTRS1986

Cosmogenic helium in a terrestrial igneous rock

New helium isotopic measurements on samples from the Kula formation of Haleakala volcano of Hawaii are presented that are best explained by an in situ cosmogenic origin for a significant fraction of the He-3. Results from crushing and stepwise heating experiments, and consideration of the exposure age of the sample at the surface and the cosmic ray fluxes strongly support this hypothesis. Although crustal cosmogenic helium has been proposed previously, this represents its first unambiguous identification in a terrestrial sample.

Kurz, M. D.↗
NASA NTRS1971

Neutron capture on Sm-149 in lunar samples.

High precision isotopic composition measurements of Sm have been carried out for two terrestrial and seven lunar samples from three Apollo sites. The lunar samples, selected to show a wide variation in cosmic ray exposure ages, have a wide range of enrichments in Sm-150/Sm-154 (up to 0.8%) and depletions in Sm-149/Sm-154 which are due to neutron capture. The ratio of the number of neutrons captured per atom by Sm-149 to Gd-157 is 0.9 and reflects a hardened lunar neutron spectrum. This ratio is in reasonable but not exact agreement with that obtained from the theoretical lunar neutron energy spectrum of Lingenfelter, Canfield and Hampel. The average composition for terrestrial samarium is given.

Russ, G. P., III↗
NASA NTRS1972

Solar wind rare gas analysis: Trapped solar wind helium and neon in Surveyor 3 material

The He-4 and Ne-20 contents in sections of the Surveyor 3 support strut samples were determined by optical and scanning electron microscopy and are compared to the results of the Apollo solar wind composition (SWC) experiments. The He-4/Ne-20 ratio in the samples from the sunlit side of the strut was approximately 300; the ratios determined in Apollo 12 lunar fines and SWC foil were below 100. The He-4/He-3 ratios were also determined, and the ratio obtained from Surveyor 3 material is higher than those found with Apollo 11 and 12 SWC experiments. The effects of spallation by cosmic rays or solar protons, stripping by cosmic ray or energetic solar alpha particles, recycling of solar wind He and radiogenic Ne, He from terrestrial atmosphere, mass discrimination near the moon, mass dependence of trapping probability, diffusion, and contamination by lunar dust are considered.

Buehler, F.↗
NASA NTRS1969

Diurnal variation in low-energy cosmic ray cutoffs.

Balloon observations are presented of the daily variation in the flux of nuclear γ-rays which were produced by proton bombardment of the terrestrial atmosphere over Byrd Station, Antarctica ( L ≈ 7) during the January–February 1967 solar particle events. This modulation is interpreted as the result of a local geomagnetic-time dependence for the cutoff of the solar proton influx at low energies (≈ 1–30 MeV). The observations are compared with predictions of existing theory and, while the predicted effect is confirmed qualitatively, significant discrepancies in quantitative detail are evident. Lack of better agreement lies, most probably, in the assumed simplicity of the magnetospheric models presently in use.

J R Barcus↗
NASA NTRS1980

Late Eocene rings around the earth

The suggestion of O'Keefe (1980) that the terminal Eocene event was caused by rings of tektite material encircling the earth is discussed. It is argued that the assumption that the tektites are of lunar volcanic origin is unwarranted and contrary to existing data, including the lack of lunar rocks of suitable composition, the lack of lunar rocks of the correct age, the lack of evidence that the North American tektites fell throughout a sedimentary rock column of a few million years, and the nondetection of a tektite with a measurable cosmic ray exposure age. Alternatively, it is suggested that the terminal Eocene event may be associated with volcanic ash, air-fall tuff and bentonite in the late Eocene. O'Keefe replies that the hypothesis of the terrestrial origin of the tektites conflicts with the laws of physics, for example in the glass structure and shaping of the tektites. Furthermore, evidence is cited for lunar rocks of the proper major-element composition and ages, and it is noted that the proposed solar Poynting-Robertson effect would account for the particle fall distributions and cosmic ray ages.

King, E. A.↗
NASA NTRS1976

Solar cycle review /General aspects/

Several topics are discussed in this review of the solar cycle. The basic solar-interplanetary magnetic structure is considered, and the high speed solar wind streams and their sunspot cycle variation are described, with attention to the sunspot cycle variation, the high speed solar wind streams and geomagnetic disturbances, and the causes of changes of the north-south component of the interplanetary magnetic field. Solar storms, solar flares, and magnetic bubbles are examined with attention directed to the solar cycle variation of transient polar activities and the interplanetary disturbances associated with solar storms. Some features of cosmic rays, the 11-year cycle variation and the Forbush decreases, are considered. Attention is also directed to the terrestrial atmosphere and to the outer planets and their relation to the solar cycle.

Akasofu, S.-I.↗