Integrated palynology and sequence stratigraphy of the upper Cretaceous (Maastrichtian) strata, Rio Grande Embayment, Texas, using well, outcrop, and seismic data

NASA Astrophysics Data System (ADS)

Mahmoud, Salah El-Din Ragab

Numerous nomenclature problems surround the Campanian and Maastrichtian strata of the Rio Grande Embayment. Sellards et al. (1932) and Stephenson et al. (1942) placed the Upson Clay and San Miguel Formation in the Taylor Group (Campanian). These workers assigned the overlying Olmos Coal and the Escondido Formation to the Navarro Group (Maastrichtian). Pessagno (1969, p. 90--91) tentatively included the Upson Clay, the San Miguel Formation, the Olmos Coal, and the Escondido Formation in the Navarro Group, but noted that these strata are lithologically dissimilar to those of the type Navarro Group in Navarro County (northeast Texas). He (ibid, p. 91) suggested that "---Future workers should consider the possibility of excluding the entire sequence from the Navarro Group. It is perhaps more closely related to the Difunta Group of Mexico or deserves a group name of its own." Pessagno (1967; 1969, p. 91--92) utilized planktonic foraminiferal biostratigraphic data to determine (1) that the Upson Clay and San Miguel Formation are assignable to the lower Maastrichtian and (2) that the Escondido Formation is assignable to the upper Maastrichtian. The present investigation attempts to build on the chronostratigraphic framework established by Pessagno (1967, 1969). Palynology is used for the first time in this report to generate biostratigraphic, chronostratigraphic, and paleoecological data for the Maastrichtian strata in the study area. New palynological data, integrated with existing planktonic foraminifera and megafossils, indicate that San Miguel Formation and Olmos Coal are of Maastrichtian age. Tying results with seismic data results in dating interpreted sequence boundaries to be within the time interval of 83 and 63 MA. Five seismic facies are delineated and a rate of sediment supply higher than the rate of subsidence during a prolonged progradational episode is suggested in the study area. Three-dimensional seismic data are interpreted in terms of the structure and

First evidence of Hadrosauropodus in Gondwana (Yacoraite Formation, Maastrichtian-Danian), northwestern Argentina

NASA Astrophysics Data System (ADS)

Díaz-Martínez, Ignacio; de Valais, Silvina; Cónsole-Gonella, Carlos

2016-10-01

Uppermost Cretaceous (Campanian-Maastrichtian) large ornithopod tracks are scarce in Gondwana. This record is limited to few citations in the northern Argentina, Peru and possibly Bolivia, although their ichnological affinities are still under discussion. Recently, a new vertebrate tracksite with large ornithopod tracks has been found in the Maimará locality, Jujuy province, Argentina, from the Yacoraite Formation (Maastrichtian-Danian). The best preserved track is characterized by having large and bilobed heel impression and wide and short digit impressions with blunt claw marks. This record represents the unambiguous record of large ornithopod tracks in Gondwana in the Uppermost Cretaceous, and its features allow classifying it as Hadrosauropodus. Previously, this ichnotaxon had exclusively Laurasian distribution. Therefore, this record is the first evidence of Hadrosauropodus from Gondwana expanding the geographic range of this ichnogenus. A member of Hadrosauridae is reinforced as possible trackmaker of the Hadrosauropodus tracks. Uppermost Cretaceous hadrosaurid dinosaurs are scarce in Gondwana, being the record limited to Patagonia, La Pampa province and Antarctica. Therefore, the Maimará tracks increase the knowledge of this kind of dinosaur from Gondwana.

The δ13C record of Maastrichtian-Paleocene oil shales from Jordan - Stratigraphic and environmental implications for an epicontinental setting

NASA Astrophysics Data System (ADS)

Beik, Ibtisam; Gómez, Victor Giraldo; Podlaha, Olaf G.; Mutterlose, Jörg

2018-07-01

Organic matter (OM) rich marls were deposited in several intrashelf basins in Jordan (e.g. Yarmouk Basin, Lajjun Basin, Azraq-Hamza Basin, Jafr Basin, Eshidiyya Basin) on the southeastern Tethyan margin during the Maastrichtian to middle Eocene. Factors like surface water productivity fueled by upwelling and sea level changes affected their deposition. Potential effects of climatic changes have not been determined yet. We present the first stable carbon and oxygen isotope records of Maastrichtian-Danian oil shales from the Azraq-Hamza and Jafr Basins in south- and central-east Jordan. The δ13Ccarb curves were time-calibrated based on calcareous nannofossil biostratigraphy. Eight notable excursions were identified in the Jordanian Maastrichtian sections. These were correlated with the documented Maastrichtian δ13Ccarb events in the (sub) tropical sections of Italy and the western Pacific: the Campanian-Maastrichtian boundary Events 4 and 5 (CMBE-4, CMBE-5), the Middle Maastrichtian Events 1 to 3 (MME-1 to MME-3) and the Cretaceous-Paleogene boundary Events 1 to 3 (KPgE-1 to KPgE-3). Signs of the Latest Danian Event (LDE) were recognized as well. Total organic carbon (TOC) data exhibit a complex relationship with the δ13Ccarb proxy record. The δ13Ccarb signals are repeatedly dampened due to the OM oxidation and subsequent 12C release. The effect of short term climate changes is observed, but is not always straight forward. Long term climate changes had indirect effects on bottom water oxygenation and OM preservation via sea level changes. The δ18Ocarb data from both sections reveal minor temperature changes in the Maastrichtian. Slight warming is observed in the MME interval. A potential increase of the paleotemperature is reported from the Azraq-Hamza section occurring in the latest Maastrichtian to earliest Danian.

Absolute paleobathymetry of Upper Cretaceous chalks based on ostracodes - Evidence from the Demopolis Chalk (Campanian and Maastrichtian) of the northern Gulf Coastal Plain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puckett, T.M.

1991-05-01

The presence of abundant and diverse sighted ostracodes in chalk and marl of the Demopolis Chalk (Campanian and Maastrichtian) in Alabama and Mississippi strongly suggests that the Late Cretaceous sea floor was within the photic zone. The maximum depth of deposition is calculated from an equation based on eye morphology and efficiency and estimates of the vertical light attenuation. In this equation, K, the vertical light attenuation coefficient, is the most critical variable because it is the divisor for the rest of the equation. Rates of accumulation of coccoliths during the Cretaceous are estimated and are on the same ordermore » as those in modern areas of high phytoplankton production, suggesting similar pigment and coccolith concentrations in the water column. Values of K are known for a wide range of water masses and pigment concentrations, including areas of high phytoplankton production; thus light attenuation through the Cretaceous seas can be estimated reliably. Waters in which attenuation is due only to biogenic matter-conditions that result in deposition of relatively pure chalk-have values of K ranging between 0.2 and 0.3. Waters rich in phytoplankton and mud-conditions that result in deposition of marl-have K values as great as 0.5. Substituting these values for K results in depth range of 65 to 90 m for deposition of chalk and depth of 35 m for deposition of marl. These depth values suggest that deposition of many Cretaceous chalks and marls around the world were deposited under relatively shallow conditions.« less

Early Campanian coastal progradational systems and their coal-forming environments, Wyoming to New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marley, W.E.; Flores, R.M.; Ethridge, F.G.

1985-05-01

Ammonite zones (Baculites obtusus-Scaphites hippocrepis) in the marine facies associated with the Mesaverde Formation in the Bighorn basin, Wyoming, Star Point Sandstone and Blackhawk Formation in the Wasatch Plateau, Utah, and the Point Lookout Sandstone, Menefee Formation, and Crevasse Canyon Formation in the Gallup coalfield, New Mexico, indicate that these formations were deposited during early Campanian time (80-84 Ma). The coal-forming environments of these early Campanian formations were located landward of wave-reworked coastal sand complexes of progradational systems along the western margin of the Cretaceous seaway from Wyoming to New Mexico. The Mesaverde coals accumulated in swamps of the lowermore » delta plain and coeval interdeltaic strandplain environments. The Star Point-Blackhawk coals accumulated in swamps of the lower delta plains of laterally shifting, prograding deltas and associated barrier ridge plains. The Point Lookout, Menefee, and Crevasse canyon coals formed in swamps of the lower delta plain and infilled lagoons behind barrier islands. Although the common coal-forming environments of these progradational systems are back barrier and delta plain, the former setting was the more conducive for accumulation of thick, laterally extensive coals. Economic coal deposits formed in swamps built on abandoned back-barrier platforms that were free of detrital influx and marine influence. Delta-plain coals tend to be lenticular and laterally discontinuous and thus uneconomic. The early Campanian coal-forming coastal-plain environments are analogous to modern peat-forming environments along the coast of Belize, Central America. Deltaic sediments deposited along the Belize coast by short-headed streams are reworked by waves into coastal barrier systems.« less

A new species of Peritresius Leidy, 1856 (Testudines: Pan-Cheloniidae) from the Late Cretaceous (Campanian) of Alabama, USA, and the occurrence of the genus within the Mississippi Embayment of North America

PubMed Central

Parham, James F.; Ehret, Dana J.; Ebersole, Jun A.

2018-01-01

Late Cretaceous members of Peritresius belong to a diverse clade of marine adapted turtles currently thought to be some of the earliest representatives of the lineage leading to modern hard-shelled sea turtles (Pan-Cheloniidae). Prior studies have suggested that Peritresius was monospecific, with a distribution restricted to Maastrichtian deposits in North America. However, new Peritresius specimens identified from Alabama and Mississippi, USA, show that the genus contains two taxa, Peritresius ornatus, and a new species Peritresius martini sp. nov. These two taxa are characterized by the presence of a generally cordiform carapace with moderately serrated peripherals, well-developed ventral flanges beginning at the third peripheral, squarish umbilical and lateral plastral fontanelles, and a narrow bridge formed by the contact between the hyoplastron and hypoplastron. Peritresius martini sp. nov. can be distinguished by its lack of dermal ornamentation and the presence of a ‘rib-free’ 10th peripheral. These new specimens represent the first occurrences of Peritresius from the Late Cretaceous Mississippi Embayment and extend the temporal range of this genus back to the early Campanian. When tested within a global phylogenetic context, Peritresius is placed on the stem of Cheloniidae (Pan-Cheloniidae) along with Ctenochelys and Allopleuron hofmanni. The heavily vascularized and uniquely sculptured dermal elements of P. ornatus are interpreted here as potentially relating to thermoregulation and therefore may have been one of the key factors contributing to the survival of Peritresius into the Maastrichtian, a period of cooling when other lineages of Campanian marine turtles (e.g., Protostegids, Toxochelys, and Ctenochelys) went extinct. PMID:29668704

Geodynamic Evolution of Northeastern Tunisia During the Maastrichtian-Paleocene Time: Insights from Integrated Seismic Stratigraphic Analysis

NASA Astrophysics Data System (ADS)

Abidi, Oussama; Inoubli, Mohamed Hédi; Sebei, Kawthar; Amiri, Adnen; Boussiga, Haifa; Nasr, Imen Hamdi; Salem, Abdelhamid Ben; Elabed, Mahmoud

2017-05-01

The Maastrichtian-Paleocene El Haria formation was studied and defined in Tunisia on the basis of outcrops and borehole data; few studies were interested in its three-dimensional extent. In this paper, the El Haria formation is reviewed in the context of a tectono-stratigraphic interval using an integrated seismic stratigraphic analysis based on borehole lithology logs, electrical well logging, well shots, vertical seismic profiles and post-stack surface data. Seismic analysis benefits from appropriate calibration with borehole data, conventional interpretation, velocity mapping, seismic attributes and post-stack model-based inversion. The applied methodology proved to be powerful for charactering the marly Maastrichtian-Paleocene interval of the El Haria formation. Migrated seismic sections together with borehole measurements are used to detail the three-dimensional changes in thickness, facies and depositional environment in the Cap Bon and Gulf of Hammamet regions during the Maastrichtian-Paleocene time. Furthermore, dating based on their microfossil content divulges local and multiple internal hiatuses within the El Haria formation which are related to the geodynamic evolution of the depositional floor since the Campanian stage. Interpreted seismic sections display concordance, unconformities, pinchouts, sedimentary gaps, incised valleys and syn-sedimentary normal faulting. Based on the seismic reflection geometry and terminations, seven sequences are delineated. These sequences are related to base-level changes as the combination of depositional floor paleo-topography, tectonic forces, subsidence and the developed accommodation space. These factors controlled the occurrence of the various parts of the Maastrichtian-Paleocene interval. Detailed examinations of these deposits together with the analysis of the structural deformation at different time periods allowed us to obtain a better understanding of the sediment architecture in depth and the delineation of

Global aspects of dinosaur distribution and evolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sues, H.

1988-02-01

Late Jurassic dinosaurian assemblages show close taxonomic correspondence over wide geographical ranges. Presently available if meager evidence suggests that this is also the case for Early Cretaceous communities. Cretaceous dinosaurian assemblages of Campanian and Maastrichtian age show considerable geographical differentiation but also some wide-ranging genera. Northern Hemisphere terrestrial ecosystems were dominated by hadrosaurs and ceratopsians, both herbivores with advanced capabilities for oral food-processing, whereas Southern Hemisphere biota were characterized by the abundance of titanosaurid sauropods, which relied on gut processing. Very close taxonomic similarities exist between the Campanian and early Maastrichtian dinosaurian assemblages of Mongolia and western North America, which,more » in part, is matched by similarities among other tetrapods such as mammals. Endemic dinosaurs in the Southern Hemisphere appear to reflect major changes in continental configuration. Some evidence exists for interchange of fuanal elements between North and South America. In absence of late Maastrichtian dinosaurian assemblages from most regions, scenarios concerning the terminal Cretaceous extinction of the Dinosauria should be regarded with caution because they are exclusively based on the conditions in western North America.« less

The benthic fauna from the lower Maastrichtian chalk of Kronsmoor (Saturn quarry, northern Germany): composition and palaeoecologic implications

NASA Astrophysics Data System (ADS)

Engelke, Julia; Linnert, Christian; Mutterlose, Jörg; Wilmsen, Markus

2017-04-01

abundances in the upper part are recognised. The palaeoecological analysis of both datasets indicates different guilds, of which epifaunal suspension feeders (fixo-sessile and libero-sessile guilds), comprising c. 50 % of the fauna in the lower interval, increase to a dominance of c. 80 % in the upper interval, including a considerable proportion of rhynchonelliform brachiopods. The palaeoecological data of benthic communities at Kronsmoor are indicative of increased nutrient availability during the early Maastrichtian. However, in the absence of any evidence of increased productivity in the overlying photic zone (calcareous nannofossil data), a lateral input (upwelling) of nutrient-rich waters onto the shelf to fuel the benthic ecosystem has to be considered. This view is supported by records of contemporaneous changes in latest Cretaceous ocean circulation that followed the latest Campanian cooling event, inclusive of a southward spread of waters of intermediate depth from high-latitudes.

Lilliput effect in a retroplumid crab (Crustacea: Decapoda) across the K/Pg boundary

NASA Astrophysics Data System (ADS)

Martínez-Díaz, José Luis; Phillips, George E.; Nyborg, Torrey; Espinosa, Belinda; Távora, Vladimir de Araújo; Centeno-García, Elena; Vega, Francisco J.

2016-08-01

The genus Costacopluma (Brachyura: Decapoda: Retroplumidae) had a wide distribution during the early Paleogene and is currently represented by 14 species across the Late Cretaceous and early Paleogene. Described early Paleogene species have a smaller mean body size compared to Campanian-Maastrichtian populations of Africa, northeastern Mexico, and southeastern United States. Originally described from the Paleocene and Eocene of Alabama, Costacopluma grayi Feldmann and Portell, 2007, is now documented from the uppermost Maastrichtian (66.2 Ma) of northeastern Mexico and Mississippi and Lower Paleocene of Arkansas, all representing medium size specimens. The morphological features of latest Maastrichtian (66.2 Ma) individuals are identical to those observed among populations of C. grayi from the Paleogene of Alabama and Arkansas, which have a smaller mean size. This size reduction, or dwarfism, in C. grayi across the K-Pg boundary is an example of the Lilliput effect. Dwarfism has been documented in several invertebrate groups as a response to environmental stress, but this is the first record of the Lilliput effect in brachyuran crustaceans. The stratigraphic and geographic range for Costacopluma mexicana Vega and Perrilliat, 1989, is extended to the upper Campanian in northeastern Mexico and lower Maastrichtian in Mississippi and is suggested as a possible ancestor of C. grayi. Different preservational modes for this species in northeastern Mexico are discussed.

The biostratigraphy and paleogeography of Maastrichtian inoceramids

NASA Technical Reports Server (NTRS)

Macleod, K. G.; Huber, B. T.; Ward, P. D.

1994-01-01

The global distribution of Maastrichtian inoceramids is now known in enough detail that the patterns of disappearance can be used to place first-order constraints on paleoceanographic changes that may have occurred during that age. The Inoceramidae is an excellent group to focus on in a study of Maastrichtian events for the following reasons: (1) they were globally distributed in the early Maastrichtian; (2) they did not survive the age (i.e., they undergo change during the interval); and (3) they have left a rich microfossil and macrofossil record. Some inoceramids grew to be very large; however, even the largest often passively disaggregated and are preserved as hundreds of millions of characteristic, columnar, polygonal prisms of calcite approximately 100 microns across. This taphonomic process has greatly increased the inoceramid fossil record and provides a means of objectively estimating changes in their standing population. In addition, because these prisms commonly occur in Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) cores, it is relatively easy to generate a truly global database. The existing macrofossil record of inoceramids has less temporal and spacial resolution but greater taxonomic resolution than the microfossil record. In concert the microfossil and macrofossil records of inoceramids demonstrate that important changes occurred during the Maastrichtian. These changes are distinct from the KT boundary catastrophe but are part of the larger KT transition.

Late Cretaceous restructuring of terrestrial communities facilitated the end-Cretaceous mass extinction in North America.

PubMed

Mitchell, Jonathan S; Roopnarine, Peter D; Angielczyk, Kenneth D

2012-11-13

The sudden environmental catastrophe in the wake of the end-Cretaceous asteroid impact had drastic effects that rippled through animal communities. To explore how these effects may have been exacerbated by prior ecological changes, we used a food-web model to simulate the effects of primary productivity disruptions, such as those predicted to result from an asteroid impact, on ten Campanian and seven Maastrichtian terrestrial localities in North America. Our analysis documents that a shift in trophic structure between Campanian and Maastrichtian communities in North America led Maastrichtian communities to experience more secondary extinction at lower levels of primary production shutdown and possess a lower collapse threshold than Campanian communities. Of particular note is the fact that changes in dinosaur richness had a negative impact on the robustness of Maastrichtian ecosystems against environmental perturbations. Therefore, earlier ecological restructuring may have exacerbated the impact and severity of the end-Cretaceous extinction, at least in North America.

Late Cretaceous restructuring of terrestrial communities facilitated the end-Cretaceous mass extinction in North America

PubMed Central

Roopnarine, Peter D.; Angielczyk, Kenneth D.

2012-01-01

The sudden environmental catastrophe in the wake of the end-Cretaceous asteroid impact had drastic effects that rippled through animal communities. To explore how these effects may have been exacerbated by prior ecological changes, we used a food-web model to simulate the effects of primary productivity disruptions, such as those predicted to result from an asteroid impact, on ten Campanian and seven Maastrichtian terrestrial localities in North America. Our analysis documents that a shift in trophic structure between Campanian and Maastrichtian communities in North America led Maastrichtian communities to experience more secondary extinction at lower levels of primary production shutdown and possess a lower collapse threshold than Campanian communities. Of particular note is the fact that changes in dinosaur richness had a negative impact on the robustness of Maastrichtian ecosystems against environmental perturbations. Therefore, earlier ecological restructuring may have exacerbated the impact and severity of the end-Cretaceous extinction, at least in North America. PMID:23112149

Equivalent radiolarian ages from ophiolitic terranes of Cyprus and Oman

USGS Publications Warehouse

Blome, Charles D.; Irwin, William P.

1985-01-01

Radiolarian biostratigraphy shows that umberiferous strata overlying the Troodos ophiolite in Cyprus are Turonian in age and are thus essentially contemporaneous with similar strata that overlie the Samail ophiolite in Oman. However, this radiolarian age is markedly older than Campanian isotopic ages measured on the underlying rocks of the Troodos ophiolite. The revised age for the umbers indicates that the Troodos lavas were formed no later than Turonian time. The presence of overlying autochthonous Maastrichtian chalks restricts the emplacement of the Troodos ophiolite to the Late Cretaceous (Santonian to early Maastrichtian).

Albian-Paleocene flora of the north pacific: Systematic composition, palaeofloristics and phytostratigraphy

NASA Astrophysics Data System (ADS)

Herman, A. B.

2013-12-01

Principal attention is focused on phytostratigraphy and comparative palaeofloristics of the Anadyr-Koryak (AKSR) and Northern Alaska (NASR) subregions of the North Pacific Region. The high-resolution Upper Albian-Paleocene phytostratigraphic schemes of these subregions are based on perceived stages of their floral evolution. In the AKSR the scheme includes seven subdivisions of subregional extent: the Early Ginter (upper Albian), Grebenka (upper Albian-Cenomanian-lower Turonian), Penzhina (upper Turonian), Kaivayam (Coniacian), Barykov (Santonian-lower to ?middle Campanian), Gornorechenian (?upper Campanian-lower Maastrichtian), and Koryak (lower to upper Maastrichtian-?Danian) phytostratigraphic horizons. The phytostratigraphic scheme of the NASR includes three subregional phytostratigraphic horizons and five plant-bearing beds. These are the Kukpowruk (?lower to middle-?upper Albian), Niakogon (upper Albian-Cenomanian), Kaolak (Turonian) horizons and beds with the Tuluvak (Coniacian), Early Kogosukruk (upper Santonian-Campanian), Late Kogosukruk (Campanian-Maastrichtian), Early Sagwon (Danian-Selandian), and Late Sagwon (Selandian-Thanetian) floras. The comparative analysis of coeval (or close in age) floras distinguished in the AKSR and NASR shows that they are either similar to each other (floras Early Ginter and Kukpowruk, Grebenka and Niakogon, Penzhina and Kaolak, Koryak and Early Sagwon) or different in systematic composition (floras Kaivayam and Tuluvak, Gornorechenian and Kogosukruk). Similarities between the floras imply that plant assemblages of two subregions evolved under comparable climatic conditions and freely intercommunicated via the Bering Land Bridge during the Albian-Turonian and terminal Maastrichtian-Paleocene. Floras of the AKSR and NASR, which are of different composition, existed in particular intervals of geological history when trans-Beringian plant migrations were limited or even ceased because of palaeoclimatic difference between the

Impact of Northern Hemisphere polar gateways on the Arctic Ocean climate during the latest Cretaceous as simulated by an Earth System Model.

NASA Astrophysics Data System (ADS)

Niezgodzki, Igor; Knorr, Gregor; Lohmann, Gerrit; Tyszka, Jarosław

2017-04-01

Using the Earth System Model COSMOS, we simulate the Late Cretaceous climate with different gateway configurations in the Arctic Ocean region under constant CO2 level of 1120 ppm (4 x pre-industrial). Based on the Maastrichtian paleogeography, we modify gateway configurations in the Arctic region according to different scenarios recorded from the Campanian - Maastrichtian ( 83-66 Ma). Our simulation with the Greenland-Norwegian Sea even as deep as 1.5 km in the Campanian produces consistent salinities in the Greenland-Norwegian Sea and in the surface Arctic Ocean, with the proxy-based salinity reconstructions. Towards the end of the Maastrichtian the gateway became shallower but didn't close entirely before the K-Pg boundary. During entire interval, the simulated salinity in the Arctic Ocean was well stratified, in agreement with the data. The surface ocean became progressively fresher, starting from the moderately brackish conditions in the Campanian to the (almost) freshwater conditions around the K-Pg boundary. Arctic gateways configuration changes cannot reproduce cooling trends as reconstructed by the proxy data during the Campanian - Maastrichtian interval. Our additional sensitivity tests with the different CO2 levels (1-6 x pre-industrial) and fixed (Maastrichtian) paleogeography show that a doubling of atmospheric CO2 concentration from 560 ppm to 1120 ppm results in an increase in the zonal mean surface air temperature in the polar regions by as high as 10°C. This suggests that the CO2 level decline, rather than gateway configuration changes, was responsible for the cooling trend toward the end of the Maastrichtian. The research was supported from the grant of the National Science Center in Poland based on the decision DEC-2012/07/N/ST10/03419.

Integrated biostratigraphy and sealevel dynamics at the Santonian - early Campanian Schattau section - Northern Calcareous Alps, Austria

NASA Astrophysics Data System (ADS)

Wolfgring, Erik; Wagreich, Michael

2016-04-01

The Schattau section displays a Santonian to early Campanian transgressive sequence with a rich micro- and macro fossil fauna. A framework based on planktonic foraminifera, calcareous nannoplankton, ammonite, echinoid and crinoid biostratigraphy provides the foundation for a high resolution assessment of palaeoecologic changes in planktonic and benthic foraminiferal communities and local biostratigraphy (see Wagreich et al., 2009). The Santonian Hochmoos Formation (representing shallow water environments with the Sandkalkbank Member at the top of this unit) is overlain by the Santonian to Campanian Bibereck Formation (recording a distinct increase in water depth). The stratigraphically older subsections of the outcrop yield abundant miliolids and some rotaliid foraminiferal taxa (Quinqueloculina sp., Spiroloculina fassistomata, Hoeglundia spp., Gavellina spp.) and the larger benthic foraminifer Nummofallotia cretacea. A transgressive episode is recorded in the uppermost Hochmoos Formation's Sandkalkbank Member - consequently larger benthic foraminifera disappear and miliolids become a rare -, planktonic foraminifera an abundant element in deposits assigning to the stratigraphically youngest part of the Schattau section, the Bibereck Formation. Globotruncanids and marginotruncanids are frequently found. The planktonic/benthic foraminifera ratio rises from zero to ~50%. The benthic foraminiferal fauna is characterised by tubular and bi- and triserial agglutinated foraminifera (e.g. Ammobaculites spp., Dorothia spp., Gaudryina spp., Tritaxia spp.) as well as spiral calcareous benthic foraminifera (Gavellina spp., Lenticulina spp.). Accordingly, the younger deposits at the Schattau section record an outer neritic to upper slope environment. Planctonic foraminifera indicate the Dicarinella asymetrica and the lowest Globotruncanita elevata biozone: The top of the Schattau section records the last appearance of the planktonic foraminifera Dicarinella asymetrica and

Sedimentological evolution of the Cretaceous carbonate platform of Chiapas (Mexico)

NASA Astrophysics Data System (ADS)

Cros, Pierre; Michaud, François; Fourcade, Eric; Fleury, Jean-Jacques

1998-07-01

The Cretaceous epicontinental carbonate platform of Chiapas (south-east of Mexico) extends along a 200 km NW-SE narrow strip, north of the Sierra Madre basement, from Ocozocoautla to Comitan. In the western and central domain, three stratigraphic sections of the Sierra Madre Formation (late Aptian to early Senonian) display well exposed facies sequences enabling broad facies correlations about: (1) The successive transgressive-regressive stages, (2) the different subsidence rates controlling the outer to inner platform environmental evolution, (3) the conditions of tectonically controlled partial platform drowning during Campanian-Maastrichtian. Three other sections through the eastern Maastrichtian carbonate platform area record the changes from limestone to dolomite during the Angostura Maastrichtian platform stage. This evolution of thickness and facies in the occidental domain of Piedra Parada and in the central domain of Guadalupe Victoria and Julian Grajales illustrates the settlement process of the carbonate platform and the general decreasing of the thickness of the Sierra Madre Formation from west to east. The eastern platform domain (Comitan) crops out extensively and enables new correlations along a south-north transect. The Sierra Madre Formation and Angostura Formation documents continuous carbonate platform sedimentation with foraminifers, rudists and dasycladacean algae during Campanian and Maastrichtian. These sections permit palaeogeographical comparisons of depositional conditions of the Mexican margin of the Maya block.

Sedimentary provenance of Maastrichtian oil shales, Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Fathy, Douaa; Wagreich, Michael; Mohamed, Ramadan S.; Zaki, Rafat

2017-04-01

Maastrichtian oil shales are distributed within the Central Eastern Desert in Egypt. In this study elemental geochemical data have been applied to investigate the probable provenance of the sedimentary detrital material of the Maastrichtian oil shale beds within the Duwi and the Dakhla formations. The Maastrichtian oil shales are characterized by the enrichment in Ca, P, Mo, Ni, Zn, U, Cr and Sr versus post-Archean Australian shales (PAAS). The chondrite-normalized patterns of the Maastrichtian oil shale samples are showing LREE enrichment, HREE depletion, slightly negative Eu anomaly, no obvious Ce anomaly and typical shale-like PAAS-normalized patterns. The total REE well correlated with Si, Al, Fe, K and Ti, suggesting that the REE of the Maastrichtian oil shales are derived from terrigenous source. Chemical weathering indices such as Chemical Index of Alteration (CIA), Chemical Proxy of Alteration (CPA) and Plagioclase Index of Alteration (PIA) indicate moderate to strong chemical weathering. We suggest that the Maastrichtian oil shale is mainly derived from first cycle rocks especially intermediate rocks without any significant inputs from recycled or mature sources. The proposed data illustrated the impact of the parent material composition on evolution of oil shale chemistry. Furthermore, the paleo-tectonic setting of the detrital source rocks for the Maastrichtian oil shale is probably related to Proterozoic continental island arcs

Vertebrate paleontological exploration of the Upper Cretaceous succession in the Dakhla and Kharga Oases, Western Desert, Egypt

NASA Astrophysics Data System (ADS)

Sallam, Hesham M.; O'Connor, Patrick M.; Kora, Mahmoud; Sertich, Joseph J. W.; Seiffert, Erik R.; Faris, Mahmoud; Ouda, Khaled; El-Dawoudi, Iman; Saber, Sara; El-Sayed, Sanaa

2016-05-01

The Campanian and Maastrichtian stages are very poorly documented time intervals in Africa's record of terrestrial vertebrate evolution. Upper Cretaceous deposits exposed in southern Egypt, near the Dakhla and Kharga Oases in the Western Desert, preserve abundant vertebrate fossils in nearshore marine environments, but have not yet been the focus of intensive collection and description. Our recent paleontological work in these areas has resulted in the discovery of numerous new vertebrate fossil-bearing localities within the middle Campanian Qusier Formation and the upper Campanian-lower Maastrichtian Duwi Formation. Fossil remains recovered from the Campanian-aged Quseir Formation include sharks, rays, actinopterygian and sarcopterygian fishes, turtles, and rare terrestrial archosaurians, including some of the only dinosaurs known from this interval on continental Africa. The upper Campanian/lower Maastrichtian Duwi Formation preserves sharks, sawfish, actinopterygians, and marine reptiles (mosasaurs and plesiosaurs). Notably absent from these collections are representatives of Mammalia and Avialae, both of which remain effectively undocumented in the Upper Cretaceous rocks of Africa and Arabia. New age constraints on the examined rock units is provided by 23 nannofossil taxa, some of which are reported from the Duwi Formation for the first time. Fossil discoveries from rock units of this age are essential for characterizing the degree of endemism that may have developed as the continent became increasingly tectonically isolated from the rest of Gondwana, not to mention for fully evaluating origin and diversification hypotheses of major modern groups of vertebrates (e.g., crown birds, placental mammals).

Dinoflagellate cyst biostratigraphy of the Upper Cretaceous succession in the sub-Arctic region

NASA Astrophysics Data System (ADS)

Radmacher, Wiesława; Tyszka, Jarosław; Mangerud, Gunn; Pearce, Martin

2017-04-01

The study provides a solid basis for the first palynostratigraphic zonation of the Upper Cretaceous sub-Arctic succession. Dinoflagellate cysts from the unique composite section, combining samples from the shallow stratigraphic core 6711/4-U-1 and core-samples from well 6707/10-1 in the Norwegian Sea, were studied and compared to palynological data from the south-western Barents Sea, wells 7119/12-1, 7119/9-1, 7120/7-3, 7120/5-1 and 7121/5-1. Dinoflagellate cysts diagnostic for late Maastrichtian that are missing in the Barents Sea are recorded in both sections in the Norwegian Sea. This adds new valuable data from the time interval often represented by a significant regional hiatus in the area. Seven new and three previously recognised zones are identified, based on top and base occurrence of selected age diagnostic taxa. In addition, one Abundance Subzone is introduced. The biostratigraphic zonation includes: the intra late Albian to intra early Cenomanian Subtilisphaera kalaalliti Interval Zone sensu Nøhr-Hansen (1993); the intra early Cenomanian to intra late Cenomanian Palaeohystrichophora infusorioides-Palaeohystrichophora palaeoinfusa Interval Zone sensu Radmacher et al. (2014); the intra Turonian to ?intra early Coniacian Heterosphaeridium difficile Interval Zone sensu Nøhr-Hansen (2012); the ?intra early Coniacian to late Santonian Dinopterygium alatum Interval Zone sensu Radmacher et al. (2014); the ?early Campanian Palaeoglenodinium cretaceum Interval Zone sensu Radmacher et al. (2014); the intra Campanian Hystrichosphaeridium dowlingii-Heterosphaeridium spp. Interval Zone sensu Radmacher et al. (2015); the intra late Campanian Chatangiella bondarenkoi Interval Zone sensu Radmacher et al. (2014) encompassing the Heterosphaeridium bellii Abundance Subzone; the early Maastrichtian Cerodinium diebelii Interval Zone sensu Nøhr-Hansen (1996) and the intra late Maastrichtian Wodehouseia spinata Range Zone sensu Nøhr-Hansen (1996). The Heterosphaeridium

The genus Krithe (Ostracoda) from the Campanian and Maastrichtian (Upper Cretaceous) of the northern US Gulf Coastal Plain

USGS Publications Warehouse

Puckett, T.M.

1997-01-01

The ostracode genus Krithe is one of the most common genera in the Upper Cretaceous (late Santonian to Maastrichtian) deposits of the northern Gulf Coastal Plain of North America. Although it is never abundant, the genus occurs in sediments that were deposited under a wide range of palaeoenvironments, including nearshore sandy marls to offshore, nearly pure, chalk. The taxonomy of this taxon has been problematical, and what is herein considered to be a single species, K. cushmani, has been referred to in the literature under five different names. Two morphotypes were observed: relatively large individuals with 'mushroom'-shaped vestibules collected from chalk, and smaller individuals with pocket-shaped vestibules collected from nearshore deposits. Species of Krithe have been hypothesized to be useful in estimating dissolved oxygen concentration in ancient ocean floors, based on details of their morphology. Whereas the relationship between size and environment corroborates with previous predictions (larger individuals live in deeper water), the morphology of the vestibules contradicts predictions (the larger vestibules occur in the nearshore deposits and the smaller, more constricted vestibules occur in the chalk). A causal relationship between environment and morphology is discussed.

Revised nomenclature, definitions, and correlations for the Cretaceous formations in USGS-Clubhouse Crossroads #1, Dorchester County, South Carolina

USGS Publications Warehouse

Gohn, Gregory S.

1992-01-01

and definitions of the Cape Fear, Middendorf, Black Creek, and Peedee Formations originally used for the core by Gohn and others and Hazel and others are substantially changed herein. In addition, the Black Creek Formation of the core is raised in rank to become the Black Creek Group, which consists of two newly defined formations (Cane Acre and Coachman) and two newly recognized formations previously described in outcrop (Bladen and Donoho Creek). Four subsurface formations that are not known in outcrop are newly defined in the core (Beech Hill, Clubhouse, Shepherd Grove, and Caddin). The revised stratigraphy of the Cretaceous section in the Clubhouse Crossroads #1 core, from base to top, is as follows: Beech Hill Formation (Cenomanian?), Clubhouse Formation (late Cenomanian? and Turonian), Cape Fear Formation (late Turonian? to early Santonian), Middendorf Formation (middle Santonian), Shepherd Grove Formation (late Santonian and early Campanian), Caddin Formation (early Campanian), Cane Acre Formation (middle Campanian, Black Creek Group), Coachman Formation (middle to late Campanian, Black Creek Group), Bladen Formation (late Campanian, Black Creek Group), Donoho Creek Formation (early Maastrichtian, Black Creek Group), and Peedee Formation (late early Maastrichtian to middle or late Maastrichtian).

New constraints on the pyroclastic eruptive history of the Campanian volcanic Plain (Italy)

USGS Publications Warehouse

de Vivo, B.; Rolandi, G.; Gans, P.B.; Calvert, A.; Bohrson, W.A.; Spera, F.J.; Belkin, H.E.

2001-01-01

The ∼ 150 km3 (DRE) trachytic Campanian Ignimbrite, which is situated north-west of Naples, Italy, is one of the largest eruptions in the Mediterranean region in the last 200 ky. Despite centuries of investigation, the age and eruptive history of the Campanian Ignimbrite is still debated, as is the chronology of other significant volcanic events of the Campanian Plain within the last 200–300 ky. New 40Ar/39Ar geochronology defines the age of the Campanian Ignimbrite at 39.28 ± 0.11 ka, about 2 ky older than the previous best estimate. Based on the distribution of the Campanian Ignimbrite and associated uppermost proximal lithic and polyclastic breccias, we suggest that the Campanian Ignimbrite magma was emitted from fissures activated along neotectonic Apennine faults rather than from ring fractures defining a Campi Flegrei caldera. Significantly, new volcanological, geochronological, and geochemical data distinguish previously unrecognized ignimbrite deposits in the Campanian Plain, accurately dated between 157 and 205 ka. These ages, coupled with a xenocrystic sanidine component > 315 ka, extend the volcanic history of this region by over 200 ky. Recent work also identifies a pyroclastic deposit, dated at 18.0 ka, outside of the topographic Campi Flegrei basin, expanding the spatial distribution of post-Campanian Ignimbrite deposits. These new discoveries emphasize the importance of continued investigation of the ages, distribution, volumes, and eruption dynamics of volcanic events associated with the Campanian Plain. Such information is critical for accurate assessment of the volcanic hazards associated with potentially large-volume explosive eruptions in close proximity to the densely populated Neapolitan region.

Latest Cretaceous-Paleogene basin development and resultant sedimentation patterns in the thrust belt and broken foreland of central Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawton, T.F.; Franczyk, K.J.; Pitman, J.K.

1990-05-01

Latest Cretaceous tectonism in central and east-central Utah formed several intermontane basins both atop thrust sheets and between the thrust front and basement-involved uplifts in the former foreland basin. The upper Campanian Castlegate Sandstone and its inferred western equivalents were the last strata deposited prior to segmentation of the foreland basin. Thereafter, eastward transport of the thrust allochthon uplifted the most proximal part of the Castlegate depositional wedge. West of the thrust front, small intermontane basins formed on the allochthon. Sediment was transported into these basins from both eastern and western sources. In each basin, facies grade from basin-margin conglomeraticmore » alluvial fan deposits to basin-interior flood-plain and lacustrine deposits within a few kilometers. These intermontane basins existed from latest Campanian through the late Paleocene, and may have been transported a short distance eastward as they formed. East of the thrust front in the latest Campanian and contemporaneous with basin formation on the allochthon, a northward-northeastward-flowing big river system transported sediment into the foreland basin from feldspar-rich source areas southwest of the study area. Subsequently, major movement of the San Rafael uplift in the very late Campanian or early Maastrichtian gave rise to an intermontane basin between the thrust front and the San Rafael uplift. Northwestward-flowing, pebble-bearing braided rivers deposited the oldest sediments in this basin prior to an influx from the south and southwest of sediment that formed a thick Maastrichtian clastic sequence. In contrast to deposition in basins on the allochthon, deposition east of the thrust front in the Paleocene was intermittent and restricted to rapidly shifting centers of basin subsidence.« less

The base of the Campanian: a magnetostratigraphic definition, integrated biostratigraphy and isotope stratigraphy

NASA Astrophysics Data System (ADS)

Wagreich, Michael; Dinarès-Turell, Jaume; Wolfgring, Erik; Omer Yilmaz, Ismail

2017-04-01

for the base of the Campanian. Strontium isotope stratigraphy indicates a value of 0.707534. Both carbon and oxygen isotope values show a negative excursion just below the boundary. The positive Santonian-Campanian boundary carbon isotope event (SCBE) starts probably just at the boundary level. This interval is considered to correspond to a short sea-level high in the late Santonian followed by a lowstand at the Santonian-Campanian boundary. Macrofossil data from the nearby Schattau section indicate the late Santonian Paraplanum ammonite Subzone, the presence of the crinoid Marsupites laevigatus and inoceramids, e.g. Cordiceramus muelleri muelleri, below the boundary as defined by magnetostratigraphy. Sections from the western Tethyan Mudurnu-Göynük basin (NW Turkey) provide similar evidence for the Santonian-Campanian boundary interval. Near Göynük town, a reversal of the magnetic polarity was identified to represent the base of C33r within a pelagic section. Biostratigraphic data suggest an age from the late Santonian Dicarinella asymetrica to the early Campanian Globotruncanita elevata planktonic foraminifera zone, and nannofossil zones UC13-CC14. Results from the assessment of field magnetic susceptibility give evidence for Milankovitch cycles, presumably the 405 ka eccentricity cycle.

Abrupt Climatic Change during the Latest Maastrichtian: Establishing Robust Temporal Links with the Onset of Deccan Volcanism and K/Pg Mass Extinction

NASA Astrophysics Data System (ADS)

Barnet, J.; Littler, K.; Kroon, D.; Leng, M. J.; Westerhold, T.; Roehl, U.; Zachos, J. C.

2017-12-01

A transient period of climate change, characterized by a global warming of 2.5-5°C followed by a cooling to pre-excursion conditions, occurred during the last 300 kyr of the Maastrichtian ( 66.34-66.02 Ma). This instability may have played a role in destabilizing marine and terrestrial ecosystems, priming the system for abrupt extinction at the K-Pg boundary, likely triggered by a large bolide impact. This pre-K-Pg warming event has often been linked to the main phase of Deccan Trap volcanism, however large uncertainties associated with radio-isotopic dating methods of basalts, along with low sedimentation rates and hiatuses in many studied sedimentary sequences, have long hampered a definitive correlation. To complement recent advances in dating of the traps, we have generated the first complete and highest resolution (2.5-4 kyr) benthic stable δ13C and δ18O record for the final million years of the Maastrichtian using the epifaunal foraminifera species Nuttallides truempyi from ODP Site 1262, Walvis Ridge, South Atlantic, calibrated to an updated orbitally-tuned age model. We then compare our data to other previously published geochemical data from other sites in the high, middle, and low latitudes. Our data confirms that the onset of the warming event coincides with the onset of the main phase of Deccan volcanism, strongly suggesting a causal link. Furthermore, spectral analysis of our extended late Maastrichtian-Early Eocene record suggests that the onset of the warming event corresponds to a 405-kyr eccentricity minima, in contrast to many transient warming events (hyperthermals) of the Paleogene, suggesting a control by orbital forcing alone is unlikely. A peculiar feature of the event, compared to other hyperthermals, is a muted carbon cycle response during warming, which may be related to the comparatively heavier δ13C signature of volcanogenic CO2 (-7‰), compared to other sources of light carbon invoked to explain Paleogene hyperthermals. The warming

Stratigraphy, sedimentology and tectonic evolution of the Upper Cretaceous/Paleogene succession in north Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

El Ayyat, Abdalla M.; Obaidalla, Nageh A.

2013-05-01

, fine-grained limestones and fine siliciclastic shales (Sudr, Dakhla, Tarawan and Esna formations). The northeastern parts are marked by little contents of planktonic foraminifera and dolomitized, slumped carbonates, intercalated with basinal facies. Tectonically, four remarkable syn-depositional tectonic events (SdTEs) controlled the evolution of the studied succession. These events took place strongly within the Campanian-Ypresian time interval and were still active till Late Eocene. These events took place at: the Santonian/Campanian (S/C) boundary; the Campanian/Maastrichtian (C/M) boundary; the Cretaceous/Paleogene (K/P) boundary; and the Middle Paleocene-Early Eocene interval. These tectonic events are four pronounced phases in the tectonic history of the Syrian Arc System (SAS), the collision of the Afro-Arabian and Eurasian plates as well as the closure of the Tethys Sea.

Uplift of continental crustal blocks adjacent to the Rancheria Basin-Guasare area: the effects of Maastrichtian-Paleocene collision along the southern Caribbean plate boundary

NASA Astrophysics Data System (ADS)

Bayona, G.; Montes, C.; Jaramillo, C.; Ojeda, G.; Cardona, A.; Pardo, A.; Lamus, F.

2007-05-01

In the Rancheria basin (RB) and Guasare area (GA), Maastrichtian-Paleocene synorogenic strata overlie the Aptian-Campanian carbonate platform. Nowadays, RB is bounded to the west by metamorphic-and-igneous cored Santa Marta massif, where Upper Cretaceous strata overlie unconformably pre-Cretaceous rocks. The eastern boundary of the RB is the Perija range that includes volcaniclastic and sedimentary rocks of Jurassic and Cretaceous age in the hanging-wall of a NW-verging, low-angle dipping thrust belt. The GA is on the eastern foothills of the Perija range and corresponds to the western boundary of the Maracaibo basin. Strata architecture, seismic reflectors, gravity, provenance, and paleocurrent analyses carried out in those basins constrain the timing and style of uplift of Santa Marta massif and Perija range, which are linked with tectonism along the southern Caribbean plate. Maastrichtian-Paleocene strata thicken eastward up to 2.2 km in the RB, and this succession includes (in stratigraphic order): foram-rich calcareous mudstone, oyster-pelecypod rich carbonate-siliciclastic strata, coal- bearing mudstones and feldspar-lithic-rich fluvial sandstones. Internal disconformities and truncations of seismic reflectors are identified to the west of the RB, but there are not major thrust faults at this part of the basin to explain such unconformities and truncations. In Early Paleocene, carbonates developed better to the west of the RB, whereas mixed carbonate-siliciclastic deposition continued toward the east of the RB. In early Late Paleocene, influx of terrigenous material (key grains=metamorphic, microcline and garnet fragments) derived from the Santa Marta massif increased to the west, but to the east of the RB and GA carbonate-siliciclastic and carbonate deposition continued, respectively. In mid-Late Paleocene, diachronous eastward advance of paralic/deltaic environments, tropical humid climate, and high subsidence rates favored production and preservation of

Radiolarians, foraminifers, and biostratigraphy of the Coniacian-Campanian deposits of the Alan-Kyr Section, Crimean Mountains

NASA Astrophysics Data System (ADS)

Bragina, L. G.; Beniamovsky, V. N.; Kopaevich, L. F.

2016-01-01

Data on the distribution of radiolarians and planktonic and benthic foraminifers are obtained for the first time from the Alan-Kyr Section (Coniacian-Campanian), in the central regions of the Crimean Mountains. Radiolarian biostrata, previously established from Ak-Kaya Mountain (central regions of the Crimean Mountains) were traced: Alievium praegallowayi-Crucella plana (upper Coniacian-lower Santonian), Alievium gallowayi-Crucella espartoensis (upper Santonian without the topmost part), and Dictyocephalus (Dictyocryphalus) (?) legumen-Spongosaturninus parvulus (upper part of the upper Santonian). Radiolarians from the Santonian-Campanian boundary beds of the Crimean Mountains are studied for the first time, and Prunobrachium sp. ex gr. crassum-Diacanthocapsa acanthica Beds (uppermost Santonian-lower Campanian) are recognized. Bolivinoides strigillatus Beds (upper Santonian) and Stensioeina pommerana-Anomalinoides (?) insignis Beds (upper part of the upper Santonian-lower part of the lower Campanian) are recognized. Eouvigerina aspera denticulocarinata Beds (middle and upper parts of the lower Campanian) and Angulogavelinella gracilis Beds (upper part of the upper Campanian are recognized on the basis of benthic foraminifers. These beds correspond to the synchronous biostrata of the East European Platform and Mangyshlak. Marginotruncana coronata- Concavatotruncana concavata Beds (Coniacian-upper Santonian), Globotruncanita elevata Beds (terminal Santonian), and Globotruncana arca Beds (lower Campanian) are recognized on the basis of planktonic foraminifers. Radiolarian and planktonic and benthic foraminiferal data agree with one another. The position of the Santonian-Campanian boundary in the Alan-Kyr Section, which is located stratigraphically above the levels of the latest occurrence of Concavatotruncana concavata and representatives of the genus Marginotruncana, is refined, i.e., at the level of the first appearance of Globotruncana arca. A gap in the Middle

The chronostratigraphic framework of the South-Pyrenean Maastrichtian succession reappraised: Implications for basin development and end-Cretaceous dinosaur faunal turnover

NASA Astrophysics Data System (ADS)

Fondevilla, Víctor; Dinarès-Turell, Jaume; Oms, Oriol

2016-05-01

The evolution of the end-Cretaceous terrestrial ecosystems and faunas outside of North America is largely restricted to the European Archipelago. The information scattered in this last area can only be integrated in a chronostratigraphic framework on the basis of robust age constraints and stratigraphy. Therefore, we have revisited the puzzling age calibration of the sedimentary infilling from the Isona sector in the Tremp syncline (South-Central Pyrenees), an area renowned for its rich Maastrichtian dinosaur fossil record. Aiming to shed light to existing controversial age determinations, we carried out a new magnetostratigraphic study along the ~ 420 m long Orcau and Nerets sections of that area. Our results reveal that most of the succession correlates to the early Maastrichtian (mostly chron C31r) in accordance to ages proposed by recent planktonic foraminifera biostratigraphy. The resulting chronostratigraphic framework of the entire Maastrichtian basin recorded in the Tremp syncline shows that a significant sedimentary hiatus of about 3 My characterizes most of the late Maastrichtian in the study area. This hiatus, related to an abrupt migration of the basin depocenter, is temporally close to similar hiatuses, decreases in sedimentary rates and facies shifts recorded in other southwestern European areas. The present chronologic framework sets the basis for a thorough assessment of end-Cretaceous terrestrial faunal turnover and extinction patterns, and the establishment of a more rigorous Pyrenean basin evolution analysis.

Late Cretaceous - Paleogene forearc sedimentation and accretion of oceanic plateaus and seamounts along the Middle American convergent margin (Costa Rica)

NASA Astrophysics Data System (ADS)

Baumgartner, Peter O.; Baumgartner-Mora, Claudia; Andjic, Goran

2016-04-01

The Late Cretaceous-Paleogene sedimentation pattern in space and time along the Middle American convergent margin was controlled by the accretion of Pacific plateaus and seamounts. The accretion of more voluminous plateaus must have caused the temporary extinction of the arc and tectonic uplift, resulting in short lived episodes of both pelagic and neritic biogenic sedimentation. By the Late Eocene, shallow carbonate environments became widespread on a supposed mature arc edifice, that is so far only documented in arc-derived sediments. In northern Costa Rica forearc sedimentation started during the Coniacian-Santonian on the Aptian-Turonian basement of the Manzanillo Terrane. The arrival and collision of the Nicoya Terrane (a CLIP-like, 139-83 Ma Pacific plateau) and the Santa Elena Terrane caused the extinction of the arc during late Campanian- Early Maastrichtian times, indicated by the change to pelagic limestone sedimentation (Piedras Blancas Formation) in deeper areas and shallow-water rudistid - Larger Benthic Foraminfera limestone on tectonically uplifted areas of all terranes. Arc-derived turbidite sedimentation resumed in the Late Maastrichtian and was again interrupted during the Late Paleocene - Early Eocene, perhaps due to the underplating of a yet unknown large seamount. The extinction of the arc resulted in the deposition of the siliceous pelagic Buenavista Formation, as well as the principally Thanetian Barra Honda carbonate platform on a deeply eroded structural high in the Tempisque area. In southern Costa Rica the basement is thought to be the western edge of the CLIP. It is Santonian-Campanian in age and is only exposed in the southwestern corner of Herradura. Cretaceous arc-forearc sequences are unknown, except for the Maastrichtian-Paleocene Golfito Terrane in southeastern Costa Rica. The distribution and age of shallow/pelagic carbonates vs. arc-derived detrital sediments is controlled by the history of accretion of Galápagos hot spot

A new horned dinosaur reveals convergent evolution in cranial ornamentation in Ceratopsidae.

PubMed

Brown, Caleb M; Henderson, Donald M

2015-06-15

Ceratopsid (horned) dinosaurs are an iconic group of large-bodied, quadrupedal, herbivorous dinosaurs that evolved in the Late Cretaceous and were largely restricted to western North America [1-5]. Ceratopsids are easily recognized by their cranial ornamentation in the form of nasal and postorbital horns and frill (capped by epiossifications); these structures show high morphological disparity and also represent the largest cranial display structures known to have evolved [2, 4]. Despite their restricted occurrence in time and space, this group has one of the best fossil records within Dinosauria, showing a rapid diversification in horn and frill morphology [1]. Here a new genus and species of chasmosaurine ceratopsid is described based on a nearly complete and three-dimensionally preserved cranium recovered from the uppermost St. Mary River Formation (Maastrichtian) of southwestern Alberta. Regaliceratops peterhewsi gen. et sp. nov. exhibits many unique characters of the frill and is characterized by a large nasal horncore, small postorbital horncores, and massive parietal epiossifications. Cranial morphology, particularly the epiossifications, suggests close affinity with the late Campanian/early Maastrichian taxon Anchiceratops, as well as with the late Maastrichtian taxon Triceratops. A median epiparietal necessitates a reassessment of epiossification homology and results in a more resolved phylogeny. Most surprisingly, Regaliceratops exhibits a suite of cranial ornamentations that are superficially similar to Campanian centrosaurines, indicating both exploration of novel display morphospace in Chasmosaurinae, especially Maastrichtian forms, and convergent evolution in horn morphology with the recently extinct Centrosaurinae. This marks the first time that evolutionary convergence in horn-like display structures has been demonstrated between dinosaur clades, similar to those seen in fossil and extant mammals [6]. Copyright © 2015 Elsevier Ltd. All rights

Cyclostratigraphy and orbital tuning of the terrestrial upper Santonian-Lower Danian in Songliao Basin, northeastern China

NASA Astrophysics Data System (ADS)

Wu, Huaichun; Zhang, Shihong; Hinnov, Linda A.; Jiang, Ganqing; Yang, Tianshui; Li, Haiyan; Wan, Xiaoqiao; Wang, Chengshan

2014-12-01

The Songke-1 north (SK-1n) borehole recovered a continuous, 1541.66 m Late Santonian-Early Danian terrestrial succession in Songliao Basin (SB), northeastern China. It provides a unique record for improving our understanding of continental paleoclimate and ecological system in Cretaceous greenhouse world. Here we use thorium (Th) logging data as a paleoenvironmental and paleoclimatic proxy to conduct a detailed cyclostratigraphic study on the SK-1n core. Power spectra, evolutionary fast Fourier transformation and wavelet analysis all reveal significant decameter- to meter-scale sedimentary cycles in the Nenjiang (K2n), Sifangtai (K2s) and Mingshui (K2m) formations. The ratios of cycle wavelengths in these stratigraphic units are ∼20:5:2:1, and are interpreted as Milankovitch cycles of 405 kyr and 100 kyr eccentricity, 38.4 kyr obliquity and 20 kyr precession cycles, respectively. An astronomical time scale (ATS) is established by tuning filtered 405 kyr eccentricity cycles to a target curve of the astronomical solution La2010d based on the magnetostratigraphic time framework of the SK-1n borehole. This ATS provides precise numerical ages for stratigraphic boundaries, biozones, geological and geophysical events, and serves as a basis for correlation of strata and events between marine and terrestrial systems. The Cretaceous/Paleogene (K/Pg), Campanian/Maastrichtian, Santonian/Campanian boundaries are estimated at core depths of 318 m, 752.8 m and 1751.1 m, respectively. A ∼3.8 myr-long hiatus between the Nenjiang (K2n) and Sifangtai (K2s) formations occurs from 76.1 to 79.9 million years ago. The ages and durations of magnetochrons C33r to C30n are precisely estimated and provide new constraints on the Late Cretaceous Geomagnetic Polarity Time Scale (GPTS) and South Atlantic sea-floor spreading rates.

Climate change and carbon-cycling during the latest Cretaceous-Early Paleogene; a new 13.5 million year-long, orbital-resolution, stable isotope record from the South Atlantic

NASA Astrophysics Data System (ADS)

Barnet, J.; Littler, K.; Kroon, D.; Leng, M. J.; Westerhold, T.; Roehl, U.; Zachos, J. C.

2017-12-01

The "greenhouse" world of the latest Cretaceous-Early Paleogene ( 70-34 Ma) was characterised by multi-million year variability in climate and the carbon-cycle. Throughout this interval the pervasive imprint of orbital-cyclicity, particularly eccentricity and precession, is visible in elemental and stable isotope data obtained from multiple deep-sea sites. Periodic "hyperthermal" events, occurring largely in-step with these orbital cycles, have proved particularly enigmatic, and may be the closest, albeit imperfect, analogues for anthropogenic climate change. This project utilises CaCO3-rich marine sediments recovered from ODP Site 1262 at a paleo-depth of 3600 m on the Walvis Ridge, South Atlantic, of late Maastrichtian-mid Paleocene age ( 67-60 Ma). We have derived high-resolution (2.5-4 kyr) carbon and oxygen isotope data from the epifaunal benthic foraminifera species Nuttallides truempyi. Combining the new record with the existing Late Paleocene-Early Eocene record generated from the same site by Littler et al. (2014), yields a single-site reference curve detailing 13.5 million years of orbital cyclicity in paleoclimate and carbon cycle from the latest Cretaceous to near the peak warmth of the Early Paleogene greenhouse. Spectral analysis of this new combined dataset allows us to identify long (405-kyr) eccentricity, short (100-kyr) eccentricity, and precession (19-23-kyr) as the principle forcing mechanisms governing pacing of the background climate and carbon-cycle during this time period, with a comparatively weak obliquity (41-kyr) signal. Cross-spectral analysis suggests that changes in climate lead the carbon cycle throughout most of the record, emphasising the role of the release of temperature-sensitive carbon stores as a positive feedback to an initial warming induced by changes in orbital configuration. The expression of comparatively understudied Early Paleocene events, including the Dan-C2 Event, Latest Danian Event, and Danian/Selandian Transition

A transgressive Santonian-Campanian boundary sequence revisited - High resolution planktonic and benthic foraminifera stratigraphy of the Schattau section, Northern Calcareous Alps.

NASA Astrophysics Data System (ADS)

Wolfgring, Erik; Wagreich, Michael; Summesberger, Herbert; Kroh, Andreas

2016-04-01

The Schattau section is part of the Austrian Gosau Group, Northern Calcareous Alps. We record a Santonian to early Campanian transgressive sequence. Previous investigations already provide a biostratigraphic framework; a multidisciplinary study to reveal the local stratigraphy and palaeoenvironmental properties: Planktonic foraminifera, calcareous nannoplankton, ammonite, echinoid and crinoid biostratigraphy data suggest a Santonian to earliest Campanian age for this section (see Wagreich et al., 2009). This work aims at a high resolution assessment of foraminiferal assemblages recorded from a time interval that has undergone significant palaeoenvironmental changes. The Santonian Hochmoos Formation, with the Sandkalkbank Member representing it's topmost subunit, is overlain by the Santonian to Campanian Bibereck Formation. While The Hochmoos Formation records a shallowing succession that finds the Sandkalkbank Member (representing very shallow conditions, sometimes sub aerial exposure) at its top. The overlying Bibereck Formation records a distinct deepening trend displaying increasingly marine, neritic to outer neritic conditions. The stratigraphically older subunits of the Schattau sections are characterised by abundant larger benthic foraminifera (Nummofallotia cretacea), miliolid foraminifera (Quinqueloculina spp, Spiroloculina fassistomata) as well as rotaliid foraminifera (Hoeglundia spp., Gavellina spp.). The Sandkalkbank member marks the end of the shallow water sequence recorded from foraminifera assemblages at the Schattau section. Up section communities are characterised by increasing share of planktonic foraminifera. Biostratigraphic marker fossils like Dicarinella asymetrica and Sigalia sp. (decoratissima?) were identified and indicate a Santonian age for the Bibereck Formation. The appearance of Globotruncanita elevata and disappearance of D. asymetrica and Sigalia sp. Suggests an early Campanian age for the topmost part of the Schattau section

Calcareous nannofossil evidence for the existence of the Gulf Stream during the late Maastrichtian

USGS Publications Warehouse

Watkins, D.K.; ,

2005-01-01

Upper Maastrichtian calcareous nannofossil assemblages, from eight cores on the South Carolina Coastal Plain (onshore set) and three deep sea drilling sites from the continental slope and abyssal hills (offshore set), were analyzed by correlation and principal component analysis to examine the ancient surface water thermal structure. In addition, a temperature index derived from independently published paleobiogeographic information was applied to the sample data. All three methods indicate a strong separation of the samples into onshore and offshore sets, with the offshore data set exhibiting significantly warmer paleotemperatures. The great disparity between these two sample sets indicates that there was a strong thermal contrast between the onshore and offshore surface water masses that persisted throughout the late Maastrichtian despite evident shortterm changes in fertility, productivity, and community structure. This suggests the Gulf Stream was present as a major oceanographic feature during the late Maastrichtian. Copyright 2005 by the American Geophysical Union.

Campanian ammonites from the Upper Cretaceous Gober Chalk of Lamar County, Texas

USGS Publications Warehouse

Cobban, W.A.; Kennedy, W.J.

1992-01-01

The Roxton Limestone Member at the top of the Gober Chalk in northeast Texas yields a rich fauna, dominated by Baculites haresi Reeside, 1927, and Inoceramus balticus Boehm, 1909, with sparse occurrences of pachydiscus cf. P. paulsoni (Young, 1963), Anapachydiscus sp.juv., Placenticeras placenta (DeKay, 1828), Hoplitoplacenticeras aff. H. plasticum (Paulcke, 1907), Menabites (Delawarella) delawarensis (Morton, 1830), M.(D.) danei (Young, 1963), M.(D.) aff. M.(D.) vanuxemi (Morton, 1830), Submortoniceras vandalinaense Young, 1963, Submortoniceras sp., Eubostrychoceras sp., and Scaphites hippocrepis (DeKay, 1828) III. The presence of S. hippocrepis III suggests a late early Campanian age assignment for the fauna. The assemblage includes species known from the Western Interior, Gulf Coast, Atlantic seaboard, and western Europe. -Authors

Petrology and tectonic history of the Green Bay Schist, Portmore, St. Catherine Parish, Jamaica

USGS Publications Warehouse

Abbott, Richard N.; West, David P.; Bandy, Betsy R.; McAleer, Ryan J.

2016-01-01

There are three occurrences of medium- to high-grade metamorphic rocks in Jamaica: amphibolite facies Westphalia Schist, blueschist/greenschist facies Mt. Hibernia Schist, and the hitherto poorly characterized amphibolite facies Green Bay Schist. New trace element data and thermodynamic calculations show that Green Bay Schist is closely related to Westphalia Schist. The protoliths for both are very similiar (basalt-andesitic basalt, C-MORB), consistent with a subducted ocean-ridge tectonic environment, hence arc-related. The protolith for Mt. Hibernia Schist is quite different (basalt, P-MORB), related to the Caribbean Large Igneous Province. Whereas the P-T-t paths for Green Bay Schist and Westphalia Schist prior to the middle Campanian (>78 Ma) are inferred to be similar, the late Campanian, Maastrichtian and Cenozoic P-T-t paths are very different. New 40Ar/39Ar age determinations show the following: (1) While the difference in the late Campanian and Maastrichtian remains problematic, (2) the difference in the Cenozoic clearly reflects the location relative to the NW-trending, NE-dipping Wagwater Fault: Westphalia Schist to the NE (hanging wall); Green Bay Schist to the SW (foot wall). The Cenozoic P-T-t paths are complementary, and consistent with the behavior of the Wagwater Fault: 65-50 Ma, normal motion (transtension); 50-10 Ma, inactive (quiescent); 10 Ma-present, reverse motion (transpression).

Relative sea level changes during the Cretaceous in Israel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flexer, A.; Rosenfeld, A.; Lipson-Benitah, S.

1986-11-01

Detailed lithologic, microfaunal, and biometric investigations, using relative abundances, diversity indexes, and duration charts of ostracods and foraminifera, allowed the recognition of sea level changes during the Cretaceous of Israel. Three major transgressive-regressive sedimentation cycles occur on the northwest margins of the Arabian craton. These cycles are the Neocomian-Aptian, which is mostly terrigenous sediments; the Albian-Turonian, which is basin marls and platform carbonates; and the Senonian, which is uniform marly chalks. The cycles are separated by two major regional unconformities, the Aptian-Albian and Turonian-Coniacian boundaries. The sedimentary cycles are related to regional tectonic and volcanic events and eustatic changes. Themore » paleodepth curve illustrates the gradual sea level rise, reaching its maximum during the Late Cretaceous, with conspicuous advances during the late Aptian, late Albian-Cenomanian, early Turonian, early Santonian, and early Campanian. Major lowstands occur at the Aptian-Albian, Cenomanian-Turonian, Turonian-Coniacian, and Campanian-Maastrichtian boundaries. This model for Israel agrees well with other regional and global sea level fluctuations. Four anoxic events (black shales) accompanying transgressions correspond to the Cretaceous oceanic record. They hypothesize the presence of mature oil shales in the present-day eastern Mediterranean basin close to allochthonous reef blocks detached from the Cretaceous platform. 11 figures.« less

Paleocene and Maastrichtian calcareous nannofossils from clasts in Pleistocene glaciomarine muds from the northern James Ross Basin, western Weddell Sea, Antarctica

USGS Publications Warehouse

Kulhanek, D.K.

2007-01-01

Site NBP0602A-9, drilled during the SHALDRIL II cruise of the RV/IB Nathaniel B. Palmer, includes two holes located in the northern James Ross Basin in the western Weddell Sea, very close to the eastern margin of the Antarctic Peninsula. Sediment from both holes consists of very dark grey, pebbly, sandy mud, grading to very dark greenish grey, pebbly, silty mud in the lower 2.5 m of the second hole. In addition to abundant pebbles found throughout the cores, both holes contain numerous sedimentary clasts. Biostratigraphic analysis of diatom assemblages from the glaciomarine muds yields rare to few, poorly preserved diatoms. The mixed assemblage consists mostly of extant species, but also includes reworked taxa that range to the Miocene. The absence of Rouxia spp., however, suggests the sediment is late Pleistocene in age. The sedimentary clasts, on the other hand, are nearly barren of diatoms, but contain rare, moderately to well-preserved calcareous nannofossils. The clasts contain three distinct assemblages. Two clasts are assigned an early Maastrichtian age based on the presence of Biscutum magnum and Nephrolithus corystus, while one clast yields a late Maastrichtian age based on the presence of Nephrolithus frequens. These samples also contain other characteristic Late Cretaceous species, including Biscutum notaculum, Cribrosphaerella daniae, Eiffellithus gorkae, Kamptnerius magnificus, and Prediscosphaera bukryi. Two samples yield an early Paleocene assemblage dominated by Hornibrookina teuriensis. The Maastrichtian assemblages are similar to those found in the López de Bertodano Formation on Seymour and Snow Hill Islands, making it the likely source area for the Cretaceous clast material. Although no calcareous nannofossils have been reported from Paleocene formations on these islands, the occurrence of calcareous foraminifers suggests other calcareous plankton may be present; thus the Paleocene clasts likely also originated from the Seymour Island area.

Upper Cretaceous planktonic stratigraphy of the Göynük composite section, western Tethys (Bolu province, Turkey)

NASA Astrophysics Data System (ADS)

Wolfgring, Erik; Liu, Shasha; Wagreich, Michael; Böhm, Katharina; Omer Yilmaz, Ismail

2017-04-01

Upper Cretaceous strata exposed at Göynük (Mudurnu-Göynük basin, Bolu Province, Northwestern Anatolia, Turkey) provide a composite geological record from the Upper Santonian to the Maastrichtian. Deposits in this area originate from the Sakarya continent, therefore, a western Tethyan palaeogeographic setting with a palaeolatitude of a bit less than 30 degrees north can be reconstructed. Grey shales and clayey marls are exposed at Göynük and do frequently show volcanic intercalations in the oldest parts of the section, while the uppermost layers depict a more complete deeper-marine record. The pelagic palaeoenvironment, microfossil indicators point towards a distal slope setting, at the Göynük section comprises rich low-latitude planktonic foraminiferal and calcareous nannoplankton assemblages. Benthic foraminifera are scarce, however, some biostratigraphically indicative taxa were recovered. The three sections sampled for this study reveal a composite record from the Campanian Contusotruncana plummerae planktonic foraminifera Zone to the Maastrichtian Racemiguembelina fruticosa planktonic foraminifera Zone. The oldest sub section („GK-section") yields the „mid" Campanian Contusotruncana plummerae or Globotruncana ventricosa Zones and is followed by the „GC-section". The oldest strata in latter record the C. plummerae Zone, the Radotruncana calcarata Zone, Globotruncanita havanensis as well as the Globotruncana aegyptiaca Zone and are overlain by the youngest section examined in this study ("GS -section"). In the latter, we recognize the G. aegyptiaca Zone in the lowermost part, the upper Campanian/lower Maastrichtian Gansserina gansseri Zone, and the Maastrichtian Racemiguembelina fruticosa Zone. Nannofossil standard zones UC15b to UC18 are recorded within the composite section. The planktonic foraminiferal assemblages assessed in the Göynük area feature a well preserved, diverse plankton record that can be correlated to other western Tethyan

A new basal hadrosauroid dinosaur from the Late Cretaceous of Uzbekistan and the early radiation of duck-billed dinosaurs.

PubMed

Sues, Hans-Dieter; Averianov, Alexander

2009-07-22

Levnesovia transoxiana gen. et sp. nov., from the Late Cretaceous (Middle-Late Turonian) of Uzbekistan, is the oldest well-documented taxon referable to Hadrosauroidea sensu Godefroit et al. It differs from a somewhat younger and closely related Bactrosaurus from Inner Mongolia (China) by a tall sagittal crest on the parietals and the absence of club-shaped dorsal neural spines in adult specimens. Levnesovia, Bactrosaurus and possibly Gilmoreosaurus represent the earliest radiation of Hadrosauroidea, which took place during the Cenomanian-Turonian and possibly in North America. The second, Santonian-age radiation of Hadrosauroidea included Aralosaurus, Hadrosauridae and lineages leading to Tanius (Campanian) and Telmatosaurus (Maastrichtian). Hadrosauridae appears to be monophyletic, but Hadrosaurinae and Lambeosaurinae originated in North America and Asia, respectively.

Paleoenvironmental signals and paleoclimatic condition of the Early Maastrichtian oil shales from Central Eastern Desert, Egypt

NASA Astrophysics Data System (ADS)

Fathy, Douaa; Wagreich, Michael; Zaki, Rafat; Mohamed, Ramadan S. A.

2016-04-01

Early Maastrichtian oil shales are hosted in the Duwi Formation of the Central Eastern Desert, Egypt. The examined member represents up to 20% of the total Duwi Formation. This interval is mainly composed of siliciclastic facies, phosphorites facies and carbonate facies. Oil shales microfacies is mainly composed of smectite, kaolinite, calcite, fluorapatite, quartz and pyrite. They are enriched in a number of major elements and trace metals in particular Ca, P, V, Ni, Cr, Sr, Zn, Mo, Nb, U and Y compared to the post-Archaean Australian shale (PAAS). Chondrite-normalized REEs patterns of oil shales for the studied area display light rare earth elements enrichment relatively to heavy rare earth elements with negative Ce/Ce* and Eu/Eu* anomalies. The most remarkable indicators for redox conditions are enrichments of V, Mo, Ni, Cr, U content and depletion of Mn content. Besides, V/V+Ni, V/Ni, U/Th, Ni/Co, authigentic uranium ratios with presence of framboidal shape of pyrite and its size are reflecting the deposition of these shales under marine anoxic to euxinic environmental conditions. Additionally, the ratio of Strontium (Sr) to Barium (Ba) Sr/Ba reflected highly saline water during deposition. Elemental ratios critical to paleoclimate and paleoweathering (Rb /Sr, Al2O3/TiO2), CIA values, binary diagram between (Al2O3+K2O+Na2O) and SiO2 and types of clay minerals dominated reflect warm to humid climate conditions prevailing during the accumulation of these organic-rich petroleum source rocks.

Deep To Shallow, Time Transgressive Shift In The Source Of Bottom Waters On Demerara Rise Inferred From Neodymium Isotopes In Fish Debris

NASA Astrophysics Data System (ADS)

Isaza-Londoño, C.; MacLeod, K. G.; Martin, E. E.; Jiménez Berrocoso

2008-12-01

Between the Campanian and Danian, ɛNd values of fish debris from four sites on Demerara Rise (tropical North Atlantic) shift by ~5 units from -16 to -11. Low values from Campanian and early Maastrichtian samples are similar to values measured on most other Late Cretaceous samples from Demerara sites, whereas the post-shift values are similar to Late Cretaceous and Paleogene values observed at a number of other North Atlantic deep sea sites. In addition, at the two relatively deep sites studied (Ocean Drilling Program [ODP] Sites 1258 and 1260), the shift begins near the base of the Maastrichtian Abathomphalus mayaroensis planktonic foraminifera Zone and values increase over an interval representing several million years of deposition. In two relatively shallow sites (OSP Sites 1259 and 1261), on the other hand, ɛNd values remain low through the highest Cretaceous samples measured, which are from near the top of the Abathomphalus mayaroensis Zone. Therefore, low values persist for several million years longer at the shallower sites. At Site 1259, no Paleogene samples have been analyzed yet, but at Site 1261 values shift from ~-16.5 to ~-13 in samples separated by ~3.5 m and bracketing the Cretaceous/Paleogene (K/T) boundary. Unfortunately, the K/T boundary is not complete at Site 1261, so the relationship to the K/T event is unclear. Ongoing work is focused on constraining the relationship between ɛNd shifts and the K/T boundary using the more complete record at Site 1259 and at examining whether there is any high frequency variation superimposed on the gradual trends observed, especially at the deeper sites. Regardless of the outcome of the these analyses, assuming the low ɛNd values characteristic of most the Late Cretaceous on Demerara Rise are the signature of a locally formed intermediate water mass, the existing data already indicate that the importance of downwelling in the tropical North Atlantic began to wane in the mid- Maastrichtian and had apparently

Small Theropod Teeth from the Late Cretaceous of the San Juan Basin, Northwestern New Mexico and Their Implications for Understanding Latest Cretaceous Dinosaur Evolution

PubMed Central

Williamson, Thomas E.; Brusatte, Stephen L.

2014-01-01

Studying the evolution and biogeographic distribution of dinosaurs during the latest Cretaceous is critical for better understanding the end-Cretaceous extinction event that killed off all non-avian dinosaurs. Western North America contains among the best records of Late Cretaceous terrestrial vertebrates in the world, but is biased against small-bodied dinosaurs. Isolated teeth are the primary evidence for understanding the diversity and evolution of small-bodied theropod dinosaurs during the Late Cretaceous, but few such specimens have been well documented from outside of the northern Rockies, making it difficult to assess Late Cretaceous dinosaur diversity and biogeographic patterns. We describe small theropod teeth from the San Juan Basin of northwestern New Mexico. These specimens were collected from strata spanning Santonian – Maastrichtian. We grouped isolated theropod teeth into several morphotypes, which we assigned to higher-level theropod clades based on possession of phylogenetic synapomorphies. We then used principal components analysis and discriminant function analyses to gauge whether the San Juan Basin teeth overlap with, or are quantitatively distinct from, similar tooth morphotypes from other geographic areas. The San Juan Basin contains a diverse record of small theropods. Late Campanian assemblages differ from approximately co-eval assemblages of the northern Rockies in being less diverse with only rare representatives of troodontids and a Dromaeosaurus-like taxon. We also provide evidence that erect and recurved morphs of a Richardoestesia-like taxon represent a single heterodont species. A late Maastrichtian assemblage is dominated by a distinct troodontid. The differences between northern and southern faunas based on isolated theropod teeth provide evidence for provinciality in the late Campanian and the late Maastrichtian of North America. However, there is no indication that major components of small-bodied theropod diversity were lost

Small theropod teeth from the Late Cretaceous of the San Juan Basin, northwestern New Mexico and their implications for understanding latest Cretaceous dinosaur evolution.

PubMed

Williamson, Thomas E; Brusatte, Stephen L

2014-01-01

Studying the evolution and biogeographic distribution of dinosaurs during the latest Cretaceous is critical for better understanding the end-Cretaceous extinction event that killed off all non-avian dinosaurs. Western North America contains among the best records of Late Cretaceous terrestrial vertebrates in the world, but is biased against small-bodied dinosaurs. Isolated teeth are the primary evidence for understanding the diversity and evolution of small-bodied theropod dinosaurs during the Late Cretaceous, but few such specimens have been well documented from outside of the northern Rockies, making it difficult to assess Late Cretaceous dinosaur diversity and biogeographic patterns. We describe small theropod teeth from the San Juan Basin of northwestern New Mexico. These specimens were collected from strata spanning Santonian - Maastrichtian. We grouped isolated theropod teeth into several morphotypes, which we assigned to higher-level theropod clades based on possession of phylogenetic synapomorphies. We then used principal components analysis and discriminant function analyses to gauge whether the San Juan Basin teeth overlap with, or are quantitatively distinct from, similar tooth morphotypes from other geographic areas. The San Juan Basin contains a diverse record of small theropods. Late Campanian assemblages differ from approximately coeval assemblages of the northern Rockies in being less diverse with only rare representatives of troodontids and a Dromaeosaurus-like taxon. We also provide evidence that erect and recurved morphs of a Richardoestesia-like taxon represent a single heterodont species. A late Maastrichtian assemblage is dominated by a distinct troodontid. The differences between northern and southern faunas based on isolated theropod teeth provide evidence for provinciality in the late Campanian and the late Maastrichtian of North America. However, there is no indication that major components of small-bodied theropod diversity were lost

Geochemistry and mineralogy of the older (> 40 ka) ignimbrites in the Campanian Plain, southern Italy

NASA Astrophysics Data System (ADS)

Belkin, Harvey E.; Raia, Federica; Rolandi, Giuseppe; Jackson, John C.; de Vivo, Benedetto

2010-05-01

The Campanian Plain in southern Italy has been volcanically active during the last 600 ka. The largest and best known eruption at 39 ka formed the Campanian Ignimbrite (CI), which has the largest volume (~310 km3) and the greatest areal extent. However, significant, but scattered deposits of older ignimbrites underlie the CI and document a long history of trachytic eruptions. We examined the geochemistry and mineralogy of 11 older ignimbrite strata by optical petrography, electron microprobe, scanning electron microscope, X-ray diffraction, and various whole-rock geochemical techniques. Strata at Durazzano (116.1 ka), Moschiano (184.7 ka), Seiano Valley A (245.9 ka), Seiano Valley B (289.6 ka), Taurano 7 (205.6 and 210.4 ka), Taurano 9 (183.8 ka), and Taurano 14 (157.4 ka) have been previously dated by the 40Ar/39Ar technique (Rolandi et al., 2003, Min. & Pet., 79) on hand-picked sanidine. The older ignimbrites are trachytic, but are highly altered with LOI from 8 to 17 wt%. Whole-rock compositions reflect variable element mobility during weathering; TiO2, Al2O3, Fe-oxide, and CaO tend to be enriched relative to average CI composition, whereas Na2O and K2O are depleted. X-ray diffraction identified major chabazite, kaolinite, and illite-smectite alteration products in some samples. The phenocryst mineralogy in all of the strata is typical for trachyte magma and consists of plagioclase (~An80 to ~An40), potassium feldspar (~Or50 to ~Or80), biotite (TiO2 = ~4.6 wt%, BaO = ~0.70 wt%, F = ~0.65 wt%), diopside (~Ca47Mg48Fe5 to ~Ca48Mg34Fe18), titanomagnetite, and uncommon Ca-amphibole. Relatively immobile trace elements Zr, Hf, Nb, and Th display similar abundance, linear trends, and ratios as those measured in the Campanian Ignimbrite: Th/Hf = ~4, Zr/Hf = ~50, and Zr/Nb = ~6. The similarity of trace element systematics and phenocryst mineralogy among the Campanian Ignimbrite and the older ignimbrites suggests that the magmagenesis processes and parental source have

Maastrichtian ammonites chiefly from the Prairie Bluff Chalk in Alabama and Mississippi

USGS Publications Warehouse

Cobban, W.A.; Kennedy, W.J.

1995-01-01

The Prairie Bluff Chalk of Alabama and Mississippi yields a diverse ammonite fauna of Maastrichtian age. Twenty-eight species, of which three are new, are recorded. The bulk of the fauna can be referred to a Discoscaphites conradi assemblage zone, but some elements in the fauna are significantly older. -Authors

Quantifying volcanic ash dispersal and impact of the Campanian Ignimbrite super-eruption

NASA Astrophysics Data System (ADS)

Costa, A.; Folch, A.; Macedonio, G.; Giaccio, B.; Isaia, R.; Smith, V. C.

2012-05-01

We apply a novel computational approach to assess, for the first time, volcanic ash dispersal during the Campanian Ignimbrite (Italy) super-eruption providing insights into eruption dynamics and the impact of this gigantic event. The method uses a 3D time-dependent computational ash dispersion model, a set of wind fields, and more than 100 thickness measurements of the CI tephra deposit. Results reveal that the CI eruption dispersed 250-300 km3 of ash over ˜3.7 million km2. The injection of such a large quantity of ash (and volatiles) into the atmosphere would have caused a volcanic winter during the Heinrich Event 4, the coldest and driest climatic episode of the Last Glacial period. Fluorine-bearing leachate from the volcanic ash and acid rain would have further affected food sources and severely impacted Late Middle-Early Upper Paleolithic groups in Southern and Eastern Europe.

Sequence stratigraphic interpretation of parts of Anambra Basin, Nigeria using geophysical well logs and biostratigraphic data

NASA Astrophysics Data System (ADS)

Anakwuba, E. K.; Ajaegwu, N. E.; Ejeke, C. F.; Onyekwelu, C. U.; Chinwuko, A. I.

2018-03-01

The Anambra basin constitutes the southeastern lower portion of the Benue Trough, which is a large structural depression that is divided into lower, middle and upper parts; and is one of the least studied inland sedimentary basins in Nigeria. Sequence stratigraphic interpretation had been carried out in parts of the Anambra Basin using data from three wells (Alo-1 Igbariam-1 and Ajire-1). Geophysical well logs and biostratigraphic data were integrated in order to identify key bounding surfaces, subdivide the sediment packages, correlate sand continuity and interpret the environment of deposition in the fields. Biostratigraphic interpretation, using foraminifera and plankton population and diversity, reveals five maximum flooding surfaces (MFS) in the fields. Five sequence boundaries (SB) were also identified using the well log analysis. Four 3rd order genetic sequences bounded by maximum flooding surfaces (MFS-1 to MFS-6) were identified in the areas; four complete sequences and one incomplete sequence were identified in both Alo-1 and Igbariam-1 wells while Ajire-1 has an no complete sequence. The identified system tracts delineated comprises Lowstand Systems Tracts (progradational to aggradational to retrogradational packages), Transgressive Systems Tracts (retrogradational packages) and Highstand Systems Tracts (aggradational to progradational packages) in each well. The sand continuity across the fields reveal sands S1 to S5 where S1 is present in Ajire-1 well and Igbariam-1 well but not in Alo-1 well. The sands S4 to S5 run across the three fields at different depths. The formations penetrated by the wells starting from the base are; Nkporo Formation (Campanian), Mamu Formation (Late Campanian to Early Maastrichtian), Ajali Sandstone (Maastrichtian), Nsukka Formation (Late Maastrichtian to Early Palaeocene), Imo Formation (Palaeocene) and Nanka Sand (Eocene). The environments of deposition revealed are from coastal to bathyal. The sands of lowstand system

Testing Connections between Campanian Ignimbrite Volcanism, Climate, and the Final Decline of the Neanderthals

NASA Astrophysics Data System (ADS)

Black, B. A.; Manga, M.; Neely, R. R., III

2014-12-01

The eruption of the Campanian Ignimbrite 40,000 years ago coincided approximately with the final decline of the Neanderthals and a technological and cultural transition from the Middle to Upper Paleolithic. Two end-member hypotheses have been advanced to explain Neanderthal decline: competition with anatomically modern humans and failure to adapt in the face of environmental stresses. The eruption of the Campanian Ignimbrite has been cited as a potentially major cause of such environmental stress. In this work, we draw on published datasets including ice core records, maps and simulations of ash dispersal, and petrologic measurements to constrain the characteristics of the Campanian Ignimbrite eruption. To investigate the climatic effects of the eruption, we use a three-dimensional sectional aerosol model to simulate the global aerosol cloud after 25 Tg and 100 Tg sulfur release scenarios. We couple these aerosol properties to a comprehensive earth system model under last glacial conditions. We find that summer temperatures were colder for several years after the eruption, with some simulations predicting temperature decreases of up to 10 degrees in Eastern Europe and Asia. While this cold interval may have impacted hominid communities in Siberia, the overall distribution of the cooling we observe in our model is inconsistent with catastrophic collapse of Neanderthal populations in Europe. Nonetheless, the volcanic cooling could have influenced daily life for a generation of Neanderthals and anatomically modern humans.

Upper Maastrichtian ammonite biostratigraphy of the Gulf Coastal Plain (Mississippi Embayment, southern USA)

USGS Publications Warehouse

Larina, Ekaterina; Garb, Matthew P.; Landman, Neil H.; Dastas, Natalie; Thibault, Nicolas; Edwards, Lucy E.; Phillips, George; Rovelli, Remy; Myers, Corinne; Naujokaityte, Jone

2016-01-01

The Cretaceous outcrop belt of the Mississippi Embayment in the Gulf Coastal Plain (GCP) spans the Cretaceous/Paleogene (K/Pg) boundary. A detailed reconstruction of this time interval is critical for understanding the nature of biotic and environmental changes preceding the end-Cretaceous Mass Extinction event and for deciphering the likely extinction mechanism (i.e., bolide impact versus volcanism). Eight sections encompassing the K/Pg succession across the Mississippi Embayment were analyzed using biostratigraphic sampling of ammonites, dinoflagellates, and nannofossils. An upper Maastrichtian ammonite zonation is proposed as follows, from oldest to youngest:Discoscaphites conradi Zone, D. minardi Zone, and D. iris Zone. Our study documents that the ammonite zonation established in the Atlantic Coastal Plain (ACP) extends to the GCP. This zonation is integrated with nannofossil and dinoflagellate biostratigraphy to provide a framework to more accurately determine the age relationships in this region. We demonstrate that ammonites and dinoflagellates are more reliable stratigraphic indicators in this area than nannofossils because age-diagnostic nannofossils are not consistently present within the upper Maastrichtian in the GCP. This biostratigraphic framework has the potential to become a useful tool for correlation of strata both within the GCP and between the GCP, Western Interior, and ACP. The presence of the uppermost Maastrichtian ammonite D. iris, calcareous nannofossil Micula prinsii, and dinoflagellates Palynodinium grallator and Disphaerogena carposphaeropsis suggests that the K/Pg succession in the GCP is nearly complete. Consequently, the GCP is an excellent setting for investigating fine scale temporal changes across the K/Pg boundary and ultimately elucidating the mechanisms causing extinction.

Bentonite chemical features as proxy of late Cretaceous provenance changes: A case study from the Western Interior Basin of Canada

NASA Astrophysics Data System (ADS)

Fanti, Federico

2009-05-01

Bentonite beds are fairly common in both marine and terrestrial Upper Cretaceous (Campanian-Maastrichtian) deposits of the Western Interior Basin of western Canada and northwestern United States. A detailed stratigraphic, sedimentologic, geochemical (X-ray fluorescence), and mineralogical (X-ray diffraction) study of twenty-one bentonites from the Puskwaskau and Wapiti formations in the Grande Prairie area (west-central Alberta, Canada) is here presented. Major and trace-element concentrations from altered volcanic ashes document the presence in the study area of predominantly trachyandesitic and rhyolitic volcanogenic products, resulted from intense volcanic arc to within-plate pyroclastic activity. Concentration values of high field strength elements (HFSE) and selected large ion lithophile elements (LILE) (e.g. Nb, Zr, Th, and Y) obtained by X-ray fluorescence spectroscopy strongly support the presence of multiple volcanic sources. Integrated paleoenvironmental and geochemical criteria for provenance determination indicate a bimodal occurrence of basic and acid volcanic products interpreted as reflection of source areas characterized by different tectonic setting and magmatic composition. A comparative analysis of geochemical compositions between Grande Prairie bentonites and 30 known volcanic beds from central and southern Alberta, Manitoba and Montana 1. documents a trend toward more acidic and alkali-depleted volcanic products during the late Campanian-early Maastrichtian interval, and 2. suggests a well constrained stratigraphic and geographic subdivision of the non-marine successions of the foreland basin on the basis of geochemical characteristic of volcanic ash beds. Furthermore, geochemical "fingerprints" of several decimeter to meter thick bentonite beds have been coupled with volcanic ash subsurface signature in order to investigate their role as marker beds. This multiple-approach provides a reliable tool for basin-scale identification and correlation

Attenuation tomography of the main volcanic regions of the Campanian Plain.

NASA Astrophysics Data System (ADS)

de Siena, Luca; Del Pezzo, Edoardo; Bianco, Francesca

2010-05-01

Passive, high resolution attenuation tomography is used to image the geological structure in the first upper 4 km of shallow crust beneath the Campanian Plain. Images were produced by two separate attenuation tomography studies of the main volcanic regions of the Campanian Plain, Southern Italy, Mt. Vesuvius volcano and Campi Flegrei caldera. The three-dimensional S wave attenuation tomography of Mt. Vesuvius has been obtained with multiple measurements of coda-normalized S-wave spectra of local small magnitude earthquakes. P-wave attenuation tomography was performed using classical spectral methods. The images were obtained inverting the spectral data with a multiple resolution approach expressively designed for attenuation tomography. This allowed to obtain a robust attenuation image of the volumes under the central cone at a maximum resolution of 300 m. The same approach was applied to a data set recorded in the Campi Flegrei area during the 1982-1984 seismic crisis. Inversion ensures a minimum cell size resolution of 500 meters in the zones with sufficient ray coverage, and 1000 meters outside these zones. The study of the resolution matrix as well as the synthetic tests guarantee an optimal reproduction of the input anomalies in the center of the caldera, between 0 and 3.5 km in depth. Results allowed an unprecedented view of several features of the medium, like the residual part of solidified magma from the last eruption, under the central cone of Mt. Vesuvius, and the feeding systems and top of the carbonate basement, 3 km depth below both volcanic areas. Vertical Q contrast image important fault zones, such as the La Starza fault, as well as high attenuation structures that correspond to gas or fluid reservoirs, and reveal the upper part of gas bearing conduits connecting these high attenuation volumes with the magma sill revealed at about 7 km in depth by passive travel-time tomography under the whole Campanian Plain.

A critical review of seismotectonic setting of the Campanian Plain (Southern Italy) in GIS environment.

NASA Astrophysics Data System (ADS)

Gaudiosi, Germana; Alessio, Giuliana; Luiso, Paola; Nappi, Rosa; Ricciolino, Patrizia

2010-05-01

The Plio-Pleistocene Campanian Plain is a structural depression of the Southern Italy located between the eastern side of the Tyrrhenian Sea and the Southern Apennine chain. It is surrounded to the North, East and South by the Mesozoic carbonate massifs of the Apennine chain and, to the West, by the Tyrrhenian Sea. The graben origin is similar to other peri-Tyrrhenian regions and is related to a stretching and thinning of the continental crust by the counterclockwise rotation of the Italian peninsula and the contemporaneous opening of the Tyrrhenian sea. The consequent subsidence of the Campanian carbonate platform took place along the Tyrrhenian coast during the Plio-Pleistocene with a maximum vertical extent of 5 km. The plain is filled by volcanic and clastic, continental and marine deposits. Voluminous volcanic activity of Roccamonfina, Campi Flegrei, Ischia, Procida and Vesuvio occurred in the Plain during the Quaternary. In the middle of the plain lies the city of Naples, bordered by the two active volcanoes of Campi Flegrei and Vesuvio. It is a very densely inhabited area that is exposed to high potential volcanic risk. The stress field acting in the Campanian area is poorly known. Structural observations on the Pleistocene faults suggest normal to sinistral movements for the NW- SE-trending faults and normal to dextral for the NE-SW-trending structures. These movements are consistent with those of the structures affecting the inner margin of the Southern Apennines. The Campanian Plain is characterized by seismicity of energy lower than the seismic activity of the Southern Apennine chain. The earthquakes mainly occur along the margin of the plain, in the volcanic areas and a minor seismicity spreads out inside the Plain. The aim of this paper is an attempt to identify active, outcropping and buried fault systems of the Campanian plain through the correlation between seismicity and tectonic structures. Seismic, geologic and geomorphologic data have been

Geology and taphonomy of the L'Espinau dinosaur bonebed, a singular lagoonal site from the Maastrichtian of South-Central Pyrenees

NASA Astrophysics Data System (ADS)

Fondevilla, V.; Vicente, A.; Battista, F.; Sellés, A. G.; Dinarès-Turell, J.; Martín-Closas, C.; Anadón, P.; Vila, B.; Razzolini, N. L.; Galobart, À.; Oms, O.

2017-06-01

The L'Espinau site is a dinosaur bonebed from the Upper Cretaceous of the South-Central Pyrenees (north-eastern Spain) that have provided hundreds of bone remains attributed to hadrosauroids, together with a rich assemblage of herpetofauna, fish and microflora. Magnetostratigraphy calibrated the site with the early late Maastrichtian, and the combined sedimentology, stable isotope geochemistry and palaeoecology revealed that this fossil site formed in a lagoon, in which a mixed freshwater-brackish palaeoenvironment was developed. This setting displays a south-north charophyte zonation from freshwater (Clavator brachycerus-dominated assemblage) to brackish or eurihaline conditions (Feistiella malladae-dominated assemblage), revealing a palaeoenvironment change towards the coast. Sedimentology and taphonomy (bidirectional arrangement of long bones, abrasion and disarticulation) indicate that the L'Espinau site is the result of a cohesive mass flow event originated very close to the sea. This process entrained and mixed fauna from both the terrestrial and the brackish/marine environment of a lagoon. An increasing of the water runoff (e.g. by intense rainfall) reworking poorly consolidated sediments is considered here as the most probable triggering mechanism. Mass flow-hosted bonebeds are commonly linked to fluvial palaeoenvironments, so our study case is a rare example of bones accumulating near the sea. This study adds evidence that hadrosauroids inhabited littoral environments during the Maastrichtian in the southern Pyrenean area.

The Breccia Museo formation, Campi Flegrei, southern Italy: Geochronology, chemostratigraphy and relationship with the Campanian Ignimbrite eruption

USGS Publications Warehouse

Fedele, L.; Scarpati, C.; Lanphere, M.; Melluso, L.; Morra, V.; Perrotta, A.; Ricci, G.

2008-01-01

The Breccia Museo is one of the most debated volcanic formations of the Campi Flegrei volcanic district. The deposit, made up of six distinctive stratigraphic units, has been interpreted by some as the proximal facies of the major caldera-forming Campanian Ignimbrite eruption, and by others as the product of several, more recent, independent and localized events. New geochemical and chemostratigraphical data and Ar - Ar age determinations for several units of the Breccia Museo deposits (???39 ka), correlate well with the Campanian Ignimbrite-forming eruption. The chemical zoning of the Breccia Museo deposits is interpreted here to be a consequence of a three-stage event that tapped a vertically zoned trachytic magma chamber. ?? Springer-Verlag 2008.

Evolution of the Campanian Ignimbrite Magmatic System II: Trace Element and Th Isotopic Evidence for Open-System Processes

NASA Astrophysics Data System (ADS)

Bohrson, W. A.; Spera, F. J.; Fowler, S.; Belkin, H.; de Vivo, B.

2005-12-01

The Campanian Ignimbrite, a large volume (~200 km3 DRE) trachytic to phonolitic ignimbrite was deposited at ~39.3 ka and represents the largest of a number of highly explosive volcanic events in the region near Naples, Italy. Thermodynamic modeling of the major element evolution using the MELTS algorithm (see companion contribution by Fowler et al.) provides detailed information about the identity of and changes in proportions of solids along the liquid line of descent during isobaric fractional crystallization. We have derived trace element mass balance equations that explicitly accommodate changing mineral-melt bulk distribution coefficients during crystallization and also simultaneously satisfy energy and major element mass conservation. Although major element patterns are reasonably modeled assuming closed system fractional crystallization, modeling of trace elements that represent a range of behaviors (e.g. Zr, Nb, Th, U, Rb, Sm, Sr) yields trends for closed system fractionation that are distinct from those observed. These results suggest open-system processes were also important in the evolution of the Campanian magmatic system. Th isotope data yield an apparent isochron that is ~20 kyr younger than the age of the deposit, and age-corrected Th isotope data indicate that the magma body was an open-system at the time of eruption. Because open-system processes can profoundly change isotopic characteristics of a magma body, these results illustrate that it is critical to understand the contribution that open-system processes make to silicic magma bodies prior to assigning relevance to age or timescale information derived from isotope systematics. Fluid-magma interaction has been proposed as a mechanism to change isotopic and elemental characteristics of magma bodies, but an evaluation of the mass and thermal constraints on such a process suggest large-scale fluid-melt interaction at liquidus temperatures is unlikely. In the case of the magma body associated with

Late cretaceous foraminifera, paleoenvironments, and paleoceanography of the rosario formation, San Antonio del Mar, Baja California, Mexico

USGS Publications Warehouse

Maestas, Y.; MacLeod, K.G.; Douglas, R.; Self-Trail, J.; Ward, P.D.

2003-01-01

The 315 m of Rosario Formation exposed at the San Antonio del Mar (SADM) section (Baja California, Mexico) contains moderately-to-well preserved benthic and planktic foraminifera, calcareous nannofossils, and molluscs. Nannofossils suggest most of the SADM section was deposited within a narrow interval of the late Campanian (CC21-CC22), whereas foraminifera and molluscs suggest a younger maximum age (younger than the Globotruncana ventricosa Zone) and allow deposition over a longer interval of time. Planktic foraminifera at SADM represent common Tethyan taxa. They are largely restricted to the lower and middle portions of the section and comprise 0-???40% of foraminiferal assemblages. Stable isotopic analyses of Rugoglobigerina rugosa yield ??18OV-PDB values from -2.27%, to -2.82%, corresponding to salinity-corrected paleotemperature estimates of 26-30??C for the Late Cretaceous eastern Pacific. These estimates are as warm as modern tropical temperatures and are similar to tropical paleotemperature estimates from ??18O analyses of exceptionally preserved Maastrichtian samples; however, they are considerably warmer than most tropical Campanian-Maastrichtian estimates. Benthic foraminifera indicate outer shelf paleodepths with a slight increase in depth or decrease in benthic oxygen levels in the upper parts of the interval studied. The change in the benthic assemblage corresponds to an ???1??? positive shift in benthic ??O18, suggesting a relationship between benthic assemblages and an inferred increase in the local intensity of upwelling.

Early on-orbit calibration results from Aqua MODIS

NASA Astrophysics Data System (ADS)

Xiong, Xiaoxiong; Barnes, William L.

2003-04-01

Aqua MODIS, also known as the MODIS Flight Model 1 (FM1), was launched on May 4, 2002. It opened its nadir aperture door (NAD) on June 24, 2002, beginning its Earth observing mission. In this paper, we present early results from Aqua MODIS on-orbit calibration and characterization and assess the instrument's overall performance. MODIS has 36 spectral bands located on four focal plane assemblies (FPAs). Bands 1-19, and 26 with wavelengths from 0.412 to 2.1 microns are the reflective solar bands (RSB) that are calibrated on-orbit by a solar diffuser (SD). The degradation of the SD is tracked using a solar diffuser stability monitor (SDSM). The bands 20-25, and 27-36 with wavelengths from 3.75 to 14.5 microns are the thermal emissive bands (TEB) that are calibrated on-orbit by a blackbody (BB). Early results indicate that the on-orbit performance has been in good agreement with the predications determined from pre-launch measurements. Except for band 21, the low gain fire band, band 6, known to have some inoperable detectors from pre-launch characterization, and one noisy detector in band 36, all of the detectors' noise characterizations are within their specifications. Examples of the sensor's short-term and limited long-term responses in both TEB and RSB will be provided to illustrate the sensor's on-orbit stability. In addition, we will show some of the improvements that Aqua MODIS made over its predecessor, Terra MODIS (Protoflight Model - PFM), such as removal of the optical leak into the long-wave infrared (LWIR) photoconductive (PC) bands and reduction of electronic crosstalk and out-of-band (OOB) thermal leak into the short-wave infrared (SWIR) bands.

Tidal friction and the early history of the moon's orbit

NASA Technical Reports Server (NTRS)

Rubincam, D. P.

1975-01-01

The present work investigates the consequences implied by various rheological models of the early earth for the orbital history of the moon subsequent to its formation. Models of the earth that yield small tidal angles, such as low-viscosity models, imply that the moon never orbited in the earth's equatorial plane, thereby ruling out an equatorial origin for the moon. A high-viscosity model is shown to permit the moon to originate in the equatorial plane and still account for the present-day characteristics of the moon's orbit.

A multidisciplinary approach to reservoir subdivision of the Maastrichtian chalk in the Dan field, Danish North Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kristensen, L.; Dons, T.; Schioler, P.

1995-11-01

Correlation of wireline log data from the North Sea chalk reservoirs is frequently hampered by rather subtle log patterns in the chalk section due to the apparent monotonous nature of the chalk sediments, which may lead to ambiguous correlations. This study deals with a correlation technique based on an integration of biostratigraphic data, seismic interpretation, and wireline log correlation; this technique aims at producing a consistent reservoir subdivision that honors both the well data and the seismic data. This multidisciplinary approach has been used to subdivide and correlate the Maastrichtian chalk in the Dan field. The biostratigraphic subdivision is basedmore » on a new detailed dinoflagellate study of core samples from eight wells. Integrating the biostratigraphic results with three-dimensional seismic data allows recognition of four stratigraphic units within the Maastrichtian, bounded by assumed chronostratigraphic horizons. This subdivision is further refined by adding a seismic horizon and four horizons from wireline log correlations, establishing a total of nine reservoir units. The approximate chronostratigraphic nature of these units provides an improved interpretation of the depositional and structural patterns in this area. The three upper reservoir units pinch out and disappear in a northeasterly direction across the field. We interpret this stratal pattern as reflecting a relative sea level fall or regional basinal subsidence during the latest Maastrichtian, possibly combined with local synsedimentary uplift due to salt tectonics. Isochore maps indicate that the underlying six non-wedging units are unaffected by salt tectonics.« less

Middle Cretaceous to Oligocene rise of the Middle American landbridge - documented by south-eastwards younging shallow water carbonates

NASA Astrophysics Data System (ADS)

Baumgartner-Mora, Claudia; Baumgartner, Peter O.; Barat, Flore

2013-04-01

Basements of Southern Central America are oceanic in origin, including the southern half of the classical "Chortis Block" formed by subduction/accretion mélanges named Mesquito Composite Oceanic Terrane (MCOT). The rise of these oceanic basements into the photic zone and eventual emergence was controlled by convergent, collision tectonics, and/or arc development. In this context, shallow carbonate palaeo-environments were short-lived and formed not only on uplifted basements and arcs, but also on (now accreted) volcanic edifices of Pacific oceanic seamounts. From Northern Nicaragua (NW) to Eastern Panama (SE) we observe a systematic younging of the first shallow water carbonate facies encroaching on basements and/or older deep-water formations: In the Siuna area (NE-Nicaragua) Aptian-Albian shallow water limestones dated by rudists and Orbitolina texana rest unconformably on the Jurassic/Early Cretaceous Siuna Serpentinite Mélange, part of the MCOT. In N-Costa Rica, the assembly of several terranes (Santa Elena Ultramafic Unit, Nicoya Complex s. s., Matambu and Manzanillo Terranes) is overlapped by Late Campanian-Maastrichtian shallow water facies dated by rudists and Larger Foraminifera, such as Pseudorbitoides rutteni, Pseudorbitoides israelski, Sulcoperculina sp. and Sulcoperculina globosa. Reworked Campanian-Maastrichtian shallow water material including Larger Foraminifera was found in the Herradura Promontory (central Pacific coast of Costa Rica). It could be derived from an accreted seamount. No shallow carbonates are known so far from the early Palaeocene. The Tempisque Basin (N-Costa Rica) hosts the Barra Honda carbonate Platform (originally >900 km2) dated as late Palaeocene (Thanetian) by planktonic Foraminifera, 87Sr / 86Sr ratios and Ranikothalia spp. Other late Palaeocene shallow carbonates documented in S-Costa Rica/W-Panama (Quepos, Burica) are interpreted as insular carbonate shoals (atolls?) on now accreted seamounts. To the SE of the S

Aquarius Radiometer Performance: Early On-Orbit Calibration and Results

NASA Technical Reports Server (NTRS)

Piepmeier, Jeffrey R.; LeVine, David M.; Yueh, Simon H.; Wentz, Frank; Ruf, Christopher

2012-01-01

The Aquarius/SAC-D observatory was launched into a 657-km altitude, 6-PM ascending node, sun-synchronous polar orbit from Vandenberg, California, USA on June 10, 2011. The Aquarius instrument was commissioned two months after launch and began operating in mission mode August 25. The Aquarius radiometer meets all engineering requirements, exhibited initial calibration biases within expected error bars, and continues to operate well. A review of the instrument design, discussion of early on-orbit performance and calibration assessment, and investigation of an on-going calibration drift are summarized in this abstract.

Late Maastrichtian foraminiferids and diatoms from the Polish Carpathians (Ropianka Formation, Skole Nappe): a case study from the Chmielnik-Grabówka composite section

NASA Astrophysics Data System (ADS)

Gasiński, M. Adam; Olshtynska, Alexandra; Uchman, Alfred

2013-12-01

Gasiński, M.A., Olshtynska, A. and Uchman, A. 2013. Late Maastrichtian foraminiferids and diatoms from the Polish Carpathians (Ropianka Formation, Skole Nappe): a case study from the Chmielnik-Grabowka composite section. Acta Geologica Polonica, 63(4), 515-525. Warszawa. Well-preserved foraminiferids have been found in the Chmielnik-Grabowka section (Skole Nappe, Polish Carpathians). The Abathomphalus mayaroensis (late Maastrichtian) and Racemiguembelina fructicosa (earlylate Maastrichtian) standard planktonic foraminiferal biozones have been recognized, based on the occurrence of their respective index species. Sediments of the R. fructicosa Zone contain diatoms, which are a rare component of Cretaceous flysch microfossil assemblages in the Carpathians. The diatom frustules and some foraminiferid tests are pyritized, probably after burial in the sediment, below the redox boundary or in the oxygen- deficient microenvironment inside the frustules or tests of microfossils; the presence of trace fossils and bioturbational structures in the same bed indicate an oxygenated sea floor.

Gateways and Water Mass Mixing in the Late Cretaceous North Atlantic

NASA Astrophysics Data System (ADS)

Asgharian Rostami, M.; Martin, E. E.; MacLeod, K. G.; Poulsen, C. J.; Vande Guchte, A.; Haynes, S.

2017-12-01

Regions of intermediate/deep water formation and water-mass mixing in the North Atlantic are poorly defined for the Late Cretaceous, a time of gateway evolution and cooler conditions following the Mid Cretaceous greenhouse. Improved proxy data combined with modeling efforts are required to effectively evaluate the relationship between CO2, paleogeography, and circulation during this cooler interval. We analyzed and compiled latest Cretaceous (79 - 66 Ma) ɛNd and δ13C records from seven bathyal (paleodepths 0.2 - 2 km) and eight abyssal (paleodepths > 2 km) sites in the North Atlantic. Data suggest local downwelling of Northern Component Water (NCW; ɛNd -9.5 and δ13C 1.7 ‰) is the primary source of intermediate/deep water masses in the basin. As this water flows southward and ages, δ13C values decrease and ɛNd values increase; however, additional chemical changes at several sites require mixing with contributions from several additional water masses. Lower ɛNd ( -10) and higher δ13C ( 1.9 ‰) values in the deep NW part of the basin indicate proximal contributions from a region draining old continental crust, potentially representing deep convection following opening of the Labrador Sea. In the deep NE Iberian Basin, higher ɛNd ( -7) and lower δ13C ( 0.8 ‰) during the Campanian suggest mixing with a Tethyan source (ɛNd -7 and δ13C 0.1 ‰) whose importance decreased with restriction of that gateway in the Maastrichtian. Data from bathyal sites suggest additional mixing. In the SE Cape Verde region, observed ɛNd variations from -10 in the Campanian to -13 and -12 in the early and late Maastrichtian, respectively, may record variations in output rates of Tethyan and/or NCW sources and Demerara Bottom Water (ɛNd -16), a proposed warm saline intermediate water mass formed in shallow, equatorial seas. Pacific inflow through the Caribbean gateway impacts intermediate sites at Blake Nose (ɛNd values -8), particularly the shallowest site during the late

High resolution 40AR/39AR chronostratigraphy of the Late Cretaceous El Gallo Formation, Baja California del Norte, Mexico

NASA Astrophysics Data System (ADS)

Renne, Paul R.; Fulford, Madeleine M.; Busby-Spera, Cathy

1991-03-01

Laser probe 40Ar/39Ar analyses of individual sanidine grains from four tuffs in the alluvial Late Cretaceous (Campanian) El Gallo Formation yield statistically distinct mean dates ranging from 74.87±0.05 Ma to 73.59±0.09 Ma. The exceptional precision of these dates permits calculation of statistically significant sediment accumulation rates that are much higher than passive sediment loading would cause, implying rapid tectonically induced subsidence. The dates bracket tightly the age of important dinosaur and mammalian faunas previously reported from the El Gallo Formation. The dates support an age less than 73 Ma for the Campanian/Maastrichtian stage boundary, younger than indicated by several currently used time scales. Further application of the single grain 40Ar/39Ar technique may be expected to greatly benefit stratigraphic studies of Mesozoic sedimentary basins and contribute to calibration of biostratigraphic and magnetostratigraphic time scales.

Sedimentology and carbon-isotope stratigraphy of the Late Cretaceous Chalk Group in the Höllviken-1 core (SW Sweden)

NASA Astrophysics Data System (ADS)

Bøttger, Dorthe; Thibault, Nicolas; Anderskouv, Kresten

2016-04-01

The Höllviken-1 borehole is situated on the Skåne peninsula (SW Sweden) which was part of the Danish Basin in the Late Cretaceous. 1415 meters have been cored among which ca. 1100 meters cover the complete Upper Cretaceous to lower Danian Chalk Group. Besides the publication of a synthetic log and detailed foraminifer biozonation, supplemented by a number of rare macrofossil findings and description of a number of foraminifer holotypes (Brötzen, 1944), very few studies of the core have actually been performed, since the mid 1940s. A new project has thus been undertaken aiming at improving the stratigraphy of the Chalk Group in the Höllviken-1 core. The data presented here comprise the description of the interval 837-489 m covering a large part of the Campanian and the lower Maastrichtian. Two intervals with the presence of sand are noted in the Campanian and two intervals showing possibly progradational sequences of arenaceous marls to sand are present in the Maastrichtian. The purpose of this new study is to revise the foraminifer biostratigraphy of Brötzen and complement it with high-resolution carbon-isotope stratigraphy in order to establish a new age-model for the core and better constrain the timing of siliciclastic input into the Danish Basin. In addition, high-resolution sedimentological data will be used as a preliminary test for cyclostratigraphy of the chalk-marl intervals.

Phylogeny, Histology and Inferred Body Size Evolution in a New Rhabdodontid Dinosaur from the Late Cretaceous of Hungary

PubMed Central

Ősi, Attila; Prondvai, Edina; Butler, Richard; Weishampel, David B.

2012-01-01

Background Rhabdodontid ornithopod dinosaurs are characteristic elements of Late Cretaceous European vertebrate faunas and were previously collected from lower Campanian to Maastrichtian continental deposits. Phylogenetic analyses have placed rhabdodontids among basal ornithopods as the sister taxon to the clade consisting of Tenontosaurus, Dryosaurus, Camptosaurus, and Iguanodon. Recent studies considered Zalmoxes, the best known representative of the clade, to be significantly smaller than closely related ornithopods such as Tenontosaurus, Camptosaurus, or Rhabdodon, and concluded that it was probably an island dwarf that inhabited the Maastrichtian Haţeg Island. Methodology/Principal Findings Rhabdodontid remains from the Santonian of western Hungary provide evidence for a new, small-bodied form, which we assign to Mochlodon vorosi n. sp. The new species is most similar to the early Campanian M. suessi from Austria, and the close affinities of the two species is further supported by the results of a global phylogenetic analysis of ornithischian dinosaurs. Bone histological studies of representatives of all rhabdodontids indicate a similar adult body length of 1.6–1.8 m in the Hungarian and Austrian species, 2.4–2.5 m in the subadults of both Zalmoxes robustus and Z. shqiperorum and a much larger, 5–6 m adult body length in Rhabdodon. Phylogenetic mapping of femoral lengths onto the results of the phylogenetic analysis suggests a femoral length of around 340 mm as the ancestral state for Rhabdodontidae, close to the adult femoral lengths known for Zalmoxes (320–333 mm). Conclusions/Significance Our analysis of body size evolution does not support the hypothesis of autapomorhic nanism for Zalmoxes. However, Rhabdodon is reconstructed as having undergone autapomorphic giantism and the reconstructed small femoral length (245 mm) of Mochlodon is consistent with a reduction in size relative to the ancestral rhabdodontid condition. Our results imply a pre

Soft sediment deformation structures in the Maastrichtian Ajali Formation Western Flank of Anambra Basin, Southern Nigeria

NASA Astrophysics Data System (ADS)

Olabode, Solomon Ojo

2014-01-01

Soft sediment deformation structures were recognized in the Maastrichtian shallow marine wave to tide influenced regressive sediments of Ajali Formation in the western flank of Anambra basin, southern Nigerian. The soft sediment deformation structures were in association with cross bedded sands, clay and silt and show different morphological types. Two main types recognised are plastic deformations represented by different types of recumbent folds and injection structure represented by clastic dykes. Other structures in association with the plastic deformation structures include distorted convolute lamination, subsidence lobes, pillars, cusps and sand balls. These structures are interpreted to have been formed by liquefaction and fluidization mechanisms. The driving forces inferred include gravitational instabilities and hydraulic processes. Facies analysis, detailed morphologic study of the soft sediment deformation structures and previous tectonic history of the basin indicate that the main trigger agent for deformation is earthquake shock. The soft sediment deformation structures recognised in the western part of Anambra basin provide a continuous record of the tectonic processes that acted on the regressive Ajali Formation during the Maastrichtian.

Multiphase Structural Evolution of a Continental Margin During Obduction Orogeny: Insights From the Jebel Akhdar Dome, Oman Mountains

NASA Astrophysics Data System (ADS)

Grobe, A.; Virgo, S.; von Hagke, C.; Urai, J. L.; Littke, R.

2018-03-01

The structural evolution of the carbonate platform in the footwall of the Semail ophiolite emplaced onto the passive continental margin of Arabia helps to better understand the early stages of obduction-related orogens. These early stages are rarely observable in other orogens as they are mostly overprinted by later mountain building phases. We present an extensive structural analysis of the Jebel Akhdar anticline, the largest tectonic window of the Oman Mountains, and integrate it on different scales. Outcrop observations can be linked to plate motion data, providing an absolute timeframe for structural generations consistent with radiometric dating of veins. Top-to-S overthrusting of the Semail ophiolite and Hawasina nappes onto the carbonate platform during high plate convergence rates between Arabia and Eurasia caused rapid burial and overpressure, generation and migration of hydrocarbons, and bedding-confined veins, but no major deformation in the carbonate platform. At reduced convergence rates, subsequent tectonic thinning of the ophiolite took place above a top-to-NNE, crustal-scale ductile shear zone, deforming existing veins and forming a cleavage in clay-rich layers in early Campanian times. Ongoing extension occurred along normal- to oblique-slip faults, forming horst-graben structures and a precursor of the Jebel Akhdar dome (Campanian to Maastrichtian). This was followed by NE-SW oriented ductile shortening and the formation of the Jebel Akhdar dome, deforming the earlier structures. Thereafter, exhumation was associated with low-angle normal faults on the northern flank of the anticline. We correlate the top-to-NNE crustal-scale shear zone with a similar structure in the Saih Hatat window to develop a unified model of the tectonic evolution of the Oman Mountains.

Correlation of the major late Jurassic —early Tertiary low- and highstand cycles of south-west Egypt and north-west Sudan

NASA Astrophysics Data System (ADS)

Wycisk, Peter

1994-12-01

The mainly continental deposits of northwest Sudan and south-west Egypt have been correlated with coeval shallow marine and marine deposits in northern Egypt along a north-south running cross-section, based on surface and subsurface data. The palaeodepth curve of northern Egypt illustrates the gradual seal-level rise, reaching its maximum during the Late Cretaceous with conspicuous advances during the Aptian and late Cenomanian. A general highstand is also recorded during the Campanian-Maastrichtian in north-west Sudan. A detailed facies correlation is given for the Aptian and late Cenomanian highstand in western Egypt. The correlation of the Cenomanian Bahariya and Maghrabi formations displays short-term relative sealevel fluctuations. The interpretation illustrates the extensiveness of related erosional processes in the hinterland, partly intensified by temporarily uplift of the Uweinat-Aswan High in the south. Regional uplift and constant erosion took place in south-west Egypt during Coniacian and Santonian times. The regional stratigraphic gaps and uncertain interpretation of the Bahariya Uplift are induced by the influence of the Trans-African Lineament, especially during the Late Cretaceous. Low-stand fluvial sheet sandstones characterized by non-cyclic sequence development and high facies stability occur, especially in the Neocomian and early Turonian. During the Barremian and Albian, fluvial architecture changes to more cyclic fluvial sequences and increasing soil formation, due to increasing subsidence, more humid climatic conditions and the generally rising sea level, culminating in the extensive shallow marine Abu Ballas and Maghrabi formations.

Nannofossil biostratigraphy, strontium and carbon isotope stratigraphy, cyclostratigraphy and an astronomically calibrated duration of the Late Campanian Radotruncana calcarata Zone

PubMed Central

Wagreich, Michael; Hohenegger, Johann; Neuhuber, Stephanie

2012-01-01

A section from the southern (Austro-Alpine Northern Calcareous Alps) margin of the Penninic Ocean in the NW Tethys realm of Late Campanian age is investigated stratigraphically. Plankton foraminifer and nannofossil biostratigraphy designate the presence of the Globotruncana ventricosa Zone and the Radotruncana (Globotruncanita) calcarata Zone, and standard nannofossil zones CC21–UC15cTP and CC22ab–UC15deTP. The combination of carbon isotope stratigraphy, strontium isotopes, and cyclostratigraphy allows a detailed chronostratigraphic correlation. Periodicity was obtained by power spectral analysis, sinusoidal regression, and Morlet wavelets. The duration of the calcarata Total Range Zone is calculated by orbital cyclicity expressed in thickness data of limestone–marl rhythmites and stable carbon isotope data. Precessional, obliquity, and short and long eccentricity cycles are identified and give an extent of c. 806 kyr for the zone. Mean sediment accumulation rates are as low as 1.99 cm/kyr and correspond well to sediment accumulation rates in similar settings. We further discuss chronostratigraphic implications of our data. PMID:27087718

Nannofossil biostratigraphy, strontium and carbon isotope stratigraphy, cyclostratigraphy and an astronomically calibrated duration of the Late Campanian Radotruncana calcarata Zone.

PubMed

Wagreich, Michael; Hohenegger, Johann; Neuhuber, Stephanie

2012-12-01

A section from the southern (Austro-Alpine Northern Calcareous Alps) margin of the Penninic Ocean in the NW Tethys realm of Late Campanian age is investigated stratigraphically. Plankton foraminifer and nannofossil biostratigraphy designate the presence of the Globotruncana ventricosa Zone and the Radotruncana ( Globotruncanita ) calcarata Zone, and standard nannofossil zones CC21-UC15c TP and CC22ab-UC15de TP . The combination of carbon isotope stratigraphy, strontium isotopes, and cyclostratigraphy allows a detailed chronostratigraphic correlation. Periodicity was obtained by power spectral analysis, sinusoidal regression, and Morlet wavelets. The duration of the calcarata Total Range Zone is calculated by orbital cyclicity expressed in thickness data of limestone-marl rhythmites and stable carbon isotope data. Precessional, obliquity, and short and long eccentricity cycles are identified and give an extent of c. 806 kyr for the zone. Mean sediment accumulation rates are as low as 1.99 cm/kyr and correspond well to sediment accumulation rates in similar settings. We further discuss chronostratigraphic implications of our data.

A dromaeosaur from the Maastrichtian of James Ross Island and the Late Cretaceous Antarctic dinosaur fauna

USGS Publications Warehouse

Case, Judd A.; Martin, James E.; Reguero, Marcelo

2007-01-01

The recovery of material of a small theropod from the Early Maastrichtian, Cape Lamb Member of the Snow Hill Island Formation is an unusual occurrence from primarily marine sediments. The pedal morphology of the specimen that includes a Metatarsal II with a lateral expansion caudal to Metatarsal III, a third metatarsal that is proximally narrow and distally wide, a Metatarsal III with a distal end that is incipiently ginglymoidal and a second pedal digit with sickle-like ungual are all diagnostic of a theropod that belongs to the family of predatory dinosaurs, the Dromaeosauridae. Yet this Antarctic dromaeosaur retains plesiomorphic features in its ankle and foot morphology. As new dromaeosaur species are being recovered from the mid-Cretaceous of South America and the retention of primitive characters in the Antarctic dromaeosaur, a new biogeographic hypothesis on dromaeosaur distribution has been generated. Gondwanan dromaeosaurs are not North America immigrants into South America and Antarctica; rather they are the relicts of a cosmopolitan dromaeosaur distribution, which has been separated by the vicariant break up of Pangea and created an endemic clade of dromaeosaurs in Gondwana.

Petroleum source-rock potentials of the cretaceous transgressive-regressive sedimentary sequences of the Cauvery Basin

NASA Astrophysics Data System (ADS)

Chandra, Kuldeep; Philip, P. C.; Sridharan, P.; Chopra, V. S.; Rao, Brahmaji; Saha, P. K.

The present work is an attempt to contribute to knowledge on the petroleum source-rock potentials of the marine claystones and shales of basins associated with passive continental margins where the source-rock developments are known to have been associated with the anoxic events in the Mesozoic era. Data on three key exploratory wells from three major depressions Ariyallur-Pondicherry, Thanjavur and Nagapattinam of the Cauvery Basin are described and discussed. The average total organic carbon contents of the transgressive Pre-Albian-Cinomanian and Coniacian/Santonian claystones/shales range from 1.44 and 1.16%, respectively. The transgressive/regressive Campanian/Maastrichtian claystones contain average total organic carbon varying from 0.62 to 1.19%. The kerogens in all the studied stratigraphic sequences are classified as type-III with Rock-Eval hydrogen indices varying from 30 to 275. The nearness of land masses to the depositional basin and the mainly clastic sedimentation resulted in accumulation and preservation of dominantly type-III kerogens. The Pre-Albian to Cinomanian sequences of peak transgressive zone deposited in deep marine environments have kerogens with a relatively greater proportion of type-II components with likely greater contribution of planktonic organic matters. The global anoxic event associated with the Albian-Cinomanian marine transgression, like in many other parts of the world, has pervaded the Cauvery Basin and favoured development of good source-rocks with type-III kerogens. The Coniacian-Campanian-Maastrichtian transgressive/regressive phase is identified to be relatively of lesser significance for development of good quality source-rocks.

Biomolecular characterization and protein sequences of the Campanian hadrosaur B. canadensis.

PubMed

Schweitzer, Mary H; Zheng, Wenxia; Organ, Chris L; Avci, Recep; Suo, Zhiyong; Freimark, Lisa M; Lebleu, Valerie S; Duncan, Michael B; Vander Heiden, Matthew G; Neveu, John M; Lane, William S; Cottrell, John S; Horner, John R; Cantley, Lewis C; Kalluri, Raghu; Asara, John M

2009-05-01

Molecular preservation in non-avian dinosaurs is controversial. We present multiple lines of evidence that endogenous proteinaceous material is preserved in bone fragments and soft tissues from an 80-million-year-old Campanian hadrosaur, Brachylophosaurus canadensis [Museum of the Rockies (MOR) 2598]. Microstructural and immunological data are consistent with preservation of multiple bone matrix and vessel proteins, and phylogenetic analyses of Brachylophosaurus collagen sequenced by mass spectrometry robustly support the bird-dinosaur clade, consistent with an endogenous source for these collagen peptides. These data complement earlier results from Tyrannosaurus rex (MOR 1125) and confirm that molecular preservation in Cretaceous dinosaurs is not a unique event.

Supplementary cranial description of the types of Edmontosaurus regalis (Ornithischia: Hadrosauridae), with comments on the phylogenetics and biogeography of Hadrosaurinae

PubMed Central

Mallon, Jordan C.; Currie, Margaret L.

2017-01-01

The cranial anatomy of the flat-skulled hadrosaurine Edmontosaurus regalis (Ornithischia: Hadrosauridae) is extensively described here, based on the holotype and paratype collected from the middle part of the Horseshoe Canyon Formation in southern Alberta. Focus is given to previously undocumented features of ontogenetic and phylogenetic importance. This description facilitates overall osteological comparisons between E. regalis and other hadrosaurids (especially E. annectens), and revises the diagnosis of E. regalis, to which a new autapomorphy (the dorsal half of the jugal anterior process bearing a sharp posterolateral projection into the orbit) is added. We consider the recently named Ugrunaaluk kuukpikensis from the upper Campanian/lower Maastrichtian of Alaska a nomen dubium, and conservatively regard the Alaskan material as belonging to Edmontosaurus sp.. A phylogenetic analysis of Hadrosauroidea using maximum parsimony further corroborates the sister-taxon relationship between E. regalis and E. annectens. In the strict consensus tree, Hadrosaurus foulkii occurs firmly within the clade comprising all non-lambeosaurine hadrosaurids, supporting the taxonomic scheme that divides Hadrosauridae into Hadrosaurinae and Lambeosaurinae. Within Edmontosaurini, Kerberosaurus is posited as the sister taxon to the clade of Shantungosaurus + Edmontosaurus. The biogeographic reconstruction of Hadrosaurinae in light of the time-calibrated cladogram and probability calculation of ancestral areas for all internal nodes reveals a significantly high probability for the North American origin of the clade. However, the Laramidia–Appalachia dispersals around the Santonian–Campanian boundary, inferred from the biogeographic scenario for the North American origin of Hadrosaurinae, are in conflict with currently accepted paleogeographic models. By contrast, the Asian origin of Hadrosaurinae with its relatively low probability resulting from the biogeographic analysis is worth

Tectonic controls on the genesis of ignimbrites from the Campanian Volcanic Zone, southern Italy

USGS Publications Warehouse

Rolandi, G.; Bellucci, F.; Heizler, M.T.; Belkin, H.E.; de Vivo, B.

2003-01-01

The Campanian Plain is an 80 x 30 km region of southern Italy, bordered by the Apennine Chain, that has experienced subsidence during the Quaternary. This region, volcanologically active in the last 600 ka, has been identified as the Campanian Volcanic Zone (CVZ). The products of three periods of trachytic ignimbrite volcanism (289-246 ka, 157 ka and 106 ka) have been identified in the Apennine area in the last 300 ka. These deposits probably represent distal ash flow units of ignimbrite eruptions which occurred throughout the CVZ. The resulting deposits are interstratified with marine sediments indicating that periods of repeated volcano-tectonic emergence and subsidence may have occurred in the past. The eruption, defined as the Campanian Ignimbrite (CI), with the largest volume (310 km3), occurred in the CVZ 39 ka ago. The products of the CI eruption consist of two units (unit-1 and unit-2) formed from a single compositionally zoned magma body. Slightly different in composition, three trachytic melts constitute the two units. Unit-1 type A is an acid trachyte, type B is a trachyte and type C of unit-2 is a mafic trachyte. The CI, vented from pre-existing neotectonic faults, formed during the Apennine uplift, Initially the venting of volatile-rich type A magma deposited the products to the N-NE of the CVZ. During the eruption, the Acerra graben already affected by a NE-SW fault system, was transected by E-W faults, forming a cross-graben that extended to the gulf of Naples. E-W faults were then further dislocated by NE-SW transcurrent movements. This additional collapse significantly influenced the deposition of the B-type magma of unit-1, and the C-type magma of unit-2 toward the E-SE and S, in the Bay of Naples. The pumice fall deposit underlying the CI deposits, until now thought to be associated with the CI eruption, is not a strict transition from plinian to CI-forming activity. It is derived instead from an independent source probably located near the

Upper Albian-Maastrichtian calcareous plankton biostratigraphy, magnetostratigraphy and carbon isotope stratigraphy of the classical Tethyan Gubbio section (Italy)

NASA Astrophysics Data System (ADS)

Premoli Silva, Isabella; Coccioni, Rodolfo; Sabatino, Nadia; Sprovieri, Mario; Voigt, Silke

2014-05-01

The Tethyan pelagic sections at Bottaccione and Contessa Highway (Gubbio, central Italy) are internationally recognized to be the standard reference sections for the Late Cretaceous to Eocene geomagnetic polarity time scale calibrated to the integrated planktonic foraminiferal and calcareous nannofossil biostratigraphy. Due to the presence of a gap within Chron C31n in the Bottaccione section, we use two distinct portions of these sections to construct an upper Albian-Maastrichtian complete and well-preserved composite stratigraphic record, 333.1 m in thickness and ~37 Myr in duration. A refined magnetostratigraphy and planktonic foraminiferal and calcareous nannofossil biostratigraphy is here presented for this stratigraphic succession. In particular, the recovery of planktonic foraminifera successfully disaggregated from the hard lithologies allows to place more precisely several bioevents that include the lowest occurrence (LO) of Thalmanninella globotruncanoides defining the Albian/Cenomanian boundary, the LO of Globotruncana linneiana that approximates the base of the Santonian, the LO of Globotruncana aegyptiaca occurring earlier than previously recognized, the LO of Pseudoguembelina palpebra, and, in addition, the well-constrained and complete pattern of the evolutionary origin of Racemiguembelina fructicosa from Pseudotextularia elegans through Pseudotextularia intermedia and Racemiguembelina powelli previously undetected. Moreover, the highest occurrence of Gansserina gansseri and the LO of Plummerita hantkeninoides allow to subdivide the latest Maastrichtian into the Pseudoguembelina hariaensis, Pseudotextularia elegans and Plummerita hantkeninoides planktonic foraminiferal Zones. The refined magnetobiostratigraphic framework may improve reliability of Late Cretaceous correlations at low to middle latitude as well as paleoenvironmental, paleoclimatic and paleoceanographic interpretations. Finally, an almost complete, high-resolution carbon isotope curve

Marine reptiles from the Late Cretaceous of northern Patagonia

NASA Astrophysics Data System (ADS)

Gasparini, Z.; Casadio, S.; Fernández, M.; Salgado, L.

2001-04-01

During the Campanian-Maastrichtian, Patagonia was flooded by the Atlantic and reduced to an archipelago. Several localities of northern Patagonia have yielded marine reptiles. Analysis of several assemblages suggests that the diversity and abundance of pelagic marine reptiles in northern Patagonia was higher by the end of the Cretaceous than previously thought. Several plesiosaurids, including Aristonectes parvidens and the polycotylid Sulcusuchus, and the first remains of mosasaurinae have been found. The Cretaceous marine reptile record from South America is scanty. Nevertheless, materials described here suggest that Tethyan and Weddelian forms converged in northern Patagonia, as seen with invertebrates.

Paleo­geographic implications of molluscan assemblages in the Upper Cretaceous (Campanian) Pigeon Point Formation, California

USGS Publications Warehouse

Elder, William P.; Saul, LouElla

1993-01-01

The Pigeon Point Formation crops out along the San Mateo County coastline in a northern and southern sequence of folded and faulted strata. Correlation of the two sequences remains somewhat equivocal, although on the basis of biostratigraphy and a reversed magnetic interval both appear to have been deposited during the early to middle Campanian. Sedimentary structures suggest that the northern sequence was deposited by turbidity currents in a continental rise setting, whereas the southern sequence primarily reflects deposition in shelf and slope environments . Right-lateral offset on the San Andreas and subsidiary faults to the east of the Pigeon Point Formation can account for 100's of km of northward transport since its deposition. However, Champion and others (1984) suggested 2500 km of northward transport from a tropical setting of about 21°N. Molluscan assemblages in the formation argue strongly for a less tropical site of deposition. Relative abundances of warm and temperate taxa and the presence or absence of key species are similar to those of the Santa Ana Mountains Cretaceous section, and are indicative of a war

Performance assessment of FY-3C/MERSI on early orbit

NASA Astrophysics Data System (ADS)

Hu, Xiuqing; Xu, Na; Wu, Ronghua; Chen, Lin; Min, Min; Wang, Ling; Xu, Hanlie; Sun, Ling; Yang, Zhongdong; Zhang, Peng

2014-11-01

FY-3C/MERSI has some remarkable improvements compared to the previous MERSIs including better spectral response function (SRF) consistency of different detectors within one band, increasing the capability of lunar observation by space view (SV) and the improvement of radiometric response stability of solar bands. During the In-orbit verification (IOV) commissioning phase, early results that indicate the MERSI representative performance were derived, including the signal noise ratio (SNR), dynamic range, MTF, B2B registration, calibration bias and instrument stability. The SNRs at the solar bands (Bands 1-4 and 6-20) was largely beyond the specifications except for two NIR bands. The in-flight calibration and verification for these bands are also heavily relied on the vicarious techniques such as China radiometric calibration sites(CRCS), cross-calibration, lunar calibration, DCC calibration, stability monitoring using Pseudo Invariant Calibration Sites (PICS) and multi-site radiance simulation. This paper will give the results of the above several calibration methods and monitoring the instrument degradation in early on-orbit time.

North American nonmarine climates and vegetation during the Late Cretaceous

USGS Publications Warehouse

Wolfe, J.A.; Upchurch, G.R.

1987-01-01

Analyses of physiognomy of Late Cretaceous leaf assemblages and of structural adaptations of Late Cretaceous dicotyledonous woods indicate that megathermal vegetation was an open-canopy, broad-leaved evergreen woodland that existed under low to moderate amounts of rainfall evenly distributed through the year, with a moderate increase at about 40-45??N. Many dicotyledons were probably large, massive trees, but the tallest trees were evergreen conifers. Megathermal climate extended up to paleolatitude 45-50??N. Mesothermal vegetation was at least partially an open, broad-leaved evergreen woodland (perhaps a mosaic of woodland and forest), but the evapotranspirational stress was less than in megathermal climate. Some dicotyledons were large trees, but most were shrubs or small trees; evergreen conifers were the major tree element. Some mild seasonality is evidenced in mesothermal woods; precipitational levels probably varied markedly from year to year. Northward of approximately paleolatitude 65??N, evergreen vegetation was replaced by predominantly deciduous vegetation. This replacement is presumably related primarily to seasonality of light. The southern part of the deciduous vegetation probably existed under mesothermal climate. Comparisons to leaf and wood assemblages from other continents are generally consistent with the vegetational-climatic patterns suggested from North American data. Limited data from equatorial regions suggest low rainfall. Late Cretaceous climates, except probably those of the Cenomanian, had only moderate change through time. Temperatures generally appear to have warmed into the Santonian, cooled slightly into the Campanian and more markedly into the Maastrichtian, and then returned to Santonian values by the late Maastrichtian. The early Eocene was probably warmer than any period of the Late Cretaceous. Latitudinal temperature gradients were lower than at present. For the Campanian and Maastrichtian, a gradient of about 0.3??C/1

Time scale controversy: Accurate orbital calibration of the early Paleogene

NASA Astrophysics Data System (ADS)

Roehl, U.; Westerhold, T.; Laskar, J.

2012-12-01

Timing is crucial to understanding the causes and consequences of events in Earth history. The calibration of geological time relies heavily on the accuracy of radioisotopic and astronomical dating. Uncertainties in the computations of Earth's orbital parameters and in radioisotopic dating have hampered the construction of a reliable astronomically calibrated time scale beyond 40 Ma. Attempts to construct a robust astronomically tuned time scale for the early Paleogene by integrating radioisotopic and astronomical dating are only partially consistent. Here, using the new La2010 and La2011 orbital solutions, we present the first accurate astronomically calibrated time scale for the early Paleogene (47-65 Ma) uniquely based on astronomical tuning and thus independent of the radioisotopic determination of the Fish Canyon standard. Comparison with geological data confirms the stability of the new La2011 solution back to 54 Ma. Subsequent anchoring of floating chronologies to the La2011 solution using the very long eccentricity nodes provides an absolute age of 55.530 ± 0.05 Ma for the onset of the Paleocene/Eocene Thermal Maximum (PETM), 54.850 ± 0.05 Ma for the early Eocene ash -17, and 65.250 ± 0.06 Ma for the K/Pg boundary. The new astrochronology presented here indicates that the intercalibration and synchronization of U/Pb and 40Ar/39Ar radioisotopic geochronology is much more challenging than previously thought.

Time scale controversy: Accurate orbital calibration of the early Paleogene

NASA Astrophysics Data System (ADS)

Westerhold, Thomas; RöHl, Ursula; Laskar, Jacques

2012-06-01

Timing is crucial to understanding the causes and consequences of events in Earth history. The calibration of geological time relies heavily on the accuracy of radioisotopic and astronomical dating. Uncertainties in the computations of Earth's orbital parameters and in radioisotopic dating have hampered the construction of a reliable astronomically calibrated time scale beyond 40 Ma. Attempts to construct a robust astronomically tuned time scale for the early Paleogene by integrating radioisotopic and astronomical dating are only partially consistent. Here, using the new La2010 and La2011 orbital solutions, we present the first accurate astronomically calibrated time scale for the early Paleogene (47-65 Ma) uniquely based on astronomical tuning and thus independent of the radioisotopic determination of the Fish Canyon standard. Comparison with geological data confirms the stability of the new La2011 solution back to ˜54 Ma. Subsequent anchoring of floating chronologies to the La2011 solution using the very long eccentricity nodes provides an absolute age of 55.530 ± 0.05 Ma for the onset of the Paleocene/Eocene Thermal Maximum (PETM), 54.850 ± 0.05 Ma for the early Eocene ash -17, and 65.250 ± 0.06 Ma for the K/Pg boundary. The new astrochronology presented here indicates that the intercalibration and synchronization of U/Pb and 40Ar/39Ar radioisotopic geochronology is much more challenging than previously thought.

Sequence stratigraphy of the Maastrichtian-Paleocene succession at the Dakhla Oasis, Western Desert, Egypt

NASA Astrophysics Data System (ADS)

Hewaidy, Abdel Galil A.; Farouk, Sherif; Bazeen, Youssef S.

2017-12-01

The Maastrichtian-Paleocene succession at the Dakhla Oasis is marked by the presence of a typical Nile Valley Facies represented by the Dakhla and Tarawan formations in Edmonstone and Qur El Malik sections in the central and western parts of the oasis, while a mixed Nile Valley and Garra Al-Arbain facies represented by Dakhla, Kurkur and Tarawan formations in Teneida section in the eastern part of the oasis adjacent to the Abu Tartur Plateau. These sections were examined for their foraminiferal contents, lithologic characters and stratigraphic boundaries. The distribution of foraminifera in the studied sections is variable and inconstant, as the planktonics are concentrated only at certain levels, which may be considered as a time intervals of transgression and maximum flooding surfaces. Eight planktonic biozones are distinguished in this work; of theses two are of Maastrichtain age and six are of Paleocene age. Eight 3rd order depositional sequences are recognized in the studied Maastrichtian-Paleocene succession based on the time stratigraphic boundaries released from the planktonic foraminifera and sea level changes which are released from the paleoecologic interpretations. The distinguished sequences are subdivided into their systems tracts based on the paleobathymetric interpretations of P/B% and benthic biofacies analysis. These sequences are bounded by eight sequence boundaries (SB A - SB H) represented by unconformity surfaces and depositional hiatuses. The correlation of the sequence boundaries of the established depositional sequences with the eustatic sea level curve, suggesting that these depositional sequences were resulted from the interplay of eustatic sea-level changes and local tectonic activities.

Submillimeter Wave Astronomy Satellite (SWAS) Launch and Early Orbit Support Experiences

NASA Technical Reports Server (NTRS)

Kirschner, S.; Sedlak, J.; Challa, M.; Nicholson, A.; Sande, C.; Rohrbaugh, D.

1999-01-01

The Submillimeter Wave Astronomy Satellite (SWAS) was successfully launched on December 6, 1998 at 00:58 UTC. The two year mission is the fourth in the series of Small Explorer (SMEX) missions. SWAS is dedicated to the study of star formation and interstellar chemistry. SWAS was injected into a 635 km by 650 km orbit with an inclination of nearly 70 deg by an Orbital Sciences Corporation Pegasus XL launch vehicle. The Flight Dynamics attitude and navigation teams supported all phases of the early mission. This support included orbit determination, attitude determination, real-time monitoring, and sensor calibration. This paper reports the main results and lessons learned concerning navigation, support software, star tracker performance, magnetometer and gyroscope calibrations, and anomaly resolution. This includes information on spacecraft tip-off rates, first-day navigation problems, target acquisition anomalies, star tracker anomalies, and significant sensor improvements due to calibration efforts.

Evidence for global cooling in the Late Cretaceous

PubMed Central

Linnert, Christian; Robinson, Stuart A.; Lees, Jackie A.; Bown, Paul R.; Pérez-Rodríguez, Irene; Petrizzo, Maria Rose; Falzoni, Francesca; Littler, Kate; Arz, José Antonio; Russell, Ernest E.

2014-01-01

The Late Cretaceous ‘greenhouse’ world witnessed a transition from one of the warmest climates of the past 140 million years to cooler conditions, yet still without significant continental ice. Low-latitude sea surface temperature (SST) records are a vital piece of evidence required to unravel the cause of Late Cretaceous cooling, but high-quality data remain illusive. Here, using an organic geochemical palaeothermometer (TEX86), we present a record of SSTs for the Campanian–Maastrichtian interval (~83–66 Ma) from hemipelagic sediments deposited on the western North Atlantic shelf. Our record reveals that the North Atlantic at 35 °N was relatively warm in the earliest Campanian, with maximum SSTs of ~35 °C, but experienced significant cooling (~7 °C) after this to <~28 °C during the Maastrichtian. The overall stratigraphic trend is remarkably similar to records of high-latitude SSTs and bottom-water temperatures, suggesting that the cooling pattern was global rather than regional and, therefore, driven predominantly by declining atmospheric pCO2 levels. PMID:24937202

Test plan. Task 5, subtask 5.2: Early on-orbit TPSdebris impact tests

NASA Technical Reports Server (NTRS)

Greenberg, H. S.

1994-01-01

The limitation of damage to, and survival of, the cryogenic tankage during the on-orbit stay despite potential impact of orbital debris, may be a significant discriminator in the RHCTS trade studies described in the TA-1 trade study plan (ref. RHCTS-TSP-1) dated July 29, 1994. The objective of this early phase of an overall debris impact test program is to provide the data to support assessment of the relative suitability of integral and non integral tanks.

A New Centrosaurine Ceratopsid, Machairoceratops cronusi gen et sp. nov., from the Upper Sand Member of the Wahweap Formation (Middle Campanian), Southern Utah.

PubMed

Lund, Eric K; O'Connor, Patrick M; Loewen, Mark A; Jinnah, Zubair A

2016-01-01

The Upper Cretaceous (middle-late Campanian) Wahweap Formation of southern Utah contains the oldest diagnostic evidence of ceratopsids (to date, all centrosaurines) in North America, with a number of specimens recovered from throughout a unit that spans between 81 and 77 Ma. Only a single specimen has been formally named, Diabloceratops eatoni, from the lower middle member of the formation. Machairoceratops cronusi gen. et sp. nov., a new centrosaurine ceratopsid from the upper member of the Wahweap Formation, is here described based on cranial material representing a single individual recovered from a calcareous mudstone. The specimen consists of two curved and elongate orbital horncores, a left jugal, a nearly complete, slightly deformed braincase, the left squamosal, and a mostly complete parietal ornamented by posteriorly projected, anterodorsally curved, elongate spikes on either side of a midline embayment. The fan-shaped, stepped-squamosal is diagnostic of Centrosaurinae, however, this element differs from the rectangular squamosal in Diabloceratops. Machairoceratops also differs in the possession of two anterodorsally (rather than laterally) curved epiparietal ornamentations on either side of a midline embayment that are distinguished by a posteromedially-oriented sulcus along the entire length of the epiparietal. Additionally, the parietosquamosal frill is lacking any other epiossifications along its periphery. Machairoceratops shares a triangular (rather than round) frill and spike-like epiparietal loci (p1) ornamentation with the stratigraphically lower Diabloceratops. Both parsimony and Bayesian phylogenetic analyses place Machairoceratops as an early-branching centrosaurine. However, the parsimony-based analysis provides little resolution for the position of the new taxon, placing it in an unresolved polytomy with Diabloceratops. The resultant Bayesian topology yielded better resolution, aligning Machairoceratops as the definitive sister taxon to a

Stratigraphy of Upper Cretaceous and Cenozoic deposits of the Bakchar iron ore deposit (southwestern Siberia): New data

NASA Astrophysics Data System (ADS)

Lebedeva, N. K.; Kuzmina, O. B.; Sobolev, E. S.; Khazina, I. V.

2017-01-01

The results of complex palynological and microfaunistic studies of Upper Cretaceous and Cenozoic deposits of the Bakchar iron ore deposit are presented. Geochronologically, the age of the deposits varies from Campanian to Quaternary. It was established that the Slavgorod, Gan'kino, and Jurki (?) formations contain four biostratons in the rank of beds with dinocysts and three biostratons in the rank of beds with spores and pollen. The Cenozoic continental deposits contain four biostratons in the rank of beds, containing spores and pollen. As a result of the study, a large stratigraphic gap in the Cretaceous-Paleogene boundary deposits, covering a significant part of the Maastrichtian, Paleocene, Ypresian, and Lutetian stages of the Eocene, was established. The remnants of a new morphotype of heteromorphic ammonites of genus Baculites were first described in deposits of the Slavgorod Formation (preliminarily, upper Campanian). The distribution features of the different palynomorph groups in the Upper Cretaceous-Cenozoic deposits in the area of study due to transgressive-regressive cycles and climate fluctuations were revealed.

Early Paleogene Orbital Variations in Atmospheric CO2 and New Astronomical Solutions

NASA Astrophysics Data System (ADS)

Zeebe, R. E.

2017-12-01

Geologic records across the globe show prominent variations on orbital time scales during numerous epochs going back hundreds of millions of years. The origin of the Milankovic cycles are variations in orbital parameters of the bodies of the Solar System. On long time scales, the orbital variations can not be computed analytically because of the chaotic nature of the Solar System. Thus, numerical solutions are used to estimate changes in, e.g., Earth's orbital parameters in the past. The orbital solutions represent the backbone of cyclostratigraphy and astrochronology, now widely used in geology and paleoclimatology. Hitherto only two solutions for Earth's eccentricity appear to be used in paleoclimate studies, provided by two different groups that integrated the full Solar System equations over the past >100 Myr. In this presentation, I will touch on the basic physics behind, and present new results of, accurate Solar System integrations for Earth's eccentricity over the past hundred million years. I will discuss various limitations within the framework of the present simulations and compare the results to existing solutions. Furthermore, I will present new results from practical applications of such orbital solutions, including effects of orbital forcing on coupled climate- and carbon cycle variations. For instance, we have recently revealed a mechanism for a large lag between changes in carbon isotope ratios and eccentricity at the 400-kyr period, which has been observed in Paleocene, Oligocene, and Miocene sections. Finally, I will present the first estimates of orbital-scale variations in atmospheric CO2 during the early Paleogene.

The benthic macrofauna from the Lower Maastrichtian chalk of Kronsmoor (northern Germany, Saturn quarry): taxonomic outline and palaeoecologic implications

NASA Astrophysics Data System (ADS)

Engelke, Julia; Esser, Klaus J. K.; Linnert, Christian; Mutterlose, Jörg; Wilmsen, Markus

2016-12-01

The benthic macroinvertebrates of the Lower Maastrichtian chalk of Saturn quarry at Kronsmoor (northern Germany) have been studied taxonomically based on more than 1,000 specimens. Two successive benthic macrofossil assemblages were recognised: the lower interval in the upper part of the Kronsmoor Formation (Belemnella obtusa Zone) is characterized by low abundances of macroinvertebrates while the upper interval in the uppermost Kronsmoor and lowermost Hemmoor formations (lower to middle Belemnella sumensis Zone) shows a high macroinvertebrate abundance (eight times more than in the B. obtusa Zone) and a conspicuous dominance of brachiopods. The palaeoecological analysis of these two assemblages indicates the presence of eight different guilds, of which epifaunal suspension feeders (fixo-sessile and libero-sessile guilds), comprising approximately half of the trophic nucleus of the lower interval, increased to a dominant 86% in the upper interval, including a considerable proportion of rhynchonelliform brachiopods. It is tempting to relate this shift from the lower to the upper interval to an increase in nutrient supply and/or a shallowing of the depositional environment but further data including geochemical proxies are needed to fully understand the macrofossil distribution patterns in the Lower Maastrichtian of Kronsmoor.

The sensitivity of harassment to orbit: mass loss from early-type dwarfs in galaxy clusters

NASA Astrophysics Data System (ADS)

Smith, R.; Sánchez-Janssen, R.; Beasley, M. A.; Candlish, G. N.; Gibson, B. K.; Puzia, T. H.; Janz, J.; Knebe, A.; Aguerri, J. A. L.; Lisker, T.; Hensler, G.; Fellhauer, M.; Ferrarese, L.; Yi, S. K.

2015-12-01

We conduct a comprehensive numerical study of the orbital dependence of harassment on early-type dwarfs consisting of 168 different orbits within a realistic, Virgo-like cluster, varying in eccentricity and pericentre distance. We find harassment is only effective at stripping stars or truncating their stellar discs for orbits that enter deep into the cluster core. Comparing to the orbital distribution in cosmological simulations, we find that the majority of the orbits (more than three quarters) result in no stellar mass loss. We also study the effects on the radial profiles of the globular cluster systems of early-type dwarfs. We find these are significantly altered only if harassment is very strong. This suggests that perhaps most early-type dwarfs in clusters such as Virgo have not suffered any tidal stripping of stars or globular clusters due to harassment, as these components are safely embedded deep within their dark matter halo. We demonstrate that this result is actually consistent with an earlier study of harassment of dwarf galaxies, despite the apparent contradiction. Those few dwarf models that do suffer stellar stripping are found out to the virial radius of the cluster at redshift = 0, which mixes them in with less strongly harassed galaxies. However when placed on phase-space diagrams, strongly harassed galaxies are found offset to lower velocities compared to weakly harassed galaxies. This remains true in a cosmological simulation, even when haloes have a wide range of masses and concentrations. Thus phase-space diagrams may be a useful tool for determining the relative likelihood that galaxies have been strongly or weakly harassed.

Natural fluoride levels in some springs and streams from the late Maastrichtian Ajali formation in Ohafia-Arochukwu area of south eastern Nigeria.

PubMed

Ibe, K K; Adlegbembo, A O; Mafeni, J O; Danfillo, I S

1999-09-01

The aim of this study was to provide baseline data on the fluoride levels in waters associated with the late Maastrichtian Ajali formation in Ohafia-Arochukwu area of South Eastern Nigeria. Water samples from 14 artesian, perched springs and eight streams from the formation were collected with plastic containers. Fluoride analysis was carried out with inductively coupled plasma Atomic Emission Spectrometry (ICP-AES) equipment at the laboratories of the Department of Earth Science, University of Leeds, United Kingdom. The results showed that fluoride occurred in only one of the 14 spring water samples. Fluoride level in the sample was 0.03 ppm. The spring water, which contained some fluoride, was possibly associated with another rock formation: namely, the limestone bearing Nsukka formation, which overlies the Ajali formation. No fluoride was observed in all the stream water samples. This study reported the absence of fluoride in spring and stream waters associated with the late Maastrichtian formations in Nigeria.

Tectonic events reflected by palaeocurrents, zircon geochronology, and palaeobotany in the Sierra Baguales of Chilean Patagonia

NASA Astrophysics Data System (ADS)

Gutiérrez, Nestor M.; Le Roux, Jacobus P.; Vásquez, Ana; Carreño, Catalina; Pedroza, Viviana; Araos, José; Oyarzún, José Luis; Pablo Pino, J.; Rivera, Huber A.; Hinojosa, L. F.

2017-01-01

The Sierra Baguales, situated north of the Torres Del Paine National Park in the Magallanes region of southern Chile, shows a well-exposed stratigraphic sequence ranging from the Late Cretaceous to late Pliocene, which presents a unique opportunity to study the evolution of sedimentological styles and trends, palaeoclimate changes, and tectonic events during this period. The depositional environment changed from a continental slope and shelf during the Cenomanian-Campanian (Tres Pasos Formation) to deltaic between the Campanian-Maastrichtian (Dorotea Formation) and estuarine in the Lutetian-Bartonian (Man Aike Formation). During the Rupelian, a continental environment with meandering rivers and overbank marshes was established (Río Leona Formation). This area was flooded in the early Burdigalian (Estancia 25 de Mayo Formation) during the Patagonian Transgression, but emerged again during the late Burdigalian (Santa Cruz Formation). Measured palaeocurrent directions in this Mesozoic-Cenozoic succession indicate source areas situated between the northeast and east-southeast during the Late Cretaceous, east-southeast during the middle Eocene, and southwest during the early Oligocene to early Miocene. This is confirmed by detrital zircon age populations in the different units, which can be linked to probable sources of similar ages in these areas. The east-southeastern provenance is here identified as the Antarctic Peninsula or its northeastern extension, which is postulated to have been attached to Fuegian Patagonia during the Eocene. The southwestern and western sources were exhumed during gradual uplift of the Southern Patagonian Andes, coinciding with a change from marine to continental conditions in the Magallanes-Austral Basin, as well as a decrease in mean annual temperature and precipitation indicated by fossil leaves in the Río Leona Formation. The rain shadow to the east of the Andes thus started to develop here during the late Eocene-early Oligocene ( 34

Detrital K-feldspar thermochronology of the Nanaimo Group: Characterization of Basement and Extraregional Basin Contributions

NASA Astrophysics Data System (ADS)

Isava, V.; Grove, M.; Mahoney, J. B.; Kimbrough, D. L.

2016-12-01

The Late Cretaceous-Early Paleogene Nanaimo Group covers the contact between Triassic basement Wrangellia terrane and the Jurassic-Cretaceous Coast Plutonic Complex (CPC) in southern British Columbia. Prior detrital zircon U-Pb and Hf studies indicate a change in sediment source for the Nanaimo basin, from the primitive CPC in Santonian-Early Campanian time to an isotopically evolved continental extraregional source during the late Campanian/Maastrictian. Two notably different areas have been proposed as potential source regions: (1) the Idaho/Boulder batholith and Belt Supergroup, and (2) the Mojave/Salinia segment of structurally disrupted late Cretaceous southern California margin. Single crystal 40Ar/39Ar laser fusion of ca. 100-200 grains apiece from seven detrital K-feldspar samples from Santonian-Maastrichtian strata of the northern Nanaimo Group constrain the history of the sediments' source regions. The two oldest samples, from the K-feldspar poor Comox and Extension Fms., display a monotonic increasing distribution of cooling ages 80-125 Ma that reflects shallow erosion of the CPC. In contrast, Late Campanian strata of the Cedar District and De Courcy Fms. exhibit a more pronounced cluster of cooling ages 80-95 Ma as well as a greater proportion of Jurassic ages that represent progressively deeper erosion of the CPC. Evidence for an extraregional sediment source appears abruptly in the Geoffrey Fm. by 72 Ma, matching the time of local-to-extraregional shift indicated in detrital zircon U-Pb studies. Over 90% of the detrital K-feldspars from these arkosic sandstones yield cooling ages of 70-80 Ma, with sparse older ages associated with the CPC. Samples from the successively younger Spray and Gabriola Fms. also yield >90% K-feldspar ages younger than 80 Ma and exhibit age maxima of 68 Ma and 65 Ma, respectively. These results are distinct from detrital zircon U-Pb and K-feldspar 40Ar/39Ar ages of the southern Sierra Nevada, Mojave/Salina, and northern

Towards Time-Scaling of Mixing for the Campanian Ignimbrite: Systemic Variation in Sr-Isotopic Composition from Mixing Experiments

NASA Astrophysics Data System (ADS)

de Campos, Cristina; Civetta, Lucia; Perugini, Diego; Dingwell, Donald B.

2010-05-01

Eruptions in the Campi Flegrei caldera, the most dangerous volcanic setting in Europe, are thought to be triggered by short-term pre-eruptive mixing of trachytic to trachydacitic resident and new basaltic, trachyandesitic (=shoshonitic) magma, in shallow magma chambers (e. g. Arienzo et al, 2008, Bull. Volcanol.). Previous geochemical and volcanological data on the Campanian Ignimbrite, (>150 km3, 39 Ma), in Campi Flegrei, point towards a layered reservoir, which evolved from the replenishment of the magma chamber with shoshonitic magma and short-term pre-eruptive mixing between a trachytic and a phonolitic trachytic magma. With the purpose to experimentally study the mobility and homogenization of Rb-Sr isotopes in this system, we performed mixing experiments using natural phonolitic trachytic (end-member A - S. Nicola type) and trachytic (end-member B - Mondragone-type) samples, representing the two end-members involved in the origin of the Campanian Ignimbrite. Resultant glasses from a time series, ranging from 1-hour up to 1-week, under constant flow velocity (0.5 rotations per minute; after De Campos et al., 2008. Chem. Geol.), have been analysed with respect to the Rb- and Sr-systematics. Our results reveal a progressive homogenization of the contrasting Sr-isotopes towards a hybrid value. With increasing experimental duration a clear decrease in the standard deviation of isotopic ratios has been observed, reflecting progressive isotopic homogenization. Our results also support the effectiveness of mixing in the Campi Flegrei reservoirs, in liquidus, under high temperature, before the onset of fractional crystallization. Since different eruptive events from Campi Flegrei can be well characterized by means of isotopic composition, the main goal for the present study will be to use experimental data and numerical modeling in order to estimate time scales of mixing associated with the eruption of the Campanian Ignimbrite, and then compare them to the several

The formation conditions of the burial site of Late Cretaceous dinosaurs and plants in the Kakanaut River basin (Koryak Highlands, Northeastern Asia)

NASA Astrophysics Data System (ADS)

Shczepetov, S. V.; Herman, A. B.

2017-07-01

The stratigraphic position of layers containing plant and animal remains in the Koryak Highlands (Northeast Asia) is under discussion. Their age is defined as late Campanian-early Maastrichtian. Plant-bearing and bone-bearing rocks represent cemented basaltic tephra. The former contain a small amount of xenogenic material and slightly rounded volcaniclastic material, which indicates its insignificant transportation. Ash particles in bone-bearing rocks are even less rounded. Among them, there are no rock fragments of other composition. Large bones and their fragments, as xenoliths, are chaotically distributed in the rock matrix as if floating in mass of ash material. This burial site was probably formed in a continental environment as a result of the gravitational and eolian transportation of the terrigenous material. The burial of small dinosaur bones and teeth occurred during the deposition of a small stream of a semiliquid water-ash mixture. This work presents a possible mechanism of the formation of burial sites, taking into consideration proposed conditions of the life and reproduction of dinosaurs in the Late Mesozoic Arctic.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winn, R.D. Jr.; Steinmetz, J.C.; Kerekgyarto, W.L.

Lithological and compositional relationships, thicknesses, and palynological data from drilling cuttings from five wells in the Anza rift, Kenya, indicate active rifting during the Late Cretaceous and Eocene-Oligocene. The earlier rifting possibly started in the Santonian-Coniacian, primarily occurred in the Campanian, and probably extended into the Maastrichtian. Anza rift sedimentation was in lacustrine, lacustrine-deltaic, fluvial, and flood-basin environments. Inferred synrift intervals in wells are shalier, thicker, more compositionally immature, and more poorly sorted than Lower Cretaceous ( )-lower Upper Cretaceous and upper Oligocene( )-Miocene interrift deposits. Synrift sandstone is mostly feldspathic or arkosic wacke. Sandstone deposited in the Anza basinmore » during nonrift periods is mostly quartz arenite, and is coarser and has a high proportion of probable fluvial deposits relative to other facies. Volcanic debris is absent in sedimentary strata older than Pliocene-Holocene, although small Cretaceous intrusions are present in the basin. Cretaceous sandstone is cemented in places by laumontite, possibly recording Campanian extension. Early Cretaceous history of the Anza basin is poorly known because of the limited strata sampled; Jurassic units were not reached. Cretaceous rifting in the Anza basin was synchronous with rifting in Sudan and with the breakup and separation of South America and Africa; these events likely were related. Eocene-Oligocene extension in the Anza basin reflects different stresses. The transition from active rifting to passive subsidence in the Anza basin at the end of the Neogene, in turn, records a reconfigured response of east African plates to stresses and is correlated with formation of the East Africa rift.« less

A CHARACEAN THALLUS WITH ATTACHED GYROGONITES AND ASSOCIATED FOSSIL CHAROPHYTES FROM THE MAASTRICHTIAN OF THE EASTERN PYRENEES (CATALONIA, SPAIN)(1).

PubMed

Villalba-Breva, Sheila; Martín-Closas, Carles

2011-02-01

The new species Clavatoraxis microcharophorus is described from the Lower Maastrichtian of the Eastern Pyrenees (Catalonia, Spain). Microchara sp. gyrogonites were found in anatomical connection with this thallus, attached to bract-cell rosettes and coated by a structural tunica, formed by an expanded bract cell. This is a feature unknown in extant characeans, which only display lime incrustations similar to tunicae in extremely alkaline and well-illuminated environments. This is the first time that a complete fossil characean is described. The attribution of characean vegetative remains to the genus Clavatoraxis shows that this genus is not exclusive of clavatoraceans as previously thought. The taphonomic study of C. microcharophorus sp. nov. and associated fossil charophytes, along with sedimentological and microfacies analyses, has enabled us to characterize the habitat of this species in the Maastrichtian lake of Vallcebre. They grew forming meadows, and their remains were deposited in the poorly oxygenated lake bottom, where they were well preserved. A number of other characeans and porocharaceans were living in shallower belts. This was the case for Peckichara sp. and Munieria grambasti in the freshwater lacustrine meadows. Another species, Feistiella malladae, was found parautochthonous in brackish lakes. © 2011 Phycological Society of America.

Study of a homotopy continuation method for early orbit determination with the Tracking and Data Relay Satellite System (TDRSS)

NASA Technical Reports Server (NTRS)

Smith, R. L.; Huang, C.

1986-01-01

A recent mathematical technique for solving systems of equations is applied in a very general way to the orbit determination problem. The study of this technique, the homotopy continuation method, was motivated by the possible need to perform early orbit determination with the Tracking and Data Relay Satellite System (TDRSS), using range and Doppler tracking alone. Basically, a set of six tracking observations is continuously transformed from a set with known solution to the given set of observations with unknown solutions, and the corresponding orbit state vector is followed from the a priori estimate to the solutions. A numerical algorithm for following the state vector is developed and described in detail. Numerical examples using both real and simulated TDRSS tracking are given. A prototype early orbit determination algorithm for possible use in TDRSS orbit operations was extensively tested, and the results are described. Preliminary studies of two extensions of the method are discussed: generalization to a least-squares formulation and generalization to an exhaustive global method.

The CALorimetric Electron Telescope (CALET) Launch and Early On-Orbit Performance

NASA Astrophysics Data System (ADS)

Guzik, T. Gregory; Calet Collaboration

2016-03-01

The CALET space experiment, has been developed by collaborators in Japan, Italy and the United States, will study electrons to 20 TeV, gamma rays above 10 GeV and nuclei with Z =1 to 40 up to 1,000 TeV during a five-year mission on the International Space Station. The instrument consists of a particle charge identification module, a thin imaging calorimeter (3 r.l. in total) with tungsten plates interleaving scintillating fiber planes, and a thick calorimeter (27 r.l.) composed of lead tungstate logs. CALET has the depth, imaging capabilities and energy resolution for excellent separation between hadrons, electrons and gamma rays. The instrument was launched into orbit on August 19, 2015 and on August 25, 2015 was mounted as an attached payload on the International Space Station (ISS) Japanese Experiment Module - Exposed Facility (JEM-EF). The experiment has successfully completed on-orbit checkout and has now been transitioned to normal science operations. This presentation summarizes the instrument design, science goals and early on-orbit performance. This effort is supported by NASA in the United States, by JAXA in Japan, and ASI in Italy.

The analysis of behavior in orbit GSS two series of US early-warning system

NASA Astrophysics Data System (ADS)

Sukhov, P. P.; Epishev, V. P.; Sukhov, K. P.; Motrunych, I. I.

2016-09-01

Satellites Early Warning System Series class SBIRS US Air Force must replace on GEO early series DSP Series. During 2014-2016 the authors received more than 30 light curves "DSP-18 and "Sbirs-Geo 2". The analysis of the behavior of these satellites in orbit by a coordinate and photometric data. It is shown that for the monitoring of the Earth's surface is enough to place GEO 4 unit SBIRS across 90 deg.

Geochemistry of Israeli oil shales - A review

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shirav, M.; Ginzbury, D.

1983-02-01

The oil shales in Israel are widely distributed throughout the country. Outcrops are rare and the information is based on boreholes data. The oil shale sequence is of UpperCampanian - Maastrichtian age and belongs to the Chareb Formation. In places, part of the phosphorite layer below the oil shales is also rich in kerogen. The host rocks are biomicritic limestones and marls, in which the organic matter is generally homogeneously and finely dispersed. The occurrence of authigenic feldspar and the preservation of the organic matter (up to 26% of the total rock) indicate euxinic hypersaline conditions which prevailed in themore » relative closed basins of deposition during the Maastrichtian. Current reserves of oil shales in Israel are about 3,500 million tons, located in the following deposits: Zin, Oron, Ef'e, Hartuv and Nabi-Musa. The 'En Bokek deposit, although thoroughly investigated, is of limited reserves and is not considered for future exploitation. Other potential areas, in the Northern Negev and along the Coastal Plain are under investigation. Future successful utilization of the Israeli oil shales, either by fluidizid-bed combustion or by retorting will contribute to the state's energy balance.« less

A small azhdarchoid pterosaur from the latest Cretaceous, the age of flying giants.

PubMed

Martin-Silverstone, Elizabeth; Witton, Mark P; Arbour, Victoria M; Currie, Philip J

2016-08-01

Pterosaur fossils from the Campanian-Maastrichtian of North America have been reported from the continental interior, but few have been described from the west coast. The first pterosaur from the Campanian Northumberland Formation (Nanaimo Group) of Hornby Island, British Columbia, is represented here by a humerus, dorsal vertebrae (including three fused notarial vertebrae), and other fragments. The elements have features typical of Azhdarchoidea, an identification consistent with dominance of this group in the latest Cretaceous. The new material is significant for its size and ontogenetic stage: the humerus and vertebrae indicate a wingspan of ca 1.5 m, but histological sections and bone fusions indicate the individual was approaching maturity at time of death. Pterosaurs of this size are exceedingly rare in Upper Cretaceous strata, a phenomenon commonly attributed to smaller pterosaurs becoming extinct in the Late Cretaceous as part of a reduction in pterosaur diversity and disparity. The absence of small juveniles of large species-which must have existed-in the fossil record is evidence of a preservational bias against small pterosaurs in the Late Cretaceous, and caution should be applied to any interpretation of latest Cretaceous pterosaur diversity and success.

Sentinel Hill Core Test 1: Facies Descriptions and Stratigraphic Reinterpretations of the Prince Creek and Schrader Bluff Formations, North Slope, Alaska

USGS Publications Warehouse

Flores, Romeo M.; Stricker, Gary D.; Decker, Paul L.; Myers, Mark D.

2007-01-01

The Sentinel Hill Core Test 1 well penetrated an intertonguing sequence of (1) the marine Schrader Bluff Formation in the depth intervals 950?1,180 ft and 690?751 ft, which consists of shoreface and offshore deposits that accumulated along a storm-dominated, barred shoreline; and (2) the nonmarine Prince Creek Formation in the depth intervals 751?950 ft and surface to 690 ft, which consists of fluvial channel, crevasse splay, backswamp, and ash fall deposits. The strata range in age from early Campanian to early Maastrichtian. An erosional contact at a depth of 690 ft at the base of the upper unit of the Prince Creek Formation is interpreted as a major regional sequence boundary, and the overlying conglomeratic fluvial channel deposits are interpreted to have accumulated in a paleovalley. In its more proximal reaches along the Colville River, channels of this paleovalley cut down 75 ft into the lowermost Prince Creek Formation and the uppermost Schrader Bluff Formation. Farther offshore, the equivalent surface to the aforementioned paleovalley appears to be a subtle discontinuity between middle and lower Schrader Bluff Formation shelfal marine strata. Still farther offshore, the equivalent paleovalley surface is interpreted as a marine mass-wasting surface that locally cuts through the lowermost Schrader Bluff Formation and into the underlying Seabee Formation.

Volcanic rocks cored on hess rise, Western Pacific Ocean

USGS Publications Warehouse

Vallier, T.L.; Windom, K.E.; Seifert, K.E.; Thiede, Jorn

1980-01-01

Large aseismic rises and plateaus in the western Pacific include the Ontong-Java Plateau, Magellan Rise, Shatsky Rise, Mid-Pacific Mountains, and Hess Rise. These are relatively old features that rise above surrounding sea floors as bathymetric highs. Thick sequences of carbonate sediments overlie, what are believed to be, Upper Jurassic and Lower Cretaceous volcanic pedestals. We discuss here petrological and tectonic implications of data from volcanic rocks cored on Hess Rise. The data suggest that Hess Rise originated at a spreading centre in the late early Cretaceous (Aptian-Albian stages). Subsequent off-ridge volcanism in the late Albian-early Cenomanian stages built a large archipelago of oceanic islands and seamounts composed, at least in part, of alkalic rocks. The volcanic platform subsided during its northward passage through the mid-Cretaceousequatorial zone. Faulting and uplift, and possibly volcanism, occurred in the latest Cretaceous (Campanian-Maastrichtian stages). Since then, Hess Rise continued its northward movement and subsidence. Volcanic rocks from holes drilled on Hess Rise during IPOD Leg 62 (Fig. 1) are briefly described here and we relate the petrological data to the origin and evolution of that rise. These are the first volcanic rocks reported from Hess Rise. ?? 1980 Nature Publishing Group.

The Blake Nose Cretaceous-Paleogene (Florida Atlantic margin, ODP Leg 171B): an exemplar record of the Maastrichtian-Danian transition

USGS Publications Warehouse

Bellier, J.-P.; Marca, S.; Norris, R.D.; Kroon, D.; Klaus, A.; Alexander, I.T.; Bardot, L.P.; Barker, C.E.; Blome, C.D.; Clarke, L.J.; Erbacher, J.; Faul, K.L.; Holmes, M.A.; Huber, B.T.; Katz, M.E.; MacLeod, K.G.; Martinez-Ruiz, F. C.; Mita, I.; Nakai, M.; Ogg, James G.; Pak, D.K.; Pletsch, T.K.; ,; Shackleton, N.J.; Smit, J.; Ussler, W.; Watkins, D.K.; Widmark, J.; Wilson, P.A.

1997-01-01

During ODP Leg 171B, devoted to the analysis of the Blake Plateau margin in front of Florida, 16 holes have been drilled in 5 distinct sites. The sites have documented a sedimentary succession ranging in age from Aptian to Eocene. Emphasis has been put on critical periods, comprising the Paleocene-Eocene transition, the Cretaceous-Tertiary boundary which has been cored in excellent conditions, the middle Maastrichtian extinctions and the Albian anoxic episodes.

Phase equilibria constraints on the chemical and physical evolution of the campanian ignimbrite

USGS Publications Warehouse

Fowler, S.J.; Spera, F.J.; Bohrson, W.A.; Belkin, H.E.; de Vivo, B.

2007-01-01

The Campanian Ignimbrite is a > 200 km3 trachyte-phonolite pyroclastic deposit that erupted at 39.3 ?? 0.1 ka within the Campi Flegrei west of Naples, Italy. Here we test the hypothesis that Campanian Ignimbrite magma was derived by isobaric crystal fractionation of a parental basaltic trachyandesitic melt that reacted and came into local equilibrium with small amounts (5-10 wt%) of crustal rock (skarns and foid-syenites) during crystallization. Comparison of observed crystal and magma compositions with results of phase equilibria assimilation-fractionation simulations (MELTS) is generally very good. Oxygen fugacity was approximately buffered along QFM+1 (where QFM is the quartz-fayalite-magnetite buffer) during isobaric fractionation at 0.15 GPa (???6 km depth). The parental melt, reconstructed from melt inclusion and host clinopyroxene compositions, is found to be basaltic trachyandesite liquid (51.1 wt% SiO2, 9.3 wt% MgO, 3 wt% H2O). A significant feature of phase equilibria simulations is the existence of a pseudo-invariant temperature, ???883??C, at which the fraction of melt remaining in the system decreases abruptly from ???0.5 to < 0.1. Crystallization at the pseudo-invariant point leads to abrupt changes in the composition, properties (density, dissolved water content), and physical state (viscosity, volume fraction fluid) of melt and magma. A dramatic decrease in melt viscosity (from 1700 Pa s to ???200 Pa s), coupled with a change in the volume fraction of water in magma (from ??? 0.1 to 0.8) and a dramatic decrease in melt and magma density acted as a destabilizing eruption trigger. Thermal models suggest a timescale of ??? 200 kyr from the beginning of fractionation until eruption, leading to an apparent rate of evolved magma generation of about 10-3 km3/year. In situ crystallization and crystal settling in density-stratified regions, as well as in convectively mixed, less evolved subjacent magma, operate rapidly enough to match this apparent

PyORBIT: A Python Shell For ORBIT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jean-Francois Ostiguy; Jeffrey Holmes

2003-07-01

ORBIT is code developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. The code is structured as a collection of external C++ modules for SuperCode, a high level interpreter shell developed at LLNL in the early 1990s. SuperCode is no longer actively supported and there has for some time been interest in replacing it by a modern scripting language, while preserving the feel of the original ORBIT program. In this paper, we describe a new version of ORBIT where the role of SuperCode is assumed by Python, a free, well-documented and widely supported object-oriented scripting language. Wemore » also compare PyORBIT to ORBIT from the standpoint of features, performance and future expandability.« less

The Hot Orbit: Orbital Cellulitis

PubMed Central

Chaudhry, Imtiaz A.; Al-Rashed, Waleed; Arat, Yonca O.

2012-01-01

Orbital cellulitis is an uncommon condition previously associated with severe complications. If untreated, orbital cellulitis can be potentially sight and life threatening. It can affect both adults and children but has a greater tendency to occur in the pediatric age group. The infection most commonly originates from sinuses, eyelids or face, retained foreign bodies, or distant soources by hematogenous spread. It is characterized by eyelid edema, erythema, chemosis, proptosis, blurred vision, fever, headache, and double vision. A history of upper respiratory tract infection prior to the onset is very common especially in children. In the era prior to antibiotics, vision loss from orbital cellulitis was a dreaded complication. Currently, imaging studies for detection of orbital abcess, the use of antibiotics and early drainage have mitigated visual morbidity significantly. The purpose of this review is to describe current investigative strategies and management options in the treatment of orbital cellulitis, establish their effectiveness and possible complications due to late intervention. PMID:22346113

Mosasaurs (Reptilia) from the late Maastrichtian (Late Cretaceous) of northern Patagonia (Río Negro, Argentina)

NASA Astrophysics Data System (ADS)

Fernández, Marta; Martin, James; Casadío, Silvio

2008-03-01

A diverse assemblage of mosasaurs was recently recovered from the Jagüel Formation (late Maastrichtian) exposed at three localities of northern Patagonia (Río Negro, Argentina). Four taxa (three mosasaurines and a plioplatecarpine) have been identified, and three of these marine reptiles can be identified at lower taxonomic levels: Mosasaurus sp. aff. M. hoffmanni, Plioplatecarpus sp., and Prognathodon sp. These occurrences are significant because they represent the first diagnostic material at generic level exhumed from Patagonia and include one of the youngest mosasaurs found worldwide. One of the specimens described herein was found only 1.5 m below the Cretaceous/Tertiary boundary. Only mosasaurs from Antarctica found within a meter of the boundary are known to occur higher in the geologic section.

Continental weathering as a driver of Late Cretaceous cooling: new insights from clay mineralogy of Campanian sediments from the southern Tethyan margin to the Boreal realm

NASA Astrophysics Data System (ADS)

Chenot, Elise; Deconinck, Jean-François; Pucéat, Emmanuelle; Pellenard, Pierre; Guiraud, Michel; Jaubert, Maxime; Jarvis, Ian; Thibault, Nicolas; Cocquerez, Théophile; Bruneau, Ludovic; Razmjooei, Mohammad J.; Boussaha, Myriam; Richard, James; Sizun, Jean-Pierre; Stemmerik, Lars

2018-03-01

New clay mineralogical analyses have been performed on Campanian sediments from the Tethyan and Boreal realms along a palaeolatitudinal transect from 45° to 20°N (Danish Basin, North Sea, Paris Basin, Mons Basin, Aquitaine Basin, Umbria-Marche Basin and Tunisian Atlas). Significant terrigenous inputs are evidenced by increasing proportions of detrital clay minerals such as illite, kaolinite and chlorite at various levels in the mid- to upper Campanian, while smectitic minerals predominate and represented the background of the Late Cretaceous clay sedimentation. Our new results highlight a distinct latitudinal distribution of clay minerals, with the occurrence of kaolinite in southern sections and an almost total absence of this mineral in northern areas. This latitudinal trend points to an at least partial climatic control on clay mineral sedimentation, with a humid zone developed between 20° and 35°N. The association and co-evolution of illite, chlorite and kaolinite in most sections suggest a reworking of these minerals from basement rocks weathered by hydrolysis, which we link to the formation of relief around the Tethys due to compression associated with incipient Tethyan closure. Diachronism in the occurrence of detrital minerals between sections, with detrital input starting earlier during the Santonian in the south than in the north, highlights the northward progression of the deformation related to the anticlockwise rotation of Africa. Increasing continental weathering and erosion, evidenced by our clay mineralogical data through the Campanian, may have resulted in enhanced CO2 consumption by silicate weathering, thereby contributing to Late Cretaceous climatic cooling.

Electrofacies vs. lithofacies sandstone reservoir characterization Campanian sequence, Arshad gas/oil field, Central Sirt Basin, Libya

NASA Astrophysics Data System (ADS)

Burki, Milad; Darwish, Mohamed

2017-06-01

The present study focuses on the vertically stacked sandstones of the Arshad Sandstone in Arshad gas/oil field, Central Sirt Basin, Libya, and is based on the conventional cores analysis and wireline log interpretation. Six lithofacies types (F1 to F6) were identified based on the lithology, sedimentary structures and biogenic features, and are supported by wireline log calibration. From which four types (F1-F4) represent the main Campanian sandstone reservoirs in the Arshad gas/oil field. Lithofacies F5 is the basal conglomerates at the lower part of the Arshad sandstones. The Paleozoic Gargaf Formation is represented by lithofacies F6 which is the source provenance for the above lithofacies types. Arshad sediments are interpreted to be deposited in shallow marginal and nearshore marine environment influenced by waves and storms representing interactive shelf to fluvio-marine conditions. The main seal rocks are the Campanian Sirte shale deposited in a major flooding events during sea level rise. It is contended that the syn-depositional tectonics controlled the distribution of the reservoir facies in time and space. In addition, the post-depositional changes controlled the reservoir quality and performance. Petrophysical interpretation from the porosity log values were confirmed by the conventional core measurements of the different sandstone lithofacies types. Porosity ranges from 5 to 20% and permeability is between 0 and 20 mD. Petrophysical cut-off summary of the lower part of the clastic dominated sequence (i. e. Arshad Sandstone) calculated from six wells includes net pay sand ranging from 19.5‧ to 202.05‧, average porosity from 7.7 to 15% and water saturation from 19 to 58%.

A review on the structural styles of deformation during Late Cretaceous and Paleocene tectonic phases in the southern North Sea area

NASA Astrophysics Data System (ADS)

Deckers, Jef; van der Voet, Eva

2018-04-01

The Mesozoic rifts in the southern North Sea area were affected by Late Cretaceous to Paleocene inversion. Two main inversion phases were traditionally identified in this interval: the Sub-Hercynian and the Laramide phases. The Sub-Hercynian phase started in the early Late Cretaceous, peaked during the Campanian and ended in the late Maastrichtian, while the Laramide phase started in the late Danian and ended in the Thanetian. The Late Cretaceous Sub-Hercynian phase was strong and occurred in several pulses. These pulses led to basin-scale uplift by large reverse movements along basin-bounding faults and resulted in large amounts of erosion (up to 2 km) of Mesozoic and older sediments. The middle Paleocene Laramide phase on the other hand resulted in mild, domal uplift of some Late Cretaceous inverted basins and subsidence (into depocenters) of others. The subsequent Cenozoic inversion phases displayed similar or lower amplitudes and wavelengths of vertical surface movements as the Laramide phase. The transition from the Sub-Hercynian to the Laramide phase in the southern North Sea area therefore coincides with the overall transition from fault-controlled inversion to broad domal vertical surface movements.

Rehabilitation of orbital cavity after orbital exenteration using polymethyl methacrylate orbital prosthesis.

PubMed

Jain, Sumeet; Jain, Parul

2016-01-01

Squamous cell carcinoma of the eyelid is the second most common malignant neoplasm of the eye with the incidence of 0.09 and 2.42 cases/100 000 people. Orbital invasion is a rare complication but, if recognized early, can be treated effectively with exenteration. Although with advancements in technology such as computer-aided design and computer-aided manufacturing, material science, and retentive methods like implants, orbital prosthesis with stock ocular prosthesis made of methyl methacrylate retained by anatomic undercuts is quiet effective and should not be overlooked and forgotten. This clinical report describes prosthetic rehabilitation of two male patients with polymethyl methacrylate resin orbital prosthesis after orbital exenteration, for squamous cell carcinoma of the upper eyelid. The orbital prosthesis was sufficiently retained by hard and soft tissue undercuts without any complications. The patients using the prosthesis are quite satisfied with the cosmetic results and felt comfortable attending the social events.

The last dinosaurs of Brazil: The Bauru Group and its implications for the end-Cretaceous mass extinction.

PubMed

Brusatte, Stephen L; Candeiro, Carlos R A; Simbras, Felipe M

2017-01-01

The non-avian dinosaurs died out at the end of the Cretaceous, ~66 million years ago, after an asteroid impact. The prevailing hypothesis is that the effects of the impact suddenly killed the dinosaurs, but the poor fossil record of latest Cretaceous (Campanian-Maastrichtian) dinosaurs from outside Laurasia (and even more particularly, North America) makes it difficult to test specific extinction scenarios. Over the past few decades, a wealth of new discoveries from the Bauru Group of Brazil has revealed a unique window into the evolution of terminal Cretaceous dinosaurs from the southern continents. We review this record and demonstrate that there was a diversity of dinosaurs, of varying body sizes, diets, and ecological roles, that survived to the very end of the Cretaceous (Maastrichtian: 72-66 million years ago) in Brazil, including a core fauna of titanosaurian sauropods and abelisaurid and carcharodontosaurid theropods, along with a variety of small-to-mid-sized theropods. We argue that this pattern best fits the hypothesis that southern dinosaurs, like their northern counterparts, were still diversifying and occupying prominent roles in their ecosystems before the asteroid suddenly caused their extinction. However, this hypothesis remains to be tested with more refined paleontological and geochronological data, and we give suggestions for future work.

Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards

PubMed Central

Lowe, John; Barton, Nick; Blockley, Simon; Ramsey, Christopher Bronk; Cullen, Victoria L.; Davies, William; Gamble, Clive; Grant, Katharine; Hardiman, Mark; Housley, Rupert; Lane, Christine S.; Lee, Sharen; Lewis, Mark; MacLeod, Alison; Menzies, Martin; Müller, Wolfgang; Pollard, Mark; Price, Catherine; Roberts, Andrew P.; Rohling, Eelco J.; Satow, Chris; Smith, Victoria C.; Stringer, Chris B.; Tomlinson, Emma L.; White, Dustin; Albert, Paul; Arienzo, Ilenia; Barker, Graeme; Borić, Dušan; Carandente, Antonio; Civetta, Lucia; Ferrier, Catherine; Guadelli, Jean-Luc; Karkanas, Panagiotis; Koumouzelis, Margarita; Müller, Ulrich C.; Orsi, Giovanni; Pross, Jörg; Rosi, Mauro; Shalamanov-Korobar, Ljiljiana; Sirakov, Nikolay; Tzedakis, Polychronis C.

2012-01-01

Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters. PMID:22826222

Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards.

PubMed

Lowe, John; Barton, Nick; Blockley, Simon; Ramsey, Christopher Bronk; Cullen, Victoria L; Davies, William; Gamble, Clive; Grant, Katharine; Hardiman, Mark; Housley, Rupert; Lane, Christine S; Lee, Sharen; Lewis, Mark; MacLeod, Alison; Menzies, Martin; Müller, Wolfgang; Pollard, Mark; Price, Catherine; Roberts, Andrew P; Rohling, Eelco J; Satow, Chris; Smith, Victoria C; Stringer, Chris B; Tomlinson, Emma L; White, Dustin; Albert, Paul; Arienzo, Ilenia; Barker, Graeme; Boric, Dusan; Carandente, Antonio; Civetta, Lucia; Ferrier, Catherine; Guadelli, Jean-Luc; Karkanas, Panagiotis; Koumouzelis, Margarita; Müller, Ulrich C; Orsi, Giovanni; Pross, Jörg; Rosi, Mauro; Shalamanov-Korobar, Ljiljiana; Sirakov, Nikolay; Tzedakis, Polychronis C

2012-08-21

Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters.

Paleoenvironmental reconstruction based on palynofacies analyses of the Cansona Formation (Late Cretaceous), Sinú-San Jacinto Basin, northwest Colombia

NASA Astrophysics Data System (ADS)

Juliao-Lemus, Tatiana; Carvalho, Marcelo de Araujo; Torres, Diego; Plata, Angelo; Parra, Carlos

2016-08-01

To reconstruct the paleoenvironments of the Cansona Formation, a Cretaceous succession in Colombia that has controversial paleoenvironmental interpretation, occasionally deep marine and occasionally shallow marine, palynofacies analyses were conducted on 93 samples from four sections of the Sinú San Jacinto Basin in the north, midwest, and southwest sectors. For the palynofacies analyses, the kerogen categories were counted and subjected to cluster analyses. Four palynofacies associations were revealed for the four sections: Palynofacies Association I (PA I), which consisted of microforaminiferal linings, scolecodonts, dinoflagellate cysts, pollen grains, and fungi hyphae; PA II, which consisted of phytoclast translucent non-biostructured and biostructured, opaque phytoclasts (equidimensional and lath shaped); PA III, which consisted of pseudoamorphous particles, cuticles, resin, and fungal spores; and PA IV, which consisted of fluorescent and non-fluorescent amorphous organic matter and the fresh-water algae Botryococcus. In contrast to early studies that suggested a generalization of the depositional environment for the Cansona Formation (deep or shallow conditions), this study suggests that the formation reflects conspicuous stratigraphic and lateral changes and hence different depositional environments. The Cerro Cansona (CC4 section) and Chalán (AP section) areas are a more marine proximal settings (Early Campanian-Maastrichtian), and there is an intermediate setting for the Lorica area (SC section) and deeper conditions for the Montería area (CP2 section).

Lunar orbiting prospector

NASA Technical Reports Server (NTRS)

1988-01-01

One of the prime reasons for establishing a manned lunar presence is the possibility of using the potential lunar resources. The Lunar Orbital Prospector (LOP) is a lunar orbiting platform whose mission is to prospect and explore the Moon from orbit in support of early lunar colonization and exploitation efforts. The LOP mission is divided into three primary phases: transport from Earth to low lunar orbit (LLO), operation in lunar orbit, and platform servicing in lunar orbit. The platform alters its orbit to obtain the desired surface viewing, and the orbit can be changed periodically as needed. After completion of the inital remote sensing mission, more ambitious and/or complicated prospecting and exploration missions can be contemplated. A refueled propulsion module, updated instruments, or additional remote sensing packages can be flown up from the lunar base to the platform.

Seasonal Equability in Late Cretaceous Central-Eastern Iberia? Inferences from Isotopic Data on Vertebrates

NASA Astrophysics Data System (ADS)

Domingo, L.; Barroso-Barcenilla, F.; Cambra-Moo, O.

2013-12-01

After the mid-Cretaceous thermal maximum, the latest Cretaceous witnessed a long-term cooling trend (Santonian-Maastrichtian). It has been proposed that seasonal equability (low mean annual range of temperatures) accompanied the mid-Cretaceous greenhouse period, but was it also a climatic feature of the colder latest Cretaceous? Terrestrial proxies have proven useful in understanding past seasonality and in this vein, we performed oxygen isotope analyses of the phosphate (δ18OPO4) on the rich and exceptionally well preserved late Campanian-early Maastrichtian vertebrate assemblage of 'Lo Hueco' fossil site (Cuenca, Spain). We analysed theropod and crocodilian tooth enamel, turtle shell, and gar ganoine with the aim of evaluating paleoclimatic conditions existing in the western area of the Tethys realm. The 'Lo Hueco' locality was situated at a paleo-latitude of 31°N and sedimentological and paleontological studies point to a coastal environment with distributary channels and sporadic sabkhas. Samples were collected from two different levels: G1 (proximal muddy floodplain) and G2 (distal muddy floodplain), with G1 being older. δ18OH2O values were calculated from theropod, crocodilian and turtle δ18OPO4 values using established equations and in all cases they are in good agreement with precipitation water from subtropical latest Cretaceous and modern settings. Theropods recorded consistently slightly lower δ18OH2O values (G1: -4.1×1.4‰, G2: -3.5×0.5‰) than crocodilians (G1: -3.6×0.6‰, G2: -2.7×0.6‰) and turtles (G1: -3.8×0.6‰, G2: -2.9×0.5‰). This may be due to terrestrial endothermic taxa, such as theropods, recording ingested water year round, meanwhile semiaquatic ectothermic taxa, such as crocodilians and turtles, would record δ18OH2O values representing local meteoric waters over the warm season, when conditions are favorable for apatite synthesis. With these δ18OH2O values, we used gar ganoine δ18OPO4 values as an independent proxy to

Neodymium isotope evolution of NW Tethyan upper ocean waters throughout the Cretaceous

NASA Astrophysics Data System (ADS)

Pucéat, Emmanuelle; Lécuyer, Christophe; Reisberg, Laurie

2005-08-01

Neodymium isotope compositions of twenty-four fish teeth, nineteen from the NW Tethys and five from different locations within the Tethys, are interpreted to reflect the evolution of Tethyan upper ocean water composition during the Cretaceous and used to track changes in erosional inputs to the NW Tethys and in oceanic circulation throughout the Cretaceous. The rather high ɛNd (up to - 7.6) of the NW Tethyan upper ocean waters recorded from the Late Berriasian to the Early Aptian and the absence of negative excursions during this interval support the presence of a permanent westward flowing Tethys Circumglobal Current (TCC). This implies that temperature variations during this time period, inferred from the oxygen isotope analysis of fish tooth enamel, were not driven by changes in surface oceanic currents, but rather by global climatic changes. The results presented here represent a significant advance over previously published Cretaceous seawater Nd isotope records. Our newly acquired data now allow the identification of two stages of low ɛNd values in the NW Tethys, during the Early Albian-Middle Albian interval (down to - 10) and the Santonian-Early Campanian (down to - 11.4), which alternate with two stages of higher ɛNd values (up to - 9) during the Late Albian-Turonian interval and the Maastrichtian. Used in conjunction with the oxygen isotope record, the fluctuations of ɛNd values can be related to major climatic, oceanographic, and tectonic events that appeared in the western Tethyan domain.

Lamniform Shark Teeth from the Late Cretaceous of Southernmost South America (Santa Cruz Province, Argentina)

PubMed Central

Schroeter, Elena R.; Egerton, Victoria M.; Ibiricu, Lucio M.; Lacovara, Kenneth J.

2014-01-01

Here we report multiple lamniform shark teeth recovered from fluvial sediments in the (Campanian-Maastrichtian) Cerro Fortaleza Formation, Santa Cruz Province, Argentina. This small tooth assemblage is compared to various lamniform sharks possessing similar dental morphologies, including Archaeolamna, Cretalamna, Dwardius, Dallasiella, and Cretodus. Although the teeth share numerous morphological features with the genus Archaeolamna, including a developed neck that maintains a relatively consistent width along the base of the crown, the small sample size and incomplete nature of these specimens precludes definitive taxonomic assignment. Regardless, the discovery of selachian teeth unique from those previously described for the region broadens the known diversity of Late Cretaceous South American sharks. Additionally, the discovery of the teeth in fluvial sandstone may indicate a euryhaline paleobiology in the lamniform taxon or taxa represented by this tooth assemblage. PMID:25141301

Stratigraphic correlation of the Late Cretaceous Simsima Formation United Arab Emirates and Akveren Formation, northwest Turkey

NASA Astrophysics Data System (ADS)

Abdelghany, O.; Abu Saima, M.; Ramazanoglu, S.; Arman, H.

2015-11-01

Latest Cretaceous (Campanian-Maastrichtian) microfossils are used to correlate the carbonate rocks of the Simsima Formation in the northeastern part of the Arabian Peninsula (Northern Oman Mountains, United Arab Emirates and Oman) with the Akveren Formation in Kandira (northwest Turkey, near Black Sea region). Both formations have characteristically rich planktonic foraminiferal and calcareous nannofossil faunal assemblages that permit the recognition of the Globotruncanella havanensis Zone and Quadrum sissinghii Zone CC22. The palaeontological data is used to build an appropriate palaeoenvironmental model for the latest Cretaceous Aruma Group in the Oman Mountains foreland basin. The study reveals that the Late Cretaceous formations of UAE and Turkey can be divided into an open marine carbonate shelf facies (planktonic foraminifera/calcareous nannofossil biomicrite) and a shallow-marine carbonate facies (rudistids, coralline algal foraminiferal biomicrite).

Lamniform shark teeth from the late cretaceous of southernmost South America (Santa Cruz province, Argentina).

PubMed

Schroeter, Elena R; Egerton, Victoria M; Ibiricu, Lucio M; Lacovara, Kenneth J

2014-01-01

Here we report multiple lamniform shark teeth recovered from fluvial sediments in the (Campanian-Maastrichtian) Cerro Fortaleza Formation, Santa Cruz Province, Argentina. This small tooth assemblage is compared to various lamniform sharks possessing similar dental morphologies, including Archaeolamna, Cretalamna, Dwardius, Dallasiella, and Cretodus. Although the teeth share numerous morphological features with the genus Archaeolamna, including a developed neck that maintains a relatively consistent width along the base of the crown, the small sample size and incomplete nature of these specimens precludes definitive taxonomic assignment. Regardless, the discovery of selachian teeth unique from those previously described for the region broadens the known diversity of Late Cretaceous South American sharks. Additionally, the discovery of the teeth in fluvial sandstone may indicate a euryhaline paleobiology in the lamniform taxon or taxa represented by this tooth assemblage.

Tephra dispersal during the Campanian Ignimbrite (Italy) eruption: implications for ultra-distal ash transport during the large caldera-forming eruption

NASA Astrophysics Data System (ADS)

Smith, Victoria C.; Isaia, Roberto; Engwell, Sam L.; Albert, Paul. G.

2016-06-01

The Campanian Ignimbrite eruption dispersed ash over much of the central eastern Mediterranean Sea and eastern Europe. The eruption started with a Plinian phase that was followed by a series of pyroclastic density currents (PDCs) associated with the collapse of the Plinian column and the caldera. The glass compositions of the deposits span a wide geochemical range, but the Plinian fallout and PDCs associated with column collapse, the Lower Pumice Flow, only erupted the most evolved compositions. The later PDCs, the Breccia Museo and Upper Pumice Flow, erupted during and after caldera collapse, tap a less evolved component, and intermediate compositions that represent mixing between the end-members. The range of glass compositions in the Campanian Ignimbrite deposits from sites across the central and eastern Mediterranean Sea allow us to trace the dispersal of the different phases of this caldera-forming eruption. We map the fallout from the Plinian column and the plumes of fine material associated with the PDCs (co-PDCs) across the entire dispersal area. This cannot be done using the usual grain-size methods as deposits in these distal regions do not retain characteristics that allow attribution to either the Plinian or co-PDC phases. The glass compositions of the tephra at ultra-distal sites (>1500 km from the vent) match those of the uppermost PDC units, suggesting that most of the ultra-distal dispersal was associated with the late co-PDC plume that was generated during caldera collapse.

Orbiter Interface Unit and Early Communication System

NASA Technical Reports Server (NTRS)

Cobbs, Ronald M.; Cooke, Michael P.; Cox, Gary L.; Ellenberger, Richard; Fink, Patrick W.; Haynes, Dena S.; Hyams, Buddy; Ling, Robert Y.; Neighbors, Helen M.; Phan, Chau T.;

The Global Precipitation Measurement (GPM) Microwave Imager (GMI): Instrument Overview and Early On-Orbit Performance

NASA Technical Reports Server (NTRS)

Draper, David W.; Newell, David A.; Wentz, Frank J.; Krimchansky, Sergey; Jackson, Gail

2015-01-01

The Global Precipitation Measurement (GPM) mission is an international satellite mission that uses measurements from an advanced radar/radiometer system on a core observatory as reference standards to unify and advance precipitation estimates made by a constellation of research and operational microwave sensors. The GPM core observatory was launched on February 27, 2014 at 18:37 UT in a 65? inclination nonsun-synchronous orbit. GPM focuses on precipitation as a key component of the Earth's water and energy cycle, and has the capability to provide near-real-time observations for tracking severe weather events, monitoring freshwater resources, and other societal applications. The GPM microwave imager (GMI) on the core observatory provides the direct link to the constellation radiometer sensors, which fly mainly in polar orbits. The GMI sensitivity, accuracy, and stability play a crucial role in unifying the measurements from the GPM constellation of satellites. The instrument has exhibited highly stable operations through the duration of the calibration/validation period. This paper provides an overview of the GMI instrument and a report of early on-orbit commissioning activities. It discusses the on-orbit radiometric sensitivity, absolute calibration accuracy, and stability for each radiometric channel. Index Terms-Calibration accuracy, passive microwave remote sensing, radiometric sensitivity.

Update on orbital reconstruction.

PubMed

Chen, Chien-Tzung; Chen, Yu-Ray

2010-08-01

Orbital trauma is common and frequently complicated by ocular injuries. The recent literature on orbital fracture is analyzed with emphasis on epidemiological data assessment, surgical timing, method of approach and reconstruction materials. Computed tomographic (CT) scan has become a routine evaluation tool for orbital trauma, and mobile CT can be applied intraoperatively if necessary. Concomitant serious ocular injury should be carefully evaluated preoperatively. Patients presenting with nonresolving oculocardiac reflex, 'white-eyed' blowout fracture, or diplopia with a positive forced duction test and CT evidence of orbital tissue entrapment require early surgical repair. Otherwise, enophthalmos can be corrected by late surgery with a similar outcome to early surgery. The use of an endoscope-assisted approach for orbital reconstruction continues to grow, offering an alternative method. Advances in alloplastic materials have improved surgical outcome and shortened operating time. In this review of modern orbital reconstruction, several controversial issues such as surgical indication, surgical timing, method of approach and choice of reconstruction material are discussed. Preoperative fine-cut CT image and thorough ophthalmologic examination are key elements to determine surgical indications. The choice of surgical approach and reconstruction materials much depends on the surgeon's experience and the reconstruction area. Prefabricated alloplastic implants together with image software and stereolithographic models are significant advances that help to more accurately reconstruct the traumatized orbit. The recent evolution of orbit reconstruction improves functional and aesthetic results and minimizes surgical complications.

MESSENGER at Mercury: Early Orbital Operations

NASA Technical Reports Server (NTRS)

McNutt, Ralph L., Jr; Solomon, Sean C.; Bedini, Peter D.; Anderson, Brian J.; Blewett, David T.; Evans, Larry G.; Gold, Robert E.; Krimigis, Stamatios M.; Murchie, Scott L.; Nittler, Larry R.;

MESSENGER at Mercury: Early Orbital Operations

NASA Technical Reports Server (NTRS)

McNutt, Ralph L., Jr.; Solomon, Sean C.; Bedini, Peter D.; Anderson, Brian J.; Blewett, David T.; Evans, Larry G.; Gold, Robert E.; Krimigis, Stamatios M.; Murchie, Scott L.; Nittler, Larry R.;

A new chasmosaurine from northern Laramidia expands frill disparity in ceratopsid dinosaurs.

PubMed

Ryan, Michael J; Evans, David C; Currie, Philip J; Loewen, Mark A

2014-06-01

A new taxon of chasmosaurine ceratopsid demonstrates unexpected disparity in parietosquamosal frill shape among ceratopsid dinosaurs early in their evolutionary radiation. The new taxon is described based on two apomorphic squamosals collected from approximately time equivalent (approximately 77 million years old) sections of the upper Judith River Formation, Montana, and the lower Dinosaur Park Formation of Dinosaur Provincial Park, Alberta. It is referred to Chasmosaurinae based on the inferred elongate morphology. The typical chasmosaurine squamosal forms an obtuse triangle in dorsal view that tapers towards the posterolateral corner of the frill. In the dorsal view of the new taxon, the lateral margin of the squamosal is hatchet-shaped with the posterior portion modified into a constricted narrow bar that would have supported the lateral margin of a robust parietal. The new taxon represents the oldest chasmosaurine from Canada, and the first pre-Maastrichtian ceratopsid to have been collected on both sides of the Canada-US border, with a minimum north-south range of 380 km. This squamosal morphology would have given the frill of the new taxon a unique dorsal profile that represents evolutionary experimentation in frill signalling near the origin of chasmosaurine ceratopsids and reinforces biogeographic differences between northern and southern faunal provinces in the Campanian of North America.

Maestrichtian benthic foraminifers from Ocean Point, North Slope, Alaska ( USA).

USGS Publications Warehouse

McDougall, K.

1987-01-01

Previous studies of fauna and flora from Ocean Point, Alaska, have suggested ages ranging from Campanian to early Eocene and that these assemblages are either highly endemic or commonplace. I demonstrate that the moderately abundant benthic foraminifers constitute early Maestrichtian boreal assemblages common to Canada and northern Europe. Paleoenvironmental analysis indicates that deposition took place in outer neritic settings (50 to 150m). The Ocean Point benthic foraminiferal assemblages contain species that migrated from the US Gulf Coast, North American Interior and Europe during the Campanian, and from Europe during the Maestrichtian. These faunal affinities suggest that seaways connected the Arctic to the North American Interior and Atlantic during the Campanian and that a shallow seaway connected the Arctic to the Atlantic during the early Maestrichtian. - from Author

3D Computational Mechanics Elucidate the Evolutionary Implications of Orbit Position and Size Diversity of Early Amphibians

PubMed Central

Marcé-Nogué, Jordi; Fortuny, Josep; De Esteban-Trivigno, Soledad; Sánchez, Montserrat; Gil, Lluís; Galobart, Àngel

2015-01-01

For the first time in vertebrate palaeontology, the potential of joining Finite Element Analysis (FEA) and Parametrical Analysis (PA) is used to shed new light on two different cranial parameters from the orbits to evaluate their biomechanical role and evolutionary patterns. The early tetrapod group of Stereospondyls, one of the largest groups of Temnospondyls is used as a case study because its orbits position and size vary hugely within the members of this group. An adult skull of Edingerella madagascariensis was analysed using two different cases of boundary and loading conditions in order to quantify stress and deformation response under a bilateral bite and during skull raising. Firstly, the variation of the original geometry of its orbits was introduced in the models producing new FEA results, allowing the exploration of the ecomorphology, feeding strategy and evolutionary patterns of these top predators. Secondly, the quantitative results were analysed in order to check if the orbit size and position were correlated with different stress patterns. These results revealed that in most of the cases the stress distribution is not affected by changes in the size and position of the orbit. This finding supports the high mechanical plasticity of this group during the Triassic period. The absence of mechanical constraints regarding the orbit probably promoted the ecomorphological diversity acknowledged for this group, as well as its ecological niche differentiation in the terrestrial Triassic ecosystems in clades as lydekkerinids, trematosaurs, capitosaurs or metoposaurs. PMID:26107295

Early Assessment of VIIRS On-Orbit Calibration and Support Activities

NASA Technical Reports Server (NTRS)

Xiong, Xiaoxiong; Chiang, Kwofu; McIntire, Jeffrey; Oudrari, Hassan; Wu, Aisheng; Schwaller, Mathew; Butler, James

2012-01-01

The Suomi National Polar-orbiting Partnership (S-NPP) satellite, formally the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP), provides a bridge between current and future low-Earth orbiting weather and environmental observation satellite systems. The NASA s NPP VIIRS Characterization Support Team (VCST) is designed to assess the long term geometric and radiometric performance of the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument onboard the S-NPP spacecraft and to support NPP Science Team Principal Investigators (PI) for their independent evaluation of VIIRS Environmental Data Records (EDRs). This paper provides an overview of Suomi NPP VIIRS on-orbit calibration activities and examples of sensor initial on-orbit performance. It focuses on the radiometric calibration support activities and capabilities provided by the NASA VCST.

Skull ecomorphology of megaherbivorous dinosaurs from the dinosaur park formation (upper campanian) of Alberta, Canada.

PubMed

Mallon, Jordan C; Anderson, Jason S

2013-01-01

Megaherbivorous dinosaur coexistence on the Late Cretaceous island continent of Laramidia has long puzzled researchers, owing to the mystery of how so many large herbivores (6-8 sympatric species, in many instances) could coexist on such a small (4-7 million km(2)) landmass. Various explanations have been put forth, one of which-dietary niche partitioning-forms the focus of this study. Here, we apply traditional morphometric methods to the skulls of megaherbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta to infer the ecomorphology of these animals and to test the niche partitioning hypothesis. We find evidence for niche partitioning not only among contemporaneous ankylosaurs, ceratopsids, and hadrosaurids, but also within these clades at the family and subfamily levels. Consubfamilial ceratopsids and hadrosaurids differ insignificantly in their inferred ecomorphologies, which may explain why they rarely overlap stratigraphically: interspecific competition prevented their coexistence.

Skull Ecomorphology of Megaherbivorous Dinosaurs from the Dinosaur Park Formation (Upper Campanian) of Alberta, Canada

PubMed Central

Mallon, Jordan C.; Anderson, Jason S.

2013-01-01

Megaherbivorous dinosaur coexistence on the Late Cretaceous island continent of Laramidia has long puzzled researchers, owing to the mystery of how so many large herbivores (6–8 sympatric species, in many instances) could coexist on such a small (4–7 million km2) landmass. Various explanations have been put forth, one of which–dietary niche partitioning–forms the focus of this study. Here, we apply traditional morphometric methods to the skulls of megaherbivorous dinosaurs from the Dinosaur Park Formation (upper Campanian) of Alberta to infer the ecomorphology of these animals and to test the niche partitioning hypothesis. We find evidence for niche partitioning not only among contemporaneous ankylosaurs, ceratopsids, and hadrosaurids, but also within these clades at the family and subfamily levels. Consubfamilial ceratopsids and hadrosaurids differ insignificantly in their inferred ecomorphologies, which may explain why they rarely overlap stratigraphically: interspecific competition prevented their coexistence. PMID:23874409

The Early Lunar Orbit and Principal Moments of Inertia

NASA Astrophysics Data System (ADS)

Garrick-Bethell, I.; Zuber, M. T.

2007-12-01

If taken at face value, the principal lunar moments of inertia suggest that the Moon froze in a past tidal and rotational state during a high eccentricity orbit [1]. At this time the Moon may have been in either synchronous rotation or in a 3:2 resonance of spin and mean motion. We have performed further investigations of the plausibility of past high eccentricity lunar orbits on the basis of orbital evolution, the dynamics of entry into any past 3:2 resonance, and tidal dissipation. We have found that the requisite permanent (B-A)/C (where A, B, and C are the principal moments of inertia) for a 3:2 resonance can be achieved in a magma ocean if a density anomaly is present shortly after lunar accretion. In a high eccentricity orbit, tidal dissipation will affect the Moon's ability to develop lithospheric strength. The Moon is presently able to support degree-two loads, while Io, which is approximately the same size as the Moon and strongly heated by tidal dissipation, probably cannot [2]. Therefore, somewhere between the present lunar radioactive heating rate (~1012 W), and Io's observed dissipation (~1014 W), the Moon may develop lithospheric strength. We use 1014 W as a loose upper bound on where freeze-in may begin and find that in a 3:2 resonance tidal dissipation [3] can drop below 1014 W at a = 25 RE and e = 0.17, and the present moments of inertia can be approximately reproduced for lunar values of QM = 475 (where a is the lunar semimajor axis, RE is the Earth radius, and Q is the specific dissipation function). This value of QM is somewhat large, but the biggest problem with a 3:2 resonance that lasts until 25 RE is how to achieve the current low eccentricity synchronous orbit. The required damping cannot be easily achieved unless the Moon is knocked out of a 3:2 resonance by an impactor that would produce a crater approximately 800 km in diameter. In sum, there is no single strong constraint that completely rules out a 3:2 resonance, but it would require a

High-precision 14C and 40Ar/39Ar dating of the Campanian Ignimbrite (Y-5) reconciles the time-scales of climatic-cultural processes at 40 ka.

PubMed

Giaccio, Biagio; Hajdas, Irka; Isaia, Roberto; Deino, Alan; Nomade, Sebastien

2017-04-06

The Late Pleistocene Campanian Ignimbrite (CI) super-eruption (Southern Italy) is the largest known volcanic event in the Mediterranean area. The CI tephra is widely dispersed through western Eurasia and occurs in close stratigraphic association with significant palaeoclimatic and Palaeolithic cultural events. Here we present new high-precision 14 C (34.29 ± 0.09 14 C kyr BP, 1σ) and 40 Ar/ 39 Ar (39.85 ± 0.14 ka, 95% confidence level) dating results for the age of the CI eruption, which substantially improve upon or augment previous age determinations and permit fuller exploitation of the chronological potential of the CI tephra marker. These results provide a robust pair of 14 C and 40 Ar/ 39 Ar ages for refining both the radiocarbon calibration curve and the Late Pleistocene time-scale at ca. 40 ka. In addition, these new age constraints provide compelling chronological evidence for the significance of the combined influence of the CI eruption and Heinrich Event 4 on European climate and potentially evolutionary processes of the Early Upper Palaeolithic.

High-precision 14C and 40Ar/39Ar dating of the Campanian Ignimbrite (Y-5) reconciles the time-scales of climatic-cultural processes at 40 ka

PubMed Central

Giaccio, Biagio; Hajdas, Irka; Isaia, Roberto; Deino, Alan; Nomade, Sebastien

2017-01-01

The Late Pleistocene Campanian Ignimbrite (CI) super-eruption (Southern Italy) is the largest known volcanic event in the Mediterranean area. The CI tephra is widely dispersed through western Eurasia and occurs in close stratigraphic association with significant palaeoclimatic and Palaeolithic cultural events. Here we present new high-precision 14C (34.29 ± 0.09 14C kyr BP, 1σ) and 40Ar/39Ar (39.85 ± 0.14 ka, 95% confidence level) dating results for the age of the CI eruption, which substantially improve upon or augment previous age determinations and permit fuller exploitation of the chronological potential of the CI tephra marker. These results provide a robust pair of 14C and 40Ar/39Ar ages for refining both the radiocarbon calibration curve and the Late Pleistocene time-scale at ca. 40 ka. In addition, these new age constraints provide compelling chronological evidence for the significance of the combined influence of the CI eruption and Heinrich Event 4 on European climate and potentially evolutionary processes of the Early Upper Palaeolithic. PMID:28383570

A New Hadrosauroid Dinosaur from the Early Late Cretaceous of Shanxi Province, China

PubMed Central

Wang, Run-Fu; You, Hai-Lu; Xu, Shi-Chao; Wang, Suo-Zhu; Yi, Jian; Xie, Li-Juan; Jia, Lei; Li, Ya-Xian

2013-01-01

Background The origin of hadrosaurid dinosaurs is far from clear, mainly due to the paucity of their early Late Cretaceous close relatives. Compared to numerous Early Cretaceous basal hadrosauroids, which are mainly from Eastern Asia, only six early Late Cretaceous (pre-Campanian) basal hadrosauroids have been found: three from Asia and three from North America. Methodology/Principal Findings Here we describe a new hadrosauroid dinosaur, Yunganglong datongensis gen. et sp. nov., from the early Late Cretaceous Zhumapu Formation of Shanxi Province in northern China. The new taxon is represented by an associated but disarticulated partial adult skeleton including the caudodorsal part of the skull. Cladistic analysis and comparative studies show that Yunganglong represents one of the most basal Late Cretaceous hadrosauroids and is diagnosed by a unique combination of features in its skull and femur. Conclusions/Significance The discovery of Yunganglong adds another record of basal Hadrosauroidea in the early Late Cretaceous, and helps to elucidate the origin and evolution of Hadrosauridae. PMID:24204734

A new hadrosauroid dinosaur from the early late cretaceous of Shanxi Province, China.

PubMed

Wang, Run-Fu; You, Hai-Lu; Xu, Shi-Chao; Wang, Suo-Zhu; Yi, Jian; Xie, Li-Juan; Jia, Lei; Li, Ya-Xian

2013-01-01

The origin of hadrosaurid dinosaurs is far from clear, mainly due to the paucity of their early Late Cretaceous close relatives. Compared to numerous Early Cretaceous basal hadrosauroids, which are mainly from Eastern Asia, only six early Late Cretaceous (pre-Campanian) basal hadrosauroids have been found: three from Asia and three from North America. Here we describe a new hadrosauroid dinosaur, Yunganglong datongensis gen. et sp. nov., from the early Late Cretaceous Zhumapu Formation of Shanxi Province in northern China. The new taxon is represented by an associated but disarticulated partial adult skeleton including the caudodorsal part of the skull. Cladistic analysis and comparative studies show that Yunganglong represents one of the most basal Late Cretaceous hadrosauroids and is diagnosed by a unique combination of features in its skull and femur. The discovery of Yunganglong adds another record of basal Hadrosauroidea in the early Late Cretaceous, and helps to elucidate the origin and evolution of Hadrosauridae.

Bayesian Orbit Computation Tools for Objects on Geocentric Orbits

NASA Astrophysics Data System (ADS)

Virtanen, J.; Granvik, M.; Muinonen, K.; Oszkiewicz, D.

2013-08-01

We consider the space-debris orbital inversion problem via the concept of Bayesian inference. The methodology has been put forward for the orbital analysis of solar system small bodies in early 1990's [7] and results in a full solution of the statistical inverse problem given in terms of a posteriori probability density function (PDF) for the orbital parameters. We demonstrate the applicability of our statistical orbital analysis software to Earth orbiting objects, both using well-established Monte Carlo (MC) techniques (for a review, see e.g. [13] as well as recently developed Markov-chain MC (MCMC) techniques (e.g., [9]). In particular, we exploit the novel virtual observation MCMC method [8], which is based on the characterization of the phase-space volume of orbital solutions before the actual MCMC sampling. Our statistical methods and the resulting PDFs immediately enable probabilistic impact predictions to be carried out. Furthermore, this can be readily done also for very sparse data sets and data sets of poor quality - providing that some a priori information on the observational uncertainty is available. For asteroids, impact probabilities with the Earth from the discovery night onwards have been provided, e.g., by [11] and [10], the latter study includes the sampling of the observational-error standard deviation as a random variable.

Seismo-stratigraphic evolution of the northern Austral Basin and its possible relation to the Andean tectonics, onshore Argentina.

NASA Astrophysics Data System (ADS)

Sachse, Victoria; Anka, Zahie; Pagan, Facundo; Kohler, Guillermina; Cagnolatti, Marcelo; di Primio, Rolando; Rodriguez, Jorge

2013-04-01

The Austral Basin is situated in a formerly and recently high active tectonic zone in southern Argentina. The opening of the South Atlantic to the east, the opening of the Drake Passage in the south, and the subduction related to the rise of the Andes to the west, had major influence on the study area. To identify the impact of the tectonic events on basin geometry, sediment thickness and depocenter migration through time, 2D seismic interpretation was performed for an area of approx. 180.000 km² covering the onshore northern Austral Basin. A total of 10 seismic horizons were mapped and tied to the stratigraphy from well reports, representing 9 syn- and post- rift sequences. The main units are: Basement (U1), Jurassic Tobifera Formation (U2), Early Cretaceous (U3), Late Cretaceous (U4), sub-unit Campanian (U4A), Paleocene (U5), Eocene (U6), Oligocene (U7), Miocene (U8), and Plio-Pleistocene (U9). Main tectonic events are identified representing the break-up phase forming graben systems and the evolution from the ancient backarc Rocas Verdes Basin to the foreland Austral Basin. Inversion and changes in the tectonic regime are concomitant with onlapping and thinning of the base of the Upper Cretaceous to Campanian sediments, while the Top of the Upper Cretaceous represents a Maastrichtian unconformity. Units depth maps show a triangular geometry since the Jurassic, tracing the north-eastern basement high and deepening to the south. Since the Campanian the former geometry of basin fill changed and deepening to the south stopped. Beginning of the foreland phase is assigned to this time as well as changes in the stress regime. Paleogene times are marked by a relatively high sedimentation rate coupled with enduring thermal subsidence, on-going rise of the Andes and changes in the convergence rates of the Nazca relative to the South American plate. Onset of sediment supply from the Andes (Incaic phase) resulted in enhanced sedimentation rates during the Paleocene

A tapestry of orbits

DOE Office of Scientific and Technical Information (OSTI.GOV)

King-Hele, D.

1992-01-01

In this book, the author describes how orbital research developed to yield a rich harvest of knowledge about the earth and its atmosphere. King-Hele relates a personal account of this research based on analysis of satellite orbits between 1957 and 1990 conducted from the Royal Aircraft Establishment in Farnborough England. The early research methods used before the launch of Sputnik in 1957 are discussed.

Early Results from the NASA Orbiting Carbon Observatory-2 (OCO-2)

NASA Astrophysics Data System (ADS)

Crisp, David; Eldering, Annmarie

2015-04-01

The Orbiting Carbon Observatory-2 (OCO-2) is NASA's first satellite designed to collect the measurements needed to estimate the column-averaged carbon dioxide (CO2) dry air mole fraction, XCO2, with the sensitivity, accuracy, and resolution needed to characterize the CO2 sources and sinks on regional scales over the globe. OCO-2 was successfully launched from Vandenberg Air Force Base in California on July 2, 2014 and joined the 705-km Afternoon Constellation (A-Train) on August 3, 2014. The three-channel imaging grating spectrometer was then cooled to its operating temperatures and a comprehensive series of characterization and calibration activities were initiated. Since early October 2014, the observatory has been routinely collecting almost 1 million soundings over the sunlit hemisphere each day. Early cloud screening results indicate that 15-30% of these measurements may be sufficiently cloud free to yield precise estimates of XCO2. Initial deliveries of calibrated, geo-located OCO-2 spectra to the NASA Goddard Earth Science Data and Information Services Center (GES DISC) began on December 30, 2014. Preliminary estimates of XCO2 retrieved from these data are currently being validated against observations from the Total Carbon Column Observing Network (TCCON) and other standards. Routine deliveries XCO2 and other products, including surface pressure and chlorophyll fluorescence, to the GES DISC are expected to begin before the end of March, 2015. This presentation will summarize the status of the OCO-2 mission and the coverage, resolution, and accuracy of its early results.

The trace fossil Lepidenteron lewesiensis (Mantell, 1822) from the Upper Cretaceous of southern Poland

NASA Astrophysics Data System (ADS)

Jurkowska, Agata; Uchman, Alfred

2013-12-01

Jurkowska, A. and Uchman, A. 2013. The trace fossil Lepidenteron lewesiensis (Mantell, 1822) from the Upper Cretaceous of southern Poland. Acta Geologica Polonica, 63(4), 611-623. Warszawa. Lepidenteron lewesiensis (Mantell, 1822) is an unbranched trace fossil lined with small fish scales and bones, without a constructed wall. It is characteristic of the Upper Cretaceous epicontinental, mostly marly sediments in Europe. In the Miechow Segment of the Szczecin-Miechow Synclinorium in southern Poland, it occurs in the Upper Campanian-Lower Maastrichtian deeper shelf sediments, which were deposited below wave base and are characterized by total bioturbation and a trace fossil assemblage comprising Planolites, Palaeophycus, Thalassinoides , Trichichnus, Phycosiphon, Zoophycos and Helicodromites that is typical of the transition from the distal Cruziana to the Zoophycos ichnofacies. L. lewesiensis was produced by a burrowing predator or scavenger of fishes. The tracemaker candidates could be eunicid polychaetes or anguillid fishes.

Intial orbit determination results for Jason-1: towards a 1-cm orbit

NASA Technical Reports Server (NTRS)

Haines, B. J.; Haines, B.; Bertiger, W.; Desai, S.; Kuang, D.; Munson, T.; Reichert, A.; Young, L.; Willis, P.

2002-01-01

The U.S/France Jason-1 oceanographic mission is carrying state-of-the-art radiometric tracking systems (GPS and Doris) to support precise orbit determination (POD) requirements. The performance of the systems is strongly reflected in the early POD results. Results of both internal and external (e.g., satellite laser ranging) comparisons support that the 2.5 cm radial Rh4S requirement is being readily met, and provide reasons for optimism that 1 cm can be achieved. We discuss the POD strategy underlying these orbits, as well as the challenging issues that bear on the understanding and characterization of an orbit solution at the l-cm level. We also describe a system for producing science quality orbits in near real time in order to support emerging applications in operational oceanography.

Imaging the Danish Chalk Group with high resolution, 3-component seismics

NASA Astrophysics Data System (ADS)

Kammann, J.; Rasmussen, S. L.; Nielsen, L.; Malehmir, A.; Stemmerik, L.

2016-12-01

The Chalk Group in the Danish Basin forms important reservoirs to hydrocarbons as well as water resources, and it has been subject to several seismic studies to determine e.g. structural elements, deposition and burial history. This study focuses on the high quality seismic response of a survey acquired with an accelerated 45 kg weight drop and 3-component MEMS-based sensors and additional wireless vertical-type sensors. The 500 m long profile was acquired during one day close to a chalk quarry and chalk cliffs of the Stevns peninsula in eastern Denmark where the well-known K-T (Cretaceous-Tertiary) boundary and different chalk lithologies are well-exposed. With this simple and fast procedure we were able to achieve deep P-wave penetration to the base of the Chalk Group at about 900 m depth. Additionally, the CMP-processed seismic image of the vertical component stands out by its high resolution. Sedimentary features are imaged in the near-surface Danian, as well as in the deeper Maastrichtian and Upper Campanian parts of the Chalk Group. Integration with borehole data suggests that changes in composition, in particular clay content, correlate with changes in reflectivity of the seismic data set. While the pure chalk in the Maastrichtian deposits shows rather low reflectivity, succession enriched in clay appear to be more reflective. The integration of the mentioned methods gives the opportunity to connect changes in facies to the elastic response of the Chalk Group in its natural environmental conditions.

Thick-skinned tectonics in a Late Cretaceous-Neogene intracontinental belt (High Atlas Mountains, Morocco): The flat-ramp fault control on basement shortening and cover folding

NASA Astrophysics Data System (ADS)

Fekkak, A.; Ouanaimi, H.; Michard, A.; Soulaimani, A.; Ettachfini, E. M.; Berrada, I.; El Arabi, H.; Lagnaoui, A.; Saddiqi, O.

2018-04-01

Most of the structural studies of the intracontinental High Atlas belt of Morocco have dealt with the central part of the belt, whose basement does not crop out. Here we study the Alpine deformation of the North Subatlas Zone, which is the part of the Western High Atlas (WHA) Paleozoic Massif that involves both Paleozoic basement units and remnants of their Mesozoic-Cenozoic cover formations. Our aim is to better constrain the geometry and kinematics of the basement faults during the Alpine shortening. Based on detail mapping, satellite imagery and field observations, we describe an array of sub-equatorial, transverse and oblique faults between the WHA Axial Zone and the Haouz Neogene basin. They define a mosaic of basement blocks pushed upon one another and upon the Haouz basement along the North Atlas Fault (NAF). The Axial Zone makes up the hanging-wall of the Adassil-Medinet Fault (AMF) south of this mosaic. The faults generally presents flat-ramp-flat geometry linked to the activation of multiple décollement levels, either within the basement where its foliation is subhorizontal or within favourable cover formations (Jurassic evaporites, Lower Cretaceous silty red beds, Upper Cretaceous evaporitic marls, Neogene basal argillites). The occurrence of the North Atlas detachment (NAD) allowed folded pop-up units to develop in front of the propagating NAF. Shortening began as early as the Campanian-Maastrichtian along the AMF. The direction of the maximum horizontal stress rotated from NNE-SSW to NNW-SSE from the Maastrichtian-Paleocene to the Neogene. The amount of shortening reaches 20% in the Azegour transect. This compares with the shortening amount published for the central-eastern High Atlas, suggesting that similar structures characterize the Paleozoic basement all along the belt. The WHA thick-skinned tectonics evokes that of the frontal Sevier belt and of the external Western Alps, although with a much minor pre-inversion burial.

Early Phase Contingency Trajectory Design for the Failure of the First Lunar Orbit Insertion Maneuver: Direct Recovery Options

NASA Astrophysics Data System (ADS)

Song, Young-Joo; Bae, Jonghee; Kim, Young-Rok; Kim, Bang-Yeop

2017-12-01

To ensure the successful launch of the Korea pathfinder lunar orbiter (KPLO) mission, the Korea Aerospace Research Institute (KARI) is now performing extensive trajectory design and analysis studies. From the trajectory design perspective, it is crucial to prepare contingency trajectory options for the failure of the first lunar brake or the failure of the first lunar orbit insertion (LOI) maneuver. As part of the early phase trajectory design and analysis activities, the required time of flight (TOF) and associated delta-V magnitudes for each recovery maneuver (RM) to recover the KPLO mission trajectory are analyzed. There are two typical trajectory recovery options, direct recovery and low energy recovery. The current work is focused on the direct recovery option. Results indicate that a quicker execution of the first RM after the failure of the first LOI plays a significant role in saving the magnitudes of the RMs. Under the conditions of the extremely tight delta-V budget that is currently allocated for the KPLO mission, it is found that the recovery of the KPLO without altering the originally planned mission orbit (a 100 km circular orbit) cannot be achieved via direct recovery options. However, feasible recovery options are suggested within the boundaries of the currently planned delta-V budget. By changing the shape and orientation of the recovered final mission orbit, it is expected that the KPLO mission may partially pursue its scientific mission after successful recovery, though it will be limited.

Maastrichtian sedimentation and palaeoenvironments of the Saratov Volga region

NASA Astrophysics Data System (ADS)

Iakovishina, Elena; Blinova, Irina; Kopaevich, Ludmila; Vishnevskaya, Valentina; Bordunov, Sergey

2016-04-01

The Saratov Volga region was a shallow-marine epicontinental basin North-Eastern shelf zone of the Tethys Ocean in the Maastrichtian. The basis for the modeling conditions of sedimentation was the detection mineral composition of rocks, as well as the contents of various chemical elements in rocks in three reference sections: Lower Bannovka, quarries "Bolshevik" and "Kommunar". Rocks of quarries "Bolshevik" and "Kommunar" characterized by quartz-calcite mineral association. The main rock-forming mineral is calcite, small amounts in rocks contain quartz. Other mineral composition characterized section Lower Bannovka. At the base of the section in the rock marked the presence of the opal. The source of silica are radiolarians. Favorable conditions for the existence of which is cold deep water enriched with SiO2. Above the section marked authigenic glauconite, which are confined to zones of skip in sedimentation.Further up begins to dominate the accumulation of calcite with rich bentic foraminifera. Clay minerals in rocks of the section Lower Bannovka presented montmorillonite and illite. The relationship of chemical elements and their alkali modules allow to detail the conditions of sedimentation. The ratio of Fe/Mn in them varies from 44 to 5729. Higher values are characteristic of glauconite sandstones. Up the section marked decrease in the Ti/Zr, indicating that the increase in the distance from the source area to the place of deposition. The similarity values of the ratio Ti/Zr samples indicates a community source area. Sedimentation Model revealed the impact of the PreUral strait connecting Tethys and Paleoarktic. Through the Strait of deep cold water saturated with SiO2, penetrated into the of the Saratov Volga region, were accumulated clay. The closing of the PreUral Strait changed the conditions of sedimentation, the associated fall in sea levels due to global cooling reflected in the crisis of radiolarians, increase in the number of glauconite. Subsequent

A Centrosaurine (Dinosauria: Ceratopsia) from the Aguja Formation (Late Campanian) of Northern Coahuila, Mexico

PubMed Central

Rivera-Sylva, Héctor E.; Hedrick, Brandon P.; Dodson, Peter

2016-01-01

While centrosaurines and ceratopsids in general are abundant in the Late Campanian of northern Laramidia, they are much less commonly found in southern Laramidia. This has supported hypotheses of dinosaur provinciality and endemism in the Late Cretaceous with the delineation of at least two separate faunal zones, north and south Laramidia. There have been 12 genera of centrosaurines recognized from northern Laramidia while two genera, Diabloceratops and Nasutoceratops, have been named from southern Laramidia. We present an osteological description and taphonomic outline for a new centrosaurine ceratopsid from the Aguja Formation of northern Coahuila, Mexico that is not currently diagnosable to the generic level, but likely represents a new taxon. Further, we have included three-dimensional surface scans of all material attributed to this animal. Considering the large number of centrosaurines from northern Laramidia, it is likely that cladistic analyses are biased towards this faunal zone. New findings of southern centrosaurines are needed to correct this bias. This discovery expands the range of centrosaurines south to Coahuila, Mexico and adds new information to better characterize the morphology and taxonomy of centrosaurines from southern Laramidia and their evolution in comparison to their northern counterparts. PMID:27073969

A Centrosaurine (Dinosauria: Ceratopsia) from the Aguja Formation (Late Campanian) of Northern Coahuila, Mexico.

PubMed

Rivera-Sylva, Héctor E; Hedrick, Brandon P; Dodson, Peter

2016-01-01

While centrosaurines and ceratopsids in general are abundant in the Late Campanian of northern Laramidia, they are much less commonly found in southern Laramidia. This has supported hypotheses of dinosaur provinciality and endemism in the Late Cretaceous with the delineation of at least two separate faunal zones, north and south Laramidia. There have been 12 genera of centrosaurines recognized from northern Laramidia while two genera, Diabloceratops and Nasutoceratops, have been named from southern Laramidia. We present an osteological description and taphonomic outline for a new centrosaurine ceratopsid from the Aguja Formation of northern Coahuila, Mexico that is not currently diagnosable to the generic level, but likely represents a new taxon. Further, we have included three-dimensional surface scans of all material attributed to this animal. Considering the large number of centrosaurines from northern Laramidia, it is likely that cladistic analyses are biased towards this faunal zone. New findings of southern centrosaurines are needed to correct this bias. This discovery expands the range of centrosaurines south to Coahuila, Mexico and adds new information to better characterize the morphology and taxonomy of centrosaurines from southern Laramidia and their evolution in comparison to their northern counterparts.

Early Upper Paleolithic in Eastern Europe and implications for the dispersal of modern humans.

PubMed

Anikovich, M V; Sinitsyn, A A; Hoffecker, John F; Holliday, Vance T; Popov, V V; Lisitsyn, S N; Forman, Steven L; Levkovskaya, G M; Pospelova, G A; Kuz'mina, I E; Burova, N D; Goldberg, Paul; Macphail, Richard I; Giaccio, Biagio; Praslov, N D

2007-01-12

Radiocarbon and optically stimulated luminescence dating and magnetic stratigraphy indicate Upper Paleolithic occupation-probably representing modern humans-at archaeological sites on the Don River in Russia 45,000 to 42,000 years ago. The oldest levels at Kostenki underlie a volcanic ash horizon identified as the Campanian Ignimbrite Y5 tephra that is dated elsewhere to about 40,000 years ago. The occupation layers contain bone and ivory artifacts, including possible figurative art, and fossil shells imported more than 500 kilometers. Thus, modern humans appeared on the central plain of Eastern Europe as early as anywhere else in northern Eurasia.

Chapter 13 Petrogenesis of the Campanian Ignimbrite: implications for crystal-melt separation and open-system processes from major and trace elements and Th isotopic data

USGS Publications Warehouse

Bohrson, W.A.; Spera, F.J.; Fowler, S.J.; Belkin, H.E.; de Vivo, B.; Rolandi, G.

2006-01-01

The Campanian Ignimbrite is a large-volume trachytic to phonolitic ignimbrite that was deposited at ???39.3 ka and represents one of a number of highly explosive volcanic events that have occurred in the region near Naples, Italy. Thermodynamic modeling using the MELTS algorithm reveals that major element variations are dominated by crystal-liquid separation at 0.15 GPa. Initial dissolved H2O content in the parental melt is ???3 wt.% and the magmatic system fugacity of oxygen was buffered along QFM+1. Significantly, MELTS results also indicate that the liquid line of descent is marked by a large change in the proportion of melt (from 0.46 to 0.09) at ???884??C, which leads to a discontinuity in melt composition (i.e., a compositional gap) and different thermodynamic and transport properties of melt and magma across the gap. Crystallization of alkali feldspar and plagioclase dominates the phase assemblage at this pseudo-invariant point temperature of ???884??C. Evaluation of the variations in the trace elements Zr, Nb, Th, U, Rb, Sm, and Sr using a mass balance equation that accounts for changing bulk mineral-melt partition coefficients as crystallization occurs indicates that crystal-liquid separation and open-system processes were important. Th isotope data yield an apparent isochron that is ???20 kyr younger than the age of the deposit, and age-corrected Th isotope data indicate that the magma body was an open system at the time of eruption. Because open-system behavior can profoundly change isotopic and elemental characteristics of a magma body, these Th results illustrate that it is critical to understand the contribution that open-system processes make to magmatic systems prior to assigning relevance to age or timescale information derived from such systems. Fluid-magma interaction has been proposed as a mechanism to change isotopic and elemental characteristics of magma bodies, but an evaluation of the mass and thermal constraints on such a process suggests

Orbital- to Sub-Orbital-Scale Cyclicity in Seismic Reflections and Sediment Character in Early to Middle Pleistocene Mudstone, Santa Barbara Basin, California

NASA Astrophysics Data System (ADS)

Peterson, C. D.; Behl, R. J.; Nicholson, C.; Lisiecki, L. E.; Sorlien, C. C.

2009-12-01

High-resolution seismic reflection records and well logs from the Santa Barbara Channel suggest that large parts of the Pleistocene succession records climate variability on orbital to sub-orbital scales with remarkable sensitivity, much like the well-studied sediments of the last glacial cycle (ODP Site 893). Spectral analysis of seismic reflection data and gamma ray logs from stratigraphically similar Pleistocene sections finds similar cyclic character and shifts through the section. This correlation suggests that acoustic impedance and physical properties of sediment are linked by basin-scale, likely climatically-driven, oscillations in lithologic composition and fabric during deposition, and that seismic profiling can provide a method for remote identification and correlation of orbital- and sub-orbital-scale sedimentary cyclicity. Where it crops out along the northern shelf of the central Santa Barbara Channel, the early to middle Pleistocene succession (~1.8-1.2 Ma) is a bathyal hemipelagic mudstone with remarkably rhythmic planar bedding, finely laminated fabric, and well-preserved foraminifera, none of which have been significantly altered, or obscured by post-depositional diagenesis or tectonic deformation. Unlike the coarser, turbiditic successions in the central Ventura and Los Angeles basins, this sequence has the potential to record Quaternary global climate change at high resolution. Seismic reflection data (towed chirp) collected on the R/V Melville 2008 Cruise (MV08) penetrate 10's of meters below seafloor into a ~1 km-long sequence of south-dipping seismic reflectors. Sampling parallel to the seafloor permits acquisition of consistent signal amplitude for similar reflectors without spreading loss. Based on established age ranges for this section, sedimentation rates may range from 0.4 to 1.4 meters/kyr, therefore suggesting that the most powerful cycles are orbital- to sub-orbital-scale. Discrete sets of cycles with high power show an abrupt shift

The Mars Reconnaissance Orbiter Mission: From Launch to the Primary Science Orbit

NASA Technical Reports Server (NTRS)

Johnston, Martin D.; Graf, James E.; Zurek, Richard W.; Eisen, Howard J.; Jai, Benhan; Erickson, James K.

2007-01-01

The Mars Reconnaissance Orbiter (MRO) was launched from Cape Canaveral Air Force Station, Florida, USA, aboard an Atlas V-401 launch vehicle on August 12, 2005. The MRO spacecraft carries a very sophisticated scientific payload. Its primary science mission is to to provide global, regional survey, and targeted observations from a low altitude orbit for one Martian year (687 Earth days). After a seven month interplanetary transit, the spacecraft fired its six main engines and established a highly elliptical capture orbit at Mars. During the post-MOI early check-out period, four instruments acquired engineering-quality data. This was followed by five months of aerobraking operations. After aerobraking was terminated, a series of propulsive maneuvers were used to establish the desired low altitude science orbit. As the spacecraft is readied for its primary science mission, spacecraft and instrument checkout and deployment activities have continued.

The status of organochlorine pesticide contamination in the soils of the Campanian Plain, southern Italy, and correlations with soil properties and cancer risk.

PubMed

Qu, Chengkai; Albanese, Stefano; Chen, Wei; Lima, Annamaria; Doherty, Angela L; Piccolo, Alessandro; Arienzo, Michele; Qi, Shihua; De Vivo, Benedetto

2016-09-01

The distribution, inventory, and potential risk of organochlorine pesticides (OCPs), including Hexachlorocyclohexanes (HCHs) and Dichlorodiphenyltrichloroethanes (DDTs), and their correlation with soil properties and anthropogenic factors were investigated in soils of the Campanian Plain. The total concentrations of HCHs and DDTs ranged from 0.03 to 17.3 ng/g (geometric mean: GM = 0.05 ng/g), and 0.08-1231 ng/g (GM = 14.4 ng/g), respectively. In general, the concentration of OCPs in farmland and orchards was higher than on land used for non-agricultural purposes. There are significant differences in the concentration of OCPs in the soils across the region, more specifically, the Acerra-Marigliano conurbation (AMC) and Sarno River Basin (SRB) are recognized as severely OCP-contaminated areas. The recent application of technical HCHs and DDTs in large quantities appears unlikely in light of the ratio of α-HCH/β-HCH and p,p'-DDT/p,p'-DDE, and the prohibition of the use of these chemicals in Italy nearly forty years ago. The clear correlation between the concentration of DDTs and organic carbon suggests a typical secondary distribution pattern. The mass inventory of OCPs in soils of the Campanian Plain is estimated to have a GM of 17.3 metric tons. There is no clear evidence linking the impact of geographical distribution of OCPs on the incidence of cancer, and the 95% confidence interval of total incremental lifetime cancer risk (TILCR) data falls below the internationally accepted benchmark value of 1 × 10(-5). Copyright © 2016 Elsevier Ltd. All rights reserved.

A ‘Terror of Tyrannosaurs’: The First Trackways of Tyrannosaurids and Evidence of Gregariousness and Pathology in Tyrannosauridae

PubMed Central

McCrea, Richard T.; Buckley, Lisa G.; Farlow, James O.; Lockley, Martin G.; Currie, Philip J.; Matthews, Neffra A.; Pemberton, S. George

2014-01-01

The skeletal record of tyrannosaurids is well-documented, whereas their footprint record is surprisingly sparse. There are only a few isolated footprints attributed to tyrannosaurids and, hitherto, no reported trackways. We report the world’s first trackways attributable to tyrannosaurids, and describe a new ichnotaxon attributable to tyrannosaurids. These trackways are from the Upper Cretaceous (Campanian - Maastrichtian) of northeastern British Columbia, Canada. One trackway consists of three tridactyl footprints, and two adjacent trackways consist of two footprints each. All three trackways show animals bearing southeast within an 8.5 meter-wide corridor. Similarities in depth and preservation of the tyrannosaurid tracks indicate that these three trackways were made by track-makers walking concurrently in the same direction. These trackways add significantly to previous osteology-based hypotheses of locomotion and behavior in Tyrannosauridae by providing ichnologic support for gregariousness in tyrannosaurids, and the first record of the walking gait of tyrannosaurids. PMID:25054328

Shelf architectures of an isolated Late Cretaceous carbonate platform margin, Galala Mountains (Eastern Desert, Egypt)

NASA Astrophysics Data System (ADS)

Scheibner, C.; Marzouk, A. M.; Kuss, J.

2001-12-01

An asymmetrical carbonate platform margin to basin transect has been investigated in the Upper Campanian-Maastrichtian succession of the Galala Mountains, northern Egypt. Identification of systems tracts and their lateral correlation was possible in slope sections only, whereas the monotonous chalk-marl alternations of the basinal sections could not be subdivided with respect to sequence stratigraphic terminology. The platform asymmetry is expressed by varying large-scale depositional architectures exhibiting a rimmed platform with a sigmoidal slope curvature in south-easterly dip-sections and a ramp with a linear slope curvature in south-westerly dip-sections. The rimmed platform is subdivided into a gentle upper slope and a steep lower slope. The platform formed as a result of the initial topography that was controlled by the tectonic uplift of the Northern Galala/Wadi Araba Syrian Arc structure. The calculated angles of the steep lower slope of the rimmed part range from 5 to 8°, whereas the ramp part has an angle of less than 0.1°.

Man-Made Debris In and From Lunar Orbit

NASA Technical Reports Server (NTRS)

Johnson, Nicholas L.; McKay, Gordon A. (Technical Monitor)

1999-01-01

During 1966-1976, as part of the first phase of lunar exploration, 29 manned and robotic missions placed more than 40 objects into lunar orbit. Whereas several vehicles later successfully landed on the Moon and/or returned to Earth, others were either abandoned in orbit or intentionally sent to their destruction on the lunar surface. The former now constitute a small population of lunar orbital debris; the latter, including four Lunar Orbiters and four Lunar Module ascent stages, have contributed to nearly 50 lunar sites of man's refuse. Other lunar satellites are known or suspected of having fallen from orbit. Unlike Earth satellite orbital decays and deorbits, lunar satellites impact the lunar surface unscathed by atmospheric burning or melting. Fragmentations of lunar satellites, which would produce clouds of numerous orbital debris, have not yet been detected. The return to lunar orbit in the 1990's by the Hagoromo, Hiten, Clementine, and Lunar Prospector spacecraft and plans for increased lunar exploration early in the 21st century, raise questions of how best to minimize and to dispose of lunar orbital debris. Some of the lessons learned from more than 40 years of Earth orbit exploitation can be applied to the lunar orbital environment. For the near-term, perhaps the most important of these is postmission passivation. Unique solutions, e.g., lunar equatorial dumps, may also prove attractive. However, as with Earth satellites, debris mitigation measures are most effectively adopted early in the concept and design phase, and prevention is less costly than remediation.

Observations from Juno's Radiation Monitoring Investigation during Juno's Early Orbits

NASA Astrophysics Data System (ADS)

Becker, Heidi N.; Jorgensen, John L.; Adriani, Alberto; Mura, Alessandro; Connerney, John E. P.; Santos-Costa, Daniel; Bolton, Scott J.; Levin, Steven M.; Alexander, James W.; Adumitroaie, Virgil; Manor-Chapman, Emily A.; Daubar, Ingrid J.; Lee, Clifford; Benn, Mathias; Denver, Troelz; Sushkova, Julia; Cicchetti, Andrea; Noschese, Raffaella; Thorne, Richard M.

2017-04-01

Juno's Radiation Monitoring (RM) Investigation profiles Jupiter's >10-MeV electron environment throughout unexplored regions of the Jovian magnetosphere. RM's measurement approach involves active retrieval of the characteristic noise signatures from penetrating radiation in images obtained by Juno's heavily shielded star cameras and science instruments. Collaborative observation campaigns of "radiation image" collection and penetrating particle counts are conducted at targeted opportunities within the magnetosphere during each of Juno's perijove passes using the spacecraft Stellar Reference Unit, the Magnetic Field Investigation's Advanced Stellar Compass Imagers, and the JIRAM infrared imager. Simultaneous observations gathered from these very different instruments provide comparative spectral information due to substantial differences in instrument shielding. Juno's orbit provides a unique sampling of energetic particles within Jupiter's innermost radiation belts and polar regions. We present a survey of observations of the high energy radiation environment made by Juno's SRU and ASC star cameras and the JIRAM infrared imager during Juno's early perijove passes on August 27 and December 11, 2016; and February 2 and March 27, 2017. The JPL author's copyright for this publication is held by the California Institute of Technology. Government Sponsorship acknowledged.

Quantifying distal dispersal and impact of volcanic ash from super-eruptions: an application to Campanian Ignimbrite

NASA Astrophysics Data System (ADS)

Costa, A.; Folch, A.; Macedonio, G.; Giaccio, B.; Isaia, R.; Smith, V. C.

2012-04-01

Distal and ultra-distal volcanic ash dispersal during a super-eruption was reconstructed for the first time, providing insights into eruption dynamics and the impact of these gigantic events. A novel computational methodology was applied to the ash fallout of the Campanian Ignimbrite (CI), the most powerful volcanic eruption in Europe in the last 200 kyrs. The method uses a 3D time-dependent computational ash dispersion model, an ensemble of wind fields, and hundreds of thickness observations of the CI tephra deposit. Results reveal that 250-300 km3 of fallout material was produced during the eruption, blanketing a region of ~3.7 million km2 with more than 5 mm of fine ash. The model also indicates that the column height was ~37-40 km, and the eruption lasted 2-4 days. The eruption would have caused a volcanic winter within the coldest and driest Heinrich event. Fluorine-bearing leachate from the volcanic ash and acid rain would have further affected food sources and severely impacted Late Middle Paleolithic groups in Southern and Eastern Europe.

Seismic stratigraphy, tectonics and depositional history in the Halk el Menzel region, NE Tunisia

NASA Astrophysics Data System (ADS)

Sebei, Kawthar; Inoubli, Mohamed Hédi; Boussiga, Haïfa; Tlig, Said; Alouani, Rabah; Boujamaoui, Mustapha

2007-01-01

In the Halk el Menzel area, the proximal- to pelagic platform transition and related tectonic events during the Upper Cretaceous-Lower Miocene have not been taken into adequate consideration. The integrated interpretation of outcrop and subsurface data help define a seismic stratigraphic model and clarify the geodynamic evolution of the Halk el Menzel block. The sedimentary column comprises marls and limestones of the Campanian to Upper Eocene, overlain by Oligocene to Lower Miocene aged siliciclastics and carbonates. Well to well correlations show sedimentary sequences vary considerably in lithofacies and thicknesses over short distances with remarkable gaps. The comparison of sedimentary sequences cut by borehole and seismic stratigraphic modelling as well help define ten third order depositional sequences (S1-S10). Sequences S1 through S6 (Campanian-Paleocene) are mainly characterized by oblique to sigmoid configurations with prograding sedimentary structures, whereas, sequences S7-S10 (Ypresian to Middle Miocene) are organized in shallow water deposits with marked clinoform ramp geometry. Sedimentary discontinuities developed at sequence boundaries are thought to indicate widespread fall in relative sea level. Angular unconformities record a transpressive tectonic regime that operated from the Campanian to Upper Eocene. The geometry of sequences with reduced thicknesses, differential dipping of internal seismic reflections and associated normal faulting located westerly in the area, draw attention to a depositional sedimentary system developed on a gentle slope evolving from a tectonically driven steepening towards the Northwest. The seismic profiles help delimit normal faulting control environments of deposition. In contrast, reef build-ups in the Eastern parts occupy paleohighs NE-SW in strike with bordering Upper Maastrichtian-Ypresian seismic facies onlapping Upper Cretaceous counterparts. During the Middle-Upper Eocene, transpressive stress caused

Toward an orbital chronology for the early Aptian Oceanic Anoxic Event (OAE1a, ~ 120 Ma)

NASA Astrophysics Data System (ADS)

Li, Yong-Xiang; Bralower, Timothy J.; Montañez, Isabel P.; Osleger, David A.; Arthur, Michael A.; Bice, David M.; Herbert, Timothy D.; Erba, Elisabetta; Premoli Silva, Isabella

2008-07-01

The early Aptian Oceanic Anoxic Event (OAE1a, 120 Ma) represents a geologically brief time interval in the mid-Cretaceous greenhouse world that is characterized by increased organic carbon accumulation in marine sediments, sudden biotic changes, and abrupt carbon-isotope excursions indicative of significant perturbations to global carbon cycling. The brevity of these drastic environmental changes (< 10 6 year) and the typically 10 6 year temporal resolution of the available chronologies, however, represent a critical gap in our knowledge of OAE1a. We have conducted a high-resolution investigation of three widely distributed sections, including the Cismon APTICORE in Italy, Santa Rosa Canyon in northeastern Mexico, and Deep Sea Drilling Project (DSDP) Site 398 off the Iberian margin in the North Atlantic Ocean, which represent a range of depositional environments where condensed and moderately expanded OAE1a intervals are recorded. The objectives of this study are to establish orbital chronologies for these sections and to construct a common, high-resolution timescale for OAE1a. Spectral analyses of the closely-spaced (corresponding to ~ 5 to 10 kyr) measurements of calcium carbonate content of the APTICORE, magnetic susceptibility (MS) and anhysteretic remanent magnetization (ARM) of the Santa Rosa samples, and MS, ARM and ARM/IRM, where IRM is isothermal remanent magnetization, of Site 398 samples reveal statistically significant cycles. These cycles exhibit periodicity ratios and modulation patterns similar to those of the mid-Cretaceous orbital cycles, suggesting that orbital variations may have modulated depositional processes. Orbital control allows us to estimate the duration of unique, globally identifiable stages of OAE1a. Although OAE1a had a duration of ~ 1.0 to 1.3 Myr, the initial perturbation represented by the negative carbon-isotope excursion was rapid, lasting for ~ 27-44 kyr. This estimate could serve as a basis for constraining triggering

On-orbit checkout of satellites, volume 2. Part 3 of on-orbit checkout study. [space maintenance

NASA Technical Reports Server (NTRS)

Pritchard, E. I.

1978-01-01

Early satellite failures significantly degrading satellite operations are reviewed with emphasis on LANDSAT D, the Technology Demonstration Satellite, the ATREX/AEM spacecraft, STORMSAT 2, and the synchronous meteorological satellite. Candidates for correction with on-orbit checkout and appropriate actions are analyzed. On-orbit checkout subsystem level studies are summarized for electrical power, attitude control, thermal control, reaction control and propulsion, instruments, and angular rate matching for alignment of satellite IRU.

Early Program Development

NASA Image and Video Library

1971-01-01

This 1971 artist's concept shows a Nuclear Shuttle and an early Space Shuttle docked with an Orbital Propellant Depot. As envisioned by Marshall Space Flight Center Program Development persornel, an orbital modular propellant storage depot, supplied periodically by the Space Shuttle or Earth-to-orbit fuel tankers, would be critical in making available large amounts of fuel to various orbital vehicles and spacecraft.

PHOTOMETRIC, SPECTROSCOPIC, AND ORBITAL PERIOD STUDY OF THREE EARLY-TYPE SEMI-DETACHED SYSTEMS: XZ AQL, UX HER, AND AT PEG

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zola, S.; Baştürk, Ö.; Şenavcı, H. V.

2016-08-01

In this paper, we present a combined photometric, spectroscopic, and orbital period study of three early-type eclipsing binary systems: XZ Aql, UX Her, and AT Peg. As a result, we have derived the absolute parameters of their components and, on that basis, we discuss their evolutionary states. Furthermore, we compare their parameters with those of other binary systems and with theoretical models. An analysis of all available up-to-date times of minima indicated that all three systems studied here show cyclic orbital changes; their origin is discussed in detail. Finally, we performed a frequency analysis for possible pulsational behavior, and asmore » a result we suggest that XZ Aql hosts a δ Scuti component.« less

Detailed measured sections, cross sections, and paleogeographic reconstructions of the upper cretaceous and lower tertiary nonmarine interval, Wind River Basin, Wyoming: Chapter 10 in Petroleum systems and geologic assessment of oil and gas resources in the Wind River Basin Province, Wyoming

USGS Publications Warehouse

Johnson, Ronald C.

2007-01-01

Detailed measured sections and regional stratigraphic cross sections are used to reconstruct facies maps and interpret paleogeographic settings for the interval from the base of Upper Cretaceous Mesaverde Formation to top of lower member of the Paleocene Fort Union Formation in the Wind River Basin, Wyoming. The Mesaverde Formation spans the time during which the Upper Cretaceous seaway retreated eastward out of central Wyoming in Campanian time and the initial stages of the Lewis transgression in earliest Maastrichtian time. This retreat stalled for a considerable period of time during deposition of the lower part of the Mesaverde, creating a thick buildup of marginal marine sandstones and coaly coastal plain deposits across the western part of the basin. The Lewis sea transgressed into the northeast part of Wind River Basin, beginning in early Maastrichtian time during deposition of the Teapot Sandstone Member of the Mesaverde Formation. The Meeteetse Formation, which overlies the Teapot, was deposited in a poorly-drained coastal plain setting southwest of the Lewis seaway. The Lewis seaway, at maximum transgression, covered much of the northeast half of the Wind River Basin area but was clearly deflected around the present site of the Wind River Range, southwest of the basin, providing the first direct evidence of Laramide uplift on that range. Uplift of the Wind River Range continued during deposition of the overlying Maastrichtian Lance Formation. The Granite Mountains south of the basin also became a positive feature during this time. A rapidly subsiding trough during the Maastrichtian time formed near the presentday trough of the Wind River Basin in which more than 6,000 feet of Lance was deposited. The development of this trough appears to have begun before the adjacent Owl Creek Mountains to the north started to rise; however, a muddy facies in the upper part of Lance in the deep subsurface, just to the south, might be interpreted to indicate that the

A new species of Allodaposuchus (Eusuchia, Crocodylia) from the Maastrichtian (Late Cretaceous) of Spain: phylogenetic and paleobiological implications

PubMed Central

Blanco, Alejandro; Fortuny, Josep; Vicente, Alba; Luján, Àngel H.; García-Marçà, Jordi Alexis

2015-01-01

Background. The Late Cretaceous is a keystone period to understand the origin and early radiation of Crocodylia, the group containing all extant lineages of crocodilians. Among the taxa described from the latest Cretaceous of Europe, the genus Allodaposuchus is one of the most common but also one of the most controversial. However, because of its fragmentary record, several issues regarding its phylogenetic emplacement and its ecology remain unsolved or unknown. The discovery of a single specimen attributed to Allodaposuchus, represented by both cranial and postcranial remains, from the Casa Fabà site (Tremp Basin, NE Spain) in the lower red unit of the Tremp Fm. (early Maastrichtian, Late Cretaceous) offers a unique opportunity to deepen in the phylogenetic relationships of the group and its ecological features. Methods. The specimen is described in detail, and CT scan of the skull is performed in order to study the endocranial morphology as well as paratympanic sinuses configuration. In addition, myological and phylogenetic analyses are also carried out on the specimen for to shed light in ecological and phylogenetic issues, respectively. Results. The specimen described herein represents a new species, Allodaposuchus hulki sp. nov., closely related to the Romanian A. precedens. The CT scan of the skull revealed an unexpected paratympanic sinuses configuration. Allosaposuchus hulki exhibits an “anterodorsal tympanic sinus” not observed in any other extant or extinct crocodilian. The caudal tympanic recesses are extremely enlarged, and the expanded quadratic sinus seems to be connected to the middle-ear channel. Phylogenetic analyses confirm the emplacement of the informal taxonomic group ‘Allodaposuchia’ at the base of Crocodylia, being considered the sister group of Borealosuchus and Planocraniidae. Discussion. Although this is a preliminary hypothesis, the unique paratympanic configuration displayed by A. hulki suggests that it could possess a high

New Insights into Early Cenozoic Carbon Cycling: Continental Ecosystem Response to Orbital Forcing in the Lacustrine Green River Formation (Western US) at the Conclusion of the Early Eocene Climatic Optimum

NASA Astrophysics Data System (ADS)

Musher, D.; Grogan, D. S.; Whiteside, J. H.

2010-12-01

A series of extreme warming events, known as hyperthermals, interrupted the equable climate conditions predominant during the early Cenozoic hothouse. In marine sediments, these hyperthermals are marked by prominent negative carbon isotope excursions, indicative of dramatic and abrupt changes in the global exogenic carbon pool, as well as carbonate dissolution horizons and benthic foraminiferal extinctions. Hyperthermals are well documented in the marine record, but it is less clear how patterns of global carbon cycling manifested in early Cenozoic terrestrial environments, although some studies have documented amplified excursions relative to that of the marine record. The lacustrine Eocene Green River Formation of Utah is an excellent system for studying the continental environmental context of global carbon cycle dynamics during this time. These sediments span a ~15 Myr time interval, including the entire Early Eocene Climatic Optimum (EECO) and the transition to the long-term Cenozoic cooling trend. To investigate the relationship between the continental carbon record and global carbon cycling, climate, and orbital forcing, we studied a detailed section from the P-4 core drilled in the Uinta Basin bracketing the famous “Mahogany Bed”, a petroliferous layer of oil shale recording a period of enhanced productivity and carbon burial near the end of the EECO. Our carbon isotope measurements of high molecular weight n-alkanes across this boundary suggest a stable global carbon cycle and climate regime persisting ~400 kyr at the terminal EECO. Frequency spectra of published oil yield and gamma ray data from this section reveal concentrated power at Milankovitch frequencies, permitting the assembly of a robust age model. In concert with radioisotopic age control, our orbital chronology allows for comparison of our carbon cycle record to early Eocene astronomical solutions. We show that the Mahogany Bed corresponds to strong minima in short and long eccentricity

Latest Cretaceous Climatic and Environmental Change in the South Atlantic Region

NASA Astrophysics Data System (ADS)

Woelders, L.; Vellekoop, J.; Smit, J.; Kroon, D.; Casadío, S.; Prámparo, M.; Dinarès-turell, J.; Peterse, F.; Sluijs, A.; Speijer, R. P.

2016-12-01

It is generally assumed that the Chicxulub impact resulted in the Cretaceous-Paleogene (K-Pg) boundary mass extinction ( 66 Ma). However, there is continuing debate about the contribution of latest Maastrichtian climate changes, possibly caused by Deccan volcanism, to this mass extinction event. This debate is complicated because of the lack of high quality latest Maastrichtian climatological and ecological reconstructions. Here we present an astronomically tuned late Maastrichtian - early Danian record of bulk carbonate δ18O, a proxy record of sea surface temperature (SST), from Southern Atlantic Ocean Drilling Program Site 1262 (Walvis Ridge) and a late Maastrichtian TEX86 sea surface temperature record from the Bajada del Jagüel site in the Neuquén Basin (Argentina). The combination of these inferred temperature records with foraminiferal and organic-walled dinoflagellate cyst (dinocyst) data from Bajada del Jagüel allows to reconstruct environmental changes across this time interval in a mid-latitude, Southern Atlantic setting. Our results show that latest Maastrichtian warming of 2.5-4°C started gradually around 66.7 Ma, culminating in the interval between 450 to 150 kyr before the K-Pg boundary. Highest temperatures occurred 200 kyr before the K-Pg boundary. During the last 150 kyr of the Maastrichtian, the temperature trend reversed again at both sites. Benthic foraminiferal and dinocyst assemblage changes indicate that late Maastrichtian warming resulted in more humid climate conditions in the Neuquén basin, causing enhanced runoff and stratification of the water column. Vice versa, the subsequent cooling induced again a drier climate in the basin, resulting in reduced salinity stratification and better ventilation of the basin. We conclude that late Maastrichtian climate and sea level change caused distinct environmental perturbations in the Neuquén basin, although it remains uncertain to which extent late Maastrichtian climatological changes

Early In-orbit Performance of Scanning Sky Monitor Onboard AstroSat

NASA Astrophysics Data System (ADS)

Ramadevi, M. C.; Ravishankar, B. T.; Sitaramamurthy, N.; Meena, G.; Singh, Brajpal; Jain, Anand; Yadav, Reena; Agarwal, Anil; Babu, V. Chandra; Kumar; Kushwaha, Ankur; Vaishali, S.; Iyer, Nirmal Kumar; Nandi, Anuj; Girish, V.; Agarwal, Vivek Kumar; Seetha, S.; Bhattacharya, Dipankar; Balaji, K.; Kumar, Manoj; Kulshresta, Prashanth

2017-06-01

We report the in-orbit performance of Scanning Sky Monitor (SSM) onboard AstroSat. The SSM operates in the energy range 2.5 to 10 keV and scans the sky to detect and locate transient X-ray sources. This information of any interesting phenomenon in the X-ray sky as observed by SSM is provided to the astronomical community for follow-up observations. Following the launch of AstroSat on 28th September, 2015, SSM was commissioned on October 12th, 2015. The first power ON of the instrument was with the standard X-ray source, Crab in the field-of-view. The first orbit data revealed the basic expected performance of one of the detectors of SSM, SSM1. Following this in the subsequent orbits, the other detectors were also powered ON to find them perform in good health. Quick checks of the data from the first few orbits revealed that the instrument performed with the expected angular resolution of 12' × 2.5° and effective area in the energy range of interest. This paper discusses the instrument aspects along with few on-board results immediately after power ON.

Early Program Development

NASA Image and Video Library

1970-01-01

This artist's concept from 1970 shows a Nuclear Shuttle docked to an Orbital Propellant Depot and an early Space Shuttle. As envisioned by Marshall Space Flight Center Program Development plarners, the Nuclear Shuttle, in either manned or unmanned mode, would deliver payloads to lunar orbit or other destinations then return to Earth orbit for refueling and additonal missions.

Orbiter Docking System Installation

NASA Technical Reports Server (NTRS)

1995-01-01

Workers in Orbiter Processing Facility Bay 3 are installing the Orbiter Docking System (ODS) in the payload bay of the orbiter Atlantis (OV-104). The ODS includes an airlock, a supporting truss structure, a docking base, and a Russian-built docking mechanism (uppermost). The ODS is nearly 15 feet (4.6 meters) wide, 6.5 feet (2 meters) long, 13.5 feet (4.1 meters high), and weighs more than 3,500 pounds (1,588 kilograms). It is being installed near the forward end of the orbiter's payload bay and will be connected by a short tunnel to the existing airlock inside the orbiter's pressurized crew cabin.The installation will take about two hours to complete. Later this week, the Spacelab module also will be installed in OV-104's payload bay; it will connect to the ODS via a tunnel. During the first docking between the Space Shuttle Atlantis and the Russian Space Station Mir, the Russian-built docking mechanism on the ODS will be mated to a similar interface on the Krystall module docking port on Mir, allowing crew members to pass back and forth between the two spacecraft. That Shuttle mission, STS-71, is scheduled for liftoff in early June.

Application of [sup 87]Sr/[sup 86]Sr, [delta][sup 18]O and [delta][sup 13]C isotopes to diagenesis correlation and connectivity of a fractured chalk reservoir, the Sidi El Kilani field, Tunisia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mearns, E.W.; McBride, J.J.; Bramwell, M.

1996-01-01

Oil is produced primarily from open fracture porosity in Upper Cretaceous chalk in the Sidi El Kilani oil field. Strontium Stratigraphy analyses of primary, unaltered matrix chalk has confirmed a Campanian to Maastrichtian age and has allowed dating of the reservoir with a resolution of [+-]1 Ma. This has facilitated reservoir correlation and has indicated where section is missing in certain wells due to faulting. [sup 87]Sr/[sup 86]Sr, [delta][sup 18]O and [delta][sup 13]C analyses suggest an early generation of fracture fill calcite cement may have formed by redistribution of CaCO[sub 3] from underlying carbonate sequences at temperatures in the regionmore » 35-55[degrees]C. Calcite cemented fractures tend to be healed and are not productive. Strontium Isotope Residual Salt Analyses (SrRSA) conducted on core, provide information on the formation water chemistry and reservoir connectivity at the time of oil filling. These data suggest that the NW-SE trending fault system that bisects the field is sealed across much of the fault plane. The main oil pool lies SW of the fault. A later generation of dolomite and barite cements, associated with productive open fractures, have Sr-O-C composition consistent with precipitation from fluids circulating at the time of hydrocarbon charge at temperatures close to current reservoir conditions of 70-75[degrees]C. Predicting the distribution of dolomite cemented open fractures has thus helped guide the development strategy of the field.« less

Application of {sup 87}Sr/{sup 86}Sr, {delta}{sup 18}O and {delta}{sup 13}C isotopes to diagenesis correlation and connectivity of a fractured chalk reservoir, the Sidi El Kilani field, Tunisia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mearns, E.W.; McBride, J.J.; Bramwell, M.

1996-12-31

Oil is produced primarily from open fracture porosity in Upper Cretaceous chalk in the Sidi El Kilani oil field. Strontium Stratigraphy analyses of primary, unaltered matrix chalk has confirmed a Campanian to Maastrichtian age and has allowed dating of the reservoir with a resolution of {+-}1 Ma. This has facilitated reservoir correlation and has indicated where section is missing in certain wells due to faulting. {sup 87}Sr/{sup 86}Sr, {delta}{sup 18}O and {delta}{sup 13}C analyses suggest an early generation of fracture fill calcite cement may have formed by redistribution of CaCO{sub 3} from underlying carbonate sequences at temperatures in the regionmore » 35-55{degrees}C. Calcite cemented fractures tend to be healed and are not productive. Strontium Isotope Residual Salt Analyses (SrRSA) conducted on core, provide information on the formation water chemistry and reservoir connectivity at the time of oil filling. These data suggest that the NW-SE trending fault system that bisects the field is sealed across much of the fault plane. The main oil pool lies SW of the fault. A later generation of dolomite and barite cements, associated with productive open fractures, have Sr-O-C composition consistent with precipitation from fluids circulating at the time of hydrocarbon charge at temperatures close to current reservoir conditions of 70-75{degrees}C. Predicting the distribution of dolomite cemented open fractures has thus helped guide the development strategy of the field.« less

Spiral Orbit Tribometer

NASA Technical Reports Server (NTRS)

Pepper, Stephen V.; Jones, William R., Jr.; Kingsbury, Edward; Jansen, Mark J.

2007-01-01

The spiral orbit tribometer (SOT) bridges the gap between full-scale life testing and typically unrealistic accelerated life testing of ball-bearing lubricants in conjunction with bearing ball and race materials. The SOT operates under realistic conditions and quickly produces results, thereby providing information that can guide the selection of lubricant, ball, and race materials early in a design process. The SOT is based upon a simplified, retainerless thrust bearing comprising one ball between flat races (see figure). The SOT measures lubricant consumption and degradation rates and friction coefficients in boundary lubricated rolling and pivoting contacts. The ball is pressed between the lower and upper races with a controlled force and the lower plate is rotated. The combination of load and rotation causes the ball to move in a nearly circular orbit that is, more precisely, an opening spiral. The spiral s pitch is directly related to the friction coefficient. At the end of the orbit, the ball contacts the guide plate, restoring the orbit to its original radius. The orbit is repeatable throughout the entire test. A force transducer, mounted in-line with the guide plate, measures the force between the ball and the guide plate, which directly relates to the friction coefficient. The SOT, shown in the figure, can operate in under ultra-high vacuum (10(exp -9) Torr) or in a variety of gases at atmospheric pressure. The load force can be adjusted between 45 and 450 N. By varying the load force and ball diameter, mean Hertzian stresses between 0.5 and 5.0 GPa can be obtained. The ball s orbital speed range is between 1 and 100 rpm.

Orbit Determination and Navigation of the Time History of Events and Macroscale Interactions during Substorms (THEMIS)

NASA Technical Reports Server (NTRS)

Morinelli, Patrick; Cosgrove, Jennifer; Blizzard, Mike; Robertson, Mike

2007-01-01

This paper provides an overview of the launch and early orbit activities performed by the NASA Goddard Space Flight Center's (GSFC) Flight Dynamics Facility (FDF) in support of five probes comprising the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft. The FDF was tasked to support THEMIS in a limited capacity providing backup orbit determination support for validation purposes for all five THEMIS probes during launch plus 30 days in coordination with University of California Berkeley Flight Dynamics Center (UCB/FDC)2. The FDF's orbit determination responsibilities were originally planned to be as a backup to the UCB/FDC for validation purposes only. However, various challenges early on in the mission and a Spacecraft Emergency declared thirty hours after launch placed the FDF team in the role of providing the orbit solutions that enabled contact with each of the probes and the eventual termination of the Spacecraft Emergency. This paper details the challenges and various techniques used by the GSFC FDF team to successfully perform orbit determination for all five THEMIS probes during the early mission. In addition, actual THEMIS orbit determination results are presented spanning the launch and early orbit mission phase. Lastly, this paper enumerates lessons learned from the THEMIS mission, as well as demonstrates the broad range of resources and capabilities within the FDF for supporting critical launch and early orbit navigation activities, especially challenging for constellation missions.

Orbit Determination and Navigation of the Time History of Events and Macroscale Interactions during Substorms (THEMIS)

NASA Technical Reports Server (NTRS)

Morinelli, Patrick; Cosgrove, jennifer; Blizzard, Mike; Nicholson, Ann; Robertson, Mika

2007-01-01

This paper provides an overview of the launch and early orbit activities performed by the NASA Goddard Space Flight Center's (GSFC) Flight Dynamics Facility (FDF) in support of five probes comprising the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft. The FDF was tasked to support THEMIS in a limited capacity providing backup orbit determination support for validation purposes for all five THEMIS probes during launch plus 30 days in coordination with University of California Berkeley Flight Dynamics Center (UCB/FDC). The FDF's orbit determination responsibilities were originally planned to be as a backup to the UCB/FDC for validation purposes only. However, various challenges early on in the mission and a Spacecraft Emergency declared thirty hours after launch placed the FDF team in the role of providing the orbit solutions that enabled contact with each of the probes and the eventual termination of the Spacecraft Emergency. This paper details the challenges and various techniques used by the GSFC FDF team to successfully perform orbit determination for all five THEMIS probes during the early mission. In addition, actual THEMIS orbit determination results are presented spanning the launch and early orbit mission phase. Lastly, this paper enumerates lessons learned from the THEMIS mission, as well as demonstrates the broad range of resources and capabilities within the FDF for supporting critical launch and early orbit navigation activities, especially challenging for constellation missions.

Mission Success and Environmental Protection: Orbital Debris Considerations

NASA Technical Reports Server (NTRS)

Johnson, Nicholas

2007-01-01

The current U.S. National Space Policy specifically calls on U.S. Government entities "to follow the United States Government Orbital Debris Mitigation Standard Practices, consistent with mission requirements and cost effectiveness, in the procurement and operation of spacecraft, launch services, and the operation of tests and experiments in space. Early assessment (pre-PDR) of orbital debris mitigation compliance is essential to minimize development impacts. Orbital debris mitigation practices today are the most effective means to protect the near-Earth space environment for future missions.

Uncertainty Requirement Analysis for the Orbit, Attitude, and Burn Performance of the 1st Lunar Orbit Insertion Maneuver

NASA Astrophysics Data System (ADS)

Song, Young-Joo; Bae, Jonghee; Kim, Young-Rok; Kim, Bang-Yeop

2016-12-01

In this study, the uncertainty requirements for orbit, attitude, and burn performance were estimated and analyzed for the execution of the 1st lunar orbit insertion (LOI) maneuver of the Korea Pathfinder Lunar Orbiter (KPLO) mission. During the early design phase of the system, associate analysis is an essential design factor as the 1st LOI maneuver is the largest burn that utilizes the onboard propulsion system; the success of the lunar capture is directly affected by the performance achieved. For the analysis, the spacecraft is assumed to have already approached the periselene with a hyperbolic arrival trajectory around the moon. In addition, diverse arrival conditions and mission constraints were considered, such as varying periselene approach velocity, altitude, and orbital period of the capture orbit after execution of the 1st LOI maneuver. The current analysis assumed an impulsive LOI maneuver, and two-body equations of motion were adapted to simplify the problem for a preliminary analysis. Monte Carlo simulations were performed for the statistical analysis to analyze diverse uncertainties that might arise at the moment when the maneuver is executed. As a result, three major requirements were analyzed and estimated for the early design phase. First, the minimum requirements were estimated for the burn performance to be captured around the moon. Second, the requirements for orbit, attitude, and maneuver burn performances were simultaneously estimated and analyzed to maintain the 1st elliptical orbit achieved around the moon within the specified orbital period. Finally, the dispersion requirements on the B-plane aiming at target points to meet the target insertion goal were analyzed and can be utilized as reference target guidelines for a mid-course correction (MCC) maneuver during the transfer. More detailed system requirements for the KPLO mission, particularly for the spacecraft bus itself and for the flight dynamics subsystem at the ground control center

Ar-40 to Ar-39 ages of the large impact structures Kara and Manicouagan and their relevance to the Cretaceous-Tertiary and the Triassic-Jurassic boundary

NASA Technical Reports Server (NTRS)

Trieloff, M.; Jessberger, E. K.

1992-01-01

Since the discovery of the Ir enrichment in Cretaceous-Tertiary boundary clays in 1980, the effects of a 10-km asteroid impacting on the Earth 65 Ma ago have been discussed as the possible reason for the mass extinction--including the extinction of the dinosaurs--at the end of the Cretaceous. But up to now no crater of this age that is large enough (ca. 200 km in diameter) has been found. One candidate is the Kara Crater in northern Siberia. Kolesnikov et al. determined a K-Ar isochron of 65.6 +/- 0.5 Ma, indistinguishable from the age of the K-T boundary and interpreted this as confirmation of earlier proposals that the Kara bolide would have been at least one of the K-T impactors. Koeberl et al. determined Ar-40 to Ar-39 ages ranging from 70 to 82 Ma and suggested an association to the Campanian-Maastrichtian boundary, another important extinction horizon 73 Ma ago. We dated four impact melts, KA2-306, KA2-305, SA1-302, and AN9-182. Results from the investigation are discussed.

Geochemistry of the alginite and amorphous organic matter from type II-S kerogens

USGS Publications Warehouse

Stankiewicz, B.A.; Kruge, M.A.; Mastalerz, Maria; Salmon, G.L.

1996-01-01

Maceral fractions of the Type II-S kerogens from the Monterey Formation (Miocene. California. U.S.A.) and Duwi Formation (Campanian/Maastrichtian, Egypt) were separated by density gradient centrifugation. The Monterey Fm. kerogen sample was comprised chiefly of light red-fluorescing amorphous organic matter (AOM), the flash pyrolyzate of which was characterized by a predominance of alkylbenzenes, alkylthiophenes and alkylpyrroles. In contrast, the pyrolyzates of its alginite concentrate showed a highly aliphatic character, typical of this maceral, with the series of n-alkenes and n-alkanes (C6- C26) predominating. The pyrolyzate of the dominant light brown-fluorescing AOM of the Duwi Fm. kerogen had a relatively high concentration of alkylbenzenes and alkylthiophenes, while its elginite concentrate showed a more aliphatic character upon pyrolysis. There was a marked enrichment of thiophenic sulfur in the light-colored AOM of both samples (and also pyrrolic nitrogen in the case of the Monterey) relative to the alginite. The results support a bacterially-mediated, degradative origin for Type II-S amorphous organic matter, with algal remains as the primary source of the kerogen.

A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous of Western North America

PubMed Central

Lamanna, Matthew C.; Sues, Hans-Dieter; Schachner, Emma R.; Lyson, Tyler R.

2014-01-01

The oviraptorosaurian theropod dinosaur clade Caenagnathidae has long been enigmatic due to the incomplete nature of nearly all described fossils. Here we describe Anzu wyliei gen. et sp. nov., a new taxon of large-bodied caenagnathid based primarily on three well-preserved partial skeletons. The specimens were recovered from the uppermost Cretaceous (upper Maastrichtian) Hell Creek Formation of North and South Dakota, and are therefore among the stratigraphically youngest known oviraptorosaurian remains. Collectively, the fossils include elements from most regions of the skeleton, providing a wealth of information on the osteology and evolutionary relationships of Caenagnathidae. Phylogenetic analysis reaffirms caenagnathid monophyly, and indicates that Anzu is most closely related to Caenagnathus collinsi, a taxon that is definitively known only from a mandible from the Campanian Dinosaur Park Formation of Alberta. The problematic oviraptorosaurs Microvenator and Gigantoraptor are recovered as basal caenagnathids, as has previously been suggested. Anzu and other caenagnathids may have favored well-watered floodplain settings over channel margins, and were probably ecological generalists that fed upon vegetation, small animals, and perhaps eggs. PMID:24647078

Ar-40 to Ar-39 ages of the large impact structures Kara and Manicouagan and their relevance to the Cretaceous-Tertiary and the Triassic-Jurassic boundary

NASA Astrophysics Data System (ADS)

Trieloff, M.; Jessberger, E. K.

Since the discovery of the Ir enrichment in Cretaceous-Tertiary boundary clays in 1980, the effects of a 10-km asteroid impacting on the Earth 65 Ma ago have been discussed as the possible reason for the mass extinction--including the extinction of the dinosaurs--at the end of the Cretaceous. But up to now no crater of this age that is large enough (ca. 200 km in diameter) has been found. One candidate is the Kara Crater in northern Siberia. Kolesnikov et al. determined a K-Ar isochron of 65.6 +/- 0.5 Ma, indistinguishable from the age of the K-T boundary and interpreted this as confirmation of earlier proposals that the Kara bolide would have been at least one of the K-T impactors. Koeberl et al. determined Ar-40 to Ar-39 ages ranging from 70 to 82 Ma and suggested an association to the Campanian-Maastrichtian boundary, another important extinction horizon 73 Ma ago. We dated four impact melts, KA2-306, KA2-305, SA1-302, and AN9-182. Results from the investigation are discussed.

Orbital decomposition of CALIFA spiral galaxies

NASA Astrophysics Data System (ADS)

Zhu, Ling; van den Bosch, Remco; van de Ven, Glenn; Lyubenova, Mariya; Falcón-Barroso, Jesús; Meidt, Sharon E.; Martig, Marie; Shen, Juntai; Li, Zhao-Yu; Yildirim, Akin; Walcher, C. Jakob; Sanchez, Sebastian F.

2018-01-01

Schwarzschild orbit-based dynamical models are widely used to uncover the internal dynamics of early-type galaxies and globular clusters. Here we present for the first time the Schwarzschild models of late-type galaxies: an SBb galaxy NGC 4210 and an S0 galaxy NGC 6278 from the Calar Alto Legacy Integral Field Area (CALIFA) survey. The mass profiles within 2Re are constrained well with 1σ statistical error of ∼ 10 per cent. The luminous and dark mass can be disentangled with uncertainties of ∼20 and ∼ 50 per cent, respectively. From Re to 2Re, the dark matter fraction increases from 14 ± 10 to 18 ± 10 per cent for NGC 4210 and from 15 ± 10 to 30 ± 20 per cent for NGC 6278. The velocity anisotropy profiles of both σr/σt and σz/σR are well constrained. The inferred internal orbital distributions reveal clear substructures. The orbits are naturally separated into three components: a cold component with near circular orbits; a hot component with near radial orbits and a warm component in between. The photometrically identified exponential discs are predominantly made up of cold orbits only beyond ∼1Re, while they are constructed mainly with the warm orbits inside. Our dynamical hot components are concentrated in the inner regions, similar to the photometrically identified bulges. The reliability of the results, especially the orbit distribution, is verified by applying the model to mock data.

Evidence for a Past High-Eccentricity Lunar Orbit

NASA Technical Reports Server (NTRS)

Garrick-Betthell, Ian; Wisdom, Jack; Zuber, Maria T.

2007-01-01

The large differences between the Moon's three principal moments of inertia have been mystery since Laplace considered them in 1799. Here we present calculations that show how past high eccentricity orbits can account for the moment differences, represented by the low-order lunar gravity field and libration parameters. One of our solutions is that the Moon may have once been in a 3:2 resonance of the orbit period to spin-period, similar to Mercury's present state. The possibility of past high-eccentricity orbits suggests a rich dynamical history and may influence our understanding of the early thermal evolution of the Moon.

Stable isotope distribution in continental Maastrichtian vertebrates from the Haţeg Basin, South Carpathians

NASA Astrophysics Data System (ADS)

Bojar, Ana-Voica; Csiki, Zoltan; Grigorescu, Dan

2010-05-01

The oxygen isotopic compositions of biogenic apatite from crocodiles, turtles and dinosaurs, and their relationship to climate and physiology have been evidenced by several studies (Barrick and Showers, 1995; Kolodny et al., 1996; Barrick et al., 1999; Fricke and Rogers, 2000; Stoskopf et al., 2001; Straight et al., 2004; Amiot et al., 2007). To date, few attempts have been made to correlate the enamel d13C to dietary resources of dinosaurs (Bocherens et al., 1988; Stanton Thomas and Carlson, 2004; Fricke and Pearson, 2008; Fricke, et al., 2008). One additional complication is that for dinosaurs, the d18O of enamel phosphate depends on both body water and variations in body temperature. Several studies addressed the issue of endothermy vs. ectothermy of fossil vertebrates by studying inter- and intra-bone and enamel isotopic variability (Barrick and Showers, 1994, 1995; Barrick et al., 1996; 1998; Fricke and Rogers, 2000). More recent investigations provided evidence for inter-tooth temporal variations and related them to seasonality and/or changes in physiology (Straight et al., 2004; Stanton Thomas and Carlson, 2004). The main objectives of this study are to extract palaeoclimatic information considering, beside lithofacial characteristics and the isotopic distribution of carbonates formed in paleosols, the stable isotope composition of vertebrate remains from the Haţeg Basin. We also sampled several teeth along their growth axis in order to get further information about growth rates and the amplitude of isotopic variation. Located in the South Carpathians in Romania, the Haţeg Basin contains a thick sequence of Maastrichtian continental deposits yielding a rich dinosaur and mammalian fauna. Stable isotope analyses of both calcretes and dinosaur, crocodilian and turtle remains from two localities (Tuştea and Sibişel) were integrated in order to reconstruct environmental conditions during the Maastrichtian time and to gain further insights into the metabolism

The orbital distribution of Near-Earth Objects inside Earth's orbit

NASA Astrophysics Data System (ADS)

Greenstreet, Sarah; Ngo, Henry; Gladman, Brett

2012-01-01

Canada's Near-Earth Object Surveillance Satellite (NEOSSat), set to launch in early 2012, will search for and track Near-Earth Objects (NEOs), tuning its search to best detect objects with a < 1.0 AU. In order to construct an optimal pointing strategy for NEOSSat, we needed more detailed information in the a < 1.0 AU region than the best current model (Bottke, W.F., Morbidelli, A., Jedicke, R., Petit, J.M., Levison, H.F., Michel, P., Metcalfe, T.S. [2002]. Icarus 156, 399-433) provides. We present here the NEOSSat-1.0 NEO orbital distribution model with larger statistics that permit finer resolution and less uncertainty, especially in the a < 1.0 AU region. We find that Amors = 30.1 ± 0.8%, Apollos = 63.3 ± 0.4%, Atens = 5.0 ± 0.3%, Atiras (0.718 < Q < 0.983 AU) = 1.38 ± 0.04%, and Vatiras (0.307 < Q < 0.718 AU) = 0.22 ± 0.03% of the steady-state NEO population. Vatiras are a previously undiscussed NEO population clearly defined in our integrations, whose orbits lie completely interior to that of Venus. Our integrations also uncovered the unexpected production of retrograde orbits from main-belt asteroid sources; this retrograde NEA population makes up ≃0.1% of the steady-state NEO population. The relative NEO impact rate onto Mercury, Venus, and Earth, as well as the normalized distribution of impact speeds, was calculated from the NEOSSat-1.0 orbital model under the assumption of a steady-state. The new model predicts a slightly higher Mercury impact flux.

High-precision 14C and 40Ar/39Ar dating of the Campanian Ignimbrite (Y-5) reconciles the time-scales of climatic-cultural processes at 40 ka

NASA Astrophysics Data System (ADS)

Giacco, Biagio; Hajdas, Irka; Isaia, Roberto; Deino, Alan; Nomade, Sebastien

2017-04-01

The Campanian Ignimbrite (CI) super-eruption ( 40 ka, Southern Italy) is the largest known volcanic event of Mediterranean area. The CI tephra is widely dispersed through western Eurasia and occurs in close stratigraphic association with significant Late Pleistocene paleoclimatic and Paleolithic cultural events. This makes the CI tephra one of the most important tool for investigating several scientific issues ranging from volcanology, paleoclimatology to archaeology. Yet despite concerted attempts, the absolute age of the CI eruption is not well constrained. Here we present the first direct radiocarbon age for the CI obtained using accepted modern practices, from multiple 14C analyses of an exceptional large charred tree branch embedded in the lithified Yellow Tuff facies of the CI pyroclastic flow deposits, as well as new high-precision 40Ar/39Ar dating for the CI. These data substantially improve upon previous age determinations and permit fuller exploitation of the chronological potential of the CI tephra marker. Specifically, the results of our study are twofold: they provide (i) a robust pair of 14C and 40Ar/39Ar ages for refining both the radiocarbon calibration curve and the Late Pleistocene time-scale in the narrow, but significant time-span across CI event and (ii) compelling chronological evidence for the significance of the combined influence of the CI eruption and Heinrich Event 4 on European climate and potentially evolutionary processes of the Early Upper Palaeolithic.

The role of the 5f valence orbitals of early actinides in chemical bonding

PubMed Central

Vitova, T.; Pidchenko, I.; Fellhauer, D.; Bagus, P. S.; Joly, Y.; Pruessmann, T.; Bahl, S.; Gonzalez-Robles, E.; Rothe, J.; Altmaier, M.; Denecke, M. A.; Geckeis, H.

2017-01-01

One of the long standing debates in actinide chemistry is the level of localization and participation of the actinide 5f valence orbitals in covalent bonds across the actinide series. Here we illuminate the role of the 5f valence orbitals of uranium, neptunium and plutonium in chemical bonding using advanced spectroscopies: actinide M4,5 HR-XANES and 3d4f RIXS. Results reveal that the 5f orbitals are active in the chemical bonding for uranium and neptunium, shown by significant variations in the level of their localization evidenced in the spectra. In contrast, the 5f orbitals of plutonium appear localized and surprisingly insensitive to different bonding environments. We envisage that this report of using relative energy differences between the 5fδ/ϕ and 5fπ*/5fσ* orbitals as a qualitative measure of overlap-driven actinyl bond covalency will spark activity, and extend to numerous applications of RIXS and HR-XANES to gain new insights into the electronic structures of the actinide elements. PMID:28681848

The role of the 5f valence orbitals of early actinides in chemical bonding

NASA Astrophysics Data System (ADS)

Vitova, T.; Pidchenko, I.; Fellhauer, D.; Bagus, P. S.; Joly, Y.; Pruessmann, T.; Bahl, S.; Gonzalez-Robles, E.; Rothe, J.; Altmaier, M.; Denecke, M. A.; Geckeis, H.

2017-07-01

One of the long standing debates in actinide chemistry is the level of localization and participation of the actinide 5f valence orbitals in covalent bonds across the actinide series. Here we illuminate the role of the 5f valence orbitals of uranium, neptunium and plutonium in chemical bonding using advanced spectroscopies: actinide M4,5 HR-XANES and 3d4f RIXS. Results reveal that the 5f orbitals are active in the chemical bonding for uranium and neptunium, shown by significant variations in the level of their localization evidenced in the spectra. In contrast, the 5f orbitals of plutonium appear localized and surprisingly insensitive to different bonding environments. We envisage that this report of using relative energy differences between the 5fδ/φ and 5fπ*/5fσ* orbitals as a qualitative measure of overlap-driven actinyl bond covalency will spark activity, and extend to numerous applications of RIXS and HR-XANES to gain new insights into the electronic structures of the actinide elements.

[Orbital alveolar rhabdomyosarcoma masked by ethmoid sinusitis in a 25-year-old].

PubMed

Sanz-Marco, E; España, E; Alamar, A; Pérez-Rojas, J; López-Prats, M J; Díaz-Llopis, M

2014-05-01

A 25-year-old woman with right subacute sinusitis, complained about discomfort in her right eye. Clinical manifestations and computed tomography were suggestive of sub-periosteal orbital ethmoid wall abscess, for which the patient underwent urgent drainage. A solid tumor was found, with a positive biopsy for alveolar rhabdomyosarcoma. Complete remission and resolution of orbital symptoms were achieved with chemotherapy and radiation therapy. Alveolar orbital rhabdomyosarcoma in adults is uncommon. Rhabdomyosarcoma has a high risk of spreading. It can simulate a sinusitis, as in our patient, early diagnosis and early treatment being especially important in these patients. Copyright © 2010 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

Orbital penetration associated with tooth extraction.

PubMed

Smith, Mark M; Smith, Eric M; La Croix, Noelle; Mould, John

2003-03-01

Three cats and 2 dogs were evaluated for ophthalmologic complications associated with tooth extraction procedures. Orbital penetration leading to ocular and, in one case, brain trauma was secondary to iatrogenic injury from a dental elevator. Outcomes included enucleation of the affected eye in 3 cases, and death from brain abscessation in 1 case. Early treatment or, preferably, referral to a veterinary ophthalmology specialist may prevent such outcomes. Awareness of the anatomical proximity of caudal maxillary tooth roots and the orbit, appropriate interpretation of diagnostic intraoral dental radiographs, and technical proficiency in tooth extraction techniques will minimize these complications in veterinary dental practice.

STS mission duration enhancement study: (orbiter habitability)

NASA Technical Reports Server (NTRS)

Carlson, A. D.

1979-01-01

Habitability improvements for early flights that could be implemented with minimum impact were investigated. These included: (1) launching the water dispenser in the on-orbit position instead of in a locker; (2) the sleep pallet concept; and (3) suction cup foot restraints. Past studies that used volumetric terms and requirements for crew size versus mission duration were reviewed and common definitions of key habitability terms were established. An accurately dimensioned drawing of the orbiter mid-deck, locating all of the known major elements was developed. Finally, it was established that orbiter duration and crew size can be increased with minimum modification and impact to the crew module. Preliminary concepts of the aft med-deck, external versions of expanded tunnel adapters (ETA), and interior concepts of ETA-3 were developed and comparison charts showing the various factors of volume, weight, duration, size, impact to orbiter, and number of sleep stations were generated.

2016 Summer Series - Bethany Ehlmann - Early Mars: A View from Rovers and Orbiters

NASA Image and Video Library

2016-08-18

Water signatures include geological changes and life. Surface and orbital interplanetary robotic missions are critical for obtaining knowledge on atmospheric, surface and subsurface conditions of planets in our solar system. Ehlmann will talk about Mars data collected from orbital and rover missions and their implication for our understating of Mars past and present water environments.

Noise Control in Space Shuttle Orbiter

NASA Technical Reports Server (NTRS)

Goodman, Jerry R.

2009-01-01

Acoustic limits in habitable space enclosures are required to ensure crew safety, comfort, and habitability. Noise control is implemented to ensure compliance with the acoustic requirements. The purpose of this paper is to describe problems with establishing acoustic requirements and noise control efforts, and present examples of noise control treatments and design applications used in the Space Shuttle Orbiter. Included is the need to implement the design discipline of acoustics early in the design process, and noise control throughout a program to ensure that limits are met. The use of dedicated personnel to provide expertise and oversight of acoustic requirements and noise control implementation has shown to be of value in the Space Shuttle Orbiter program. It is concluded that to achieve acceptable and safe noise levels in the crew habitable space, early resolution of acoustic requirements and implementation of effective noise control efforts are needed. Management support of established acoustic requirements and noise control efforts is essential.

Combined orbits and clocks from IGS second reprocessing

NASA Astrophysics Data System (ADS)

Griffiths, Jake

2018-05-01

The Analysis Centers (ACs) of the International GNSS Service (IGS) have reprocessed a large global network of GPS tracking data from 1994.0 until 2014.0 or later. Each AC product time series was extended uniformly till early 2015 using their weekly operational IGS contributions so that the complete combined product set covers GPS weeks 730 through 1831. Three ACs also included GLONASS data from as early as 2002 but that was insufficient to permit combined GLONASS products. The reprocessed terrestrial frame combination procedures and results have been reported already, and those were incorporated into the ITRF2014 multi-technique global frame released in 2016. This paper describes the orbit and clock submissions and their multi-AC combinations and assessments. These were released to users in early 2017 in time for the adoption of IGS14 for generating the operational IGS products. While the reprocessing goal was to enable homogeneous modeling, consistent with the current operational procedures, to be applied retrospectively to the full history of observation data in order to achieve a more suitable reference for geophysical studies, that objective has only been partially achieved. Ongoing AC analysis changes and a lack of full participation limit the consistency and precision of the finished IG2 products. Quantitative internal measures indicate that the reprocessed orbits are somewhat less precise than current operational orbits or even the later orbits from the first IGS reprocessing campaign. That is even more apparent for the clocks where a lack of robust AC participation means that it was only possible to form combined 5-min clocks but not the 30-s satellite clocks published operationally. Therefore, retrospective precise point positioning solutions by users are not recommended using the orbits and clocks. Nevertheless, the orbits do support long-term stable user solutions when used with network processing with either double differencing or explicit clock

Magmatic complexity on early Mars as seen through a combination of orbital, in-situ and meteorite data

NASA Astrophysics Data System (ADS)

Sautter, Violaine; Toplis, Michael J.; Beck, Pierre; Mangold, Nicolas; Wiens, Roger; Pinet, Patrick; Cousin, Agnes; Maurice, Sylvestre; LeDeit, Laetitia; Hewins, Roger; Gasnault, Olivier; Quantin, Cathy; Forni, Olivier; Newsom, Horton; Meslin, Pierre-Yves; Wray, James; Bridges, Nathan; Payré, Valérie; Rapin, William; Le Mouélic, Stéphane

2016-06-01

Until recently, Mars was considered a basalt-covered world, but this vision is evolving thanks to new orbital, in situ and meteorite observations, in particular of rocks of the ancient Noachian period. In this contribution we summarise newly recognised compositional and mineralogical differences between older and more recent rocks, and explore the geodynamic implications of these new findings. For example the MSL rover has discovered abundant felsic rocks close to the landing site coming from the wall of Gale crater ranging from alkali basalt to trachyte. In addition, the recently discovered Martian regolith breccia NWA 7034 (and paired samples) contain many coarse-grained noritic-monzonitic clasts demonstrably Noachian in age, and even some clasts that plot in the mugearite field. Olivine is also conspicuously lacking in these ancient samples, in contrast to later Hesperian rocks. The alkali-suite requires low-degree melting of the Martian mantle at low pressure, whereas the later Hesperian magmatism would appear to be produced by higher mantle temperatures. Various scenarios are proposed to explain these observations, including different styles of magmatic activity (i.e. passive upwelling vs. hotspots). A second petrological suite of increasing interest involves quartzo-feldspathic materials that were first inferred from orbit, in local patches in the southern highlands and in the lower units of Valles Marineris. However, identification of felsic rocks from orbit is limited by the low detectability of feldspar in the near infrared. On the other hand, the MSL rover has described the texture, mineralogy and composition of felsic rocks in Gale crater that are granodiorite-like samples akin to terrestrial TTG (Tonalite-Trondhjemite-Granodiorite suites). These observations, and the low average density of the highlands crust, suggest the early formation of 'continental' crust on Mars, although the details of the geodynamic scenario and the importance of volatiles in

Speckle and spectroscopic orbits of the early A-type triple system Eta Virginis

NASA Technical Reports Server (NTRS)

Hartkopf, William I.; Mcalister, Harold A.; Yang, Xinxing; Fekel, Francis C.

1992-01-01

Eta Virginis is a bright (V = 3.89) triple system of composite spectral type A2 IV that has been observed for over a dozen years with both spectroscopy and speckle interferometry. Analysis of the speckle observations results in a long period of 13.1 yr. This period is also detected in residuals from the spectroscopic observations of the 71.7919 day short-period orbit. Elements of the long-period orbit were determined separately using the observations of both techniques. The more accurate elements from the speckle solution have been assumed in a simultaneous spectroscopic determination of the short- and long-period orbital elements. The magnitude difference of the speckle components suggests that lines of the third star should be visible in the spectrum.

Application of {sup 87}Sr/{sup 86}Sr, {delta}{sup 18}O and {delta}{sup 13}C Isotopes to diagenesis, correlation and connectivity of a fractured chalk reservoir, the Sidi El Kilani Field Tunisia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mearns, E.W.; Mcbride, J.J.; Bramwell, M.

1995-08-01

Strontium Stratigraphy Analysis of the primary matrix chalk of the Abiod Formation reservoir in the Sidi El Kilani Field indicate a Campanian to Maastrichtian age (Upper Cretaceous). A resolution of {+-}1Ma has been achieved and results suggest that there are no major stratigraphic breaks in the studied sequences. Sr-O-C isotope data from early fracture-filling calcite cements suggest they may have formed by the redistribution of CaCO{sub 3} from underlying carbonate sequences and may have precipitated at temperatures in the region of 35-55{degrees}C. The {sup 87}Sr/{sup 86}Sr isotope ratios of formation waters determined by residual salt analysis (SrRSA) suggest that themore » chemical evolution of waters during reservoir filling was controlled by the influx of basinal waters as opposed to in situ water-rock interaction. Late, fracture-filling dolomite and barite cements have Sr-O-C isotope characteristics consistent with precipitation from these migrating basinal fluids at temperatures similar to current reservoir conditions (70-75{degrees}C). Sr RSA results suggest that the reservoir section in two of the wells may have been in direct lateral communication at the time of oil emplacement. These wells however are separated by a strike-slip fault. The SrRSA results therefore suggest that the fault is a partial barrier which has restricted pressure equilibration in the relatively short timescale of oil production, but which may have allowed homogenization of Sr isotope ratios in formation water.« less

Depositional environment and distribution of Late Cretaceous [open quotes]source rocks[close quotes] from Costa Rica to West Africa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erlich, R.N.; Sofer, Z.; Pratt, L.M.

1993-02-01

Late Cretaceous [open quotes]source rocks[close quotes] from Costa Rica, western and eastern Venezuela, and Trinidad were studied using organic and inorganic geochemistry, biostratigraphy, and sedimentology in order to determine their depositional environments. Bulk mineralogy and major element geochemistry for 304 samples were combined with Rock Eval data and extract biomaker analysis to infer the types and distributions of the various Late Cretaceous productivity systems represented in the dataset. When data from this study are combined with published and proprietary data from offshore West Africa, Guyana/Suriname, and the central Caribbean, they show that these Late Cretaceous units can be correlated bymore » their biogeochemical characteristics to establish their temporal and spatial relationships. Paleogeographic maps constructed for the early to late Cenomanian, Turonian, Coniacian to middle Santonian, and late Santonian to latest Campanian show that upwelling and excessive fluvial runoff were probably the dominant sources of nutrient supply to the coastal productivity systems. The late Santonian to Maastrichtian rocks examined in this study indicate that organic material was poorly preserved after deposition, even though biologic productivity remained constant or changed only slightly. A rapid influx of oxygenated bottom water may have occurred following the opening of a deep water connection between the North and South Atlantic oceans, and/or separation of India from Africa and the establishment of an Antarctic oceanic connection. This study suggests that the most important factors that controlled source rock quality in northern South America were productivity, preservation, degree of clastic dilution, and subsurface diagenesis.« less

First In-Orbit Experience of TerraSAR-X Flight Dynamics Operations

NASA Technical Reports Server (NTRS)

Kahle, R.; Kazeminejad, B.; Kirschner, M.; Yoon, Y.; Kiehling, R.; D'Amico, S.

2007-01-01

TerraSAR-X is an advanced synthetic aperture radar satellite system for scientific and commercial applications that is realized in a public-private partnership between the German Aerospace Center (DLR) and the Astrium GmbH. TerraSAR-X was launched at June 15, 2007 on top of a Russian DNEPR-1 rocket into a 514 km sun-synchronous dusk-dawn orbit with an 11-day repeat cycle and will be operated for a period of at least 5 years during which it will provide high resolution SAR-data in the X-band. Due to the objectives of the interferometric campaigns the satellite has to comply to tight orbit control requirements, which are formulated in the form of a 250 m toroidal tube around a pre-flight determined reference trajectory (see [1] for details). The acquisition of the reference orbit was one of the main and key activities during the Launch and Early Orbit Phase (LEOP) and had to compensate for both injection errors and spacecraft safe mode attitude control thruster activities. The paper summarizes the activities of GSOC flight dynamics team during both LEOP and early Commissioning Phase, where the main tasks have been 1) the first-acquisition support via angle-tracking and GPS-based orbit determination, 2) maneuver planning for target orbit acquisition and maintenance, and 3) precise orbit and attitude determination for SAR processing support. Furthermore, a presentation on the achieved results and encountered problems will be addressed.

Orbital Debris: Past, Present, and Future

NASA Technical Reports Server (NTRS)

Stansbery, Gene; Johnson, Nicholas

2013-01-01

In the early days of spaceflight, the gBig Sky h theory was the near universally accepted paradigm for dealing with collisions of orbiting objects. This theory was also used during the early years of the aviation industry. Just as it did in aviation, the gBig Sky h theory breaks down as more and more objects accumulate in the environment. Fortunately, by the late 1970 fs some visionaries in NASA and the US Department of Defense (DoD) realized that trends in the orbital environment would inevitably lead to increased risks to operational spacecraft from collisions with other orbiting objects. The NASA Orbital Debris Program was established at and has been conducted at Johnson Space Center since 1979. At the start of 1979, fewer than 5000 objects were being tracked by the US Space Surveillance Network and very few attempts had been made to sample the environment for smaller sizes. Today, the number of tracked objects has quadrupled. Ground ]based and in situ measurements have statistically sampled the LEO environment over most sizes and mitigation guidelines and requirements are common among most space faring nations. NASA has been a leader, not only in defining the debris environment, but in promoting awareness of the issues in the US and internationally, and in providing leadership in developing policies to address the issue. This paper will discuss in broad terms the evolution of the NASA debris program from its beginnings to its present broad range of debris related research. The paper will discuss in some detail current research topics and will attempt to predict future research trends.

An Early Middle Eocene Orbital Scale Benthic Isotope Record From IODP Site 1408, Newfoundland Rise

NASA Astrophysics Data System (ADS)

Wu, F.; Lawler, N.; Penman, D. E.; Zachos, J. C.; Kirtland Turner, S.; Norris, R. D.; Wilson, P. A.; Hull, P. M.

2014-12-01

The long-term Paleogene global cooling trend and eventual glaciation of Antarctica has been attributed to a reduction in greenhouse gas levels as well as changes in the configuration of high-latitude oceanic gateways. This major trend in climate and forcing is known to have initiated in the early middle Eocene, between 44-49 Mya, yet our understanding of the detailed evolution of climate and oceanic circulation and carbon chemistry of this critical interval has been limited for lack of high-resolution proxy climate records. Integrated Ocean Drilling Program (IODP) Expedition 342, designed in part to address this deficiency, successfully recovered highly expanded sequences of middle Eocene sediment from multiple sites in the western North Atlantic, with several sites characterized by high sedimentation rates (>2.8 cm/kyr) and pronounced lithologic cycles. Using samples from cores recovered at one of these sites, 1408, located on Southeast Newfoundland Ridge, we are reconstructing the first orbital-scale deep sea δ18O and δ13C records spanning a ~1.6 million year interval (~Chron 20r) of the middle Eocene. Based on analyses of benthic foraminifer N. truempyi, our preliminary data reveal distinct high-frequency cycles with periods matching those of the orbital cycles, particularly precession and obliquity. Cross spectral analysis of δ18O, δ13C and lithologic records reveal a high degree of coherency, implying a high sensitivity in local sediment fluxes and bottom water chemistry (and circulation) to orbital forcing. Also, given the location and depth (~2600 m at 50 Ma), Site 1408 constrains the end-member composition of northern component bathyal bottom waters so that comparison with benthic isotope records from the south Atlantic and other basins can be used to assess ocean circulation patterns in the mid-Eocene. In general, bottom water temperatures appear to have been warmer, and DIC δ13C lower than observed elsewhere. Thus, our preliminary results are

Space Tourism: Orbital Debris Considerations

NASA Astrophysics Data System (ADS)

Mahmoudian, N.; Shajiee, S.; Moghani, T.; Bahrami, M.

2002-01-01

Space activities after a phase of research and development, political competition and national prestige have entered an era of real commercialization. Remote sensing, earth observation, and communication are among the areas in which this growing industry is facing competition and declining government money. A project like International Space Station, which draws from public money, has not only opened a window of real multinational cooperation, but also changed space travel from a mere fantasy into a real world activity. Besides research activities for sending man to moon and Mars and other outer planets, space travel has attracted a considerable attention in recent years in the form of space tourism. Four countries from space fairing nations are actively involved in the development of space tourism. Even, nations which are either in early stages of space technology development or just beginning their space activities, have high ambitions in this area. This is worth noting considering their limited resources. At present, trips to space are available, but limited and expensive. To move beyond this point to generally available trips to orbit and week long stays in LEO, in orbital hotels, some of the required basic transportations, living requirements, and technological developments required for long stay in orbit are already underway. For tourism to develop to a real everyday business, not only the price has to come down to meaningful levels, but also safety considerations should be fully developed to attract travelers' trust. A serious hazard to space activities in general and space tourism in particular is space debris in earth orbit. Orbiting debris are man-made objects left over by space operations, hazardous to space missions. Since the higher density of debris population occurs in low earth orbit, which is also the same orbit of interest to space tourism, a careful attention should be paid to the effect of debris on tourism activities. In this study, after a

Mars Observer/Transfer Orbit Stage (TOS)

NASA Technical Reports Server (NTRS)

1992-01-01

In the Payload Hazardous Servicing Facility, the integrated Mars Observer/Transfer Orbit Stage (TOS) payload is ready for encapsulation in the Titan III nose fairing. The TOS booster maiden flight was dedicated to Thomas O. Paine, a former NASA administrator who strongly supported interplanetary exploration and was an early backer of the TOS program. Launched September 25, 1992 from the Kennedy Space Flight Center aboard a Titan III rocket and the TOS, the Mars Observer spacecraft was to be the first U.S. spacecraft to study Mars since the Viking missions 18 years prior. Unfortunately, the Mars Observer spacecraft fell silent just 3 days prior to entering orbit around Mars.

Orbital manifestations in patients with acquired immunodeficiency syndrome.

PubMed

Sodhi, Punita Kumari

2014-01-01

The orbital manifestations of acquired immunodeficiency syndrome(AIDS) are uncommon. To provide a review of orbital manifestations of AIDS, the predisposing factors, investigations, treatment and outcome. Meticulous and systematic literature search of Pubmed to identify manuscripts describing orbital manifestations of AIDS was done and the articles were reviewed.The keywords used in the search were “orbit and AIDS”, “HIV positive and orbit”,“orbit manifestations in AIDS”, “orbital disease and AIDS” and “orbital infections and AIDS”. The orbital involvement in AIDS may present with opportunistic infections from organisms like fungi, viruses, bacteria and protozoa or with malignancies like Kaposi’s sarcoma, squamous cell carcinoma, smooth muscle cell tumors and lymphoma.The predisposing factors for orbital involvement in AIDS are low CD4+ cell count and the immunosuppressive states like diabetes, diabetic ketoacidosis, intravenous drug abuse and neutropenia. A patient may present with fever, headache, nausea, vomiting,decreased vision, ocular pain, and, in cases of mass formation, there is periorbital swelling, axial proptosis, globe displacement and swollen optic disc. Radiologically,mass formation, orbital bony destruction, and spread of disease to contiguous structures including the central nervous system may be seen. The medical management includes therapy for infection and HIV-1 protease inhibitors (highly active antiretroviral therapy)to suppress HIV-1 replication. For tumors, radical surgery including debulking followed by postoperative radiotherapy is generally needed. Orbital involvements with AIDS in any form, infective or malignancy, causes significant morbidity and mortality and should be diagnosed and managed as early as possible.

Orbit of the Patroclus-Menoetius Binary, a Lucy Mission Target

NASA Astrophysics Data System (ADS)

Noll, Keith

2016-10-01

We are proposing to observe Trojan binary asteroid (617) Patroclus-Menoetius, one of the targets of the Lucy mission. Lucy was selected as the next Discovery mission on January 4, 2017, for launch in October 2021. Observations this year are needed to establish the mutual orbit of the binary, which is of critical importance for mission planning. The mutual orbit phase is essentially undetermined from the accumulation of orbit period uncertainty since last measured in 2010. Orbital phase is needed in order to be able to predict the timing of mutual events that will begin late in 2017. These mutual events are essential to planning for the Lucy mission, especially in establishing the precise orientation of the mutual orbit plane and ascending node that is critical to early planning for flyby encounter design and capabilities.

Usachev in orbiter airlock

NASA Image and Video Library

2001-03-09

STS102-E-5019 (9 March 2001) --- Cosmonaut Yury V. Usachev, representing Rosaviakosmos, checks out two extravehicular mobility unit (EMU) space suits in the airlock of the Space Shuttle Discovery only hours away from assuming his role as a full fledged International Space Station crew member. Usachev, Expedition Two commander, and two astronauts are scheduled to trade places with two cosmonauts and an astronaut who have been onboard the orbiting outpost since early November 2000.

The Cretaceous-Tertiary boundary biotic crisis in the Basque country

NASA Technical Reports Server (NTRS)

Lamolda, M. A.

1988-01-01

The Zumaya section has been selected as a classic locality for the study of the Cretaceous-Tertiary (K-T) boundary due to its richness in microfaune, macrofaune, and nannoflora. The sections present similar good conditions for the study of the K-T boundary. The sedimentary rocks of the Uppermost Maastrichtian from the Basque Country are purple or pink marls and marls-tones. Above it is found a clayed bed, 40 to 29 cm thick, grey or dark grey in its basal part, of Lowermost Danian age. Above there is alternation of micritic grey-pink limestones and thin clay beds of Dano-Montian age. The average sedimentation is 7 to 8 times higher during the Upper Maastrichtian than in the Dano-Montian. The macrofauna underwent a decrease since the Campanian and was not found in the last 11 m of the Zumaya section; it was associated with changes in paleoceanographic conditions and primary productivity of the oceans. The microfossil assemblages in the K-T transition allows the recognition of several phases of a complex crisis between two well established planktonic ecosystems. In the Mayaroensis Zone there is a stable ecosystem with 45 to 47 planktonic foraminifera species. The disappearance of A. mayaroensis starts a degradation of the ecosystem. The number of planktonic foraminiera species decreases between 20 and 45 percent. The next phase of the crisis was the result of main extinction events in the planktonic calcareous ecosystem. There are several cretaceous planktonic foraminifera species, probably reworked, whose numbers decrease upward. The next and last phase of the biotic crisis shows a diversification of the ecosystem; the number of planktonic foraminifera is 2 to 3 times higher than before and it is noted the first appearance of Tertiary nannoflora species, while Cretaceous species decrease and persisting species are still the main ones.

Changing Depositional Conditions of the Cretaceous-Paleocene Sediments in the Southern Sakarya Zone and Implications for Tectonic Evolution

NASA Astrophysics Data System (ADS)

Baykut, Tanyel; Koral, Hayrettin; Özkar Öngen, İzver

2016-04-01

Study area is located between Göynük (Bolu) and Nallıhan (Ankara), NW Anatolia, to the north of the Neotethyan (Izmir-Ankara-Erzincan) Suture Zone. It comprises units ranging from the Jurassic to Miocene ages. Middle Jurassic-Lower Cretaceous age pelagic limestones of the Soǧukçam Formation is the oldest rock, overlain by the Upper Cretaceous Gölpazarı Group. The Gölpazarı Group includes the Cenomanian-Campanian age turbiditic Yenipazar Formation and the Maastrichtian age Taraklı Formation. Over the Taraklı Formation lies conformably the Kızılçay Group, and it exhibits varying facies from north to south of the study area. In the north, there occurs the coral-bearing Lower Paleocene Selvipınar Formation. In the south, instead, there are clastics of the Kızılçay Group overthrust by the Soǧukçam Formation. Clastics and bituminous shales of the Kızılçay Group indicate a terrestrial setting of the study area during the Lower Paleocene-Eocene. The Soǧukçam and Yenipazar Formations represent deep marine conditions, while the Taraklı Formation a shallow one. This indicates the region underwent a rapid uplift due possibly to initial collision and overthrusting. In the post-Maastrichtian age units, the occurrence and lateral transitions of shallow marine and terrestrial sediments suggest a progress of uplift, but at different rates at different locations; at a relatively fast rate in the south and a slow rate in the north. The presence of tectonic features such as E-W oriented folds, overturned folds and faults are related to shortening during a collisional stage that affected the whole region.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians carefully maneuver the Mars Climate Orbiter toward its workstand in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter is lifted clear of the top of its container in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2) oversee the removal of the Mars Climate Orbiter from its container. The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians lower the Mars Climate Orbiter onto its workstand in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), the Mars Climate Orbiter (background) is moved toward the workstand being readied by technicians (foreground). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians check the connections on the workstand holding the Mars Climate Orbiter in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

Reconstructing the plinian and co-ignimbrite sources of large volcanic eruptions: A novel approach for the Campanian Ignimbrite

PubMed Central

Marti, Alejandro; Folch, Arnau; Costa, Antonio; Engwell, Samantha

2016-01-01

The 39 ka Campanian Ignimbrite (CI) super-eruption was the largest volcanic eruption of the past 200 ka in Europe. Tephra deposits indicate two distinct plume forming phases, Plinian and co-ignimbrite, characteristic of many caldera-forming eruptions. Previous numerical studies have characterized the eruption as a single-phase event, potentially leading to inaccurate assessment of eruption dynamics. To reconstruct the volume, intensity, and duration of the tephra dispersal, we applied a computational inversion method that explicitly accounts for the Plinian and co-ignimbrite phases and for gravitational spreading of the umbrella cloud. To verify the consistency of our results, we performed an additional single-phase inversion using an independent thickness dataset. Our better-fitting two-phase model suggests a higher mass eruption rate than previous studies, and estimates that 3/4 of the total fallout volume is co-ignimbrite in origin. Gravitational spreading of the umbrella cloud dominates tephra transport only within the first hundred kilometres due to strong stratospheric winds in our best-fit wind model. Finally, tephra fallout impacts would have interrupted the westward migration of modern hominid groups in Europe, possibly supporting the hypothesis of prolonged Neanderthal survival in South-Western Europe during the Middle to Upper Palaeolithic transition. PMID:26883449

Reconstructing the plinian and co-ignimbrite sources of large volcanic eruptions: A novel approach for the Campanian Ignimbrite.

PubMed

Marti, Alejandro; Folch, Arnau; Costa, Antonio; Engwell, Samantha

2016-02-17

The 39 ka Campanian Ignimbrite (CI) super-eruption was the largest volcanic eruption of the past 200 ka in Europe. Tephra deposits indicate two distinct plume forming phases, Plinian and co-ignimbrite, characteristic of many caldera-forming eruptions. Previous numerical studies have characterized the eruption as a single-phase event, potentially leading to inaccurate assessment of eruption dynamics. To reconstruct the volume, intensity, and duration of the tephra dispersal, we applied a computational inversion method that explicitly accounts for the Plinian and co-ignimbrite phases and for gravitational spreading of the umbrella cloud. To verify the consistency of our results, we performed an additional single-phase inversion using an independent thickness dataset. Our better-fitting two-phase model suggests a higher mass eruption rate than previous studies, and estimates that 3/4 of the total fallout volume is co-ignimbrite in origin. Gravitational spreading of the umbrella cloud dominates tephra transport only within the first hundred kilometres due to strong stratospheric winds in our best-fit wind model. Finally, tephra fallout impacts would have interrupted the westward migration of modern hominid groups in Europe, possibly supporting the hypothesis of prolonged Neanderthal survival in South-Western Europe during the Middle to Upper Palaeolithic transition.

Anaerobic orbital cellulitis: a clinical and experimental study.

PubMed Central

Jedrzynski, M S; Bullock, J D; McGuire, T W; Elder, B L; Bullock, J D

1991-01-01

In this article we have reviewed the clinical and bacteriologic aspects of anaerobic orbital cellulitis and have presented six patients to illustrate these points. Physicians who treat patients with orbital cellulitis should have a high index of suspicion for possible instances involving anaerobes, so that appropriate management can be started early. To investigate this problem further, we created an animal model of anaerobic orbital cellulitis. This model may be useful in future studies of the pathogenesis and treatment of this serious and often devastating disease. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 FIGURE 8 FIGURE 9 FIGURE 10 FIGURE 11 FIGURE 12 FIGURE 13 FIGURE 14 FIGURE 15 FIGURE 16 FIGURE 17 FIGURE 18 FIGURE 19 PMID:1808813

A Brief History of Meteoroid and Orbital Debris Shielding Technology for US Manned Spacecraft

NASA Technical Reports Server (NTRS)

Bjorkman, Michael D.; Hyde, James L.

2008-01-01

Meteoroid and orbital debris shielding has played an important role from the beginning of manned spaceflight. During the early 60 s, meteoroid protection drove requirements for new meteor and micrometeoroid impact science. Meteoroid protection also stimulated advances in the technology of hypervelocity impact launchers and impact damage assessment methodologies. The first phase of meteoroid shielding assessments closed in the early 70 s with the end of the Apollo program. The second phase of meteoroid protection technology began in the early 80 s when it was determined that there is a manmade Earth orbital debris belt that poses a significant risk to LEO manned spacecraft. The severity of the Earth orbital debris environment has dictated changes in Space Shuttle and ISS operations as well as driven advances in shielding technology and assessment methodologies. A timeline of shielding technology and assessment methodology advances is presented along with a summary of risk assessment results.

Orbital cellulitis demands early recognition, urgent admission and aggressive management.

PubMed Central

Tole, D M; Anderton, L C; Hayward, J M

1995-01-01

Orbital cellulitis is an emergency. Confusion still exists between the diagnosis of this serious condition and that of preseptal cellulitis. Delay in treatment may cause blindness and progression to life-threatening sequelae such as brain abscess, meningitis or cavernous sinus thrombosis. We report a case in which, despite late referral, emergency surgical intervention was sight saving. Images Fig. 1 Fig. 2 PMID:7582417

Orbital floor reconstruction using a tensor fascia lata sling after total maxillectomy.

PubMed

Jung, Bok Ki; Yun, In Sik; Lee, Won Jai; Lew, Dae Hyun; Choi, Eun Chang; Lee, Dong Won

2016-05-01

Reconstruction after total maxillectomy with extensive orbital floor defects poses a significant challenge for the reconstruction. The aim of this study is to present the outcomes of orbital floor reconstruction using tensor fascia lata slings after total maxillectomy and to compare these results to orbital floor reconstruction using alloplastic implants. This was a retrospective analysis of 19 consecutive patients who underwent tumor resection with orbital floor removal for malignancies. Reconstructions were performed using either tensor fascia lata slings (Group A) or alloplastic implants (Group B). The early and late postoperative outcomes such as wound infection, plate exposure, ectropion, diplopia, and enophthalmos, were analyzed and compared between the two groups. Patients in group A had significantly less wound complication than in group B (p < 0.05). In group A, there were no early or late wound complications after the operation. However, in group B, five patients had infection, the plate was exposed in eight of fourteen patients, and three patients had enophthalmos. Eight patients in group B underwent reoperation to correct their complications. Reconstruction of the orbital floor with a tensor fascia lata sling offers reliable support to the globe and prevents the ophthalmic complications associated with loss of orbital support. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Orbital resonances of Taiwan's FORMOSAT-2 remote sensing satellite

NASA Astrophysics Data System (ADS)

Lin, Shin-Fa; Hwang, Cheinway

2018-06-01

Unlike a typical remote sensing satellite that has a global coverage and non-integral orbital revolutions per day, Taiwan's FORMOSAT-2 (FS-2) satellite has a non-global coverage due to the mission requirements of one-day repeat cycle and daily visit around Taiwan. These orbital characteristics result in an integer number of revolutions a day and orbital resonances caused by certain components of the Earth's gravity field. Orbital flight data indicated amplified variations in the amplitudes of FS-2's Keplerian elements. We use twelve years of orbital observations and maneuver data to analyze the cause of the resonances and explain the differences between the simulated (at the pre-launch stage) and real orbits of FS-2. The differences are quantified using orbital perturbation theories that describe secular and long-period orbital evolutions caused by resonances. The resonance-induced orbital rising rate of FS-2 reaches +1.425 m/day, due to the combined (modeled) effect of resonances and atmospheric drags (the relative modeling errors < 10%). The concave shapes in the time-evolution of the longitude of descending node (LonDN) coincide with the positive rates of daily semi-major axis (SMA) change, also caused by resonances. The non-zonal geopotential coefficients causing the resonance effects contributed up to 45% of FS-2's inclination decline. Our retrospective analysis of FS-2's resonant orbit can provide lessons for a remote sensing mission similar to FS-2, especially in the early mission design and planning phase.

The Mars Climate Orbiter is prepared for launch

NASA Technical Reports Server (NTRS)

1998-01-01

Technicians in the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2) prepare a lifting device they will use to remove the Mars Climate Orbiter from its container (behind the workers). The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Boeing Delta II 7425 rocket.

Orbital Maneuvering Vehicle (OMV) remote servicing kit

NASA Technical Reports Server (NTRS)

Brown, Norman S.

1988-01-01

With the design and development of the Orbital Maneuvering Vehicle (OMV) progressing toward an early 1990 initial operating capability (IOC), a new era in remote space operations will evolve. The logical progression to OMV front end kits would make available in situ satellite servicing, repair, and consummables resupply to the satellite community. Several conceptual design study efforts are defining representative kits (propellant tanks, debris recovery, module servicers); additional focus must also be placed on an efficient combination module servicer and consummables resupply kit. A remote servicer kit of this type would be designed to perform many of the early maintenance/resupply tasks in both nominal and high inclination orbits. The kit would have the capability to exchange Orbital Replacement Units (ORUs), exchange propellant tanks, and/or connect fluid transfer umbilicals. Necessary transportation system functions/support could be provided by interfaces with the OMV, Shuttle (STS), or Expendable Launch Vehicle (ELV). Specific remote servicer kit designs, as well as ground and flight demonstrations of servicer technology are necessary to prepare for the potential overwhelming need. Ground test plans should adhere to the component/system/breadboard test philosophy to assure maximum capability of one-g testing. The flight demonstration(s) would most likely be a short duration, Shuttle-bay experiment to validate servicer components requiring a micro-g environment.

The Completeness of the Fossil Record of Mesozoic Birds: Implications for Early Avian Evolution

PubMed Central

Brocklehurst, Neil; Upchurch, Paul; Mannion, Philip D.; O'Connor, Jingmai

2012-01-01

Many palaeobiological analyses have concluded that modern birds (Neornithes) radiated no earlier than the Maastrichtian, whereas molecular clock studies have argued for a much earlier origination. Here, we assess the quality of the fossil record of Mesozoic avian species, using a recently proposed character completeness metric which calculates the percentage of phylogenetic characters that can be scored for each taxon. Estimates of fossil record quality are plotted against geological time and compared to estimates of species level diversity, sea level, and depositional environment. Geographical controls on the avian fossil record are investigated by comparing the completeness scores of species in different continental regions and latitudinal bins. Avian fossil record quality varies greatly with peaks during the Tithonian-early Berriasian, Aptian, and Coniacian–Santonian, and troughs during the Albian-Turonian and the Maastrichtian. The completeness metric correlates more strongly with a ‘sampling corrected’ residual diversity curve of avian species than with the raw taxic diversity curve, suggesting that the abundance and diversity of birds might influence the probability of high quality specimens being preserved. There is no correlation between avian completeness and sea level, the number of fluviolacustrine localities or a recently constructed character completeness metric of sauropodomorph dinosaurs. Comparisons between the completeness of Mesozoic birds and sauropodomorphs suggest that small delicate vertebrate skeletons are more easily destroyed by taphonomic processes, but more easily preserved whole. Lagerstätten deposits might therefore have a stronger impact on reconstructions of diversity of smaller organisms relative to more robust forms. The relatively poor quality of the avian fossil record in the Late Cretaceous combined with very patchy regional sampling means that it is possible neornithine lineages were present throughout this interval but

A Sauropod Tooth from the Santonian of Hungary and the European Late Cretaceous 'Sauropod Hiatus'.

PubMed

Ősi, Attila; Csiki-Sava, Zoltán; Prondvai, Edina

2017-06-12

The lack of sauropod body fossils from the 20 My-long mid-Cenomanian to the late Campanian interval of the Late Cretaceous in Europe is referred to as the 'sauropod hiatus', with only a few footprints reported from the Apulian microplate (i.e. the southern part of the European archipelago). Here we describe a single tooth from the Santonian continental beds of Iharkút, Hungary, that represents the first European body fossil evidence of a sauropod from this critical time interval. The mosaic of derived and plesiomorphic features documented by the tooth crown morphology points to a basal titanosauriform affinity suggesting the occurrence of a clade of sauropods in the Upper Cretaceous of Europe that is quite different from the previously known Campano-Maastrichtian titanosaurs. Along with the footprints coming from shallow marine sediments, this tooth further strengthens the view that the extreme rarity of sauropod remains from this period of Europe is the result of sampling bias related to the dominance of coastal over inland sediments, in the latter of which sauropod fossils usually occur. This is also in line with the hypothesis that sauropods preferred inland habitats to swampy environments.

Hadrosauroid Dinosaurs from the Late Cretaceous of the Sultanate of Oman.

PubMed

Buffetaut, Eric; Hartman, Axel-Frans; Al-Kindi, Mohammed; Schulp, Anne S

2015-01-01

Fragmentary post-cranial remains (femora, tibia, vertebrae) of ornithischian dinosaurs from the Late Cretaceous of the Sultanate of Oman are described and referred to hadrosauroids. The specimens come from the Al-Khod Conglomerate, of latest Campanian to Maastrichtian age, in the north-eastern part of the country. Although the fragmentary condition of the fossils precludes a precise identification, various characters, including the shape of the fourth trochanter of the femur and the morphology of its distal end, support an attribution to hadrosauroids. With the possible exception of a possible phalanx from Angola, this group of ornithopod dinosaurs, which apparently originated in Laurasia, was hitherto unreported from the Afro-Arabian plate. From a paleobiogeographical point of view, the presence of hadrosauroids in Oman in all likelihood is a result of trans-Tethys dispersal from Asia or Europe, probably by way of islands in the Tethys shown on all recent paleogeographical maps of that area. Whether hadrosauroids were widespread on the Afro-Arabian landmass in the latest Cretaceous, or where restricted to the « Oman island » shown on some paleogeographical maps, remains to be determined.

Hadrosauroid Dinosaurs from the Late Cretaceous of the Sultanate of Oman

PubMed Central

Buffetaut, Eric; Hartman, Axel-Frans; Al-Kindi, Mohammed; Schulp, Anne S.

2015-01-01

Fragmentary post-cranial remains (femora, tibia, vertebrae) of ornithischian dinosaurs from the Late Cretaceous of the Sultanate of Oman are described and referred to hadrosauroids. The specimens come from the Al-Khod Conglomerate, of latest Campanian to Maastrichtian age, in the north-eastern part of the country. Although the fragmentary condition of the fossils precludes a precise identification, various characters, including the shape of the fourth trochanter of the femur and the morphology of its distal end, support an attribution to hadrosauroids. With the possible exception of a possible phalanx from Angola, this group of ornithopod dinosaurs, which apparently originated in Laurasia, was hitherto unreported from the Afro-Arabian plate. From a paleobiogeographical point of view, the presence of hadrosauroids in Oman in all likelihood is a result of trans-Tethys dispersal from Asia or Europe, probably by way of islands in the Tethys shown on all recent paleogeographical maps of that area. Whether hadrosauroids were widespread on the Afro-Arabian landmass in the latest Cretaceous, or where restricted to the « Oman island » shown on some paleogeographical maps, remains to be determined. PMID:26562674

orbit-estimation: Fast orbital parameters estimator

NASA Astrophysics Data System (ADS)

Mackereth, J. Ted; Bovy, Jo

2018-04-01

orbit-estimation tests and evaluates the Stäckel approximation method for estimating orbit parameters in galactic potentials. It relies on the approximation of the Galactic potential as a Stäckel potential, in a prolate confocal coordinate system, under which the vertical and horizontal motions decouple. By solving the Hamilton Jacobi equations at the turning points of the horizontal and vertical motions, it is possible to determine the spatial boundary of the orbit, and hence calculate the desired orbit parameters.

Lunar Reconnaissance Orbiter Orbit Determination Accuracy Analysis

NASA Technical Reports Server (NTRS)

Slojkowski, Steven E.

2014-01-01

Results from operational OD produced by the NASA Goddard Flight Dynamics Facility for the LRO nominal and extended mission are presented. During the LRO nominal mission, when LRO flew in a low circular orbit, orbit determination requirements were met nearly 100% of the time. When the extended mission began, LRO returned to a more elliptical frozen orbit where gravity and other modeling errors caused numerous violations of mission accuracy requirements. Prediction accuracy is particularly challenged during periods when LRO is in full-Sun. A series of improvements to LRO orbit determination are presented, including implementation of new lunar gravity models, improved spacecraft solar radiation pressure modeling using a dynamic multi-plate area model, a shorter orbit determination arc length, and a constrained plane method for estimation. The analysis presented in this paper shows that updated lunar gravity models improved accuracy in the frozen orbit, and a multiplate dynamic area model improves prediction accuracy during full-Sun orbit periods. Implementation of a 36-hour tracking data arc and plane constraints during edge-on orbit geometry also provide benefits. A comparison of the operational solutions to precision orbit determination solutions shows agreement on a 100- to 250-meter level in definitive accuracy.

Orbital cellulitis: a rare complication after orbital blowout fracture.

PubMed

Ben Simon, Guy J; Bush, Steven; Selva, Dinesh; McNab, Alan A

2005-11-01

To report the incidence of orbital cellulitis after orbital blowout fracture. Retrospective, noncomparative, interventional case series. All patients with orbital cellulitis and a history of recent orbital fracture. A medical record review of clinical history, imaging studies, and surgical and treatment outcome was performed. Resolution of orbital cellulitis and surgical and imaging findings. Four patients (3 male; mean age, 30 years [range, 4.5-58]) were treated for orbital cellulitis complicating orbital fracture. All patients had evidence of paranasal sinusitis before or after the orbital injury, and 2 also reported forceful nose blowing after sustaining orbital trauma. Although 3 patients received prophylactic oral antibiotics after the fracture, this failed to prevent infection. Sinusitis commenced 1 to 2 weeks before and as late as 5 weeks after orbital injury. All patients were treated with IV antibiotics. Two developed an orbital abscess that required surgical drainage; 1 patient improved after an endonasal maxillary antrostomy. One patient improved on IV antibiotics alone and underwent fracture repair at a later stage. These 4 patients represent 0.8% of all cases of orbital fractures treated in the study period. Orbital cellulitis is a rare complication of orbital fracture, and seems to be more common when paranasal sinus infection preexists or occurs within several weeks of the injury. Oral antibiotics given after the orbital injury may not prevent orbital cellulitis or abscess formation. Surgery may be required to drain orbital abscess or in nonresolving cellulitis to drain the paranasal sinuses. Fracture repair, if indicated, should be delayed, particularly if an alloplastic implant is used.

Single-stage soft tissue reconstruction and orbital fracture repair for complex facial injuries.

PubMed

Wu, Peng Sen; Matoo, Reshvin; Sun, Hong; Song, Li Yuan; Kikkawa, Don O; Lu, Wei

2017-02-01

Orbital fractures with open periorbital wounds cause significant morbidity. Timing of debridement with fracture repair and soft tissue reconstruction is controversial. This study focuses on the efficacy of early single-stage repair in combined bony and soft tissue injuries. Retrospective review. Twenty-three patients with combined open soft tissue wounds and orbital fractures were studied for single-stage orbital reconstruction and periorbital soft tissue repair. Inclusion criteria were open soft tissue wounds with clinical and radiographic evidence of orbital fractures and repair performed within 48 h after injury. Surgical complications and reconstructive outcomes were assessed over 6 months. The main outcome measures were enophthalmos, pre- and post-CT imaging of orbits, scar evaluation, presence of diplopia, and eyelid position. Enophthalmos was corrected in 16/19 cases and improved in 3/19 cases. 3D reconstruction of CT images showed markedly improved orbital alignment with objective measurements of the optic foramen to cornea distance (mm) in reconstructed orbits relative to intact orbits of 0.66, 95% confidence interval [CI] (lower 0.33, upper 0.99) mm. The mean baseline of Stony Brook Scar Evaluation Scale was 0.6, 95%CI (0.30-0.92), and for 6 months, the mean score was 3.4, 95%CI (3.05-3.73). Residual diplopia in secondary gazes was present in two patients; one patient had ectropion. Complications included one case of local wound infection. An early single-stage repair of combined soft tissue and orbital fractures yields satisfactory functional and aesthetic outcomes. Complications are low and likely related to trauma severity. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Analysis of orbital perturbations acting on objects in orbits near geosynchronous earth orbit

NASA Technical Reports Server (NTRS)

Friesen, Larry J.; Jackson, Albert A., IV; Zook, Herbert A.; Kessler, Donald J.

1992-01-01

The paper presents a numerical investigation of orbital evolution for objects started in GEO or in orbits near GEO in order to study potential orbital debris problems in this region. Perturbations simulated include nonspherical terms in the earth's geopotential field, lunar and solar gravity, and solar radiation pressure. Objects simulated include large satellites, for which solar radiation pressure is insignificant, and small particles, for which solar radiation pressure is an important force. Results for large satellites are largely in agreement with previous GEO studies that used classical perturbation techniques. The orbit plane of GEO satellites placed in a stable plane orbit inclined approximately 7.3 deg to the equator experience very little precession, remaining always within 1.2 percent of their initial orientation. Solar radiation pressure generates two major effects on small particles: an orbital eccentricity oscillation anticipated from previous research, and an oscillation in orbital inclination.

Orbital debris removal and meteoroid deflection

NASA Astrophysics Data System (ADS)

Campbell, Jonathan W.; Taylor, Charles R.; Smalley, Larry L.; Dickerson, Thomas

1998-11-01

Orbital debris in low-Earth orbit in the size range from 1 to 10 cm in diameter can be detected but not tracked reliably enough to be avoided by spacecraft. It can cause catastrophic damage even to a shielded spacecraft. With adaptive optics, a ground-based pulsed laser ablating the debris surface can produce enough propulsion in several hundred pulses to cause such debris to reenter the atmosphere. A single laser station could remove all of the 1 - 10 cm debris in three years or less. A technology demonstration of laser space propulsion is proposed which would pave the way for the implementation of such a debris removal system. The cost of the proposed demonstration is comparable with the estimated annual cost of spacecraft operations in the present orbital debris environment. Orbital debris is not the only space junk that is deleterious to the Earth's environment. Collisions with asteroids have caused major havoc to the Earth's biosphere many times in the ancient past. Since the possibility still exists for major impacts of asteroids with the Earth, it shown that it is possible to scale up the systems to prevent these catastrophic collisions providing sufficient early warning is available from new generation space telescopes plus deep space radar tracking.

TOPEX/POSEIDON orbit maintenance maneuver design

NASA Technical Reports Server (NTRS)

Bhat, R. S.; Frauenholz, R. B.; Cannell, Patrick E.

1990-01-01

The Ocean Topography Experiment (TOPEX/POSEIDON) mission orbit requirements are outlined, as well as its control and maneuver spacing requirements including longitude and time targeting. A ground-track prediction model dealing with geopotential, luni-solar gravity, and atmospheric-drag perturbations is considered. Targeting with all modeled perturbations is discussed, and such ground-track prediction errors as initial semimajor axis, orbit-determination, maneuver-execution, and atmospheric-density modeling errors are assessed. A longitude targeting strategy for two extreme situations is investigated employing all modeled perturbations and prediction errors. It is concluded that atmospheric-drag modeling errors are the prevailing ground-track prediction error source early in the mission during high solar flux, and that low solar-flux levels expected late in the experiment stipulate smaller maneuver magnitudes.

Design of the Recovery Trajectory for JAXA Venus Orbiter Akatsuki

NASA Astrophysics Data System (ADS)

Campagnola, Stefano; Kawakatsu, Yasuhiro

2015-12-01

Akatsuki ("dawn" in Japanese) is the JAXA Venus orbiter that was scheduled to enter orbit around Venus on Dec. 7 th , 2010. Following the failure of the main engine during the orbit insertion maneuver, the spacecraft escaped Venus on a 200-day orbit around the Sun, only to return in early 2017. This paper presents the design and implementation of the recovery trajectory, which involves perihelion maneuvers to re-encounter Venus in late 2015. Relying only on the onboard propellant, the trajectory rescued the mission by (1) anticipating the beginning of the science phase within the nominal lifetime of the spacecraft, and (2) halving the Δ v requirements for the orbit insertion maneuver. Several trajectories are designed with an innovative use of a technique called non-tangent V-Infinity Leveraging Transfers (VILTs). Candidate solutions are then recomputed in higher fidelity models, and one solution is finally selected for its low Δv requirements and for programmatic reasons. The results of the perihelion maneuver campaign are also presented.

Launch and Early Orbit Operations for CryoSat-2

NASA Astrophysics Data System (ADS)

Mardel, Nic; Marchese, Franco

2010-12-01

CryoSat-2 was launched from Baikonur on 8th of April 2010 aboard a modified Dnepr ICBM, the so-called SS18 Satan. Following the ascent and separation from the launch vehicle the Flight Operations Segment (FOS) in ESOC, Darmstadt started the operations to configure the satellite into the correct mode to acquire science; switching on units, configuring software and ensuring that the satellite health and performance was as expected. This paper will describe the operations performed by the FOS during the first weeks in orbit, including the unexpected problems encountered, their implications and solutions.

Solid Propulsion De-Orbiting and Re-Orbiting

NASA Astrophysics Data System (ADS)

Schonenborg, R. A. C.; Schoyer, H. F. R.

2009-03-01

With many "innovative" de-orbit systems (e.g. tethers, aero breaking, etc.) and with natural de-orbit, the place of impact of unburned spacecraft debris on Earth can not be determined accurately. The idea that satellites burn up completely upon re-entry is a common misunderstanding. To the best of our knowledge only rocket motors are capable of delivering an impulse that is high enough, to conduct a de-orbit procedure swiftly, hence to de-orbit at a specific moment that allows to predict the impact point of unburned spacecraft debris accurately in remote areas. In addition, swift de-orbiting will reduce the on-orbit time of the 'dead' satellite, which reduces the chance of the dead satellite being hit by other dead or active satellites, while spiralling down to Earth during a slow, 25 year, or more, natural de-orbit process. Furthermore the reduced on-orbit time reduces the chance that spacecraft batteries, propellant tanks or other components blow up and also reduces the time that the object requires tracking from Earth.The use of solid propellant for the de-orbiting of spacecraft is feasible. The main advantages of a solid propellant based system are the relatively high thrust and the facts that the system can be made autonomous quite easily and that the system can be very reliable. The latter is especially desirable when one wants to de-orbit old or 'dead' satellites that might not be able to rely anymore on their primary systems. The disadvantage however, is the addition of an extra system to the spacecraft as well as a (small) mass penalty. [1]This paper describes the above mentioned system and shows as well, why such a system can also be used to re-orbit spacecraft in GEO, at the end of their life to a graveyard orbit.Additionally the system is theoretically compared to an existing system, of which performance data is available.A swift market analysis is performed as well.

The Campanian Ignimbrite Eruption, Heinrich Event 4, and palaeolithic change in Europe: A high-resolution investigation

NASA Astrophysics Data System (ADS)

Fedele, Francesco G.; Giaccio, Biagio; Isaia, Roberto; Orsi, Giovanni

The Campanian Ignimbrite (CI) eruption from the Phlegraean Fields Caldera, southern Italy, represents one of the largest late Quaternary volcanic event. Its recent dating at 39,280±110 yr BP draws attention to the occurrence of this volcanic catastrophe during a time interval characterized by biocultural modifications in western Eurasia. These included the Middle to Upper Palaeolithic transition and the supposed change from Neandertal to "modern" Homo sapiens anatomy, a subject of continuing investigation and controversy. The paper aims to clarify the position and relevance of the CI event in this context. At several archaeological sites of southeastern Europe, the CI ash separates the cultural layers containing Middle Palaeolithic and/or "Earliest Upper Palaeolithic" assemblages from the layers in which Upper Palaeolithic industries occur. At the same sites the CI tephra coincides with a long interruption of occupation. The palaeclimatic records containing the CI products show that the eruption occurred just at the beginning of Heinrich Event 4 (HE4), which was characterized by extreme climatic conditions, compared to the other HEs. From the observation of this concurrence of factors, we advance the hypothesis of a positive climate-volcanism feedback triggered by the co-occurrence of the CI eruption and HE4 onset. Both the environmental and cultural data available for a c.5000-year interval on either side of the event, suggest that a reappraisal of the identity and destiny of the archaeological industries representing the so-called Middle to Upper Palaeolithictransition is in order. This might force a reassessment of the Upper Palaeolithic notion as traditionally employed.

Marine vs. local control on seawater Nd-isotope ratios at the northwest coast of Africa during the late Cretaceous-early Eocene

NASA Astrophysics Data System (ADS)

Kocsis, L.; Gheerbrant, E.; Mouflih, M.; Cappetta, H.; Ulianov, A.; Chiaradia, M.

2013-12-01

At the northwest corner of Africa excellent conditions existed for phosphate formation (i.e., stable upwelling system) during the late Cretaceous-early Eocene. This is probably in relation to stable tectonic evolution of shallow epicontinental basins at a passive continental margin and to their paleogeographic situation between the Atlantic and Tethys marine realms. To better comprehend paleoceanic conditions in this area, radiogenic isotope ratios (87Sr/86Sr and 143Nd/144Nd) and trace element compositions of fossil biogenic apatite are investigated from Maastrichtian to Ypresian shallow marine phosphorite deposits in Morocco (Ouled Abdoun and Ganntour Basins). Rare earth elements (REE) distributions in the fossils are compatible with early diagenetic marine pore fluid represented by negative Ce-anomaly and heavy REE enrichment. An overall shift in Ce-anomaly is apparent with gradually lower values in younger fossils along three distinct assemblages that correspond to Maastrichtian, Danian-Thanetian and Ypresian periods. The temporal change can be interpreted as presence of gradually more oxygenated seawater in the basins. Strontium isotopic ratios of the fossils follow the global Sr-evolution curve. However, the latest Cretaceous and the oldest Paleocene fossils yielded slightly higher ratios than the global ocean, which could reflect minor diagenetic alteration. Neodymium isotopic ratios are quite even along the phosphate series with ɛNd(t) values ranges from -6.8 to -5.8. These values are higher than those reported for average North Atlantic deep water and Tethyan seawater (e.g., Stille et al., 1996; Thomas et al., 2003). For the origin of the stable, high 143Nd/144Nd we propose three main hypotheses: (1) contribution of continental Nd-source, (2) locally controlled deep water Nd-isotope ratios near the coast from where upwelling originated in the area and (3) possible surface marine water contribution from the Pacific across the Atlantic. Stille, P., Steinmann

High resolution chronology of late Cretaceous-early Tertiary events determined from 21,000 yr orbital-climatic cycles in marine sediments

NASA Technical Reports Server (NTRS)

Herbert, Timothy D.; Dhondt, Steven

1988-01-01

A number of South Atlantic sites cored by the Deep Sea Drilling Project (DSDP) recovered late Cretaceous and early Tertiary sediments with alternating light-dark, high-low carbonate content. The sedimentary oscillations were turned into time series by digitizing color photographs of core segments at a resolution of about 5 points/cm. Spectral analysis of these records indicates prominent periodicity at 25 to 35 cm in the Cretaceous intervals, and about 15 cm in the early Tertiary sediments. The absolute period of the cycles that is determined from paleomagnetic calibration at two sites is 20,000 to 25,000 yr, and almost certainly corresponds to the period of the earth's precessional cycle. These sequences therefore contain an internal chronometer to measure events across the K/T extinction boundary at this scale of resolution. The orbital metronome was used to address several related questions: the position of the K/T boundary within magnetic chron 29R, the fluxes of biogenic and detrital material to the deep sea immediately before and after the K/T event, the duration of the Sr anomaly, and the level of background climatic variability in the latest Cretaceous time. The carbonate/color cycles that were analyzed contain primary records of ocean carbonate productivity and chemistry, as evidenced by bioturbational mixing of adjacent beds and the weak lithification of the rhythmic sequences. It was concluded that sedimentary sequences that contain orbital cyclicity are capable of providing resolution of dramatic events in earth history with much greater precision than obtainable through radiometric methods. The data show no evidence for a gradual climatic deterioration prior to the K/T extinction event, and argue for a geologically rapid revolution at this horizon.

The Mars Climate Orbiter arrives at KSC to begin final preparations for launch

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter spacecraft is moved into the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2) in KSC's industrial area. It arrived at the Shuttle Landing Facility aboard an Air Force C-17 cargo plane early this morning following its flight from the Lockheed Martin Astronautics plant in Denver, Colo. When it arrives at the red planet, the Mars Climate Orbiter will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Delta II 7425 rocket.

The Mars Climate Orbiter arrives at KSC to begin final preparations for launch

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter spacecraft is moved onto a flatbed for transport to the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). It arrived at KSC's Shuttle Landing Facility aboard an Air Force C-17 cargo plane early this morning following its flight from the Lockheed Martin Astronautics plant in Denver, Colo. When it arrives at the red planet, the Mars Climate Orbiter will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Delta II 7425 rocket.

Shuttle on-orbit rendezvous targeting: Circular orbits

NASA Technical Reports Server (NTRS)

Bentley, E. L.

1972-01-01

The strategy and logic used in a space shuttle on-orbit rendezvous targeting program are described. The program generates ascent targeting conditions for boost to insertion into an intermediate parking orbit, and generates on-orbit targeting and timeline bases for each maneuver to effect rendezvous with a space station. Time of launch is determined so as to eliminate any plane change, and all work was performed for a near-circular space station orbit.

Preliminary stratigraphy and facies analysis of the Upper Cretaceous Kaguyak Formation, including a brief summary of newly discovered oil stain, upper Alaska Peninsula

USGS Publications Warehouse

Wartes, Marwan A.; Decker, Paul L.; Stanley, Richard G.; Herriott, Trystan M.; Helmold, Kenneth P.; Gillis, Robert J.

2013-01-01

The Alaska Division of Geological and Geophysical Surveys has an ongoing program aimed at evaluating the Mesozoic forearc stratigraphy, structure, and petroleum systems of lower Cook Inlet. Most of our field studies have focused on the Jurassic component of the petroleum system (this report). However, in late July and early August of 2012, we initiated a study of the stratigraphy and reservoir potential of the Upper Cretaceous Kaguyak Formation. The Kaguyak Formation is locally well exposed on the upper Alaska Peninsula (fig. 25) and was named by Keller and Reiser (1959) for a sequence of interbedded siltstone and sandstone of upper Campanian to Maastrichtian age that they estimated to be 1,450 m thick.Subsequent work by Detterman and Miller (1985) examined 900 m of section and interpreted the unit as the record of a prograding submarine fan.This interpretation of deep-water deposition contrasts with other Upper Cretaceous rocks exposed along the Alaska Peninsula and lower Cook Inlet that are generally described as nonmarine to shallow marine (Detterman and others, 1996; LePain and others, 2012).Based on foraminifera and palynomorphs from the COST No. 1 well, Magoon (1986) concluded that the Upper Cretaceous rocks were deposited in a variety of water depths and environments ranging from upper bathyal to nonmarine. During our recent fieldwork west and south of Fourpeaked Mountain, we similarly encountered markedly varying lithofacies in the Kaguyak Formation (fig. 25), and we also found oil-stained rocks that are consistent with the existence of an active petroleum system in Upper Cretaceous rocks on the upper Alaska Peninsula and in lower Cook Inlet. These field observations are summarized below.

Benthic foraminiferal assemblages and microfacies analysis of the Upper Cretaceous-Paleocene (?) platform carbonate sequence in the Central Taurides, S Turkey

NASA Astrophysics Data System (ADS)

Solak, Cemile; Taslı, Kemal; Koç, Hayati

2017-04-01

The Upper Cretaceous succession outcropping in the area known as Anamas-Akseki Autochton or Geyikdaǧı Unit, which is situated western part of the Central Taurides, consists of approximately 500 m thick purely platform carbonate sediments. Integrated microfacies/facies studies and biostratigraphic analysis of the Kuyucak stratigraphic section provided to recognise depositional settings and benthic foraminiferal biozones. The Upper Cretaceous begins with Cenomanian limestones intercalated with limestone breccias (Unit 1) containing mainly Pseudorhapydionina dubia, Cuneolina pavonia, Nezzazata simplex (Association 1) and unconformably overlies the Lower Cretaceous (Barremian-Aptian) limestones with Vercorsella laurentii, Praechrysalidina infracretacea and Salpingoporella hasi. The Cenomanian limestones include benthic foraminiferal packstone/wackestone, peloidal packstone/wackestone and mudstone microfacies deposited restricted platform conditions. Intercalations of emersion breccias suggest sporadic subaerial exposure of the platform. The Cenomanian succession are truncated by an unconformity characterised by locale bauxite infills. Immediately above the unconformable surface, dolomitic limestones and rudistid limestones (Unit 2) are assigned to the upper Campanian based on the benthic foraminiferal assemblage (Association 2) comprising mainly Murciella cuvillieri, Pseudocyclammina sphaeroidea, Accordiella conica, Scandonea samnitica and Fleuryana adriatica. The upper Campanian limestones composed of dominantly benthic foraminiferal packstone/wackestone microfacies deposited in shallow water environments with low water energy, subjected to restriction in water circulation, The following limestones of the Unit 2 is characterised by sporadic intercalation of "open shelf" Orbitoides, Omphalocyclus, Siderolites assemblage (Association 3), assigned to the Maastrichtian, in addition to pre-existing "restricted platform" species. Pseudedomia hekimhanensis and

Cosmonaut Usachev on the orbiter middeck

NASA Image and Video Library

2001-03-09

STS102-E-5039 (9 March 2001) --- Cosmonaut Yury V. Usachev, representing Rosaviakosmos, handles a locker's content on the mid deck of the Space Shuttle Discovery only hours away from assuming his role as a full fledged International Space Station crew member. Usachev, Expedition Two commander, and two astronauts are scheduled to trade places with two cosmonauts and an astronaut who have been onboard the orbiting outpost since early November 2000.

Analyses of space environment effects on active fiber optic links orbited aboard the LDEF

NASA Technical Reports Server (NTRS)

Taylor, Edward W.; Monarski, T. W.; Berry, J. N.; Sanchez, A. D.; Padden, R. J.; Chapman, S. P.

1993-01-01

The results of the 'Preliminary Analysis of WL Experiment no. 701, Space Environment Effects on Operating Fiber Optic Systems,' is correlated with space simulated post retrieval terrestrial studies performed on the M0004 experiment. Temperature cycling measurements were performed on the active optical data links for the purpose of assessing link signal to noise ratio and bit error rate performance some 69 months following the experiment deployment in low Earth orbit. The early results indicate a high correlation between pre-orbit, orbit, and post-orbit functionality of the first known and longest space demonstration of operating fiber optic systems.

[Orbital inflammation].

PubMed

Mouriaux, F; Coffin-Pichonnet, S; Robert, P-Y; Abad, S; Martin-Silva, N

2014-12-01

Orbital inflammation is a generic term encompassing inflammatory pathologies affecting all structures within the orbit : anterior (involvement up to the posterior aspect of the globe), diffuse (involvement of intra- and/or extraconal fat), apical (involvement of the posterior orbit), myositis (involvement of only the extraocular muscles), dacryoadenitis (involvement of the lacrimal gland). We distinguish between specific inflammation and non-specific inflammation, commonly referred to as idiopathic inflammation. Specific orbital inflammation corresponds to a secondary localization of a "generalized" disease (systemic or auto-immune). Idiopathic orbital inflammation corresponds to uniquely orbital inflammation without generalized disease, and thus an unknown etiology. At the top of the differential diagnosis for specific or idiopathic orbital inflammation are malignant tumors, represented most commonly in the adult by lympho-proliferative syndromes and metastases. Treatment of specific orbital inflammation begins with treatment of the underlying disease. For idiopathic orbital inflammation, treatment (most often corticosteroids) is indicated above all in cases of visual loss due to optic neuropathy, in the presence of pain or oculomotor palsy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

The METOP-A Orbit Acquisition Strategy and its LEOP Operational Experience

NASA Technical Reports Server (NTRS)

Merz, K.; Serrano, M. A. Martin; Kuijper, D.; Matatoros, M. A. Garcia

2007-01-01

Europe's first polar-orbiting weather satellite, METOPA, was launched by a Soyuz launcher from Baikonur Cosmodrome on the 19th of October of 2006. The routine operations of METOP-A are conducted by EUMETSAT (European Organization for Exploitation of Meteorological Satellites) in the frame of the European Polar System mission (EPS). The METOP-A Launch and Early Orbit Phase (LEOP) operations have been performed by ESA/ESOC. The Flight Dynamics Orbit Determination and Control team (OD&C) at ESOC was in charge of correcting the S/C orbit as delivered by the launcher in such a way that EUMETSAT would be able to acquire the reference orbit with a drift-stop manoeuvre approximately two weeks after a LEOP of 3 days and Hand-Over to the EUMETSAT Control Centre (EUMETSAT-CC) in Darmstadt, Germany. The various strict constraints and the short amount of time available for ESOC operations made this task challenging. Several strategies were prepared before launch and analysed during LEOP based on the achieved injection orbit. This paper presents the different manoeuvre strategies investigated and finally applied to acquire the operational orbit, reporting as well the details of its execution and final achieved state.

Early Results from TUS, the First Orbital Detector of Extreme Energy Cosmic Rays

NASA Astrophysics Data System (ADS)

Zotov, Mikhail

TUS is the world's first orbital detector of extreme energy cosmic rays (EECRs), which operates as a part of the scientific payload of the Lomonosov satellite since May 19, 2016. TUS employs the nocturnal atmosphere of the Earth to register ultraviolet (UV) fluorescence and Cherenkov radiation from extensive air showers generated by EECRs as well as UV radiation from lightning strikes and transient luminous events, micro-meteors and space debris. The first months of its operation in orbit have demonstrated an unexpectedly rich variety of UV radiation in the atmosphere. We briefly review the design of TUS and present a few examples of events recorded in a mode dedicated to registering EECRs.

Orbital variability in the eclipsing pulsar binary PSR B1957+20

NASA Technical Reports Server (NTRS)

Arzoumanian, Z.; Fruchter, A. S.; Taylor, J. H.

1994-01-01

We have conducted timing observations of the eclipsing millisecond binary pulsar PSR B1957+20, extending the span of data on this pulsar to more than five years. During this time the orbital period of the system has varied by roughly Delta P(sub b)/P(sub b) = 1.6 x 10(exp -7), changing quardratically with time and displaying with time and displaying an orbital period second derivative of P(sub b) = (1.43 +/- 0.08) x 10(exp -18)/sec. The previous measurement of a large negative orbital period derivative reflected only the short-term behavior of the system during the early observations; the orbital period derivative is now positive. If, as we suspect, the PSR B1957+20 system is undergoing quasi-cyclic orbital period variations similar to those found in other close binaries such as Algol and RS CVn, then the 0.025 solar mass companion to PSR B1957+20 is most likely non-degenerate, convective, and magnetically active.

UV SURFACE ENVIRONMENT OF EARTH-LIKE PLANETS ORBITING FGKM STARS THROUGH GEOLOGICAL EVOLUTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rugheimer, S.; Sasselov, D.; Segura, A.

2015-06-10

The UV environment of a host star affects the photochemistry in the atmosphere, and ultimately the surface UV environment for terrestrial planets and therefore the conditions for the origin and evolution of life. We model the surface UV radiation environment for Earth-sized planets orbiting FGKM stars in the circumstellar Habitable Zone for Earth through its geological evolution. We explore four different types of atmospheres corresponding to an early-Earth atmosphere at 3.9 Gyr ago and three atmospheres covering the rise of oxygen to present-day levels at 2.0 Gyr ago, 0.8 Gyr ago, and modern Earth. In addition to calculating the UVmore » flux on the surface of the planet, we model the biologically effective irradiance, using DNA damage as a proxy for biological damage. We find that a pre-biotic Earth (3.9 Gyr ago) orbiting an F0V star receives 6 times the biologically effective radiation as around the early Sun and 3520 times the modern Earth–Sun levels. A pre-biotic Earth orbiting GJ 581 (M3.5 V) receives 300 times less biologically effective radiation, about 2 times modern Earth–Sun levels. The UV fluxes calculated here provide a grid of model UV environments during the evolution of an Earth-like planet orbiting a range of stars. These models can be used as inputs into photo-biological experiments and for pre-biotic chemistry and early life evolution experiments.« less

James Webb Space Telescope Orbit Determination Analysis

NASA Technical Reports Server (NTRS)

Yoon, Sungpil; Rosales, Jose; Richon, Karen

2014-01-01

The James Webb Space Telescope (JWST) is designed to study and answer fundamental astrophysical questions from an orbit about the Sun-Earth/Moon L2 libration point, 1.5 million km away from Earth. This paper describes the results of an orbit determination (OD) analysis of the JWST mission emphasizing the challenges specific to this mission in various mission phases. Three mid-course correction (MCC) maneuvers during launch and early orbit phase and transfer orbit phase are required for the spacecraft to reach L2. These three MCC maneuvers are MCC-1a at Launch+12 hours, MCC-1b at L+2.5 days and MCC-2 at L+30 days. Accurate OD solutions are needed to support MCC maneuver planning. A preliminary analysis shows that OD performance with the given assumptions is adequate to support MCC maneuver planning. During the nominal science operations phase, the mission requires better than 2 cm/sec velocity estimation performance to support stationkeeping maneuver planning. The major challenge to accurate JWST OD during the nominal science phase results from the unusually large solar radiation pressure force acting on the huge sunshield. Other challenges are stationkeeping maneuvers at 21-day intervals to keep JWST in orbit around L2, frequent attitude reorientations to align the JWST telescope with its targets and frequent maneuvers to unload momentum accumulated in the reaction wheels. Monte Carlo analysis shows that the proposed OD approach can produce solutions that meet the mission requirements.

Magnetospheric Multiscale (MMS) Mission Commissioning Phase Orbit Determination Error Analysis

NASA Technical Reports Server (NTRS)

Chung, Lauren R.; Novak, Stefan; Long, Anne; Gramling, Cheryl

2009-01-01

The Magnetospheric MultiScale (MMS) mission commissioning phase starts in a 185 km altitude x 12 Earth radii (RE) injection orbit and lasts until the Phase 1 mission orbits and orientation to the Earth-Sun li ne are achieved. During a limited time period in the early part of co mmissioning, five maneuvers are performed to raise the perigee radius to 1.2 R E, with a maneuver every other apogee. The current baseline is for the Goddard Space Flight Center Flight Dynamics Facility to p rovide MMS orbit determination support during the early commissioning phase using all available two-way range and Doppler tracking from bo th the Deep Space Network and Space Network. This paper summarizes th e results from a linear covariance analysis to determine the type and amount of tracking data required to accurately estimate the spacecraf t state, plan each perigee raising maneuver, and support thruster cal ibration during this phase. The primary focus of this study is the na vigation accuracy required to plan the first and the final perigee ra ising maneuvers. Absolute and relative position and velocity error hi stories are generated for all cases and summarized in terms of the ma ximum root-sum-square consider and measurement noise error contributi ons over the definitive and predictive arcs and at discrete times inc luding the maneuver planning and execution times. Details of the meth odology, orbital characteristics, maneuver timeline, error models, and error sensitivities are provided.

Preliminary Assessment of Suomi-NPP VIIRS On-orbit Radiometric Performance

NASA Technical Reports Server (NTRS)

Oudrari, Hassan; DeLuccia, Frank; McIntire, Jeff; Moyer, David; Chiang, Vincent; Xiong, Xiao-xiong; Butler, James

2012-01-01

The Visible-Infrared Imaging Radiometer Suite (VIIRS) is a key instrument on-board the Suomi National Polar-orbiting Partnership (NPP) spacecraft that was launched on October 28th 2011. VIIRS was designed to provide moderate and imaging resolution of most of the globe twice daily. It is a wide-swath (3,040 km) cross-track scanning radiometer with spatial resolutions of 370.and 740 m at nadir for imaging and moderate bands, respectively. It has 22 spectral bands covering the spectrum between 0.412 11m and 12.01 11m, including 14 reflective solar bands (RSB), 7 thermal emissive bands (TEB), and 1 day-night band (ON B). VIIRS observations are used to generate 22 environmental data products (EORs). This paper will briefly describe NPP VIIRS calibration strategies performed by the independent government team, for the initial on-orbit Intensive Calibration and Validation (ICV) activities. In addition, this paper will provide an early assessment of the sensor on-orbit radiometric performance, such as the sensor signal to noise ratios (SNRs), dual gain transition verification, dynamic range and linearity, reflective bands calibration based on the solar diffuser (SO) and solar diffuser stability monitor (SOSM), and emissive bands calibration based on the on-board blackbody calibration (OBC). A comprehensive set of performance metrics generated during the pre-launch testing program will be compared to VIIRS on-orbit early performance, and a plan for future cal/val activities and performance enhancements will be presented.

Spectral properties of minimal-basis-set orbitals: Implications for molecular electronic continuum states

NASA Astrophysics Data System (ADS)

Langhoff, P. W.; Winstead, C. L.

Early studies of the electronically excited states of molecules by John A. Pople and coworkers employing ab initio single-excitation configuration interaction (SECI) calculations helped to simulate related applications of these methods to the partial-channel photoionization cross sections of polyatomic molecules. The Gaussian representations of molecular orbitals adopted by Pople and coworkers can describe SECI continuum states when sufficiently large basis sets are employed. Minimal-basis virtual Fock orbitals stabilized in the continuous portions of such SECI spectra are generally associated with strong photoionization resonances. The spectral attributes of these resonance orbitals are illustrated here by revisiting previously reported experimental and theoretical studies of molecular formaldehyde (H2CO) in combination with recently calculated continuum orbital amplitudes.

Confirmation of Earth-Mass Planets Orbiting the Millisecond Pulsar PSR B1257 + 12.

PubMed

Wolszczan, A

1994-04-22

The discovery of two Earth-mass planets orbiting an old ( approximately 10(9) years), rapidly spinning neutron star, the 6.2-millisecond radio pulsar PSR B1257+12, was announced in early 1992. It was soon pointed out that the approximately 3:2 ratio of the planets' orbital periods should lead to accurately predictable and possibly measurable gravitational perturbations of their orbits. The unambiguous detection of this effect, after 3 years of systematic timing observations of PSR B1257+12 with the 305-meter Arecibo radiotelescope, as well as the discovery of another, moon-mass object in orbit around the pulsar, constitutes irrefutable evidence that the first planetary system around a star other than the sun has been identified.

Orbit Determination Toolbox

NASA Technical Reports Server (NTRS)

Carpenter, James R.; Berry, Kevin; Gregpru. Late; Speckman, Keith; Hur-Diaz, Sun; Surka, Derek; Gaylor, Dave

2010-01-01

The Orbit Determination Toolbox is an orbit determination (OD) analysis tool based on MATLAB and Java that provides a flexible way to do early mission analysis. The toolbox is primarily intended for advanced mission analysis such as might be performed in concept exploration, proposal, early design phase, or rapid design center environments. The emphasis is on flexibility, but it has enough fidelity to produce credible results. Insight into all flight dynamics source code is provided. MATLAB is the primary user interface and is used for piecing together measurement and dynamic models. The Java Astrodynamics Toolbox is used as an engine for things that might be slow or inefficient in MATLAB, such as high-fidelity trajectory propagation, lunar and planetary ephemeris look-ups, precession, nutation, polar motion calculations, ephemeris file parsing, and the like. The primary analysis functions are sequential filter/smoother and batch least-squares commands that incorporate Monte-Carlo data simulation, linear covariance analysis, measurement processing, and plotting capabilities at the generic level. These functions have a user interface that is based on that of the MATLAB ODE suite. To perform a specific analysis, users write MATLAB functions that implement truth and design system models. The user provides his or her models as inputs to the filter commands. The software provides a capability to publish and subscribe to a software bus that is compliant with the NASA Goddard Mission Services Evolution Center (GMSEC) standards, to exchange data with other flight dynamics tools to simplify the flight dynamics design cycle. Using the publish and subscribe approach allows for analysts in a rapid design center environment to seamlessly incorporate changes in spacecraft and mission design into navigation analysis and vice versa.

Morphology and kinematics of orbital components in CALIFA galaxies across the Hubble sequence

NASA Astrophysics Data System (ADS)

Zhu, Ling; van de Ven, Glenn; Méndez-Abreu, Jairo; Obreja, Aura

2018-06-01

Based on the stellar orbit distribution derived from orbit-superposition Schwarzschild models, we decompose each of 250 representative present-day galaxies into four orbital components: cold with strong rotation, warm with weak rotation, hot with dominant random motion and counter-rotating (CR). We rebuild the surface brightness (Σ) of each orbital component and we present in figures and tables a quantification of their morphologies using the Sersic index n, concentration C = log {(Σ _{0.1R_e}/Σ _{R_e})} and intrinsic flattening qRe and qRmax, with Re the half-light-radius and Rmax the CALIFA data coverage. We find that: (1) kinematic hotter components are generally more concentrated and rounder than colder components, and (2) all components become more concentrated and thicker/rounder in more massive galaxies; they change from disk-like in low mass late-type galaxies to bulge-like in high-mass early type galaxies. Our findings suggest that Sersic n is not a good discriminator between rotating bulges and non-rotating bulges. The luminosity fraction of cold orbits fcold is well correlated with the photometrically-decomposed disk fraction fdisk as f_{cold} = 0.14 + 0.23f_{disk}. Similarly, the hot orbit fraction fhot is correlated with the bulge fraction fbulge as f_{hot} = 0.19 + 0.31f_{bulge}. The warm orbits mainly contribute to disks in low-mass late-type galaxies, and to bulges in high-mass early-type galaxies. The cold, warm, and hot components generally follow the same morphology (ɛ = 1 - qRmax) versus kinematics (σ _z^2/\\overline{V_{tot}^2}) relation as the thin disk, thick disk/pseudo bulge, and classical bulge identified from cosmological simulations.

The Mars Climate Orbiter arrives at KSC to begin final preparations for launch

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter spacecraft arrives at KSC's Shuttle Landing Facility aboard an Air Force C-17 cargo plane early this morning following its flight from the Lockheed Martin Astronautics plant in Denver, Colo. When the spacecraft arrives at the red planet, it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Delta II 7425 rocket.

Reinterpretation of the palynology and age of Laramide syntectonic deposits, southwestern Montana, and revision of the Beaverhead Group

NASA Astrophysics Data System (ADS)

Nichols, D. J.; Perry, W. J., Jr.; Haley Johns, J. C.

1985-02-01

New palynological data from syntectonic deposits in southwestern Montana have major temporal implications for Laramide structural relations in the northern Rocky Mountains. Conglomerate and associated sandstones representing the bulk of material eroded from the thrust-faulted margin of the Blacktail-Snowcrest foreland massif are middle Campanian (Aquilapollenites senonicus Interval Zone; estimated absolute age 78 81 Ma). As a major consequence, the foreland buttress responsible for the shape of the southwestern Montana recess of the Cordilleran thrust belt was uplifted and in place by middle Campanian time. Palynomorph assemblages from the Campanian deposits include reworked spores of Paleozoic age that are evidence of provenance. Other less precisely dated syntectonic units in the area differ in age and provenance as well as lithology. Formerly, all these deposits were assigned to the Beaverhead Formation, which is raised to group status herein. The stratigraphic unit shed from the Blacktail-Snowcrest uplift is raised to formation status as the Lima Conglomerate. The term “Beaverhead Group” is restricted to the Lima Conglomerate and to contemporaneous and younger conglomeratic units that differ in lithology and probably in provenance; older sandstone units are removed from the Beaverhead Group. Deposits at the original type section of the Beaverhead Formation are not precisely dated but are no older than Campanian and probably no younger than early Maestrichtian.

Accuracy in Orbital Propagation: A Comparison of Predictive Software Models

DTIC Science & Technology

2017-06-01

astrology and astronomy , as ancient cultures observed patterns in the sun and moon [2]. These early observers and philosophers sought to devise...methods and observations of the time would shape the science and mathematics still in use in modern orbital mechanics [3]. Astronomy and astrology...B.C.), who gained early fame by predicting eclipses, and would go on to be one of the founders of Greek philosophy and astronomy [4]. He was the

Possible tidal resonance of the early Earth's ocean due to the lunar orbit evolution

NASA Astrophysics Data System (ADS)

Motoyama, M.; Tsunakawa, H.; Takahashi, F.

2016-12-01

The ocean tide is one of the most important factors affecting the Earth's surface environment and the evolution of the Earth-Moon system (e.g. Goldreich, 1966). According to the Giant Impact hypothesis, the Moon was formed very near the Earth 4.6 billion years ago (Hartmann and Davis, 1979). At that time, the tidal force would be about several thousand times as strong as the present. However previous studies pointed out that significant attenuation of tidal waves might have occurred due to mechanical response of water motion (e.g. Hansen, 1982; Abe and Ooe, 2001), resulting in relatively calm state like the present ocean.In the present study, we analyze tidal response of the ocean on the early Earth using a model of constant-depth ocean covering all the surface of the rigid Earth. The examined modes of response are not only M2 corresponding to spherical harmonics Y22 but also others such as Y21, since the lunar orbital plane would be inclined.First, estimated is an ocean depth for possible resonance of the individual mode. Eigen frequencies of the fluid on a rotating sphere with no friction are calculated on the basis of previous study (Longuet-Higgins, 1968). These frequencies depend on the Earth's rotation rate and the ocean depth. The Earth's rotation period is assumed to have changed from 5 hours to 24 hours for the past 4.6 billion years (e.g. Mignard, 1980; Stacey and Davis, 2008). It is found that resonance could occur for diurnal modes of Y21 and Y31 with reasonable depths of the ancient ocean (1300 - 5200 m).Then we obtain a 2D response function on a sphere with friction in order to estimate the tidal amplitude of the ocean for main modes . The response function in the present study shows good agreement with the numerical simulation result of the tidal torque response of M2 (Abe et al., 1997). The calculation results suggest that diurnal modes of Y21 and Y31 would grown on the early Earth, while the other modes would fairly be attenuated. In particular

[Orbital compartment syndrome. The most frequent cause of blindness following facial trauma].

PubMed

Klenk, Gusztáv; Katona, József; Kenderfi, Gábor; Lestyán, János; Gombos, Katalin; Hirschberg, Andor

2017-09-01

Although orbital compartment syndrome is a rare condition, it is still the most common cause of blindness following simple or complicated facial fractures. Its pathomechanism is similar to the compartment syndrome in the limb. Little extra fluid (blood, oedema, brain, foreign body) in a non-space yielding space results with increasingly higher pressures within a short period of time. Unless urgent surgical intervention is performed the blocked circulation of the central retinal artery will result irreversible ophthalmic nerve damage and blindness. Aim, material and method: A retrospective analysis of ten years, 2007-2017, in our hospital among those patients referred to us with facial-head trauma combined with blindness. 571 patients had fractures involving the orbit. 23 patients become blind from different reasons. The most common cause was orbital compartment syndrome in 17 patients; all had retrobulbar haematomas as well. 6 patients with retrobulbar haematoma did not develop compartment syndrome. Compartment syndrome was found among patient with extensive and minimal fractures such as with large and minimal haematomas. Early lateral canthotomy and decompression saved 7 patients from blindness. We can not predict and do not know why some patients develop orbital compartment syndrome. Compartment syndrome seems independent from fracture mechanism, comminution, dislocation, amount of orbital bleeding. All patients are in potential risk with midface fractures. We have a high suspicion that orbital compartment syndrome has been somehow missed out in the recommended textbooks of our medical universities and in the postgraduate trainings. Thus compartment syndrome is not recognized. Teaching, training and early surgical decompression is the only solution to save the blind eye. Orv Hetil. 2017; 158(36): 1410-1420.

[Vertical retraction syndrome caused by anomalous orbital structures].

PubMed

Yang, Qiong; Jiao, Yong-hong; Man, Feng-yuan; Wang, Zhen-chang; Chang, Qing-lin; Lu, Wei; Wang, Jing-hui; Zhao, Kan-xing

2011-11-01

To described the clinical feature and MRI imaging of six children with vertical retraction syndrome. Six children with unilateral vertical retraction syndrome between 15 months and 8 years of age, mean age was (5.01 ± 1.27) years old. Strabismus examination included diopter, prism diopters, eye movement examination, binocular vision and fundus examination. Imaging of the ocular motor nerves at the brainstem was performed in 0.8 mm thickness image planes using 3D-FIESTA sequence, the orbits were imaged with FSE T1, T2WI using surface coils, and within 2.0 mm thick planes. Four children showed hypertropia, characterized by limited depression, a light retraction of the globe during downward gaze and eyelid lag. The MRI imaging showed anomalous orbital structure in the superonasal quadrant that between medial rectus and superior rectus or adjacent to the superior rectus. Two children showed intermittent exotropia, characterized by limited elevation, retraction of the globe and narrowing of the palpebral fissure during upward gaze. The MRI imaging showed anomalous orbital structure was present in the inferotemporal quadrant, one originate in inferior rectus and another close to the lateral rectus. Anomalous orbital structures are a main cause of vertical retraction syndrome. The presence of specific unusual eye movement and MRI imaging may assist in diagnosis. When the eyelid lag was found since the early age, anomalous orbital structures were implied.

Analysis for orbital rendezvous of Chang'E-5 using SBI technique

NASA Astrophysics Data System (ADS)

Huang, Y.; Shan, Q.; Li, P.

2016-12-01

Chang'E-5 will be launched in later 2017/early 2018 using a new generation rocket from Wenchang satellite launch center, Hainan, China. It is a lunar sampling return mission, and it is the first time for China to carry out orbital rendezvous and docking in the Moon. How to achieve orbital rendezvous successfully in the Moon is very important in Chang'E-5 mission. Orbital rendezvous will be implemented between an orbiter and an ascender 200 km above the Moon. The ground tracking techniques include range, Doppler and VLBI, and they will be used to track the orbiter and the ascender when the ascender is about 70 km farther away from the orbiter. Later the ascender will approach the orbiter automatically. As a successful example, in Chang'E-3, the differential phase delay (delta delay) data between the rover and the lander are obtained with a random error of about 1 ps, and the relative position of the rover is determined with an accuracy of several meters by using same beam VLBI (SBI) technique. Here the application of the SBI technique for Chang'E-5 orbital rendezvous is discussed. SBI technique can be used to track the orbiter and the ascender simultaneously when they are in the same beam. Delta delay of the two probes can be derived, and the measurement accuracy is much higher than that of the traditional VLBI data because of the cancelation of common errors. Theoretically it can result in a more accurate relative orbit between the two probes. In the simulation, different strategies are discussed to analyze the contribution of SBI data to the orbit accuracy improvement especially relative orbit between the orbiter and ascender. The simulation results show that the relative position accuracy of the orbiter and ascender can reach about 1 m with delta delay data of 10 ps.

Mars Reconnaissance Orbiter: Aerobraking Science Analysis

NASA Astrophysics Data System (ADS)

Bougher, Stephen W.; Keating, G. M.

2006-09-01

The Mars Reconnaissance Orbiter (MRO) spacecraft was launched from the Kennedy Space Center in Florida on August 12, 2005, and arrived at Mars on March 10, 2006. Aerobraking in the martian thermosphere was conducted for nearly 5-months after arrival, enabling the desired MRO mapping orbit to be achieved. The MRO aerobraking phase began in early martian northern Spring (Ls = 36) and continued through early northern Summer (Ls 110), spanning approximately 500 orbits. The MRO periapsis latitude migrated slowly poleward/southward from 70ºS latitude upon aerobraking initiation, passed over the South pole (near Ls = 77), and moved rapidly northward to equatorial latitudes at aerobraking conclusion. Upper atmosphere sampling ( 100-200 km) was achieved on the dayside (LT 1900-2000) before polar crossing, and on the nightside (LT = 0200-0300) thereafter. These seasonal and latitude conditions are similar to a subset of those experienced by MGS during its post hiatus aerobraking Phase 2. Derived mass densities, scale heights, and estimated temperatures are the primary data products generated from each aeropass. The most important discovery of MRO aerobraking concerns the sampling of the thermosphere up to 200 km, far higher than previous MGS and Odyssey Accelerometers have achieved. This sampling contributes to the characterization of the Mars exobase region, which is required to predict and interpret atmospheric escape rates. In addition, thermospheric densities at a constant altitude were observed to decrease toward the southern (winter) pole, as expected from previous MGS experience. No winter polar warming was typically observed near the South pole. Thereafter, densities were measured to increase on the nightside as periapsis moved toward the equator. In general, thermospheric variability was observed to increase in the vicinity of the polar vortex boundary ( 70-80ºS), and decreased again inside the vortex (high southern latitudes). Finally, longitude wave features

Orbiter wheel and tire certification

NASA Technical Reports Server (NTRS)

Campbell, C. C., Jr.

1985-01-01

The orbiter wheel and tire development has required a unique series of certification tests to demonstrate the ability of the hardware to meet severe performance requirements. Early tests of the main landing gear wheel using conventional slow roll testing resulted in hardware failures. This resulted in a need to conduct high velocity tests with crosswind effects for assurance that the hardware was safe for a limited number of flights. Currently, this approach and the conventional slow roll and static tests are used to certify the wheel/tire assembly for operational use.

The orbit properties of colliding co-orbiting bodies

NASA Technical Reports Server (NTRS)

Freeman, John W.

1987-01-01

It is generally assumed that an ensemble of small bodies located in similar Keplarian orbits will, because of collisions, tend to disperse into more and more dissimilar orbits. This theory was challenged. Alfven maintains that for the case where the time between collisions is longer than the orbit period and the collisions are essentially inelastic the orbits and velocities will become more similar. This gives rise to the concepts of negative diffusion and jet streams. It is proposed that this question might be investigated experimentally using the space station. The proposed experiment is briefly described.

Orbits: Computer simulation

NASA Technical Reports Server (NTRS)

Muszynska, A.

1985-01-01

In rotating machinery dynamics an orbit (Lissajous curve) represents the dynamic path of the shaft centerline motion during shaft rotation and resulting precession. The orbit can be observed with an oscilloscope connected to XY promixity probes. The orbits can also be simulated by a computer. The software for HP computer simulates orbits for two cases: (1) Symmetric orbit with four frequency components with different radial amplitudes and relative phase angles; and (2) Nonsymmetric orbit with two frequency components with two different vertical/horizontal amplitudes and two different relative phase angles. Each orbit carries a Keyphasor mark (one-per-turn reference). The frequencies, amplitudes, and phase angles, as well as number of time steps for orbit computation, have to be chosen and introduced to the computer by the user. The orbit graphs can be observed on the computer screen.

Early On-Orbit Performance of the Visible Infrared Imaging Radiometer Suite Onboard the Suomi National Polar-Orbiting Partnership (S-NPP) Satellite

NASA Technical Reports Server (NTRS)

Cao, Changyong; DeLuccia, Frank J.; Xiong, Xiaoxiong; Wolfe, Robert; Weng, Fuzhong

2014-01-01

The Visible Infrared Imaging Radiometer Suite (VIIRS) is one of the key environmental remote-sensing instruments onboard the Suomi National Polar-Orbiting Partnership spacecraft, which was successfully launched on October 28, 2011 from the Vandenberg Air Force Base, California. Following a series of spacecraft and sensor activation operations, the VIIRS nadir door was opened on November 21, 2011. The first VIIRS image acquired signifies a new generation of operational moderate resolution-imaging capabilities following the legacy of the advanced very high-resolution radiometer series on NOAA satellites and Terra and Aqua Moderate-Resolution Imaging Spectroradiometer for NASA's Earth Observing system. VIIRS provides significant enhancements to the operational environmental monitoring and numerical weather forecasting, with 22 imaging and radiometric bands covering wavelengths from 0.41 to 12.5 microns, providing the sensor data records for 23 environmental data records including aerosol, cloud properties, fire, albedo, snow and ice, vegetation, sea surface temperature, ocean color, and nigh-time visible-light-related applications. Preliminary results from the on-orbit verification in the postlaunch check-out and intensive calibration and validation have shown that VIIRS is performing well and producing high-quality images. This paper provides an overview of the onorbit performance of VIIRS, the calibration/validation (cal/val) activities and methodologies used. It presents an assessment of the sensor initial on-orbit calibration and performance based on the efforts from the VIIRS-SDR team. Known anomalies, issues, and future calibration efforts, including the long-term monitoring, and intercalibration are also discussed.

The Role of Orbital Forcing in the Early-Middle Pleistocene Transition: Continuing the Precession Verses Obliquity Debate

NASA Astrophysics Data System (ADS)

Maslin, M. A.; Brierley, C. M.

2015-12-01

The Early-Middle Pleistocene Transition (EMPT) is the term used to describe the prolongation and intensification of glacial-interglacial climate cycles that initiated after 900,000 years ago. During the transition glacial-interglacial cycles shift from lasting 41,000 years to an average of 100,000 years. The structure of these glacial-interglacial cycles shifts from smooth to more abrupt 'saw-toothed' like transitions. In fact we argue there is shift from a bimodal climate to a tripartite climate system (see Figure). Despite eccentricity having by far the weakest influence on insolation received at the Earth's surface of any of the orbital parameters; it is often assumed to be the primary driver of the post-EMPT 100,000 years climate cycles because of the similarity in duration. The traditional solution to this is to call for a highly nonlinear response by the global climate system to eccentricity. This 'eccentricity myth' is due to an artefact of spectral analysis which means that the last 8 glacial-interglacial average out at about 100,000 years in length despite ranging from 80,000 to 120,000 years. With the realisation that eccentricity is not the major driving force a debate has emerged as to whether precession or obliquity controlled the timing of the most recent glacial-interglacial cycles. Some argue that post-EMPT deglaciations occurred every four or five precessional cycle while others argue it is every second or third obliquity cycle. We review these current theories and suggest that though phase-locking between orbital forcing and global ice volume may occur and seem to primarily driven by the timing of precession; the chaotic nature of the climate system response means the relationship is not consistent through the last 900,000 years.

Low lift-to-drag aero-assisted orbit transfer vehicles

NASA Technical Reports Server (NTRS)

Andrews, D. G.; Savage, R. T.

1984-01-01

The results of systems analysis conducted on low life drag ratio (L/D) aero-assisted orbit transfer vehicle (AOTV's) are presented. The objectives for this class of vehicle and formulate technology development plans and funding levels to bring the required technologies to readiness levels, as well as develop a credible decision data base encompassing the entire range of low L/D concepts for use in future NASA Aeroassist Orbit Transfer Vehicles studies. Each candidate low L/D concept, the aerobrake, the lifting brake, and the aeromaneuvering concept could be made to work with technologies achievable by the early 1990's. All concepts require flexible structure with flexible thermal protection system (TPS) to be successfully integrated into the shuttle orbiter for launch, all required improvements in guidance and control to fly the dispersed atmospheres at high altitude, and all concepts had potential to evolve from ground-based to space-based operations.

Frank Ross's Early Orbits of the First Irregular Satellites of Saturn and Jupiter

NASA Astrophysics Data System (ADS)

Osterbrock, Donald E.

2006-12-01

Frank E. Ross, later the inventor of the wide-angle lens, photographic photometer, and correcting lens for large reflecting telescopes, developed for the 200-inch, that bear his name, was also an expert on celestial mechanics. After earning his PhD at Berkeley in 1901, he worked in Washington as chief assistant to Simon Newcomb, the leading astronomer of his time, until the latter's death in 1909. W. H. Pickering, who had discovered Phoebe, the first distant, irregular satellite of Saturn, was unable to calculate an orbit for it. He asked Newcomb to do it, but the "grim dean of American astronomy" was too busy, and turned the task over to Ross to do, mostly on his own time. The young assistant succeeded, but spent many sleepless nights on the job. He and his brother Walter were also running a cigar store in Washington at the time. Charles D. Perrine at Lick Observatory discovered J VI and J VII, the first two similar satellites of Jupiter, in 1904 and 1905, and could not obtain satisfactory orbits for them either, even with Director W. W. Campbell's help. Ross then calculated their orbits also, again at a tremendous cost of effort. He used log tables, pencil and paper, and a simple adding machine for his computing tasks, as all "computers" (persons) did at that time. These three satellites were the first to be discovered by photography.

Comparison of Low Earth Orbit and Geosynchronous Earth Orbits

NASA Technical Reports Server (NTRS)

Drummond, J. E.

1980-01-01

The technological, environmental, social, and political ramifications of low Earth orbits as compared to geosynchronous Earth orbits for the solar power satellite (SPS) are assessed. The capital cost of the transmitting facilities is dependent on the areas of the antenna and rectenna relative to the requirement of high efficiency power transmission. The salient features of a low orbit Earth orbits are discussed in terms of cost reduction efforts.

Orbit determination singularities in the Doppler tracking of a planetary orbiter

NASA Technical Reports Server (NTRS)

Wood, L. J.

1985-01-01

On a number of occasions, spacecraft launched by the U.S. have been placed into orbit about the moon, Venus, or Mars. It is pointed out that, in particular, in planetary orbiter missions two-way coherent Doppler data have provided the principal data type for orbit determination applications. The present investigation is concerned with the problem of orbit determination on the basis of Doppler tracking data in the case of a spacecraft in orbit about a natural body other than the earth or the sun. Attention is given to Doppler shift associated with a planetary orbiter, orbit determination using a zeroth-order model for the Doppler shift, and orbit determination using a first-order model for the Doppler shift.

Measurements of the STS orbiter's angular stability during in-orbit operations

NASA Technical Reports Server (NTRS)

Neupert, Werner M.; Epstein, Gabriel L.; Houston, James; Zarechnak, Andrew

1995-01-01

We report on measurements of the angular stability, commonly called 'jitter', of the STS Orbiter during normal operations in space. Measurements were carried out by measuring optically the Orbiter's roll and pitch orientation relative to the solar vector as the orbiter was held in a -Z(sub 0) solar inertial orientation (orbiter bay oriented toward the Sun). We also report observations of an interesting perturbation to the orbiter's orientation noted by the crew during the STS-60 mission. These data may be useful in analyzing the in-orbit response of the Orbiter to thruster firings and other applied torques, and may aid in the planning of future experiments that require fine-pointed operations by the orbiter.

Overall view of the Orbiter Servicing Structure within the Orbiter ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Overall view of the Orbiter Servicing Structure within the Orbiter Processing Facility at Kennedy Space Center. Can you see any hint of the Orbiter Discovery? It is in there. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

The Origin of Pluto's Orbit: Implications for the Solar System Beyond Neptune

NASA Technical Reports Server (NTRS)

Malhotra, Renu

1995-01-01

The origin of the highly eccentric, inclined, and resonance-locked orbit of Pluto has long been a puzzle. A possible explanation has been proposed recently which suggests that these extraordinary orbital properties may be a natural consequence of the formation and early dynamical evolution of the outer solar system. A resonance capture mechanism is possible during the clearing of the residual planetesimal debris and the formation of the Oort Cloud of comets by planetesimal mass loss from the vicinity of the giant planets. If this mechanism were in operation during the early history of the planetary system, the entire region between the orbit of Neptune and approximately 50 AU would have been swept by first-order mean motion resonances. Thus, resonance capture could occur not only for Pluto, but quite generally for other trans-Neptunian small bodies. Some consequences of this evolution for the present-day dynamical structure of the trans-Neptunian region are (1) most of the objects in the region beyond Neptune and up to approximately 50 AU exist in very narrow zones located at orbital resonances with Neptune (particularly the 3:2 and the 2:1 resonances); and (2) these resonant objects would have significantly large eccentricities. The distribution of objects in the Kuiper Belt as predicted by this theory is presented here.

Experience Gained From Launch and Early Orbit Support of the Rossi X-Ray Timing Explorer (RXTE)

NASA Technical Reports Server (NTRS)

Fink, D. R.; Chapman, K. B.; Davis, W. S.; Hashmall, J. A.; Shulman, S. E.; Underwood, S. C.; Zsoldos, J. M.; Harman, R. R.

1996-01-01

this paper reports the results to date of early mission support provided by the personnel of the Goddard Space Flight Center Flight Dynamics Division (FDD) for the Rossi X-Ray Timing Explorer (RXTE) spacecraft. For this mission, the FDD supports onboard attitude determination and ephemeris propagation by supplying ground-based orbit and attitude solutions and calibration results. The first phase of that support was to provide launch window analyses. As the launch window was determined, acquisition attitudes were calculated and calibration slews were planned. postlaunch, these slews provided the basis for ground determined calibration. Ground determined calibration results are used to improve the accuracy of onboard solutions. The FDD is applying new calibration tools designed to facilitate use of the simultaneous, high-accuracy star observations from the two RXTE star trackers for ground attitude determination and calibration. An evaluation of the performance of these tools is presented. The FDD provides updates to the onboard star catalog based on preflight analysis and analysis of flight data. The in-flight results of the mission support in each area are summarized and compared with pre-mission expectations.

Deadly Sunflower Orbits

NASA Astrophysics Data System (ADS)

Hamilton, Douglas P.

2018-04-01

Solar radiation pressure is usually very effective at removing hazardous millimeter-sized debris from distant orbits around asteroidsand other small solar system bodies (Hamilton and Burns 1992). Theprimary loss mechanism, driven by the azimuthal component of radiationpressure, is eccentricity growth followed by a forced collision withthe central body. One large class of orbits, however, neatly sidestepsthis fate. Orbits oriented nearly perpendicular to the solar directioncan maintain their face-on geometry, oscillating slowly around a stableequilibrium orbit. These orbits, designated sunflower orbits, arerelated to terminator orbits studied by spacecraft mission designers(Broschart etal. 2014).Destabilization of sunflower orbits occurs only for particles smallenough that radiation pressure is some tens of percent the strength ofthe central body's direct gravity. This greatly enhanced stability,which follows from the inability of radiation incident normal to theorbit to efficiently drive eccentricities, presents a threat tospacecraft missions, as numerous dangerous projectiles are potentiallyretained in orbit. We have investigated sunflower orbits insupport of the New Horizons, Aida, and Lucy missions and find thatthese orbits are stable for hazardous particle sizes at asteroids,comets, and Kuiper belt objects of differing dimensions. Weinvestigate the sources and sinks for debris that might populate suchorbits, estimate timescales and equilibrium populations, and willreport on our findings.

Feasibility study of a zero-gravity (orbital) atmospheric cloud physics experiments laboratory

NASA Technical Reports Server (NTRS)

Hollinden, A. B.; Eaton, L. R.

1972-01-01

A feasibility and concepts study for a zero-gravity (orbital) atmospheric cloud physics experiment laboratory is discussed. The primary objective was to define a set of cloud physics experiments which will benefit from the near zero-gravity environment of an orbiting spacecraft, identify merits of this environment relative to those of groundbased laboratory facilities, and identify conceptual approaches for the accomplishment of the experiments in an orbiting spacecraft. Solicitation, classification and review of cloud physics experiments for which the advantages of a near zero-gravity environment are evident are described. Identification of experiments for potential early flight opportunities is provided. Several significant accomplishments achieved during the course of this study are presented.

Latitudinal diversity gradients in Mesozoic non-marine turtles

NASA Astrophysics Data System (ADS)

Nicholson, David B.; Holroyd, Patricia A.; Valdes, Paul; Barrett, Paul M.

2016-11-01

The latitudinal biodiversity gradient (LBG)-the pattern of increasing taxonomic richness with decreasing latitude-is prevalent in the structure of the modern biota. However, some freshwater taxa show peak richness at mid-latitudes; for example, extant Testudines (turtles, terrapins and tortoises) exhibit their greatest diversity at 25° N, a pattern sometimes attributed to recent bursts of climatically mediated species diversification. Here, we test whether this pattern also characterizes the Mesozoic distribution of turtles, to determine whether it was established during either their initial diversification or as a more modern phenomenon. Using global occurrence data for non-marine testudinate genera, we find that subsampled richness peaks at palaeolatitudes of 15-30° N in the Jurassic, 30-45° N through the Cretaceous to the Campanian, and from 30° to 60° N in the Maastrichtian. The absence of a significant diversity peak in southern latitudes is consistent with results from climatic models and turtle niche modelling that demonstrate a dearth of suitable turtle habitat in Gondwana during the Jurassic and Late Cretaceous. Our analyses confirm that the modern testudinate LBG has a deep-time origin and further demonstrate that LBGs are not always expressed as a smooth, equator-to-pole distribution.

Compositional variation of glauconites in Upper Cretaceous-Paleogene sedimentary iron-ore deposits in South-eastern Western Siberia

NASA Astrophysics Data System (ADS)

Rudmin, Maxim; Banerjee, Santanu; Mazurov, Aleksey

2017-06-01

Glauconite occurs either as unaltered greenish or as altered brownish variety in Upper Cretaceous-Palaeocene sediments in the southeastern corner of Western Siberia. Studied section within the Bakchar iron-ore deposit includes Ipatovo, Slavgorod, Gan'kino and Lyulinvor formations, which are represented by sandstones, siltstones, claystones and oolitic ironstones of coastal-marine facies. The origin of unaltered glauconite is explained by the ;verdissement theory;. Transgressions during Lower Coniacian, Santonian and Campanian favored the formation of unaltered glauconites in dysoxic to anoxic conditions. Subaerial exposure of glauconite resulted in leaching of potassium, oxidation of iron and formation of iron hydroxides in Upper Coniacian, Maastrichtian and Palaeocene. Glauconite ultimately converts to leptochlorite and hydrogoethite by this alteration. Abundant microscopic gold inclusions, besides sulphides, sulphates, oxides and silicates characterize this glauconite. Mineral inclusions include precious, rare metals and non-ferrous metals. The concentration of gold in glauconite may be as high as 42.9 ppb. Abundant inclusions of various compositions in glauconites indicate enrichment of marine sediments in precious and non-precious metals. While major element composition of glauconites is affected by subaerial exposure, the broadly similar micro-inclusions in both altered and unaltered varieties are possibly related to the comparatively immobile nature of REE and trace elements.

Orbital Perturbations of the Galilean Satellites during Planetary Encounters

NASA Astrophysics Data System (ADS)

Deienno, Rogerio; Nesvorný, David; Vokrouhlický, David; Yokoyama, Tadashi

2014-08-01

The Nice model of the dynamical instability and migration of the giant planets can explain many properties of the present solar system, and can be used to constrain its early architecture. In the jumping-Jupiter version of the Nice model, required from the terrestrial planet constraint and dynamical structure of the asteroid belt, Jupiter has encounters with an ice giant. Here, we study the survival of the Galilean satellites in the jumping-Jupiter model. This is an important concern because the ice-giant encounters, if deep enough, could dynamically perturb the orbits of the Galilean satellites and lead to implausible results. We performed numerical integrations where we tracked the effect of planetary encounters on the Galilean moons. We considered three instability cases from Nesvorný & Morbidelli that differed in the number and distribution of encounters. We found that in one case, where the number of close encounters was relatively small, the Galilean satellite orbits were not significantly affected. In the other two, the orbital eccentricities of all moons were excited by encounters, Callisto's semimajor axis changed, and, in a large fraction of trials, the Laplace resonance of the inner three moons was disrupted. The subsequent evolution by tides damps eccentricities and can recapture the moons in the Laplace resonance. A more important constraint is represented by the orbital inclinations of the moons, which can be excited during the encounters and not appreciably damped by tides. We find that one instability case taken from Nesvorný & Morbidelli clearly does not meet this constraint. This shows how the regular satellites of Jupiter can be used to set limits on the properties of encounters in the jumping-Jupiter model, and help us to better understand how the early solar system evolved.

Real-time optimal guidance for orbital maneuvering.

NASA Technical Reports Server (NTRS)

Cohen, A. O.; Brown, K. R.

1973-01-01

A new formulation for soft-constraint trajectory optimization is presented as a real-time optimal feedback guidance method for multiburn orbital maneuvers. Control is always chosen to minimize burn time plus a quadratic penalty for end condition errors, weighted so that early in the mission (when controllability is greatest) terminal errors are held negligible. Eventually, as controllability diminishes, the method partially relaxes but effectively still compensates perturbations in whatever subspace remains controllable. Although the soft-constraint concept is well-known in optimal control, the present formulation is novel in addressing the loss of controllability inherent in multiple burn orbital maneuvers. Moreover the necessary conditions usually obtained from a Bolza formulation are modified in this case so that the fully hard constraint formulation is a numerically well behaved subcase. As a result convergence properties have been greatly improved.

Forbidden tangential orbit transfers between intersecting Keplerian orbits

NASA Technical Reports Server (NTRS)

Burns, Rowland E.

1990-01-01

The classical problem of tangential impulse transfer between coplanar Keplerian orbits is addressed. A completely analytic solution which does not rely on sequential calculation is obtained and this solution is used to demonstrate that certain initially chosen angles can produce singularities in the parameters of the transfer orbit. A necessary and sufficient condition for such singularities is that the initial and final orbits intersect.

Feasibility study for the Cryogenic Orbital Nitrogen Experiment (CONE)

NASA Technical Reports Server (NTRS)

Bell, R. S.; Crouch, M. A.; Hanna, G. J.; Cady, E. C.; Meserole, J. S.

1991-01-01

An improved understanding of low gravity subcritical cryogenic fluid behavior is critical for the continued development of space based systems. Although early experimental programs provided some fundamental understanding of zero gravity cryogenic fluid behavior, more extensive flight data are required to design space based cryogenic liquid storage and transfer systems with confidence. As NASA's mission concepts evolve, the demand for optimized in-space cryogenic systems is increasing. Cryogenic Orbital Nitrogen Experiment (CONE) is an attached shuttle payload experiment designed to address major technological issues associated with on-orbit storage and supply of cryogenic liquids. During its 7 day mission, CONE will conduct experiments and technology demonstrations in active and passive pressure control, stratification and mixing, liquid delivery and expulsion efficiency, and pressurant bottle recharge. These experiments, conducted with liquid nitrogen as the test fluid, will substantially extend the existing low gravity fluid data base and will provide future system designers with vital performance data from an orbital environment.

NASA logo painted on orbiter Endeavour

NASA Technical Reports Server (NTRS)

1998-01-01

A KSC worker paints the NASA logo on the port wing of the orbiter Endeavour, which is scheduled to launch in December for STS-88. The paint is a special pigment that takes 18 hours to dry; the whole process takes approximately two weeks to complete. The NASA logo, termed 'meatball,' was originally designed in the late 1950s. It symbolized NASA's role in aeronautics and space in the early years of the agency. The original design included a white border surrounding it. The border was dropped for the Apollo 7 mission in October 1968, replaced with royal blue to match the background of the emblem. In 1972 the logo was replaced by a simple and contemporary design -- the 'worm' -- which was retired from use last year. NASA reverted to its original logo in celebration of the agency's 40th anniversary in October, and the 'golden age' of America's space program. All the orbiters will bear the new logo.

Carbon Cycle Dynamics through the Early Eocene Climatic Optimum: Orbital Couplings to Lacustrine Cycling

NASA Astrophysics Data System (ADS)

Rosengard, S. Z.; Grogan, D. S.; Whiteside, J. H.; van Keuren, M.; Musher, D.

2010-12-01

The early Eocene represents the most recent hothouse climate state of Earth history, a period during which Earth’s surface temperatures warmed and reached a steady peak at the Early Eocene Climatic Optimum (EECO), 53.5-50 Ma. Interspersed through the primary warming interval were several hyperthermals, or rapid peaks in surface temperature and pulses of carbon dioxide into the atmosphere, followed by rapid declines, lasting 10^4 to 10^5 years. Various hypotheses have been offered to explain the climatic triggers during the hothouse interval, including changes in ocean circulation, methane release from hydrates, volcanism, and turnover of terrestrial organic matter, implicating various couplings and feedbacks in the global carbon cycle. The present study investigates the prevailing changes in carbon cycle dynamics that occurred during a specific subinterval of the Early Eocene Climatic Optimum. We sampled a carbon-rich 300-ft ( 1100 kyr) section of lacustrine Green River Formation sediments from the TOSCO core in the Uinta Basin at a one-foot resolution for organic carbon content and δ^{13}C. The compiled data comprise a high-resolution profile of total organic carbon and isotopic organic carbon composition through the section, showing cyclic patterns that we hypothesize reflect orbital signals. Bulk isotopic carbon and shale oil measurements from an earlier Fischer Assay across TOSCO’s entire 1030-ft core were then filtered using the expected frequency of a 23-kyr precession cycle. The overlaid cycles reveal δ^{13}C and oil content to be anti-phase through the 300-ft section, except for an interval of 50 feet (180 kyr) from the Mahogany Zone to the B-groove of the core, where the two measurements are in-phase. Given that shale oil, a proxy for lake primary productivity and carbon burial, and δ^{13}C typically correlate inversely, this short, 180-kyr interval of in-phase variation suggests a significant alteration in the local carbon cycle. These preliminary

Orbiter Gap Filler Bending Model for Re-entry

NASA Technical Reports Server (NTRS)

Campbell, Charles H.

2007-01-01

Pressure loads on a protruding gap filler during an Orbiter reentry are investigated to evaluate the likelihood of extraction due to pressure loads, and to ascertain how much bending will be induced by re-entry pressure loads. Oblique shock wave theory is utilized to develop a representation of the pressure loads induced on a gap filler for the ISSHVFW trajectory, representative of a heavy weight ISS return. A free body diagram is utilized to react the forces induced by the pressure forces. Preliminary results developed using these methods demonstrate that pressure loads, alone, are not likely causes of gap filler extraction during reentry. Assessment of the amount a gap filler will bend over is presented. Implications of gap filler bending during re-entry include possible mitigation of early boundary layer transition concerns, uncertainty in ground based measurement of protruding gap fillers from historical Orbiter flight history, and uncertainty in the use of Orbiter gap fillers for boundary layer prediction calibration. Authors will be added to the author list as appropriate.

Frozen Orbits-Near Constant or Beneficially Varying Orbital Parameters.

DTIC Science & Technology

1986-05-15

89 6.3 Equatorial Near-Circular Orbits ............................... 92 6.4 Stable and Unstable Equilibrium Points ...Angle Libration Period......................................... 78 5-2 Lunar Gravitational Effect on Near-Circular Orbits .................... 80 5-3...6-1 Period of Oscillation about the Stable Equilibrium Point ............... 102 FIGURES Figure 2.1 Orbital Parameters

Dawn Orbit Determination Team: Trajectory and Gravity Prediction Performance During Vesta Science Phases

NASA Technical Reports Server (NTRS)

Kennedy, Brian; Abrahamson, Matt; Ardito, Alessandro; Han, Dongsuk; Haw, Robert; Mastrodemos, Nicholas; Nandi, Sumita; Park, Ryan; Rush, Brian; Vaughan, Andrew

2013-01-01

The Dawn spacecraft was launched on September 27th, 2007. Its mission is to consecutively rendezvous with and observe the two largest bodies in the asteroid belt, Vesta and Ceres. It has already completed over a year's worth of direct observations of Vesta (spanning from early 2011 through late 2012) and is currently on a cruise trajectory to Ceres, where it will begin scientific observations in mid-2015. Achieving this data collection required careful planning and execution from all spacecraft teams. Dawn's Orbit Determination (OD) team was tasked with accurately predicting the trajectory of the Dawn spacecraft during the Vesta science phases, and also determining the parameters of Vesta to support future science orbit design. The future orbits included the upcoming science phase orbits as well as the transfer orbits between science phases. In all, five science phases were executed at Vesta, and this paper will describe some of the OD team contributions to the planning and execution of those phases.

Reconstruction of Midface and Orbital Wall Defects After Maxillectomy and Orbital Content Preservation With Titanium Mesh and Fascia Lata: 3-Year Follow-Up.

PubMed

Motiee-Langroudi, Maziar; Harirchi, Iraj; Amali, Amin; Jafari, Mehrdad

2015-12-01

To describe the authors' experience in the reconstruction of patients after total maxillectomy with preservation of orbital contents for maxillary tumors using titanium mesh and autogenous fascia lata, where no setting for free flap reconstruction is available. Twelve consecutive patients with paranasal sinus tumors underwent total maxillectomy without orbital exenterations and primary reconstruction. The defects were reconstructed by titanium mesh in combination with autogenous fascia lata in the orbital floor performed by 1 surgical team. Titanium mesh (0.2 mm thick) was contoured and fixed to reconstruct the orbital floor and obtain midface projection. Fascia lata was used to cover the titanium mesh along the orbital floor to prevent fat entrapment in the mesh holes. The most common pathology was squamous cell carcinoma (50%). Patients' mean age was 45.66 years (33 to 74 yr). The mean follow-up period was 35.2 months (30 to 49 months). During follow-up, no infection or foreign body reaction was encountered. Extrusion of titanium mesh occurred in 4 patients who underwent postoperative radiotherapy. Two cases of mild diplopia at extreme gaze occurred early during the postoperative period that resolved after a few months. Placing fascia lata between the titanium mesh surface of the orbital implant and the orbital contents was successful in preventing long-term diplopia or dystopia. Nevertheless, exposure of the titanium implant through the skin surface represented a complication of this technique in 25% of patients. Further studies are required with head-to-head comparisons of artificial materials and free flaps for reconstruction of maxillectomy defects. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Rashba spin-orbit coupling and orbital chirality in magnetic bilayers

NASA Astrophysics Data System (ADS)

Lee, Hyun-Woo

2013-03-01

The phenomenon of the Rashba spin-orbit coupling is examined theoretically for an ultrathin magnetic layer in contact with a non-magnetic heavy metal layer. From first-principles calculation, large Rashba parameter of order 1 eV .Å is obtained, which is strong enough to generate large spin transfer torque of spin-orbit coupling origin. Large Rashba parameter is attributed to the orbital mixing of 3 d magnetic atoms and non-magnetic heavy elements with significant atomic spin-orbit coupling. Interestingly the magnitude and sign of the parameter vary from energy bands to bands, which we attribute to band-specific chiral ordering of orbital angular momentum. Through a simple tight-binding model analysis, we demonstrate that d-orbital hybridization allowed by the breaking of structural inversion symmetry generates band-specific chiral ordering of orbital angular momentum, which combines with atomic spin-orbit coupling to give rise to band-specific Rashba parameter. The band-dependence of the Rashba parameter is discussed in connection with recent experiments and we argue that the dependence may be utilized to enhance device application potentials. This work is supported by NRF grant (2010-0008529, 2011-0015631, 2010-0014109, 2011-0030789).

Assembling a Space Station in orbit

NASA Technical Reports Server (NTRS)

Brand, Vance D.; Lounge, J. Michael; Walker, David M.

1990-01-01

The factors affecting the degree of difficulty of assembling a Space Station in orbit and ways of arriving at the optimum construction solution are briefly reviewed and applied to the Space Station Freedom (SSF). The assembly of the SSF navigation and control systems and the relevant tools and methods are examined along with the characteristics of early assembly flights. The most significant challenges facing the construction of the SSF are discussed, and new technologies which will be incorporated into the SSF are briefly considered.

Jovian system science issues and implications for a Mariner Jupiter Orbiter mission

NASA Technical Reports Server (NTRS)

Beckman, J. C.; Miner, E. D.

1975-01-01

Science goals for missions to Jupiter in the early 1980's are reviewed and a case is made for the science community to play the key role in assigning relative priorities for these goals. A reference set of measurement requirements and their priorities is established and those high priority goals that are most demanding on spacecraft and mission design are used to develop a reference mission concept. An orbiter mission is required to satisfy a majority of the measurements, and a spacecraft data handling capability as least equivalent to the Mariner Jupiter/Saturn spacecraft is the major system design driver. This reference Mission Concept is called Mariner Jupiter Orbiter. The remaining measurement requirements are reviewed in light of the potential science return of this mission, and certain options are developed to augment this science return. Two attractive options fulfill high priority objectives not achieved by the reference Mariner Jupiter Orbiter mission alone: an atmospheric entry probe, released prior to orbit insertion; and a daughter satellite dedicated to particle and fields measurements, ejected into an independent orbit about Jupiter.

Orbit Software Suite

NASA Technical Reports Server (NTRS)

Osgood, Cathy; Williams, Kevin; Gentry, Philip; Brownfield, Dana; Hallstrom, John; Stuit, Tim

2012-01-01

Orbit Software Suite is used to support a variety of NASA/DM (Dependable Multiprocessor) mission planning and analysis activities on the IPS (Intrusion Prevention System) platform. The suite of Orbit software tools (Orbit Design and Orbit Dynamics) resides on IPS/Linux workstations, and is used to perform mission design and analysis tasks corresponding to trajectory/ launch window, rendezvous, and proximity operations flight segments. A list of tools in Orbit Software Suite represents tool versions established during/after the Equipment Rehost-3 Project.

A new species of Ischyodus (Chondrichthyes: Holocephali: Callorhynchidae) from Upper Maastrichtian Shallow marine facies of the Fox Hills and Hell Creek Formations, Williston basin, North Dakota, USA

USGS Publications Warehouse

Hoganson, J.W.; Erickson, J.M.

2005-01-01

A new species of chimaeroid, Ischyodus rayhaasi sp. nov., is described based primarily upon the number and configuration of tritors on palatine and mandibular tooth plates. This new species is named in honour of Mr Raymond Haas. Fossils of I. rayhaasi have been recovered from the Upper Maastrichtian Fox Hills Formation and the Breien Member and an unnamed member of the Hell Creek Formation at sites in south-central North Dakota and north-central South Dakota, USA. Ischyodus rayhaasi inhabited shallow marine waters in the central part of the Western Interior Seaway during the latest Cretaceous. Apparently it was also present in similar habitats at that time in the Volga region of Russia. Ischyodus rayhaasi is the youngest Cretaceous species Ischyodus known to exist before the Cretaceous/Tertiary extinction, and the species apparently did not survive that event. It was replaced by Ischyodus dolloi, which is found in the Paleocene Cannonball Formation of the Williston Basin region of North Dakota and is widely distributed elsewhere. ?? The Palaeontological Association.

Flight Demonstrations of Orbital Space Plane (OSP) Technologies

NASA Technical Reports Server (NTRS)

Turner, Susan

2003-01-01

The Orbital Space Plane (OSP) Program embodies NASA s priority to transport Space Station crews safely, reliably, and affordably, while it empowers the Nation s greater strategies for scientific exploration and space leadership. As early in the development cycle as possible, the OSP will provide crew rescue capability, offering an emergency ride home from the Space Station, while accommodating astronauts who are deconditioned due to long- duration missions, or those that may be ill or injured. As the OSP Program develops a fully integrated system, it will use existing technologies and employ computer modeling and simulation. Select flight demonstrator projects will provide valuable data on launch, orbital, reentry, and landing conditions to validate thermal protection systems, autonomous operations, and other advancements, especially those related to crew safety and survival.

Effects of aerodynamic heating and TPS thermal performance uncertainties on the Shuttle Orbiter

NASA Technical Reports Server (NTRS)

Goodrich, W. D.; Derry, S. M.; Maraia, R. J.

1980-01-01

A procedure for estimating uncertainties in the aerodynamic-heating and thermal protection system (TPS) thermal-performance methodologies developed for the Shuttle Orbiter is presented. This procedure is used in predicting uncertainty bands around expected or nominal TPS thermal responses for the Orbiter during entry. Individual flowfield and TPS parameters that make major contributions to these uncertainty bands are identified and, by statistical considerations, combined in a manner suitable for making engineering estimates of the TPS thermal confidence intervals and temperature margins relative to design limits. Thus, for a fixed TPS design, entry trajectories for future Orbiter missions can be shaped subject to both the thermal-margin and confidence-interval requirements. This procedure is illustrated by assessing the thermal margins offered by selected areas of the existing Orbiter TPS design for an entry trajectory typifying early flight test missions.

Long-orbital-period Prepolars Containing Early K-type Donor Stars. Bottleneck Accretion Mechanism in Action

NASA Astrophysics Data System (ADS)

Tovmassian, G.; González–Buitrago, D.; Zharikov, S.; Reichart, D. E.; Haislip, J. B.; Ivarsen, K. M.; LaCluyze, A. P.; Moore, J. P.; Miroshnichenko, A. S.

2016-03-01

We studied two objects identified as cataclysmic variables (CVs) with periods exceeding the natural boundary for Roche-lobe-filling zero-age main sequence (ZAMS) secondary stars. We present observational results for V1082 Sgr with a 20.82 hr orbital period, an object that shows a low luminosity state when its flux is totally dominated by a chromospherically active K star with no signs of ongoing accretion. Frequent accretion shutoffs, together with characteristics of emission lines in a high state, indicate that this binary system is probably detached, and the accretion of matter on the magnetic white dwarf takes place through stellar wind from the active donor star via coupled magnetic fields. Its observational characteristics are surprisingly similar to V479 And, a 14.5 hr binary system. They both have early K-type stars as donor stars. We argue that, similar to the shorter-period prepolars containing M dwarfs, these are detached binaries with strong magnetic components. Their magnetic fields are coupled, allowing enhanced stellar wind from the K star to be captured and channeled through the bottleneck connecting the two stars onto the white dwarf’s magnetic pole, mimicking a magnetic CV. Hence, they become interactive binaries before they reach contact. This will help to explain an unexpected lack of systems possessing white dwarfs with strong magnetic fields among detached white+red dwarf systems.

Orbital abscess during endodontic treatment: a case report.

PubMed

de Medeiros, Eduardo Henrique Pantosso; Pepato, André Oliveira; Sverzut, Cássio Edvard; Trivellato, Alexandre Elias

2012-11-01

Orbital infections may result in permanent morbidity because of the severity of infection. Furthermore, delayed diagnosis or treatment of orbital infections can lead to intracranial complications and even death. The majority of orbital infections develop from paranasal sinus infections, cutaneous infections, and periorbital trauma. Dacryocystitis and odontogenic infection are also accounted as potential etiologies but are scarcely reported in scientific literature. The patient revealed a history of having endodontic treatment on left maxillary second molar performed 2 weeks previously. Moreover, she exhibited signs of facial pain accompanied by sinusitis symptoms, fever, and nasal obstruction the week after this endodontic procedure. The patient presented proptosis, impairment of ocular motility to the right side, facial tenderness, palpebral erythema, and referred decreased visual acuity. Intraoral exam revealed root fragments of left maxillary first molar and an extensive carious lesion on left maxillary second molar. Computed tomography enabled the observation of frontal sinus, left-sided maxillary, opacity of sphenoidal and ethmoidal sinuses, and apical lesion of left maxillary first and second molars, all suggesting the presence of their apex in the maxillary sinus. In addition, images revealed ocular proptosis and presence of high-density areas suggestive of pus in the medial orbital wall region. The patient was submitted to surgical drainage under general anesthesia approximately 8 hours after the clinical evaluation. Early detection of orbital infection, proper diagnostic tests, and treatment may provide successful outcomes of this rarely occurring disease. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Orbital Spacecraft Consumables Resupply System (OSCRS). Volume 3: Program Cost Estimate

NASA Technical Reports Server (NTRS)

Perry, D. L.

1986-01-01

A cost analysis for the design, development, qualification, and production of the monopropellant and bipropellant Orbital Spacecraft Consumable Resupply System (OSCRS) tankers, their associated avionics located in the Orbiter payload bay, and the unique ground support equipment (GSE) and airborne support equipment (ASE) required to support operations is presented. Monopropellant resupply for the Gamma Ray Observatory (GRO) in calendar year 1991 is the first defined resupply mission with bipropellant resupply missions expected in the early to mid 1990's. The monopropellant program estimate also includes contractor costs associated with operations support through the first GRO resupply mission.

Impact of GNSS orbit modeling on LEO orbit and gravity field determination

NASA Astrophysics Data System (ADS)

Arnold, Daniel; Meyer, Ulrich; Sušnik, Andreja; Dach, Rolf; Jäggi, Adrian

2017-04-01

On January 4, 2015 the Center for Orbit Determination in Europe (CODE) changed the solar radiation pressure modeling for GNSS satellites to an updated version of the empirical CODE orbit model (ECOM). Furthermore, since September 2012 CODE operationally computes satellite clock corrections not only for the 3-day long-arc solutions, but also for the non-overlapping 1-day GNSS orbits. This provides different sets of GNSS products for Precise Point Positioning, as employed, e.g., in the GNSS-based precise orbit determination of low Earth orbiters (LEOs) and the subsequent Earth gravity field recovery from kinematic LEO orbits. While the impact of the mentioned changes in orbit modeling and solution strategy on the GNSS orbits and geophysical parameters was studied in detail, their implications on the LEO orbits were not yet analyzed. We discuss the impact of the update of the ECOM and the influence of 1-day and 3-day GNSS orbit solutions on zero-difference LEO orbit and gravity field determination, where the GNSS orbits and clock corrections, as well as the Earth rotation parameters are introduced as fixed external products. Several years of kinematic and reduced-dynamic orbits for the two GRACE LEOs are computed with GNSS products based on both the old and the updated ECOM, as well as with 1- and 3-day GNSS products. The GRACE orbits are compared by means of standard validation measures. Furthermore, monthly and long-term GPS-only and combined GPS/K-band gravity field solutions are derived from the different sets of kinematic LEO orbits. GPS-only fields are validated by comparison to combined GPS/K-band solutions, while the combined solutions are validated by analysis of the formal errors, as well as by comparing them to the combined GRACE solutions of the European Gravity Service for Improved Emergency Management (EGSIEM) project.

Correlating carbon and oxygen isotope events in early to middle Miocene shallow marine carbonates in the Mediterranean region using orbitally tuned chemostratigraphy and lithostratigraphy

PubMed Central

Piller, Werner E.; Reuter, Markus; Harzhauser, Mathias

2015-01-01

Abstract During the Miocene prominent oxygen isotope events (Mi‐events) reflect major changes in glaciation, while carbonate isotope maxima (CM‐events) reflect changes in organic carbon burial, particularly during the Monterey carbon isotope excursion. However, despite their importance to the global climate history they have never been recorded in shallow marine carbonate successions. The Decontra section on the Maiella Platform (central Apennines, Italy), however, allows to resolve them for the first time in such a setting during the early to middle Miocene. The present study improves the stratigraphic resolution of parts of the Decontra section via orbital tuning of high‐resolution gamma ray (GR) and magnetic susceptibility data to the 405 kyr eccentricity metronome. The tuning allows, within the established biostratigraphic, sequence stratigraphic, and isotope stratigraphic frameworks, a precise correlation of the Decontra section with pelagic records of the Mediterranean region, as well as the global paleoclimatic record and the global sea level curve. Spectral series analyses of GR data further indicate that the 405 kyr orbital cycle is particularly well preserved during the Monterey Event. Since GR is a direct proxy for authigenic uranium precipitation during increased burial of organic carbon in the Decontra section, it follows the same long‐term orbital pacing as observed in the carbon isotope records. The 405 kyr GR beat is thus correlated with the carbon isotope maxima observed during the Monterey Event. Finally, the Mi‐events can now be recognized in the δ18O record and coincide with plankton‐rich, siliceous, or phosphatic horizons in the lithology of the section. PMID:27546980

Correlating carbon and oxygen isotope events in early to middle Miocene shallow marine carbonates in the Mediterranean region using orbitally tuned chemostratigraphy and lithostratigraphy

NASA Astrophysics Data System (ADS)

Auer, Gerald; Piller, Werner E.; Reuter, Markus; Harzhauser, Mathias

2015-04-01

During the Miocene prominent oxygen isotope events (Mi-events) reflect major changes in glaciation, while carbonate isotope maxima (CM-events) reflect changes in organic carbon burial, particularly during the Monterey carbon isotope excursion. However, despite their importance to the global climate history they have never been recorded in shallow marine carbonate successions. The Decontra section on the Maiella Platform (central Apennines, Italy), however, allows to resolve them for the first time in such a setting during the early to middle Miocene. The present study improves the stratigraphic resolution of parts of the Decontra section via orbital tuning of high-resolution gamma ray (GR) and magnetic susceptibility data to the 405 kyr eccentricity metronome. The tuning allows, within the established biostratigraphic, sequence stratigraphic, and isotope stratigraphic frameworks, a precise correlation of the Decontra section with pelagic records of the Mediterranean region, as well as the global paleoclimatic record and the global sea level curve. Spectral series analyses of GR data further indicate that the 405 kyr orbital cycle is particularly well preserved during the Monterey Event. Since GR is a direct proxy for authigenic uranium precipitation during increased burial of organic carbon in the Decontra section, it follows the same long-term orbital pacing as observed in the carbon isotope records. The 405 kyr GR beat is thus correlated with the carbon isotope maxima observed during the Monterey Event. Finally, the Mi-events can now be recognized in the δ18O record and coincide with plankton-rich, siliceous, or phosphatic horizons in the lithology of the section.

Diagrams for comprehensive molecular orbital-based chemical reaction analyses: reactive orbital energy diagrams.

PubMed

Tsuneda, Takao; Singh, Raman Kumar; Chattaraj, Pratim Kumar

2018-05-15

Reactive orbital energy diagrams are presented as a tool for comprehensively performing orbital-based reaction analyses. The diagrams rest on the reactive orbital energy theory, which is the expansion of conceptual density functional theory (DFT) to an orbital energy-based theory. The orbital energies on the intrinsic reaction coordinates of fundamental reactions are calculated by long-range corrected DFT, which is confirmed to provide accurate orbital energies of small molecules, combining with a van der Waals (vdW) correlation functional, in order to examine the vdW effect on the orbital energies. By analysing the reactions based on the reactive orbital energy theory using these accurate orbital energies, it is found that vdW interactions significantly affect the orbital energies in the initial reaction processes and that more than 70% of reactions are determined to be initially driven by charge transfer, while the remaining structural deformation (dynamics)-driven reactions are classified into identity, cyclization and ring-opening, unimolecular dissociation, and H2 reactions. The reactive orbital energy diagrams, which are constructed using these results, reveal that reactions progress so as to delocalize the occupied reactive orbitals, which are determined as contributing orbitals and are usually not HOMOs, by hybridizing the unoccupied reactive orbitals, which are usually not LUMOs. These diagrams also raise questions about conventional orbital-based diagrams such as frontier molecular orbital diagrams, even for the well-established interpretation of Diels-Alder reactions.

Seismoball: A Small Europa Orbiter Drop-Off Probe for Early Exploration of the Europan Surface

NASA Technical Reports Server (NTRS)

Tamppari, L.; Zimmerman, W.; Green, J.

2001-01-01

Recent magnetometry data received from Galileo indicate that the most likely explanation for the magnetic signature there is indeed a global conducting layer below the surface. This conducting layer is well matched by a salty, mineral rich strata beneath the Europan ice crust or a salt water ocean. Galileo imaging results show a variety of terrain types thought to contain young material; for example, lineaments, chaotic terrain, and eruption features. Additionally, Galileo images have shown indications of areas of up-welling where subsurface material periodically gets pushed to the surface due to the forces of fracturing, butting, and refreezing of the ice sheet. While Europa Orbiter will provide close-flyby high resolution images, as well as magnetometry, spectroscopy and other remote sensing data of the surface, it will not be able to provide essential engineering data like surface hardness and surface ice structure needed to support eventual landed missions. Additionally, ice chemical composition at microscopic scales can only be studied in detail through in situ instrumentation. Seismoball is a small probe designed to be injected into a surface intersect orbit around Europa. Using small reverse thrusters, the probe will be capable of nulling the high horizontal injection velocity as it approaches the 2 km surface injection altitude, thus allowing it to fall to the surface at an impact velocity of < 100m/sec (much less than the DS-2 impact velocities). The external breakaway thruster structure and crushable exterior shell absorb the impact energy while allowing the science instrument suite to remain intact. JPL has already started analyzing the entry dynamics and designing/building a small, low mass probe which will withstand the impact g-forces and fit as a 'carry-on' on board the Europa Orbiter. The probe will carry a suite of 5-6 micro-instruments for imaging the surface (both microscopic and far-field), surface and shallow subsurface ice temperatures

Early Program Development

NASA Image and Video Library

1969-01-01

As part of the Space Task Group's recommendations for more commonality and integration in America's space program, Marshall Space Flight Center engineers proposed an orbiting propellant storage facility to augment Space Shuttle missions. In this artist's concept from 1969 an early version of the Space Shuttle is shown refueling at the facility.

Integrated orbital servicing study follow-on. Volume 2: Technical analysis and system design

NASA Technical Reports Server (NTRS)

1978-01-01

In-orbit service functional and physical requirements to support both low and high Earth orbit servicing/maintenance operations were defined, an optimum servicing system configuration was developed and mockups and early prototype hardware were fabricated to demonstrate and validate the concepts selected. Significant issues addressed include criteria for concept selection; representative mission equipment and approaches to their design for serviceability; significant serviceable spacecraft design aspects; servicer mechanism operation in one-g; approaches for the demonstration/simulation; and service mechanism structure design approach.

Outward Migration of Giant Planets in Orbital Resonance

NASA Astrophysics Data System (ADS)

D'Angelo, G.; Marzari, F.

2013-05-01

A pair of giant planets interacting with a gaseous disk may be subject to convergent orbital migration and become locked into a mean motion resonance. If the orbits are close enough, the tidal gaps produced by the planets in the disk may overlap. This represents a necessary condition to activate the outward migration of the pair. However, a number of other conditions must also be realized in order for this mechanism to operate. We have studied how disk properties, such as turbulence viscosity, temperature, surface density gradient, mass, and age, may affect the outcome of the outward migration process. We have also investigated the implications on this mechanism of the planets' gas accretion. If the pair resembles Jupiter and Saturn, the 3:2 orbital resonance may drive them outward until they reach stalling radii for migration, which are within ~10 AU of the star for disks representative of the early proto-solar nebula. However, planet post-formation conditions in the disk indicate that such planets become typically locked in the 1:2 orbital resonance, which does not lead to outward migration. Planet growth via gas accretion tends to alter the planets' mass-ratio and/or the disk accretion rate toward the star, reducing or inhibiting outward migration. Support from NASA Outer Planets Research Program and NASA Origins of Solar Systems Program is gratefully acknowledged.

100 Myr record of sequences, sedimentary facies and sea level change from Ocean Drilling Program onshore coreholes, US Mid-Atlantic coastal plain

USGS Publications Warehouse

Browning, J.V.; Miller, K.G.; Sugarman, P.J.; Kominz, M.A.; McLaughlin, P.P.; Kulpecz, A.A.; Feigenson, M.D.

2008-01-01

We analyzed the latest Early Cretaceous to Miocene sections (???110-7Ma) in 11 New Jersey and Delaware onshore coreholes (Ocean Drilling Program Legs 150X and 174AX). Fifteen to seventeen Late Cretaceous and 39-40 Cenozoic sequence boundaries were identified on the basis of physical and temporal breaks. Within-sequence changes follow predictable patterns with thin transgressive and thick regressive highstand systems tracts. The few lowstands encountered provide critical constraints on the range of sea-level fall. We estimated paleowater depths by integrating lithofacies and biofacies analyses and determined ages using integrated biostratigraphy and strontium isotopic stratigraphy. These datasets were backstripped to provide a sea-level estimate for the past ???100 Myr. Large river systems affected New Jersey during the Cretaceous and latest Oligocene-Miocene. Facies evolved through eight depositional phases controlled by changes in accommodation, long-term sea level, and sediment supply: (1) the Barremian-earliest Cenomanian consisted of anastomosing riverine environments associated with warm climates, high sediment supply, and high accommodation; (2) the Cenomanian-early Turonian was dominated by marine sediments with minor deltaic influence associated with long-term (107 year) sea-level rise; (3) the late Turonian through Coniacian was dominated by alluvial and delta plain systems associated with long-term sea-level fall; (4) the Santonian-Campanian consisted of marine deposition under the influence of a wave-dominated delta associated with a long-term sea-level rise and increased sediment supply; (5) Maastrichtian-Eocene deposition consisted primarily of starved siliciclastic, carbonate ramp shelf environments associated with very high long-term sea level and low sediment supply; (6) the late Eocene-Oligocene was a starved siliciclastic shelf associated with moderately high sea-level and low sediment supply; (7) late early-middle Miocene consisted of a

Titanium Mesh Reconstruction of Orbital Roof Fracture with Traumatic Encephalocele: A Case Report and Review of Literature

PubMed Central

Mokal, Nitin J.; Desai, Mahinoor F.

2012-01-01

Orbital roof fractures are rare. Traumatic encephaloceles in the orbital cavity are even rarer, with only 21 cases published to date. Orbital roof fractures are generally encountered in males between 20 and 40 years of age following automobile collision. We report a case of an orbital roof fracture with traumatic encephalocele into the left orbit. Early diagnosis and treatment are very important because the raised intraorbital pressure may irreversibly damage the optic nerve. Computed tomography with 3-D reconstruction, the imaging modality of choice, showed the displaced fracture fragment deep into the orbit. Reconstruction of the orbital roof should be performed in every case. We used an extracranial approach to elevate the fracture with titanium mesh to stabilize the fragment. The cosmetic results were excellent but delay in treatment was responsible for delayed recovery of vision. The case report is followed by a brief overview of orbital roof fractures including pertinent review of literature. PMID:23450105

Space Shuttle Orbiter Drag Chute Summary

NASA Technical Reports Server (NTRS)

Lowry, Charles H.

2013-01-01

This paper summarizes the development history and technical highlights of the Space Shuttle Orbiter Drag Chute Program. Data and references are given on the design, development, and testing of the system, plus several interesting operational issues and solutions. The last Shuttle flight was completed in 2011 and all the Orbiters have now become museum pieces. Before all the data from system development and the 86 Orbiter Drag Chute (ODC) operational landings is lost or forgotten, it may be useful to summarize it here and to identify data sources for future reference. Much has been written about various aspects of the program, and this summary has attempted to cite many such references to make available more detailed information. The ODC program was a high-visibility NASA program that afforded the opportunity to thoroughly engineer and test the chute system, far beyond so many of today s tight-budget programs. So the ODC program was extremely informative--it provided a wide scope of information including protective door jettison issues and solutions, wind tunnel data and analyses on chute stability and drag behind a huge and rather blunt forebody, component and system reuse, and chute cleaning methods. Technology and data created have aided several current and past parachute programs, and will continue to do so in the future. The original Orbiter preliminary design included a drag parachute-- it was deleted early to save weight. But after the 1987 Challenger accident and during the program redefinition phase that followed, Astronaut John Young presented a strong case for enhancing landing safety by adding nosegear steering, brake improvements, and reviving the drag chute.

Jupiter Europa Orbiter Architecture Definition Process

NASA Technical Reports Server (NTRS)

Rasmussen, Robert; Shishko, Robert

2011-01-01

The proposed Jupiter Europa Orbiter mission, planned for launch in 2020, is using a new architectural process and framework tool to drive its model-based systems engineering effort. The process focuses on getting the architecture right before writing requirements and developing a point design. A new architecture framework tool provides for the structured entry and retrieval of architecture artifacts based on an emerging architecture meta-model. This paper describes the relationships among these artifacts and how they are used in the systems engineering effort. Some early lessons learned are discussed.

The Results of Complex Research of GSS "SBIRS-Geo 2" Behavior in the Orbit

NASA Astrophysics Data System (ADS)

Sukhov, P. P.; Epishev, V. P.; Sukhov, K. P.; Karpenko, G. F.; Motrunich, I. I.

2017-04-01

The new generation of geosynchronous satellites SBIRS of US Air Force early warning system series (Satellite Early Warning System) replaced the previous DSP-satellite series (Defense Support Program). Currently from the territory of Ukraine, several GSS of DSP series and one "SBIRS-Geo 2" are available to observation. During two years of observations, we have received and analyzed for two satellites more than 30 light curves in B, V, R photometric system. As a result of complex research, we propose a model of "SBIRS-Geo" 2 orbital behavior compared with the same one of the DSP-satellite. To control the entire surface of the Earth with 15-16 sec interval, including the polar regions, 4 SBIRS satellites located every 90 deg. along the equator are enough in GEO orbit. Since DSP-satellites provide the coverage of the Earth's surface to 83 deg. latitudes with a period of 50 sec, DSP-satellites should be 8. All the conclusions were made based on an analysis of photometric and coordinate observations using the simulation of the dynamics of their orbital behavior.

Study of an orbiting tethered dumbbell system having positive orbital energy

NASA Technical Reports Server (NTRS)

Arnold, David A.

1988-01-01

For very long tethered systems the sum of the kinetic and potential energy can be positive. The system remains in a circular orbit as long as the masses remain vertically aligned. The system is unstable without constant control of the alignment. If the upper mass rotates forward in the direction of the orbital motion, the system escapes out of orbit. If the upper mass rotates backward, the system falls out of orbit and the lower mass impacts the body around which the system is orbiting.

The orbital record in stratigraphy

NASA Technical Reports Server (NTRS)

Fischer, Alfred G.

1992-01-01

Orbital signals are being discovered in pre-Pleistocene sediments. Due to their hierarchical nature these cycle patterns are complex, and the imprecision of geochronology generally makes the assignment of stratigraphic cycles to specific orbital cycles uncertain, but in sequences such as the limnic Newark Group under study by Olsen and pelagic Cretaceous sequence worked on by our Italo-American group the relative frequencies yield a definitive match to the Milankovitch hierarchy. Due to the multiple ways in which climate impinges on depositional systems, the orbital signals are recorded in a multiplicity of parameters, and affect different sedimentary facies in different ways. In platform carbonates, for example, the chief effect is via sea-level variations (possibly tied to fluctuating ice volume), resulting in cycles of emergence and submergence. In limnic systems it finds its most dramatic expression in alternations of lake and playa conditions. Biogenic pelagic oozes such as chalks and the limestones derived from them display variations in the carbonate supplied by planktonic organisms such as coccolithophores and foraminifera, and also record variations in the aeration of bottom waters. Whereas early studies of stratigraphic cyclicity relied mainly on bedding variations visible in the field, present studies are supplementing these with instrumental scans of geochemical, paleontological, and geophysical parameters which yield quantitative curves amenable to time-series analysis; such analysis is, however, limited by problems of distorted time-scales. My own work has been largely concentrated on pelagic systems. In these, the sensitivity of pelagic organisms to climatic-oceanic changes, combined with the sensitivity of botton life to changes in oxygen availability (commonly much more restricted in the Past than now) has left cyclic patterns related to orbital forcing. These systems are further attractive because (1) they tend to offer depositional continuity

The Campanian Ignimbrite Eruption: New Data on Volcanic Ash Dispersal and Its Potential Impact on Human Evolution

PubMed Central

Fitzsimmons, Kathryn E.; Hambach, Ulrich; Veres, Daniel; Iovita, Radu

2013-01-01

The Campanian Ignimbrite (CI) volcanic eruption was the most explosive in Europe in the last 200,000 years. The event coincided with the onset of an extremely cold climatic phase known as Heinrich Event 4 (HE4) approximately 40,000 years ago. Their combined effect may have exacerbated the severity of the climate through positive feedbacks across Europe and possibly globally. The CI event is of particular interest not only to investigate the role of volcanism on climate forcing and palaeoenvironments, but also because its timing coincides with the arrival into Europe of anatomically modern humans, the demise of Neanderthals, and an associated major shift in lithic technology. At this stage, however, the degree of interaction between these factors is poorly known, based on fragmentary and widely dispersed data points. In this study we provide important new data from Eastern Europe which indicate that the magnitude of the CI eruption and impact of associated distal ash (tephra) deposits may have been substantially greater than existing models suggest. The scale of the eruption is modelled by tephra distribution and thickness, supported by local data points. CI ashfall extends as far as the Russian Plain, Eastern Mediterranean and northern Africa. However, modelling input is limited by very few data points in Eastern Europe. Here we investigate an unexpectedly thick CI tephra deposit in the southeast Romanian loess steppe, positively identified using geochemical and geochronological analyses. We establish the tephra as a widespread primary deposit, which blanketed the topography both thickly and rapidly, with potentially catastrophic impacts on local ecosystems. Our discovery not only highlights the need to reassess models for the magnitude of the eruption and its role in climatic transition, but also suggests that it may have substantially influenced hominin population and subsistence dynamics in a region strategic for human migration into Europe. PMID:23799050

The Campanian Ignimbrite eruption: new data on volcanic ash dispersal and its potential impact on human evolution.

PubMed

Fitzsimmons, Kathryn E; Hambach, Ulrich; Veres, Daniel; Iovita, Radu

2013-01-01

The Campanian Ignimbrite (CI) volcanic eruption was the most explosive in Europe in the last 200,000 years. The event coincided with the onset of an extremely cold climatic phase known as Heinrich Event 4 (HE4) approximately 40,000 years ago. Their combined effect may have exacerbated the severity of the climate through positive feedbacks across Europe and possibly globally. The CI event is of particular interest not only to investigate the role of volcanism on climate forcing and palaeoenvironments, but also because its timing coincides with the arrival into Europe of anatomically modern humans, the demise of Neanderthals, and an associated major shift in lithic technology. At this stage, however, the degree of interaction between these factors is poorly known, based on fragmentary and widely dispersed data points. In this study we provide important new data from Eastern Europe which indicate that the magnitude of the CI eruption and impact of associated distal ash (tephra) deposits may have been substantially greater than existing models suggest. The scale of the eruption is modelled by tephra distribution and thickness, supported by local data points. CI ashfall extends as far as the Russian Plain, Eastern Mediterranean and northern Africa. However, modelling input is limited by very few data points in Eastern Europe. Here we investigate an unexpectedly thick CI tephra deposit in the southeast Romanian loess steppe, positively identified using geochemical and geochronological analyses. We establish the tephra as a widespread primary deposit, which blanketed the topography both thickly and rapidly, with potentially catastrophic impacts on local ecosystems. Our discovery not only highlights the need to reassess models for the magnitude of the eruption and its role in climatic transition, but also suggests that it may have substantially influenced hominin population and subsistence dynamics in a region strategic for human migration into Europe.

A technician works on the Mars Climate Orbiter in SAEF-2

NASA Technical Reports Server (NTRS)

1998-01-01

In the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2), a technician works on the Mars Climate Orbiter which is scheduled to launch on Dec. 10, 1998, aboard a Boeing Delta II rocket. The Mars Climate Orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (two Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface.

Unexpected climatic impacts of orbital forcing out of the Quaternary

NASA Astrophysics Data System (ADS)

Ramstein, G.; Zhang, Z.; Le Hir, G.; Contoux, C.; Donnadieu, Y.; Dumas, C.; Schuster, M.; Li, C.

2016-12-01

For Quaternary, the impact of orbital variations on climate is huge and well documented. Especially, during the last million years, drastic climate changes occurred, consisting in transitions from glacial to interglacial periods driven by changes in 65°N summer insolation with 100 kyrs periodicity. Nevertheless, the imprint of so-called Milankovic forcings has also been found for Tertiary and Secondary. For both periods, the climatic imprints of orbital forcings are recorded in a warm world without ice sheet. Here, we show through simulation studies the large impact of orbital forcing in very different geological contexts. The first and most striking result depicts the role of insolation changes during the melting of the Marinoan snowball [635 Ma] (Benn et al, Nature Geoscience 2015). This is one of the oldest imprints of orbital forcing on climate. Our result solved a long lasting controversy concerning the melting of the last snowball episode between a huge deglaciation at very high CO2 level and data showing glacial/interglacial cycles occurring during that melting. Our modelling studies focusing on Svalbard high resolution records demonstrate that the glacial/fluvial oscillation was related to orbital forcing in a context of very high CO2 level. Much more recently, during the Tortonian period [11-7 Ma], the orbital cycles shaped the environment and drove the hominin dispersal in Africa. During Tortonian, the ultimate shrinkage of a huge epicontinental sea, that extended from Eastern Europe to Western Asia, has been shown to produce major changes on Asian monsoon (Ramstein et al, Nature, 1997) and triggered the onset of Sahara desert (Zhang et al, Nature 2014). Moreover, this shrinkage drastically enhanced the climate response to orbital changes at the emergence of early hominins in North Africa. Through these two illustrations,we pointed out very different climatic impacts of orbital forcing out of Quaternary.

Sentinel-2A: Orbit Modelling Improvements and their Impact on the Orbit Prediction

NASA Astrophysics Data System (ADS)

Peter, Heike; Otten, Michiel; Fernández Sánchez, Jaime; Fernández Martín, Carlos; Féménias, Pierre

2016-07-01

Sentinel-2A is the second satellite of the European Copernicus Programme. The satellite has been launched on 23rd June 2015 and it is operational since mid October 2015. This optical mission carries a GPS receiver for precise orbit determination. The Copernicus POD (Precise Orbit Determination) Service is in charge of generating precise orbital products and auxiliary files for Sentinel-2A as well as for the Sentinel-1 and -3 missions. The accuracy requirements for the Sentinel-2A orbit products are not very stringent with 3 m in 3D (3 sigma) for the near real-time (NRT) orbit and 10 m in 2D (3 sigma) for the predicted orbit. The fulfilment of the orbit accuracy requirements is normally not an issue. The Copernicus POD Service aims, however, to provide the best possible orbits for all three Sentinel missions. Therefore, a sophisticated box-wing model is generated for the Sentinel-2 satellite as it is done for the other two missions as well. Additionally, the solar wing of the satellite is rewound during eclipse, which has to be modelled accordingly. The quality of the orbit prediction is dependent on the results of the orbit estimation performed before it. The values of the last estimation of each parameter is taken for the orbit propagation, i.e. estimating ten atmospheric drag coefficients per 24h, the value of the last coefficient is used as a fix parameter for the subsequent orbit prediction. The question is whether the prediction might be stabilised by, e.g. using an average value of all ten coefficients. This paper presents the status and the quality of the Sentinel-2 orbit determination in the operational environment of the Copernicus POD Service. The impact of the orbit model improvements on the NRT and predicted orbits is studied in detail. Changes in the orbit parametrization as well as in the settings for the orbit propagation are investigated. In addition, the impact of the quality of the input GPS orbit and clock product on the Sentinel-2A orbit

The challenge of assembling a space station in orbit

NASA Technical Reports Server (NTRS)

Brand, Vance D.

1990-01-01

Assembly of a space station in orbit is a challenging and complicated task. If mankind is to exploit the knowledge already gained from space flight and continue to advance the frontiers of space exploration, then space stations in orbit must be part of the overall space infrastructure. Space stations, like the Freedom, having relatively large mass which greatly exceeds the lifting capability of their transportation system, are candidates for on-orbit assembly. However, when a large wide-body booster is available, there are significant advantages to having a deployable space station assembled on Earth and transported into orbit intact or in a few large pieces. The United States will build the Space Station Freedom by the assembly method. Freedom's assembly is feasible, but a significant challenge, and it will absorb much of NASA's effort in the next 8 years. The Space Station Freedom is an international program which will be the centerpiece of the free world's space activities in the late 1990's. Scientific information and products from the Space Station Freedom and its use as a transportation depot will advance technology and facilitate the anticipated manned space exploration surge to the Moon and Mars early in the 21st century.

View of the early morning launch of STS 41-G Challenger

NASA Image and Video Library

1984-10-05

View of the early morning launch of STS 41-G Challenger. The dark launch complex is illuminated by spotlights as the orbiter begins its ascent from the pad. The light is reflected off the clouds of smoke from the orbiter's engines.

A new species of Cretalamna sensu stricto (Lamniformes, Otodontidae) from the Late Cretaceous (Santonian-Campanian) of Alabama, USA

PubMed Central

Ehret, Dana J.

2018-01-01

Decades of collecting from exposures of the Upper Cretaceous Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk in Alabama, USA has produced large numbers of isolated Cretalamna (sensu stricto) teeth. Many of these teeth had formerly been assigned to the extinct Late Cretaceous shark Cretalamna appendiculata (Agassiz, 1843), a taxon that is now considered largely restricted to the Turonian of Europe. Recent studies have shed light on the diversity of Late Cretaceous Cretalamna (s.s.) taxa, and here we recognize a new species from Alabama, Cretalamna bryanti. The teeth of C. bryanti sp. nov. appear aligned with the members of the Cretalamna borealis species group, but can be distinguished from these other species by a combination of the following: anterior teeth with a more pronounced and triangular lingual root protuberance, broader triangular cusp, and a taller root relative to the height of the crown; anteriorly situated lateroposterior teeth have a distally inclined or hooked main cusp and more than one pair of lateral cusplets; and lateroposterior teeth have a strong distally hooked main cusp and a root that is largely symmetrical in basal view. At present, C. bryanti sp. nov. is stratigraphically confined to the Santonian/Campanian Dicarinella asymetrica Sigal, 1952 and Globotruncanita elevata Brotzen, 1934 Planktonic Foraminiferal Zones within the Tombigbee Sand Member of the Eutaw Formation and Mooreville Chalk, and teeth have been collected from only four counties in central and western Alabama. The recognition of C. bryanti sp. nov. in Alabama adds to our knowledge on the diversity and distribution of Late Cretaceous otodontids in the region. PMID:29333348

Technology requirements for future Earth-to-geosynchronous orbit transportation systems. Volume 2: Technical results

NASA Technical Reports Server (NTRS)

Caluori, V. A.

1980-01-01

Technologies either critical to performance of offering cost advantages compared to the investment required to bring them to usable confidence levels are identified. A total transportation system is used as an evaluation yardstick. Vehicles included in the system are a single stage to orbit launch vehicle used in a priority cargo role, a matching orbit transfer vehicle, a heavy lift launch vehicle with a low Earth orbit delivery capability of 226, 575 kg, and a matching solar electric cargo orbit transfer vehicle. The system and its reference technology level are consistent with an initial operational capability in 1990. The 15 year mission scenario is based on early space industrialization leading to the deployment of large systems such as power satellites. Life cycle cost benefits in discounted and undiscounted dollars for each vehicle, technology advancement, and the integrated transportation system are calculated. A preliminary functional analysis was made of the operational support requirements for ground based and space based chemical propulsion orbit transfer vehicles.

Spin-orbit-torque-induced skyrmion dynamics for different types of spin-orbit coupling

NASA Astrophysics Data System (ADS)

Lee, Seung-Jae; Kim, Kyoung-Whan; Lee, Hyun-Woo; Lee, Kyung-Jin

2018-06-01

We investigate current-induced skyrmion dynamics in the presence of Dzyaloshinskii-Moriya interaction and spin-orbit spin-transfer torque corresponding to various types of spin-orbit coupling. We determine the symmetries of Dzyaloshinskii-Moriya interaction and spin-orbit spin-transfer torque based on linear spin-orbit coupling model. We find that like interfacial Dzyaloshinskii-Moriya interaction (Rashba spin-orbit coupling) and bulk Dzyaloshinskii-Moriya interaction (Weyl spin-orbit coupling), Dresselhaus spin-orbit coupling also has a possibility for stabilizing skyrmion and current-induced skyrmion dynamics.

A Case of Orbital Abscess following Porous Orbital Implant Infection

PubMed Central

Hong, Seung Woo; Paik, Ji-Sun; Kim, So-Youl

2006-01-01

Purpose We present a case of orbital abscess following porous orbital implant infection in a 73-year-old woman with rheumatoid arthritis. Methods Just one month after a seemingly uncomplicated enucleation and porous polyethylene (Medpor®) orbital implant surgery, implant exposure developed with profuse pus discharge. The patient was unresponsive to implant removal and MRI confirmed the presence of an orbital pus pocket. Despite extirpation of the four rectus muscles, inflammatory granulation debridement and abscess drainage, another new pus pocket developed. Results After partial orbital exenteration, the wound finally healed well without any additional abscess formation. Conclusions A patient who has risk factors for delayed wound healing must be examined thoroughly and extreme care such as exenteration must be taken if there is persistent infection. PMID:17302210

Impact of tidal density variability on orbital and reentry predictions

NASA Astrophysics Data System (ADS)

Leonard, J. M.; Forbes, J. M.; Born, G. H.

2012-12-01

Since the first satellites entered Earth orbit in the late 1950's and early 1960's, the influences of solar and geomagnetic variability on the satellite drag environment have been studied, and parameterized in empirical density models with increasing sophistication. However, only within the past 5 years has the realization emerged that "troposphere weather" contributes significantly to the "space weather" of the thermosphere, especially during solar minimum conditions. Much of the attendant variability is attributable to upward-propagating solar tides excited by latent heating due to deep tropical convection, and solar radiation absorption primarily by water vapor and ozone in the stratosphere and mesosphere, respectively. We know that this tidal spectrum significantly modifies the orbital (>200 km) and reentry (60-150 km) drag environments, and that these tidal components induce longitude variability not yet emulated in empirical density models. Yet, current requirements for improvements in orbital prediction make clear that further refinements to density models are needed. In this paper, the operational consequences of longitude-dependent tides are quantitatively assessed through a series of orbital and reentry predictions. We find that in-track prediction differences incurred by tidal effects are typically of order 200 ± 100 m for satellites in 400-km circular orbits and 15 ± 10 km for satellites in 200-km circular orbits for a 24-hour prediction. For an initial 200-km circular orbit, surface impact differences of order 15° ± 15° latitude are incurred. For operational problems with similar accuracy needs, a density model that includes a climatological representation of longitude-dependent tides should significantly reduce errors due to this source.

Mars NanoOrbiter: A CubeSat for Mars System Science

NASA Astrophysics Data System (ADS)

Ehlmann, Bethany; Klesh, Andrew; Alsedairy, Talal

2017-10-01

The Mars NanoOrbiter mission consists of two identical 12U spacecraft, launched simultaneously as secondary payloads on a larger planetary mission launch, and deployed to Earth-escape, as early as with Mars 2020. The nominal mission will last for 1 year, during which time the craft will independently navigate to Mars, enter into elliptical orbit, and achieve close flybys of Phobos and Deimos, obtaining unprecedented coverage of each moon. The craft will additionally provide high temporal resolution data of Mars clouds and atmospheric phenomena at multiple times of day. Two spacecraft provide redundancy to reduce the risk in meeting the science objectives at the Mars moons and enhanced coverage of the dynamic Mars atmosphere. This technology is enabled by recent advances in CubeSat propulsion technology, attitude control systems, guidance, navigation and control. NanoOrbiter builds directly on the systems heritage of the MarCO mission, scheduled to launch with the 2018 Discovery mission Insight.

Sleep and circadian rhythms in four orbiting astronauts.

PubMed

Monk, T H; Buysse, D J; Billy, B D; Kennedy, K S; Willrich, L M

1998-06-01

This experiment measured the sleep and circadian rhythms of four male astronauts aboard a space shuttle (STS-78) orbiting the Earth for 17 days. The space mission was specially scheduled to minimize disruptions in circadian rhythms and sleep so that the effects of space flight and microgravity per se could be studied. Data were collected in 72-h measurement blocks: one block 7 days before launch, one early within the mission (3 days after launch), one late in the mission (12 days after launch), and one 18 days after landing. Within each measurement block, all sleep was recorded both polysomnographically and by sleep diary. Core body temperature was sampled every 6 mins. Actillumes were worn continuously. All urine samples were collected separately. Performance was assessed by a computerized test battery (3/day) and by end-of-shift questionnaires (1/day); mood and alertness were measured by visual analogue scales (5/day). Circadian rhythms in orbit appeared to be very similar in phase and amplitude to those on the ground, and were appropriately aligned for the required work/rest schedule. There was no change from early flight to late flight. This was also reflected in mood, alertness, and performance scores, which were satisfactory at both in-flight time points. However, in-flight sleep showed a decreased amount of sleep obtained (mean = 6.1 h), and all four astronauts showed a decrease in delta sleep. No further degradation in sleep was seen when early flight was compared to late flight, and no other sleep parameters showed reliable trends.

Review of Orbiter Flight Boundary Layer Transition Data

NASA Technical Reports Server (NTRS)

Mcginley, Catherine B.; Berry, Scott A.; Kinder, Gerald R.; Barnell, maria; Wang, Kuo C.; Kirk, Benjamin S.

2006-01-01

In support of the Shuttle Return to Flight program, a tool was developed to predict when boundary layer transition would occur on the lower surface of the orbiter during reentry due to the presence of protuberances and cavities in the thermal protection system. This predictive tool was developed based on extensive wind tunnel tests conducted after the loss of the Space Shuttle Columbia. Recognizing that wind tunnels cannot simulate the exact conditions an orbiter encounters as it re-enters the atmosphere, a preliminary attempt was made to use the documented flight related damage and the orbiter transition times, as deduced from flight instrumentation, to calibrate the predictive tool. After flight STS-114, the Boundary Layer Transition Team decided that a more in-depth analysis of the historical flight data was needed to better determine the root causes of the occasional early transition times of some of the past shuttle flights. In this paper we discuss our methodology for the analysis, the various sources of shuttle damage information, the analysis of the flight thermocouple data, and how the results compare to the Boundary Layer Transition prediction tool designed for Return to Flight.

Preoperative diagnosis of orbital cavernous hemangioma: a 99mTc-RBC SPECT study.

PubMed

Burroni, Luca; Borsari, Giulia; Pichierri, Patrizia; Polito, Ennio; Toscano, Olga; Grassetto, Gaia; Al-Nahhas, Adil; Rubello, Domenico; Vattimo, Angelo Giuseppe

2012-11-01

This study aimed to describe 99mTc-labeled RBC scintigraphy as a diagnostic method for orbital cavernous hemangiomas and to evaluate this diagnostic tool according to surgical outcomes. Fifty-five patients with clinical and radiological (US, CT, and/or MRI) suspicion of unilateral cavernous hemangioma of the orbit underwent 99mTc-RBC SPECT study.Qualitative and semiquantitative evaluations were performed, and results were statistically analyzed. SPECT images showed focal uptake in the orbital mass in 36 of 55 patients. Nineteen patients had a negative scintigraphic pattern, with concordance of early and late absence of uptake of 99mTc-RBC.Our procedure showed 100% sensitivity and 88.9% specificity for the diagnosis of orbital cavernous hemangioma, with a positive predictive value of 90.9% and a negative predictive value of 100%. 99mTc-RBC imaging is safe, easy to perform, and highly accurate in providing adequate clinical and surgical management. As a noninvasive and highly specific method for diagnosing orbital hemangioma, 99mTc-RBC scintigraphy can avoid more invasive imaging or biopsy.

Orbital and Ventromedial Prefrontal Cortex Functioning in Parkinson's Disease: Neuropsychological Evidence

ERIC Educational Resources Information Center

Poletti, Michele; Bonuccelli, Ubaldo

2012-01-01

A recent paper (Zald & Andreotti, 2010) reviewed neuropsychological tasks that assess the function of the orbital and ventromedial portions of the prefrontal cortex (OMPFC). Neuropathological studies have shown that the function of the OMPFC should be preserved in the early stages of Parkinson's disease (PD) but becomes affected in the advanced…

Combined orbits and clocks from the IGS 2nd reprocessing

NASA Astrophysics Data System (ADS)

Griffiths, J.; Ray, J.

2016-12-01

In early 2015, the Analysis Centers (ACs) of the International GNSS Service (IGS) completed their second reanalysis of the full history of globally distributed GPS and GLONASS data collected since 1994. The suite of reprocessed AC solutions includes daily product files containing station positions, Earth rotation parameters, satellite orbits and clocks. This second reprocessing—or repro2—provided the IGS contribution to ITRF2014; it follows the successful first reprocessing, which provided the IGS input for ITRF2008. For this poster, we will discuss the newly combined repro2 GPS orbits and clocks. We also revisit our previous analysis of orbit day-boundary discontinuities with several significant changes and improvements: 1) Orbit discontinuities for the contributing ACs were studied in addition to those for the IGS repro2 combined orbits. (2) Apart from homogeneous reprocessing with updated analysis models, the main difference compared to the IGS Final operational products is that NOAA/NGS inputs were not submitted for the IGS reprocessing, yet they contribute heavily in the operational orbits in recent years. (3) Also, during spring 2016, the ESA modified their orbit model so that it is no longer consistent with the one used for reprocessing. A much longer span of orbits was available now, up to 11.2 years for some individual satellites, which allows a far better resolution of spectral features. 4) The procedure to compute orbit discontinuities has been further refined to account for extrapolation edge effects, improved geopotential fields, and to allow for spectral analysis of a longer time series of jumps. The satellite position time series used are complete enough that linear interpolation is necessary for only sparse gaps. So the key results are based on standard FFT power spectra (stacked over the available constellation and lightly smoothed). However, we have also computed Lomb-Scargle periodgrams to provide higher frequency resolution of some spectral

Post-traumatic orbital reconstruction: anatomical landmarks and the concept of the deep orbit.

PubMed

Evans, B T; Webb, A A C

2007-04-01

Dissection deep within the orbit is a cause for concern to surgeons because of the perceived risks of injuring critical structures such as the contents of the superior orbital fissure and the optic nerve. Although "safe distances" (those distances within which it is considered safe to dissect within the orbit) have been described, these are of limited value if the orbit is severely disrupted or is congenitally shallow. In addition, traumatic defects in the orbital floor, in particular, often extend beyond these distances. Reliable landmarks based on the relations between anatomical structures within the orbit, rather than absolute distances, are described that permit safe dissection within the orbit. We present the concept of the deep orbit and describe its relevance to repair of injuries.

Independent Orbiter Assessment (IOA): Analysis of the orbital maneuvering system

NASA Technical Reports Server (NTRS)

Prust, C. D.; Paul, D. J.; Burkemper, V. J.

1987-01-01

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results for the Orbital Maneuvering System (OMS) hardware are documented. The OMS provides the thrust to perform orbit insertion, orbit circularization, orbit transfer, rendezvous, and deorbit. The OMS is housed in two independent pods located one on each side of the tail and consists of the following subsystems: Helium Pressurization; Propellant Storage and Distribution; Orbital Maneuvering Engine; and Electrical Power Distribution and Control. The IOA analysis process utilized available OMS hardware drawings and schematics for defining hardware assemblies, components, and hardware items. Each level of hardware was evaluted and analyzed for possible failure modes and effects. Criticality was asigned based upon the severity of the effect for each failure mode.

Orbital endoscopic surgery

PubMed Central

Selva, Dinesh

2008-01-01

Minimally invasive ″keyhole″ surgery performed using endoscopic visualization is increasing in popularity and is being used by almost all surgical subspecialties. Within ophthalmology, however, endoscopic surgery is not commonly performed and there is little literature on the use of the endoscope in orbital surgery. Transorbital use of the endoscope can greatly aid in visualizing orbital roof lesions and minimizing the need for bone removal. The endoscope is also useful during decompression procedures and as a teaching aid to train orbital surgeons. In this article, we review the history of endoscopic orbital surgery and provide an overview of the technique and describe situations where the endoscope can act as a useful adjunct to orbital surgery. PMID:18158397

Orbiting Rainbows Simulation

NASA Image and Video Library

2015-04-22

This simulated image shows how a cloud of glitter in geostationary orbit would be illuminated and controlled by two laser beams. As the cloud orbits Earth, grains scatter the sun's light at different angles like many tiny prisms, similar to how rainbows are produced from light being dispersed by water droplets. That is why the project concept is called "Orbiting Rainbows." The cloud functions like a reflective surface, allowing the exoplanet (displayed in the bottom right) to be imaged. The orbit path is shown in the top right. On the bottom left, Earth's image is seen behind the cloud. To image an exoplanet, the cloud would need to have a diameter of nearly 98 feet (30 meters). This simulation confines the cloud to a 3.3 x 3.3 x 3.3 foot volume (1 x 1 x 1 meter volume) to simplify the computations. The elements of the orbiting telescope are not to scale. Orbiting Rainbows is currently in Phase II development through the NASA Innovative Advanced Concepts (NIAC) Program. It was one of five technology proposals chosen for continued study in 2014. In the current phase, Orbiting Rainbows researchers are conducting small-scale ground experiments to demonstrate how granular materials can be manipulated using lasers and simulations of how the imaging system would behave in orbit. http://photojournal.jpl.nasa.gov/catalog/PIA19318

Orbital Decompression

MedlinePlus

... A Complications of Sinusitis Epistaxis (Nosebleeds) Allergic Rhinitis (Hay Fever) Headaches and Sinus Disease Disorders of Smell & ... DCR) Disclosure Statement Printer Friendly Orbital Decompression John Lee, MD INTRODUCTION Orbital decompression is a surgical procedure ...

The Geology of Haiti: An Annotated Bibliography of Haiti’s Geology, Geography and Earth Science

DTIC Science & Technology

2010-07-01

Yucatan Peninsula. Abstract: The stratigraphy and age of breccia containing Chicxulub impact glass spherules is documented in late Maastrichtian-early...Tertiary; tsunamis; turbidite; turbidity current structures; Upper Cretaceous; West Indies; Yucatan Peninsula. Notes: SP: USGSOP, Non-USGS...Chichancanab, and Coba, Yucatan Peninsula, Bibliography of Haitian Earth Science Army Geospatial Center June 2010 70 Mexico; Lake Peten-Itza, Peten

Close up view of the Orbiter Discovery in the Orbiter ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Close up view of the Orbiter Discovery in the Orbiter Processing Facility at Kennedy Space Center. The view is a detail of the aft, starboard landing gear and a general view of the Thermal Protection System tiles around the landing-gear housing. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Traumatic orbital CSF leak

PubMed Central

Borumandi, Farzad

2013-01-01

Compared to the cerebrospinalfluid (CSF) leak through the nose and ear, the orbital CSF leak is a rare and underreported condition following head trauma. We present the case of a 49-year-old woman with oedematous eyelid swelling and ecchymosis after a seemingly trivial fall onto the right orbit. Apart from the above, she was clinically unremarkable. The CT scan revealed a minimally displaced fracture of the orbital roof with no emphysema or intracranial bleeding. The fractured orbital roof in combination with the oedematous eyelid swelling raised the suspicion for orbital CSF leak. The MRI of the neurocranium demonstrated a small-sized CSF fistula extending from the anterior cranial fossa to the right orbit. The patient was treated conservatively and the lid swelling resolved completely after 5 days. Although rare, orbital CSF leak needs to be included in the differential diagnosis of periorbital swelling following orbital trauma. PMID:24323381

Orbital debris issues

NASA Technical Reports Server (NTRS)

Kessler, D. J.

1985-01-01

Man-made orbital debris, identified as a potential hazard to future space activities, is grouped into size categories. At least 79 satellites have broken up in orbit to date and, in combination with exploded rocket casings and antisatellite debris, threaten 10 km/sec collisions with other orbiting platforms. Only 5 percent of the debris is connected to payloads. The total population of orbiting objects over 4 cm in diameter could number as high as 15,000, and at 1 cm in diameter could be 32,000, based on NASA and NORAD studies. NASA has initiated the 10 yr Space Debris Assessment Program to characterize the hazards of orbiting debris, the potential damage to typical spacecraft components, and to identify means of controlling the damage.

THE ASTEROID BELT AS A RELIC FROM A CHAOTIC EARLY SOLAR SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izidoro, André; Raymond, Sean N.; Pierens, Arnaud

The orbital structure of the asteroid belt holds a record of the solar system’s dynamical history. The current belt only contains ∼10{sup −3} Earth masses yet the asteroids’ orbits are dynamically excited, with a large spread in eccentricity and inclination. In the context of models of terrestrial planet formation, the belt may have been excited by Jupiter’s orbital migration. The terrestrial planets can also be reproduced without invoking a migrating Jupiter; however, as it requires a severe mass deficit beyond Earth’s orbit, this model systematically under-excites the asteroid belt. Here we show that the orbits of the asteroids may havemore » been excited to their current state if Jupiter’s and Saturn’s early orbits were chaotic. Stochastic variations in the gas giants’ orbits cause resonances to continually jump across the main belt and excite the asteroids’ orbits on a timescale of tens of millions of years. While hydrodynamical simulations show that the gas giants were likely in mean motion resonance at the end of the gaseous disk phase, small perturbations could have driven them into a chaotic but stable state. The gas giants’ current orbits were achieved later, during an instability in the outer solar system. Although it is well known that the present-day solar system exhibits chaotic behavior, our results suggest that the early solar system may also have been chaotic.« less

Precise orbit determination and rapid orbit recovery supported by time synchronization

NASA Astrophysics Data System (ADS)

Guo, Rui; Zhou, JianHua; Hu, XiaoGong; Liu, Li; Tang, Bo; Li, XiaoJie; Wu, Shan

2015-06-01

In order to maintain optimal signal coverage, GNSS satellites have to experience orbital maneuvers. For China's COMPASS system, precise orbit determination (POD) as well as rapid orbit recovery after maneuvers contribute to the overall Positioning, Navigation and Timing (PNT) service performance in terms of accuracy and availability. However, strong statistical correlations between clock offsets and the radial component of a satellite's positions require long data arcs for POD to converge. We propose here a new strategy which relies on time synchronization between ground tracking stations and in-orbit satellites. By fixing satellite clock offsets measured by the satellite station two-way synchronization (SSTS) systems and receiver clock offsets, POD and orbital recovery performance can be improved significantly. Using the Satellite Laser Ranging (SLR) as orbital accuracy evaluation, we find the 4-hr recovered orbit achieves about 0.71 m residual root mean square (RMS) error of fit SLR data, the recovery time is improved from 24-hr to 4-hr compared with the conventional POD without time synchronization support. In addition, SLR evaluation shows that for 1-hr prediction, about 1.47 m accuracy is achieved with the new proposed POD strategy.

The Dynamics of Orbit-Clearing for Planets on Eccentric Orbits

NASA Astrophysics Data System (ADS)

Hastings, Danielle; Margot, Jean-Luc

2016-10-01

The third requirement in the 2006 International Astronomical Union (IAU) definition of a planet is that the object has cleared the neighborhood around its orbit. Margot (2015) proposed a metric that quantitatively determines if an object has enough mass to clear an orbital zone of a specific extent within a defined time interval. In this metric, the size of the zone to be cleared is given by CRH, where C is a constant and RH is the Hill Radius. Margot (2015) adopts C=2*31/2 to describe the minimum extent of orbital clearing on the basis of the planet's feeding zone. However, this value of C may only apply for eccentricities up to about 0.3 (Quillen & Faber 2006). Here, we explore the timescales and boundaries of orbital clearing for planets over a range of orbital eccentricities and planet-star mass ratios using the MERCURY integration package (Chambers 1999). The basic setup for the integrations includes a single planet orbiting a star and a uniform distribution of massless particles extending beyond CRH. The system is integrated for at least 106 revolutions and the massless particles are tracked in order to quantify the timescale and extent of the clearing.

General view of the Orbiter Discovery in the Orbiter Processing ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

General view of the Orbiter Discovery in the Orbiter Processing Facility at Kennedy Space Center showing the payload bay doors open exposing the heat-dissipating radiator panels located on the inside of the payload bay doors. Also in the view is the boom portion of the boom sensor system deployed as part of the return to flight procedures after STS-107 to inspect the orbiter's thermal protection system. The Remote Manipulator System, the "Canadarm", and the airlock are seen in the background of the image. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

Spatial biostratigraphy of NW Pakistan

NASA Astrophysics Data System (ADS)

Shafique, Naseer Ahmed

2001-07-01

Mesozoic to Cenozoic biostratigraphy of NW Pakistan has been conducted in order to document the temporal and spatial relationship between different marine strata with the help of remote sensing and Geographic Information Systems (GIS). These relationships were then used to help distinguish different tectonostratigraphic units in the Waziristan and the Kurram areas located at the northwestern margin of the Indo-Pakistani craton. Extensive biostratigraphic work in the Waziristan and Kurram areas enabled to distinguish five tectonostratigraphic units and two significant unconformities in the study area. Different foraminiferal zones from Early Jurassic to Middle Eocenewere developed, although due to random samples these zones are not continuous in the sedimentary record. However continuous biozonation from the Late Paleocene P4 to the Early Eocene P9 (Bolli, 1985) biozone was observed. It is observed that the Santonian stage is generally missing in the sedimentary sequence, and it is only found in the olistoliths. This implies that during the Campanian stage there was instability in the shelf due to ophiolite obduction, which caused the displacement of the Santonian strata. The absence of Early Paleocene (Zone P1--P3) microfauna is suggested by rapid subsidence of the NW Indian shelf beginning in the early Paleocene. Moreover, index fossils for the Palpha, P1a, b, c, d, P2 and P3 biozones are absent in the melange of the Thal area suggesting regional uplift during the Paleocene. The presence of Planorotalites pseudomenardii P4 zone microfauna above the unconformable Upper Cretaceous Kahi melange strata suggest the India-Asia collision age between 58 Ma--56 Ma. Foraminiferal biostratigraphy of upper Cretaceous olistoliths was conducted from the Mughal Kot gorge, Baluchistan, Pakistan in order to reveal the depositional history of Late Santonian aged (Dicarinella asymmetrica zone) olistoliths and associated upper Cretaceous to early Tertiary Indo-Pakistani shelf strata

LLOFX earth orbit to lunar orbit delta V estimation program user and technical documentation

NASA Technical Reports Server (NTRS)

1988-01-01

The LLOFX computer program calculates in-plane trajectories from an Earth-orbiting space station to Lunar orbit in such a way that the journey requires only two delta V burns (one to leave Earth circular orbit and one to circularize into Lunar orbit). The program requires the user to supply the Space Station altitude and Lunar orbit altitude (in km above the surface), and the desired time of flight for the transfer (in hours). It then determines and displays the trans-Lunar injection (TLI) delta V required to achieve the transfer, the Lunar orbit insertion (LOI) delta V required to circularize the orbit around the Moon, the actual time of flight, and whether the transfer orbit is elliptical or hyperbolic. Return information is also displayed. Finally, a plot of the transfer orbit is displayed.

Mars Climate Orbiter

NASA Technical Reports Server (NTRS)

1998-01-01

The purpose of this mission is to study the climate history and the water distribution of Mars. Beautiful panoramic views of the shuttle on the launch pad, engine ignition, Rocket launch, and the separation and burnout of the Solid Rocket Boosters are shown. The footage also includes an animation of the mission. Detailed views of the path that the Orbiter traversed were shown. Once the Orbiter lands on the surface of Mars, it will dig a six to eight inch hole and collect samples from the planets' surface. The animation also included the prospective return of the Orbiter to Earth over the desert of Utah. The remote sensor on the Orbiter helps in finding the exact location of the Orbiter so that scientists may collect the sample and analyze it.

ALSAT-2A power subsystem behavior during launch, early operation, and in-orbit test

NASA Astrophysics Data System (ADS)

Larbi, N.; Attaba, M.; Beaufume, E.

2012-09-01

In 2006, Algerian Space Agency (ASAL) decided to design and built two optical Earth observation satellites. The first one, ALSAT-2A, was integrated and tested as a training and cooperation program with EADS Astrium. The second satellite ALSAT-2B will be integrated by ASAL engineers in the Satellite Development Center (CDS) at Oran in Algeria. On 12th July 2010, Algeria has launched ALSAT-2A onboard an Indian rocket PSLV-C15 from the Sriharikota launch base, Chennaï. ALSAT-2A is the first Earth observation satellite of the AstroSat-100 family; the design is based on the Myriade platform and comprising the first flight model of the New Astrosat Observation Modular Instrument (NAOMI). This Instrument offers a 2.5m ground resolution for the PAN channel and a 10m ground resolution for four multi-spectral channels which provides high imaging quality. The operations are performed from ALSAT-2 ground segment located in Ouargla (Algeria) and after the test phase ALSAT-2A provides successful images. ALSAT-2A electrical power subsystem (EPS) is composed of a Solar Array Generator (SAG ), a Li-ion battery dedicated to power storage and energy source during eclipse or high consumption phases and a Power Conditioning and Distribution Unit (PCDU). This paper focuses primarily on ALSAT-2A electrical power subsystem behavior during Launch and Early OPeration (LEOP) as well as In Orbit Test (IOT). The telemetry data related to the SAG voltage, current and temperature will be analyzed in addition to battery temperature, voltage, charge and discharge current. These parameters will be studied in function of satellite power consumption.

Three Orbital Burns to Molniya Orbit Via Shuttle_Centaur G Upper Stage

NASA Technical Reports Server (NTRS)

Williams, Craig H.

2015-01-01

An unclassified analytical trajectory design, performance, and mission study was done for the 1982 to 1986 joint National Aeronautics and Space Administration (NASA)-United States Air Force (USAF) Shuttle/Centaur G upper stage development program to send performance-demanding payloads to high orbits such as Molniya using an unconventional orbit transfer. This optimized three orbital burn transfer to Molniya orbit was compared to the then-baselined two burn transfer. The results of the three dimensional trajectory optimization performed include powered phase steering data and coast phase orbital element data. Time derivatives of the orbital elements as functions of thrust components were evaluated and used to explain the optimization's solution. Vehicle performance as a function of parking orbit inclination was given. Performance and orbital element data was provided for launch windows as functions of launch time. Ground track data was given for all burns and coasts including variation within the launch window. It was found that a Centaur with fully loaded propellant tanks could be flown from a 37 deg inclination low Earth parking orbit and achieve Molniya orbit with comparable performance to the baselined transfer which started from a 57 deg inclined orbit: 9,545 versus 9,552 lb of separated spacecraft weight, respectively. There was a significant reduction in the need for propellant launch time reserve for a 1 hr window: only 78 lb for the three burn transfer versus 320 lb for the two burn transfer. Conversely, this also meant that longer launch windows over more orbital revolutions could be done for the same amount of propellant reserve. There was no practical difference in ground tracking station or airborne assets needed to secure telemetric data, even though the geometric locations of the burns varied considerably. There was a significant adverse increase in total mission elapsed time for the three versus two burn transfer (12 vs. 1-1/4 hr), but could be

Three Orbital Burns to Molniya Orbit via Shuttle Centaur G Upper Stage

NASA Technical Reports Server (NTRS)

Williams, Craig H.

2014-01-01

An unclassified analytical trajectory design, performance, and mission study was done for the 1982-86 joint NASA-USAF Shuttle/Centaur G upper stage development program to send performance-demanding payloads to high orbits such as Molniya using an unconventional orbit transfer. This optimized three orbital burn transfer to Molniya orbit was compared to the then-baselined two burn transfer. The results of the three dimensional trajectory optimization performed include powered phase steering data and coast phase orbital element data. Time derivatives of the orbital elements as functions of thrust components were evaluated and used to explain the optimization's solution. Vehicle performance as a function of parking orbit inclination was given. Performance and orbital element data was provided for launch windows as functions of launch time. Ground track data was given for all burns and coasts including variation within the launch window. It was found that a Centaur with fully loaded propellant tanks could be flown from a 37deg inclination low Earth parking orbit and achieve Molniya orbit with comparable performance to the baselined transfer which started from a 57deg inclined orbit: 9,545 lb vs. 9,552 lb of separated spacecraft weight respectively. There was a significant reduction in the need for propellant launch time reserve for a one hour window: only 78 lb for the three burn transfer vs. 320 lb for the two burn transfer. Conversely, this also meant that longer launch windows over more orbital revolutions could be done for the same amount of propellant reserve. There was no practical difference in ground tracking station or airborne assets needed to secure telemetric data, even though the geometric locations of the burns varied considerably. There was a significant adverse increase in total mission elapsed time for the three vs. two burn transfer (12 vs. 11/4 hrs), but could be accommodated by modest modifications to Centaur systems. Future applications were

Artist's Concept of the Orbiting Carbon Observatory

NASA Technical Reports Server (NTRS)

2008-01-01

Artist's concept of the Orbiting Carbon Observatory. The mission, scheduled to launch in early 2009, will be the first spacecraft dedicated to studying atmospheric carbon dioxide, the principal human-produced driver of climate change. It will provide the first global picture of the human and natural sources of carbon dioxide and the places where this important greenhouse gas is stored. Such information will improve global carbon cycle models as well as forecasts of atmospheric carbon dioxide levels and of how our climate may change in the future.

Angles-only relative orbit determination in low earth orbit

NASA Astrophysics Data System (ADS)

Ardaens, Jean-Sébastien; Gaias, Gabriella

2018-06-01

The paper provides an overview of the angles-only relative orbit determination activities conducted to support the Autonomous Vision Approach Navigation and Target Identification (AVANTI) experiment. This in-orbit endeavor was carried out by the German Space Operations Center (DLR/GSOC) in autumn 2016 to demonstrate the capability to perform spaceborne autonomous close-proximity operations using solely line-of-sight measurements. The images collected onboard have been reprocessed by an independent on-ground facility for precise relative orbit determination, which served as ultimate instance to monitor the formation safety and to characterize the onboard navigation and control performances. During two months, several rendezvous have been executed, generating a valuable collection of images taken at distances ranging from 50 km to only 50 m. Despite challenging experimental conditions characterized by a poor visibility and strong orbit perturbations, angles-only relative positioning products could be continuously derived throughout the whole experiment timeline, promising accuracy at the meter level during the close approaches. The results presented in the paper are complemented with former angles-only experience gained with the PRISMA satellites to better highlight the specificities induced by different orbits and satellite designs.

The Climate of Early Mars

NASA Astrophysics Data System (ADS)

Wordsworth, Robin D.

2016-06-01

The nature of the early martian climate is one of the major unanswered questions of planetary science. Key challenges remain, but a new wave of orbital and in situ observations and improvements in climate modeling have led to significant advances over the past decade. Multiple lines of geologic evidence now point to an episodically warm surface during the late Noachian and early Hesperian periods 3-4 Ga. The low solar flux received by Mars in its first billion years and inefficiency of plausible greenhouse gases such as CO2 mean that the steady-state early martian climate was likely cold. A denser CO2 atmosphere would have caused adiabatic cooling of the surface and hence migration of water ice to the higher-altitude equatorial and southern regions of the planet. Transient warming caused melting of snow and ice deposits and a temporarily active hydrological cycle, leading to erosion of the valley networks and other fluvial features. Precise details of the warming mechanisms remain unclear, but impacts, volcanism, and orbital forcing all likely played an important role. The lack of evidence for glaciation across much of Mars's ancient terrain suggests the late Noachian surface water inventory was not sufficient to sustain a northern ocean. Though mainly inhospitable on the surface, early Mars may nonetheless have presented significant opportunities for the development of microbial life.

Family of Orbiters

NASA Technical Reports Server (NTRS)

2008-01-01

This image shows the paths of three spacecraft currently in orbit around Mars, as well as the path by which NASA's Phoenix Mars Lander will approach and land on the planet. The t-shaped crosses show where the orbiters will be when Phoenix enters the atmosphere, while the x-shaped crosses show their location at landing time.

All three orbiters, NASA's Mars Reconnaissance Orbiter, NASA's Mars Odyssey and the European Space Agency's Mars Express, will be monitoring Phoenix during the final steps of its journey to the Red Planet.

Phoenix will land just south of Mars's north polar ice cap.

Eye and orbit ultrasound

MedlinePlus

Echography - eye orbit; Ultrasound - eye orbit; Ocular ultrasonography; Orbital ultrasonography ... eye is numbed with medicine (anesthetic drops). The ultrasound wand (transducer) is placed against the front surface ...

Development of Precise Lunar Orbit Propagator and Lunar Polar Orbiter's Lifetime Analysis

NASA Astrophysics Data System (ADS)

Song, Young-Joo; Park, Sang-Young; Kim, Hae-Dong; Sim, Eun-Sup

2010-06-01

To prepare for a Korean lunar orbiter mission, a precise lunar orbit propagator; Yonsei precise lunar orbit propagator (YSPLOP) is developed. In the propagator, accelerations due to the Moon's non-spherical gravity, the point masses of the Earth, Moon, Sun, Mars, Jupiter and also, solar radiation pressures can be included. The developed propagator's performance is validated and propagation errors between YSPOLP and STK/Astrogator are found to have about maximum 4-m, in along-track direction during 30 days (Earth's time) of propagation. Also, it is found that the lifetime of a lunar polar orbiter is strongly affected by the different degrees and orders of the lunar gravity model, by a third body's gravitational attractions (especially the Earth), and by the different orbital inclinations. The reliable lifetime of circular lunar polar orbiter at about 100 km altitude is estimated to have about 160 days (Earth's time). However, to estimate the reasonable lifetime of circular lunar polar orbiter at about 100 km altitude, it is strongly recommended to consider at least 50 × 50 degrees and orders of the lunar gravity field. The results provided in this paper are expected to make further progress in the design fields of Korea's lunar orbiter missions.

Calibrating the Cretaceous normal superchron with high-precision U-Pb zircon geochronology from Songliao Basin, NE China

NASA Astrophysics Data System (ADS)

Wang, T.; Ramezani, J.; Wang, C.

2017-12-01

The Cretaceous Normal Superchron (CNS) or C34n is defined as the prolonged period of normal geomagnetic polarity, which lasted for approximately 38 Myr from the Aptian to the beginning of the Campanian. Along with the Kiaman Reverse Superchron (Carboniferous-Permian), they constitute the two longest periods of stability in the Earth's magnetic field. Polarity reversals are geologically abrupt events of global extent that form the basis of the Geomagnetic Polarity Timescale. In addition, a causal relationship between the end of a superchron and global environmental change has been hypothesized by some workers. Thus, the precise timing of the onset and termination of CNS has important implications for the correlation of global tectonic, paleoclimatic and paleobiotic events, and may help us better understand the causes and consequences of superchrons. At present, the exact age and duration of CNS are poorly understood, in part due to the relative scarcity of relevant paleomagnetic and radioisotopic data. The end of CNS or the C34n/C33r chron boundary is also considered a suitable proxy for the Santonian-Campanian stage boundary in the absence of diagnostic fossils of global distribution for the latter. The early Campanian ( 84 Ma to 76 Ma) is characterized by a steady cooling of the (greenhouse) climate, preceded by an abrupt (possibly 5-6°C) drop in the global temperatures at the Santonain-Campanian boundary, based on the oxygen isotope record of benthic foraminifera. The peak of dinosaur diversity throughout vast swaths of the continents was reached during the Campanian, as well. Here we present a new age constraint for the termination of CNS based on ash bed geochronology from a near-continuous, subsurface, Cretaceous lacustrine record recovered from the Songliao Basin in Northeast China. This extraordinary record allows integration of high-precision U-Pb geochronology, magnetostratigraphy and cyclostratigraphy that enables a multi-chronometer approach to the

Mars Telecommunications Orbiter, Artist's Concept

NASA Technical Reports Server (NTRS)

2005-01-01

This illustration depicts a concept for NASA's Mars Telecommunications Orbiter in flight around Mars. The orbiter is in development to be the first spacecraft with a primary function of providing communication links while orbiting a foreign planet. The project's plans call for launch in September 2009, arrival at Mars in August 2010 and a mission of six to 10 years while in orbit. Mars Telecommunication Orbiter would serve as the Mars hub for an interplanetery Internet, greatly increasing the information payoff from other future Mars missions. The mission is designed to orbit Mars more than 10 times farther from the planet than orbiters dedicated primarily to science. The high-orbit design minimizes the time that Mars itself blocks the orbiter from communicating with Earth and maximizes the time that the orbiter is above the horizon -- thus capable of communications relay -- for rovers and stationary landers on Mars' surface.

Studies of early-type variable stars. XIV. Spectroscopic orbit and absolute parameters of HU Tauri.

NASA Astrophysics Data System (ADS)

Maxted, P. F. L.; Hill, G.; Hilditch, R. W.

1995-09-01

We present a new spectroscopic orbit for the Algol-type eclipsing binary system HU Tau (HD 29365, P=2.0563 days α(2000.0) = 04 38 15.80, δ= +20 41 05.3, V=5.87-6.8, B8V + G2). We find : m_1_ sin^3^i=4.17+/-0.09Msun_, m_2_ sin^3^i=1.07+/-0.025Msun_, (a_p_+a_s_)sin i=11.8 +/-0.1Rsun_, m_1_/m_2_=3.90+/-0.07. The spectroscopic orbit includes corrections for non-Keplerian effects derived from the solutions of the BV light curves of Ito (1988). We have been able to derive much improved absolute parameters for this system as follows: M_1_=4.43+/-0.09Msun_, M_2_=1.14+/-0.03Msun_, R _1_=2.57+/-0.03Rsun_, R _2_=4.21+/-0.03Rsun_, log(L_1_/Lsun_)= 2.09+/-0.15, log(L_2_/Lsun_)= 0.92+/-0.05. Comparison of HU Tau with non-conservative case B evolution models of De Greve (1993) suggests that the system evolved from an initial mass ratio <~0.5. However, the orbital period of HU Tau is more than 3 days shorter than any of the model systems, and the observed secondary luminosity of order 10 times less than a model star of the same mass during the slow mass transfer phase.

Space station orbit maintenance

NASA Technical Reports Server (NTRS)

Kaplan, D. I.; Jones, R. M.

1983-01-01

The orbit maintenance problem is examined for two low-earth-orbiting space station concepts - the large, manned Space Operations Center (SOC) and the smaller, unmanned Science and Applications Space Platform (SASP). Atmospheric drag forces are calculated, and circular orbit altitudes are selected to assure a 90 day decay period in the event of catastrophic propulsion system failure. Several thrusting strategies for orbit maintenance are discussed. Various chemical and electric propulsion systems for orbit maintenance are compared on the basis of propellant resupply requirements, power requirements, Shuttle launch costs, and technology readiness.

Low drag attitude control for Skylab orbital lifetime extension

NASA Technical Reports Server (NTRS)

Glaese, J. R.; Kennel, H. F.

1981-01-01

In the fall of 1977 it was determined that Skylab had started to tumble and that the original orbit lifetime predictions were much too optimistic. A decision had to be made whether to accept an early uncontrolled reentry with its inherent risks or try to attempt to control Skylab to a lower drag attitude in the hope that there was enough time to develop a Teleoperator Retrieval System, bring it up on the Space Shuttle and then decide whether to boost Skylab to a higher longer life orbit or to reenter it in a controlled fashion. The end-on-velocity (EOVV) control method is documented, which was successfully applied for about half a year to keep Skylab in a low drag attitude with the aid of the control moment gyros and a minimal expenditure of attitude control gas.

Orbit error characteristic and distribution of TLE using CHAMP orbit data

NASA Astrophysics Data System (ADS)

Xu, Xiao-li; Xiong, Yong-qing

2018-02-01

Space object orbital covariance data is required for collision risk assessments, but publicly accessible two line element (TLE) data does not provide orbital error information. This paper compared historical TLE data and GPS precision ephemerides of CHAMP to assess TLE orbit accuracy from 2002 to 2008, inclusive. TLE error spatial variations with longitude and latitude were calculated to analyze error characteristics and distribution. The results indicate that TLE orbit data are systematically biased from the limited SGP4 model. The biases can reach the level of kilometers, and the sign and magnitude are correlate significantly with longitude.

Burn Delay Analysis of the Lunar Orbit Insertion for Korea Pathfinder Lunar Orbiter

NASA Astrophysics Data System (ADS)

Bae, Jonghee; Song, Young-Joo; Kim, Young-Rok; Kim, Bangyeop

2017-12-01

The first Korea lunar orbiter, Korea Pathfinder Lunar Orbiter (KPLO), has been in development since 2016. After launch, the KPLO will execute several maneuvers to enter into the lunar mission orbit, and will then perform lunar science missions for one year. Among these maneuvers, the lunar orbit insertion (LOI) is the most critical maneuver because the KPLO will experience an extreme velocity change in the presence of the Moon’s gravitational pull. However, the lunar orbiter may have a delayed LOI burn during operation due to hardware limitations and telemetry delays. This delayed burn could occur in different captured lunar orbits; in the worst case, the KPLO could fly away from the Moon. Therefore, in this study, the burn delay for the first LOI maneuver is analyzed to successfully enter the desired lunar orbit. Numerical simulations are performed to evaluate the difference between the desired and delayed lunar orbits due to a burn delay in the LOI maneuver. Based on this analysis, critical factors in the LOI maneuver, the periselene altitude and orbit period, are significantly changed and an additional delta-V in the second LOI maneuver is required as the delay burn interval increases to 10 min from the planned maneuver epoch.

New Specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia

PubMed Central

Fanti, Federico; Currie, Philip J.; Badamgarav, Demchig

2012-01-01

Two new specimens of the oviraptorid theropod Nemegtomaia barsboldi from the Nemegt Basin of southern Mongolia are described. Specimen MPC-D 107/15 was collected from the upper beds of the Baruungoyot Formation (Campanian-Maastrichtian), and is a nest of eggs with the skeleton of the assumed parent of Nemegtomaia on top in brooding position. Much of the skeleton was damaged by colonies of dermestid coleopterans prior to its complete burial. However, diagnostic characters are recovered from the parts preserved, including the skull, partial forelimbs (including the left hand), legs, and distal portions of both feet. Nemegtomaia represents the fourth known genus of oviraptorid for which individuals have been found on nests of eggs. The second new specimen, MPC-D 107/16, was collected a few kilometers to the east in basal deposits of the Nemegt Formation, and includes both hands and femora of a smaller Nemegtomaia individual. The two formations and their diverse fossil assemblages have been considered to represent sequential time periods and different environments, but data presented here indicate partial overlap across the Baruungoyot-Nemegt transition. All other known oviraptorids from Mongolia and China are known exclusively from xeric or semi-arid environments. However, this study documents that Nemegtomaia is found in both arid/aeolian (Baruungoyot Formation) and more humid/fluvial (Nemegt Formation) facies. PMID:22347465

Tertiary fission-track ages from the Bagua syncline (northern Peru): Stratigraphic and tectonic implications

NASA Astrophysics Data System (ADS)

Naeser, C. W.; Crochet, J.-Y.; Jaillard, E.; Laubacher, G.; Mourier, T.; Sigé, B.

The results of five zircon fission-track ages of volcanic tuffs intercalated within the continental deposits of the Bagua syncline (northern Peru) are reported. These 2500-meter-thick deposits overlie mid-Campanian to lower Maastrichtian fine-grained red beds (Fundo El Triunfo Formation). The disconformable fluvial conglomerates of the Rentema Formation are associated with a 54 Ma tuff (upper Paleocene-lower Eocene?) and would reflect the Inca-1 tectonic phase. The Sambimera Formation (Eocene to mid-Miocene) is a coarsening-upward sequence (from lacustrine to fluvial) that contains three volcanic tuffs of 31, 29, and 12 Ma, respectively. A probable stratigraphic gap, upper Eocene-lower Oligocene, would be related to the late Eocene Inca-2 phase. Neither deformation nor sedimentary discontinuity has been recognized so far. However, the lacustrine to fluvial transition could relate to the late Oligocene Aymara tectonic phase. The unconformable fanglomerates and fluvial deposits of the San Antonio Formation contain in their upper part a 9 Ma tuff (mid-to upper Miocene), and thier base records a major tectonic event (Quechua-2 phase?). The unconformable fanglomerates of the Tambopara Formation date the folding of the Bagua syncline, which could be ascribed to the latest Miocene Quechua-3 tectonics. These formations are correlative with comparable deposits in the sub-Andean basins, suggesting that these eastern areas underwent strong tectonic subsidence of the foreland basin type since mid-Miocene times.

A comparison of spacecraft penetration hazards due to meteoroids and manmade earth-orbiting objects

NASA Technical Reports Server (NTRS)

Brooks, D. R.

1976-01-01

The ability of a typical double-walled spacecraft structure to protect against penetration by high-velocity incident objects is reviewed. The hazards presented by meteoroids are compared to the current and potential hazards due to manmade orbiting objects. It is shown that the nature of the meteoroid number-mass relationship makes adequate protection for large space facilities a conceptually straightforward structural problem. The present level of manmade orbiting objects (an estimated 10,000 in early 1975) does not pose an unacceptable risk to manned space operations proposed for the near future, but it does produce penetration probabilities in the range of 1-10 percent for a 100-m diameter sphere in orbit for 1,000 days. The number-size distribution of manmade objects is such that adequate protection is difficult to achieve for large permanent space facilities, to the extent that future restrictions on such facilities may result if the growth of orbiting objects continues at its historical rate.

Diverse Orbits Around Mars Graphic

NASA Image and Video Library

2015-05-04

This graphic depicts the relative shapes and distances from Mars for five active orbiter missions plus the planet's two natural satellites. It illustrates the potential for intersections of the spacecraft orbits. The number of active orbiter missions at Mars increased from three to five in 2014. With the increased traffic, NASA has augmented a process for anticipating orbit intersections and avoiding collisions. NASA's Mars Odyssey and MRO (Mars Reconnaissance Orbiter) travel near-circular orbits. The European Space Agency's Mars Express, NASA's MAVEN (Mars Atmosphere and Volatile Evolution) and India's MOM (Mars Orbiter Mission), travel more elliptical orbits. Phobos and Deimos are the two natural moons of Mars. http://photojournal.jpl.nasa.gov/catalog/PIA19396

The Solar Poynting-Robertson Effect On Particles Orbiting Solar System Bodies: Circular Orbits

NASA Technical Reports Server (NTRS)

Rubincam, David P.

2013-01-01

The Poynting-Robertson effect from sunlight impinging directly on a particle which orbits a Solar System body (planet, asteroid, comet) is considered from the Sun's rest frame. There appear to be no significant first-order terms in V(sub b)/c for circular orbits, where V(sub b) is the body's speed in its orbit about the Sun and c is the speed of light, when the particle's orbital semimajor axis is much smaller than the body's orbital semimajor axis about the Sun as is mainly the case in the Solar System.

Mars Reconnaissance Orbiter: Aerobraking Science Discoveries using the Accelerometer

NASA Astrophysics Data System (ADS)

Keating, Gerald M.; Bougher, S. W.

2006-09-01

The Mars Reconnaissance Orbiter (MRO) spacecraft was launched from the Kennedy Space Center in Florida on August 12, 2005, and arrived at Mars on March 10, 2006. Aerobraking in the martian thermosphere was conducted for nearly 5-months after arrival, enabling the desired MRO mapping orbit to be achieved. The MRO aerobraking phase began in early martian northern Spring (Ls = 36) and continued through early northern Summer (Ls 110), spanning approximately 500 orbits. The MRO periapsis latitude migrated slowly poleward/southward from 70ºS latitude upon aerobraking initiation, passed over the South pole (near Ls = 77), and moved rapidly northward to equatorial latitudes at aerobraking conclusion. Upper atmosphere sampling ( 100-200 km) was achieved on the dayside (LT 1900-2000) before polar crossing, and on the nightside (LT = 0200-0300) thereafter. These seasonal and latitude conditions are similar to a subset of those experienced by MGS during its post hiatus aerobraking Phase 2. Derived mass densities, scale heights, and estimated temperatures are the primary data products generated from each aeropass. The most important discovery of MRO aerobraking concerns the sampling of the thermosphere up to 200 km, far higher than previous MGS and Odyssey Accelerometers have achieved. This sampling contributes to the characterization of the Mars exobase region, which is required to predict and interpret atmospheric escape rates. In addition, thermospheric densities at a constant altitude were observed to decrease toward the southern (winter) pole, as expected from previous MGS experience. No winter polar warming was typically observed near the South pole. Thereafter, densities were measured to increase on the nightside as periapsis moved toward the equator. In general, thermospheric variability was observed to increase in the vicinity of the polar vortex boundary ( 70-80ºS), and decreased again inside the vortex (high southern latitudes). Finally, longitude wave features

Hubble Space Telescope On-orbit NiH2 Battery Performance

NASA Technical Reports Server (NTRS)

Rao, Gopalakrishna M.; Krol, Stanley J., Jr.

2002-01-01

This paper summarizes the Hubble Space Telescope (HST) nickel-hydrogen (NiH2) battery performance from launch to the present time. Over the life of HST vehicle configuration, charge system degradation and failures together with thermal design limitations have had a significant effect on the capacity of the HST batteries. Changes made to the charge system configuration in order to protect against power system failures and to maintain battery thermal stability resulted in undercharging of the batteries. This undercharging resulted in decreased usable battery capacity as well as battery cell voltage/capacity divergence. This cell divergence was made evident during on-orbit battery capacity measurements by a relatively shallow slope of the discharge curve following the discharge knee. Early efforts to improve the battery performance have been successful. On-orbit capacity measurement data indicates increases in the usable battery capacity of all six batteries as well as improvements in the battery cell voltage/capacity divergence. Additional measures have been implemented to improve battery performance, however, failures within the HST Power Control Unit (PCU) have prevented verification of battery status. As this PCU fault prevents the execution of on-orbit capacity testing, the HST Project has based the battery capacity on trends, which utilizes previous on-orbit battery capacity test data, for science mission and servicing mission planning. The Servicing Mission 38 (SM-3B) in March 2002 replaced the faulty PCU. Following the servicing mission, on-orbit capacity test resumed. A summary of battery performance is reviewed since launch in this paper.

A Re-Evaluation of the Chasmosaurine Ceratopsid Genus Chasmosaurus (Dinosauria: Ornithischia) from the Upper Cretaceous (Campanian) Dinosaur Park Formation of Western Canada.

PubMed

Campbell, James A; Ryan, Michael J; Holmes, Robert B; Schröder-Adams, Claudia J

2016-01-01

The chasmosaurine ceratopsid Chasmosaurus is known from the Upper Cretaceous (Campanian) Dinosaur Park Formation of southern Alberta and Saskatchewan. Two valid species, Chasmosaurus belli and C. russelli, have been diagnosed by differences in cranial ornamentation. Their validity has been supported, in part, by the reported stratigraphic segregation of chasmosaurines in the Dinosaur Park Formation, with C. belli and C. russelli occurring in discrete, successive zones within the formation. An analysis of every potentially taxonomically informative chasmosaurine specimen from the Dinosaur Park Formation indicates that C. belli and C. russelli have indistinguishable ontogenetic histories and overlapping stratigraphic intervals. Neither taxon exhibits autapomorphies, nor a unique set of apomorphies, but they can be separated and diagnosed by a single phylogenetically informative character-the embayment angle formed by the posterior parietal bars relative to the parietal midline. Although relatively deeply embayed specimens (C. russelli) generally have relatively longer postorbital horncores than specimens with more shallow embayments (C. belli), neither this horncore character nor epiparietal morphology can be used to consistently distinguish every specimen of C. belli from C. russelli. Kosmoceratops is purportedly represented in the Dinosaur Park Formation by a specimen previously referred to Chasmosaurus. The reassignment of this specimen to Kosmoceratops is unsupported here, as it is based on features that are either influenced by taphonomy or within the realm of individual variation for Chasmosaurus. Therefore, we conclude that Kosmoceratops is not present in the Dinosaur Park Formation, but is instead restricted to southern Laramidia, as originally posited.

Low-Cost 3D Printing Orbital Implant Templates in Secondary Orbital Reconstructions.

PubMed

Callahan, Alison B; Campbell, Ashley A; Petris, Carisa; Kazim, Michael

Despite its increasing use in craniofacial reconstructions, three-dimensional (3D) printing of customized orbital implants has not been widely adopted. Limitations include the cost of 3D printers able to print in a biocompatible material suitable for implantation in the orbit and the breadth of available implant materials. The authors report the technique of low-cost 3D printing of orbital implant templates used in complex, often secondary, orbital reconstructions. A retrospective case series of 5 orbital reconstructions utilizing a technique of 3D printed orbital implant templates is presented. Each patient's Digital Imaging and Communications in Medicine data were uploaded and processed to create 3D renderings upon which a customized implant was designed and sent electronically to printers open for student use at our affiliated institutions. The mock implants were sterilized and used intraoperatively as a stencil and mold. The final implant material was chosen by the surgeons based on the requirements of the case. Five orbital reconstructions were performed with this technique: 3 tumor reconstructions and 2 orbital fractures. Four of the 5 cases were secondary reconstructions. Molded Medpor Titan (Stryker, Kalamazoo, MI) implants were used in 4 cases and titanium mesh in 1 case. The stenciled and molded implants were adjusted no more than 2 times before anchored in place (mean 1). No case underwent further revision. The technique and cases presented demonstrate 1) the feasibility and accessibility of low-cost, independent use of 3D printing technology to fashion patient-specific implants in orbital reconstructions, 2) the ability to apply this technology to the surgeon's preference of any routinely implantable material, and 3) the utility of this technique in complex, secondary reconstructions.

Stable low-altitude orbits around Ganymede considering a disturbing body in a circular orbit

NASA Astrophysics Data System (ADS)

Cardoso dos Santos, J.; Carvalho, J. P. S.; Vilhena de Moraes, R.

2014-10-01

Some missions are being planned to visit Ganymede like the Europa Jupiter System Mission that is a cooperation between NASA and ESA to insert the spacecraft JGO (Jupiter Ganymede Orbiter) into Ganymedes orbit. This comprehension of the dynamics of these orbits around this planetary satellite is essential for the success of this type of mission. Thus, this work aims to perform a search for low-altitude orbits around Ganymede. An emphasis is given in polar orbits and it can be useful in the planning of space missions to be conducted around, with respect to the stability of orbits of artificial satellites. The study considers orbits of artificial satellites around Ganymede under the influence of the third-body (Jupiter's gravitational attraction) and the polygenic perturbations like those due to non-uniform distribution of mass (J_2 and J_3) of the main body. A simplified dynamic model for these perturbations is used. The Lagrange planetary equations are used to describe the orbital motion of the artificial satellite. The equations of motion are developed in closed form to avoid expansions in eccentricity and inclination. The results show the argument of pericenter circulating. However, low-altitude (100 and 150 km) polar orbits are stable. Another orbital elements behaved variating with small amplitudes. Thus, such orbits are convenient to be applied to future space missions to Ganymede. Acknowledgments: FAPESP (processes n° 2011/05671-5, 2012/12539-9 and 2012/21023-6).

The Mars Climate Orbiter is prepared for a spin test in the SAEF- 2

NASA Technical Reports Server (NTRS)

1998-01-01

In the Spacecraft Assembly and Encapsulation Facility -2 (SAEF- 2), the Mars Climate Orbiter is in place for its spin test. Targeted for launch aboard a Delta II rocket on Dec. 10, 1998, the orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, which is planned for launch on Jan. 3, 1999. The orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for 687 Earth days. It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface.

The Mars Climate Orbiter is prepared for a spin test in the SAEF- 2

NASA Technical Reports Server (NTRS)

1998-01-01

In the Spacecraft Assembly and Encapsulation Facility -2 (SAEF- 2), workers lower the Mars Climate Orbiter into place on the spin test equipment. Targeted for launch aboard a Delta II rocket on Dec. 10, 1998, the orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, which is planned for launch on Jan. 3, 1999. The orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for 687 Earth days. It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface.

Geographically correlated orbit error

NASA Technical Reports Server (NTRS)

Rosborough, G. W.

1989-01-01

The dominant error source in estimating the orbital position of a satellite from ground based tracking data is the modeling of the Earth's gravity field. The resulting orbit error due to gravity field model errors are predominantly long wavelength in nature. This results in an orbit error signature that is strongly correlated over distances on the size of ocean basins. Anderle and Hoskin (1977) have shown that the orbit error along a given ground track also is correlated to some degree with the orbit error along adjacent ground tracks. This cross track correlation is verified here and is found to be significant out to nearly 1000 kilometers in the case of TOPEX/POSEIDON when using the GEM-T1 gravity model. Finally, it was determined that even the orbit error at points where ascending and descending ground traces cross is somewhat correlated. The implication of these various correlations is that the orbit error due to gravity error is geographically correlated. Such correlations have direct implications when using altimetry to recover oceanographic signals.

Spin-orbit torques from interfacial spin-orbit coupling for various interfaces

NASA Astrophysics Data System (ADS)

Kim, Kyoung-Whan; Lee, Kyung-Jin; Sinova, Jairo; Lee, Hyun-Woo; Stiles, M. D.

2017-09-01

We use a perturbative approach to study the effects of interfacial spin-orbit coupling in magnetic multilayers by treating the two-dimensional Rashba model in a fully three-dimensional description of electron transport near an interface. This formalism provides a compact analytic expression for current-induced spin-orbit torques in terms of unperturbed scattering coefficients, allowing computation of spin-orbit torques for various contexts, by simply substituting scattering coefficients into the formulas. It applies to calculations of spin-orbit torques for magnetic bilayers with bulk magnetism, those with interface magnetism, a normal-metal/ferromagnetic insulator junction, and a topological insulator/ferromagnet junction. It predicts a dampinglike component of spin-orbit torque that is distinct from any intrinsic contribution or those that arise from particular spin relaxation mechanisms. We discuss the effects of proximity-induced magnetism and insertion of an additional layer and provide formulas for in-plane current, which is induced by a perpendicular bias, anisotropic magnetoresistance, and spin memory loss in the same formalism.

Spin-orbit torques from interfacial spin-orbit coupling for various interfaces.

PubMed

Kim, Kyoung-Whan; Lee, Kyung-Jin; Sinova, Jairo; Lee, Hyun-Woo; Stiles, M D

2017-09-01

We use a perturbative approach to study the effects of interfacial spin-orbit coupling in magnetic multilayers by treating the two-dimensional Rashba model in a fully three-dimensional description of electron transport near an interface. This formalism provides a compact analytic expression for current-induced spin-orbit torques in terms of unperturbed scattering coefficients, allowing computation of spin-orbit torques for various contexts, by simply substituting scattering coefficients into the formulas. It applies to calculations of spin-orbit torques for magnetic bilayers with bulk magnetism, those with interface magnetism, a normal metal/ferromagnetic insulator junction, and a topological insulator/ferromagnet junction. It predicts a dampinglike component of spin-orbit torque that is distinct from any intrinsic contribution or those that arise from particular spin relaxation mechanisms. We discuss the effects of proximity-induced magnetism and insertion of an additional layer and provide formulas for in-plane current, which is induced by a perpendicular bias, anisotropic magnetoresistance, and spin memory loss in the same formalism.

Spin-orbit torques from interfacial spin-orbit coupling for various interfaces

PubMed Central

Kim, Kyoung-Whan; Lee, Kyung-Jin; Sinova, Jairo; Lee, Hyun-Woo; Stiles, M. D.

2017-01-01

We use a perturbative approach to study the effects of interfacial spin-orbit coupling in magnetic multilayers by treating the two-dimensional Rashba model in a fully three-dimensional description of electron transport near an interface. This formalism provides a compact analytic expression for current-induced spin-orbit torques in terms of unperturbed scattering coefficients, allowing computation of spin-orbit torques for various contexts, by simply substituting scattering coefficients into the formulas. It applies to calculations of spin-orbit torques for magnetic bilayers with bulk magnetism, those with interface magnetism, a normal metal/ferromagnetic insulator junction, and a topological insulator/ferromagnet junction. It predicts a dampinglike component of spin-orbit torque that is distinct from any intrinsic contribution or those that arise from particular spin relaxation mechanisms. We discuss the effects of proximity-induced magnetism and insertion of an additional layer and provide formulas for in-plane current, which is induced by a perpendicular bias, anisotropic magnetoresistance, and spin memory loss in the same formalism. PMID:29333523

Orbit-attitude coupled motion around small bodies: Sun-synchronous orbits with Sun-tracking attitude motion

NASA Astrophysics Data System (ADS)

Kikuchi, Shota; Howell, Kathleen C.; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

2017-11-01

The motion of a spacecraft in proximity to a small body is significantly perturbed due to its irregular gravity field and solar radiation pressure. In such a strongly perturbed environment, the coupling effect of the orbital and attitude motions exerts a large influence that cannot be neglected. However, natural orbit-attitude coupled dynamics around small bodies that are stationary in both orbital and attitude motions have yet to be observed. The present study therefore investigates natural coupled motion that involves both a Sun-synchronous orbit and Sun-tracking attitude motion. This orbit-attitude coupled motion enables a spacecraft to maintain its orbital geometry and attitude state with respect to the Sun without requiring active control. Therefore, the proposed method can reduce the use of an orbit and attitude control system. This paper first presents analytical conditions to achieve Sun-synchronous orbits and Sun-tracking attitude motion. These analytical solutions are then numerically propagated based on non-linear coupled orbit-attitude equations of motion. Consequently, the possibility of implementing Sun-synchronous orbits with Sun-tracking attitude motion is demonstrated.

Diagrammatic theory of transition of pendulum like systems. [orbit-orbit and spin-orbit gravitational resonance interactions

NASA Technical Reports Server (NTRS)

Yoder, C. F.

1979-01-01

Orbit-orbit and spin-orbit gravitational resonances are analyzed using the model of a rigid pendulum subject to both a time-dependent periodic torque and a constant applied torque. First, a descriptive model of passage through resonance is developed from an examination of the polynomial equation that determines the extremes of the momentum variable. From this study, a probability estimate for capture into libration is derived. Second, a lowest order solution is constructed and compared with the solution obtained from numerical integration. The steps necessary to systematically improve this solution are also discussed. Finally, the effect of a dissipative term in the pendulum equation is analyzed.

Orbital Modification of the Himalia Family during an Early Solar System Dynamical Instability

NASA Astrophysics Data System (ADS)

Li, Daohai; Christou, Apostolos A.

2017-11-01

Among the irregular satellites orbiting Jupiter, the Himalia family is characterized by a high velocity dispersion δ v of several hundred {{m}} {{{s}}}-1 among its members, inconsistent with a collisional origin. Efforts to account for this through internecine gravitational interactions do not readily reproduce this feature. Here, we revisit the problem in the context of recent cosmogonical models, where the giant planets migrated significantly through interaction with a planetesimal disk and suffered encounters with planetesimals and planet-sized objects. Our starting assumption is that family formation either predated this phase or occurred soon after its onset. We simulate numerically the diffusive effect of three distinct populations of perturbers on a set of test particles representing the family: Moon-sized (MPT) and Pluto-sized (PPT) planetesimals, and planetary-mass objects (PMO) with masses typical of ice-giant planets. We find that PPT flybys are inefficient, but encounters with MPTs raise the δ v of ∼60% of our test particles to > 200 {{m}} {{{s}}}-1 with respect to Himalia, in agreement with observations. As MPTs may not have been abundant in the disk, we simulate encounters between Jupiter and PMOs. We find that too few encounters generate less dispersion than MPTs while too many essentially destroy the family. For PMO masses in the range 5{--}20 {m}\\oplus , the family orbital distribution is reproduced by a few tens of encounters.

Orbiting Quarantine Facility. The Antaeus report, summary

NASA Technical Reports Server (NTRS)

1981-01-01

Requirements for handling extraterrestrial samples in an orbiting quarantine facility are examined. The major concepts and findings of the study are outlined. One approach that could be taken for receiving, containing, and analyzing samples returned from the surface of Mars in a mission analogous to the lunar return missions of the late 1960s and early 1970s is described. It constructs a general mission scenario and presents an overall systems design, including an approach to cost assessment. Particular attention is paid to the design of system hardware components and to the elaboration of an experimental protocol.

Gaussian-Type Orbitals versus Slater-Type Orbitals: A Comparison

ERIC Educational Resources Information Center

Magalha~es, Alexandre L.

2014-01-01

The advantages of Gaussian-type orbitals (GTO) over Slater-type orbitals (STO) in quantum chemistry calculations are clarified here by means of a holistic approach. The popular Microsoft Office Excel program was used to create an interactive application with which students are able to explore the features of GTO, including automatic calculations…

Galileo Jupiter approach orbit determination

NASA Technical Reports Server (NTRS)

Miller, J. K.; Nicholson, F. T.

1984-01-01

Orbit determination characteristics of the Jupiter approach phase of the Galileo mission are described. Predicted orbit determination performance is given for the various mission events that occur during Jupiter approach. These mission events include delivery of an atmospheric entry probe, acquisition of probe science data by the Galileo orbiter for relay to earth, delivery of an orbiter to a close encounter of the Galilean satellite Io, and insertion of the orbiter into orbit about Jupiter. The orbit determination strategy and resulting accuracies are discussed for the data types which include Doppler, range, optical imaging of Io, and a new Very Long Baseline Interferometry (VLBI) data type called Differential One-Way Range (DOR).

Design of an unmanned, reusable vehicle to de-orbit debris in Earth orbit

NASA Technical Reports Server (NTRS)

Aziz, Shahed; Cunningham, Timothy W.; Moore-Mccassey, Michelle

1990-01-01

The space debris problem is becoming more important because as orbital missions increase, the amount of debris increases. It was the design team's objective to present alternative designs and a problem solution for a deorbiting vehicle that will alleviate the problem by reducing the amount of large debris in earth orbit. The design team was asked to design a reusable, unmanned vehicle to de-orbit debris in earth orbit. The design team will also construct a model to demonstrate the system configuration and key operating features. The alternative designs for the unmanned, reusable vehicle were developed in three stages: selection of project requirements and success criteria, formulation of a specification list, and the creation of alternatives that would satisfy the standards set forth by the design team and their sponsor. The design team selected a Chain and Bar Shot method for deorbiting debris in earth orbit. The De-orbiting Vehicle (DOV) uses the NASA Orbital Maneuvering Vehicle (OMV) as the propulsion and command modules with the deorbiting module attached to the front.

Applicability of meteor radiant determination methods depending on orbit type. II. Low-eccentric orbits

NASA Astrophysics Data System (ADS)

Svoren, J.; Neslusan, L.; Porubcan, V.

1994-08-01

All known parent bodies of meteor showers belong to bodies moving in high-eccentricity orbits (e => 0.5). Recently, asteroids in low-eccentricity orbits (e < 0.5) approaching the Earth's orbit, were suggested as another population of possible parent bodies of meteor streams. This paper deals with the problem of calculation of meteor radiants connected with the bodies in low-eccentricity orbits from the point of view of optimal results depending on the method applied. The paper is a continuation of our previous analysis of high-eccentricity orbits (Svoren, J., Neslusan, L., Porubcan, V.: 1993, Contrib. Astron. Obs. Skalnate Pleso 23, 23). Some additional methods resulting from mathematical modelling are presented and discussed together with Porter's, Steel-Baggaley's and Hasegawa's methods. In order to be able to compare how suitable the application of the individual radiant determination methods is, it is necessary to determine the accuracy with which they approximate real meteor orbits. To verify the accuracy with which the orbit of a meteoroid with at least one node at 1 AU fits the original orbit of the parent body, the Southworth-Hawkins D-criterion (Southworth, R.B., Hawkins, G.S.: 1963, Smithson. Contr. Astrophys. 7, 261) was applied. D <= 0.1 indicates a very good fit of orbits, 0.1 < D <= 0.2 is considered for a good fit and D > 0.2 means that the fit is rather poor and the change of orbit unrealistic. The optimal method, i.e. the one which results in the smallest D values for the population of low-eccentricity orbits, is that of adjusting the orbit by varying both the eccentricity and perihelion distance. A comparison of theoretical radiants obtained by various methods was made for typical representatives from each group of the NEA (near-Earth asteroids) objects.

Sedna Orbit Comparisons

NASA Technical Reports Server (NTRS)

2004-01-01

These four panels show the location of the newly discovered planet-like object, dubbed 'Sedna,' which lies in the farthest reaches of our solar system. Each panel, moving counterclockwise from the upper left, successively zooms out to place Sedna in context. The first panel shows the orbits of the inner planets, including Earth, and the asteroid belt that lies between Mars and Jupiter. In the second panel, Sedna is shown well outside the orbits of the outer planets and the more distant Kuiper Belt objects. Sedna's full orbit is illustrated in the third panel along with the object's current location. Sedna is nearing its closest approach to the Sun; its 10,000 year orbit typically takes it to far greater distances. The final panel zooms out much farther, showing that even this large elliptical orbit falls inside what was previously thought to be the inner edge of the Oort cloud. The Oort cloud is a spherical distribution of cold, icy bodies lying at the limits of the Sun's gravitational pull. Sedna's presence suggests that this Oort cloud is much closer than scientists believed.

Orbit Alignment in Triple Stars

NASA Astrophysics Data System (ADS)

Tokovinin, Andrei

2017-08-01

The statistics of the angle Φ between orbital angular momenta in hierarchical triple systems with known inner visual or astrometric orbits are studied. A correlation between apparent revolution directions proves the partial orbit alignment known from earlier works. The alignment is strong in triples with outer projected separation less than ˜50 au, where the average Φ is about 20^\\circ . In contrast, outer orbits wider than 1000 au are not aligned with the inner orbits. It is established that the orbit alignment decreases with the increasing mass of the primary component. The average eccentricity of inner orbits in well-aligned triples is smaller than in randomly aligned ones. These findings highlight the role of dissipative interactions with gas in defining the orbital architecture of low-mass triple systems. On the other hand, chaotic dynamics apparently played a role in shaping more massive hierarchies. The analysis of projected configurations and triples with known inner and outer orbits indicates that the distribution of Φ is likely bimodal, where 80% of triples have {{Φ }}< 70^\\circ and the remaining ones are randomly aligned.

New osculating orbits for 110 comets and analysis of original orbits for 200 comets

NASA Technical Reports Server (NTRS)

Marsden, B. G.; Sekanina, Z.; Everhart, E.

1978-01-01

Osculating orbits are presented for 110 nearly parabolic comets. Combining these with selected orbit determinations from other sources, a total of 200 orbits are considered where the available observations yield a result of very good (first-class) or good (second-class) quality. For each of these, the original and future orbits (referred to the barycenter of the solar system) are calculated. The Oort effect (a tendency for original reciprocal semimajor axis values to range from zero to +100 millionths per AU) is clearly seen among the first-class orbits but not among the second-class orbits. Modifications in original reciprocal semimajor axis values due to the effects of nongravitational forces are considered.

Preliminary orbital parallax catalog

NASA Technical Reports Server (NTRS)

Halliwell, M.

1981-01-01

The study is undertaken to calibrate the more reliable parallaxes derived from a comparison of visual and spectroscopic orbits and to encourage observational studies of other promising binaries. The methodological techniques used in computing orbital parallaxes are analyzed. Tables summarizing orbital data and derived system properties are then given. Also given is a series of detailed discussions of the 71 individual systems included in the tables. Data are listed for 57 other systems which are considered promising candidates for eventual orbital parallax determination.

Thermal control evaluation of a Shuttle Orbiter solar observatory using Skylab ATM backup hardware

NASA Technical Reports Server (NTRS)

Class, C. R.; Presta, G.; Trucks, H.

1975-01-01

A study under the sponsorship of Marshall Space Flight Center (MSFC) established the feasibility to utilize the Skylab Apollo Telescope Mount (ATM) backup hardware for early low cost Shuttle Orbiter solar observation missions. A solar inertial attitude and a seven-day, full sun exposure were baselined. As a portion of the study, a series of thermal control evaluations were performed to resolve the problems caused by the relocation of the ATM to the Shuttle Orbiter bay and resulting configuration changes. Thermal control requirements, problems, the use of solar shields, Spacelab supplied fluid cooling and component placement are discussed.

Binary Star Orbits. V. The Nearby White Dwarf/Red Dwarf Pair 40 Eri BC

NASA Astrophysics Data System (ADS)

Mason, Brian D.; Hartkopf, William I.; Miles, Korie N.

2017-11-01

A new relative orbit solution with new dynamical masses is determined for the nearby white dwarf-red dwarf pair 40 Eri BC. The period is 230.09 ± 0.68 years. It is predicted to close slowly over the next half-century, getting as close as 1.″32 in early 2066. We determine masses of 0.575 ± 0.018 {{ M }}⊙ for the white dwarf and 0.2041 ± 0.0064 {{ M }}⊙ for the red dwarf companion. The inconsistency of the masses determined by gravitational redshift and dynamical techniques, due to a premature orbit calculation, no longer exists.

The Mars Climate Orbiter awaits launch from Pad 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

After launch tower retraction, the Boeing Delta II rocket carrying NASA's Mars Climate Orbiter undergoes final preparations for liftoff on Dec. 11, 1998, at Launch Complex 17A, Cape Canaveral Air Station. The launch was delayed one day when personnel detected a battery-related software problem in the spacecraft. The problem was corrected and the launch was rescheduled for the next day. The first of a pair of spacecraft in the Mars Surveyor '98 Project, the orbiter is heading for Mars where it will first provide support to its companion Mars Polar Lander spacecraft, which is planned for launch on Jan. 3, 1999. The orbiter's instruments will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface.

Five Equivalent d Orbitals

ERIC Educational Resources Information Center

Pauling, Linus; McClure, Vance

1970-01-01

Amplifies and clarifies a previous paper on pyramidal d orbitals. Discusses two sets of pyramid d orbitals with respect to their maximum bond strength and their symmetry. Authors described the oblate and prolate pentagonal antiprisms arising from the two sets of five equivalent d orbitals. (RR)

Orbital relaxation effects on Kohn–Sham frontier orbital energies in density functional theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, DaDi; Zheng, Xiao, E-mail: xz58@ustc.edu.cn; Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026

2015-04-21

We explore effects of orbital relaxation on Kohn–Sham frontier orbital energies in density functional theory by using a nonempirical scaling correction approach developed in Zheng et al. [J. Chem. Phys. 138, 174105 (2013)]. Relaxation of Kohn–Sham orbitals upon addition/removal of a fractional number of electrons to/from a finite system is determined by a systematic perturbative treatment. The information of orbital relaxation is then used to improve the accuracy of predicted Kohn–Sham frontier orbital energies by Hartree–Fock, local density approximation, and generalized gradient approximation methods. The results clearly highlight the significance of capturing the orbital relaxation effects. Moreover, the proposed scalingmore » correction approach provides a useful way of computing derivative gaps and Fukui quantities of N-electron finite systems (N is an integer), without the need to perform self-consistent-field calculations for (N ± 1)-electron systems.« less

Marned Orbital Systems Concept

NASA Technical Reports Server (NTRS)

1975-01-01

Despite the indefinite postponement of the Space Station in 1972, Marshall Space Flight Center (MSFC) continued to look to the future for some type of orbital facility during the post-Skylab years. In 1975, the MSFC directed a contract with the McDonnel Douglas Aerospace Company for the Manned Orbital Systems Concept (MOSC) study. This 9-month effort examined the requirements for, and defined a cost-effective orbital facility concept capable of, supporting extended manned missions in Earth orbit. The capabilities of this concept exceeded those envisioned for the Space Shuttle and Spacelab, both of which were limited by a 7 to 30-day orbital time constraint. The MOSC's initial operating capability was to be achieved in late 1984. A crew of four would man a four-module configuration. During its five-year orbital life the MOSC would have the capability to evolve into a larger 12-to-24-man facility. This is an artist's concept of MOSC.

Observing orbital debris using space-based telescopes. I - Mission orbit considerations

NASA Technical Reports Server (NTRS)

Reynolds, Robert C.; Talent, David L.; Vilas, Faith

1989-01-01

In this paper, mission orbit considerations are addressed for using the Space Shuttle as a telescope platform for observing man-made orbital debris. Computer modeling of various electrooptical systems predicts that such a space-borne system will be able to detect particles as small as 1-mm diameter. The research is meant to support the development of debris- collision warning sensors through the acquisition of spatial distribution and spectral characteristics for debris and testing of detector combinations on a shuttle-borne telescopic experiment. The technique can also be applied to low-earth-orbit-debris environment monitoring systems. It is shown how the choice of mission orbit, season of launch, and time of day of launch may be employed to provide extended periods of favorable observing conditions.

Orbital-2 Mission

NASA Image and Video Library

2014-07-11

The Orbital Sciences Corporation Antares rocket, with the Cygnus spacecraft onboard, is seen on launch Pad-0A, Friday, July 11, 2014, at NASA's Wallops Flight Facility in Virginia. The Antares will launch with the Cygnus spacecraft filled with over 3,000 pounds of supplies for the International Space Station, including science experiments, experiment hardware, spare parts, and crew provisions. The Orbital-2 mission is Orbital Sciences' second contracted cargo delivery flight to the space station for NASA. Photo Credit: (NASA/Bill Ingalls)

Orbital-2 Mission

NASA Image and Video Library

2014-07-12

The Orbital Sciences Corporation Antares rocket, with the Cygnus spacecraft onboard, is seen, Saturday, July 12, 2014, at launch Pad-0A of NASA's Wallops Flight Facility in Virginia. The Antares will launch with the Cygnus spacecraft filled with over 3,000 pounds of supplies for the International Space Station, including science experiments, experiment hardware, spare parts, and crew provisions. The Orbital-2 mission is Orbital Sciences' second contracted cargo delivery flight to the space station for NASA. Photo Credit: (NASA/Bill Ingalls)

Neonatal orbital abscess

PubMed Central

Al-Salem, Khalil M; Alsarayra, Fawaz A; Somkawar, Areej R

2014-01-01

Orbital complications due to ethmoiditis are rare in neonates. A case of orbital abscess due to acute ethmoiditis in a 28-day-old girl is presented. A Successful outcome was achieved following antimicrobial therapy alone; spontaneous drainage of the abscess occurred from the lower lid without the need for surgery. From this case report, we intend to emphasize on eyelid retraction as a sign of neonatal orbital abscess, and to review all the available literature of similar cases. PMID:24008806

Hypersonic aerodynamic characteristics of NR-ATP orbiter, orbiter with external tank, and ascent configuration

NASA Technical Reports Server (NTRS)

Ashby, G. C., Jr.

1973-01-01

A scale model of the North American Rockwell ATP Orbiter with and without the external tank has been tested in a 22-inch helium tunnel at Mach 20 and a Reynolds number based on model length, of 2.14 times one million. Longitudinal and lateral-directional data were determined for the orbiter alone while only longitudinal characteristics and elevon roll effectiveness were investigated for the orbiter/tank combination. Oil flow and electron beam flow visualization studies were conducted for the orbiter alone, orbiter with external tank and the ascent configuration.

The Mars Climate Orbiter launches from Pad 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

A Boeing Delta II expendable launch vehicle lifts off with NASA's Mars Climate Orbiter at 1:45:51 p.m. EST, on Dec. 11, 1998, from Launch Complex 17A, Cape Canaveral Air Station. The launch was delayed one day when personnel detected a battery-related software problem in the spacecraft. The problem was corrected and the launch was rescheduled for the next day. The first of a pair of spacecraft to be launched in the Mars Surveyor '98 Project, the orbiter is heading for Mars where it will first provide support to its companion Mars Polar Lander spacecraft, which is planned for launch on Jan. 3, 1999. The orbiter's instruments will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface.

Precise orbit determination of the Lunar Reconnaissance Orbiter and first gravity field results

NASA Astrophysics Data System (ADS)

Maier, Andrea; Baur, Oliver

2014-05-01

The Lunar Reconnaissance Orbiter (LRO) was launched in 2009 and is expected to orbit the Moon until the end of 2014. Among other instruments, LRO has a highly precise altimeter on board demanding an orbit accuracy of one meter in the radial component. Precise orbit determination (POD) is achieved with radiometric observations (Doppler range rates, ranges) on the one hand, and optical laser ranges on the other hand. LRO is the first satellite at a distance of approximately 360 000 to 400 000 km from the Earth that is routinely tracked with optical laser ranges. This measurement type was introduced to achieve orbits of higher precision than it would be possible with radiometric observations only. In this contribution we investigate the strength of each measurement type (radiometric range rates, radiometric ranges, optical laser ranges) based on single-technique orbit estimation. In a next step all measurement types are combined in a joined analysis. In addition to POD results, preliminary gravity field coefficients are presented being a subsequent product of the orbit determination process. POD and gravity field estimation was accomplished with the NASA/GSFC software packages GEODYN and SOLVE.

Orbital Debris: A Policy Perspective

NASA Technical Reports Server (NTRS)

Johnson, Nicholas L.

2007-01-01

A viewgraph presentation describing orbital debris from a policy perspective is shown. The contents include: 1) Voyage through near-Earth Space-animation; 2) What is Orbital Debris?; 3) Orbital Debris Detectors and Damage Potential; 4) Hubble Space Telescope; 5) Mir Space Station Solar Array; 6) International Space Station; 7) Space Shuttle; 8) Satellite Explosions; 9) Satellite Collisions; 10) NASA Orbital Debris Mitigation Guidelines; 11) International Space Station Jettison Policy; 12) Controlled/Uncontrolled Satellite Reentries; 13) Return of Space Objects; 14) Orbital Debris and U.S. National Space Policy; 15) U.S Government Policy Strategy; 16) Bankruptcy of the Iridium Satellite System; 17) Inter-Agency Space Debris Coordination Committee (IADC); 18) Orbital Debris at the United Nations; 19) Chinese Anti-satellite System; 20) Future Evolution of Satellite Population; and 21) Challenge of Orbital Debris

Maintaining Aura's Orbit Requirements While Performing Orbit Maintenance Maneuvers Containing an Orbit Normal Delta-V Component

NASA Technical Reports Server (NTRS)

Johnson, Megan R.; Petersen, Jeremy D.

2014-01-01

The Earth Observing System (EOS) Afternoon Constellation consists of five member missions (GCOM-W1, Aqua, CALIPSO, CloudSat, and Aura), each of which maintain a frozen, sun-synchronous orbit with a 16-day repeating ground track that follows the Worldwide Reference System-2 (WRS-2). Under nominal science operations for Aura, the propulsion system is oriented such that the resultant thrust vector is aligned 13.493 degrees away from the velocity vector along the yaw axis. When performing orbit maintenance maneuvers, the spacecraft performs a yaw slew to align the thrust vector in the appropriate direction. A new Drag Make Up (DMU) maneuver operations scheme has been implemented for Aura alleviating the need for the 13.493 degree yaw slew. The focus of this investigation is to assess the impact that no-slew DMU maneuver operations will have on Aura's Mean Local Time (MLT) which drives the required along track separation between Aura and the constellation members, as well as Aura's frozen orbit properties, eccentricity and argument of perigee. Seven maneuver strategies were analyzed to determine the best operational approach. A mirror pole strategy, with maneuvers alternating at the North and South poles, was implemented operationally to minimize impact to the MLT. Additional analysis determined that the mirror pole strategy could be further modified to include frozen orbit maneuvers and thus maintain both MLT and the frozen orbit properties under noslew operations.

Precise orbits of the Lunar Reconnaissance Orbiter from radiometric tracking data

NASA Astrophysics Data System (ADS)

Löcher, Anno; Kusche, Jürgen

2018-02-01

Since 2009, the Lunar Reconnaissance Orbiter (LRO) acquires images and altimetric profiles of the lunar surface. Assembling these data to maps and terrain models requires the precise knowledge of the spacecraft trajectory. In this contribution, we present 5 years of LRO orbits from radiometric data processed with a software tailored to this mission. The presented orbits are the first independent validation of the LRO science orbits from NASA and are available for public use. A key feature of our processing is the elaborate treatment of model and observation errors by empirical parameters and an adaptive data weighting by variance component estimation. The quality of the resulting orbits is assessed by analyzing overlapping arcs. For our solution based on arcs of 2.5 days, such analysis yields a mean error of 2.81 m in total position and 0.11 m in radial direction. It is shown that this result greatly benefits from the adaptive data weighting, reducing the error by 2.54 and 0.13 m, respectively. Unfortunately, the precision achieved varies strongly, dependent on the view onto the orbital ellipse which changes with the lunar cycle. To mitigate this dependency, the arc length was extended in steps up to 10.5 days, leading in the best case to a further improvement of 0.80 m.

Design and Optimization of Low-thrust Orbit Transfers Using Q-law and Evolutionary Algorithms

NASA Technical Reports Server (NTRS)

Lee, Seungwon; vonAllmen, Paul; Fink, Wolfgang; Petropoulos, Anastassios; Terrile, Richard

2005-01-01

Future space missions will depend more on low-thrust propulsion (such as ion engines) thanks to its high specific impulse. Yet, the design of low-thrust trajectories is complex and challenging. Third-body perturbations often dominate the thrust, and a significant change to the orbit requires a long duration of thrust. In order to guide the early design phases, we have developed an efficient and efficacious method to obtain approximate propellant and flight-time requirements (i.e., the Pareto front) for orbit transfers. A search for the Pareto-optimal trajectories is done in two levels: optimal thrust angles and locations are determined by Q-law, while the Q-law is optimized with two evolutionary algorithms: a genetic algorithm and a simulated-annealing-related algorithm. The examples considered are several types of orbit transfers around the Earth and the asteroid Vesta.

The Mars Climate Orbiter is prepared for a spin test in the SAEF- 2

NASA Technical Reports Server (NTRS)

1998-01-01

In the Spacecraft Assembly and Encapsulation Facility -2 (SAEF- 2), a worker maneuvers the Mars Climate Orbiter, suspended by an overhead crane, to the spin test equipment at lower right. Targeted for launch aboard a Delta II rocket on Dec. 10, 1998, the orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, which is planned for launch on Jan. 3, 1999. The orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for 687 Earth days. It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface.

The Mars Climate Orbiter is prepared for a spin test in the SAEF- 2

NASA Technical Reports Server (NTRS)

1998-01-01

In the Spacecraft Assembly and Encapsulation Facility -2 (SAEF- 2), the Mars Climate Orbiter is lifted from the workstand to move it to another site for a spin test. Targeted for launch aboard a Delta II rocket on Dec. 10, 1998, the orbiter is heading for Mars where it will primarily support its companion Mars Polar Lander spacecraft, which is planned for launch on Jan. 3, 1999. The orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for 687 Earth days. It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface.

Classification of orbital morphology for decompression surgery in Graves' orbitopathy: two-dimensional versus three-dimensional orbital parameters.

PubMed

Borumandi, Farzad; Hammer, Beat; Noser, Hansrudi; Kamer, Lukas

2013-05-01

Three-dimensional (3D) CT reconstruction of the bony orbit for accurate measurement and classification of the complex orbital morphology may not be suitable for daily practice. We present an easily measurable two-dimensional (2D) reference dataset of the bony orbit for study of individual orbital morphology prior to decompression surgery in Graves' orbitopathy. CT images of 70 European adults (140 orbits) with unaffected orbits were included. On axial views, the following orbital dimensions were assessed: orbital length (OL), globe length (GL), GL/OL ratio and cone angle. Postprocessed CT data were required to measure the corresponding 3D orbital parameters. The 2D and 3D orbital parameters were correlated. The 2D orbital parameters were significantly correlated to the corresponding 3D parameters (significant at the 0.01 level). The average GL was 25 mm (SD±1.0), the average OL was 42 mm (SD±2.0) and the average GL/OL ratio was 0.6 (SD±0.03). The posterior cone angle was, on average, 50.2° (SD±4.1). Three orbital sizes were classified: short (OL≤40 mm), medium (OL>40 to <45 mm) and large (OL≥45 mm). We present easily measurable reference data for the orbit that can be used for preoperative study and classification of individual orbital morphology. A short and shallow orbit may require a different decompression technique than a large and deep orbit. Prospective clinical trials are needed to demonstrate how individual orbital morphology affects the outcome of decompression surgery.

Orbital-2 Mission

NASA Image and Video Library

2014-07-12

The full Moon sets in the fog behind the Orbital Sciences Corporation Antares rocket, with the Cygnus spacecraft onboard, Saturday, July 12, 2014, launch Pad-0A, NASA's Wallops Flight Facility in Virginia. The Antares will launch with the Cygnus spacecraft filled with over 3,000 pounds of supplies for the International Space Station, including science experiments, experiment hardware, spare parts, and crew provisions. The Orbital-2 mission is Orbital Sciences' second contracted cargo delivery flight to the space station for NASA. Photo Credit: (NASA/Bill Ingalls)

Orbital-2 Mission

NASA Image and Video Library

2014-07-12

The Orbital Sciences Corporation Antares rocket, with the Cygnus spacecraft onboard, is seen during sunrise, Saturday, July 12, 2014, at launch Pad-0A of NASA's Wallops Flight Facility in Virginia. The Antares will launch with the Cygnus spacecraft filled with over 3,000 pounds of supplies for the International Space Station, including science experiments, experiment hardware, spare parts, and crew provisions. The Orbital-2 mission is Orbital Sciences' second contracted cargo delivery flight to the space station for NASA. Photo Credit: (NASA/Bill Ingalls)

Satellite laser ranging to low Earth orbiters: orbit and network validation

NASA Astrophysics Data System (ADS)

Arnold, Daniel; Montenbruck, Oliver; Hackel, Stefan; Sośnica, Krzysztof

2018-04-01

Satellite laser ranging (SLR) to low Earth orbiters (LEOs) provides optical distance measurements with mm-to-cm-level precision. SLR residuals, i.e., differences between measured and modeled ranges, serve as a common figure of merit for the quality assessment of orbits derived by radiometric tracking techniques. We discuss relevant processing standards for the modeling of SLR observations and highlight the importance of line-of-sight-dependent range corrections for the various types of laser retroreflector arrays. A 1-3 cm consistency of SLR observations and GPS-based precise orbits is demonstrated for a wide range of past and present LEO missions supported by the International Laser Ranging Service (ILRS). A parameter estimation approach is presented to investigate systematic orbit errors and it is shown that SLR validation of LEO satellites is not only able to detect radial but also along-track and cross-track offsets. SLR residual statistics clearly depend on the employed precise orbit determination technique (kinematic vs. reduced-dynamic, float vs. fixed ambiguities) but also reveal pronounced differences in the ILRS station performance. Using the residual-based parameter estimation approach, corrections to ILRS station coordinates, range biases, and timing offsets are derived. As a result, root-mean-square residuals of 5-10 mm have been achieved over a 1-year data arc in 2016 using observations from a subset of high-performance stations and ambiguity-fixed orbits of four LEO missions. As a final contribution, we demonstrate that SLR can not only validate single-satellite orbit solutions but also precise baseline solutions of formation flying missions such as GRACE, TanDEM-X, and Swarm.

Orbital Debris: A Chronology

NASA Technical Reports Server (NTRS)

Portree, Davis S. F. (Editor); Loftus, Joseph P., Jr. (Editor)

1999-01-01

This chronology covers the 37-year history of orbital debris concerns. It tracks orbital debris hazard creation, research, observation, experimentation, management, mitigation, protection, and policy. Included are debris-producing, events; U.N. orbital debris treaties, Space Shuttle and space station orbital debris issues; ASAT tests; milestones in theory and modeling; uncontrolled reentries; detection system development; shielding development; geosynchronous debris issues, including reboost policies: returned surfaces studies, seminar papers reports, conferences, and studies; the increasing effect of space activities on astronomy; and growing international awareness of the near-Earth environment.

The Mars Reconnaissance Orbiter Mission: 10 Years of Exploration from Mars Orbit

NASA Technical Reports Server (NTRS)

Johnston, M. Daniel; Zurek, Richard W.

2016-01-01

The Mars Reconnaissance Orbiter ( MRO ) entered Mars orbit on March 10, 2006. After five months of aerobraking, a series of propulsive maneuvers were used to establish the desired low -altitude science orbit. The spacecraft has been on station in its 255 x 320 k m, sun -synchronous (approximately 3 am -pm ), primary science orbit since September 2006 performing both scientific and Mars programmatic support functions. This paper will provide a summary of the major achievements of the mission to date and the major flight activities planned for the remainder of its third Extended Mission (EM3). Some of the major flight challenges the flight team has faced are also discussed.

Primary sporadic Burkitt lymphoma of the orbit, clinical characteristics, management, and outcomes: a case study.

PubMed

Bouali, Sofiene; Said, Imed Ben; Yedeas, Mohamed Dahmani; Abderrahmen, Khansa; Maatar, Nidhal; Boubaker, Adnen; Kallel, Jalel; Jemel, Hafedh

2016-03-01

Involvement of the orbit with Burkitt's lymphoma is a very rare presentation of extra-nodal lymphoma. We report a case of a 2-year-old female presented an unusual location of sporadic Burkitt's lymphoma arising in the orbital region. Diagnostic magnetic resonance imagining identified an oval-shaped mass on the lateral rectus of the right orbit that caused dislocation of eyeball, for which she underwent a biopsy from the periorbital swellings. The mass was histologically confirmed as Burkitt's lymphoma, and postoperative aggressive chemotherapy was initiated. We describe clinical diagnosis, histological aspects, radiological features, and current management of this rapidly growing malignant tumor. Because of the rapid progression of Burkitt lymphoma, and considering that it responds well to treatment, early recognition and appropriate management are important factors for survival and to preserve visual function.

Sedna Orbit Comparisons

NASA Image and Video Library

2004-03-15

These four panels show the location of the newly discovered planet-like object, dubbed "Sedna," which lies in the farthest reaches of our solar system. Each panel, moving counterclockwise from the upper left, successively zooms out to place Sedna in context. The first panel shows the orbits of the inner planets, including Earth, and the asteroid belt that lies between Mars and Jupiter. In the second panel, Sedna is shown well outside the orbits of the outer planets and the more distant Kuiper Belt objects. Sedna's full orbit is illustrated in the third panel along with the object's current location. Sedna is nearing its closest approach to the Sun; its 10,000 year orbit typically takes it to far greater distances. The final panel zooms out much farther, showing that even this large elliptical orbit falls inside what was previously thought to be the inner edge of the Oort cloud. The Oort cloud is a spherical distribution of cold, icy bodies lying at the limits of the Sun's gravitational pull. Sedna's presence suggests that this Oort cloud is much closer than scientists believed. http://photojournal.jpl.nasa.gov/catalog/PIA05569

Orbiter entry aerothermodynamics

NASA Technical Reports Server (NTRS)

Ried, R. C.

1985-01-01

The challenge in the definition of the entry aerothermodynamic environment arising from the challenge of a reliable and reusable Orbiter is reviewed in light of the existing technology. Select problems pertinent to the orbiter development are discussed with reference to comprehensive treatments. These problems include boundary layer transition, leeward-side heating, shock/shock interaction scaling, tile gap heating, and nonequilibrium effects such as surface catalysis. Sample measurements obtained from test flights of the Orbiter are presented with comparison to preflight expectations. Numerical and wind tunnel simulations gave efficient information for defining the entry environment and an adequate level of preflight confidence. The high quality flight data provide an opportunity to refine the operational capability of the orbiter and serve as a benchmark both for the development of aerothermodynamic technology and for use in meeting future entry heating challenges.

Ionospheric refraction effects on orbit determination using the orbit determination error analysis system

NASA Technical Reports Server (NTRS)

Yee, C. P.; Kelbel, D. A.; Lee, T.; Dunham, J. B.; Mistretta, G. D.

1990-01-01

The influence of ionospheric refraction on orbit determination was studied through the use of the Orbit Determination Error Analysis System (ODEAS). The results of a study of the orbital state estimate errors due to the ionospheric refraction corrections, particularly for measurements involving spacecraft-to-spacecraft tracking links, are presented. In current operational practice at the Goddard Space Flight Center (GSFC) Flight Dynamics Facility (FDF), the ionospheric refraction effects on the tracking measurements are modeled in the Goddard Trajectory Determination System (GTDS) using the Bent ionospheric model. While GTDS has the capability of incorporating the ionospheric refraction effects for measurements involving ground-to-spacecraft tracking links, such as those generated by the Ground Spaceflight Tracking and Data Network (GSTDN), it does not have the capability to incorporate the refraction effects for spacecraft-to-spacecraft tracking links for measurements generated by the Tracking and Data Relay Satellite System (TDRSS). The lack of this particular capability in GTDS raised some concern about the achievable accuracy of the estimated orbit for certain classes of spacecraft missions that require high-precision orbits. Using an enhanced research version of GTDS, some efforts have already been made to assess the importance of the spacecraft-to-spacecraft ionospheric refraction corrections in an orbit determination process. While these studies were performed using simulated data or real tracking data in definitive orbit determination modes, the study results presented here were obtained by means of covariance analysis simulating the weighted least-squares method used in orbit determination.

Amphibian, reptilian, and avian remains from the Fox Hills Formation (Maastrichtian): Shoreline and estuarine deposits of the Pierre Sea in south-central North Dakota

USGS Publications Warehouse

Hoganson, J.W.; Erickson, J.M.; Holland, F.D.

2007-01-01

Although vertebrate fossils, except for fish, are not common in the Maastrichtian Fox Hills Formation, amphibian, reptilian, and avian remains have been recovered at several localities in south-central North Dakota from shoreline facies of the retreating Pierre-Fox Hills seaway. This mixed fauna of aquatic, terrestrial, and marine taxa provides insight into the composition of coastal communities and habitats at the interface between the Hell Creek delta and the Western Interior Seaway. The delta-platform aquatic paleocommunity is represented by the efficient swimming salamanders Opistho- trition kayi and Lisserpeton bairdi, the carnivorous soft-shelled turtle "Aspideretes" sensu lato, the underwater piscivorous predator Champsosaurus laramiensis, and the large, predatory crocodile IBorealosuchus. Terrestrial areas were inhabited by the tortoise-like Basilemys and the predatory dinosaurs Tyrannosaurus and cf. Saurornit- holestes. Birds occupied niches in the warm-temperate to subtropical, forested delta platform and shoreline areas. These nonmarine taxa in the Fox Hills Formation indicate that the geographic range of these animals extended to shoreline areas of the Western Interior Seaway. The toxochelyid turtle Lophochelys and the ambush predators Mosasaurus dekayi and IPlioplatecarpus resided in the shallow marine and estuarine habitats. These taxa and marine fish taxa reported earlier indicate that normal marine conditions in south- central North Dakota persisted into the latest Late Cretaceous in comparison with coeval Hell Creek Formation sites more distal from the Western Interior Seaway. ?? 2007 The Geological Society of America. All rights reserved.

Validation of Galileo orbits using SLR with a focus on satellites launched into incorrect orbital planes

NASA Astrophysics Data System (ADS)

Sośnica, Krzysztof; Prange, Lars; Kaźmierski, Kamil; Bury, Grzegorz; Drożdżewski, Mateusz; Zajdel, Radosław; Hadas, Tomasz

2018-02-01

The space segment of the European Global Navigation Satellite System (GNSS) Galileo consists of In-Orbit Validation (IOV) and Full Operational Capability (FOC) spacecraft. The first pair of FOC satellites was launched into an incorrect, highly eccentric orbital plane with a lower than nominal inclination angle. All Galileo satellites are equipped with satellite laser ranging (SLR) retroreflectors which allow, for example, for the assessment of the orbit quality or for the SLR-GNSS co-location in space. The number of SLR observations to Galileo satellites has been continuously increasing thanks to a series of intensive campaigns devoted to SLR tracking of GNSS satellites initiated by the International Laser Ranging Service. This paper assesses systematic effects and quality of Galileo orbits using SLR data with a main focus on Galileo satellites launched into incorrect orbits. We compare the SLR observations with respect to microwave-based Galileo orbits generated by the Center for Orbit Determination in Europe (CODE) in the framework of the International GNSS Service Multi-GNSS Experiment for the period 2014.0-2016.5. We analyze the SLR signature effect, which is characterized by the dependency of SLR residuals with respect to various incidence angles of laser beams for stations equipped with single-photon and multi-photon detectors. Surprisingly, the CODE orbit quality of satellites in the incorrect orbital planes is not worse than that of nominal FOC and IOV orbits. The RMS of SLR residuals is even lower by 5.0 and 1.5 mm for satellites in the incorrect orbital planes than for FOC and IOV satellites, respectively. The mean SLR offsets equal -44.9, -35.0, and -22.4 mm for IOV, FOC, and satellites in the incorrect orbital plane. Finally, we found that the empirical orbit models, which were originally designed for precise orbit determination of GNSS satellites in circular orbits, provide fully appropriate results also for highly eccentric orbits with variable linear

Feasibility and tradeoff study of an aeromaneuvering orbit-to-orbit shuttle (AMOOS)

NASA Technical Reports Server (NTRS)

White, J.

1974-01-01

This study establishes that configurations satisfying the aeromaneuvering orbit-to-orbit shuttle (AMOOS) requirements can be designed with performance capabilities in excess of the purely propulsive space tug. In view of this improved potential of the AMOOS vehicle over the propulsive space tug concept it is recommended that the AMOOS studies be advanced to a stage comparable to those performed for the space tug. This advancement is needed in particular in areas that are either peculiar to AMOOS or not addressed in sufficient detail in these studies to date. These areas include the thermodynamics problems, navigation and guidance, operations and economics analyses, subsystems and interfaces. The aeromaneuvering orbit-to-orbit shuttle (AMOOS) is evaluated as a candidate reusable third stage to the two-stage earth-to-orbit shuttle (EOS). AMOOS has the potential for increased payload capability over the purely propulsive space tug by trading a savings in consumables for an increase in structural and thermal protection system (TPS) mass.

Lunar Exploration Orbiter (LEO)

NASA Astrophysics Data System (ADS)

Jaumann, R.; Spohn, T.; Hiesinger, H.; Jessberger, E. K.; Neukum, G.; Oberst, J.; Helbert, J.; Christensen, U.; Keller, H. U.; Mall, U.; Böhnhardt, H.; Hartogh, P.; Glassmeier, K.-H.; Auster, H.-U.; Moreira, A.; Werner, M.; Pätzold, M.; Palme, H.; Wimmer-Schweingruber, R.; Mandea, M.; Lesur, V.; Häusler, B.; Hördt, A.; Eichentopf, K.; Hauber, E.; Hoffmann, H.; Köhler, U.; Kührt, E.; Michaelis, H.; Pauer, M.; Sohl, F.; Denk, T.; van Gasselt, S.

2007-08-01

The Moon is an integral part of the Earth-Moon system, it is a witness to more than 4.5 b. y. of solar system history, and it is the only planetary body except Earth for which we have samples from known locations. The Moon is our closest companion and can easily be reached from Earth at any time, even with a relatively modest financial budget. Consequently, the Moon was the first logical step in the exploration of our solar system before we pursued more distant targets such as Mars and beyond. The vast amount of knowledge gained from the Apollo and other lunar missions of the late 1960's and early 1970's demonstrates how valuable the Moon is for the understanding of our planetary system. Even today, the Moon remains an extremely interesting target scientifically and technologically, as ever since, new data have helped to address some of our questions about the Earth-Moon system, many questions remained. Therefore, returning to the Moon is the critical stepping-stone to further exploring our immediate planetary neighborhood. In this concept study, we present scientific and technological arguments for a national German lunar mission, the Lunar Explorations Orbiter (LEO). Numerous space-faring nations have realized and identified the unique opportunities related to lunar exploration and have planned missions to the Moon within the next few years. Among these missions, LEO will be unique, because it will globally explore the Moon in unprecedented spatial and spectral resolution. LEO will significantly improve our understanding of the lunar surface composition, surface ages, mineralogy, physical properties, interior, thermal history, gravity field, regolith structure, and magnetic field. The Lunar Explorations Orbiter will carry an entire suite of innovative, complementary technologies, including high-resolution camera systems, several spectrometers that cover previously unexplored parts of the electromagnetic spectrum over a broad range of wavelengths, microwave and

Introducing Earth's Orbital Eccentricity

ERIC Educational Resources Information Center

Oostra, Benjamin

2015-01-01

Most students know that planetary orbits, including Earth's, are elliptical; that is Kepler's first law, and it is found in many science textbooks. But quite a few are mistaken about the details, thinking that the orbit is very eccentric, or that this effect is somehow responsible for the seasons. In fact, the Earth's orbital eccentricity is…

NASA's Orbital Space Plane Risk Reduction Strategy

NASA Technical Reports Server (NTRS)

Dumbacher, Dan

2003-01-01

This paper documents the transformation of NASA s Space Launch Initiative (SLI) Second Generation Reusable Launch Vehicle Program under the revised Integrated Space Transportation Plan, announced November 2002. Outlining the technology development approach followed by the original SLI, this paper gives insight into the current risk-reduction strategy that will enable confident development of the Nation s first orbital space plane (OSP). The OSP will perform an astronaut and contingency cargo transportation function, with an early crew rescue capability, thus enabling increased crew size and enhanced science operations aboard the International Space Station. The OSP design chosen for full-scale development will take advantage of the latest innovations American industry has to offer. The OSP Program identifies critical technologies that must be advanced to field a safe, reliable, affordable space transportation system for U.S. access to the Station and low-Earth orbit. OSP flight demonstrators will test crew safety features, validate autonomous operations, and mature thermal protection systems. Additional enabling technologies may be identified during the OSP design process as part of an overall risk-management strategy. The OSP Program uses a comprehensive and evolutionary systems acquisition approach, while applying appropriate lessons learned.

SOLARIS: Software for planet formation and orbital integrations

NASA Astrophysics Data System (ADS)

Süli software, Á.

2013-11-01

I present SOLARIS a general purpose software package for doing N-body and planet formation simulations. SOLARIS is capable to (i) to follow the orbital evolution of the solar system's major planets and minor bodies, (ii) to study the dynamics of exoplanetary systems, and (iii) to study the early and later phases of planetary formation. The process to bring bodies with different epochs to one common epoch, i.e. synchronization is implemented. Apart from the Newtonian gravitational forces, aerodynamic drag force, and type I and II migration forces are also implemented. The code also includes a nebula model. To speed up the computation, SOLARIS treats particles with different interaction properties. Several two-body events are monitored, such as collision, ejection etc. Arbitrary chemical composition can be assigned to massive bodies and during collisions the new body's composition is based on the mergers. The input is given in XML to define the parameters in a well-structured and flexible way. SOLARIS is designed to be versatile and easy to use, accepting initial conditions in either Cartesian coordinates or Keplerian orbital elements.

Do Close-in Giant Planets Orbiting Evolved Stars Prefer Eccentric Orbits?

NASA Astrophysics Data System (ADS)

Grunblatt, Samuel K.; Huber, Daniel; Gaidos, Eric; Lopez, Eric D.; Barclay, Thomas; Chontos, Ashley; Sinukoff, Evan; Van Eylen, Vincent; Howard, Andrew W.; Isaacson, Howard T.

2018-07-01

The NASA Kepler and K2 Missions have recently revealed a population of transiting giant planets orbiting moderately evolved, low-luminosity red giant branch stars. Here, we present radial velocity (RV) measurements of three of these systems, revealing significantly non-zero orbital eccentricities in each case. Comparing these systems with the known planet population suggests that close-in giant planets around evolved stars tend to have more eccentric orbits than those around main sequence stars. We interpret this as tentative evidence that the orbits of these planets pass through a transient, moderately eccentric phase where they shrink faster than they circularize due to tides raised on evolved host stars. Additional RV measurements of currently known systems, along with new systems discovered by the recently launched NASA Transiting Exoplanet Survey Satellite (TESS) mission, may constrain the timescale and mass dependence of this process.

Sinus involvement in inflammatory orbital pseudotumor.

PubMed

Eshaghian, J; Anderson, R L

1981-04-01

Orbital pseudotumor is a difficult diagnosis to establish preoperatively. The relationship between sinus disease and orbital pseudotumor is controversial. We describe two patients with unilateral proptosis, diplopia, palpable orbital masses, ocular discomfort, and sinus problems of short duration. Echographically, both had low reflective masses in the orbit and the adjacent sinuses. Roentgenograms and echograms were interpreted as showing erosion of the bony orbital wall. A presumptive diagnosis of sinus malignant neoplasm with orbital extension was made. Sinus histopathologic examination in one case and nasal histopathologic examination in the other showed chronic inflammatory changes compatible with the diagnosis of pseudotumor. At orbitotomy, one patient had vessels communicating between the orbital and sinus lesions, and both patients had irregular pitting of the bone next to the histologically proved orbital pseudotumors. The lytic erosive changes predicted preoperatively were not present. Simultaneous orbital and sinus pseudotumors seem to be a distinct clinicopathologic entity. Those concerned with the diagnosis and management of orbital disease should be aware of this entity.

Paleoecology and Paleoenvironmental Interpretations of the Late Cretaceous Lower Cantwell Formation, Denali National Park, Alaska

NASA Astrophysics Data System (ADS)

Tomsich, C. S.; Salazar Jaramillo, S.; Jacobus, R. T.; McCarthy, P. J.; Fowell, S. J.; Fiorillo, A. R.

2010-12-01

The level of diversity of an ancient high-latitude fauna or flora is of interest not just for the study of species evolution and paleogeographic migration patterns, but also for the imminent response to an amplified climate change rate. Climate modelers thus focus increasingly on proxies of Polar Regions. A rich floral and faunal record indicative of a warm high-latitude paleoclimate is presently emerging from the late Campanian-Maastrichtian lower Cantwell Formation in Denali National Park, south-central Alaska. This thick (up to 4000m) alluvial fan succession was deposited during the latest accretionary phase of the Wrangellia terrane to the former southern margin of Alaska. Facies descriptions from outcrops near Sable Mountain and Polychrome Mountain record heterogeneous and laterally discontinuous lithologies characteristic of alluvial and marginal alluvial fan environments: braided channel, sandy channel, crevasse splay, sheetflood, floodplain, and lacustrine. Trace and plant fossils occur predominantly at lithological boundaries. The vertebrate fossil record encompasses tracks that can be attributed to fishes, pterosaurs, large and small non-avian theropods, birds, hadrosaurs, and ceratopsians. Hadrosaur footprints are abundant and record populations with multiple generations present. The pterosaur tracks constitute the northernmost fossil occurrence for these flying reptiles. Bird traces range from small, shore-wading bird tracks to those of a large crane-like bird. Diverse invertebrate tracks include freshwater bivalve, ostracode and gastropod trails, crayfish burrows, beetle and mole cricket tracks, wood borings and feeding traces on angiosperm leaves. Plant impression fossils represent dicotyledonous angiosperm leaves referable to nymphaealean, menispermoid, platanoid, trochodendroid and higher hamamelid groups; magnoliid seeds; diverse broad-leaved and blade-like monocot leaf fragments; the leafy shoots, leaves, cones, seeds and wood of cupressaceous and

Correlation of nonorthogonality of best hybrid bond orbitals with bond strength of orthogonal orbitals.

PubMed

Pauling, L

1976-02-01

An expression is derived for the bond length of two spd orbitals with maximum values in two directions forming a given bond angle by consideration of the nonorthogonality integral of two best orbitals in these directions. This equation is equivalent to the expression derived by formulating the pair of orthogonal orbitals. Similar expressions are derived for spdf orbitals. Applications are made to icosahedral and cuboctahedral bonds and to the packing of nucleons in atomic nuclei.

Orbital ATK Cygnus CRS-8 Rendzevous, Capture and Installation to the ISS

NASA Image and Video Library

2017-11-14

Orbital ATK’s Cygnus spacecraft arrived at the International Space Station Nov. 14 after a two-day journey following its launch Nov. 12 on the company’s Antares rocket from the Wallops Flight Facility in Virginia. Dubbed the “SS Gene Cernan” after the late Gemini and Apollo astronaut who was the last man to walk on the moon, Cygnus was captured by Expedition 53 Flight Engineer Paolo Nespoli of ESA (the European Space Agency) and Commander Randy Bresnik of NASA using the station’s Canadarm2 robotic arm. Cygnus was loaded with some 3 ½ tons of supplies and science experiments for the Expedition crew members on the unique orbiting laboratory and is scheduled to remain attached to the Unity module until early January.

Congenital orbital teratoma.

PubMed

Aiyub, Shereen; Chan, Wengonn; Szetu, John; Sullivan, Laurence J; Pater, John; Cooper, Peter; Selva, Dinesh

2013-12-01

We present a case of mature congenital orbital teratoma managed with lid-sparing exenteration and dermis fat graft. This is a case report on the management of congenital orbital teratoma. A full-term baby was born in Fiji with prolapsed right globe which was surrounded by a nonpulsatile, cystic mass. Clinical and imaging features were consistent with congenital orbital teratoma. Due to limited surgical expertise, the patient was transferred to Adelaide, Australia for further management. The patient underwent a lid-sparing exenteration with frozen section control of the apical margin. A dermis fat graft from the groin was placed beneath the lid skin to provide volume. Histopathology revealed mature tissues from each of the three germ cell layers which confirmed the diagnosis of mature teratoma. We describe the successful use of demis fat graft in socket reconstruction following lid-sparing exenteration for congenital orbital teratoma.

Congenital orbital teratoma

PubMed Central

Aiyub, Shereen; Chan, Weng Onn; Szetu, John; Sullivan, Laurence J; Pater, John; Cooper, Peter; Selva, Dinesh

2013-01-01

We present a case of mature congenital orbital teratoma managed with lid-sparing exenteration and dermis fat graft. This is a case report on the management of congenital orbital teratoma. A full-term baby was born in Fiji with prolapsed right globe which was surrounded by a nonpulsatile, cystic mass. Clinical and imaging features were consistent with congenital orbital teratoma. Due to limited surgical expertise, the patient was transferred to Adelaide, Australia for further management. The patient underwent a lid-sparing exenteration with frozen section control of the apical margin. A dermis fat graft from the groin was placed beneath the lid skin to provide volume. Histopathology revealed mature tissues from each of the three germ cell layers which confirmed the diagnosis of mature teratoma. We describe the successful use of demis fat graft in socket reconstruction following lid-sparing exenteration for congenital orbital teratoma. PMID:23619505

Orbit Determination of Spacecraft in Earth-Moon L1 and L2 Libration Point Orbits

NASA Technical Reports Server (NTRS)

Woodard, Mark; Cosgrove, Daniel; Morinelli, Patrick; Marchese, Jeff; Owens, Brandon; Folta, David

2011-01-01

The ARTEMIS mission, part of the THEMIS extended mission, is the first to fly spacecraft in the Earth-Moon Lissajous regions. In 2009, two of the five THEMIS spacecraft were redeployed from Earth-centered orbits to arrive in Earth-Moon Lissajous orbits in late 2010. Starting in August 2010, the ARTEMIS P1 spacecraft executed numerous stationkeeping maneuvers, initially maintaining a lunar L2 Lissajous orbit before transitioning into a lunar L1 orbit. The ARTEMIS P2 spacecraft entered a L1 Lissajous orbit in October 2010. In April 2011, both ARTEMIS spacecraft will suspend Lissajous stationkeeping and will be maneuvered into lunar orbits. The success of the ARTEMIS mission has allowed the science team to gather unprecedented magnetospheric measurements in the lunar Lissajous regions. In order to effectively perform lunar Lissajous stationkeeping maneuvers, the ARTEMIS operations team has provided orbit determination solutions with typical accuracies on the order of 0.1 km in position and 0.1 cm/s in velocity. The ARTEMIS team utilizes the Goddard Trajectory Determination System (GTDS), using a batch least squares method, to process range and Doppler tracking measurements from the NASA Deep Space Network (DSN), Berkeley Ground Station (BGS), Merritt Island (MILA) station, and United Space Network (USN). The team has also investigated processing of the same tracking data measurements using the Orbit Determination Tool Kit (ODTK) software, which uses an extended Kalman filter and recursive smoother to estimate the orbit. The orbit determination results from each of these methods will be presented and we will discuss the advantages and disadvantages associated with using each method in the lunar Lissajous regions. Orbit determination accuracy is dependent on both the quality and quantity of tracking measurements, fidelity of the orbit force models, and the estimation techniques used. Prior to Lissajous operations, the team determined the appropriate quantity of tracking