Sample records for ray crater apollo
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Cosmic ray exposure ages of features and events at the Apollo landing sites
International Nuclear Information System (INIS)
Arvidson, R.; Crozaz, G.; Drozd, R.J.; Hohenberg, C.M.; Morgan, C.J.
1975-01-01
Cosmic ray exposure ages of lunar samples have been used to date surface features related to impact cratering and downslope movement of material. Only when multiple samples related to a feature have the same rare gas exposure age, or when a single sample has the same 81 Kr-Kr and track exposure age can a feature be considered reliably dated. Because any single lunar sample is likely to have had a complex history, assignment of ages to features based upon only one determination by any method should be avoided. Based on the above criteria, there are only five well-dated lunar features: Cone Crater (Apollo 14) 26 m.y., North Ray Crater (Apollo 16) 50 m.y., South Ray Crater (Apollo 16) 2 m.y., the emplacement of the Station 6 boulders (Apollo 17) 22 m.y., and the emplacement of the Station 7 boulder (Apollo 17) 28 m.y. Other features are tentatively dated or have limits set on their ages: Bench Crater (Apollo 12) =50 m.y. (Auth.)
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International Nuclear Information System (INIS)
Lindstrom, M.M.
1984-01-01
Lunar breccia 67975 is a feldspathic fragmental breccia from North Ray crater, Apollo 16. It contains clasts of alkali gabbronorite and ultra-KREEPy mafic fragment-laden melt breccias, which are unique among Apollo 16 samples. Both are alkali- and iron-rich rocks with moderate to high REE concentrations. They more strongly resemble Apollo 14 gabbronorites and alkali anorthosites and KREEP-rich rocks than they do other Apollo 16 samples. The other clasts in 67975 are the ferroan anorthosites, feldspathic melt rocks, and magnesian granulites, which are typical of other feldspathic fragmental breccias. Examination of bulk and mineral compositions of other breccias and melt rocks suggests that alkali gabbronorite may be a minor component in other North Ray crater breccias and feldspathic melt rocks. This implies that alkali gabbronorite was a fairly early (4.0 b.y.) crustal component in the North Ray crater region
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Lindstrom, M. M.; Lindstrom, D. J.; Lum, R. K. L.; Schuhmann, P. J.; Nava, D. F.; Schuhmann, S.; Philpotts, J. A.; Winzer, S. R.
1977-01-01
The samples of the White Breccia Boulders obtained during the Apollo 16 mission and investigated in the reported study include an anorthositic breccia (67415), a dark matrix breccia (67435), a light matrix breccia (67455), and a large clast of dark matrix breccia (67475) taken from the 67455 boulder. The chemical analyses of bulk samples of the samples are listed in a table. A graph shows the lithophile trace element abundances. Another graph indicates the variation of Sm with Al2O3 content for samples from the White Breccia Boulders. The North Ray Crater breccias are found to be in general slightly more aluminous than breccias from the other stations at the Apollo 16 site. Analyses of eight Apollo 16 breccias cited in the literature range from 25% to 35% Al2O3. However, the North Ray Crater breccias are more clearly distinct from the other Apollo 16 breccias in their contents of lithophile trace elements.
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Pre-Imbrian craters and basins: ages, compositions and excavation depths of Apollo 16 breccias
International Nuclear Information System (INIS)
Maurer, P.; Eberhardt, P.; Geiss, J.; Groegler, N.; Stettler, A.; Brown, G.M.; Peckett, A.; Kraehenbuehl, U.
1978-01-01
Breccia fragments have been analyzed from the 2 to 4 mm sieve fraction of three Apollo 16 soils collected in the vicinity of North Ray Crater. Ar 39 -Ar 40 ages, Ar 37 -Ar 38 exposure ages, abundances of major and certain trace elements, and petrographic data relevant to thermal history have been obtained for up to 48 individual fragments. Among the samples, 30 gave Ar 39 -Ar 40 release patterns that allowed the assignment of a high- or intermediate-temperature plateau age and the recognition of three age groups. Group 1 (10 fragments) are 4.12 to 4.21 AE, Group 2 (13 fragments) are 3.89 to 4.02 AE, and Group 3 (6 fragments) are 6 y, the age of North Ray Crater. Compositional and textural properties of the three groups are discussed. (U.K.)
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Hiesinger, Harald; Pasckert, Jan Henrik; van der Bogert, Carolyn H.; Robinson, Mark S.
2016-04-01
Accurately determining the lunar cratering chronology is prerequisite for deriving absolute model ages (AMAs) across the lunar surface and throughout the Solar System [e.g., 1]. However, the lunar chronology is only constrained by a few data points over the last 1 Ga and there are no calibration data available between 1 and 3 Ga and beyond 3.9 Ga [2]. Rays from Autolycus and Aristillus cross the Apollo 15 landing site and presumably transported material to this location [3]. [4] proposed that at the Apollo 15 landing site about 32% of any exotic material would come from Autolycus crater and 25% would come from Aristillus crater. [5,6] proposed that the 39Ar-40Ar age of 2.1 Ga derived from three petrologically distinct, shocked Apollo 15 KREEP basalt samples, date Autolycus crater. Grier et al. [7] reported that the optical maturity (OMAT) characteristics of these craters are indistinguishable from the background values despite the fact that both craters exhibit rays that were used to infer relatively young, i.e., Copernican ages [8,9]. Thus, both OMAT characteristics and radiometric ages of 2.1 Ga and 1.29 Ga for Autolycus and Aristillus, respectively, suggest that these two craters are not Copernican in age. [10] interpreted newer U-Pb ages of 1.4 and 1.9 Ga from sample 15405 as the formation ages of Aristillus and Autolycus. If Autolycus is indeed the source of the dated exotic material collected at the Apollo 15 landing site, than performing crater size frequency distribution (CSFD) measurements for Autolycus offers the possibility to add a new calibration point to the lunar chronology, particularly in an age range that was previously unconstrained. We used calibrated and map-projected LRO NAC images to perform CSFD measurements within ArcGIS, using CraterTools [11]. CSFDs were then plotted with CraterStats [12], using the production and chronology functions of [13]. We determined ages of 3.72 and 3.85 Ga for the interior (Ai1) and ejecta area Ae3, which we
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Stratigraphy of the Descartes region /Apollo 16/ - Implications for the origin of samples
Head, J. W.
1974-01-01
Analysis of terrain in the Apollo 16 Descartes landing region shows a series of features that form a stratigraphic sequence which dominates the history and petrogenesis at the site. An ancient 150-km diam crater centered on the Apollo 16 site is one of the earliest recognizable major structures. Nectaris ejecta was concentrated in a regional low at the base of the back slope of the Nectaris basin to form the Descartes Mountains. Subsequently, a 60-km diam crater formed in the Descartes Mountains centered about 25 km to the west of the site. This crater dominates the geology and petrogenetic history of the site. Stone and Smoky Mountains represent the degraded terraced crater walls, and the dark matrix breccias and metaclastic rocks derived from North and South Ray craters represent floor fallback breccias from this cratering event. The interpretation is developed that the stratigraphy of the Cayley and Descartes, and thus the historical record of the Apollo 16 region, documents the complex interaction of deposits and morphology of local and regional impact cratering events. Large local 60- to 150-km diam craters have had a dramatic and previously unrecognized effect on the history and petrology of the Apollo 16 site.
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Fresh Impact Crater and Rays in Tharsis
2002-01-01
The Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) Extended Mission has included dozens of opportunities to point the spacecraft directly at features of interest so that pictures of things not seen during the earlier Mapping Mission can be obtained. The example shown here is a small meteorite impact crater in northern Tharsis near 17.2oN, 113.8oW. Viking Orbiter images from the late 1970's showed at this location what appeared to be a dark patch with dark rays emanating from a brighter center. The MOC team surmised that the dark rays may be indicating the location of afresh crater formed by impact sometime in the past few centuries (since dark ray are quickly covered by dust falling out of the martian atmosphere). All through MOC's Mapping Mission in 1999 and 2000, attempts were made to image the crater as predictions indicated that the spacecraft would pass over the site, but the crater was never seen. Finally, in June 2001, Extended Mission operations allowed the MOC team to point the spacecraft (and hence the camera, which is fixed to the spacecraft)directly at the center of the dark rays, where we expected to find the crater.The picture on the left (above, A) is a mosaic of three MOC high resolution images and one much lower-resolution Viking image. From left to right, the images used in the mosaic are: Viking 1 516A55, MOC E05-01904, MOCM21-00272, and MOC M08-03697. Image E05-01904 is the one taken in June 2001 by pointing the spacecraft. It captured the impact crater responsible for the rays. A close-up of the crater, which is only 130 meters (427 ft)across, is shown on the right (above, B). This crater is only one-tenth the size of the famous Meteor Crater in northern Arizona.The June 2001 MOC image reveals many surprises about this feature. For one, the crater is not located at the center of the bright area from which the dark rays radiate. The rays point to the center of this bright area, not the crater. Further, the dark material ejected from the
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Apollo 16 exploration of Descartes - A geologic summary.
1973-01-01
The Cayley Plains at the Apollo 16 landing site consist of crudely stratified breccias to a depth of at least 200 meters, overlain by a regolith 10 to 15 meters thick. Samples, photographs, and observations by the astronauts indicate that most of the rocks are impact breccias derived from an anorthosite-gabbro complex. The least brecciated members of the suite include coarse-grained anorthosite and finer-grained, more mafic rocks, some with igneous and some with metamorphic textures. Much of the transverse area is covered by ejecta from North Ray and South Ray craters, but the abundance of rock fragments increases to the south toward the younger South Ray crater.
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Mosaic of Apollo 16 Descartes landing site taken from TV transmission
1972-01-01
A 360 degree field of view of the Apollo 16 Descartes landing site area composed of individual scenes taken from a color transmission made by the color RCA TV camera mounted on the Lunar Roving Vehicle. This panorama was made while the LRV was parked at the rim of North Ray crater (Stations 11 and 12) during the third Apollo 16 lunar surface extravehicular activity (EVA-3) by Astronauts John W. Young and Charles M. Duke Jr. The overlay identifies the directions and the key lunar terrain features. The camera panned across the rear portion of the LRV in its 360 degree sweep. Note Young and Duke walking along the edge of the crater in one of the scenes. The TV camera was remotely controlled from a console in the Mission Control Center.
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Inert gas investigations of the Apollo 15 and 17 landing sites
International Nuclear Information System (INIS)
Jordan, J.L.
1975-01-01
The inert gas contents in size fractions of the following fines from the Apollo 15 site: 15071, 15501, 15511, 15421, and 15080 has been determined. In addition, the same for size fractions of fines 79221, 79241, and 79261 from depths of 0 to 2 cm, 2 to 7 cm, and 7 to 17 cm in a trench near Van Serg Crater at the Apollo 17 site was determined. The very low gas contents and lack of anticorrelation with grain diameter of 15421 suggests that these fines are undersaturated with respect to solar wind irradiation. The decrease in slope of the curves for gas concentration vs grain diameter of 15071 for successively heavier gases is interpreted to be the effects of the Rosiwal principle + comminution + agglutinate formation. Evidence for heavily irradiated (with respect to cosmic rays) zones deep within or beneath the regolith exists at both Apollo 15 and 17 landing sites. This may in part explain the ''missing'' cosmic ray record. Scatter between ''young'' and ''old'' age limits in 40 Ar vs 36 Ar plots exists for 15511, and the 3 trench fines from the Apollo 17 landing site. In the case of 15511 the observed ratios suggest that these may be the result of large impacts on the Apennine Front contributing material to the site where 15511 was collected. The observed 40 Ar/ 36 Ar ratios in the trench fines may be the result of excavation of materials with high 40 Ar/ 36 Ar ratios during the Van Serg event. The low apparent 40 K-- 40 Ar ages of the Apollo 15 fines are interpreted to be the result of addition of young 40 K-- 40 Ar age material (less than 1.8 by) from Autolycus and Aristillus, two large craters north of the site, to the older (3.3 by) mare materials
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Cosmic rays score direct hits with Apollo crew
1971-01-01
Apollo 14 astronauts conduted experiments during the spaceflight to help scientists to understand why previous crews have seen flashes of light during missions, believed to be caused by cosmic rays (1 page).
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Apollo 15 clastic materials and their relationship to local geologic features
Fruchter, J. S.; Stoeser, J. W.; Lindstrom, M. M.; Goles, G. G.
1973-01-01
Ninety sub-samples of Apollo 15 materials have been analyzed by instrumental neutron activation analysis techniques for as many as 21 elements. Soil and soil breccia compositions show considerable variation from station to station although at any given station the soils and soil breccias were compositionally very similar to one another. Mixing model calculations show that the station-to-station variations can be related to important local geologic features. These features include the Apennine Front, Hadley Rille and the ray from the craters Aristillus or Autolycus. Compositional similarities between soils and soil breccias at the Apollo 15 site indicate that the breccias and soils are related in some fundamental way, although the exact nature of this relationship is not yet fully understood.
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Radioactivity observed in the sodium iodide gamma-ray spectrometer returned on the Apollo 17 mission
Dyer, C. S.; Trombka, J. I.; Schmadebeck, R. L.; Eller, E.; Bielefeld, M. J.; Okelley, G. D.; Eldridge, J. S.; Northcutt, K. J.; Metzger, A. E.; Reedy, R. C.
1975-01-01
In order to obtain information on radioactive background induced in the Apollo 15 and 16 gamma-ray spectrometers (7 cm x 7 cm NaI) by particle irradiation during spaceflight, and identical detector was flown and returned to earth on the Apollo 17 mission. The induced radioactivity was monitored both internally and externally from one and a half hours after splashdown. When used in conjunction with a computation scheme for estimating induced activation from calculated trapped proton and cosmic-ray fluences, these results show an important contribution resulting from both thermal and energetic neutrons produced in the heavy spacecraft by cosmic-ray interactions.
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Determination of lunar surface ages from crater frequency–size ...
Indian Academy of Sciences (India)
and the images from Apollo missions have been calibrated from the lunar soil samples from Apollo and Luna landing sites (Head 1976; Neukum et al. 1975). ... Table 1 shows the ages as derived for the craters with errors. Mare Humorum is believed to be made up of six ring structures of 210, 340, 425, 570 and 1195km.
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SMALL CRATERS AND THEIR DIAGNOSTIC POTENTIAL
Directory of Open Access Journals (Sweden)
R. Bugiolacchi
2017-07-01
Full Text Available I analysed and compared the size-frequency distributions of craters in the Apollo 17 landing region, comprising of six mare terrains with varying morphologies and cratering characteristics, along with three other regions allegedly affected by the same secondary event (Tycho secondary surge. I propose that for the smaller crater sizes (in this work 9–30 m, a] an exponential curve of power −0.18D can approximate Nkm−2 crater densities in a regime of equilibrium, while b] a power function D−3 closely describes the factorised representation of craters by size (1 m. The saturation level within the Central Area suggests that c] either the modelled rates of crater erosion on the Moon should be revised, or that the Tycho event occurred much earlier in time than the current estimate. We propose that d] the size-frequency distribution of small secondary craters may bear the signature (in terms of size-frequency distribution of debris/surge of the source impact and that this observation should be tested further.
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Oblique view of crater Theophilus at northwest edge of Sea of Nectar
1969-01-01
An Apollo 11 oblique view of the large crater Theophilus located at the northwest edge of the Sea of Nectar on the lunar nearside. Theophilus is about 60 statute miles in diameter. the smooth area is Mare Nectaris. The smaller crater Madler, about 14 statute miles in diameter, is located to the east of Theophilus. Visible in the background are the large crater Fracastorius and the smaller crater Beaumont. The coordinates of the center of this photograph are 29 degrees east longitude and 11 degrees south latitude.
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Nevada Test Site craters used for astronaut training
Moore, H. J.
1977-01-01
Craters produced by chemical and nuclear explosives at the Nevada Test Site were used to train astronauts before their lunar missions. The craters have characteristics suitable for reconnaissance-type field investigations. The Schooner test produced a crater about 300 m across and excavated more than 72 m of stratigraphic section deposited in a fairly regular fashion so that systematic observations yield systematic results. Other features common on the moon, such as secondary craters and glass-coated rocks, are present at Schooner crater. Smaller explosive tests on Buckboard Mesa excavated rocks from three horizontal alteration zones within basalt flows so that the original sequence of the zones could be determined. One crater illustrated the characteristics of craters formed across vertical boundaries between rock units. Although the exercises at the Nevada Test Site were only a small part of the training of the astronauts, voice transcripts of Apollo missions 14, 16, and 17 show that the exercises contributed to astronaut performance on the moon.
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Photogrammetry using Apollo 16 orbital photography, part B
Wu, S. S. C.; Schafer, F. J.; Jordan, R.; Nakata, G. M.
1972-01-01
Discussion is made of the Apollo 15 and 16 metric and panoramic cameras which provided photographs for accurate topographic portrayal of the lunar surface using photogrammetric methods. Nine stereoscopic models of Apollo 16 metric photographs and three models of panoramic photographs were evaluated photogrammetrically in support of the Apollo 16 geologic investigations. Four of the models were used to collect profile data for crater morphology studies; three models were used to collect evaluation data for the frequency distributions of lunar slopes; one model was used to prepare a map of the Apollo 16 traverse area; and one model was used to determine elevations of the Cayley Formation. The remaining three models were used to test photogrammetric techniques using oblique metric and panoramic camera photographs. Two preliminary contour maps were compiled and a high-oblique metric photograph was rectified.
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Brown, Richard B.; Navard, Andrew R.; Holland, Donald E.; McKellip, Rodney D.; Brannon, David P.
2010-01-01
Barringer Meteorite Crater or Meteor Crater, AZ, has been a site of high interest for lunar and Mars analog crater and terrain studies since the early days of the Apollo-Saturn program. It continues to be a site of exceptional interest to lunar, Mars, and other planetary crater and impact analog studies because of its relatively young age (est. 50 thousand years) and well-preserved structure. High resolution (2 meter to 1 decimeter) digital terrain models of Meteor Crater in whole or in part were created at NASA Stennis Space Center to support several lunar surface analog modeling activities using photogrammetric and ground based laser scanning techniques. The dataset created by this activity provides new and highly accurate 3D models of the inside slope of the crater as well as the downslope rock distribution of the western ejecta field. The data are presented to the science community for possible use in furthering studies of Meteor Crater and impact craters in general as well as its current near term lunar exploration use in providing a beneficial test model for lunar surface analog modeling and surface operation studies.
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The apollo 15 lunar samples: A preliminary description
Gast, P.W.; Phinney, W.C.; Duke, M.B.; Silver, L.T.; Hubbard, N.J.; Heiken, G.H.; Butler, P.; McKay, D.S.; Warner, J.L.; Morrison, D.A.; Horz, F.; Head, J.; Lofgren, G.E.; Ridley, W.I.; Reid, A.M.; Wilshire, H.; Lindsay, J.F.; Carrier, W.D.; Jakes, P.; Bass, M.N.; Brett, P.R.; Jackson, E.D.; Rhodes, J.M.; Bansal, B.M.; Wainwright, J.E.; Parker, K.A.; Rodgers, K.V.; Keith, J.E.; Clark, R.S.; Schonfeld, E.; Bennett, L.; Robbins, Martha M.; Portenier, W.; Bogard, D.D.; Hart, W.R.; Hirsch, W.C.; Wilkin, R.B.; Gibson, E.K.; Moore, C.B.; Lewis, C.F.
1972-01-01
Samples returned from the Apollo 15 site consist of mare basalts and breccias with a variety of premare igneous rocks. The mare basalts are from at least two different lava flows. The bulk chemical compositions and textures of these rocks confirm the previous conclusion that the lunar maria consist of a series of extrusive volcanic rocks that are rich in iron and poor in sodium. The breccias contain abundant clasts of anorthositic fragments along with clasts of basaltic rocks much richer in plagioclase than the mare basalts. These two rock types also occur as common components in soil samples from this site. The rocks and soils from both the front and mare region exhibit a variety of shock characteristics that can best be ascribed to ray material from the craters Aristillus or Autolycus.
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Experience of modeling relief of impact lunar crater Aitken based on high-resolution orbital images
Mukhametshin, Ch R.; Semenov, A. A.; Shpekin, M. I.
2018-05-01
The paper presents the author’s results of modeling the relief of lunar Aitken crater on the basis of high-resolution orbital images. The images were taken in the frame of the “Apollo” program in 1971-1972 and delivered to the Earth by crews of “Apollo-15” and “Apollo-17”. The authors used the images obtained by metric and panoramic cameras. The main result is the careful study of the unusual features of Aitken crater on models created by the authors with the computer program, developed by “Agisoft Photoscan”. The paper shows what possibilities are opened with 3D models in the study of the structure of impact craters on the Moon. In particular, for the first time, the authors managed to show the structure of the glacier-like tongue in Aitken crater, which is regarded as one of the promising areas of the Moon for the forthcoming expeditions.
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Compositional characteristics of some Apollo 14 clastic materials.
Lindstrom, M. M.; Duncan, A. R.; Fruchter, J. S.; Mckay, S. M.; Stoeser, J. W.; Goles, G. G.; Lindstrom, D. J.
1972-01-01
Eighty-two subsamples of Apollo 14 materials have been analyzed by instrumental neutron activation analysis techniques for as many as 25 elements. In many cases, it was necessary to develop new procedures to allow analyses of small specimens. Compositional relationships among Apollo 14 materials indicate that there are small but systematic differences between regolith from the valley terrain and that from Cone Crater ejecta. Fragments from 1-2 mm size fractions of regolith samples may be divided into compositional classes, and the 'soil breccias' among them are very similar to valley soils. Multicomponent linear mixing models have been used as interpretive tools in dealing with data on regolith fractions and subsamples from breccia 14321. These mixing models show systematic compositional variations with inferred age for Apollo 14 clastic materials.
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Blocky craters: implications about the lunar megaregolith
International Nuclear Information System (INIS)
Thompson, T.W.; Roberts, W.J.; Hartmann, W.K.; Shorthill, R.W.; Zisk, S.H.
1979-01-01
Radar, infrared, and photogeologic properties of lunar craters have been studied to determine whether there is a systematic difference in blocky craters between the maria and terrae and whether this difference may be due to a deep megaregolith of pulverized material forming the terra surface, as opposed to a layer of semi-coherent basalt flows forming the mare surface. Some 1310 craters from about 4 to 100 km diameter have been catalogued as radar and/or infrared anomalies. In addition, a study of Apollo Orbital Photography confirmed that the radar and infrared anomalies are correlated with blocky rubble around the crater. Analysis of the radar and infrared data indicated systematic terra-mare differences. Fresh terra craters smaller than 12 km were less likely to be infrared and radar anomalies than comparable mare craters: but terra and mare craters larger than 12 km had similar infrared and radar signatures. Also, there are many terra craters which are radar bright but not infrared anomalies. The authors interpretation of these data is that while the maria are rock layers (basaltic flow units) where craters eject boulder fields, the terrae are covered by relatively pulverized megaregolith at least 2 km deep, where craters eject less rocky rubble. Blocky rubble, either in the form of actual rocks or partly consolidated blocks, contributes to the radar and infrared signatures of the crater. However, aging by impacts rapidly destroys these effects, possibly through burial by secondary debris or by disintegration of the blocks themselves, especially in terra regions. (Auth.)
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Spence, H. E.; Case, A. W.; Golightly, M. J.; Heine, T.; Larsen, B. A.; Blake, J. B.; Caranza, P.; Crain, W. R.; George, J.; Lalic, M.; Lin, A.; Looper, M. D.; Mazur, J. E.; Salvaggio, D.; Kasper, J. C.
2009-01-01
The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter (LRO) characterizes the radiation environment to be experienced by humans during future lunar missions. CRaTER measures the effects of ionizing energy loss in matter due to penetrating solar energetic protons (SEP) and galactic cosmic rays (GCR), specifically in silicon solid-state detectors and after interactions with tissue-equivalent plastic (TEP), a synthetic analog of human tissue. The CRaT...
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Galmed, A. H.; du Plessis, A.; le Roux, S. G.; Hartnick, E.; Von Bergmann, H.; Maaza, M.
2018-01-01
Laboratory X-ray computed tomography is an emerging technology for the 3D characterization and dimensional analysis of many types of materials. In this work we demonstrate the usefulness of this characterization method for the full three dimensional analysis of laser ablation craters, in the context of a laser induced breakdown spectroscopy setup. Laser induced breakdown spectroscopy relies on laser ablation for sampling the material of interest. We demonstrate here qualitatively (in images) and quantitatively (in terms of crater cone angles, depths, diameters and volume) laser ablation crater analysis in 3D for metal (aluminum) and rock (false gold ore). We show the effect of a Gaussian beam profile on the resulting crater geometry, as well as the first visual evidence of undercutting in the rock sample, most likely due to ejection of relatively large grains. The method holds promise for optimization of laser ablation setups especially for laser induced breakdown spectroscopy.
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Apollo-Soyuz Pamphlet No. 2: X-Rays, Gamma-Rays. Apollo-Soyuz Experiments in Space.
Page, Lou Williams; Page, Thornton
This booklet is the second in a series of nine that describe the Apollo-Soyuz mission and experiments. This set is designed as a curriculum supplement for high school and college teachers, supervisors, curriculum specialists, textbook writers, and the general public. These booklets provide sources of ideas, examples of the scientific method,…
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Apollo 17 'melt sheet': chemistry, age and Rb/Sr systematics
Energy Technology Data Exchange (ETDEWEB)
Winzer, S R [Martin Marietta Labs., Baltimore, Md. (USA); Nava, D F; Schuhmann, S; Philpotts, J A [National Aeronautics and Space Administration, Greenbelt, Md. (USA). Goddard Space Flight Center; Schuhmann, P J; Lum, R K.L.; Lindstrom, M M; Lindstrom, D J [Maryland Univ., College Park (USA)
1977-01-01
Major, minor and trace element compositions, age data and Rb/Sr systematics of Apollo 17 boulders have been compiled, and additional analyses performed on a norite breccia clast (77215) included in the Apollo 17, Station 7 boulder. The Apollo 17 boulders are found to be identical or nearly so in major, minor and trace element composition, suggesting that they all originated as an impact melt analogous to melt sheets found in larger terrestrial craters. The matrix dates (/sup 40/Ar//sup 39/Ar) and Rb/Sr systematics available suggest that this impact melt formed by a single impact about 4 b.y. ago. This impact excavated, shocked, brecciated and melted norites, norite cumulates and possibly anorthositic gabbros and dunites about 4.4 b.y. old. The impact was likely a major one, possibly the Serenitatis basin-forming event.
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X-ray Diffraction Results from Mars Science Laboratory: Mineralogy of Rocknest at Gale Crater
Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Chipera, S. J.; Morris, R. V.; Ming, D. W.; Treiman, A. H.; Sarrazin, P.; Morrison, S. M.; Downs, R. T.; Achilles, C. N.; Yen, A. S.; Bristow, T. F.; Crisp, J. A.; Morookian, J. M.; Farmer, J. D.; Rampe, E. B.; Stolper, E. M.; Spanovich, N.; Achilles, Cherie; Agard, Christophe; Verdasca, José Alexandre Alves; Anderson, Robert; Anderson, Ryan; Archer, Doug; Armiens-Aparicio, Carlos; Arvidson, Ray; Atlaskin, Evgeny; Atreya, Sushil; Aubrey, Andrew; Baker, Burt; Baker, Michael; Balic-Zunic, Tonci; Baratoux, David; Baroukh, Julien; Barraclough, Bruce; Bean, Keri; Beegle, Luther; Behar, Alberto; Bell, James; Bender, Steve; Benna, Mehdi; Bentz, Jennifer; Berger, Gilles; Berger, Jeff; Berman, Daniel; Bish, David; Blake, David F.; Avalos, Juan J. Blanco; Blaney, Diana; Blank, Jen; Blau, Hannah; Bleacher, Lora; Boehm, Eckart; Botta, Oliver; Böttcher, Stephan; Boucher, Thomas; Bower, Hannah; Boyd, Nick; Boynton, Bill; Breves, Elly; Bridges, John; Bridges, Nathan; Brinckerhoff, William; Brinza, David; Bristow, Thomas; Brunet, Claude; Brunner, Anna; Brunner, Will; Buch, Arnaud; Bullock, Mark; Burmeister, Sönke; Cabane, Michel; Calef, Fred; Cameron, James; Campbell, John "Iain"; Cantor, Bruce; Caplinger, Michael; Rodríguez, Javier Caride; Carmosino, Marco; Blázquez, Isaías Carrasco; Charpentier, Antoine; Chipera, Steve; Choi, David; Clark, Benton; Clegg, Sam; Cleghorn, Timothy; Cloutis, Ed; Cody, George; Coll, Patrice; Conrad, Pamela; Coscia, David; Cousin, Agnès; Cremers, David; Crisp, Joy; Cros, Alain; Cucinotta, Frank; d'Uston, Claude; Davis, Scott; Day, Mackenzie "Kenzie"; Juarez, Manuel de la Torre; DeFlores, Lauren; DeLapp, Dorothea; DeMarines, Julia; DesMarais, David; Dietrich, William; Dingler, Robert; Donny, Christophe; Downs, Bob; Drake, Darrell; Dromart, Gilles; Dupont, Audrey; Duston, Brian; Dworkin, Jason; Dyar, M. Darby; Edgar, Lauren; Edgett, Kenneth; Edwards, Christopher; Edwards, Laurence; Ehlmann, Bethany; Ehresmann, Bent; Eigenbrode, Jen; Elliott, Beverley; Elliott, Harvey; Ewing, Ryan; Fabre, Cécile; Fairén, Alberto; Farley, Ken; Farmer, Jack; Fassett, Caleb; Favot, Laurent; Fay, Donald; Fedosov, Fedor; Feldman, Jason; Feldman, Sabrina; Fisk, Marty; Fitzgibbon, Mike; Flesch, Greg; Floyd, Melissa; Flückiger, Lorenzo; Forni, Olivier; Fraeman, Abby; Francis, Raymond; François, Pascaline; Franz, Heather; Freissinet, Caroline; French, Katherine Louise; Frydenvang, Jens; Gaboriaud, Alain; Gailhanou, Marc; Garvin, James; Gasnault, Olivier; Geffroy, Claude; Gellert, Ralf; Genzer, Maria; Glavin, Daniel; Godber, Austin; Goesmann, Fred; Goetz, Walter; Golovin, Dmitry; Gómez, Felipe Gómez; Gómez-Elvira, Javier; Gondet, Brigitte; Gordon, Suzanne; Gorevan, Stephen; Grant, John; Griffes, Jennifer; Grinspoon, David; Grotzinger, John; Guillemot, Philippe; Guo, Jingnan; Gupta, Sanjeev; Guzewich, Scott; Haberle, Robert; Halleaux, Douglas; Hallet, Bernard; Hamilton, Vicky; Hardgrove, Craig; Harker, David; Harpold, Daniel; Harri, Ari-Matti; Harshman, Karl; Hassler, Donald; Haukka, Harri; Hayes, Alex; Herkenhoff, Ken; Herrera, Paul; Hettrich, Sebastian; Heydari, Ezat; Hipkin, Victoria; Hoehler, Tori; Hollingsworth, Jeff; Hudgins, Judy; Huntress, Wesley; Hurowitz, Joel; Hviid, Stubbe; Iagnemma, Karl; Indyk, Steve; Israël, Guy; Jackson, Ryan; Jacob, Samantha; Jakosky, Bruce; Jensen, Elsa; Jensen, Jaqueline Kløvgaard; Johnson, Jeffrey; Johnson, Micah; Johnstone, Steve; Jones, Andrea; Jones, John; Joseph, Jonathan; Jun, Insoo; Kah, Linda; Kahanpää, Henrik; Kahre, Melinda; Karpushkina, Natalya; Kasprzak, Wayne; Kauhanen, Janne; Keely, Leslie; Kemppinen, Osku; Keymeulen, Didier; Kim, Myung-Hee; Kinch, Kjartan; King, Penny; Kirkland, Laurel; Kocurek, Gary; Koefoed, Asmus; Köhler, Jan; Kortmann, Onno; Kozyrev, Alexander; Krezoski, Jill; Krysak, Daniel; Kuzmin, Ruslan; Lacour, Jean Luc; Lafaille, Vivian; Langevin, Yves; Lanza, Nina; Lasue, Jeremie; Le Mouélic, Stéphane; Lee, Ella Mae; Lee, Qiu-Mei; Lees, David; Lefavor, Matthew; Lemmon, Mark; Malvitte, Alain Lepinette; Leshin, Laurie; Léveillé, Richard; Lewin-Carpintier, Éric; Lewis, Kevin; Li, Shuai; Lipkaman, Leslie; Little, Cynthia; Litvak, Maxim; Lorigny, Eric; Lugmair, Guenter; Lundberg, Angela; Lyness, Eric; Madsen, Morten; Mahaffy, Paul; Maki, Justin; Malakhov, Alexey; Malespin, Charles; Malin, Michael; Mangold, Nicolas; Manhes, Gérard; Manning, Heidi; Marchand, Geneviève; Jiménez, Mercedes Marín; García, César Martín; Martin, Dave; Martin, Mildred; Martínez-Frías, Jesús; Martín-Soler, Javier; Martín-Torres, F. Javier; Mauchien, Patrick; Maurice, Sylvestre; McAdam, Amy; McCartney, Elaina; McConnochie, Timothy; McCullough, Emily; McEwan, Ian; McKay, Christopher; McLennan, Scott; McNair, Sean; Melikechi, Noureddine; Meslin, Pierre-Yves; Meyer, Michael; Mezzacappa, Alissa; Miller, Hayden; Miller, Kristen; Milliken, Ralph; Ming, Douglas; Minitti, Michelle; Mischna, Michael; Mitrofanov, Igor; Moersch, Jeff; Mokrousov, Maxim; Jurado, Antonio Molina; Moores, John; Mora-Sotomayor, Luis; Morookian, John Michael; Morris, Richard; Morrison, Shaunna; Mueller-Mellin, Reinhold; Muller, Jan-Peter; Caro, Guillermo Muñoz; Nachon, Marion; López, Sara Navarro; Navarro-González, Rafael; Nealson, Kenneth; Nefian, Ara; Nelson, Tony; Newcombe, Megan; Newman, Claire; Newsom, Horton; Nikiforov, Sergey; Niles, Paul; Nixon, Brian; Dobrea, Eldar Noe; Nolan, Thomas; Oehler, Dorothy; Ollila, Ann; Olson, Timothy; Owen, Tobias; Hernández, Miguel Ángel de Pablo; Paillet, Alexis; Pallier, Etienne; Palucis, Marisa; Parker, Timothy; Parot, Yann; Patel, Kiran; Paton, Mark; Paulsen, Gale; Pavlov, Alex; Pavri, Betina; Peinado-González, Verónica; Pepin, Robert; Peret, Laurent; Perez, Rene; Perrett, Glynis; Peterson, Joe; Pilorget, Cedric; Pinet, Patrick; Pla-García, Jorge; Plante, Ianik; Poitrasson, Franck; Polkko, Jouni; Popa, Radu; Posiolova, Liliya; Posner, Arik; Pradler, Irina; Prats, Benito; Prokhorov, Vasily; Purdy, Sharon Wilson; Raaen, Eric; Radziemski, Leon; Rafkin, Scot; Ramos, Miguel; Rampe, Elizabeth; Raulin, François; Ravine, Michael; Reitz, Günther; Rennó, Nilton; Rice, Melissa; Richardson, Mark; Robert, François; Robertson, Kevin; Manfredi, José Antonio Rodriguez; Romeral-Planelló, Julio J.; Rowland, Scott; Rubin, David; Saccoccio, Muriel; Salamon, Andrew; Sandoval, Jennifer; Sanin, Anton; Fuentes, Sara Alejandra Sans; Saper, Lee; Sarrazin, Philippe; Sautter, Violaine; Savijärvi, Hannu; Schieber, Juergen; Schmidt, Mariek; Schmidt, Walter; Scholes, Daniel "Dan"; Schoppers, Marcel; Schröder, Susanne; Schwenzer, Susanne; Martinez, Eduardo Sebastian; Sengstacken, Aaron; Shterts, Ruslan; Siebach, Kirsten; Siili, Tero; Simmonds, Jeff; Sirven, Jean-Baptiste; Slavney, Susie; Sletten, Ronald; Smith, Michael; Sánchez, Pablo Sobrón; Spanovich, Nicole; Spray, John; Squyres, Steven; Stack, Katie; Stalport, Fabien; Steele, Andrew; Stein, Thomas; Stern, Jennifer; Stewart, Noel; Stipp, Susan Louise Svane; Stoiber, Kevin; Stolper, Ed; Sucharski, Bob; Sullivan, Rob; Summons, Roger; Sumner, Dawn; Sun, Vivian; Supulver, Kimberley; Sutter, Brad; Szopa, Cyril; Tan, Florence; Tate, Christopher; Teinturier, Samuel; ten Kate, Inge; Thomas, Peter; Thompson, Lucy; Tokar, Robert; Toplis, Mike; Redondo, Josefina Torres; Trainer, Melissa; Treiman, Allan; Tretyakov, Vladislav; Urqui-O'Callaghan, Roser; Van Beek, Jason; Van Beek, Tessa; VanBommel, Scott; Vaniman, David; Varenikov, Alexey; Vasavada, Ashwin; Vasconcelos, Paulo; Vicenzi, Edward; Vostrukhin, Andrey; Voytek, Mary; Wadhwa, Meenakshi; Ward, Jennifer; Webster, Chris; Weigle, Eddie; Wellington, Danika; Westall, Frances; Wiens, Roger Craig; Wilhelm, Mary Beth; Williams, Amy; Williams, Joshua; Williams, Rebecca; Williams, Richard B. "Mouser"; Wilson, Mike; Wimmer-Schweingruber, Robert; Wolff, Mike; Wong, Mike; Wray, James; Wu, Megan; Yana, Charles; Yen, Albert; Yingst, Aileen; Zeitlin, Cary; Zimdar, Robert; Mier, María-Paz Zorzano
2013-09-01
The Mars Science Laboratory rover Curiosity scooped samples of soil from the Rocknest aeolian bedform in Gale crater. Analysis of the soil with the Chemistry and Mineralogy (CheMin) x-ray diffraction (XRD) instrument revealed plagioclase (~An57), forsteritic olivine (~Fo62), augite, and pigeonite, with minor K-feldspar, magnetite, quartz, anhydrite, hematite, and ilmenite. The minor phases are present at, or near, detection limits. The soil also contains 27 ± 14 weight percent x-ray amorphous material, likely containing multiple Fe3+- and volatile-bearing phases, including possibly a substance resembling hisingerite. The crystalline component is similar to the normative mineralogy of certain basaltic rocks from Gusev crater on Mars and of martian basaltic meteorites. The amorphous component is similar to that found on Earth in places such as soils on the Mauna Kea volcano, Hawaii.
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The Apollo 17 'melt sheet': chemistry, age and Rb/Sr systematics
International Nuclear Information System (INIS)
Winzer, S.R.; Nava, D.F.; Schuhmann, S.; Philpotts, J.A.
1977-01-01
Major, minor and trace element compositions, age data and Rb/Sr systematics of Apollo 17 boulders have been compiled, and additional analyses performed on a norite breccia clast (77215) included in the Apollo 17, Station 7 boulder. The Apollo 17 boulders are found to be identical or nearly so in major, minor and trace element composition, suggesting that they all originated as an impact melt analogous to melt sheets found in larger terrestrial craters. The matrix dates ( 40 Ar/ 39 Ar) and Rb/Sr systematics available suggest that this impact melt formed by a single impact about 4 b.y. ago. This impact excavated, shocked, brecciated and melted norites, norite cumulates and possibly anorthositic gabbros and dunites about 4.4 b.y. old. The impact was likely a major one, possibly the Serenitatis basin-forming event. (Auth.)
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X-Ray Micro-Computed Tomography of Apollo Samples as a Curation Technique Enabling Better Research
Ziegler, R. A.; Almeida, N. V.; Sykes, D.; Smith, C. L.
2014-01-01
X-ray micro-computed tomography (micro-CT) is a technique that has been used to research meteorites for some time and many others], and recently it is becoming a more common tool for the curation of meteorites and Apollo samples. Micro-CT is ideally suited to the characterization of astromaterials in the curation process as it can provide textural and compositional information at a small spatial resolution rapidly, nondestructively, and without compromising the cleanliness of the samples (e.g., samples can be scanned sealed in Teflon bags). This data can then inform scientists and curators when making and processing future sample requests for meteorites and Apollo samples. Here we present some preliminary results on micro-CT scans of four Apollo regolith breccias. Methods: Portions of four Apollo samples were used in this study: 14321, 15205, 15405, and 60639. All samples were 8-10 cm in their longest dimension and approximately equant. These samples were micro-CT scanned on the Nikon HMXST 225 System at the Natural History Museum in London. Scans were made at 205-220 kV, 135-160 microamps beam current, with an effective voxel size of 21-44 microns. Results: Initial examination of the data identify a variety of mineral clasts (including sub-voxel FeNi metal grains) and lithic clasts within the regolith breccias. Textural information within some of the lithic clasts was also discernable. Of particular interest was a large basalt clast (approx.1.3 cc) found within sample 60639, which appears to have a sub-ophitic texture. Additionally, internal void space, e.g., fractures and voids, is readily identifiable. Discussion: It is clear from the preliminary data that micro-CT analyses are able to identify important "new" clasts within the Apollo breccias, and better characterize previously described clasts or igneous samples. For example, the 60639 basalt clast was previously believed to be quite small based on its approx.0.5 sq cm exposure on the surface of the main mass
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Project M: Scale Model of Lunar Landing Site of Apollo 17
O'Brien, Hollie; Crain, Timothy P.
2010-01-01
The basis of the project was creating a scale model representation of the Apollo 17 lunar landing site. Vital components included surface slope characteristics, crater sizes and locations, prominent rocks, and lighting conditions. The model was made for Project M support when evaluating approach and terminal descent as well as when planning surface operations with respect to the terrain. The project had five main mi lestones during the length of the project. The first was examining the best method to use to re-create the Apollo 17 landing site and then reviewing research fmdings with Dr. Tim Crain and EO staff which occurred on June 25, 2010 at a meeting. The second step was formulating a construction plan, budget, and schedule and then presenting the plan for authority to proceed which occurred on July 6,2010. The third part was building a prototype to test materials and building processes which were completed by July 13, 2010. Next was assembling the landing site model and presenting a mid-term construction status report on July 29, 2010. The fifth and final milestone was demonstrating the model and presenting an exit pitch which happened on August 4, 2010. The project was very technical: it needed a lot of research about moon topography, lighting conditions and angles of the sun on the moon, Apollo 17, and Autonomous Landing and Hazard Avoidance Technology (ALHAT), before starting the actual building process. This required using Spreadsheets, searching internet sources and conducting personal meetings with project representatives. This information assisted the interns in deciding the scale of the model with respect to cracks, craters and rocks and their relative sizes as the objects mentioned could interfere with any of the Lunar Landers: Apollo, Project M and future Landers. The project concluded with the completion of a three dimensional scale model of the Apollo 17 Lunar landing site. This model assists Project M members because they can now visualize
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Basu, A.; Mckay, D. S.
1984-01-01
Petrologic aspects of the Cayley and Descartes formations are reviewed in the light of new data on Apollo 16 soils. Specific comparison of the modal abundances of lithic fragments in drive tube sample 64001/2 from the slopes of Stone Mountain (station 4) and in soil 67941 from the North Ray Crater rim (station 11) shows that melt rocks, especially poikilitic rocks, are more abundant at station 4 than at station 11; the reverse is true for fragmental breccias. Such lithologic differences suggest that stations 4 and 11 do not belong to the same geologic formation. Metamorphosed breccias are pervasive in both the formations and may represent a local component that has been reworked and diluted as fresh materials were added. Lithologic compositions inferred from the study of soil samples are different from lithologic compositions inferred from the study of rake samples or breccia clasts. This difference may be related to a mixing of material of different grain size distributions. The petrology of soils at the Apollo 16 site may not accurately reflect original material associated with either the Descartes or the Cayley formation because of extensive mixing with local material.
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Meteor Crater (Barringer Meteorite Crater), Arizona: Summary of Impact Conditions
Roddy, D. J.; Shoemaker, E. M.
1995-09-01
Meteor Crater in northern Arizona represents the most abundant type of impact feature in our Solar System, i.e., the simple bowl-shaped crater. Excellent exposures and preservation of this large crater and its ejecta blanket have made it a critical data set in both terrestrial and planetary cratering research. Recognition of the value of the crater was initiated in the early 1900's by Daniel Moreau Barringer, whose 27 years of exploration championed its impact origin [1]. In 1960, Shoemaker presented information that conclusively demonstrated that Meteor Crater was formed by hypervelocity impact [2]. This led the U.S. Geological Survey to use the crater extensively in the 1960-70's as a prime training site for the Apollo astronauts. Today, Meteor Crater continues to serve as an important research site for the international science community, as well as an educational site for over 300,000 visitors per year. Since the late 1950's, studies of this crater have presented an increasingly clearer view of this impact and its effects and have provided an improved view of impact cratering in general. To expand on this data set, we are preparing an upgraded summary on the Meteor Crater event following the format in [3], including information and interpretations on: 1) Inferred origin and age of the impacting body, 2) Inferred ablation and deceleration history in Earth's atmosphere, 3) Estimated speed, trajectory, angle of impact, and bow shock conditions, 4) Estimated coherence, density, size, and mass of impacting body, 5) Composition of impacting body (Canyon Diablo meteorite), 6) Estimated kinetic energy coupled to target rocks and atmosphere, 7) Terrain conditions at time of impact and age of impact, 8) Estimated impact dynamics, such as pressures in air, meteorite, and rocks, 9) Inferred and estimated material partitioning into vapor, melt, and fragments, 10) Crater and near-field ejecta parameters, 11) Rock unit distributions in ejecta blanket, 12) Estimated far
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Stratigraphy and depositional history of the Apollo 17 drill core
Taylor, G. J.; Warner, R. D.; Keil, K.
1979-01-01
Lithologic abundances obtained from modal analyses of a continuous string of polished thin sections indicate that the Apollo 17 deep drill core can be divided into three main zones: An upper zone (0-19 cm depth) characterized by high abundances of agglutinates (30%) and a high ratio of mare to non-mare lithic fragments (less than 0.8); a coarse-grained layer (24-56 cm) rich in fragments of high-Ti mare basalts and mineral fragments derived from them, and poor in agglutinates (6%); and a lower zone (56-285 cm) characterized by variable but generally high agglutinate abundances (25%) and a low ratio of mare to nonmare lithic fragments (0.6). Using observations of the geology of the landing site, the principles of cratering dynamics, and the vast amount of data collected on the core, the following depositional history for the section of regolith sampled by the Apollo 17 drill core: was devised.
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Complex Indigenous Organic Matter Embedded in Apollo 17 Volcanic Black Glass Surface Deposits
Thomas-Keprta, Kathie L.; Clemett, S. J.; Ross, D. K.; Le, L.; Rahman, Z.; Gonzalez, C.; McKay, D. S.; Gibson, E. K.
2013-01-01
Papers presented at the first Lunar Science Conference [1] and those published in the subsequent Science Moon Issue [2] reported the C content of Apollo II soils, breccias, and igneous rocks as rang-ing from approx.50 to 250 parts per million (ppm). Later Fegley & Swindle [3] summarized the C content of bulk soils from all the Apollo missions as ranging from 2.5 (Apollo 15) to 280 ppm (Apollo 16) with an overall average of 124+/- 45 ppm. These values are unexpectedly low given that multiple processes should have contributed (and in some cases continue to contribute) to the lunar C inventory. These include exogenous accretion of cometary and asteroidal dust, solar wind implantation, and synthesis of C-bearing species during early lunar volcanism. We estimate the contribution of C from exogenous sources alone is approx.500 ppm, which is approx.4x greater than the reported average. While the assessm ent of indigenous organic matter (OM) in returned lunar samples was one of the primary scientific goals of the Apollo program, extensive analysis of Apollo samples yielded no evidence of any significant indigenous organic species. Furthermore, with such low concentrations of OM reported, the importance of discriminating indigenous OM from terrestrial contamination (e.g., lunar module exhaust, sample processing and handling) became a formidable task. After more than 40 years, with the exception of CH4 [5-7], the presence of indigenous lunar organics still remains a subject of considerable debate. We report for the first time the identification of arguably indigenous OM present within surface deposits of black glass grains collected on the rim of Shorty crater during the Apollo 17 mission by astronauts Eugene Cernan and Harrison Schmitt.
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Yasui, Minami; Arakawa, Masahiko; Hasegawa, Sunao; Fujita, Yukihiro; Kadono, Toshihiko
2012-11-01
Recent studies of impact craters formed on low-density asteroids led to the proposal of a new crater formation mechanism dominated by pore collapse and compaction. Thus, it is important to study the crater formation process associated with the projectile penetration on porous cohesive targets. Laboratory impact experiments were conducted for a porous gypsum target with porosity of 50%, and flash X-rays were used to visualize the interior of the target for in situ observation of crater formation and projectile penetration. Spherical projectiles made of three different materials, stainless steel, aluminum, and nylon were impacted at 1.9-2.4 km/s (low-velocity impact) and 5.6-6.4 km/s (high-velocity impact) by using a two-stage light-gas gun. Two imaging plates were used to take two X-ray images at a different delay time from the impact moment for one shot. Two types of crater cavity shape were found on the porous gypsum target, that is, penetration holes or hemispherical cavities, depending on the projectile size and density, and the impact velocity. The drag coefficient of a projectile was determined by measuring the penetration depth changing with time, and we found that it was closely related to the crater cavity shape: it was about 0.9 for a penetration hole, while it was 2.3-3.9 for a hemispherical cavity. This large value for a hemispherical cavity could have been caused by the deformation or the disruption of the projectile. The cratering efficiency, ρtVcr(t)/mp, was found to have a power law relationship to the scaling time for crater growth, πt = vit/rp, where vi is the impact velocity, rp is the projectile radius, and t is the time after the impact, and all data for stainless steel and aluminum projectiles merged completely and could be fitted by a power-law equation of ρtVcr(t)/mp=2.69×10-1πt1.10. Furthermore, the scaled crater volume, πV = Vcr_finalρt/mp, where Vcr_final is the final crater cavity volume, ρt is the target density, and mp is the
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1969-01-01
This is the insignia of the Apollo 13 lunar landing mission. Represented in the Apollo 13 emblem is Apollo, the sun god of Greek mythology, symbolizing how the Apollo flights have extended the light of knowledge to all mankind. The Latin phrase Ex Luna, Scientia means 'From the Moon, Knowledge'.
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Crater Degradation on Mercury: A Global Perspective
Kinczyk, M. J.; Byrne, P. K.; Prockter, L. M.; Susorney, H. C. M.; Chapman, C. R.; Barnouin, O. S.
2017-12-01
On geologic timescales, initially fresh craters are subjected to many weathering mechanisms. Whereas water and wind are, or were, effective erosive mechanisms such as on Earth and Mars, micrometeorite bombardment and modification due to subsequent impacts are the dominant processes that degrade craters and crater rays on airless bodies like the Moon and Mercury. Classifying craters based on their state of degradation can help determine the relative ages of landforms proximal to, and crosscut by, these craters. However, this method is most effective when used together with statistical analysis of crater distributions. Pre-MESSENGER degradation classification schemes lacked sufficient detail to be consistently applied to craters of various sizes and morphological types—despite evidence suggesting that the ejecta deposits of large basins persist much longer than those of smaller craters, for instance—yet broad assumptions have been made regarding the correlation of crater class to the planet's time-stratigraphic sequence. Moreover, previous efforts to categorize craters by degradation state have either been restricted to regional study sites or applied only to a subset of crater age or size. As a result, numerous interpretations of crater degradation state persist for Mercury, challenging a complete understanding of this process on the innermost planet. We report on the first global survey of crater degradation on Mercury. By modifying an established 5-class scheme, we have systematically applied a rigorous set of criteria to all craters ≥40 km in diameter on the planet. These criteria include the state and morphology of crater deposits separately (e.g., rim, floor, wall, ejecta) and degradation classes were assigned as the collection of these individual attributes. This approach yields a consistent classification of craters of different sizes. Our results provide the first comprehensive assessment of how craters of various states of degradation are distributed
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Gully formation in terrestrial simple craters: Meteor Crater, USA and Lonar Crater, India
Kumar, P.; Head, J. W.; Kring, D. A.
2007-12-01
Geomorphic features such as gullies, valley networks, and channels on Mars have been used as a proxy to understand the climate and landscape evolution of Mars. Terrestrial analogues provide significant insight as to how the various exogenic and endogenic processes might contribute to the evolution of these martian landscapes. We describe here a terrestrial example from Meteor Crater, which shows a spectacular development of gullies throughout the inner wall in response to rainwater precipitation, snow melting and groundwater discharge. As liquid water has been envisaged as one of the important agents of landscape sculpturing, Meteor Crater remains a useful landmark, where planetary geologists can learn some lessons. We also show here how the lithology and structural framework of this crater controls the gully distribution. Like many martian impact craters, it was emplaced in layered sedimentary rocks with an exceptionally well-developed centripetal drainage pattern consisting of individual alcoves, channels and fans. Some of the gullies originate from the rim crest and others from the middle crater wall, where a lithologic transition occurs. Deeply incised alcoves are well-developed on the soft sandstones of the Coconino Formation exposed on the middle crater wall, beneath overlying dolomite. In general, the gully locations are along crater wall radial fractures and faults, which are favorable locales of groundwater flow and discharge; these structural discontinuities are also the locales where the surface runoff from rain precipitation and snow melting can preferentially flow, causing degradation. Like martian craters, channels are well developed on the talus deposits and alluvial fans on the periphery of the crater floor. In addition, lake sediments on the crater floor provide significant evidence of a past pluvial climate, when groundwater seeped from springs on the crater wall. Caves exposed on the lower crater level may point to percolation of surface runoff
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Evidence from Impact Crater Observations for Few Large Impacts on the Moon 0.8-1.7 Ga
Kirchoff, M. R.; Bottke, W. F.; Marchi, S.; Chapman, C. R.; Enke, B.
2012-12-01
Our Moon is a keystone for understanding the inner solar system impact flux through time, because it is the only body for which we have crater size-frequency distributions (SFDs) through most of bombardment history and radiometric ages of probable associated terrains. Even so, the bombardment rate over the last 3.5 Gyr is poorly understood. According to the spatial density of sub-km craters on dated lunar terrains, the lunar impact flux has been roughly constant over this interval [e.g., 1 and references therein]. If so, one may expect that craters with diameter (D) > 50 km should also be equally dispersed in time over the last 3.5 Gyr. Surprisingly, our new work indicates this may not be so. We have compiled SFDs for small, superposed craters with D~0.6-15 km on the original floors of several previously designated Copernican and Eratothenian craters (USGS Geological Atlas of the Moon and [2]) with D > 50 km using JMARS. Using these data we compute the large craters' formation model ages with the Model Production Function chronology developed by Marchi et al. [3]. Many of these craters, especially on the farside (e.g., Sharnov, Birkeland), can now be suitably examined only because of the excellent LROC imaging (we use the Wide Angle Camera mosaic). As a test of our methods, we calculated the model age of the 55 km crater Aristillus (34°N, 1°E), a relatively young crater thought to have showered the Apollo 15 landing site with ejecta. Interestingly, our model age of 2.2 ± 0.6 Ga is surprisingly consistent with a 2.1 Ga-old impact-derived clast (radiometric age) returned by the Apollo 15 astronauts [4]. We find that nearly all of our computed ages for the large craters are older than indicated by previous work, with very few having ages younger than 3 Ga. Reasons for these discrepancies include (i) use of poor resolution Lunar Orbiter images (especially away from the near side) and (ii) application of the unreliable "DL" method, which involves simplified
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Apollo 16 astronauts in Apollo Command Module Mission Simulator
1972-01-01
Astronaut Thomas K. Mattingly II, command module pilot of the Apollo 16 lunar landing mission, participates in extravehicular activity (EVA) training in bldg 5 at the Manned Spacecraft Center (MSC). In the right background is Astronaut Charles M. Duke Jr., lunar module pilot. They are inside the Apollo Command Module Mission Simulator (31046); Mattingly (right foreground) and Duke (right backgroung) in the Apollo Command Module Mission Simulator for EVA simulation and training. Astronaut John W. Young, commander, can be seen in the left background (31047).
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Mass Movement on Vesta at Steep Scarps and Crater Rims
Krohn, K.; Jaumann, R.; Otto, K.; Hoogenboom, T.; Wagner, R.; Buczkowski, D. L.; Garry, B.; Williams, D. A.; Yingst, R. A.; Scully, J.;
2014-01-01
The Quadrangles Av-11 and Av-12 on Vesta are located at the northern rim of the giant Rheasilvia south polar impact basin. The primary geologic units in Av-11 and Av-12 include material from the Rheasilvia impact basin formation, smooth material and different types of impact crater structures (such as bimodal craters, dark and bright crater ray material and dark ejecta material). Av-11 and Av-12 exhibit almost the full range of mass wasting features observed on Vesta, such as slump blocks, spur-and-gully morphologies and landslides within craters. Processes of collapse, slope instability and seismically triggered events force material to slump down crater walls or scarps and produce landslides or rotational slump blocks. The spur-and-gully morphology that is known to form on Mars is also observed on Vesta; however, on Vesta this morphology formed under dry conditions.
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Mass movement on Vesta at steep scarps and crater rims
Krohn, K.; Jaumann, R.; Otto, K.; Hoogenboom, T.; Wagner, R.; Buczkowski, D. L.; Garry, B.; Williams, D. A.; Yingst, R. A.; Scully, J.; De Sanctis, M. C.; Kneissl, T.; Schmedemann, N.; Kersten, E.; Stephan, K.; Matz, K.-D.; Pieters, C. M.; Preusker, F.; Roatsch, T.; Schenk, P.; Russell, C. T.; Raymond, C. A.
2014-12-01
The Quadrangles Av-11 and Av-12 on Vesta are located at the northern rim of the giant Rheasilvia south polar impact basin. The primary geologic units in Av-11 and Av-12 include material from the Rheasilvia impact basin formation, smooth material and different types of impact crater structures (such as bimodal craters, dark and bright crater ray material and dark ejecta material). Av-11 and Av-12 exhibit almost the full range of mass wasting features observed on Vesta, such as slump blocks, spur-and-gully morphologies and landslides within craters. Processes of collapse, slope instability and seismically triggered events force material to slump down crater walls or scarps and produce landslides or rotational slump blocks. The spur-and-gully morphology that is known to form on Mars is also observed on Vesta; however, on Vesta this morphology formed under dry conditions.
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LRO MOON CRATER EDR RAWDATA VERSION 1.0
National Aeronautics and Space Administration — This data set comprises the raw binary data from from the LRO Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument. The data consists of the...
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Multivariate analyses of crater parameters and the classification of craters
Siegal, B. S.; Griffiths, J. C.
1974-01-01
Multivariate analyses were performed on certain linear dimensions of six genetic types of craters. A total of 320 craters, consisting of laboratory fluidization craters, craters formed by chemical and nuclear explosives, terrestrial maars and other volcanic craters, and terrestrial meteorite impact craters, authenticated and probable, were analyzed in the first data set in terms of their mean rim crest diameter, mean interior relief, rim height, and mean exterior rim width. The second data set contained an additional 91 terrestrial craters of which 19 were of experimental percussive impact and 28 of volcanic collapse origin, and which was analyzed in terms of mean rim crest diameter, mean interior relief, and rim height. Principal component analyses were performed on the six genetic types of craters. Ninety per cent of the variation in the variables can be accounted for by two components. Ninety-nine per cent of the variation in the craters formed by chemical and nuclear explosives is explained by the first component alone.
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Probable age of Autolycus and calibration of lunar stratigraphy
International Nuclear Information System (INIS)
Ryder, G.; Bogard, D.; Garrison, D.
1991-01-01
39 Ar- 40 Ar analyses of three petrographically distinct, shocked Apollo 15 KREEP (i.e., high K, rare earth element, P, and other trace element contents) basalt samples demonstrate that a major impact event affected all three samples at about 2.1 Ga. The Copernican System craters Aristillus and Autolycus are to the north; a ray from one of them crosses the landing site and had been suggested prior to the Apollo 15 mission as a source of material that could be used to date these craters. Autolycus, the older of the two, is in a particularly appropriate terrain and is the most likely source of the 2.1 Ga heating and delivery event. With this calibration point, and if Autolycus really is a Copernican crater, the Copernican System lasted twice as long as has previously been suggested. Furthermore, the Moon was not subjected to a constant cratering rate over the past 3 b.y.; the average rate in the preceding Eratosthenian must have been twice that in the Copernican
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Apollo decommissioning project, Apollo, Pennsylvania. Final technical report
International Nuclear Information System (INIS)
1997-01-01
In November, 1991 Babcock and Wilcox (B and W) received a grant to partially fund the decommissioning of the former Apollo Nuclear Fuel Facility. The decommissioning was performed in accordance with a Nuclear Regulatory Commission (NRC) approved decommissioning plan. This report summarizes the decommissioning of the Apollo Nuclear Fuel Facility and the radiological surveying of the site to demonstrate that these decommissioning activities were effective in reducing residual activity well below NRC's criteria for release for unrestricted use. The Apollo Nuclear Fuel Facility was utilized by the Nuclear Materials and Equipment Corporation (NUMEC) and B and W for nuclear research and production under Atomic Energy Commission and Department of Energy (DOE) contracts during 20 plus years of nuclear fuel manufacturing operations
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2002-01-01
(Released 3 May 2002) The Science The eastern rim of this unnamed crater in Southern Arabia Terra is very degraded (beaten up). This indicates that this crater is very ancient and has been subjected to erosion and subsequent bombardment from other impactors such as asteroids and comets. One of these later (younger) craters is seen in the upper right of this image superimposed upon the older crater rim material. Note that this smaller younger crater rim is sharper and more intact than the older crater rim. This region is also mantled with a blanket of dust. This dust mantle causes the underlying topography to take on a more subdued appearance. The Story When you think of Arabia, you probably think of hot deserts and a lot of profitable oil reserves. On Mars, however, Southern Arabia Terra is a cold place of cratered terrain. This almost frothy-looking image is the badly battered edge of an ancient crater, which has suffered both erosion and bombardment from asteroids, comets, or other impacting bodies over the long course of its existence. A blanket of dust has also settled over the region, which gives the otherwise rugged landscape a soft and more subdued appearance. The small, round crater (upper left) seems almost gemlike in its setting against the larger crater ring. But this companionship is no easy romance. Whatever formed the small crater clearly whammed into the larger crater rim at some point, obliterating part of its edge. You can tell the small crater was formed after the first and more devastating impact, because it is laid over the other larger crater. How much younger is the small one? Well, its rim is also much sharper and more intact, which gives a sense that it is probably far more youthful than the very degraded, ancient crater.
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National Aeronautics and Space Administration — The Apollo Image Atlas is a comprehensive collection of Apollo-Saturn mission photography. Included are almost 25,000 lunar images, both from orbit and from the...
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Cratering Equations for Zinc Orthotitanate Coated Aluminum
Hyde, James; Christiansen, Eric; Liou, Jer-Chyi; Ryan, Shannon
2009-01-01
multiple craters. Samples were obtained from the HST largest craters for examination by electron microscope equipped with x-ray spectrometers to determine impactor source (micrometeoroid or orbital debris). In an attempt to estimate the MMOD particle diameters that produced these craters, this paper will present equations for spall diameter, crater depth and crater diameter in Z93 coated aluminum. The equations will be based on hypervelocity impact tests of Z93 painted aluminum at the NASA White Sands Test Facility. Equations inputs for velocities beyond the testable regime are expected from hydrocode simulations of Z93 coated aluminum using CTH and ANSYS AUTODYN.
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The APOLLO assembly spectrum code
International Nuclear Information System (INIS)
Kavenoky, A.; Sanchez, R.
1987-04-01
The APOLLO code was originally developed as a design tool for HTR's, later it was aimed at the calculation of PWR lattices. APOLLO is a general purpose assembly spectrum code based on the multigroup integral transport equation; refined collision probability modules allow the computation of 1D geometries with linearly anisotropic scattering and two term flux expansion. In 2D geometries modules based on the substructure method provide fast and accurate design calculations and a module based on a direct discretization is devoted to reference calculations. The SPH homogenization technique provides corrected cross sections performing an equivalence between coarse and refined calculations. The post processing module of APOLLO generate either APOLLIB to be used by APOLLO or NEPLIB for reactor diffusion calculation. The cross section library of APOLLO contains data and self-shielding data for more than 400 isotopes. APOLLO is able to compute the depletion of any medium accounting for any heavy isotope or fission product chain. 21 refs
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International Nuclear Information System (INIS)
Moore, J.M.; Malin, M.C.
1987-01-01
Voyager observations reveal impact craters on Ganymede that are characterized by the presence of broad, high albedo, topographic domes situated within a central pit. Fifty-seven craters with central domes were identified in images covering approx. 50% of the surface. Owing to limitations in resolution, and viewing and illumination angles, the features identified are most likely a subset of dome craters. The sample appears to be sufficiently large to infer statistically meaningful trends. Dome craters appear to fall into two distinct populations on plots of the ratio of dome diameter to crater rim diameter, large-dome craters and small-dome craters. The two classes are morphologically distinct from one another. In general, large dome craters show little relief and their constituent landforms appear subdued with respect to fresh craters. The physical attributes of small-dome craters are more sharply defined, a characteristic they share with young impact craters of comparable size observed elsewhere in the solar system. Both types of dome craters exhibit central pits in which the dome is located. As it is difficult to produce domes by impact and/or erosional processes, an endogenic origin for the domes is reasonably inferred. Several hypotheses for their origin are proposed. These hypotheses are briefly reviewed
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Look, B. C.; Tremor, J. W.; Barrows, W. F.; Zabower, H. R.; Suri, K.; Park, E. G., Jr.; Durso, J. A.; Leon, H. A.; Haymaker, W.; Lindberg, R. G.
1975-01-01
A closed passive system independent of support from the spacecraft or its crew was developed to house five pocket mice for their flight on Apollo XVII. The reaction of potassium superoxide with carbon dioxide and water vapor to produce oxygen provided a habitable atmosphere within the experiment package. The performance of the system and the ability of the mice to survive the key preflight tests gave reasonable assurance that the mice would also withstand the Apollo flight.-
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Apollo for Adobe Flex Developers Pocket Guide A Developer's Reference for Apollo's Alpha Release
Chambers, Mike; Swartz, Jeff
2009-01-01
Now you can build and deploy Flash-based Rich Internet Applications (RIAs) to the desktop using Adobe's Flex framework. Written by members of the Apollo product team, this is the official guide to the Alpha release of Adobe Apollo, the new cross platform desktop runtime from Adobe Labs. Numerous examples illustrate how Apollo works so you can start building RIAs for the desktop right away.
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Smith, M. C., Jr.; Heidelbaugh, N. D.; Rambaut, P. C.; Rapp, R. M.; Wheeler, H. O.; Huber, C. S.; Bourland, C. T.
1975-01-01
Large improvements and advances in space food systems achieved during the Apollo food program are discussed. Modifications of the Apollo food system were directed primarily toward improving delivery of adequate nutrition to the astronaut. Individual food items and flight menus were modified as nutritional countermeasures to the effects of weightlessness. Unique food items were developed, including some that provided nutritional completeness, high acceptability, and ready-to-eat, shelf-stable convenience. Specialized food packages were also developed. The Apollo program experience clearly showed that future space food systems will require well-directed efforts to achieve the optimum potential of food systems in support of the physiological and psychological well-being of astronauts and crews.
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International Nuclear Information System (INIS)
Kitts, K.; Sutton, S.; Newville, M.
2007-01-01
We report (1) a new method for determining the relative abundances in situ of Cr, Mn, Fe and Ni in implanted solar wind in individual Apollo 16 and 17 lunar plagioclases via synchrotron X-ray fluorescence and (2) the charge states of these metals. By virture of its mass alone, the Sun provides a representative composition of the solar system and can be used as a background against which to gauge excesses or deficiencies of specific components. One way of sampling the Sun is by measuring solar wind implanted ions in lunar soil grains. Such measurements are valuable because of their long exposure ages which compliment shorter time scale collections, such as those obtained by the Genesis spacecraft. Kitts et al. sought to determine the isotopic composition of solar Cr by analyzing the solar wind implanted into plagioclase grains from Apollo 16 lunar soils. The isotopic composition of the solar wind bearing fraction was anomalous and did not match any other known Cr isotopic signature. This could only be explained by either (1) an enrichment in the solar wind of heavy Cr due to spallation in the solar atmosphere or (2) that the Earth and the various parent bodies of the meteorites are distinct from the Sun and must have formed from slightly different mixes of presolar materials. To help resolve this issue, we have developed a wholly independent method for determining the relative abundances of transition metals in the solar wind implanted in individual lunar soil grains. This method is based on in situ abundance measurements by microbeam x-ray fluorescence in both the implantation zone and bulk grains using the synchrotron x-ray microprobe at the Advanced Photon Source (GSECARS sector 13) at Argonne National Laboratory. Here, we report results for Apollo 16 and 17 plagioclase grains. Additionally, a micro-XANES technique was used to determine charge states of the implanted Cr, Mn, Fe and Ni.
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Pyroclastic Deposits in the Floor-fractured Crater Alphonsus
Allen, Carlton C.; Donaldson-Hanna, Kerri L.; Pieters, Carle M.; Moriarty, Daniel P.; Greenhagen, Benjamin T.; Bennett, Kristen A.; Kramer, Georgiana Y.; Paige, David A.
2013-01-01
Alphonsus, the 118 km diameter floor-fractured crater, is located immediately east of Mare Nubium. Eleven pyroclastic deposits have been identified on the crater's floor. Early telescopic spectra suggest that the floor of Alphonsus is noritic, and that the pyroclastic deposits contain mixtures of floor material and a juvenile component including basaltic glass. Head and Wilson contend that Nubium lavas intruded the breccia zone beneath Alphonsus, forming dikes and fractures on the crater floor. In this model, the magma ascended to the level of the mare but cooled underground, and a portion broke thru to the surface in vulcanian (explosive) eruptions. Alternatively, the erupted material could be from a source unrelated to the mare, in the style of regional pyroclastic deposits. High-resolution images and spectroscopy from the Moon Mineralogy Mapper (M3), Diviner Lunar Radiometer, and Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (NAC) provide data to test these formation models. Spectra from M3 confirm that the crater floor is primarily composed of noritic material, and that the Nubium lavas are basaltic. Spectra from the three largest pyroclastic deposits in Alphonsus are consistent with a minor low- Ca pyroxene component in a glass-rich matrix. The centers of the 2 micron absorption bands have wavelengths too short to be of the same origin as the Nubium basalts. Diviner Christiansen feature (CF) values were used to estimate FeO abundances for the crater floor, Nubium soil, and pyroclastic deposits. The estimated abundance for the crater floor (7.5 +/- 1.4 wt.%) is within the range of FeO values for Apollo norite samples. However, the estimated FeO abundance for Nubium soil (13.4 +/- 1.4 wt.%) is lower than those measured in most mare samples. The difference may reflect contamination of the mare soil by highland ejecta. The Diviner-derived FeO abundance for the western pyroclastic deposit is 13.8 +/- 3.3 wt.%. This is lower than the values for mare soil
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Williams, David A.; Denevi, Brett W.; Mittlefehldt, David W.; Mest, Scott C.; Schenk, Paul M.; Yingst, R. Aileen; Buczowski, Debra L.; Scully, Jennifer E. C.; Garry, W. Brent; McCord, Thomas B.;
2014-01-01
We used Dawn spacecraft data to identify and delineate geological units and landforms in the Marcia quadrangle of Vesta as a means to assess the role of the large, relatively young impact craters Marcia (approximately 63 kilometers diameter) and Calpurnia (approximately 53 kilometers diameter) and their surrounding ejecta field on the local geology. We also investigated a local topographic high with a dark-rayed crater named Aricia Tholus, and the impact crater Octavia that is surrounded by a distinctive diffuse mantle. Crater counts and stratigraphic relations suggest that Marcia is the youngest large crater on Vesta, in which a putative impact melt on the crater floor ranges in age between approximately 40 and 60 million years (depending upon choice of chronology system), and Marcia's ejecta blanket ranges in age between approximately 120 and 390 million years (depending upon choice of chronology system). We interpret the geologic units in and around Marcia crater to mark a major Vestan time-stratigraphic event, and that the Marcia Formation is one of the geologically youngest formations on Vesta. Marcia crater reveals pristine bright and dark material in its walls and smooth and pitted terrains on its floor. The smooth unit we interpret as evidence of flow of impact melts and (for the pitted terrain) release of volatiles during or after the impact process. The distinctive dark ejecta surrounding craters Marcia and Calpurnia is enriched in OH- or H-bearing phases and has a variable morphology, suggestive of a complex mixture of impact ejecta and impact melts including dark materials possibly derived from carbonaceous chondrite-rich material. Aricia Tholus, which was originally interpreted as a putative Vestan volcanic edifice based on lower resolution observations, appears to be a fragment of an ancient impact basin rim topped by a dark-rayed impact crater. Octavia crater has a cratering model formation age of approximately 280-990 million years based on counts
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Centrifuge impact cratering experiment 5
1984-01-01
Transient crates motions, cratering flow fields, crates dynamics, determining impact conditions from total crater welt, centrifuge quarter-space cratering, and impact cratering mechanics research is documented.
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Vincent, J.; Oklay, N.; Marchi, S.; Höfner, S.; Sierks, H.
2014-07-01
This paper reviews the observations of crater-like features on cometary nuclei. ''Pits'' have been observed on almost all cometary nuclei but their origin is not fully understood [1,2,3,4]. It is currently assumed that they are created mainly by the cometary activity with a pocket of volatiles erupting under a dust crust, leaving a hole behind. There are, however, other features which cannot be explained in this way and are interpreted alternatively as remnants of impact craters. This work focusses on the second type of pit features: impact craters. We present an in-depth review of what has been observed previously and conclude that two main types of crater morphologies can be observed: ''pit-halo'' and ''sharp pit''. We extend this review by a series of analysis of impact craters on cometary nuclei through different approaches [5]: (1) Probability of impact: We discuss the chances that a Jupiter Family Comet like 9P/Tempel 1 or the target of Rosetta 67P/Churyumov-Gerasimenko can experience an impact, taking into account the most recent work on the size distribution of small objects in the asteroid Main Belt [6]. (2) Crater morphology from scaling laws: We present the status of scaling laws for impact craters on cometary nuclei [7] and discuss their strengths and limitations when modeling what happens when a rocky projectile hits a very porous material. (3) Numerical experiments: We extend the work on scaling laws by a series of hydrocode impact simulations, using the iSALE shock physics code [8,9,10] for varying surface porosity and impactor velocity (see Figure). (4) Surface processes and evolution: We discuss finally the fate of the projectile and the effects of the impact-induced surface compaction on the activity of the nucleus. To summarize, we find that comets do undergo impacts although the rapid evolution of the surface erases most of the features and make craters difficult to detect. In the case of a collision between a rocky body and a highly porous
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Experimental impact crater morphology
Dufresne, A.; Poelchau, M. H.; Hoerth, T.; Schaefer, F.; Thoma, K.; Deutsch, A.; Kenkmann, T.
2012-04-01
The research group MEMIN (Multidisciplinary Experimental and Impact Modelling Research Network) is conducting impact experiments into porous sandstones, examining, among other parameters, the influence of target pore-space saturation with water, and projectile velocity, density and mass, on the cratering process. The high-velocity (2.5-7.8 km/s) impact experiments were carried out at the two-stage light-gas gun facilities of the Fraunhofer Institute EMI (Germany) using steel, iron meteorite (Campo del Cielo IAB), and aluminium projectiles with Seeberg Sandstone as targets. The primary objectives of this study within MEMIN are to provide detailed morphometric data of the experimental craters, and to identify trends and characteristics specific to a given impact parameter. Generally, all craters, regardless of impact conditions, have an inner depression within a highly fragile, white-coloured centre, an outer spallation (i.e. tensile failure) zone, and areas of arrested spallation (i.e. spall fragments that were not completely dislodged from the target) at the crater rim. Within this general morphological framework, distinct trends and differences in crater dimensions and morphological characteristics are identified. With increasing impact velocity, the volume of craters in dry targets increases by a factor of ~4 when doubling velocity. At identical impact conditions (steel projectiles, ~5km/s), craters in dry and wet sandstone targets differ significantly in that "wet" craters are up to 76% larger in volume, have depth-diameter ratios generally below 0.19 (whereas dry craters are almost consistently above this value) at significantly larger diameters, and their spallation zone morphologies show very different characteristics. In dry craters, the spall zone surfaces dip evenly at 10-20° towards the crater centre. In wet craters, on the other hand, they consist of slightly convex slopes of 10-35° adjacent to the inner depression, and of sub-horizontal tensile
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Vertical view Apollo 16 Descartes landing sites as photographed by Apollo 14
1972-01-01
An almost vertical view of the Apollo 16 Descartes landing sites as photographed from the Apollo 14 spacecraft. Overlays are provided to point out extravehicular activity (EVA), Lunar Roving Vehicle (LRV) travers routes and the nicknames of features. The Roman numerals indicate the EVA numbers and the Arabic numbers point out stations or traverse stops.
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van der Bogert, C. H.; Hiesinger, H.; Dundas, C. M.; Krüger, T.; McEwen, A. S.; Zanetti, M.; Robinson, M. S.
2017-12-01
Recent work on dating Copernican-aged craters, using Lunar Reconnaissance Orbiter (LRO) Camera data, re-encountered a curious discrepancy in crater size-frequency distribution (CSFD) measurements that was observed, but not understood, during the Apollo era. For example, at Tycho, Copernicus, and Aristarchus craters, CSFDs of impact melt deposits give significantly younger relative and absolute model ages (AMAs) than impact ejecta blankets, although these two units formed during one impact event, and would ideally yield coeval ages at the resolution of the CSFD technique. We investigated the effects of contrasting target properties on CSFDs and their resultant relative and absolute model ages for coeval lunar impact melt and ejecta units. We counted craters with diameters through the transition from strength- to gravity-scaling on two large impact melt deposits at Tycho and King craters, and we used pi-group scaling calculations to model the effects of differing target properties on final crater diameters for five different theoretical lunar targets. The new CSFD for the large King Crater melt pond bridges the gap between the discrepant CSFDs within a single geologic unit. Thus, the observed trends in the impact melt CSFDs support the occurrence of target property effects, rather than self-secondary and/or field secondary contamination. The CSFDs generated from the pi-group scaling calculations show that targets with higher density and effective strength yield smaller crater diameters than weaker targets, such that the relative ages of the former are lower relative to the latter. Consequently, coeval impact melt and ejecta units will have discrepant apparent ages. Target property differences also affect the resulting slope of the CSFD, with stronger targets exhibiting shallower slopes, so that the final crater diameters may differ more greatly at smaller diameters. Besides their application to age dating, the CSFDs may provide additional information about the
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Apollo rocks, fines and soil cores
Allton, J.; Bevill, T.
Apollo rocks and soils not only established basic lunar properties and ground truth for global remote sensing, they also provided important lessons for planetary protection (Adv. Space Res ., 1998, v. 22, no. 3 pp. 373-382). The six Apollo missions returned 2196 samples weighing 381.7 kg, comprised of rocks, fines, soil cores and 2 gas samples. By examining which samples were allocated for scientific investigations, information was obtained on usefulness of sampling strategy, sampling devices and containers, sample types and diversity, and on size of sample needed by various disciplines. Diversity was increased by using rakes to gather small rocks on the Moon and by removing fragments >1 mm from soils by sieving in the laboratory. Breccias and soil cores are diverse internally. Per unit weight these samples were more often allocated for research. Apollo investigators became adept at wringing information from very small sample sizes. By pushing the analytical limits, the main concern was adequate size for representative sampling. Typical allocations for trace element analyses were 750 mg for rocks, 300 mg for fines and 70 mg for core subsamples. Age-dating and isotope systematics allocations were typically 1 g for rocks and fines, but only 10% of that amount for core depth subsamples. Historically, allocations for organics and microbiology were 4 g (10% for cores). Modern allocations for biomarker detection are 100mg. Other disciplines supported have been cosmogenic nuclides, rock and soil petrology, sedimentary volatiles, reflectance, magnetics, and biohazard studies . Highly applicable to future sample return missions was the Apollo experience with organic contamination, estimated to be from 1 to 5 ng/g sample for Apollo 11 (Simonheit &Flory, 1970; Apollo 11, 12 &13 Organic contamination Monitoring History, U.C. Berkeley; Burlingame et al., 1970, Apollo 11 LSC , pp. 1779-1792). Eleven sources of contaminants, of which 7 are applicable to robotic missions, were
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Distribution of inert gases in fines from the Cayley-Descartes region
Walton, J. R.; Lakatos, S.; Heymann, D.
1973-01-01
The inert gases in 14 different fines and in one sample of 2 to 4 mm fines from Apollo 16 were measured by mass spectroscopy with respect to trapped solar wind gases, cosmogenic gases, and 'parentless' Ar-40. Such studies are helpful for the understanding of regolith evolution, of transport of regolith fines, and of the lunar atmosphere. The Apollo 16 soils are unique because they represent, after Luna 20, the second and much more extensive record from the lunar highlands. The landing site presents the problem of materials from the Cayley Formation vs those from the Descartes Formation. There are two large, relatively fresh craters in the area, North Ray and South Ray, whose ejecta patterns may be recognized in the inert-gas record.
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How to find the Apollo landing sites
Chen, James L
2014-01-01
This book is for anyone who wants to be able to connect the history of lunar exploration to the Moon visible above. It addresses what Apollo equipment and experiments were left behind and what the Apollo landings sites look like now. Each Apollo mission is examined in detail, with photos that progressively zoom-in to guide the reader in locating the Apollo landing sites. Guided by official NASA photographs from the Lunar Reconnaissance Orbiter and the original Apollo missions, the reader can view the Moon with a new appreciation of the accomplishment of landing astronauts on its surface. Countless people have gazed at the Moon in the night sky knowing the successes of the Apollo Program in landing men on the Moon. After the information in this guide, casual and serious observers can actually point out where the Apollo landings occurred as well as knowing why those sites were chosen.
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Chemical stratigraphy of the Apollo 17 deep drill cores 70009-70007
Ehmann, W. D.; Ali, M. Z.
1977-01-01
A description is presented of an analysis of a total of 26 samples from three core segments (70009, 70008, 70007) of the Apollo 17 deep drill string. The deep drill string was taken about 700 m east of the Camelot Crater in the Taurus-Littrow region of the moon. Three core segments have been chemically characterized from the mainly coarse-grained upper portion of the deep drill string. The chemical data suggest that the entire 70007-70009 portion of the deep drill string examined was not deposited as a single unit, but was formed by several events sampling slightly different source materials which may have occurred over a relatively short period of time. According to the data from drill stem 70007, there were at least two phases of deposition. Core segment 70009 is probably derived from somewhat different source material than 70008. It seems to be a very well mixed material.
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Digital Apollo: human and machine in spaceflight
National Research Council Canada - National Science Library
Mindell, David A
2008-01-01
... had just landed on the moon and begun transmitting images to NASA. Project Gemini was drawing to a close, Apollo hardware was beginning to emerge from factories, and Apollo software was experiencing a crisis. And on that day I was born. I do not remember the first lunar landing of Apollo 11 or the drama of Apollo 13, but I do remember watching the late...
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International Nuclear Information System (INIS)
Treiman, Allan H.; Bish, David L.; Chipera, Steve J.; Blake, David F.
2015-01-01
The Windjana drill sample, a sandstone of the Dillinger member (Kimberley formation, Gale Crater, Mars), was analyzed by CheMin X-ray diffraction (XRD) in the MSL Curiosity rover. From Rietveld refinements of its XRD pattern, Windjana contains the following: sanidine (21% weight, ~Or 95 ); augite (20%); magnetite (12%); pigeonite; olivine; plagioclase; amorphous and smectitic material (~25%); and percent levels of others including ilmenite, fluorapatite, and bassanite. From mass balance on the Alpha Proton X-ray Spectrometer (APXS) chemical analysis, the amorphous material is Fe rich with nearly no other cations—like ferrihydrite. The Windjana sample shows little alteration and was likely cemented by its magnetite and ferrihydrite. From ChemCam Laser-Induced Breakdown Spectrometer (LIBS) chemical analyses, Windjana is representative of the Dillinger and Mount Remarkable members of the Kimberley formation. LIBS data suggest that the Kimberley sediments include at least three chemical components. The most K-rich targets have 5.6% K 2 O, ~1.8 times that of Windjana, implying a sediment component with >40% sanidine, e.g., a trachyte. A second component is rich in mafic minerals, with little feldspar (like a shergottite). A third component is richer in plagioclase and in Na 2 O, and is likely to be basaltic. The K-rich sediment component is consistent with APXS and ChemCam observations of K-rich rocks elsewhere in Gale Crater. The source of this sediment component was likely volcanic. Finally, the presence of sediment from many igneous sources, in concert with Curiosity's identifications of other igneous materials (e.g., mugearite), implies that the northern rim of Gale Crater exposes a diverse igneous complex, at least as diverse as that found in similar-age terranes on Earth.
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Fassett, Caleb I.; Crowley, Malinda C.; Leight, Clarissa; Dyar, M. Darby; Minton, David A.; Hirabayashi, Masatoshi; Thomson, Bradley J.; Watters, Wesley A.
2017-06-01
Examining the topography of impact craters and their evolution with time is useful for assessing how fast planetary surfaces evolve. Here, new measurements of depth/diameter (d/D) ratios for 204 craters of 2.5 to 5 km in diameter superposed on Mercury's smooth plains are reported. The median d/D is 0.13, much lower than expected for newly formed simple craters ( 0.21). In comparison, lunar craters that postdate the maria are much less modified, and the median crater in the same size range has a d/D ratio that is nearly indistinguishable from the fresh value. This difference in crater degradation is remarkable given that Mercury's smooth plains and the lunar maria likely have ages that are comparable, if not identical. Applying a topographic diffusion model, these results imply that crater degradation is faster by a factor of approximately two on Mercury than on the Moon, suggesting more rapid landform evolution on Mercury at all scales.Plain Language SummaryMercury and the Moon are both airless bodies that have experienced numerous impact events over billions of years. These impacts form craters in a geologic instant. The question examined in this manuscript is how fast these craters erode after their formation. To simplify the problem, we examined craters of a particular size (2.5 to 5 km in diameter) on a particular geologic terrain type (volcanic smooth plains) on both the Moon and Mercury. We then measured the topography of hundreds of craters on both bodies that met these criteria. Our results suggest that craters on Mercury become shallower much more quickly than craters on the Moon. We estimate that Mercury's topography erodes at a rate at least a factor of two faster than the Moon's.
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Barlow, Nadine G.; Boyce, Joseph M.; Cornwall, Carin
2014-09-01
Low-Aspect-Ratio Layered Ejecta (LARLE) craters are a unique landform found on Mars. LARLE craters are characterized by a crater and normal layered ejecta pattern surrounded by an extensive but thin outer deposit which terminates in a sinuous, almost flame-like morphology. We have conducted a survey to identify all LARLE craters ⩾1-km-diameter within the ±75° latitude zone and to determine their morphologic and morphometric characteristics. The survey reveals 140 LARLE craters, with the majority (91%) located poleward of 40°S and 35°N and all occurring within thick mantles of fine-grained deposits which are likely ice-rich. LARLE craters range in diameter from the cut-off limit of 1 km up to 12.2 km, with 83% being smaller than 5 km. The radius of the outer LARLE deposit displays a linear trend with the crater radius and is greatest at higher polar latitudes. The LARLE deposit ranges in length between 2.56 and 14.81 crater radii in average extent, with maximum length extending up to 21.4 crater radii. The LARLE layer is very sinuous, with lobateness values ranging between 1.45 and 4.35. LARLE craters display a number of characteristics in common with pedestal craters and we propose that pedestal craters are eroded versions of LARLE craters. The distribution and characteristics of the LARLE craters lead us to propose that impact excavation into ice-rich fine-grained deposits produces a dusty base surge cloud (like those produced by explosion craters) that deposits dust and ice particles to create the LARLE layers. Salts emplaced by upward migration of water through the LARLE deposit produce a surficial duricrust layer which protects the deposit from immediate removal by eolian processes.
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Chao, E.C.T.
1973-01-01
On the basis of petrographic and laboratory and active seismic data for the Fra Mauro breccias, and by comparison with the nature and distribution of the ejecta from the Ries crater, Germany, some tentative conclusions regarding the geologic significance of the Fra Mauro Formation on the moon can be drawn. The Fra Mauro Formation, as a whole, consists of unwcldcd, porous ejecta, slightly less porous than the regolith. It contains hand-specimen and larger size clasts of strongly annealed complex breccias, partly to slightly annealed breccias, basalts, and perhaps spherule-rich breccias. These clasts are embedded in a matrix of porous aggregate dominated by mineral and breccia fragments and probably largely free of undevitrified glass. All strongly annealed hand-specimen-size breccias are clasts in the Fra Mauro Formation. To account for the porous, unwelded state of the Fra Mauro Formation, the ejecta must have been deposited at a temperature below that required for welding and annealing. Large boulders probably compacted by the Cone crater event occur near the rim of the crater. They probably consist of a similar suite of fragments, but are probably less porous than the formation. The geochronologic clocks of fragments in the Fra Mauro Formation, with textures ranging from unannealed to strongly annealed, were not reset or strongly modified by the Imbrian event. Strongly annealed breccia clasts and basalt clasts are pre-Imbrian, and probably existed as ejecta mixed with basalt flows in the Imbrium Basin prior to the Imbrian event. The Imbrian event probably occurred between 3.90 or 3.88 and 3.65 b.y. ago.
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PDS Archive Release of Apollo 11, Apollo 12, and Apollo 17 Lunar Rock Sample Images
Garcia, P. A.; Stefanov, W. L.; Lofgren, G. E.; Todd, N. S.; Gaddis, L. R.
2013-01-01
Scientists at the Johnson Space Center (JSC) Lunar Sample Laboratory, Information Resources Directorate, and Image Science & Analysis Laboratory have been working to digitize (scan) the original film negatives of Apollo Lunar Rock Sample photographs [1, 2]. The rock samples, and associated regolith and lunar core samples, were obtained during the Apollo 11, 12, 14, 15, 16 and 17 missions. The images allow scientists to view the individual rock samples in their original or subdivided state prior to requesting physical samples for their research. In cases where access to the actual physical samples is not practical, the images provide an alternate mechanism for study of the subject samples. As the negatives are being scanned, they have been formatted and documented for permanent archive in the NASA Planetary Data System (PDS). The Astromaterials Research and Exploration Science Directorate (which includes the Lunar Sample Laboratory and Image Science & Analysis Laboratory) at JSC is working collaboratively with the Imaging Node of the PDS on the archiving of these valuable data. The PDS Imaging Node is now pleased to announce the release of the image archives for Apollo missions 11, 12, and 17.
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DEFF Research Database (Denmark)
Østermark-Johansen, Lene
2015-01-01
Walter Pater’s fascination with the Hyperborean Apollo, who according to myth resided north of the home of the northern wind, is explored in two of his pieces of short fiction, ‘Duke Carl of Rosenmold’ (1887) and ‘Apollo in Picardy’ (1893). The essay discusses some of Pater’s complex dialogue wit...
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Apollo The Definitive Sourcebook
Orloff, Richard W
2006-01-01
On 25 May 1961, John F Kennedy announced the goal of landing an American man on the Moon by the end of the decade. This challenge forced NASA to review the planned lunar landing of a three-man spaceship named Apollo in the mid-1970s. In 1962, it was decided that a specialized vehicle would accompany the main spacecraft, to make the lunar landing while the mothership remained in lunar orbit. To send these vehicles to the Moon would require the development of an enormous rocket. Development was protracted, but in December 1968 Apollo 8 was launched on a pioneering mission to perform an initial reconnaissance in lunar orbit. When Apollo 17 lifted off from the Moon in December 1972, the program was concluded. Now, at long last, there is a real prospect of a resumption of human exploration of the Moon. This book provides an overview of the origins of the Apollo program and descriptions of the ground facilities, launch vehicles and spacecraft that will serve as an invaluable single-volume sourcebook for space enthu...
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Komatsu, Goro; Senthil Kumar, P.; Goto, Kazuhisa; Sekine, Yasuhito; Giri, Chaitanya; Matsui, Takafumi
2014-05-01
Lonar, a 1.8-km-diameter impact crater in India, is a rare example of terrestrial impact craters formed in basaltic bedrock. The estimated age of the crater ranges widely from less than 12 ka to over 600 ka, but the crater preserves a relatively pristine morphology. We conducted a study of various drainage systems of Lonar Crater. The crater floor hosts a shallow 5-m-deep lake, which fluctuates seasonally. Our investigation reveals that the lake level is influenced by surface runoff that is active during the monsoon and groundwater input effective during both the rainy and the dry seasons. The groundwater discharge is observed as springs on the inner rim walls corresponding to weathered vesicular basalt and/or proximal ejecta, which are underlain by thick massive basalt layers. This observation indicates that groundwater movement is lithologically controlled: it passes preferentially through permeable vesicular basalt or proximal ejecta but is hindered in less permeable massive basalt. It is hypothesized that groundwater is also structurally controlled by dipping of basalt layers, interconnectivity of the permeable lithologic units through fractures, and preferential pathways such as fractures within the permeable lithologic units. Investigation on hydrological processes at Lonar Crater and its lake could provide useful insights into purported paleo-crater lakes presumably formed in the basaltic crust of Mars. The Lonar Crater interior shows signs of degradation in the forms of gullies and debris flows, and the Dhar valley incising in the rim leading to form a fan delta. The ejecta surface is characterized by the presence of channels, originating from the rim area and extending radially away from the crater center. The channels probably resulted from surface runoff, and its erosion contributes to the removal of the ejecta. Lonar Crater is a valuable analog site for studying degradation processes with potential application to impact craters occurring on
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Centrifuge Impact Cratering Experiments
Schmidt, R. M.; Housen, K. R.; Bjorkman, M. D.
1985-01-01
The kinematics of crater growth, impact induced target flow fields and the generation of impact melt were determined. The feasibility of using scaling relationships for impact melt and crater dimensions to determine impactor size and velocity was studied. It is concluded that a coupling parameter determines both the quantity of melt and the crater dimensions for impact velocities greater than 10km/s. As a result impactor radius, a, or velocity, U cannot be determined individually, but only as a product in the form of a coupling parameter, delta U micron. The melt volume and crater volume scaling relations were applied to Brent crater. The transport of melt and the validity of the melt volume scaling relations are examined.
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Mercury's Densely Cratered Surface
1974-01-01
Mariner 10 took this picture (FDS 27465) of the densely cratered surface of Mercury when the spacecraft was 18,200 kilometers (8085 miles) from the planet on March 29. The dark line across top of picture is a 'dropout' of a few TV lines of data. At lower left, a portion of a 61 kilometer (38 mile) crater shows a flow front extending across the crater floor and filling more than half of the crater. The smaller, fresh crater at center is about 25 kilometers (15 miles) in diameter. Craters as small as one kilometer (about one-half mile) across are visible in the picture.The Mariner 10 mission, managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, explored Venus in February 1974 on the way to three encounters with Mercury-in March and September 1974 and in March 1975. The spacecraft took more than 7,000 photos of Mercury, Venus, the Earth and the Moon.Image Credit: NASA/JPL/Northwestern University
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2003-01-01
MGS MOC Release No. MOC2-365, 19 May 2003Beneath the northern plains of Mars are numerous buried meteor impact craters. One of the most heavily-cratered areas, although buried, occurs in Utopia Planitia, as shown in this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image. The history of Mars is complex; impact craters provide a tool by which to understand some of that history. In this case, a very ancient, cratered surface was thinly-buried by younger material that is not cratered at all. This area is near 48.1oN, 228.2oW; less than 180 km (112 mi) west of the Viking 2 lander site. Sunlight illuminates the scene from the lower left.
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Lunar magnetic anomalies detected by the Apollo substatellite magnetometers
Hood, L.L.; Coleman, P.J.; Russell, C.T.; Wilhelms, D.E.
1979-01-01
Properties of lunar crustal magnetization thus far deduced from Apollo subsatellite magnetometer data are reviewed using two of the most accurate presently available magnetic anomaly maps - one covering a portion of the lunar near side and the other a part of the far side. The largest single anomaly found within the region of coverage on the near-side map correlates exactly with a conspicuous, light-colored marking in western Oceanus Procellarum called Reiner Gamma. This feature is interpreted as an unusual deposit of ejecta from secondary craters of the large nearby primary impact crater Cavalerius. An age for Cavalerius (and, by implication, for Reiner Gamma) of 3.2 ?? 0.2 ?? 109 y is estimated. The main (30 ?? 60 km) Reiner Gamma deposit is nearly uniformly magnetized in a single direction, with a minimum mean magnetization intensity of ???7 ?? 10-2 G cm3/g (assuming a density of 3 g/cm3), or about 700 times the stable magnetization component of the most magnetic returned samples. Additional medium-amplitude anomalies exist over the Fra Mauro Formation (Imbrium basin ejecta emplaced ???3.9 ?? 109 y ago) where it has not been flooded by mare basalt flows, but are nearly absent over the maria and over the craters Copernicus, Kepler, and Reiner and their encircling ejecta mantles. The mean altitude of the far-side anomaly gap is much higher than that of the near-side map and the surface geology is more complex, so individual anomaly sources have not yet been identified. However, it is clear that a concentration of especially strong sources exists in the vicinity of the craters Van de Graaff and Aitken. Numerical modeling of the associated fields reveals that the source locations do not correspond with the larger primary impact craters of the region and, by analogy with Reiner Gamma, may be less conspicuous secondary crater ejecta deposits. The reason for a special concentration of strong sources in the Van de Graaff-Aitken region is unknown, but may be indirectly
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Moon/Mars Landing Commemorative Release: Gusev Crater and Ma'adim Vallis
1998-01-01
On July 20, 1969, the first human beings landed on the Moon. On July 20, 1976, the first robotic lander touched down on Mars. This July 20th-- 29 years after Apollo 11 and 22 years since the Viking 1 Mars landing-- we take a look forward toward one possible future exploration site on the red planet.One of the advantages of the Mars Global Surveyor Mars Orbiter Camera (MOC) over its predecessors on the Viking and Mariner spacecraft is resolution. The ability to see-- resolve--fine details on the martian surface is key to planning future landing sites for robotic and, perhaps, human explorers that may one day visit the planet.At present, NASA is studying potential landing sites for the Mars Surveyor landers, rovers, and sample return vehicles that are scheduled to be launched in 2001, 2003, and 2005. Among the types of sites being considered for these early 21st Century landings are those with 'exobiologic potential'--that is, locations on Mars that are in some way related to the past presence of water.For more than a decade, two of the prime candidates suggested by various Mars research scientists are Gusev Crater and Ma'adim Vallis. Located in the martian southern cratered highlands at 14.7o S, 184.5o W, Gusev Crater is a large, ancient, meteor impact basin that--after it formed--was breached by Ma'adim Vallis.Viking Orbiter observations provided some evidence to suggest that a fluid--most likely, water--once flowed through Ma'adim Vallis and into Gusev Crater. Some scientists have suggested that there were many episodes of flow into Gusev Crater (as well as flow out of Gusev through its topographically-lower northwestern rim). Some have also indicated that there were times when Ma'adim Vallis, also, was full of water such that it formed a long, narrow lake.The possibility that water flowed into Gusev Crater and formed a lake has led to the suggestion that the materials seen on the floor of this crater--smooth-surfaced deposits, buried craters, and huge mesas near
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Size-Frequency Distribution of Small Lunar Craters: Widening with Degradation and Crater Lifetime
Ivanov, B. A.
2018-01-01
The review and new measurements are presented for depth/diameter ratio and slope angle evolution during small ( D model. The uncertainty of crater retention age due to crater degradational widening is estimated. The collected and analyzed data are discussed to be used in the future updating of mechanical models for lunar crater aging.
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International Nuclear Information System (INIS)
Grove, T.L.
1985-01-01
The geologic history of the quartz normative (QNB) and olivine normative (ONB) basalt types at Hadley Rille are discussed. A model for the geology of the mare basalts was constructed from a combination of field observations, sample chemistry, sample petrology and personal bias from terrestrial experience. The model proposes that the QNBs are the only mare lava type that is present as outcrop in the area traversed by the astronauts during the Apollo 15 mission. The returned QNB samples formed during a single eruptive phase of the Hadley Rille lava tube system. The ONB lavas are an exotic component transported to the site by a cratering event, or the ONBs are samples excavated from older are bedrock that was partly covered by the QNB lavas
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A model for the dynamics of crater-centered intrusion: Application to lunar floor-fractured craters
Thorey, Clément; Michaut, Chloé
2014-01-01
Lunar floor-fractured craters are a class of craters modified by post-impact mechanisms. They are defined by distinctive shallow floors that are convex or plate-like, sometimes with a wide floor moat bordering the wall region. Radial, concentric, and polygonal floor fractures suggest an endogenous process of modification. Two mechanisms have been proposed to account for such deformations: viscous relaxation and spreading of a magma intrusion at depth below the crater. To test the second assumption and bring more constraints on the intrusion process, we develop a model for the dynamics of magma spreading below an elastic overlying layer with a crater-like topography. As predicted in earlier more qualitative studies, the increase in lithostatic pressure at the crater wall zone prevents the intrusion from spreading laterally, leading to the thickening of the intrusion. Additionally, our model shows that the final crater floor appearance after the uplift, which can be convex or flat, with or without a circular moat bordering the wall zone, depends on the elastic thickness of the layer overlying the intrusion and on the crater size. Our model provides a simple formula to derive the elastic thickness of the overlying layer hence a minimum estimate for the intrusion depth. Finally, our model suggests that crust redistribution by cratering must have controlled magma ascent below most of these craters.
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2004-01-01
23 March 2004 Craters of the martian northern plains tend to be somewhat shallow because material has filled them in. Their ejecta blankets, too, are often covered by younger materials. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example--a crater in Utopia Planitia near 43.7oN, 227.3oW. Erosion has roughened some of the surfaces of the material that filled the crater and covered its ejecta deposit. The picture covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.
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Update on Apollo Data Restoration by the NSSDC and the PDS Lunar Data Node
Williams, David R.; Hills, K. Kent; Taylor, Patrick T.; McBride, Marie J.; Guinness, Edward A.
2012-01-01
The Lunar Data Node (LDN) , under the auspices of the Geosciences Node of the Planetary Data System (PDS) and the National Space Science Data Center (NSSDC), is continuing its efforts to recover and restore Apollo science data. The data being restored are in large part archived with NSSDC on older media, but unarchived data are also being recovered from other sources. They are typically on 7- or 9-track magnetic tapes, often in obsolete formats, or held on microfilm, microfiche, or paper documents. The goal of the LDN is to restore these data from their current form, which is difficult for most researchers to access, into common digital formats with all necessary supporting data (metadata) and archive the data sets with PDS. Restoration involves reading the data from the original media, deciphering the data formats to produce readable digital data and converting the data into usable tabular formats. Each set of values in the table must then be understood in terms of the quantity measured and the units used. Information on instrument properties, operational history, and calibrations is gathered and added to the data set, along with pertinent references, contacts, and other ancillary documentation. The data set then undergoes a peer review and the final validated product is archived with PDS. Although much of this effort has concentrated on data archived at NSSDC in the 1970's, we have also recovered data and information that were never sent to NSSDC. These data, retrieved from various outside sources, include raw and reduced Gamma-Ray Spectrometer data from Apollos 15 and 16, information on the Apollo 17 Lunar Ejecta And Meteorites experiment, Dust Detector data from Apollos 11, 12, 14, and I5, raw telemetry tapes from the Apollo ALSEPs, and Weekly Status Reports for all the Apollo missions. These data are currently being read or organized, and supporting data is being gathered. We are still looking for the calibrated heat flow data from Apollos 15 and 17 for the
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Energy Technology Data Exchange (ETDEWEB)
Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.
1978-06-01
A computational approach used for subsurface explosion cratering was extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for the first computer simulation because it is one of the most thoroughly studied craters. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Initial conditions for this calculation included a meteorite impact velocity of 15 km/s, meteorite mass of 1.67 x 10/sup 8/ kg, with a corresponding kinetic energy of 1.88 x 10/sup 16/ J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation, a Tillotson equation-of-state description for iron and limestone was used with no shear strength. Results obtained for this preliminary calculation of the formation of Meteor Crater are in good agreement with field measurements. A color movie based on this calculation was produced using computer-generated graphics. 19 figures, 5 tables, 63 references.
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International Nuclear Information System (INIS)
Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.
1978-06-01
A computational approach used for subsurface explosion cratering was extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for the first computer simulation because it is one of the most thoroughly studied craters. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Initial conditions for this calculation included a meteorite impact velocity of 15 km/s, meteorite mass of 1.67 x 10 8 kg, with a corresponding kinetic energy of 1.88 x 10 16 J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation, a Tillotson equation-of-state description for iron and limestone was used with no shear strength. Results obtained for this preliminary calculation of the formation of Meteor Crater are in good agreement with field measurements. A color movie based on this calculation was produced using computer-generated graphics. 19 figures, 5 tables, 63 references
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FE-SEM, FIB and TEM Study of Surface Deposits of Apollo 15 Green Glass Volcanic Spherules
Ross, Daniel K.; Thomas-Keprta, K. L.; Rahman, Z.; Wentworth, S. J.; McKay, D. S.
2011-01-01
Surface deposits on lunar pyroclastic green (Apollo 15) and orange (Apollo 17) glass spherules have been attributed to condensation from the gas clouds that accompanied fire-fountain eruptions. The fire fountains cast molten lava high above the lunar surface and the silicate melt droplets quenched before landing producing the glass beads. Early investigations showed that these deposits are rich in sulfur and zinc. The deposits are extremely fine-grained and thin, so that it was never possible to determine their chemical compositions cleanly by SEM/EDX or electron probe x-ray analysis because most of the excited volume was in the under-lying silicate glass. We are investigating the surface deposits by TEM, using focused ion beam (FIB) microscopy to extract and thin the surface deposits. Here we report on chemical mapping of a FIB section of surface deposits of an Apollo green glass bead 15401using the ultra-high resolution JEOL 2500 STEM located at NASA Johnson Space Center.
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Matthews, John A.; Owen, Geraint; McEwen, Lindsey J.; Shakesby, Richard A.; Hill, Jennifer L.; Vater, Amber E.; Ratcliffe, Anna C.
2017-11-01
This regional inventory and study of a globally uncommon landform type reveals similarities in form and process between craters produced by snow-avalanche and meteorite impacts. Fifty-two snow-avalanche impact craters (mean diameter 85 m, range 10-185 m) were investigated through field research, aerial photographic interpretation and analysis of topographic maps. The craters are sited on valley bottoms or lake margins at the foot of steep avalanche paths (α = 28-59°), generally with an easterly aspect, where the slope of the final 200 m of the avalanche path (β) typically exceeds 15°. Crater diameter correlates with the area of the avalanche start zone, which points to snow-avalanche volume as the main control on crater size. Proximal erosional scars ('blast zones') up to 40 m high indicate up-range ejection of material from the crater, assisted by air-launch of the avalanches and impulse waves generated by their impact into water-filled craters. Formation of distal mounds up to 12 m high of variable shape is favoured by more dispersed down-range deposition of ejecta. Key to the development of snow-avalanche impact craters is the repeated occurrence of topographically-focused snow avalanches that impact with a steep angle on unconsolidated sediment. Secondary craters or pits, a few metres in diameter, are attributed to the impact of individual boulders or smaller bodies of snow ejected from the main avalanche. The process of crater formation by low-density, low-velocity, large-volume snow flows occurring as multiple events is broadly comparable with cratering by single-event, high-density, high-velocity, small-volume projectiles such as small meteorites. Simple comparative modelling of snow-avalanche events associated with a crater of average size (diameter 85 m) indicates that the kinetic energy of a single snow-avalanche impact event is two orders of magnitude less than that of a single meteorite-impact event capable of producing a crater of similar size
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Integration of Apollo Lunar Sample Data into Google Moon
Dawson, Melissa D.; Todd, Nancy S.; Lofgren, Gary
2010-01-01
The Google Moon Apollo Lunar Sample Data Integration project is a continuation of the Apollo 15 Google Moon Add-On project, which provides a scientific and educational tool for the study of the Moon and its geologic features. The main goal of this project is to provide a user-friendly interface for an interactive and educational outreach and learning tool for the Apollo missions. Specifically, this project?s focus is the dissemination of information about the lunar samples collected during the Apollo missions by providing any additional information needed to enhance the Apollo mission data on Google Moon. Apollo missions 15 and 16 were chosen to be completed first due to the availability of digitized lunar sample photographs and the amount of media associated with these missions. The user will be able to learn about the lunar samples collected in these Apollo missions, as well as see videos, pictures, and 360 degree panoramas of the lunar surface depicting the lunar samples in their natural state, following collection and during processing at NASA. Once completed, these interactive data layers will be submitted for inclusion into the Apollo 15 and 16 missions on Google Moon.
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International Nuclear Information System (INIS)
Bryan, J.B.; Burton, D.E.; Cunningham, M.E.; Lettis, L.A. Jr.
1978-04-01
A computational approach used for subsurface explosion cratering has been extended to hypervelocity impact cratering. Meteor (Barringer) Crater, Arizona, was selected for our first computer simulation because it was the most thoroughly studied. It is also an excellent example of a simple, bowl-shaped crater and is one of the youngest terrestrial impact craters. Shoemaker estimates that the impact occurred about 20,000 to 30,000 years ago [Roddy (1977)]. Initial conditions for this calculation included a meteorite impact velocity of 15 km/s. meteorite mass of 1.57E + 08 kg, with a corresponding kinetic energy of 1.88E + 16 J (4.5 megatons). A two-dimensional Eulerian finite difference code called SOIL was used for this simulation of a cylindrical iron projectile impacting at normal incidence into a limestone target. For this initial calculation a Tillotson equation-of-state description for iron and limestone was used with no shear strength. A color movie based on this calculation was produced using computer-generated graphics. Results obtained for this preliminary calculation of the formation of Meteor Crater, Arizona, are in good agreement with Meteor Crater Measurements
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2004-01-01
11 November 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image captures some of the complexity of the martian upper crust. Mars does not simply have an impact-cratered surface, it's upper crust is a cratered volume. Over time, older craters on Mars have been eroded, filled, buried, and in some cases exhumed and re-exposed at the martian surface. The crust of Mars is layered to depths of 10 or more kilometers, and mixed in with the layered bedrock are a variety of ancient craters with diameters ranging from a few tens of meters (a few tens of yards) to several hundred kilometers (more than one or two hundred miles). The picture shown here captures some of the essence of the layered, cratered volume of the upper crust of Mars in a very simple form. The image shows three distinct circular features. The smallest, in the lower right quarter of the image, is a meteor crater surrounded by a mound of material. This small crater formed within a layer of bedrock that once covered the entire scene, but today is found only in this small remnant adjacent to the crater. The intermediate-sized crater, west (left) of the small one, formed either in the next layer down--that is, below the layer in which the small crater formed--or it formed in some layers that are now removed, but was big enough to penetrate deeply into the rock that is near the surface today. The largest circular feature in the image, in the upper right quarter of the image, is still largely buried. It formed in layers of rock that are below the present surface. Erosion has brought traces of its rim back to the surface of Mars. This picture is located near 50.0oS, 77.8oW, and covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates this October 2004 image from the upper left.
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Woods, W David
2011-01-01
This new and expanded edition of the bestselling How Apollo Flew to the Moon tells the exciting story of how the Apollo missions were conducted and follows a virtual flight to the Moon and back. New material includes: - the exploration of the lunar surface; - more illustrations; - more technical explanations and anecdotes. From launch to splashdown, hitch a ride in the incredible Apollo spaceships, the most sophisticated machines of their time. Explore each step of the journey and glimpse the enormous range of disciplines, techniques, and procedures the Apollo crews had to master. Although the tremendous technological accomplishments are well documented, the human dimension is not forgotten, and the book calls on the testimony of the people who were there at the time. A wealth of fascinating and accessible material is provided, including: the role of the powerful Saturn V; the reasoning behind trajectories; the day-to-day concerns of human and spacecraft health; the triumphs and difficulties of working in...
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Stability of nuclear crater slopes in rock
International Nuclear Information System (INIS)
Fleming, Robert W.; Frandsen, Alton D.; LaFrenz, Robert L.
1970-01-01
The United States Army Engineer Nuclear Cratering Group was established in 1962 to participate with the Atomic Energy Commission in a joint research and development program to develop nuclear engineering and construction technology. A major part of this research effort has been devoted to studies of the engineering properties of craters. The program to date has included field investigations of crater properties in various media over a broad range of chemical and nuclear explosive yields, studies of man-made and natural slopes, and studies directed toward the development of analytical and empirical methods of crater stability analysis. From this background, a general understanding has been developed of the effects of a cratering explosion on the surrounding medium and of physical nature of the various crater zones which are produced. The stability of nuclear crater slopes has been a subject of prime interest in the feasibility study being conducted for an Atlantic-Pacific sea-level canal. Based on experimental evidence assembled to date, nuclear crater slopes in dry dock and dry alluvium have an initially stable configuration. There have been five nuclear craters produced to date with yields of 0.4 kt or more on which observations are based and the initial configurations of these craters have remained stable for over seven years. The medium, yield, crater dimensions, and date of event for these craters are summarized. It is interesting to note that the Sedan Crater has been subjected to strong seismic motions from nearby detonations without adverse effects
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Stability of nuclear crater slopes in rock
Energy Technology Data Exchange (ETDEWEB)
Fleming, Robert W; Frandsen, Alton D; LaFrenz, Robert L [U.S. Army Engineer Nuclear Cratering Group, Lawrence Radiation Laboratory, Livermore, CA (United States)
1970-05-15
The United States Army Engineer Nuclear Cratering Group was established in 1962 to participate with the Atomic Energy Commission in a joint research and development program to develop nuclear engineering and construction technology. A major part of this research effort has been devoted to studies of the engineering properties of craters. The program to date has included field investigations of crater properties in various media over a broad range of chemical and nuclear explosive yields, studies of man-made and natural slopes, and studies directed toward the development of analytical and empirical methods of crater stability analysis. From this background, a general understanding has been developed of the effects of a cratering explosion on the surrounding medium and of physical nature of the various crater zones which are produced. The stability of nuclear crater slopes has been a subject of prime interest in the feasibility study being conducted for an Atlantic-Pacific sea-level canal. Based on experimental evidence assembled to date, nuclear crater slopes in dry dock and dry alluvium have an initially stable configuration. There have been five nuclear craters produced to date with yields of 0.4 kt or more on which observations are based and the initial configurations of these craters have remained stable for over seven years. The medium, yield, crater dimensions, and date of event for these craters are summarized. It is interesting to note that the Sedan Crater has been subjected to strong seismic motions from nearby detonations without adverse effects.
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Myrabo, Leik N.; Smith, Wayne L. (Editor); Decusatis, Casimer; Frazier, Scott R.; Garrison, James L., Jr.; Meltzer, Jonathan S.; Minucci, Marco A.; Moder, Jeffrey P.; Morales, Ciro; Mueller, Mark T.
1988-01-01
This second year of the NASA/USRA-sponsored Advanced Aeronautical Design effort focused on systems integration and analysis of the Apollo Lightcraft. This beam-powered, single-stage-to-orbit vehicle is envisioned as the shuttlecraft of the 21st century. The five person vehicle was inspired largely by the Apollo Command Module, then reconfigured to include a new front seat with dual cockpit controls for the pilot and co-pilot, while still retaining the 3-abreast crew accommodations in the rear seat. The gross liftoff mass is 5550 kg, of which 500 kg is the payload and 300 kg is the LH2 propellant. The round trip cost to orbit is projected to be three orders of magnitude lower than the current space shuttle orbiter. The advanced laser-driven 5-speed combined-cycle engine has shiftpoints at Mach 1, 5, 11 and 25+. The Apollo Lightcraft can climb into low Earth orbit in three minutes, or fly to any spot on the globe in less than 45 minutes. Detailed investigations of the Apollo Lightcraft Project this second year further evolved the propulsion system design, while focusing on the following areas: (1) man/machine interface; (2) flight control systems; (3) power beaming system architecture; (4) re-entry aerodynamics; (5) shroud structural dynamics; and (6) optimal trajectory analysis. The principal new findings are documented. Advanced design efforts for the next academic year (1988/1989) will center on a one meter+ diameter spacecraft: the Lightcraft Technology Demonstrator (LTD). Detailed engineering design and analyses, as well as critical proof-of-concept experiments, will be carried out on this small, near-term machine. As presently conceived, the LTD could be constructed using state of the art components derived from existing liquid chemical rocket engine technology, advanced composite materials, and high power laser optics.
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Lindsay, Hamish
2001-01-01
This is perhaps the most complete, detailed and readable story of manned space-flight ever published Beginning with the historical origins of the dream of walking on the Moon, Tracking Apollo to the Moon is the complete story of manned spaceflight, from the earliest Mercury and Gemini flights through to the end of the Apollo era In readable, fascinating detail, Hamish Lindsay - who was directly involved in all three programs - chronicles mankind's greatest adventure with a great narrative, interviews, quotes and masses of photographs, including some previously unpublished As well as bringing the history of these missions to life Tracking Apollo to the Moon serves as a detailed reference for space enthusiasts and students Having seen the manuscript, the Smithsonian requested two copies of the finished book, and Buzz Aldrin asked for five!
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Mineralogy of Rocks and Sediments at Gale Crater, Mars
Achilles, Cherie; Downs, Robert; Blake, David; Vaniman, David; Ming, Doug; Rampe, Elizabeth; Morris, Dick; Morrison, Shaunna; Treiman, Allan; Chipera, Steve; Yen, Albert; Bristow, Thomas; Craig, Patricia; Hazen, Robert; Crisp, Joy; Grotzinger, John; Des Marias, David; Farmer, Jack; Sarrazin, Philippe; Morookian, John Michael
2017-04-01
The Mars Science Laboratory rover, Curiosity, is providing in situ mineralogical, geochemical, and sedimentological assessments of rocks and soils in Gale crater. Since landing in 2012, Curiosity has traveled over 15 km, providing analyses of mudstones and sandstones to build a stratigraphic history of the region. The CheMin X-ray diffraction (XRD) instrument is the first instrument on Mars to provide quantitative mineralogical analyses of drilled powders and scooped sediment based on X-ray crystallography. CheMin identifies and determines mineral abundances and unit-cell parameters of major crystalline phases, and identifies minor phases at abundances >1 wt%. In conjunction with elemental analyses, CheMin-derived crystal chemistry allows for the first calculations of crystalline and amorphous material compositions. These mineralogy, crystal chemistry, and amorphous chemistry datasets are playing central roles in the characterization of Gale crater paleoenvironments. CheMin has analyzed 17 rock and sediment samples. In the first phase of the mission, Curiosity explored the sedimentary units of Aeolis Palus (Bradbury group), including two mudstones from Yellowknife Bay. CheMin analyses of the Yellowknife Bay mudstones identified clay minerals among an overall basaltic mineral assemblage. These mineralogical results, along with imaging and geochemical analyses, were used to characterize an ancient lacustrine setting that is thought to have once been a habitable environment. Following the investigations of the Bradbury group, Curiosity arrived at the lower reaches of Aeolis Mons, commonly called Mt. Sharp. A strategic sample campaign was initiated, drilling bedrock at X-ray amorphous phases. Adjacent to fractures, light-toned, halo-like zones are thought to result from significant aqueous alteration of the primary sandstone and show decreased abundances of feldspar and pyroxene, and an increase in the amorphous component, specifically high-silica phases. The Murray
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Five Apollo astronauts with Lunar Module at ASVC prior to grand opening
1997-01-01
Some of the former Apollo program astronauts observe a Lunar Module and Moon mockup during a tour the new Apollo/Saturn V Center (ASVC) at KSC prior to the gala grand opening ceremony for the facility that was held Jan. 8, 1997. The astronauts were invited to participate in the event, which also featured NASA Administrator Dan Goldin and KSC Director Jay Honeycutt. Some of the visiting astonauts were (from left): Apollo 10 Lunar Module Pilot and Apollo 17 Commander Eugene A. Cernan; Apollo 9 Lunar Module Pilot Russell L. Schweikart; Apollo 10 Command Module Pilot and Apollo 16 Commander John W. Young; Apollo 10 Commander Thomas P. Stafford; and Apollo 11 Lunar Module Pilot Edwin E. 'Buzz' Aldrin, Jr. The ASVC also features several other Apollo program spacecraft components, multimedia presentations and a simulated Apollo/Saturn V liftoff. The facility will be a part of the KSC bus tour that embarks from the KSC Visitor Center.
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Crater Mound Formation by Wind Erosion on Mars
Steele, L. J.; Kite, E. S.; Michaels, T. I.
2018-01-01
Most of Mars' ancient sedimentary rocks by volume are in wind-eroded sedimentary mounds within impact craters and canyons, but the connections between mound form and wind erosion are unclear. We perform mesoscale simulations of different crater and mound morphologies to understand the formation of sedimentary mounds. As crater depth increases, slope winds produce increased erosion near the base of the crater wall, forming mounds. Peak erosion rates occur when the crater depth is ˜2 km. Mound evolution depends on the size of the host crater. In smaller craters mounds preferentially erode at the top, becoming more squat, while in larger craters mounds become steeper sided. This agrees with observations where smaller craters tend to have proportionally shorter mounds and larger craters have mounds encircled by moats. If a large-scale sedimentary layer blankets a crater, then as the layer recedes across the crater it will erode more toward the edges of the crater, resulting in a crescent-shaped moat. When a 160 km diameter mound-hosting crater is subject to a prevailing wind, the surface wind stress is stronger on the leeward side than on the windward side. This results in the center of the mound appearing to "march upwind" over time and forming a "bat-wing" shape, as is observed for Mount Sharp in Gale crater.
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Li, Bo; Ling, Zongcheng; Zhang, Jiang; Chen, Jian; Liu, ChangQing; Bi, Xiangyu
2018-02-01
Highland crater Lalande (4.45°S, 8.63°W; D = 23.4 km) is located on the PKT area of the lunar near side, southeast of the Mare Insularum. It is a complex crater in Copernican era and has three distinguishing features: high silicic anomaly, the highest Th abundance and special landforms on its floor. There are some low-relief bulges on the left of Lalande's floor with regular circle or ellipse shapes. They are ∼250-680 m wide and ∼30-91 m high with maximum flank slopes >20°. There are two possible scenarios for the formation of these low-relief bulges which are impact melt products or young silicic volcanic eruptions. We estimated the absolute model ages of the ejecta deposits, several melt ponds and the hummocky floor and determined the ratio of diameter and depth of the crater Lalande. In addition, we found some similar bugle features within other Copernican-aged craters and there were no volcanic source vents on Lalande's floor. Thus, we hypothesized that these low-relief bulges were most consistent with an origin of impact melts during the crater formation instead of small and young volcanic activities occurring on the floor. Based on Kaguya Terrain Camera (TC) ortho-mosaic and Digital Terrain Model (DTM) data produced by TC imagery in stereo, geological units and some linear features on the floor and wall of Lalande have been mapped. Eight geological units are organized by crater floor units: hummocky floor, central peak and low-relief bulges; and crater wall units: terraced walls, channeled and veneered walls, interior walls, mass wasting areas, blocky areas, and melt ponds. These geological units and linear features provided us a chance to understand some details of the cratering process and elevation differences on the floor. We proposed that subsidence due to melt cooling, late-stage wall collapse and rocks uplifted from beneath the surface could be the possible causes of the observed elevation differences on Lalande's floor.
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APOLLO 10 ASTRONAUT ENTERS LUNAR MODULE SIMULATOR
1969-01-01
Apollo 10 lunar module pilot Eugene A. Cernan prepares to enter the lunar module simulator at the Flight Crew Training Building at the NASA Spaceport. Cernan, Apollo 10 commander Thomas P. Stafford and John W. Young, command module pilot, are to be launched May 18 on the Apollo 10 mission, a dress rehearsal for a lunar landing later this summer. Cernan and Stafford are to detach the lunar module and drop to within 10 miles of the moon's surface before rejoining Young in the command/service module. Looking on as Cernan puts on his soft helmet is Snoopy, the lovable cartoon mutt whose name will be the lunar module code name during the Apollo 10 flight. The command/service module is to bear the code name Charlie Brown.
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What Really Happened to Earth's Older Craters?
Bottke, William; Mazrouei, Sara; Ghent, Rebecca; Parker, Alex
2017-10-01
Most assume the Earth’s crater record is heavily biased, with erosion/tectonics destroying older craters. This matches expectations, but is it actually true? To test this idea, we compared Earth’s crater record, where nearly all D ≥ 20 km craters are pick out from older craters with eroded fragments. Moreover, an inverse relationship between rock abundance (RA) and crater age exists. Using measured RA values, we computed ages for 111 rocky craters with D ≥ 10 km that formed between 80°N and 80°S over the last 1 Gyr.We found several surprising results. First, the production rate of D ≥ 10 km lunar craters increased by a factor of 2.2 [-0.9, +4.4; 95% confidence limits] over the past 250 Myr compared to the previous 750 Myr. Thus, the NEO population is higher now than it has been for the last billion years. Second, the size and age distributions of lunar and terrestrial craters for D ≥ 20 km over the last 650 Myr have similar shapes. This implies that crater erasure must be limited on stable terrestrial terrains; in an average sense, for a given region, the Earth either keeps all or loses all of its D ≥ 20 craters at the same rate, independent of size. It also implies the observed deficit of large terrestrial craters between 250-650 Myr is not preservation bias but rather reflects a distinctly lower impact flux. We predict 355 ± 86 D ≥ 20 km craters formed on Earth over the last 650 Myr. Only 38 ± 6 are known, so the ratio, 10.7 ± 3.1%, is a measure of the Earth’s surface that is reasonably stable to large crater formation over 650 Myr. If erosion had dominated, the age distribution of terrestrial craters would be strongly skewed toward younger ages, which is not observed. We predict Chicxulub-type impacts were rare over the last Gyr, with the event 66 Ma a probable byproduct of the current high terrestrial impact flux.
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Mineralogy of an active eolian sediment from the Namib dune, Gale crater, Mars
Achilles, C. N.; Downs, R. T.; Ming, D. W.; Rampe, E. B.; Morris, R. V.; Treiman, A. H.; Morrison, S. M.; Blake, D. F.; Vaniman, D. T.; Ewing, R. C.; Chipera, S. J.; Yen, A. S.; Bristow, T. F.; Ehlmann, B. L.; Gellert, R.; Hazen, R. M.; Fendrich, K. V.; Craig, P. I.; Grotzinger, J. P.; Des Marais, D. J.; Farmer, J. D.; Sarrazin, P. C.; Morookian, J. M.
2017-11-01
The Mars Science Laboratory rover, Curiosity, is using a comprehensive scientific payload to explore rocks and soils in Gale crater, Mars. Recent investigations of the Bagnold Dune Field provided the first in situ assessment of an active dune on Mars. The Chemistry and Mineralogy (CheMin) X-ray diffraction instrument on Curiosity performed quantitative mineralogical analyses of the history of the dune material and offers an important opportunity for ground truth of orbital observations. CheMin's analysis of the mineralogy and phase chemistry of modern and ancient Gale crater dune fields, together with other measurements by Curiosity's science payload, provides new insights into present and past eolian processes on Mars.
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Experimental simulation of impact cratering on icy satellites
Greeley, R.; Fink, J. H.; Gault, D. E.; Guest, J. E.
1982-01-01
Cratering processes on icy satellites were simulated in a series of 102 laboratory impact experiments involving a wide range of target materials. For impacts into homogeneous clay slurries with impact energies ranging from five million to ten billion ergs, target yield strengths ranged from 100 to 38 Pa, and apparent viscosities ranged from 8 to 200 Pa s. Bowl-shaped craters, flat-floored craters, central peak craters with high or little relief, and craters with no relief were observed. Crater diameters increased steadily as energies were raised. A similar sequence was seen for experiment in which impact energy was held constant but target viscosity and strength progressively decreases. The experiments suggest that the physical properties of the target media relative to the gravitationally induced stresses determined the final crater morphology. Crater palimpsests could form by prompt collapse of large central peak craters formed in low target strength materials. Ages estimated from crater size-frequency distributions that include these large craters may give values that are too high.
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Apollo 12 ropy glasses revisited
Wentworth, S. J.; Mckay, D. S.; Lindstrom, D. J.; Basu, A.; Martinez, R. R.; Bogard, D. D.; Garrison, D. H.
1994-01-01
We analyzed ropy glasses from Apollo 12 soils 12032 and 12033 by a variety of techniques including SEM/EDX, electron microprobe analysis, INAA, and Ar-39-Ar-40 age dating. The ropy glasses have potassium rare earth elements phosphorous (KREEP)-like compositions different from those of local Apollo 12 mare soils; it is likely that the ropy glasses are of exotic origin. Mixing calculations indicate that the ropy glasses formed from a liquid enriched in KREEP and that the ropy glass liquid also contained a significant amount of mare material. The presence of solar Ar and a trace of regolith-derived glass within the ropy glasses are evidence that the ropy glasses contain a small regolith component. Anorthosite and crystalline breccia (KREEP) clasts occur in some ropy glasses. We also found within these glasses clasts of felsite (fine-grained granitic fragments) very similar in texture and composition to the larger Apollo 12 felsites, which have a Ar-39-Ar-40 degassing age of 800 +/- 15 Ma. Measurements of 39-Ar-40-Ar in 12032 ropy glass indicate that it was degassed at the same time as the large felsite although the ropy glass was not completely degassed. The ropy glasses and felsites, therefore, probably came from the same source. Most early investigators suggested that the Apollo 12 ropy glasses were part of the ejecta deposited at the Apollo 12 site from the Copernicus impact. Our new data reinforce this model. If these ropy glasses are from Copernicus, they provide new clues to the nature of the target material at the Copernicus site, a part of the Moon that has not been sampled directly.
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Lunar Bouguer gravity anomalies - Imbrian age craters
Dvorak, J.; Phillips, R. J.
1978-01-01
The Bouguer gravity of mass anomalies associated with four Imbrian age craters, analyzed in the present paper, are found to differ considerably from the values of the mass anomalies associated with some young lunar craters. Of the Imbrian age craters, only Piccolomini exhibits a negative gravity anomaly (i.e., a low density region) which is characteristic of the young craters studied. The Bouguer gravity anomalies are zero for each of the remaining Imbrian age craters. Since, Piccolomini is younger, or at least less modified, than the other Imbrian age craters, it is suggested that the processes responsible for the post-impact modification of the Imbrian age craters may also be responsible for removing the negative mass anomalies initially associated with these features.
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Salamuniccar, Goran; Loncaric, Sven; Mazarico, Erwan Matias
2012-01-01
For Mars, 57,633 craters from the manually assembled catalogues and 72,668 additional craters identified using several crater detection algorithms (CDAs) have been merged into the MA130301GT catalogue. By contrast, for the Moon the most complete previous catalogue contains only 14,923 craters. Two recent missions provided higher-quality digital elevation maps (DEMs): SELENE (in 1/16° resolution) and Lunar Reconnaissance Orbiter (we used up to 1/512°). This was the main motivation for work on the new Crater Shape-based interpolation module, which improves previous CDA as follows: (1) it decreases the number of false-detections for the required number of true detections; (2) it improves detection capabilities for very small craters; and (3) it provides more accurate automated measurements of craters' properties. The results are: (1) LU60645GT, which is currently the most complete (up to D>=8 km) catalogue of Lunar craters; and (2) MA132843GT catalogue of Martian craters complete up to D>=2 km, which is the extension of the previous MA130301GT catalogue. As previously achieved for Mars, LU60645GT provides all properties that were provided by the previous Lunar catalogues, plus: (1) correlation between morphological descriptors from used catalogues; (2) correlation between manually assigned attributes and automated measurements; (3) average errors and their standard deviations for manually and automatically assigned attributes such as position coordinates, diameter, depth/diameter ratio, etc; and (4) a review of positional accuracy of used datasets. Additionally, surface dating could potentially be improved with the exhaustiveness of this new catalogue. The accompanying results are: (1) the possibility of comparing a large number of Lunar and Martian craters, of e.g. depth/diameter ratio and 2D profiles; (2) utilisation of a method for re-projection of datasets and catalogues, which is very useful for craters that are very close to poles; and (3) the extension of the
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International Nuclear Information System (INIS)
Meadows, J.
1979-01-01
The scientific value and importance of the Apollo lunar programme is assessed in the light of data obtained both from the lunar surface itself and also from the command modules which orbited above. It is stated that much of the material they returned still awaits a detailed examination and that the cooperative teams set up to handle the lunar material have established new methods and standards of analysis, which are currently revitalising the old science of meteoritics. The new forms of organised research have also been carried over in the rapidly developing subject of planetary science. It is concluded that whatever the motives for launching the Apollo missions, planetary scientists have been in a much better position to understand the Solar System since then. (UK)
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Regional chemical setting of the Apollo 16 landing site and the importance of the Kant Plateau
Andre, C. G.; El-Baz, F.
1982-01-01
Orbital X-ray data from the Apollo 16 region indicate that physiographic units identified before the lunar mission can be classified as chemical units as well. The Descartes Mountains, however, appear to be an extension of the Kant Plateau composition that is unusually anorthositic and resembles farside terra. The Cayley Plains have closer affinities to basaltic materials than terra materials, physically, spectrally and chemically. The Theophilus impact, 330 km east of the landing site, excavated magnesium-rich basalts from below less-magnesian flows in Mare Nectaris; but, mafic ejecta was substantially blocked from the Apollo 16 site by the Kant Plateau that rises 5 km above the level of the mare. Apollo 16 soil samples from stations selected to collect either Descartes Mountains material or Cayley Plains material were surprisingly similar. However, they do, indeed, show the chemical trends indicative of the two units as defined by the orbiting geochemistry detectors. The Kant Plateau and Descartes Mountains material may be among the rare nearside examples of a plagioclase-rich cumulate of the primordial magma ocean.
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Restoration of the Apollo Heat Flow Experiments Metadata
Nagihara, S.; Stephens, M. K.; Taylor, P. T.; Williams, D. R.; Hills, H. K.; Nakamura, Y.
2015-01-01
Geothermal heat flow probes were deployed on the Apollo 15 and 17 missions as part of the Apollo Lunar Surface Experiments Package (ALSEP). At each landing site, the astronauts drilled 2 holes, 10-m apart, and installed a probe in each. The holes were 1- and 1.5-m deep at the Apollo 15 site and 2.5-m deep at the Apollo 17 sites. The probes monitored surface temperature and subsurface temperatures at different depths. At the Apollo 15 site, the monitoring continued from July 1971 to January 1977. At the Apollo 17 site, it did from December 1972 to September 1977. Based on the observations made through December 1974, Marcus Langseth, the principal investigator of the heat flow experiments (HFE), determined the thermal conductivity of the lunar regolith by mathematically modeling how the seasonal temperature fluctuation propagated down through the regolith. He also determined the temperature unaffected by diurnal and seasonal thermal waves of the regolith at different depths, which yielded the geothermal gradient. By multiplying the thermal gradient and the thermal conductivity, Langseth obtained the endogenic heat flow of the Moon as 21 mW/m(exp 2) at Site 15 and 16 mW/m(exp 2) at Site 17.
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Neutron radiography of Apollo ordnance
International Nuclear Information System (INIS)
Golliher, K.G.
1983-01-01
Neutron radiography played an important role in the successful Apollo missions. Neutron radiography was used, for the first time, on a production basis to examine the internal details of ordnance devices employed in the Apollo Program. Ordnance devices ranged from charges which separated the massive booster stages to those which triggered the release of re-entry parachutes. Discussed are the early developments in neutron radiography and the conversion of this infant nondestructive technology into production capabilities. (Auth.)
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Machine cataloging of impact craters on Mars
Stepinski, Tomasz F.; Mendenhall, Michael P.; Bue, Brian D.
2009-09-01
This study presents an automated system for cataloging impact craters using the MOLA 128 pixels/degree digital elevation model of Mars. Craters are detected by a two-step algorithm that first identifies round and symmetric topographic depressions as crater candidates and then selects craters using a machine-learning technique. The system is robust with respect to surface types; craters are identified with similar accuracy from all different types of martian surfaces without adjusting input parameters. By using a large training set in its final selection step, the system produces virtually no false detections. Finally, the system provides a seamless integration of crater detection with its characterization. Of particular interest is the ability of our algorithm to calculate crater depths. The system is described and its application is demonstrated on eight large sites representing all major types of martian surfaces. An evaluation of its performance and prospects for its utilization for global surveys are given by means of detailed comparison of obtained results to the manually-derived Catalog of Large Martian Impact Craters. We use the results from the test sites to construct local depth-diameter relationships based on a large number of craters. In general, obtained relationships are in agreement with what was inferred on the basis of manual measurements. However, we have found that, in Terra Cimmeria, the depth/diameter ratio has an abrupt decrease at ˜38°S regardless of crater size. If shallowing of craters is attributed to presence of sub-surface ice, a sudden change in its spatial distribution is suggested by our findings.
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Nuclear cratering on a digital computer
International Nuclear Information System (INIS)
Terhune, R.W.; Stubbs, T.F.; Cherry, J.T.
1970-01-01
Computer programs based on the artificial viscosity method are applied to developing an understanding of the physics of cratering, with emphasis on cratering by nuclear explosives. Two established codes, SOC (spherical symmetry) and TENSOR (cylindrical symmetry), are used to illustrate the effects of variations in the material properties of various media on the cratering processes, namely shock, spall, and gas acceleration. Water content is found to be the most important material property, followed by strength, porosity, and compressibility. Crater profile calculations are presented for Pre-Gondola Charley (20-ton nitromethane detonation in shale) and Sedan (100-kt nuclear detonation in alluvium). Calculations also are presented for three 1-Mt yields in saturated Divide basalt and 1-Mt yield in dry Buckboard basalt, to show crater geometry as a function of the burial depth for large explosive yields. The calculations show, for megaton-level yields, that gas acceleration is the dominate mechanism in determining crater size and depends in turn on the water content in the medium. (author)
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Nuclear cratering on a digital computer
Energy Technology Data Exchange (ETDEWEB)
Terhune, R W; Stubbs, T F; Cherry, J T [Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)
1970-05-01
Computer programs based on the artificial viscosity method are applied to developing an understanding of the physics of cratering, with emphasis on cratering by nuclear explosives. Two established codes, SOC (spherical symmetry) and TENSOR (cylindrical symmetry), are used to illustrate the effects of variations in the material properties of various media on the cratering processes, namely shock, spall, and gas acceleration. Water content is found to be the most important material property, followed by strength, porosity, and compressibility. Crater profile calculations are presented for Pre-Gondola Charley (20-ton nitromethane detonation in shale) and Sedan (100-kt nuclear detonation in alluvium). Calculations also are presented for three 1-Mt yields in saturated Divide basalt and 1-Mt yield in dry Buckboard basalt, to show crater geometry as a function of the burial depth for large explosive yields. The calculations show, for megaton-level yields, that gas acceleration is the dominate mechanism in determining crater size and depends in turn on the water content in the medium. (author)
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NASA Administrator Dan Goldin greets Neil Armstrong at Apollo 11 anniversary banquet.
1999-01-01
During an anniversary banquet honoring the Apollo team, the people who made the entire lunar landing program possible, former Apollo astronaut Neil A. Armstrong (left) shakes the hand of Judy Goldin (center), wife of NASA Administrator Daniel S. Goldin (right). The banquet was held in the Apollo/Saturn V Center, part of the KSC Visitor Complex. This is the 30th anniversary of the Apollo 11 launch and moon landing, July 16 and July 20, 1969. Among the guests at the banquet were former Apollo astronauts are Neil A. Armstrong and Edwin 'Buzz' Aldrin who flew on Apollo 11, the launch of the first moon landing; Gene Cernan, who flew on Apollo 10 and 17 and was the last man to walk on the moon; and Walt Cunningham, who flew on Apollo 7.
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International Nuclear Information System (INIS)
Lapides, J.R.
1981-01-01
The gamma-ray spectroscopy of planet surfaces is one of several possible methods that are useful in determining the elemental composition of planet surfaces from orbiting spacecraft. This has been demonstrated on the Apollos 15 and 16 missions as well as the Soviet Mars-5 mission. Planetary gamma-ray emission is primarily the result of natural radioactive decay and cosmic-ray and solar-flare-induced nuclear reactions. Secondary neutron reactions play a large role in the more intense gamma-ray emission. The technique provides information on the elemental composition of the top few tens of centimeters of the planet surface. Varying concentrations of hydrogen and compositional variations that alter the macroscopic thermal-neutron absorption cross section have a significant effect on the neutron flux in the planet surface and therefore also on the gamma-ray emission from the surface. These effects have been systematically studied for a wide range of possible planetary compositions that include Mercury, the moon, Mars, the comets, and the asteroids. The problem of the Martian atmosphere was also investigated. The results of these calculations, in which both surface neutron fluxes and gamma-ray emission fluxes were determined, were used to develop general procedures for obtaining planet compositions from the gamma-ray spectrum. Several changes have been suggested for reanalyzing the Apollos 15 and 16 gamma-ray results. In addition, procedures have been suggested that can be applied to neutron-gamma techniques in mineral and oil exploration
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2003-01-01
MGS MOC Release No. MOC2-357, 11 May 2003This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows a pattern of polygons on the floor of a northern plains impact crater. These landforms are common on crater floors at high latitudes on Mars. Similar polygons occur in the arctic and antarctic regions of Earth, where they indicate the presence and freeze-thaw cycling of ground ice. Whether the polygons on Mars also indicate water ice in the ground is uncertain. The image is located in a crater at 64.8oN, 292.7oW. Sunlight illuminates the scene from the lower left.
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Floor-Fractured Craters through Machine Learning Methods
Thorey, C.
2015-12-01
Floor-fractured craters are impact craters that have undergone post impact deformations. They are characterized by shallow floors with a plate-like or convex appearance, wide floor moats, and radial, concentric, and polygonal floor-fractures. While the origin of these deformations has long been debated, it is now generally accepted that they are the result of the emplacement of shallow magmatic intrusions below their floor. These craters thus constitute an efficient tool to probe the importance of intrusive magmatism from the lunar surface. The most recent catalog of lunar-floor fractured craters references about 200 of them, mainly located around the lunar maria Herein, we will discuss the possibility of using machine learning algorithms to try to detect new floor-fractured craters on the Moon among the 60000 craters referenced in the most recent catalogs. In particular, we will use the gravity field provided by the Gravity Recovery and Interior Laboratory (GRAIL) mission, and the topographic dataset obtained from the Lunar Orbiter Laser Altimeter (LOLA) instrument to design a set of representative features for each crater. We will then discuss the possibility to design a binary supervised classifier, based on these features, to discriminate between the presence or absence of crater-centered intrusion below a specific crater. First predictions from different classifier in terms of their accuracy and uncertainty will be presented.
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Geology of Lofn Crater, Callisto
Greeley, Ronald; Heiner, Sarah; Klemaszewski, James E.
2001-01-01
Lofn crater is a 180-km-diameter impact structure in the southern cratered plains of Callisto and is among the youngest features seen on the surface. The Lofn area was imaged by the Galileo spacecraft at regional-scale resolutions (875 m/pixel), which enable the general geology to be investigated. The morphology of Lofn crater suggests that (1) it is a class of impact structure intermediate between complex craters and palimpsests or (2) it formed by the impact of a projectile which fragmented before reaching the surface, resulting in a shallow crater (even for Callisto). The asymmetric pattern of the rim and ejecta deposits suggests that the impactor entered at a low angle from the northwest. The albedo and other characteristics of the ejecta deposits from Lofn also provide insight into the properties of the icy lithosphere and subsurface configuration at the time of impact. The "target" for the Lofn impact is inferred to have included layered materials associated with the Adlinda multiring structure northwest of Loh and ejecta deposits from the Heimdall crater area to the southeast. The Lofn impact might have penetrated through these materials into a viscous substrate of ductile ice or possibly liquid water. This interpretation is consistent with models of the current interior of Callisto based on geophysical information obtained from the Galileo spacecraft.
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Restoration of Apollo Data by the NSSDC and the PDS Lunar Data Node
Williams, David R.; Hills, H. Kent; Lowman, Paul D.; Taylor, Patrick T.; Guinness, Edward A.
2011-01-01
The Lunar Data Node (LDN), under the auspices of the Geosciences Node of the Planetary Data System (PDS), is restoring Apollo data archived at the National Space Science Data Center. The Apollo data were arch ived on older media (7 -track tapes. microfilm, microfiche) and in ob solete digital formats, which limits use of the data. The LDN is maki ng these data accessible by restoring them to standard formats and archiving them through PDS. The restoration involves reading the older m edia, collecting supporting data (metadata), deciphering and understa nding the data, and organizing into a data set. The data undergo a pe er review before archive at PDS. We will give an update on last year' s work. We have scanned notebooks from Otto Berg, P.1. for the Lunar Ejecta and Meteorites Experiment. These notebooks contain information on the data and calibration coefficients which we hope to be able to use to restore the raw data into a usable archive. We have scanned Ap ollo 14 and 15 Dust Detector data from microfilm and are in the proce ss of archiving thc scans with PDS. We are also restoring raw dust de tector data from magnetic tape supplied by Yosio Nakamura (UT Austin) . Seiichi Nagihara (Texas Tech Univ.) and others in cooperation with NSSDC are recovering ARCSAV tapes (tapes containing raw data streams from all the ALSEP instruments). We will be preparing these data for archive with PDS. We are also in the process of recovering and archivi ng data not previously archived, from the Apollo 16 Gamma Ray Spectro meter and the Apollo 17 Infrared Spectrometer.
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Grant, J. A.; Schultz, P. H.
1991-01-01
Previous ground penetrating radar (GRP) studies around 50,000 year old Meteor Crater revealed the potential for rapid, inexpensive, and non-destructive sub-surface investigations for deep reflectors (generally greater than 10 m). New GRP results are summarized focusing the shallow sub-surfaces (1-2 m) around Meteor Crater and the main crater at Odessa. The following subject areas are covered: (1) the thickness, distribution, and nature of the contact between surrounding alluvial deposits and distal ejecta; and (2) stratigraphic relationships between both the ejecta and alluvium derived from both pre and post crater drainages. These results support previous conclusions indicating limited vertical lowering (less than 1 m) of the distal ejecta at Meteor Crater and allow initial assessment of the gradational state if the Odessa craters.
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Apollo Missions to the Lunar Surface
Graff, Paige V.
2018-01-01
Six Apollo missions to the Moon, from 1969-1972, enabled astronauts to collect and bring lunar rocks and materials from the lunar surface to Earth. Apollo lunar samples are curated by NASA Astromaterials at the NASA Johnson Space Center in Houston, TX. Samples continue to be studied and provide clues about our early Solar System. Learn more and view collected samples at: https://curator.jsc.nasa.gov/lunar.
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Low-velocity impact cratering experiments in granular slopes
Hayashi, Kosuke; Sumita, Ikuro
2017-07-01
Low-velocity impact cratering experiments are conducted in sloped granular targets to study the effect of the slope angle θ on the crater shape and its scales. We use two types of granular matter, sand and glass beads, former of which has a larger friction coefficient μs = tanθr , where θr is the angle of repose. Experiments show that as θ increases, the crater becomes shallower and elongated in the direction of the slope. Furthermore the crater floor steepens in the upslope side and a thick rim forms in the downslope side, thus forming an asymmetric profile. High-speed images show that these features are results of ejecta being dispersed farther towards the downslope side and the subsequent avalanche which buries much of the crater floor. Such asymmetric ejecta dispersal can be explained by combining the Z-model and a ballistic model. Using the topographic maps of the craters, we classify crater shape regimes I-III, which transition with increasing θ : a full-rim crater (I), a broken-rim crater (II), and a depression (III). The critical θ for the regime transitions are larger for sand compared to glass beads, but collapse to close values when we use a normalized slope θ^ = tanθ / tanθr . Similarly we derive θ^-dependences of the scaled crater depth, length, width and their ratios which collapse the results for different targets and impact energies. We compare the crater profiles formed in our experiments with deep craters on asteroid Vesta and find that some of the scaled profiles nearly overlap and many have similar depth / length ratios. This suggests that these Vestan craters may also have formed in the gravity regime and that the formation process can be approximated by a granular flow with a similar effective friction coefficient.
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Mineralogy of an Active Eolian Sediment from the Namib Dune, Gale Crater, Mars
Achilles, C. N.; Downs, R. T.; Ming, D. W.; Rampe, E. B.; Morris, R. V.; Treiman, A. H.; Morrison, S. M.; Blake, D. F.; Vaniman, D. T.; Ewing, R. C.; Chipera, S. J.; Yen, A. S.; Bristow, T. F.; Ehlmann, B. L.; Gellert, R.
2017-01-01
The Mars Science Laboratory rover, Curiosity, is using a comprehensive scientific payload to explore rocks and soils in Gale crater, Mars. Recent investigations of the Bagnold Dune Field provided the first in situ assessment of an active dune on Mars. The Chemistry and Mineralogy (CheMin) X-ray diffraction instrument on Curiosity performed quantitative mineralogical analyses of the
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On dislocation inhomogeneity of electroerosion crater zone in molybdenum single crystals
International Nuclear Information System (INIS)
Larikov, L.N.; Dubovitskaya, N.V.; Zakharov, S.M.
1979-01-01
Methods of diffraction electron microscopy, X-ray analysis and microhardness measurements have been applied to study the inhomogeneity of dislocation structure of the electroerosion crater zone in molybdenum single crystals. Microhardness inhomogeneous distribution in this zone is established, conditioned by changes in dislocation structure as a result of the development of thermally activated processes of the plastic deformation and dynamic recovery. Dislocationless channels are detected in predeformed crystals
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Moon - 'Ghost' craters formed during Mare filling.
Cruikshank, D. P.; Hartmann, W. K.; Wood, C. A.
1973-01-01
This paper discusses formation of 'pathological' cases of crater morphology due to interaction of craters with molten lavas. Terrestrial observations of such a process are discussed. In lunar maria, a number of small impact craters (D less than 10 km) may have been covered by thin layers of fluid lavas, or formed in molten lava. Some specific lunar examples are discussed, including unusual shallow rings resembling experimental craters deformed by isostatic filling.
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Investigations of Ceres's Craters with Straightened Rim
Frigeri, A.; De Sanctis, M. C.; Ammannito, E.; Raponi, A.; Formisano, M.; Ciarniello, M.; Magni, G.; Combe, J. P.; Marchi, S.; Raymond, C. A.; Schwartz, S. J.
2017-12-01
Dwarf planet Ceres hosts some geological features that are unique in the solar system because its composition, rich in aqueously-altered silicates, is usually found on full-size planets, whereas its mean radius is smaller than most natural satellites in the solar system. For example, the local high-albedo, carbonate-rich areas or faculaeare specific to Ceres; also, the absence of big impact crater structures is key to understand the overall mechanical behaviour of the Cerean crust. After the first findings of water ice occurring in the shadowed areas of craters on Ceres by the NASA/Dawn mission (1, 2), we analyzed the morphology of craters looking for features similar to the ones where the water ice composition has been detected analyzing the data from the VIR spectrometer (3). These craters fall outside of the family of polygonal craters which are mainly related to regional or global scale tectonics (4). We analyzed the morphology on the base of the global mosaic, the digital terrain model derived by using the stereo photogrammetry method and the single data frames of the Framing Camera. Our investigation started from crater Juling, which is characterized by a portion of the rim which forms a straight segment instead of a portion of a circle. This linear crater wall is also steep enough that it forms a cliff that is in the shadowed area in all images acquired by Dawn. Very smooth and bright deposits lay at the foot of this crater-wall cliff. Then, we identified several other craters, relatively fresh, with radius of 2 to 10 kilometers, showing one or two sectors of the crater-rim being truncated by a mass-wasting process, probably a rockfall. Our first analysis show that in the selected craters, the truncated sectors are always in the north-eastern sector of the rim for the craters in the southern hemisphere. Conversely, the craters on the northern hemisphere exhibit a truncated rim in their south-eastern sector. Although a more detailed analysis is mandatory
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Asteroid families from cratering: Detection and models
Milani, A.; Cellino, A.; Knežević, Z.; Novaković, B.; Spoto, F.; Paolicchi, P.
2014-07-01
A new asteroid families classification, more efficient in the inclusion of smaller family members, shows how relevant the cratering impacts are on large asteroids. These do not disrupt the target, but just form families with the ejecta from large craters. Of the 12 largest asteroids, 8 have cratering families: number (2), (4), (5), (10), (87), (15), (3), and (31). At least another 7 cratering families can be identified. Of the cratering families identified so far, 7 have >1000 members. This imposes a remarkable change from the focus on fragmentation families of previous classifications. Such a large dataset of asteroids believed to be crater ejecta opens a new challenge: to model the crater and family forming event(s) generating them. The first problem is to identify which cratering families, found by the similarity of proper elements, can be formed at once, with a single collision. We have identified as a likely outcome of multiple collisions the families of (4), (10), (15), and (20). Of the ejecta generated by cratering, only a fraction reaches the escape velocity from the surviving parent body. The distribution of velocities at infinity, giving to the resulting family an initial position and shape in the proper elements space, is highly asymmetric with respect to the parent body. This shape is deformed by the Yarkovsky effect and by the interaction with resonances. All the largest asteroids have been subjected to large cratering events, thus the lack of a family needs to be interpreted. The most interesting case is (1) Ceres, which is not the parent body of the nearby family of (93). Two possible interpretations of the low family forming efficiency are based on either the composition of Ceres with a significant fraction of ice, protected by a thin crust, or with the larger escape velocity of ~500 m/s.
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The Global Contribution of Secondary Craters on the Icy Satellites
Hoogenboom, T.; Johnson, K. E.; Schenk, P.
2014-12-01
At present, surface ages of bodies in the Outer Solar System are determined only from crater size-frequency distributions (a method dependent on an understanding of the projectile populations responsible for impact craters in these planetary systems). To derive accurate ages using impact craters, the impactor population must be understood. Impact craters in the Outer Solar System can be primary, secondary or sesquinary. The contribution of secondary craters to the overall population has recently become a "topic of interest." Our objective is to better understand the contribution of dispersed secondary craters to the small crater populations, and ultimately that of small comets to the projectile flux on icy satellites in general. We measure the diameters of obvious secondary craters (determined by e.g. irregular crater shape, small size, clustering) formed by all primary craters on Ganymede for which we have sufficiently high resolution data to map secondary craters. Primary craters mapped range from approximately 40 km to 210 km. Image resolution ranges from 45 to 440 m/pixel. Bright terrain on Ganymede is our primary focus. These resurfaced terrains have relatively low crater densities and serve as a basis for characterizing secondary populations as a function of primary size on an icy body for the first time. Although focusing on Ganymede, we also investigate secondary crater size, frequency, distribution, and formation, as well as secondary crater chain formation on icy satellites throughout the Saturnian and Jovian systems principally Rhea. We compare our results to similar studies of secondary cratering on the Moon and Mercury. Using Galileo and Voyager data, we have identified approximately 3,400 secondary craters on Ganymede. In some cases, we measured crater density as a function of distance from a primary crater. Because of the limitations of the Galileo data, it is necessary to extrapolate from small data sets to the global population of secondary craters
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Impact cratering experiments in Bingham materials and the morphology of craters on Mars and Ganymede
Fink, J. H.; Greeley, R.; Gault, D. E.
1982-01-01
Results from a series of laboratory impacts into clay slurry targets are compared with photographs of impact craters on Mars and Ganymede. The interior and ejecta lobe morphology of rampart-type craters, as well as the progression of crater forms seen with increasing diameter on both Mars and Ganymede, are equalitatively explained by a model for impact into Bingham materials. For increasing impact energies and constant target rheology, laboratory craters exhibit a morphologic progression from bowl-shaped forms that are typical of dry planetary surfaces to craters with ejecta flow lobes and decreasing interior relief, characteristic of more volatile-rich planets. A similar sequence is seen for uniform impact energy in slurries of decreasing yield strength. The planetary progressions are explained by assuming that volatile-rich or icy planetary surfaces behave locally in the same way as Bingham materials and produce ejecta slurries with yield strenghs and viscosities comparable to terrestrial debris flows. Hypothetical impact into Mars and Ganymede are compared, and it is concluded that less ejecta would be produced on Ganymede owing to its lower gravitational acceleration, surface temperature, and density of surface materials.
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Technical problems and future cratering experiments
Energy Technology Data Exchange (ETDEWEB)
Knox, J B [Lawrence Radiation Laboratory, Livermore, CA (United States)
1969-07-01
This paper reviews some of the key technical problems that remain to be solved in nuclear cratering technology. These include: (1) developing a broader understanding of the effects that material properties and water content of the earth materials around the shot have on cratering behavior, (2) extending the experimental investigation of retarc formation to include intermediate yields and various materials, and (3) improving our ability to predict the escape of radioactive material to the atmosphere to form the cloud source responsible for fallout. The formation processes of ejecta craters, retarcs, and subsidence craters are described in the light of our present understanding, and the major gaps in our understanding are indicated. Methods of calculating crater and retarc formation are discussed, with particular reference to the input information needed. Methods for calculating fallout are presented, and their shortcomings are discussed. A preliminary analysis of the safety factors associated with the presently proposed nuclear excavation concepts is presented. (author)
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Technical problems and future cratering experiments
International Nuclear Information System (INIS)
Knox, J.B.
1969-01-01
This paper reviews some of the key technical problems that remain to be solved in nuclear cratering technology. These include: (1) developing a broader understanding of the effects that material properties and water content of the earth materials around the shot have on cratering behavior, (2) extending the experimental investigation of retarc formation to include intermediate yields and various materials, and (3) improving our ability to predict the escape of radioactive material to the atmosphere to form the cloud source responsible for fallout. The formation processes of ejecta craters, retarcs, and subsidence craters are described in the light of our present understanding, and the major gaps in our understanding are indicated. Methods of calculating crater and retarc formation are discussed, with particular reference to the input information needed. Methods for calculating fallout are presented, and their shortcomings are discussed. A preliminary analysis of the safety factors associated with the presently proposed nuclear excavation concepts is presented. (author)
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Cratering statistics on asteroids: Methods and perspectives
Chapman, C.
2014-07-01
Crater size-frequency distributions (SFDs) on the surfaces of solid-surfaced bodies in the solar system have provided valuable insights about planetary surface processes and about impactor populations since the first spacecraft images were obtained in the 1960s. They can be used to determine relative age differences between surficial units, to obtain absolute model ages if the impactor flux and scaling laws are understood, to assess various endogenic planetary or asteroidal processes that degrade craters or resurface units, as well as assess changes in impactor populations across the solar system and/or with time. The first asteroid SFDs were measured from Galileo images of Gaspra and Ida (cf., Chapman 2002). Despite the superficial simplicity of these studies, they are fraught with many difficulties, including confusion by secondary and/or endogenic cratering and poorly understood aspects of varying target properties (including regoliths, ejecta blankets, and nearly-zero-g rubble piles), widely varying attributes of impactors, and a host of methodological problems including recognizability of degraded craters, which is affected by illumination angle and by the ''personal equations'' of analysts. Indeed, controlled studies (Robbins et al. 2014) demonstrate crater-density differences of a factor of two or more between experienced crater counters. These inherent difficulties have been especially apparent in divergent results for Vesta from different members of the Dawn Science Team (cf. Russell et al. 2013). Indeed, they have been exacerbated by misuse of a widely available tool (Craterstats: hrscview.fu- berlin.de/craterstats.html), which incorrectly computes error bars for proper interpretation of cumulative SFDs, resulting in derived model ages specified to three significant figures and interpretations of statistically insignificant kinks. They are further exacerbated, and for other small-body crater SFDs analyzed by the Berlin group, by stubbornly adopting
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Neil Armstrong chats with attendees at Apollo 11 anniversary banquet.
1999-01-01
Former Apollo 11 astronaut Neil A. Armstrong is the center of attention at the anniversary banquet honoring the Apollo team, the people who made the entire lunar landing program possible. The banquet was held in the Apollo/Saturn V Center, part of the KSC Visitor Complex. This is the 30th anniversary of the Apollo 11 launch and moon landing, July 16 and July 20, 1969. Neil Armstrong was the first man to set foot on the moon. He appeared at the banquet with other former astronauts Edwin 'Buzz' Aldrin, Gene Cernan, Walt Cunningham and others.
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The spectral code Apollo2: from lattice to 2D core calculations
International Nuclear Information System (INIS)
Coste-Delclaux, M.; Santandrea, S.; Damian, F.; Blanc-Tranchant, P.; Zmijarevic, I.; Santamarina, A.
2005-01-01
Apollo2 is a powerful code dedicated to neutron transport, it is a highly qualified tool for a wide range of applications from research and development studies to industrial applications. Today Apollo2 is part of several advanced 3-dimensional nuclear code packages dedicated to reactor physics, fuel cycle, criticality and safety analysis. The presentations have been organized into 7 topics: -) an introduction to Apollo2, -) cross-sections, -) flux calculation, -) advanced applications, -) Apollo2 users, specialized packages, -) qualification program, and -) the future of Apollo2. This document gathers only the slides of the presentations
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The spectral code Apollo2: from lattice to 2D core calculations
Energy Technology Data Exchange (ETDEWEB)
Coste-Delclaux, M.; Santandrea, S.; Damian, F.; Blanc-Tranchant, P.; Zmijarevic, I. [CEA Saclay (DEN/DANS/SERMA), 91 - Gif-sur-Yvette (France); Santamarina, A. [CEA Cadarache (CEA/DEN/DER/SPRC), 13 - Saint Paul lez Durance (France)
2005-07-01
Apollo2 is a powerful code dedicated to neutron transport, it is a highly qualified tool for a wide range of applications from research and development studies to industrial applications. Today Apollo2 is part of several advanced 3-dimensional nuclear code packages dedicated to reactor physics, fuel cycle, criticality and safety analysis. The presentations have been organized into 7 topics: -) an introduction to Apollo2, -) cross-sections, -) flux calculation, -) advanced applications, -) Apollo2 users, specialized packages, -) qualification program, and -) the future of Apollo2. This document gathers only the slides of the presentations.
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Kukkonen, S.; Kostama, V.-P.
2018-05-01
The availability of very high-resolution images has made it possible to extend crater size-frequency distribution studies to small, deca/hectometer-scale craters. This has enabled the dating of small and young surface units, as well as recent, short-time and small-scale geologic processes that have occurred on the units. Usually, however, the higher the spatial resolution of space images is, the smaller area is covered by the images. Thus the use of single, very high-resolution images in crater count age determination may be debatable if the images do not cover the studied region entirely. Here we compare the crater count results for the floor of the Harmakhis Vallis outflow channel obtained from the images of the ConTeXt camera (CTX) and High Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter (MRO). The CTX images enable crater counts for entire units on the Harmakhis Vallis main valley, whereas the coverage of the higher-resolution HiRISE images is limited and thus the images can only be used to date small parts of the units. Our case study shows that the crater count data based on small impact craters and small surface areas mainly correspond with the crater count data based on larger craters and more extensive counting areas on the same unit. If differences between the results were founded, they could usually be explained by the regional geology. Usually, these differences appeared when at least one cratering model age is missing from either of the crater datasets. On the other hand, we found only a few cases in which the cratering model ages were completely different. We conclude that the crater counts using small impact craters on small counting areas provide useful information about the geological processes which have modified the surface. However, it is important to remember that all the crater counts results obtained from a specific counting area always primarily represent the results from the counting area-not the whole
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Kenkmann, T.; Artemieva, N. A.; Wünnemann, K.; Poelchau, M. H.; Elbeshausen, D.; Núñez Del Prado, H.
2009-08-01
The recent Carancas meteorite impact event caused a worldwide sensation. An H4-5 chondrite struck the Earth south of Lake Titicaca in Peru on September 15, 2007, and formed a crater 14.2 m across. It is the smallest, youngest, and one of two eye-witnessed impact crater events on Earth. The impact violated the hitherto existing view that stony meteorites below a size of 100 m undergo major disruption and deceleration during their passage through the atmosphere and are not capable of producing craters. Fragmentation occurs if the strength of the meteoroid is less than the aerodynamic stresses that occur in flight. The small fragments that result from a breakup rain down at terminal velocity and are not capable of producing impact craters. The Carancas cratering event, however, demonstrates that meter-sized stony meteoroids indeed can survive the atmospheric passage under specific circumstances. We present results of a detailed geologic survey of the crater and its ejecta. To constrain the possible range of impact parameters we carried out numerical models of crater formation with the iSALE hydrocode in two and three dimensions. Depending on the strength properties of the target, the impact energies range between approximately 100-1000 MJ (0.024- 0.24 t TNT). By modeling the atmospheric traverse we demonstrate that low cosmic velocities (12- 14 kms-1) and shallow entry angles (<20°) are prerequisites to keep aerodynamic stresses low (<10 MPa) and thus to prevent fragmentation of stony meteoroids with standard strength properties. This scenario results in a strong meteoroid deceleration, a deflection of the trajectory to a steeper impact angle (40-60°), and an impact velocity of 350-600 ms-1, which is insufficient to produce a shock wave and significant shock effects in target minerals. Aerodynamic and crater modeling are consistent with field data and our microscopic inspection. However, these data are in conflict with trajectories inferred from the analysis of
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The Apollo lunar samples collection analysis and results
Young, Anthony
2017-01-01
This book focuses on the specific mission planning for lunar sample collection, the equipment used, and the analysis and findings concerning the samples at the Lunar Receiving Laboratory in Texas. Anthony Young documents the collection of Apollo samples for the first time for readers of all backgrounds, and includes interviews with many of those involved in planning and analyzing the samples. NASA contracted with the U.S. Geologic Survey to perform classroom and field training of the Apollo astronauts. NASA’s Geology Group within the Manned Spacecraft Center in Houston, Texas, helped to establish the goals of sample collection, as well as the design of sample collection tools, bags, and storage containers. In this book, detailed descriptions are given on the design of the lunar sampling tools, the Modular Experiment Transporter used on Apollo 14, and the specific areas of the Lunar Rover vehicle used for the Apollo 15, 16, and 17 missions, which carried the sampling tools, bags, and other related equipment ...
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PDS Lunar Data Node Restoration of Apollo In-Situ Surface Data
Williams, David R.; Hills, H. Kent; Guinness, Edward A.; Lowman, Paul D.; Taylor, Patrick T.
2010-01-01
The Apollo missions between 1969 and 1972 deployed scientific instruments on the Moon's surface which made in-situ measurements of the lunar environment. Apollo II had the short-term Early Apollo Surface Experiments Package (EASEP) and Apollos 12, 14, 15, 16, and 17 each set up an Apollo Lunar Surface Experiments Package (ALSEP). Each ALSEP package contained a different suite of instruments which took measurements and radioed the results back to Earth over periods from 5 to 7 years until they were turned off on 30 September 1977. To this day the ALSEP data remain the only long-term in-situ information on the Moon's surface environment. The Lunar Data Node (LDN) has been formed under the auspices of the Planetary Data System (PDS) Geosciences Node to put relevant, scientifically important Apollo data into accessible digital form for use by researchers and mission planners. We will report on progress made since last year and plans for future data restorations.
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Brueckner, J.
2004-05-01
The new Alpha Particle X-Ray Spectrometer (APXS) is a small, light-weight instrument to obtain x-ray spectra from Martian surface samples. The sensor head contains a high-resolution x-ray detector that is surrounded by a circle of radioactive Cm-244 sources. Alpha and x-ray radiation emitted by the sources is used to induce x-ray excitation in the sample. Elements from sodium to zinc (increasing by atomic weight) are detected and their concentrations determined. The APXS is mounted on each Instrument Deployment Device (IDD) of the two Mars Exploration Rovers (MER) Spirit and Opportunity. Rover Spirit landed in the large Gusev crater that seems to have been altered by water activities in the past based on evidence of orbital images. Rover Opportunity landed in a very small crater of the Meridiani Planum, where the mineral hematite that points to water-related processes is expected to be found. Inside the little crater, a light-colored outcrop is exposed that shows widespread fine layering. The first APXS high-resolution x-ray spectrum of a Gusev soil indicated many similarities to the composition of the Mars Pathfinder (MPF) and Viking soils. However, differences are also noticeable: Low-Z elements are somewhat higher compared to MPF soils, while high-Z elements are depleted, notably Ti. Potassium in the soils reflects the K concentration of the local rocks at the different landing sites pointing toward a local contribution to the soil's composition. The Rock Abrasion Tool was used to grind the first rock on Mars at Gusev: Adirondack's undisturbed and ground surface was measured by the APXS. The composition of its fresh surface is different from the MPF soilfree rock, noticeably in Mg and Al, and clearly exhibits a basaltic nature related to the composition of basaltic shergottites. The first rock at the Meridiani crater outcrop (dubbed Robert-E) exhibited a very high sulfur concentration, more than a factor of 15 compared to rock Adirondack, indicating it is
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Apollo lugejate lemmikraamatud
2006-01-01
Apollo kaupluse koduleheküljel valiti parimaks ilukirjandusteoseks Jan Kausi "Tema", tõlgitud ilukirjanduse osas David Mitchelli "Pilveatlas", luuleraamatutest Ott Arderi "Luule sünnib kus sünnib kui sünnib" ja lasteraamatutest Christopher Paolini "Vanem". Vt. ka SL Õhtuleht, 14. dets., lk. 13
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Physics analysis of the Apollo D-3He tokamak reactor
International Nuclear Information System (INIS)
Santarius, J.F.; Emmert, G.A.
1990-01-01
Recent developments in the analysis and conceptual design of Apollo, a D- 3 He Tokamak Reactor are presented. Encouraging experimental results on TEXT motivated a key change in the Apollo concept utilization of an ergodic magnetic limiter for impurity control instead of a divertor. Parameters for the updated Apollo design and an analysis of the ergoidc magnetic limiter are given. The Apollo reference case uses direct conversion of synchrotron radiation to electricity by rectifying antennas (rectennas) for its power conversion system. Previous analyses of this concept are expanded, including further details of the rectennas and of the loss of synchrotron power to the waveguides and walls. Although Apollo will burn D- 3 He fuel, a significant amount of unburned tritium will be generated by D4D reactions. The possibility of operating a short, dedicated, T+ 3 He burn phase to eliminate this tritium will be examined
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Comparison between KARBUS and APOLLO 1; Vergleichsrechnungen mit KARBUS und APOLLO 1
Energy Technology Data Exchange (ETDEWEB)
Payer, L.; Broeders, C.
1995-08-01
A comparison is made between benchmark calculations by the French APOLLO 1 code and the Karlsruhe KARBUS procedure. Independently these two codes had been developed for transport computations in infinite reactor configurations and for burnup calculations. (orig.)
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Determining long-term regional erosion rates using impact craters
Hergarten, Stefan; Kenkmann, Thomas
2015-04-01
More than 300,000 impact craters have been found on Mars, while the surface of Moon's highlands is even saturated with craters. In contrast, only 184 impact craters have been confirmed on Earth so far with only 125 of them exposed at the surface. The spatial distribution of these impact craters is highly inhomogeneous. Beside the large variation in the age of the crust, consumption of craters by erosion and burial by sediments are the main actors being responsible for the quite small and inhomogeneous crater record. In this study we present a novel approach to infer long-term average erosion rates at regional scales from the terrestrial crater inventory. The basic idea behind this approach is a dynamic equilibrium between the production of new craters and their consumption by erosion. It is assumed that each crater remains detectable until the total erosion after the impact exceeds a characteristic depth depending on the crater's diameter. Combining this model with the terrestrial crater production rate, i.e., the number of craters per unit area and time as a function of their diameter, allows for a prediction of the expected number of craters in a given region as a function of the erosion rate. Using the real crater inventory, this relationship can be inverted to determine the regional long-term erosion rate and its statistical uncertainty. A limitation by the finite age of the crust can also be taken into account. Applying the method to the Colorado Plateau and the Deccan Traps, both being regions with a distinct geological history, yields erosion rates in excellent agreement with those obtained by other, more laborious methods. However, these rates are formally exposed to large statistical uncertainties due to the small number of impact craters. As higher crater densities are related to lower erosion rates, smaller statistical errors can be expected when large regions in old parts of the crust are considered. Very low long-term erosion rates of less than 4
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Investigation of Secondary Craters in the Saturnian System
Hoogenboom, T.; Schenk, P.; White, O. L.
2012-03-01
To derive accurate ages using impact craters, the impact source must be determined. We investigate secondary crater size, frequency, distribution, formation, and crater chain formation on icy satellites throughout the Jupiter and Saturn systems.
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Murdin, P.
2000-11-01
(the Cup; abbrev. Crt, gen. Crateris; area 282 sq. deg.) A southern constellation which lies to the south-west of Virgo, and culminates at midnight in mid-March. It represents the cup of the god Apollo in Greek mythology (see Corvus). Its brightest stars were cataloged by Ptolemy (c. AD 100-175) in the Almagest....
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Apollo 15 mare units and their petrogenesis
International Nuclear Information System (INIS)
Binder, A.A.
1985-01-01
Samples from 12 different mare sites were identified and classified among the Apollo 15 samples. The genesis of the Apollo 15 mare units is summarized given the general model of mare basalt source regions and of more basalt genesis derived from a synthesis of the major oxide/major mineral, compatible siderophile, and incompatible trace element data and isotopic ratios of the Rb/Sr and Sm/Nd systems
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Pancam Peek into 'Victoria Crater' (Stereo)
2006-01-01
[figure removed for brevity, see original site] Left-eye view of a stereo pair for PIA08776 [figure removed for brevity, see original site] Right-eye view of a stereo pair for PIA08776 A drive of about 60 meters (about 200 feet) on the 943rd Martian day, or sol, of Opportunity's exploration of Mars' Meridiani Planum region (Sept. 18, 2006) brought the NASA rover to within about 50 meters (about 160 feet) of the rim of 'Victoria Crater.' This crater has been the mission's long-term destination for the past 21 Earth months. Opportunity reached a location from which the cameras on top of the rover's mast could begin to see into the interior of Victoria. This stereo anaglyph was made from frames taken on sol 943 by the panoramic camera (Pancam) to offer a three-dimensional view when seen through red-blue glasses. It shows the upper portion of interior crater walls facing toward Opportunity from up to about 850 meters (half a mile) away. The amount of vertical relief visible at the top of the interior walls from this angle is about 15 meters (about 50 feet). The exposures were taken through a Pancam filter selecting wavelengths centered on 750 nanometers. Victoria Crater is about five times wider than 'Endurance Crater,' which Opportunity spent six months examining in 2004, and about 40 times wider than 'Eagle Crater,' where Opportunity first landed. The great lure of Victoria is the expectation that a thick stack of geological layers will be exposed in the crater walls, potentially several times the thickness that was previously studied at Endurance and therefore, potentially preserving several times the historical record.
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A schematic model of crater modification by gravity
Melosh, H. J.
1982-01-01
The morphology of craters found on planets and moons of the solar system is examined and a development model which can account for the observed crater characteristics is discussed. The prompt collapse of craters to form flat floors, terraced walls, and central peak structures is considered to be the result of an approximate Bingham plastic rheology of the material surrounding the crater. This rheology is induced dynamically by the strong incoherent acoustic 'noise' accompanying excavation of the crater. Central pits, peak rings, and other multiple symmetric-profile rings originate by oscillation of this fluid. Large craters with transient depths comparable to the lithosphere thickness are subject to collapse by fragmentation of the lithosphere as well as fluidization. The considered concepts are developed mathematically. A model emerges which appears capable of explaining most of the qualitative features of large impact structures.
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Morphometry and Morphology of Fresh Craters on Titan
Kirk, R. L.; Wood, C. A.; Neish, C.; Lucas, A.; Hayes, A. G.; Cassini Radar Team
2011-12-01
Cassini RADAR imagery obtained on Titan flyby T77 revealed a 40-km diameter fresh impact crater at 11.6° N 44.6° W. This is only the 8th crater identified with high confidence (Wood et al., 2010, Icarus 206, 334), and the 3rd (after Sinlap D=79 km and Ksa D=30 km) for which the depth can be estimated by comparing the foreshortening of the near and far walls. This "autostereo" technique yields an estimated depth of 680 m. The T77 image forms a stereo pair with the T17 discovery image of Ksa from which we estimate the depth of Ksa at 750-800 m, in close agreement with SARTopo data. The depth of Sinlap is 760 m based on SARTopo. Depth-diameter ratios for these craters thus range from 0.01 to 0.025 and the depths are comparable to but 200-400 m shallower than fresh craters of the same size on Ganymede (Bray et al., 2008, Met. Planet Sci. 43, 1979). The depth differences could be explained by initial crater morphometry, by relaxation in a different thermal environment, or (perhaps most plausibly given the bland floors of even the freshest Titan craters) to sedimentary infill. In contrast, the 18x36 km elliptical depression at Sotra Facula is much deeper than Ganymede craters of similar size (d=1500 m from stereo), supporting the conclusion that it is not an impact crater. All three craters exhibit a relatively radar-bright annulus around the outer edge of the floor, possibly as the result of mass wasting of blocky materials from the crater walls. The central part of each crater is darker. The central darker floor of the new crater is symmetrical and featureless, whereas Ksa has a bright central ring 7 km in diameter. Stereo spot heights indicate the ring is 350±100 m above the outer floor. This height is in close agreement with the scaling for Ganymede crater central peaks from Bray et al. (2008). The darker floor area of Sinlap is substantially asymmetrical with a small bright central spot whose elevation is unknown. The new crater has continuous, radar
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Crater topography on Titan: Implications for landscape evolution
Neish, C.; Kirk, R.; Lorenz, R.; Bray, V.; Schenk, P.; Stiles, B.; Turtle, E.; Cassini Radar Team
2012-04-01
Unique among the icy satellites, Titan’s surface shows evidence for extensive modification by fluvial and aeolian erosion, which act to change the topography of its surface over time. Quantifying the extent of this landscape evolution is difficult, since the original, ‘non-eroded’ surface topography is generally unknown. However, fresh craters on icy satellites have a well-known shape and morphology, which has been determined from extensive studies on the airless worlds of the outer solar system (Schenk et al., 2004). By comparing the topography of craters on Titan to similarly sized, pristine analogues on airless bodies, we can obtain one of the few direct measures of the amount of erosion that has occurred on Titan. Cassini RADAR has imaged >30% of the surface of Titan, and more than 60 potential craters have been identified in this data set (Wood et al., 2010; Neish and Lorenz, 2012). Topographic information for these craters can be obtained from a technique known as ‘SARTopo’, which estimates surface heights by comparing the calibration of overlapping synthetic aperture radar (SAR) beams (Stiles et al., 2009). We present topography data for several craters on Titan, and compare the data to similarly sized craters on Ganymede, for which topography has been extracted from stereo-derived digital elevation models (Bray et al., 2012). We find that the depths of craters on Titan are generally within the range of depths observed on Ganymede, but several hundreds of meters shallower than the average (Fig. 1). A statistical comparison between the two data sets suggests that it is extremely unlikely that Titan’s craters were selected from the depth distribution of fresh craters on Ganymede, and that is it much more probable that the relative depths of Titan are uniformly distributed between ‘fresh’ and ‘completely infilled’. This is consistent with an infilling process that varies linearly with time, such as aeolian infilling. Figure 1: Depth of
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Detection of lunar floor-fractured craters using machine learning methods
Thorey, C.
2015-10-01
About 200 Floor Fractured Craters (FFCs) have been identified by Schultz (1976) on the Moon, mainly around the lunar maria. These craters are a class of impact craters that are distinguished by having radi-ally and concentric floor-fractured networks and ab-normally shallow floors. In some cases, the uplift of the crater floor can be as large as 50% of the initial crater depth. These impact craters are interpreted to have undergone endogenous deformations after their formation.
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Simple Impact Crater Shapes From Shadows - The Sequel
Chappelow, J. E.
2008-12-01
At the last LPSC meeting I presented the outline of a method for determining simple impact crater shapes from shadows. In theory the shadow cast within a simple crater provides enough information to derive its cross-sectional shape from shadow measurements, at least to the maximum depth to which the shadow extends. Under certain simple assumptions, this can be done analytically. If the crater is conic-section - shaped, then it can be shown that the down-sun bound of any shadow cast within it is elliptical, with one axis along the direction of illumination and the other (perpendicular to it) of semi-length D/2 (where D is diameter). The properties of this shadow-ellipse can be related to the parameters of the crater shape conic-section, thus measurements of the shadow-ellipse yield not only crater depth and diameter but also the approximate crater shape, in terms of conic sections. The method also does not depend upon the shadow crossing near the crater center, which avoids a pitfall of older shadow measurement methods. The technique is also amenable to computer implementation, which has already been largely completed. Once computerized, crater measurements can be made rapidly and repeatably. The program reads in an image, its resolution, and the solar elevation and azimuth. The user then defines the crater rim by 'clicking' on three points, and the shadow ellipse by clicking on two more. The program calculates and outputs the diameter, the depth, and parameters describing the crater's approximating conic-section. It is highly applicable to situations where only single-image photography is available, for example MESSENGER flybys of Mercury. At the meeting I will present the finished math for this method and give some examples of its use.
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Neakrase, L. D.; Lim, D. S. S.; Haberle, C. W.; Hughes, S. S.; Kobs-Nawotniak, S. E.; Christensen, P. R.
2016-12-01
Idaho's Eastern Snake River Plain (ESRP) is host to extensive expressions of basaltic volcanism dominated by non evolved olivine tholeiites (NEOT) with localized occurrences of evolved lavas. Craters of the Moon National Monument (COTM) is a polygenetic lava field comprised of more than 60 lava flows emplaced during 8 eruptive periods spanning the last 15 kyrs. The most recent eruptive period (period A; 2500-2000 yr B.P.) produced flows with total alkali vs. silica classifications spanning basalt to trachyte. Coeval with the emplacement of the COTM period A volcanic pile was the emplacement of the Wapi and King's Bowl NEOT 70 km SSE of COTM along the Great Rift. Previous investigations have determined a genetic link between these two compositionally distinct volcanic centers where COTM compositions can be generated from NEOT melts through complex ascent paths and variable degrees of fractionation and assimilation of lower-middle crustal materials. The Mars Exploration Rover, Spirit, conducted a robotic investigation of Gusev crater from 2004-2010. Spirit was equipped with the Athena science payload enabling the determination of mineralogy (mini-Thermal Emission Spectrometer, Pancam multispectral camera, and Mössbauer spectrometer), bulk chemistry (Alpha Particle X-ray Spectrometer) and context (Pancam and Microscopic Imager). During sol 32 Spirit investigated an olivine basalt named Adirondack, the type specimen for a class of rock that composes much of the plains material within Gusev Crater and embays the Columbia Hills. Following the characterization of the plains material, Spirit departed the plains targeting the Columbia Hills and ascending at Husband Hill. During Spirit's ascent of Husband Hill three additional classes of volcanic rock were identified as distinct by their mini-TES spectra; Wishstone, Backstay and Irvine. These rocks are classified as tephrite, trachy-basalt and basalt, respectively, and are the first alkaline rocks observed on Mars. These
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Apollo 12 - On the Ocean of Storms
Harland, David
2011-01-01
With its two moonwalks, deployment of a geophysical station and geological sampling, Apollo 12 did what many had hoped would be achieved by the first men to land on the Moon. It spectacularly demonstrated the precision landing capability required for the success of future lunar surface explorations. Apollo 12 - On the Ocean of Storms contains over 30 page of color images, including high-resolution scans recently produced by NASA from the original Hasselblad film; covers the mission from its planning through to completion; includes conversations among the crew in the spacecraft that were not transmitted; in the definitive 'popular' account of this mission. This is the first time in 40 years that the story of the Apollo 12 mission to the Moon has bene told in its entirety, using official documents, flight transcripts, and post-mission debriefing to recreate the drama.
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Neil Armstrong gets round of applaus at Apollo 11 anniversary banquet.
1999-01-01
Former Apollo 11 astronaut Neil A. Armstrong stands to a round of applause after being introduced at the anniversary banquet honoring the Apollo team, the people who made the entire lunar landing program possible. The banquet was held in the Apollo/Saturn V Center, part of the KSC Visitor Complex. This is the 30th anniversary of the Apollo 11 launch and moon landing, July 16 and July 20, 1969. Neil Armstrong was the first man to set foot on the moon. He appeared at the banquet with other former astronauts Edwin 'Buzz' Aldrin, Gene Cernan, Walt Cunningham and others.
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The link between aerospace industry and NASA during the Apollo years
Turcat, Nicolas
2008-01-01
Made in the frame of a French master on political history of USA in Paris IV La Sorbonne University, this subject is the third part of " The Economy of Apollo during the 60s". Nicolas Turcat is actually preparing his PhD in History of Innovation (DEA—Paris IV La Sorbonne). Our actual subject is " the link between aerospace industry and NASA during the Apollo years". This speech will highlight on some aspects of the link between NASA and aerospace industry. NASA could achieve the Apollo mission safely and under heavy financial pressure during the sixties due to a new type of organization for a civil agency; the contractor system. In fact, Military used it since the 1950s. And we will see how the development of this type of contract permitted a better interaction between the two parts. NASA would make another type of link with universities and technical institutes; a real brain trust was created, and between 1961 and 1967, 10,000 students worked and more than 200 universities on Apollo program. We will try to study briefly the procurement plan and process during the Apollo years. Without entering the " spin-offs debate", we will try to watch different aspects of the impacts and realities of the contractor and subcontractor system. We will see that would create a political debate inside USA when presidents Johnson and Nixon would decide to reduce Apollo program. Which states will benefit Apollo program? Or questions like how the debate at the end of the 1960s will become more and more political? Actually, almost 60% of the country's R&D was focused on Apollo, economical and moreover, political impacts would be great. We will try to study this under the light of different example: and particularly in California. The industrial and military complex was a part of the Apollo program. Apollo reoriented the aim of this complex for making it the first aerospace industry. Since this time, USA had not only acquired space ambition but real space capabilities. But more than
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Official emblem of the Apollo Soyuz Test Project
1974-01-01
This is the Official emblem of the Apollo Soyuz Test Project (ASTP) chosen by NASA and the Soviet Academy of Sciences. Of circular design, the emblem has the words Apollo in English and Soyuz in Russian around a center disc which depicts the two spacecraft docked together in Earth orbit. The Russian word 'soyuz' means 'union' in English.
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Shallow and deep fresh impact craters in Hesperia Planum, Mars
Mouginis-Mark, Peter J.; Hayashi, Joan N.
1993-01-01
The depths of 109 impact craters about 2-16 km in diameter, located on the ridged plains materials of Hesperia Planum, Mars, have been measured from their shadow lengths using digital Viking Orbiter images (orbit numbers 417S-419S) and the PICS computer software. On the basis of their pristine morphology (very fresh lobate ejecta blankets, well preserved rim crests, and lack of superposed impact craters), 57 of these craters have been selected for detailed analysis of their spatial distribution and geometry. We find that south of 30 deg S, craters less than 6.0 km in diameter are markedly shallower than similar-sized craters equatorward of this latitude. No comparable relationship is observed for morphologically fresh craters greater than 6.0 km diameter. We also find that two populations exist for older craters less than 6.0 km diameter. When craters that lack ejecta blankets are grouped on the basis of depth/diameter ratio, the deeper craters also typically lie equatorward of 30 S. We interpret the spatial variation in crater depth/diameter ratios as most likely due to a poleward increase in volatiles within the top 400 m of the surface at the times these craters were formed.
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Coesite from Wabar crater, near Al Hadida, Arabia
Chao, E.C.T.; Fahey, J.J.; Littler, J.
1961-01-01
The third natural occurrence of coesite, the high pressure polymorph of silica, is found at the Wabar meteorite crater, Arabia. The Wabar crater is about 300 feet in diameter and about 40 feet deep. It is the smallest of three craters where coesite has been found.
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Curiosity at Gale Crater, Mars: Characterization and Analysis of the Rocknest Sand Shadow
Blake, David F.; Morris, Richard V.; Kocurek, G.; Morrison, S. M.; Downs, R. T.; Bish, D.; Ming, D. W.; Edgett, K. S.; Rubin, D.; Goetz, W.;
2013-01-01
The Rocknest aeolian deposit is similar to aeolian features analyzed by the Mars Exploration Rovers (MER) Spirit and Opportunity. The fraction of sand <150 micron in size contains approx. 55% crystalline material consistent with a basaltic heritage, and approx. 45% X-ray amorphous material. The amorphous component of Rocknest is Fe-rich and Si-poor, and is the host of the volatiles (H2O, O2, SO2, CO2, and Cl) detected by the Surface Analysis at Mars (SAM) instrument and of the fine-grained nanophase oxide (npOx) component first described from basaltic soils analyzed by MER. The similarity between soils and aeolian materials analyzed at Gusev crater, Meridiani Planum and Gale crater implies locally sourced, globally similar basaltic materials, or globally and regionally sourced basaltic components deposited locally at all three locations.
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Optimizing laser crater enhanced Raman scattering spectroscopy
Lednev, V. N.; Sdvizhenskii, P. A.; Grishin, M. Ya.; Fedorov, A. N.; Khokhlova, O. V.; Oshurko, V. B.; Pershin, S. M.
2018-05-01
The laser crater enhanced Raman scattering (LCERS) spectroscopy technique has been systematically studied for chosen sampling strategy and influence of powder material properties on spectra intensity enhancement. The same nanosecond pulsed solid state Nd:YAG laser (532 nm, 10 ns, 0.1-1.5 mJ/pulse) was used for laser crater production and Raman scattering experiments for L-aspartic acid powder. Increased sampling area inside crater cavity is the key factor for Raman signal improvement for the LCERS technique, thus Raman signal enhancement was studied as a function of numerous experimental parameters including lens-to-sample distance, wavelength (532 and 1064 nm) and laser pulse energy utilized for crater production. Combining laser pulses of 1064 and 532 nm wavelengths for crater ablation was shown to be an effective way for additional LCERS signal improvement. Powder material properties (particle size distribution, powder compactness) were demonstrated to affect LCERS measurements with better results achieved for smaller particles and lower compactness.
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Hailar crater - A possible impact structure in Inner Mongolia, China
Xiao, Zhiyong; Chen, Zhaoxu; Pu, Jiang; Xiao, Xiao; Wang, Yichen; Huang, Jun
2018-04-01
Hailar crater, a probable impact structure, is a circular depression about 300 m diameter in Inner Mongolia, northeast China. With broad elevated rims, the present rim-to-floor depth is 8-20 m. Regional geological background and geomorphological comparison suggest that this feature is likely not formed by surface processes such as salt diapir, karst, aeolian, glacial, or volcanic activity. Its unique occurrence in this region and well-preserved morphology are most consistent with it being a Cenozoic impact crater. Two field expeditions in 2016 and 2017 investigated the origin of this structure, recognizing that (1) no additional craters were identified around Hailar crater in the centimeter-scale digital topography models that were constructed using a drone imaging system and stereo photogrammetry; (2) no bedrock exposures are visible within or adjacent to the crater because of thick regolith coverage, and only small pieces of angular unconsolidated rocks are present on the crater wall and the gently-sloped crater rim, suggesting recent energetic formation of the crater; (3) most samples collected from the crater have identical lithology and petrographic characteristics with the background terrain, but some crater samples contain more abundant clasts and silicate hydrothermal veins, indicating that rocks from depths have been exposed by the crater; (4) no shock metamorphic features were found in the samples after thin section examinations; and (5) a systematic sample survey and iron detector scan within and outside of the crater found no iron-rich meteorites larger than 2 cm in size in a depth of 30 cm. Although no conclusive evidence for an impact origin is found yet, Hailar crater was most likely formed by an impact based on its unique occurrence and comparative geomorphologic study. We suggest that drilling in the crater center is required to verify the impact origin, where hypothesized melt-bearing impactites may be encountered.
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3D structure of the Gusev Crater region
van Kan - Parker, M.; Zegers, T.E.; kneissl, T.; Ivanov, B.; Neukum, G.; Foing, B.
2010-01-01
Gusev Crater lies within the Aeolis Quadrangle of Mars at the boundary between the northern lowlands and southern highlands. The ancient valley Ma'adim Vallis dissects the highlands south of Gusev Crater and is thought to have fed the crater with sediments.High Resolution Stereo Camera data and
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Crater ejecta scaling laws: fundamental forms based on dimensional analysis
International Nuclear Information System (INIS)
Housen, K.R.; Schmidt, R.M.; Holsapple, K.A.
1983-01-01
A model of crater ejecta is constructed using dimensional analysis and a recently developed theory of energy and momentum coupling in cratering events. General relations are derived that provide a rationale for scaling laboratory measurements of ejecta to larger events. Specific expressions are presented for ejection velocities and ejecta blanket profiles in two limiting regimes of crater formation: the so-called gravity and strength regimes. In the gravity regime, ejectra velocities at geometrically similar launch points within craters vary as the square root of the product of crater radius and gravity. This relation implies geometric similarity of ejecta blankets. That is, the thickness of an ejecta blanket as a function of distance from the crater center is the same for all sizes of craters if the thickness and range are expressed in terms of crater radii. In the strength regime, ejecta velocities are independent of crater size. Consequently, ejecta blankets are not geometrically similar in this regime. For points away from the crater rim the expressions for ejecta velocities and thickness take the form of power laws. The exponents in these power laws are functions of an exponent, α, that appears in crater radius scaling relations. Thus experimental studies of the dependence of crater radius on impact conditions determine scaling relations for ejecta. Predicted ejection velocities and ejecta-blanket profiles, based on measured values of α, are compared to existing measurements of velocities and debris profiles
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Irons, Trevor P.; Martin, Kathryn; Finn, Carol A.; Bloss, Benjamin; Horton, Robert J.
2014-01-01
Surface and laboratory Nuclear Magnetic Resonance (NMR) measurements combined with transient electromagnetic (TEM) data are powerful tools for subsurface water detection. Surface NMR (sNMR) and TEM soundings, laboratory NMR, complex resistivity, and X-Ray Diffraction (XRD) analysis were all conducted to characterise the distribution of water within Sherman Crater on Mt. Baker, WA. Clay rich rocks, particularly if water saturated, can weaken volcanoes, thereby increasing the potential for catastrophic sector collapses that can lead to far-travelled, destructive debris flows. Detecting the presence and volume of shallow groundwater is critical for evaluating these landslide hazards. The TEM data identified a low resistivity layer (conditions which would allow for sNMR detection of the clay layer are investigated. Using current instrumentation the combined analysis of the TEM and sNMR data allow for valuable characterisation of the groundwater system in the crater. The sNMR is able to reduce the uncertainty of the TEM in regards to the presence of a bulk water layer, a valuable piece of information in hazard assessment.
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Ralston, S. J.; Hausrath, E. M.; Tschauner, O.; Rampe, E. B.; Christoffersen, R.
2018-01-01
Investigations with the CheMin Xray Diffractometer (XRD) onboard the Curiosity rover in Gale Crater demonstrate that all rock and soil samples measured to date contain approximately 15-70 weight percentage X-ray amorphous materials. The diffuse scattering hump from the X-ray amorphous materials in CheMin XRD patterns can be fit with a combination of allophane, ferrihydrite, and rhyolitic and basaltic glass. Because of the iron-rich nature of Mars' surface, Fe-rich poorly-crystalline phases, such as hisingerite, may be present in addition to allophane.
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Apollo Saturn V Height Comparison to Statue of Liberty
1967-01-01
This 1967 illustration compares the Apollo Saturn V Spacecraft of the Moon Landing era to the Statue of Liberty located on Ellis Island in New York City. The Apollo Saturn V, at 363 feet towers above Lady Liberty, as the statue is called, standing at 305 feet.
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1970-01-01
This is the Apollo 14 crew patch. It features the astronaut lapel pin approaching the Moon and leaving a comet trail from the liftoff point on Earth. The pin design was adopted by the astronaut corps several years ago. Astronauts who have not yet flown in space wear silver pins. Those who have flown wear gold pins.
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Apollo 7 prime crew during water egress training in Gulf of Mexico
1968-01-01
The prime crew of the first manned Apollo space mission, Apollo 7, is seen in Apollo Command Module Boilerplate 1102 during water egress training in the Gulf of Mexico. In foreground is Astronaut Walter M. Schirra Jr., in center is Astronaut Donn F. Eisele, and in background is Astronaut Walter Cunningham.
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Crater Topography on Titan: Implications for Landscape Evolution
Neish, Catherine D.; Kirk, R.L.; Lorenz, R. D.; Bray, V. J.; Schenk, P.; Stiles, B. W.; Turtle, E.; Mitchell, K.; Hayes, A.
2013-01-01
We present a comprehensive review of available crater topography measurements for Saturn's moon Titan. In general, the depths of Titan's craters are within the range of depths observed for similarly sized fresh craters on Ganymede, but several hundreds of meters shallower than Ganymede's average depth vs. diameter trend. Depth-to-diameter ratios are between 0.0012 +/- 0.0003 (for the largest crater studied, Menrva, D approximately 425 km) and 0.017 +/- 0.004 (for the smallest crater studied, Ksa, D approximately 39 km). When we evaluate the Anderson-Darling goodness-of-fit parameter, we find that there is less than a 10% probability that Titan's craters have a current depth distribution that is consistent with the depth distribution of fresh craters on Ganymede. There is, however, a much higher probability that the relative depths are uniformly distributed between 0 (fresh) and 1 (completely infilled). This distribution is consistent with an infilling process that is relatively constant with time, such as aeolian deposition. Assuming that Ganymede represents a close 'airless' analogue to Titan, the difference in depths represents the first quantitative measure of the amount of modification that has shaped Titan's surface, the only body in the outer Solar System with extensive surface-atmosphere exchange.
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High Resolution Digital Elevation Models of Pristine Explosion Craters
Farr, T. G.; Krabill, W.; Garvin, J. B.
2004-01-01
In order to effectively capture a realistic terrain applicable to studies of cratering processes and landing hazards on Mars, we have obtained high resolution digital elevation models of several pristine explosion craters at the Nevada Test Site. We used the Airborne Terrain Mapper (ATM), operated by NASA's Wallops Flight Facility to obtain DEMs with 1 m spacing and 10 cm vertical errors of 4 main craters and many other craters and collapse pits. The main craters that were mapped are Sedan, Scooter, Schooner, and Danny Boy. The 370 m diameter Sedan crater, located on Yucca Flat, is the largest and freshest explosion crater on Earth that was formed under conditions similar to hypervelocity impact cratering. As such, it is effectively pristine, having been formed in 1962 as a result of a controlled detonation of a 100 kiloton thermonuclear device, buried at the appropriate equivalent depth of burst required to make a simple crater. Sedan was formed in alluvium of mixed lithology and subsequently studied using a variety of field-based methods. Nearby secondary craters were also formed at the time and were also mapped by ATM. Adjacent to Sedan and also in alluvium is Scooter, about 90 m in diameter and formed by a high-explosive event. Schooner (240 m) and Danny Boy (80 m) craters were also important targets for ATM as they were excavated in hard basalt and therefore have much rougher ejecta. This will allow study of ejecta patterns in hard rock as well as engineering tests of crater and rock avoidance and rover trafficability. In addition to the high resolution DEMs, crater geometric characteristics, RMS roughness maps, and other higher-order derived data products will be generated using these data. These will provide constraints for models of landing hazards on Mars and for rover trafficability. Other planned studies will include ejecta size-frequency distribution at the resolution of the DEM and at finer resolution through air photography and field measurements
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Geologic map of Tooting crater, Amazonis Planitia region of Mars
Mouginis-Mark, Peter J.
2015-01-01
Tooting crater has a diameter of 27.2 km, and formed on virtually flat lava flows within Amazonis Planitia ~1,300 km west of the summit of Olympus Mons volcano, where there appear to have been no other major topographic features prior to the impact. The crater formed in an area ~185 x 135 km that is at an elevation between −3,870 m and −3,874 m relative to the Mars Orbiter Laser Altimeter (MOLA) Mars datum. This fortuitous situation (for example, a bland, horizontal target) allows the geometry of the crater and the thickness of the ejecta blanket to be accurately determined by subtracting the appropriate elevation of the surrounding landscape (−3,872 m) from the individual MOLA measurements across the crater. Thus, for the first time, it is possible to determine the radial decrease of ejecta thickness as a function of distance away from the rim crest. On the basis of the four discrete ejecta layers surrounding the crater cavity, Tooting crater is classified as a Multiple-Layered Ejecta (MLE) crater. By virtue of the asymmetric distribution of secondary craters and the greater thickness of ejecta to the northeast, Morris and others (2010) proposed that Tooting crater formed by an oblique impact from the southwest. The maximum range of blocks that produced identifiable secondary craters is ~500 km (~36.0 crater radii) from the northeast rim crest. In contrast, secondary craters are only identifiable ~215 km (15.8 radii) to the southeast and 225 km (16.5 radii) to the west.
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Emblem of the Apollo 17 lunar landing mission
1972-01-01
This is the Official emblem of the Apollo 17 lunar landing mission which will be flown by Astronauts Eugene A. Cernan, Ronald E. Evans and Harrison H. Schmitt. The insignia is dominated by the image of Apollo, the Greek sun god. Suspended in space behind the head of Apollo is an American eagle of contemporary design, the red bars of the eagle's wing represent the bars in the U.S. flag; the three white stars symbolize the three astronaut crewmen. The background is deep blue space and within it are the Moon, the planet Saturn and a spiral galaxy or nebula. The Moon is partially overlaid by the eagle's wing suggesting that this is a celestial body that man has visited and in that sense conquered. The thrust of the eagle and the gaze of Apollo to the right and toward Saturn and the galaxy is meant to imply that man's goals in space will someday include the planets and perhaps the stars. The colors of the emblem are red, white and blue, the colors of our flag; with the addition of gold, to
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Rock and Roll at the Apollo 17 Site
Martel, L. M. V.
2016-06-01
Astronauts Eugene A. Cernan and Harrison H. (Jack) Schmitt collected 243 pounds (110 kg) of rock and regolith samples during 22 hours working on the lunar surface during the Apollo 17 mission in December 1972, while Astronaut Ronald Evans orbited in the command module. The field observations, audio descriptions, and photographs coupled with orbital data and detailed, laboratory analyses of Apollo samples provided unprecedented information about the Moon and its geologic history. The Apollo samples continue to inspire new questions and answers about the Moon. Debra Hurwitz and David Kring (Lunar and Planetary Institute and NASA Solar System Exploration Research Virtual Institute; Hurwitz now at NASA Goddard Space Flight Center) were particularly interested in solving the mystery of where the boulders came from at the base of the North Massif (station 6) and at the base of the South Massif (station 2) from which Apollo 17 astronauts collected samples of impact melt breccias. The breccias were unequivocally formed by impact processes, but forty years of analyses had not yet determined unambiguously which impact event was responsible. Was it the basin-forming event of the landing site's neighbor Serenitatis (possibly Nectarian age); the larger, nearby Imbrium basin (Imbrian age and one of the last large basins to form); a combination of these impacts or an impact event older or younger than all of the above. Tracking down the origin of the boulders would ideally unravel details of the formation age of the breccias and, ultimately, help with the historical record of basin formation on the Moon. Hurwitz and Kring verified the boulders rolled down from massif walls - Apollo 17 impact melt breccias originated in massif material, not from the Sculptured Hills, an overlying geologic unit. But the relative geologic context is easier to explain than the absolute age, at least until some discrepancies are resolved in existing Ar-Ar and U-Pb radiometric ages of the Apollo 17
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1969-01-01
The crowning achievement for the Saturn V rocket came when it launched Apollo 11 astronauts, Neil Armstrong, Edwin (Buzz) Aldrin, and Michael Collins, to the Moon in July 1969. In this photograph, astronaut Aldrin takes his first step onto the surface of the Moon.
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Optimizing laser crater enhanced Raman spectroscopy.
Lednev, V N; Sdvizhenskii, P A; Grishin, M Ya; Filichkina, V A; Shchegolikhin, A N; Pershin, S M
2018-03-20
Raman signal enhancement by laser crater production was systematically studied for 785 nm continuous wave laser pumping. Laser craters were produced in L-aspartic acid powder by a nanosecond pulsed solid state neodymium-doped yttrium aluminum garnet laser (532 nm, 8 ns, 1 mJ/pulse), while Raman spectra were then acquired by using a commercial spectrometer with 785 nm laser beam pumping. The Raman signal enhancement effect was studied in terms of the number of ablating pulses used, the lens-to-sample distance, and the crater-center-laser-spot offset. The influence of the experiment parameters on Raman signal enhancement was studied for different powder materials. Maximum Raman signal enhancement reached 11 fold for loose powders but decreased twice for pressed tablets. Raman signal enhancement was demonstrated for several diverse powder materials like gypsum or ammonium nitrate with better results achieved for the samples tending to give narrow and deep craters upon the laser ablation stage. Alternative ways of cavity production (steel needle tapping and hole drilling) were compared with the laser cratering technique in terms of Raman signal enhancement. Drilling was found to give the poorest enhancement of the Raman signal, while both laser ablation and steel needle tapping provided comparable results. Here, we have demonstrated for the first time, to the best of our knowledge, that a Raman signal can be enhanced 10 fold with the aid of simple cavity production by steel needle tapping in rough highly reflective materials. Though laser crater enhancement Raman spectroscopy requires an additional pulsed laser, this technique is more appropriate for automatization compared to the needle tapping approach.
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APOLLO 16 COMMANDER JOHN YOUNG ENTERS ALTITUDE CHAMBER FOR TESTS
1971-01-01
Apollo 16 commander John W. Young prepares to enter the lunar module in an altitude chamber in the Manned Spacecraft Operations Building at the spaceport prior to an altitude run. During the altitude run, in which Apollo 16 lunar module pilot Charles M. Duke also participated, the chamber was pumped down to simulate pressure at an altitude in excess of 200,000 feet. Young, Duke and command module pilot Thomas K. Mattingly II, are training at the Kennedy Space Center for the Apollo 16 mission. Launch is scheduled from Pad 39A, March 17, 1972.
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Apollo, Marsyas and Ferdinand I
Czech Academy of Sciences Publication Activity Database
Bažant, Jan
2009-01-01
Roč. 2007, č. 22 (2009), s. 127-136 ISSN 0567-8269 Institutional research plan: CEZ:AV0Z90090514 Keywords : Apollo * Marsyas * Ferdinand I * Prague * Renaissance Subject RIV: AA - Philosophy ; Religion
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Review of measurements of dust movements on the Moon during Apollo
O'Brien, Brian J.
2011-11-01
This is the first review of 3 Apollo experiments, which made the only direct measurements of dust on the lunar surface: (i) minimalist matchbox-sized 270 g Dust Detector Experiments (DDEs) of Apollo 11, 12, 14 and 15, produced 30 million Lunar Day measurements 21 July 1969-30 September, 1977; (ii) Thermal Degradation Samples (TDS) of Apollo 14, sprinkled with dust, photographed, taken back to Earth into quarantine and lost; and (iii) the 7.5 kg Lunar Ejecta and Meteoroids (LEAM) experiment of Apollo 17, whose original tapes and plots are lost. LEAM, designed to measure rare impacts of cosmic dust, registered scores of events each lunation most frequently around sunrise and sunset. LEAM data are accepted as caused by heavily-charged particles of lunar dust at speeds of motivation for returning to the Moon. New analyses here show some raw data are sporadic bursts of 1, 2, 3 or more events within time bubbles smaller than 0.6 s, not predicted by theoretical dust models but consistent with noise bits caused by electromagnetic interference (EMI) from switching of large currents in the Apollo 17 Lunar Surface Experiment Package (ALSEP), as occurred in pre-flight LEAM-acceptance tests. On the Moon switching is most common around sunrise and sunset in a dozen heavy-duty heaters essential for operational survival during 350 h of lunar night temperatures of minus 170 °C. Another four otherwise unexplained features of LEAM data are consistent with the "noise bits" hypothesis. Discoveries with DDE and TDS reported in 1970 and 1971, though overlooked, and extensive DDE discoveries in 2009 revealed strengths of adhesive and cohesive forces of lunar dust. Rocket exhaust gases during Lunar Module (LM) ascent caused dust and debris to (i) contaminate instruments 17 m distant (Apollo 11) as expected, and (ii) unexpectedly cleanse Apollo hardware 130 m (Apollo 12) and 180 m (Apollo 14) from LM. TDS photos uniquely document in situ cohesion of dust particles and their adhesion to 12
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Medical microbiological analysis of Apollo-Soyuz test project crewmembers
Taylor, G. R.; Zaloguev, S. N.
1976-01-01
The procedures and results of the Microbial Exchange Experiment (AR-002) of the Apollo-Soyuz Test Project are described. Included in the discussion of procedural aspects are methods and materials, in-flight microbial specimen collection, and preliminary analysis of microbial specimens. Medically important microorganisms recovered from both Apollo and Soyuz crewmen are evaluated.
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Apollo 11 Earth Training Exercises
1969-01-01
In preparation of the nation's first lunar landing mission, Apollo 11 crew members underwent training to practice activities they would be performing during the mission. In this photograph, taken at the Manned Spacecraft Center in Houston, Texas, an engineer, Bob Mason, donned in a space suit, goes through some of those training exercises on the mock lunar surface. He performed activites similar to those planned for astronauts Neil Armstrong and Edwin Aldrin during their moon walk. The Apollo 11 mission launched from the Kennedy Space Center (KSC) in Florida via the Marshall Space Flight Center (MSFC) developed Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. Aboard the space craft were astronauts Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. (Buzz) Aldrin Jr., Lunar Module (LM) pilot. The CM, 'Columbia', piloted by Collins, remained in a parking orbit around the Moon while the LM, 'Eagle'', carrying astronauts Armstrong and Aldrin, landed on the Moon. On July 20, 1969, Armstrong was the first human to ever stand on the lunar surface, followed by Aldrin. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. With the success of Apollo 11, the national objective to land men on the Moon and return them safely to Earth had been accomplished.
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Indigenous Carbon Embedded in Apollo 17 Black Volcanic Glass Surface Deposits
Thomas-Keprta, Kathie L.; Ross, D. K.; Le, L.; Gonzalez, C.; McKay, D. S.; Gibson, E. K.
2012-01-01
The assessment of indigenous organic matter in returned lunar samples was one of the primary scientific goals of the Apollo program. The levels of such organic material were expected to be and found to be small. Previous work on this topic includes Murphy et al. [1] who reported the presence of anthropogenic organics with sub-ppm concentrations in Apollo 11 fines. In Apollo 12 samples, Preti et al. [2] detected low levels, < 10 ppb or below, of more complex organic material that may have been synthesized by abrupt heating during analysis. Kvenvolden et al. [3] detected porphyrin-like pigments at the ng to pg level in an Apollo 11 bulk sample. Hodgson et al. [4] and Ponnamperuma et al. [5] suggested that most if not all porphyrins were synthesized from rocket fuel during module landing. Chang et al. [6] reported indigenous carbon ranging from 5-20 g/g in the form of metal carbides in Apollo 11 fines. Hare et al. [7] reported amino acids at he 50 ng/g level in Apollo 11 samples but suggested the results may be explained as contamination. More recently, Clemett et al. [8] reported simple polycyclic aromatic hydrocarbons at concentrations of < 1ppm in an Apollo 16 soil. Low concentrations of lunar organics may be a consequence not only of its paucity, but also its heterogeneous distribution. If the sample size required for a measurement is large relative to the localization of organics, detection is limited not by ultimate sensitivity but rather by the ability to distinguish an indigenous signature from background contamination [9].
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Apollo Lunar Sample Integration into Google Moon: A New Approach to Digitization
Dawson, Melissa D.; Todd, nancy S.; Lofgren, Gary E.
2011-01-01
The Google Moon Apollo Lunar Sample Data Integration project is part of a larger, LASER-funded 4-year lunar rock photo restoration project by NASA s Acquisition and Curation Office [1]. The objective of this project is to enhance the Apollo mission data already available on Google Moon with information about the lunar samples collected during the Apollo missions. To this end, we have combined rock sample data from various sources, including Curation databases, mission documentation and lunar sample catalogs, with newly available digital photography of rock samples to create a user-friendly, interactive tool for learning about the Apollo Moon samples
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Fa, Wenzhe; Liu, Tiantian; Zhu, Meng-Hua; Haruyama, Junichi
2014-08-01
High-resolution optical images returned from recent lunar missions provide a new chance for estimation of lunar regolith thickness using morphology and the size-frequency distribution of small impact craters. In this study, regolith thickness over the Sinus Iridum region is estimated using Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Cameras (NACs) images. A revised relationship between crater geometry and regolith thickness is proposed based on old experimental data that takes into considering the effect of the illumination angle of the images. In total, 227 high-resolution LROC NAC images are used, and 378,556 impact craters with diameters from 4.2 to 249.8 m are counted, and their morphologies are identified. Our results show that 50% of the Sinus Iridum region has a regolith thickness between 5.1 and 10.7 m, and the mean and median regolith thicknesses are 8.5 and 8.0 m, respectively. There are substantial regional variations in the regolith thickness, with its median value varying from 2.6 to 12.0 m for most regions. Local variations of regolith thickness are found to be correlated with the lunar surface age: the older the surface, the greater the thickness. In addition, sporadically distributed impact ejecta and crater rays are associated with relatively larger regolith thickness, which might result from excavation and transport of materials during the formation of the secondaries of Copernican-aged craters. Our estimated regolith thickness can help with future analysis of Chang'E-3 lunar penetrating radar echoes and studies of the subsurface stratigraphic structure of the Moon.
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100 New Impact Crater Sites Found on Mars
Kennedy, M. R.; Malin, M. C.
2009-12-01
Recent observations constrain the formation of 100 new impact sites on Mars over the past decade; 19 of these were found using the Mars Global Surveyor Mars Orbiter Camera (MOC), and the other 81 have been identified since 2006 using the Mars Reconnaissance Orbiter Context Camera (CTX). Every 6 meter/pixel CTX image is examined upon receipt and, where they overlap images of 0.3-240 m/pixel scale acquired by the same or other Mars-orbiting spacecraft, we look for features that may have changed. New impact sites are initially identified by the presence of a new dark spot or cluster of dark spots in a CTX image. Such spots may be new impact craters, or result from the effect of impact blasts on the dusty surface. In some (generally rare) cases, the crater is sufficiently large to be resolved in the CTX image. In most cases, however, the crater(s) cannot be seen. These are tentatively designated as “candidate” new impact sites, and the CTX team then creates an opportunity for the MRO spacecraft to point its cameras off-nadir and requests that the High Resolution Imaging Science Experiment (HiRISE) team obtain an image of ~0.3 m/pixel to confirm whether a crater or crater cluster is present. It is clear even from cursory examination that the CTX observations are areographically biased to dusty, higher albedo areas on Mars. All but 3 of the 100 new impact sites occur on surfaces with Lambert albedo values in excess of 23.5%. Our initial study of MOC images greatly benefited from the initial global observations made in one month in 1999, creating a baseline date from which we could start counting new craters. The global coverage by MRO Mars Color Imager is more than a factor of 4 poorer in resolution than the MOC Wide Angle camera and does not offer the opportunity for global analysis. Instead, we must rely on partial global coverage and global coverage that has taken years to accumulate; thus we can only treat impact rates statistically. We subdivide the total data
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Dhingra, D.; Head, J. W., III; Pieters, C. M.
2014-12-01
We have completed high resolution geological mapping of impact melt deposits at the young lunar complex craters (wall and rim impact melt units and their relation to floor units have also been mapped. Among the distinctive features of these impact melt deposits are: 1) Impact Melt Wave Fronts: These are extensive (sometimes several kilometers in length) and we have documented their occurrence and distribution in different parts of the crater floor at Jackson and Tycho. These features emphasize melt mobility and style of emplacement during the modification stage of the craters. 2) Variations in Floor Elevations: Spatially extensive and coherent sections of crater floors have different elevations at all the three craters. The observed elevation differences could be caused by subsidence due to cooling of melt and/or structural failure, together with a contribution from regional slope. 3) Melt-Covered Megablocks: We also observe large blocks/rock-fragments (megablocks) covered in impact melt, which could be sections of collapsed wall or in some cases, subdued sections of central peaks. 4) Melt-Covered Central Peaks: Impact melt has also been mapped on the central peaks but varies in spatial extent among the craters. The presence of melt on peaks must be taken into account when interpreting peak mineralogy as exposures of deeper crust. 5) Boulder Distribution: Interesting trends are observed in the distribution of boulder units of various sizes; some impact melt units have spatially extensive boulders, while boulder distribution is very scarce in other units on the floor. We interpret these distributions to be influenced by a) the differential collapse of the crater walls during the modification stage, and b) the amount of relative melt volume retained in different parts of the crater floor. These observations provide important documentation of the morphological diversity and better understanding of the emplacement and final distribution of impact melt deposits.
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Dynamics of crater formations in immersed granular materials
Varas, G.; Vidal, V.; Géminard, J.
2009-12-01
Craters are part of the widespread phenomena observed in nature. Among the main applications to natural phenomena, aside from meteorite impact craters, are the formation and growth of volcanic edifices, by successive ejecta emplacement and/or erosion. The time evolution and dynamics play a crucial role here, as the competition between volcanic-jet mass-flux (degassing and ejecta) and crater-size evolution may control directly the eruptive regime. Crater morphology in dry granular material has been extensively studied, both experimentally and theoretically. Most of these studies investigate the final, steady crater shape resulting from the collision of solid bodies with the material surface and scaling laws are derived. In immersed granular material, craters generated by an underwater vortex ring, or underwater impact craters generated by landslide, have been reported. In a previous experimental study, Gostiaux et al. [Gran. Matt., 2002] have investigated the dynamics of air flowing through an immersed granular layer. They reported that, depending on the flow rate, the system exhibits two qualitatively different regimes: At small flow rate, the bubbling regime during which bubbles escape the granular layer independently one from another; At large flow rate, the open-channel regime which corresponds to the formation of a channel crossing the whole thickness of the granular bed through which air escapes almost continuously. At intermediate flow rate, a spontaneous alternation between these two regimes is observed. Here, we report the dynamics of crater formations at the free surface of an immersed granular bed, locally crossed by an ascending gas flow. We reproduce the experimental conditions of Gostiaux et al. (2002) in two dimensions: In a vertical Hele-Shaw cell, the crater consists of two sand piles which develop around the location of the gas emission. We observe that the typical size of the crater increases logarithmically with time, independently of the gas
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Surface age of venus: use of the terrestrial cratering record
International Nuclear Information System (INIS)
Schaber, G.G.; Shoemaker, E.M.; Kozak, R.C.
1987-01-01
The average crater age of Venus' northern hemisphere may be less than 250 m.y. assuming equivalence between the recent terrestrial cratering rate and that on Venus for craters ≥ 20 km in diameter. For craters larger than this threshold size, below which crater production is significantly affected by the Venusian atmosphere, there are fairly strong observational grounds for concluding that such an equivalence in cratering rates on Venus and Earth may exist. However, given the uncertainties in the role of both active and inactive comet nuclei in the cratering history of Earth, we conclude that the age of the observed surface in the northern hemisphere of Venus could be as great as the 450-m.y. mean age of the Earth's crust. The observed surface of Venus might be even older, but no evidence from the crater observations supports an age as great as 1 b.y. If the age of the observed Venusian surface were 1 b.y., it probably should bear the impact scars of a half dozen or more large comet nuclei that penetrated the atmosphere and formed craters well over 100 km in diameter. Venera 15/16 mapped only about 25% of Venus; the remaining 75% may tell us a completely different story
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Crystal-Chemical Analysis of Soil at Rocknest, Gale Crater
Morrison, S. M.; Downs, R. T.; Blake, D. F.; Bish, D. L.; Ming, D. W.; Morris, R. V.; Yen, A. S.; Chipera, S. J.; Treiman, A. H.; Vaniman, D. T.;
2013-01-01
The CheMin instrument on the Mars Science Laboratory rover Curiosity performed X-ray diffraction analysis on Martian soil [1] at Rocknest in Gale Crater. In particular, crystalline phases from scoop 5 were identified and analyzed with the Rietveld method [2]. Refined unit-cell parameters are reported in Table 1. Comparing these unit-cell parameters with those in the literature provides an estimate of the chemical composition of the crystalline phases. For instance, Fig. 1 shows the Mg-content of Fa-Fo olivine as a function of the b unit-cell parameter using literature data. Our refined b parameter is indicated by the black triangle.
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The First X-ray Diffraction Patterns of Clay Minerals from Gale Crater
Bristow, Thomas; Blake, David; Bish, David L.; Vaniman, David; Ming, Douglas W.; Morris, Richard V.; Chipera, Steve; Rampe, Elizabeth B.; Farmer, Jack, D.; Treiman, Allan H;
2013-01-01
The Mars Science Laboratory (MSL) Rover, Curiosity spent approx 150 sols at Yellowknife Bay (YKB) studying a section of fluvio-lacustrine sedimentary rocks (with potential indications of volcanic influence), informally known as the Yellowknife Bay formation. YKB lies in a distal region of the Peace Vallis alluvial fan, which extends from the northern rim of Gale Crater toward the dune field at the base of Mt Sharp. Sedimentological and stratigraphic observations are consistent with the Yellowknife Bay formation being part of a distal fan deposit, which could be as young as middle Hesperian to even early Amazonian in age (approx 3.5 to 2.5 Ga). The Yellowknife Bay formation hosts a unit of mudstone called the Sheepbed member. Curiosity obtained powdered rock samples from two drill holes in the Sheepbed Member, named John Klein and Cumberland, and delivered them to instruments in Curiosity. Data from CheMin, a combined X-ray diffraction (XRD)/X-ray fluorescence instrument (XRF), has allowed detailed mineralogical analysis of mudstone powders revealing a clay mineral component of approx 20 wt.% in each sample. The clay minerals are important indicators of paleoenvironmental conditions and sensitive recorders of post-depositional alteration processes. The XRD pattern of John Klein reveals a 021 band consistent with a trioctahedral phyllosilicate. A broad peak at approx 10A with a slight inflexion at approx 12A indicates the presence of 2:1 type clay minerals in the John Klein sample. The trioctahedral nature of the clay minerals, breadth of the basal reflection, and presence of a minor component with larger basal spacing suggests that John Klein contains a trioctahedral smectite (probably saponite), whose interlayer is largely collapsed because of the low-humidity conditions. The XRD patterns show no evidence of corrensite (mixed-layer chlorite/smectite) or chlorite, which are typical diagenetic products of trioctahedral smectites when subjected to burial and heating
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Impact spacecraft imagery and comparative morphology of craters
International Nuclear Information System (INIS)
Moutsoulas, M.; Piteri, S.
1979-01-01
The use of hard-landing 'simple' missions for wide-scale planetary exploration is considered. As an example of their imagery potentialities, Ranger VII data are used for the study of the morphological characteristics of 16 Mare Cognitum craters. The morphological patterns of lunar craters, expressed in terms of the Depth/Diameter ratios appear to be in most cases independent of the crater location or size. (Auth.)
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Geomorphology of crater and basin deposits - Emplacement of the Fra Mauro formation
Morrison, R. H.; Oberbeck, V. R.
1975-01-01
Characteristics of continuous deposits near lunar craters larger than about 1 km wide are considered, and it is concluded that (1) concentric dunes, radial ridges, and braided lineations result from deposition of the collision products of ejecta from adjacent pairs of similarly oriented secondary-crater chains and are, therefore, concentrations of secondary-crater ejecta; (2) intracrater ridges are produced within preexisting craters surrounding a fresh primary crater by ricocheting and focusing of secondary-crater ejecta from the preexisting craters' walls; and (3) secondary cratering has produced many of the structures of the continuous deposits of relatively small lunar craters and is the dominant process for emplacement of most of the radial facies of the continuous deposits of large lunar craters and basins. The percentages of Imbrium ejecta in deposits and the nature of Imbrium sculpturing are investigated.
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National Aeronautics and Space Administration, Washington, DC.
The major events of the first manned moon landing mission, Apollo 11, are presented in chronological order from launch time until arrival of the astronauts aboard the U.S.S. Hornet. The log is descriptive, non-technical, and includes numerous color photographs of the astronauts on the moon. (PR)
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Quantitative EPMA of Nano-Phase Iron-Silicides in Apollo 16 Lunar Regolith
Gopon, P.; Fournelle, J.; Valley, J. W.; Pinard, P. T.; Sobol, P.; Horn, W.; Spicuzza, M.; Llovet, X.; Richter, S.
2013-12-01
Until recently, quantitative EPMA of phases under a few microns in size has been extremely difficult. In order to achieve analytical volumes to analyze sub-micron features, accelerating voltages between 5 and 8 keV need to be used. At these voltages the normally used K X-ray transitions (of higher Z elements) are no longer excited, and we must rely of outer shell transitions (L and M). These outer shell transitions are difficult to use for quantitative EPMA because they are strongly affected by different bonding environments, the error associated with their mass attenuation coefficients (MAC), and their proximity to absorption edges. These problems are especially prevalent for the transition metals, because of the unfilled M5 electron shell where the Lα transition originates. Previous studies have tried to overcome these limitations by using standards that almost exactly matched their unknowns. This, however, is cumbersome and requires accurate knowledge of the composition of your sample beforehand, as well as an exorbitant number of well characterized standards. Using a 5 keV electron beam and utilizing non-standard X-ray transitions (Ll) for the transition metals, we are able to conduct accurate quantitative analyses of phases down to ~300nm. The Ll transition in the transition metals behaves more like a core-state transition, and unlike the Lα/β lines, is unaffected by bonding effects and does not lie near an absorption edge. This allows for quantitative analysis using standards do not have to exactly match the unknown. In our case pure metal standards were used for all elements except phosphorus. We present here data on iron-silicides in two Apollo 16 regolith grains. These plagioclase grains (A6-7 and A6-8) were collected between North and South Ray Craters, in the lunar highlands, and thus are associated with one or more large impact events. We report the presence of carbon, nickel, and phosphorus (in order of abundance) in these iron-silicide phases
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A concept of row crater enhancement
International Nuclear Information System (INIS)
Redpath, B.B.
1970-01-01
Linear craters formed by the simultaneous detonation of a row of buried explosives will probably have a wider application than single charges in the explosive excavation of engineering structures. Most cratering experience to date has been with single charges, and an analytical procedure for the design of a row of charges to excavate a crater with a specified configuration has been lacking. There are no digital computer codes having direct application to a row of charges as there are for single charges. This paper derives a simple relationship which can be used to design row charges with some assurance of achieving the desired result and with considerable flexibility in the choice of explosive yield of the individual charges
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Discoveries from Revisiting Apollo Direct Active Measurements of Lunar Dust
O'Brien, Brian
2010-05-01
New missions to the moon being developed by China, Japan, India, USA, Russia and Europe and possibilities of human missions about 2020 face the reality that 6 Apollo expeditions did not totally manage or mitigate effects of easily-mobilised and very "sticky" lunar dust on humans and hardware. Laboratory and theoretical modelling cannot reliably simulate the complex lunar environments that affect dynamical movements of lunar dust. The only direct active measurements of lunar dust during Apollo were made by matchbox-sized minimalist Dust Detector Experiments (DDEs) deployed to transmit some 30 million digital measurements from Apollo 11, 12, 14 and 15. These were misplaced or relatively ignored until 2009, when a self-funded suite of discoveries (O'Brien Geophys. Research Letters FIX 6 May 2099) revealed unexpected properties of lunar dust, such as the adhesive force being stronger as illumination increased. We give the first reports of contrasting effects, contamination or cleansing, from rocket exhausts of Apollo 11, 12, 14 and 15 Lunar Modules leaving the moon. We further strengthen the importance of collateral dust inadvertently splashed on Apollo hardware by human activities. Dust management designs and mission plans require optimum use of such in situ measurements, extended by laboratory simulations and theoretical modelling.
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2003-01-01
[figure removed for brevity, see original site] Released 12 November 2003The rims of two old and degraded impact craters are intersected by a graben in this THEMIS image taken near Mangala Fossa. Yardangs and low-albedo wind streaks are observed at the top of the image as well as interesting small grooves on the crater floor. The origin of these enigmatic grooves may be the result of mud or lava and volatile interactions. Variable surface textures observed in the bottom crater floor are the result of different aged lava flows.Image information: VIS instrument. Latitude -15.2, Longitude 219.2 East (140.8 West). 19 meter/pixel resolution.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
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Vertical view of Apollo 16 landing site located Descartes area lunar nearside
1971-01-01
A vertical view of the Apollo 16 landing site located in the Descartes area lunar nearside. The overlay indicates the location of the proposed touchdown point for the Apollo 16 Lunar Module. Descartes is located west of the Sea of Nectar and southwest of the Sea of Tranquility. This photograph was taken with a 500mm lens camera from lunar orbit by the Apollo 14 crew.
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Tatsumi, Eri; Sugita, Seiji
2018-01-01
scaling law, we found that the crater retention age on Itokawa is 3-33 Myr in the main belt, which is in good agreement with the cosmic-ray-exposure ages for returned samples from Itokawa which may reflect the age of material a few meters beneath the surface. These ages strongly suggest that the global resurfacing that reset the 1-10 m deep surface layer may have occurred in the main belt long after the possible catastrophic disruption of a rigid parent body of Itokawa suggested by Ar degassing age ( ∼ 1.3 Gyr).
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Crater populations in the early history of Mercury
International Nuclear Information System (INIS)
Guest, J.E.; Gault, D.E.
1976-01-01
Crater populations on two major geologic units of Mercury have been classified into three morphologic types which characterize their state of degradation. The results indicate that one or more processes either prior to or contemporary with the formation of the 1300 km diameter Caloris Planitia reduced the population of fresh craters smaller than 70--80 km diameter and totally erased the population of fresh craters smaller than 20--30 km
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Cratering on Small Bodies: Lessons from Eros
Chapman, C. R.
2003-01-01
Cratering and regolith processes on small bodies happen continuously as interplanetary debris rains down on asteroids, comets, and planetary satellites. Butthey are very poorly observed and not well understood. On the one hand, we have laboratory experimentation at small scales and we have examination of large impact craters (e.g. Meteor Crater on Earth and imaging of abundant craters on terrestrial planets and outer planet moons). Understanding cratering on bodies of intermediate scales, tens of meters to hundreds of km in size, involves either extrapolation from our understanding of cratering phenomena at very different scales or reliance on very preliminary, incomplete examination of the observational data we now have for a few small bodies. I review the latter information here. It has been generally understood that the role of gravity is greatly diminished for smaller bodies, so a lot of cratering phenomena studied for larger bodies is less applicable. But it would be a mistake to imagine that laboratory experiments on gravitationless rocks (usually at 1 g) are directly applicable, except perhaps to those monolithic Near Earth Asteroids (NEAs) some tens of meters in size that spin very rapidly and can be assumed to be "large bare rocks" with "negative gravity". Whereas it had once been assumed that asteroids smaller than some tens of km diameter would retain little regolith, it is increasingly apparent that regolith and megoregolith processes extend down to bodies only hundreds of meters in size, perhaps smaller. Yet these processes are very different from those that pertain to the Moon, which is our chief prototype of regolith processes. The NEAR Shoemaker spacecraft's studies of Eros provide the best evidence to date about small-body cratering processes, as well as a warning that our theoretical understanding requires anchoring by direct observations. Eros: "Ponds", Paucity of Small Craters, and Other Mysteries. Although Eros is currently largely detached
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The Impact of Apollo-Era Microbiology on Human Space Flight
Elliott, T. F; Castro, V. A.; Bruce, R. J.; Pierson, D. L.
2014-01-01
The microbiota of crewmembers and the spacecraft environment contributes significant risk to crew health during space flight missions. NASA reduces microbial risk with various mitigation methods that originated during the Apollo Program and continued to evolve through subsequent programs: Skylab, Shuttle, and International Space Station (ISS). A quarantine of the crew and lunar surface samples, within the Lunar Receiving Laboratory following return from the Moon, was used to prevent contamination with unknown extraterrestrial organisms. The quarantine durations for the crew and lunar samples were 21 days and 50 days, respectively. A series of infections among Apollo crewmembers resulted in a quarantine before launch to limit exposure to infectious organisms. This Health Stabilization Program isolated the crew for 21 days before flight and was effective in reducing crew illness. After the program developed water recovery hardware for Apollo spacecraft, the 1967 National Academy of Science Space Science Board recommended the monitoring of potable water. NASA implemented acceptability limits of 10 colony forming units (CFU) per mL and the absence of viable E. coli, anaerobes, yeasts, and molds in three separate 150 mL aliquots. Microbiological investigations of the crew and spacecraft environment were conducted during the Apollo program, including the Apollo-Soyuz Test Project and Skylab. Subsequent space programs implemented microbial screening of the crew for pathogens and acceptability limits on spacecraft surfaces and air. Microbiology risk mitigation methods have evolved since the Apollo program. NASA cancelled the quarantine of the crew after return from the lunar surface, reduced the duration of the Health Stabilization Program; and implemented acceptability limits for spacecraft surfaces and air. While microbial risks were not a main focus of the early Mercury and Gemini programs, the extended duration of Apollo flights resulted in the increased scrutiny of
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Impact cratering on porous targets in the strength regime
Nakamura, Akiko M.
2017-12-01
Cratering on small bodies is crucial for the collision cascade and also contributes to the ejection of dust particles into interplanetary space. A crater cavity forms against the mechanical strength of the surface, gravitational acceleration, or both. The formation of moderately sized craters that are sufficiently larger than the thickness of the regolith on small bodies, in which mechanical strength plays the dominant role rather than gravitational acceleration, is in the strength regime. The formation of microcraters on blocks on the surface is also within the strength regime. On the other hand, the formation of a crater of a size comparable to the thickness of the regolith is affected by both gravitational acceleration and cohesion between regolith particles. In this short review, we compile data from the literature pertaining to impact cratering experiments on porous targets, and summarize the ratio of spall diameter to pit diameter, the depth, diameter, and volume of the crater cavity, and the ratio of depth to diameter. Among targets with various porosities studied in the laboratory to date, based on conventional scaling laws (Holsapple and Schmidt, J. Geophys. Res., 87, 1849-1870, 1982) the cratering efficiency obtained for porous sedimentary rocks (Suzuki et al., J. Geophys. Res. 117, E08012, 2012) is intermediate. A comparison with microcraters formed on a glass target with impact velocities up to 14 km s-1 indicates a different dependence of cratering efficiency and depth-to-diameter ratio on impact velocity.
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Cratering record in the inner solar system: Implications for earth
International Nuclear Information System (INIS)
Barlow, N.G.
1988-01-01
Internal and external processes have reworked the Earth's surface throughout its history. In particular, the effect of meteorite impacts on the early history of the earth is lost due to fluvial, aeolian, volcanic and plate tectonic action. The cratering record on other inner solar system bodies often provides the only clue to the relative cratering rates and intensities that the earth has experienced throughout its history. Of the five major bodies within the inner solar system, Mercury, Mars, and the Moon retain scars of an early episode of high impact rates. The heavily cratered regions on Mercury, Mars, and the Moon show crater size-frequency distribution curves similar in shape and crater density, whereas the lightly cratered plains on the Moon and Mars show distribution curves which, although similar to each other, are statistically different in shape and density from the more heavily cratered units. The similarities among crater size-frequency distribution curves for the Moon, Mercury, and Mars suggest that the entire inner solar system was subjected to the two populations of impacting objects but Earth and Venus have lost their record of heavy bombardment impactors. Thus, based on the cratering record on the Moon, Mercury, and Mars, it can be inferred that the Earth experienced a period of high crater rates and basin formation prior to about 3.8 BY ago. Recent studies have linked mass extinctions to large terrestrial impacts, so life forms were unable to establish themselves until impact rates decreased substantially and terrestrial conditions became more benign. The possible periodicity of mass extinctions has led to the theory of fluctuating impact rates due to comet showers in the post heavy bombardment period. The active erosional environment on the Earth complicates attempts to verify these showers by erasing geological evidence of older impact craters
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Astronaut John Young during final suiting operations for Apollo 10 mission
1969-01-01
A technician attaches hose from test stand to spacesuit of Astronaut John W. Young, Apollo 10 command module pilot, during final suiting operations for the Apollo 10 lunar orbit mission. Another technician makes adjustment behind Young.
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Apollo Spacecraft 012 Command/Service Module being moved to Operations bldg
1967-01-01
Transfer of Apollo Spacecraft 012 Command/Service Module for mating to the Saturn Lunar Module Adapter No. 05 in the Manned Spacecraft Operations bldg. S/C 012 will be flown on the Apollo/Saturn 204 mission.
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Neil Armstrong talks of his experiences at Apollo 11 anniversary banquet
1999-01-01
Neil Armstrong, former Apollo 11 astronaut, and first man to walk on the moon, talks about his experiences for an enthusiastic audience at the Apollo/Saturn V Center, part of the KSC Visitor Complex. The occasion was a banquet celebrating the 30th anniversary of the Apollo 11 launch and moon landing, July 16 and July 20, 1969. Among other guests at the banquet were astronauts Wally Schirra, Edwin 'Buzz' Aldrin and Walt Cunningham. Gene Cernan was the last man to walk on the moon.
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Topography of the Martian Impact Crater Tooting
Mouginis-Mark, P. J.; Garbeil, H.; Boyce, J. M.
2009-01-01
Tooting crater is approx.29 km in diameter, is located at 23.4degN, 207.5degE, and is classified as a multi-layered ejecta crater [1]. Our mapping last year identified several challenges that can now be addressed with HiRISE and CTX images, but specifically the third dimension of units. To address the distribution of ponded sediments, lobate flows, and volatile-bearing units within the crater cavity, we have focused this year on creating digital elevation models (DEMs) for the crater and ejecta blanket from stereo CTX and HiRISE images. These DEMs have a spatial resolution of approx.50 m for CTX data, and 2 m for HiRISE data. Each DEM is referenced to all of the available individual MOLA data points within an image, which number approx.5,000 and 800 respectively for the two data types
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A global catalogue of Ceres impact craters ≥ 1 km and preliminary analysis
Gou, Sheng; Yue, Zongyu; Di, Kaichang; Liu, Zhaoqin
2018-03-01
The orbital data products of Ceres, including global LAMO image mosaic and global HAMO DTM with a resolution of 35 m/pixel and 135 m/pixel respectively, are utilized in this research to create a global catalogue of impact craters with diameter ≥ 1 km, and their morphometric parameters are calculated. Statistics shows: (1) There are 29,219 craters in the catalogue, and the craters have a various morphologies, e.g., polygonal crater, floor fractured crater, complex crater with central peak, etc.; (2) The identifiable smallest crater size is extended to 1 km and the crater numbers have been updated when compared with the crater catalogue (D ≥ 20 km) released by the Dawn Science Team; (3) The d/D ratios for fresh simple craters, obviously degraded simple crater and polygonal simple crater are 0.11 ± 0.04, 0.05 ± 0.04 and 0.14 ± 0.02 respectively. (4) The d/D ratios for non-polygonal complex crater and polygonal complex crater are 0.08 ± 0.04 and 0.09 ± 0.03. The global crater catalogue created in this work can be further applied to many other scientific researches, such as comparing d/D with other bodies, inferring subsurface properties, determining surface age, and estimating average erosion rate.
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Reporters Interview Family of Apollo 11 Astronaut Neil Armstrong
1969-01-01
Newsmen talked with the wife and sons of Apollo 11 astronaut Neil A. Armstrong after the successful launch of Apollo 11 on its trajectory to the moon. The Apollo 11 mission, the first lunar landing mission, launched from the Kennedy Space Center (KSC) in Florida via the Marshall Space Flight Center (MSFC) developed Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. Aboard the space craft were astronauts Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. (Buzz) Aldrin Jr., Lunar Module (LM) pilot. The CM, 'Columbia', piloted by Collins, remained in a parking orbit around the Moon while the LM, 'Eagle'', carrying astronauts Armstrong and Aldrin, landed on the Moon. On July 20, 1969, Armstrong was the first human to ever stand on the lunar surface, followed by Aldrin. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. With the success of Apollo 11, the national objective to land men on the Moon and return them safely to Earth had been accomplished.
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Processing of gamma-ray spectrometric logs
International Nuclear Information System (INIS)
Umiastowski, K.; Dumesnil, P.
1984-10-01
CEA (Commissariat a l'Energie Atomique) has developped a gamma-ray spectrometric tool, containing an analog-to-digital converter. This new tool permits to perform very precise uranium logs (natural gamma-ray spectrometry), neutron activation logs and litho-density logs (gamma-gamma spectrometric logs). Specific processing methods were developped to treate the particular problems of down-hole gamma-ray spectrometry. Extraction of the characteristic gamma-ray peak, even if they are superposed on the background radiation of very high intensity, is possible. This processing methode enables also to obtain geological informations contained in the continuous background of the spectrum. Computer programs are written in high level language for SIRIUS (VICTOR) and APOLLO computers. Exemples of uranium and neutron activation logs treatment are presented [fr
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Giles, Petrone, and Garriott Chat at Apollo 16 Display
1974-01-01
Huntsville's Jack Giles, Alabama State Senator (left), and Dr. Rocco Petrone, Marshall Space Flight Center Director (Middle), speak with Astronaut Owen Garriott who is inside the Apollo 16 Command Module on display at the Alabama Space and Rocket Center in Huntsville, Alabama. The successful Apollo 16 manned lunar landing mission took place April 16, 1972 through April 27, 1972. (Photograph courtesy of Huntsville/Madison County Public Library)
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Regolith irradiation stratigraphy at the Apollo 16 and 17 landing sites
Crozaz, G.
1978-01-01
Additional fossil track measurements in the Apollo 17 deep drill stem, as well as detailed track studies in section 3 of the Apollo 16 deep drill core are reported. Although the upper part of the Apollo 17 core seems to have accreted rapidly, no evidence for a rapid accretion of the lower part, as postulated by some authors, is found. Despite the apparent inhomogeneity of section 60003, its track record is unexpectedly homogeneous; all levels are heavily irradiated and emplacement of big slabs of material is not favored.
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The Lunar Potential Determination Using Apollo-Era Data and Modern Measurements and Models
Collier, Michael R.; Farrell, William M.; Espley, Jared; Webb, Phillip; Stubbs, Timothy J.; Webb, Phillip; Hills, H. Kent; Delory, Greg
2008-01-01
Since the Apollo era the electric potential of the Moon has been a subject of interest and debate. Deployed by three Apollo missions, Apollo 12, Apollo 14 and Apollo 15, the Suprathermal Ion Detector Experiment (SIDE) determined the sunlit lunar surface potential to be about +10 Volts using the energy spectra of lunar ionospheric thermal ions accelerated toward the Moon. More recently, the Lunar Prospector (LP) Electron Reflectometer used electron distributions to infer negative lunar surface potentials, primarily in shadow. We will present initial results from a study to combine lunar surface potential measurements from both SIDE and the LP/Electron Reflectometer to calibrate an advanced model of lunar surface charging which includes effects from the plasma environment, photoemission, secondaries ejected by ion impact onto the lunar surface, and the lunar wake created downstream by the solar wind-lunar interaction.
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Managing the Moon Program: Lessons Learned from Project Apollo
1999-01-01
There have been many detailed historical studies of the process of deciding on and executing the Apollo lunar landing during the 1960s and early 1970s. From the announcement of President John F Kennedy on May 25, 1961, of his decision to land an American on the Moon by the end of the decade, through the first lunar landing on July 20, 1969, on to the last of six successful Moon landings with Apollo 17 in December 1972, NASA carried out Project Apollo with enthusiasm and aplomb. While there have been many studies recounting the history of Apollo, at the time of the 30th anniversary of the first lunar landing by Apollo 11, it seems appropriate to revisit the process of large-scale technological management as it related to the lunar mission. Consequently, the NASA History Office has chosen to publish this monograph containing the recollections of key partcipants in the management process. The collective oral history presented here was recorded in 1989 at the Johnson Space Center's Gilruth Recreation Center in Houston, Texas. It includes the recollections of key participants in Apollo's administration, addressing issues such as communication between field centers, the prioritization of technological goals, and the delegation of responsibility. The following people participated: George E. Muller, Owen W. Morris, Maxime A. Faget, Robert R. Gilruth, Christopher C. Kraft, and Howard W. (Bill) Tindall. The valuable perspectives of these individuals deepen and expand our understanding of this important historical event. This is the 14th in a series of special studies prepared by the NASA History Office. The Monographs in Aerospace History series is designed to provide a wide variety of investigations relative to the history of aeronautics and space. These publications are intended to be tightly focused in terms of subject, relatively short in length, and reproduced in an inexpensive format to allow timely and broad dissemination to researchers in aerospace history.
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Kempter, K.A.; Rowe, G.L.
2000-01-01
The Active Crater at Rincon de la Vieja volcano, Costa Rica, reaches an elevation of 1750 m and contains a warm, hyper-acidic crater lake that probably formed soon after the eruption of the Rio Blanco tephra deposit approximately 3500 years before present. The Active Crater is buttressed by volcanic ridges and older craters on all sides except the north, which dips steeply toward the Caribbean coastal plains. Acidic, above-ambient-temperature streams are found along the Active Crater's north flank at elevations between 800 and 1000 m. A geochemical survey of thermal and non-thermal waters at Rincon de la Vieja was done in 1989 to determine whether hyper-acidic fluids are leaking from the Active Crater through the north flank, affecting the composition of north-flank streams. Results of the water-chemistry survey reveal that three distinct thermal waters are found on the flanks of Rincon de la Vieja volcano: acid chloride-sulfate (ACS), acid sulfate (AS), and neutral chloride (NC) waters. The most extreme ACS water was collected from the crater lake that fills the Active Crater. Chemical analyses of the lake water reveal a hyper-acidic (pH ~ 0) chloride-sulfate brine with elevated concentrations of calcium, magnesium, aluminum, iron, manganese, copper, zinc, fluorine, and boron. The composition of the brine reflects the combined effects of magmatic degassing from a shallow magma body beneath the Active Crater, dissolution of andesitic volcanic rock, and evaporative concentration of dissolved constituents at above-ambient temperatures. Similar cation and anion enrichments are found in the above-ambient-temperature streams draining the north flank of the Active Crater. The pH of north-flank thermal waters range from 3.6 to 4.1 and chloride:sulfate ratios (1.2-1.4) that are a factor of two greater than that of the lake brine (0.60). The waters have an ACS composition that is quite different from the AS and NC thermal waters that occur along the southern flank of Rincon
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Wrinkle Ridges and Young Fresh Crater
2002-01-01
(Released 10 May 2002) The Science Wrinkle ridges are a very common landform on Mars, Mercury, Venus, and the Moon. These ridges are linear to arcuate asymmetric topographic highs commonly found on smooth plains. The origin of wrinkle ridges is not certain and two leading hypotheses have been put forth by scientists over the past 40 years. The volcanic model calls for the extrusion of high viscosity lavas along linear conduits. This thick lava accumulated over these conduits and formed the ridges. The other model is tectonic and advocates that the ridges are formed by compressional faulting and folding. Today's THEMIS image is of the ridged plains of Lunae Planum located between Kasei Valles and Valles Marineris in the northern hemisphere of the planet. Wrinkle ridges are found mostly along the eastern side of the image. The broadest wrinkle ridges in this image are up to 2 km wide. A 3 km diameter young fresh crater is located near the bottom of the image. The crater's ejecta blanket is also clearly seen surrounding the sharp well-defined crater rim. These features are indicative of a very young crater that has not been subjected to erosional processes. The Story The great thing about the solar system is that planets are both alike and different. They're all foreign enough to be mysterious and intriguing, and yet familiar enough to be seen as planetary 'cousins.' By comparing them, we can learn a lot about how planets form and then evolve geologically over time. Crinkled over smooth plains, the long, wavy raised landforms seen here are called 'wrinkle ridges,' and they've been found on Mars, Mercury, Venus, and the Moon - that is, on rocky bodies that are a part of our inner solar system. We know from this observation that planets (and large-enough moons) follow similar processes. What we don't know for sure is HOW these processes work. Scientists have been trying to understand how wrinkle ridges form for 40 years, and they still haven't reached a conclusion. That
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Apollo premeeris lugejate lemmikautoreid
2010-01-01
Raamatupood Apollo kuulutas välja lugejate lemmikraamatud 2010: Mihkel Raua romaan "Sinine on sinu taevas", tõlketeostest Mika Waltari "Sinuhe : egiptlane", aja- ja elulooraamatutest Mart Laari "101 Eesti ajaloo sündmust", lasteraamatutest Andrus Kivirähki "Kaka ja kevad" ning luuleraamatutest Asko Künnapi, Jürgen Rooste ja Karl Martin Sinijärve "Eesti haiku"
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Aboriginal oral traditions of Australian impact craters
Hamacher, Duane W.; Goldsmith, John
2013-11-01
In this paper we explore Aboriginal oral traditions that relate to Australian meteorite craters. Using the literature, first-hand ethnographic records and field trip data, we identify oral traditions and artworks associated with four impact sites: Gosses Bluff, Henbury, Liverpool and Wolfe Creek. Oral traditions describe impact origins for Gosses Bluff, Henbury and Wolfe Creek Craters, and non-impact origins for Liverpool Crater, with Henbury and Wolfe Creek stories having both impact and non-impact origins. Three impact sites that are believed to have been formed during human habitation of Australia -- Dalgaranga, Veevers, and Boxhole -- do not have associated oral traditions that are reported in the literature.
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Stratigraphic architecture of bedrock reference section, Victoria Crater, Meridiani Planum, Mars
Edgar, Lauren A.; Grotzinger, John P.; Hayes, Alex G.; Rubin, David M.; Squyres, Steve W.; Bell, James F.; Herkenhoff, Ken E.
2012-01-01
The Mars Exploration Rover Opportunity has investigated bedrock outcrops exposed in several craters at Meridiani Planum, Mars, in an effort to better understand the role of surface processes in its geologic history. Opportunity has recently completed its observations of Victoria crater, which is 750 m in diameter and exposes cliffs up to ~15 m high. The plains surrounding Victoria crater are ~10 m higher in elevation than those surrounding the previously explored Endurance crater, indicating that the Victoria crater exposes a stratigraphically higher section than does the Endurance crater; however, Victoria strata overlap in elevation with the rocks exposed at the Erebus crater. Victoria crater has a well-developed geomorphic pattern of promontories and embayments that define the crater wall and that reveal thick bedsets (3–7m) of large-scale cross-bedding, interpreted as fossil eolian dunes. Opportunity was able to drive into the crater at Duck Bay, located on the western margin of Victoria crater. Data from the Microscopic Imager and Panoramic Camera reveal details about the structures, textures, and depositional and diagenetic events that influenced the Victoria bedrock. A lithostratigraphic subdivision of bedrock units was enabled by the presence of a light-toned band that lines much of the upper rim of the crater. In ascending order, three stratigraphic units are named Lyell, Smith, and Steno; Smith is the light-toned band. In the Reference Section exposed along the ingress path at Duck Bay, Smith is interpreted to represent a zone of diagenetic recrystallization; however, its upper contact also coincides with a primary erosional surface. Elsewhere in the crater the diagenetic band crosscuts the physical stratigraphy. Correlation with strata present at nearby promontory Cape Verde indicates that there is an erosional surface at the base of the cliff face that corresponds to the erosional contact below Steno. The erosional contact at the base of Cape Verde
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Application of Apollo cosmic radiation dosimetry to lunar colonization studies
International Nuclear Information System (INIS)
English, R.A.; Bailey, J.V.; Brown, R.D.
1972-01-01
The radiation data gathered from the lunar landing missions of Apollo 11 through Apollo 15 are presented. These data have been analyzed to provide dosimetry evaluation of the ambient radiation and radiation from potential solar particle events for the planning of safe, long-term stays of relatively large numbers of individuals upon the moon. (U.S.)
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The Morphology of Craters on Mercury: Results from MESSENGER Flybys
Barnouin, Oliver S.; Zuber, Maria T.; Smith, David E.; Neumann, Gregory A.; Herrick, Robert R.; Chappelow, John E.; Murchie, Scott L.; Prockter, Louise M.
2012-01-01
Topographic data measured from the Mercury Laser Altimeter (MLA) and the Mercury Dual Imaging System (MDIS) aboard the MESSENGER spacecraft were used for investigations of the relationship between depth and diameter for impact craters on Mercury. Results using data from the MESSENGER flybys of the innermost planet indicate that most of the craters measured with MLA are shallower than those previously measured by using Mariner 10 images. MDIS images of these same MLA-measured craters show that they have been modified. The use of shadow measurement techniques, which were found to be accurate relative to the MLA results, indicate that both small bowl-shaped and large complex craters that are fresh possess depth-to-diameter ratios that are in good agreement with those measured from Mariner 10 images. The preliminary data also show that the depths of modified craters are shallower relative to fresh ones, and might provide quantitative estimates of crater in-filling by subsequent volcanic or impact processes. The diameter that defines the transition from simple to complex craters on Mercury based on MESSENGER data is consistent with that reported from Mariner 10 data.
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Spacecraft Conceptual Design Compared to the Apollo Lunar Lander
Young, C.; Bowie, J.; Rust, R.; Lenius, J.; Anderson, M.; Connolly, J.
2011-01-01
Future human exploration of the Moon will require an optimized spacecraft design with each sub-system achieving the required minimum capability and maintaining high reliability. The objective of this study was to trade capability with reliability and minimize mass for the lunar lander spacecraft. The NASA parametric concept for a 3-person vehicle to the lunar surface with a 30% mass margin totaled was considerably heavier than the Apollo 15 Lunar Module "as flown" mass of 16.4 metric tons. The additional mass was attributed to mission requirements and system design choices that were made to meet the realities of modern spaceflight. The parametric tool used to size the current concept, Envision, accounts for primary and secondary mass requirements. For example, adding an astronaut increases the mass requirements for suits, water, food, oxygen, as well as, the increase in volume. The environmental control sub-systems becomes heavier with the increased requirements and more structure was needed to support the additional mass. There was also an increase in propellant usage. For comparison, an "Apollo-like" vehicle was created by removing these additional requirements. Utilizing the Envision parametric mass calculation tool and a quantitative reliability estimation tool designed by Valador Inc., it was determined that with today?s current technology a Lunar Module (LM) with Apollo capability could be built with less mass and similar reliability. The reliability of this new lander was compared to Apollo Lunar Module utilizing the same methodology, adjusting for mission timeline changes as well as component differences. Interestingly, the parametric concept's overall estimated risk for loss of mission (LOM) and loss of crew (LOC) did not significantly improve when compared to Apollo.
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Recovery and Restoration of Apollo Data - An Update
Williams, D. R.; Taylor, P. T.; Hills, H. K.; Nagihara, S.; Nakamura, Y.; Kiefer, W. S.; Guinness, E. A.
2017-12-01
The effort to restore Apollo lunar data, much of which was stored in obsolete formats and on unwieldy media, typically without sufficient documentation, continues to provide new insights into the workings of the Moon. The endeavor, under the auspices of the NASA Space Science Data Coordinated Archive (NSSDCA) Lunar Data Project and Planetary Data System (PDS) Lunar Data Node, and also funded by LASER and PDART proposals, is designed to take the data from the Apollo orbital instruments, astronaut experiments, and long-lived surface stations and convert them into well-documented, digital formats for archive in the NSSDCA and PDS. The data from the ALSEP (Apollo Lunar Surface Experiment Package) surface stations in particular had not been thoroughly examined. Now in standard digital formats with the aid of modern computers and algorithms, they are yielding long-term information on the lunar environment. We will review the data restoration effort in general, concentrating on data sets we have completed and those we are currently working on, which have resulted in advances in our understanding of the Moon. For example, we have restored the archived ALSEP heat flow data from Apollo 15 and 17 that covered the period from deployment to 1 January 1975 and archived them with PDS. In addition, raw data for a three month period from April to June, 1975 have been discovered and restored, and data from March 1976 through September 1977 have been read from the Apollo Work Tapes. These data confirm the subsurface temperatures at the heat flow site have been warming over many years, even at depth, and have implications for the interpretation of the heat flow coming from the Moon. Examination of the restored Lunar Ejecta And Meteorite (LEAM) data and comparison with the restored ALSEP Housekeeping data indicates that the anomalous signals recorded by LEAM are not due to electrical interference and may be due to charged dust particles. Re-examination of restored Lunar Atmospheric
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Morphological indicators of a mascon beneath Ceres' largest crater, Kerwan
Bland, Michael T.; Ermakov, Anton; Raymond, Carol A.; Williams, David A.; Bowling, Tim J.; Preusker, F.; Park, Ryan S.; Marchi, Simone; Castillo-Rogez, Julie C.; Fu, R.R.; Russell, Christopher T.
2018-01-01
Gravity data of Ceres returned by the National Aeronautics and Space Administration's Dawn spacecraft is consistent with a lower density crust of variable thickness overlying a higher density mantle. Crustal thickness variations can affect the long‐term, postimpact modification of impact craters on Ceres. Here we show that the unusual morphology of the 280 km diameter crater Kerwan may result from viscous relaxation in an outer layer that thins substantially beneath the crater floor. We propose that such a structure is consistent with either impact‐induced uplift of the high‐density mantle beneath the crater or from volatile loss during the impact event. In either case, the subsurface structure inferred from the crater morphology is superisostatic, and the mass excess would result in a positive Bouguer anomaly beneath the crater, consistent with the highest‐degree gravity data from Dawn. Ceres joins the Moon, Mars, and Mercury in having basin‐associated gravity anomalies, although their origin may differ substantially.
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Morphological Indicators of a Mascon Beneath Ceres's Largest Crater, Kerwan
Bland, M. T.; Ermakov, A. I.; Raymond, C. A.; Williams, D. A.; Bowling, T. J.; Preusker, F.; Park, R. S.; Marchi, S.; Castillo-Rogez, J. C.; Fu, R. R.; Russell, C. T.
2018-02-01
Gravity data of Ceres returned by the National Aeronautics and Space Administration's Dawn spacecraft is consistent with a lower density crust of variable thickness overlying a higher density mantle. Crustal thickness variations can affect the long-term, postimpact modification of impact craters on Ceres. Here we show that the unusual morphology of the 280 km diameter crater Kerwan may result from viscous relaxation in an outer layer that thins substantially beneath the crater floor. We propose that such a structure is consistent with either impact-induced uplift of the high-density mantle beneath the crater or from volatile loss during the impact event. In either case, the subsurface structure inferred from the crater morphology is superisostatic, and the mass excess would result in a positive Bouguer anomaly beneath the crater, consistent with the highest-degree gravity data from Dawn. Ceres joins the Moon, Mars, and Mercury in having basin-associated gravity anomalies, although their origin may differ substantially.
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Unusual Microtopography on an Apollo 12 Soil Grain
Thomas-Keprta, K. L.; Keprta, N. T.; Clemett, S. J.; Berger, E. L.; Rahman, Z.; McKay, D. S.; Gibson, E. K.; Wentworth, S. J.
2014-01-01
We have observed the presence of a previously undescribed microtopography in several regions on the surface of a lunar grain from Apollo regolith sample 12070,29. This microtopography consists of flattened triangular prisms, henceforth referred to as denticles, set in an orderly arrangement. We propose three possible processes to describe the presence of these structures: (1) radiation; (2) aqueous activity; or (3) impact. Radiation—the surface of the Earth’s moon is subject to energetic ion and photon irradiation which can produce a multitude of morphological effects on grain surfaces including erosion/sputtering, vesicle formation, and amorphization of crystalline phases. Under certain conditions surface erosion can result in the formation of well-ordered nanostructures including mounds, dots, wave-shaped, rippled or corrugated features typically <10s nm in size and organized into pattered arrays. However larger pyramid-shaped features up to approx. 300 nm at the base, similar in shape to lunar denticles, were produced on Cu substrates ex-posed to ion beam sputtering.. Aqueous alteration—recent reports of purported water on the Moon imply the possibility of brief, limited exposure of surface materials to aqueous fluids. Aqueous corrosion of silicates can result in the formation of crystallographically controlled denticulated features, up to 10s of micron at the base, arranged in a patterned formation. Impact—the surface of the moon is impacted by meteorites, particularly by micron-size particles, resulting in the formation of a variety of crater types. While it is difficult to envision a scenario in which a patterned array could be formed by impact, fracturing along planes of crystallographic structural weakness due to external stress could explain these features.
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ArcGIS Digitization of Apollo Surface Traverses
Petro, N. E.; Bleacher, J. E.; Gladdis, L. R.; Garry, W. B.; Lam, F.; Mest, S. C.
2012-01-01
The Apollo surface activities were documented in extraordinary detail, with every action performed by the astronauts while on the surface recorded either in photo, audio, film, or by written testimony [1]. The samples and in situ measurements the astronauts collected while on the lunar surface have shaped our understanding of the geologic history of the Moon, and the earliest history and evolution of the inner Solar System. As part of an ongoing LASERfunded effort, we are digitizing and georeferencing data from astronaut traverses and spatially associating them to available, co-registered remote sensing data. Here we introduce the products produced so far for Apollo 15, 16, and 17 missions.
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Apollo 11 Astronauts In Prayer Within Quarantine Facility
1969-01-01
The Apollo 11 mission, the first manned lunar mission, launched from the Kennedy Space Center, Florida via a Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. The Saturn V vehicle was developed by the Marshall Space Flight Center (MSFC) under the direction of Dr. Wernher von Braun. Aboard were Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. Aldrin Jr., Lunar Module (LM) pilot. The CM, piloted by Michael Collins remained in a parking orbit around the Moon while the LM, named 'Eagle'', carrying astronauts Neil Armstrong and Edwin Aldrin, landed on the Moon. Armstrong was the first human to ever stand on the lunar surface, followed by Edwin (Buzz) Aldrin. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. The recovery operation took place in the Pacific Ocean where Navy para-rescue men recovered the capsule housing the 3-man Apollo 11 crew. The crew was taken to safety aboard the USS Hornet, where they were quartered in a mobile quarantine facility. Shown here is the Apollo 11 crew inside the quarantine facility as prayer is offered by Lt. Commander John Pirrto, USS Hornet Chaplain accompanied by U.S. President Richard Nixon (front right). With the success of Apollo 11, the national objective to land men on the Moon and return them safely to Earth had been accomplished.
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Summary of results of cratering experiments
International Nuclear Information System (INIS)
Toman, J.
1969-01-01
The use of nuclear excavation as a construction technique for producing harbors, canals, highway cuts, and other large excavations requires a high assurance that the yield and depth of burst selected for the explosive will produce the desired configuration within an acceptable degree of tolerance. Nuclear excavation technology advanced significantly during 1968 as a result of the successful execution of Projects Cabriolet, Buggy, and Schooner. Until these experiments were conducted, the only nuclear data available for designing large excavations were derived from Sedan (100 kt in alluvium), Danny Boy (0.42 kt in basalt), and Sulky (0.090 kt in basalt). Applicable experience has now been extended to include two additional rock types: tuff and porphyritic trachyte, non-homogeneous formations with severe geologic layering, and a nuclear row in hard rock. The continued development of cratering calculations using in situ geophysical measurements and high-pressure test data have provided a means for predicting the cratering characteristics of untested materials. Chemical explosive cratering experiments conducted in the pre-Gondola series during the past several years have been directed toward determining the behavior of weak, wet clay shales. This material is important to nuclear excavation because of potential long-term stability problems which may affect the cratered slopes. (author)
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Summary of results of cratering experiments
Energy Technology Data Exchange (ETDEWEB)
Toman, J [Lawrence Radiation Laboratory, Livermore, CA (United States)
1969-07-01
The use of nuclear excavation as a construction technique for producing harbors, canals, highway cuts, and other large excavations requires a high assurance that the yield and depth of burst selected for the explosive will produce the desired configuration within an acceptable degree of tolerance. Nuclear excavation technology advanced significantly during 1968 as a result of the successful execution of Projects Cabriolet, Buggy, and Schooner. Until these experiments were conducted, the only nuclear data available for designing large excavations were derived from Sedan (100 kt in alluvium), Danny Boy (0.42 kt in basalt), and Sulky (0.090 kt in basalt). Applicable experience has now been extended to include two additional rock types: tuff and porphyritic trachyte, non-homogeneous formations with severe geologic layering, and a nuclear row in hard rock. The continued development of cratering calculations using in situ geophysical measurements and high-pressure test data have provided a means for predicting the cratering characteristics of untested materials. Chemical explosive cratering experiments conducted in the pre-Gondola series during the past several years have been directed toward determining the behavior of weak, wet clay shales. This material is important to nuclear excavation because of potential long-term stability problems which may affect the cratered slopes. (author)
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Goat paddock cryptoexplosion crater, Western Australia
Harms, J.E.; Milton, D.J.; Ferguson, J.; Gilbert, D.J.; Harris, W.K.; Goleby, B.
1980-01-01
Goat Paddock, a crater slightly over 5 km in diameter (18??20??? S, 126??40???E), lies at the north edge of the King Leopold Range/Mueller Range junction in the Kimberley district, Western Australia (Fig. 1). It was noted as a geological anomaly in 1964 during regional mapping by the Bureau of Mineral Resources, Geology and Geophysics and the Geological Survey of Western Australia. The possibility of its being a meteorite impact crater has been discussed1, although this suggestion was subsequently ignored2. Two holes were drilled by a mining corporation in 1972 to test whether kimberlite underlay the structure. Here we report the findings of five days of reconnaissance in August 1979 which established that Goat Paddock is a cryptoexplosion crater containing shocked rocks and an unusually well exposed set of structural features. ?? 1980 Nature Publishing Group.
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Rock spatial densities on the rims of the Tycho secondary craters in Mare Nectaris
Basilevsky, A. T.; Michael, G. G.; Kozlova, N. A.
2018-04-01
The aim of this work is to check whether the technique of estimation of age of small lunar craters based on spatial density of rock boulders on their rims described in Basilevsky et al. (2013, 2015b) and Li et al. (2017) for the craters rock counts on the rims of four craters having diameters 1000, 1100, 1240 and 1400 m located in Mare Nectaris. These craters are secondaries of the primary crater Tycho, whose age was found to be 109 ± 4 Ma (Stoffler and Ryder, 2001) so this may be taken as the age of the four craters, too. Using the dependence of the rock spatial densities at the crater rims on the crater age for the case of mare craters (Li et al., 2017) our measured rock densities correspond to ages from ∼100 to 130 Ma. These estimates are reasonably close to the given age of the primary crater Tycho. This, in turn, suggests that this technique of crater age estimation is applicable to craters up to ∼1.5 km in diameter. For the four considered craters we also measured their depth/diameter ratios and the maximum angles of the crater inner slopes. For the considered craters it was found that with increasing crater diameter, the depth/diameter ratios and maximum angles of internal slopes increase, but the values of these parameters for specific craters may deviate significantly from the general trends. The deviations probably result from some dissimilarities in the primary crater geometries, that may be due to crater to crater differences in characteristics of impactors (e.g., in their bulk densities) and/or differences in the mechanical properties of the target. It may be possible to find secondaries of crater Tycho in the South pole area and, if so, they may be studied to check the specifics and rates of the rock boulder degradation in the lunar polar environment.
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Some Studies of Terrestrial Impact Cratering Rate
Directory of Open Access Journals (Sweden)
Jetsu L.
2011-06-01
Full Text Available In 1984, a 28.4 Myr periodicity was detected in the ages of terrestrial impact craters and a 26 Myr periodicity in the epochs of mass extinctions of species. Periodic comet showers from the Oort cloud seemed to cause catastrophic events linked to mass extinctions of species. Our first study revealed that the only significant detected periodicity is the “human signal” caused by the rounding of these data into integer numbers. The second study confirmed that the original 28.4 Myr periodicity detection was not significant. The third study revealed that the quality and the quantity of the currently available data would allow detection of real periodicity only if all impacts have been periodic, which cannot be the case. The detection of a periodic signal, if present, requires that more craters should be discovered and the accuracy of age estimates improved. If we sometimes will be able to find the difference between the craters caused by asteroid and comet impacts, the aperiodic component could be removed. The lunar impact craters may eventually provide the required supplementary data.
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Apollo 16 Lunar Module 'Orion' at the Descartes landing site
1972-01-01
The Apollo 16 Lunar Module 'Orion' is part of the lunar scene at the Descartes landing site, as seen in the reproduction taken from a color television transmission made by the color TV camera mounted on the Lunar Roving Vehicle. Note the U.S. flag deployed on the left. This picture was made during the second Apollo 16 extravehicular activity (EVA-2).
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Floor-fractured craters on Ceres and implications for interior processes
Buczkowski, Debra; Schenk, Paul M.; Scully, Jennifer E. C.; Park, Ryan; Preusker, Frank; Raymond, Carol; Russell, Christopher T.
2016-10-01
Several of the impact craters on Ceres have patterns of fractures on their floors. These fractures appear similar to those found within a class of lunar craters referred to as Floor-Fractured Craters (FFCs) [Schultz, 1976].Lunar FFCs are characterized by anomalously shallow floors cut by radial, concentric, and/or polygonal fractures, and have been classified into crater classes, Types 1 through 6, based on their morphometric properties [Schultz, 1976; Jozwiak et al, 2012, 2015]. Models for their formation have included both floor uplift due to magmatic intrusion below the crater or floor shallowing due to viscous relaxation. However, the observation that the depth versus diameter (d/D) relationship of the FFCs is distinctly shallower than the same association for other lunar craters supports the hypotheses that the floor fractures form due to shallow magmatic intrusion under the crater [Jozwiak et al, 2012, 2015].FFCs have also been identified on Mars [Bamberg et al., 2014]. Martian FFCs exhibit morphological characteristics similar to the lunar FFCs, and analyses suggest that the Martian FCCs also formed due to volcanic activity, although heavily influenced by interactions with groundwater and/or ice.We have cataloged the Ceres FFCs according to the classification scheme designed for the Moon. Large (>50 km) Ceres FFCs are most consistent with Type 1 lunar FFCs, having deep floors, central peaks, wall terraces, and radial and/or concentric fractures. Smaller craters on Ceres are more consistent with Type 4 lunar FFCs, having less-pronounced floor fractures and a v-shaped moats separating the wall scarp from the crater interior.An analysis of the d/D ratio for Ceres craters shows that, like lunar FFCs, the Ceres FFCs are anomalously shallow. This suggests that the fractures on the floor of Ceres FFCs may be due the intrusion of a low-density material below the craters that is uplifting their floors. While on the Moon and Mars the intrusive material is hypothesized
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Virtual Microscope Views of the Apollo 11, 12, and 15 Lunar Samples
Gibson, E. K.; Tindle, A. G.; Kelley, S. P.; Pillinger, J. M.
2017-01-01
The Apollo virtual microscope is a means of viewing, over the Internet, polished thin sections of every rock in the Apollo lunar sample collections. It uses software that duplicates many of the functions of a petrological microscope.
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Matsumoto, Toru; Hasegawa, S.; Nakao, S.; Sakai, M.; Yurimoto, H.
2018-03-01
We investigated impact crater structures on regolith particles from asteroid Itokawa using scanning electron microscopy. We observed the surfaces of 51 Itokawa particles, ranging from 15 μm to 240 μm in size. Craters with average diameters ranging from 10 nm to 2.8 μm were identified on 13 Itokawa particles larger than 80 μm. We examined the abundance, spatial distribution, and morphology of approximately 900 craters on six Itokawa particles. Craters with sizes in excess of 200 nm are widely dispersed, with spatial densities from 2.6 μm2 to 4.5 μm2; a fraction of the craters was locally concentrated with a density of 0.1 μm2. The fractal dimension of the cumulative crater diameters ranges from 1.3 to 2.3. Craters of several tens of nanometers in diameter exhibit pit and surrounding rim structures. Craters of more than 100 nm in diameter commonly have melted residue at their bottom. These morphologies are similar to those of submicrometer-sized craters on lunar regolith. We estimated the impactor flux on Itokawa regolith-forming craters, assuming that the craters were accumulated during direct exposure to the space environment for 102 to 104 yr. The range of impactor flux onto Itokawa particles is estimated to be at least one order of magnitude higher than the interplanetary dust flux and comparable to the secondary impact flux on the Moon. This indicates that secondary ejecta impacts are probably the dominant cratering process in the submicrometer range on Itokawa regolith particles, as well as on the lunar surface. We demonstrate that secondary submicrometer craters can be produced anywhere in centimeter- to meter-sized depressions on Itokawa's surface through primary interplanetary dust impacts. If the surface unevenness on centimeter to meter scales is a significant factor determining the abundance of submicrometer secondary cratering, the secondary impact flux could be independent of the overall shapes or sizes of celestial bodies, and the secondary
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Restoration and Reexamination of Apollo Lunar Dust Detector Data from Original Telemetry Files
McBride, M. J.; Williams, David R.; Hills, H. Kent
2012-01-01
We are recovering the original telemetry (Figure I) from the Apollo Dust, Thermal, Radiation Environment Monitor (DTREM) experiment, more commonly known as the Dust Detector, and producing full time resolution (54 second) data sets for release through the Planetary Data System (PDS). The primary objective of the experiment was to evaluate the effect of dust deposition, temperature, and radiation damage on solar cells on the lunar surface. The monitor was a small box consisting of three solar cells and thermistors mounted on the ALSEP (Apollo Lunar Surface Experiments Package) central station. The Dust Detector was carried on Apollo's 11, 12, 14 and 15. The Apollo 11 DTREM was powered by solar cells and only operated for a few months as planned. The Apollo 12, 14, and 15 detectors operated for 5 to 7 years, returning data every 54 seconds, consisting of voltage outputs from the three solar cells and temperatures measured by the three thermistors. The telemetry was received at ground stations and held on the Apollo Housekeeping (known as "Word 33") tapes. made available to the National Space Science Data Center (NSSDC) by Yosio Nakamura (University of Texas Institute for Geophysics). We have converted selected parts of the telemetry into uncalibrated and calibrated output voltages and temperatures.
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Are pre-crater mounds gas-inflated?
Leibman, Marina; Kizyakov, Alexandr; Khomutov, Artem; Dvornikov, Yury; Babkina, Elena; Arefiev, Stanislav; Khairullin, Rustam
2017-04-01
Gas-emission craters (GEC) on Yamal peninsula, which occupied minds of researches for the last couple of years since first discovered in 2014, appeared to form on the place of specifically shaped mounds. There was a number of hypotheses involving pingo as an origin of these mounds. This arouse an interest in mapping pingo thus marking the areas of GEC formation risk. Our field research allows us to suggest that remote-sensing-based mapping of pingo may result in mix up of mounds of various origin. Thus, we started with classification of the mounds based on remote-sensing, field observations and survey from helicopter. Then we compared indicators of mounds of various classes to the properties of pre-crater mounds to conclude on their origin. Summarizing field experience, there are three main mound types on Yamal. (1) Outliers (remnant hills), separated from the main geomorphic landform by erosion. Often these mounds comprise polygonal blocks, kind of "baydzherakh". Their indicators are asymmetry (short gentle slope towards the main landform, and steep slope often descending into a small pond of thermokarst-nivation origin), often quadrangle or conic shape, and large size. (2) Pingo, appear within the khasyrei (drain lake basin); often are characterized by open cracks resulting from expansion of polygonal network formed when re-freezing of lake talik prior to pingo formation; old pingo may bear traces of collapse on the top, with depression which differs from the GEC by absence of parapet. (3) Frost-heave mounds (excluding pingo) may form on deep active layer, reducing due to moss-peat formation and forming ice lenses from an active layer water, usually they appear in the drainage hollows, valley bottoms, drain-lake basins periphery. These features are smaller than the first two types of mounds. Their tops as a rule are well vegetated. We were unable to find a single or a set of indicators unequivocally defining any specific mound type, thus indicators of pre-crater
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Study of melt produced bodies observed at Henbury crater region
International Nuclear Information System (INIS)
Hopper, V.D.; Sewell, D.K.B.; Aitken, D.K.
1989-01-01
Spherical and non spherical bodies derived from target rock and meteorite components have been found in samples of soil in the Henbury crater region. From a study of the composition of these bodies, the compositions of the meteorite and the target rock, it has been possible to separate the bodies into three groups showing differing degrees of volatilization of various oxides. The composition of a number of the soil samples were measured using X-ray fluorescence. A selected number were then examined by a scanning electron microscope fitted with an energy dispersive X-ray analyzer. Where Ni was definitely identified, it was examined by an electron microprobe X-ray analyzer. A major finding was the depletion of SiO 2 in the production of both Group 1 and Group 3 bodies. Group 3 bodies are not volatilized to the same extent as Group 1. With no reference to the target rock , the general order of volatility appears to be Na 2 O>MgO>K 2 O>TiO 2 , SiO 2 and Al 2 O 3 , the significant change being the place of SiO2. 13 refs., 7 figs., 5 tabs
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NASA Officials in MCC to decide whether to land Apollo 16 or cancel landing
1972-01-01
NASA Officials gather around a console in the Mission Operations Control Room (MOCR) in the Mission Control Center (MCC) prior to the making of a decision whether to land Apollo 16 on the moon or to abort the landing. Seated, left to right, are Dr. Christopher C. Kraft Jr., Director of the Manned Spacecraft Center (MSC), and Brig. Gen. James A. McDivitt (USAF), Manager, Apollo Spacecraft Program Office, MSC; and standing, left to right, are Dr. Rocco A. Petrone, Apollo Program Director, Office Manned Space Flight (OMSF), NASA HQ.; Capt. John K. Holcolmb (U.S. Navy, Ret.), Director of Apollo Operations, OMSF; Sigurd A. Sjoberg, Deputy Director, MSC; Capt. Chester M. Lee (U.S. Navy, Ret.), Apollo Mission Director, OMSF; Dale D. Myers, NASA Associate Administrator for Manned Space Flight; and Dr. George M. Low, NASA Deputy Administrator.
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Rathbun, K.; Ukstins, I.; Drop, S.
2017-12-01
Monturaqui Crater is a small ( 350 m diameter), simple meteorite impact crater located in the Atacama Desert of northern Chile that was emplaced in Ordovician granite overlain by discontinuous Pliocene ignimbrite. Ejecta deposits are granite and ignimbrite, with lesser amounts of dark impact melt and rare tektites and iron shale. The impact restructured existing drainage systems in the area that have subsequently eroded through the ejecta. Satellite-based mapping and modeling, including a synthesis of photographic satellite imagery and ASTER thermal infrared imagery in ArcGIS, were used to construct a basic geological interpretation of the site with special emphasis on understanding ejecta distribution patterns. This was combined with field-based mapping to construct a high-resolution geologic map of the crater and its ejecta blanket and field check the satellite-based geologic interpretation. The satellite- and modeling-based interpretation suggests a well-preserved crater with an intact, heterogeneous ejecta blanket that has been subjected to moderate erosion. In contrast, field mapping shows that the crater has a heavily-eroded rim and ejecta blanket, and the ejecta is more heterogeneous than previously thought. In addition, the erosion rate at Monturaqui is much higher than erosion rates reported elsewhere in the Atacama Desert. The bulk compositions of the target rocks at Monturaqui are similar and the ejecta deposits are highly heterogeneous, so distinguishing between them with remote sensing is less effective than with direct field observations. In particular, the resolution of available imagery for the site is too low to resolve critical details that are readily apparent in the field on the scale of 10s of cm, and which significantly alter the geologic interpretation. The limiting factors for effective remote interpretation at Monturaqui are its target composition and crater size relative to the resolution of the remote sensing methods employed. This
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Acoustic fluidization and the scale dependence of impact crater morphology
Melosh, H. J.; Gaffney, E. S.
1983-01-01
A phenomenological Bingham plastic model has previously been shown to provide an adequate description of the collapse of impact craters. This paper demonstrates that the Bingham parameters may be derived from a model in which acoustic energy generated during excavation fluidizes the rock debris surrounding the crater. Experimental support for the theoretical flow law is presented. Although the Bingham yield stress cannot be computed without detailed knowledge of the initial acoustic field, the Bingham viscosity is derived from a simple argument which shows that it increases as the 3/2 power of crater diameter, consistent with observation. Crater collapse may occur in material with internal dissipation Q as low as 100, comparable to laboratory observations of dissipation in granular materials. Crater collapse thus does not require that the acoustic field be regenerated during flow.
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Heavy Cratering near Callisto's South Pole
1997-01-01
Images from NASA's Galileo spacecraft provide new insights into this region near Callisto's south pole. This two frame mosaic shows a heavily cratered surface with smooth plains in the areas between craters. North is to the top of the image. The smoothness of the plains appears to increase toward the south pole, approximately 480 kilometers (293 miles) south of the bottom of the image. This smoothness of Callisto's surface was not evident in images taken during the 1979 flyby of NASA's Voyager spacecraft because the resolution was insufficient to show the effect. This smooth surface, and the process(es) that cause it, are among the most intriguing aspects of Callisto. Although not fully understood, the process(es) responsible for this smoothing could include erosion by tiny meteorites and energetic ions. Some craters, such as Keelut, the 47 kilometer (29 mile) crater in the lower right corner, have sharp, well defined rims. Keelut contains an inner ring surrounding a central depression about 17 kilometers (11 miles) in diameter. Keelut, and the more irregularly shaped, degraded Reginleif, the 32 kilometer (19.5 mile) crater in the top center of the image, are very shallow and have flat floors. Crater forms can be seen down to less than 2 kilometers (1.2 miles) in diameter in the image. Each picture element (pixel) in this image is approximately 0.68 kilometers (0.41 miles) across.This image which was taken by the Galileo spacecraft's solid state imaging (CCD) system during its eighth orbit around Jupiter, on May 6th, 1997. The center of the image is located at 71.3 degrees south latitude, 97.6 degrees west longitude, and was taken when the spacecraft was approximately 35,470 kilometers (21,637 miles) from Callisto.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http
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Artist's concept of eastward view of Apollo 16 Descartes landing site
1972-01-01
An artist's concept illustrating an eastward view of the Apollo 16 Descartes landing site. The white overlay indicates the scheduled tranverses by the Apollo 16 astronauts in the Lunar Roving Vehicle. The Roman numerals are the extravehicular activities (EVA's); and the Arabic numbers are the station stops along the traverse.
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Crater relaxation on Titan aided by low thermal conductivity sand infill
Schurmeier, Lauren R.; Dombard, Andrew J.
2018-05-01
Titan's few impact craters are currently many hundreds of meters shallower than the depths expected. Assuming these craters initially had depths equal to that of similar-size fresh craters on Ganymede and Callisto (moons of similar size, composition, and target lithology), then some process has shallowed them over time. Since nearly all of Titan's recognized craters are located within the arid equatorial sand seas of organic-rich dunes, where rain is infrequent, and atmospheric sedimentation is expected to be low, it has been suggested that aeolian infill plays a major role in shallowing the craters. Topographic relaxation at Titan's current heat flow was previously assumed to be an unimportant process on Titan due to its low surface temperature (94 K). However, our estimate of the thermal conductivity of Titan's organic-rich sand is remarkably low (0.025 W m-1 K-1), and when in thick deposits, will result in a thermal blanketing effect that can aid relaxation. Here, we simulate the relaxation of Titan's craters Afekan, Soi, and Sinlap including thermal effects of various amounts of sand inside and around Titan's craters. We find that the combination of aeolian infill and subsequent relaxation can produce the current crater depths in a geologically reasonable period of time using Titan's current heat flow. Instead of needing to fill completely the missing volume with 100% sand, only ∼62%, ∼71%, and ∼97%, of the volume need be sand at the current basal heat flux for Afekan, Soi, and Sinlap, respectively. We conclude that both processes are likely at work shallowing these craters, and this finding contributes to why Titan overall lacks impact craters in the arid equatorial regions.
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Experimental investigation of crater growth dynamics
Schmidt, R. M.; Housen, K. R.; Bjorkman, M. D.; Holsapple, K. A.
1985-01-01
This work is a continuation of an ongoing program whose objective is to perform experiments and to develop scaling relationships for large-body impacts onto planetary surfaces. The centrifuge technique is used to provide experimental data for actual target materials of interest. With both power and gas guns mounted on the rotor arm, it is possible to match various dimensionless similarity parameters, which have been shown to govern the behavior of large-scale impacts. The development of the centrifuge technique has been poineered by the present investigators and is documented by numerous publications, the most recent of which are listed below. Understanding the dependence of crater size upon gravity has been shown to be key to the complete determination of the dynamic and kinematic behavior of crater formation as well as ejecta phenomena. Three unique time regimes in the formation of an impact crater have been identified.
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Comparison between KARBUS and APOLLO 1
International Nuclear Information System (INIS)
Payer, L.; Broeders, C.
1995-01-01
A comparison is made between benchmark calculations by the French APOLLO 1 code and the Karlsruhe KARBUS procedure. Independently these two codes had been developed for transport computations in infinite reactor configurations and for burnup calculations. (orig.)
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2002-01-01
The Barringer Meteorite Crater (also known as 'Meteor Crater') is a gigantic hole in the middle of the arid sandstone of the Arizona desert. A rim of smashed and jumbled boulders, some of them the size of small houses, rises 50 m above the level of the surrounding plain. The crater itself is nearly a 1500 m wide, and 180 m deep. When Europeans first discovered the crater, the plain around it was covered with chunks of meteoritic iron - over 30 tons of it, scattered over an area 12 to 15 km in diameter. Scientists now believe that the crater was created approximately 50,000 years ago. The meteorite which made it was composed almost entirely of nickel-iron, suggesting that it may have originated in the interior of a small planet. It was 50 m across, weighed roughly 300,000 tons, and was traveling at a speed of 65,000 km per hour. This ASTER 3-D perspective view was created by draping an ASTER bands 3-2-1image over a digital elevation model from the US Geological Survey National Elevation Dataset.This image was acquired on May 17, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along
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Measuring impact crater depth throughout the solar system
Robbins, Stuart J.; Watters, Wesley A.; Chappelow, John E.; Bray, Veronica J.; Daubar, Ingrid J.; Craddock, Robert A.; Beyer, Ross A.; Landis, Margaret E.; Ostrach, Lillian; Tornabene, Livio L.; Riggs, Jamie D.; Weaver, Brian P.
2018-01-01
One important, almost ubiquitous, tool for understanding the surfaces of solid bodies throughout the solar system is the study of impact craters. While measuring a distribution of crater diameters and locations is an important tool for a wide variety of studies, so too is measuring a crater's “depth.” Depth can inform numerous studies including the strength of a surface and modification rates in the local environment. There is, however, no standard data set, definition, or technique to perform this data‐gathering task, and the abundance of different definitions of “depth” and methods for estimating that quantity can lead to misunderstandings in and of the literature. In this review, we describe a wide variety of data sets and methods to analyze those data sets that have been, are currently, or could be used to derive different types of crater depth measurements. We also recommend certain nomenclature in doing so to help standardize practice in the field. We present a review section of all crater depths that have been published on different solar system bodies which shows how the field has evolved through time and how some common assumptions might not be wholly accurate. We conclude with several recommendations for researchers which could help different data sets to be more easily understood and compared.
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Conversion of CATHENA from the VAX to APOLLO computer
International Nuclear Information System (INIS)
Kawa, D.M.
1986-12-01
The thermal-hydraulic computer code developed by Atomic Energy of Canada Limited, CATHENA, has been converted from the VAX computer to operate on a low-cost, high-performance APOLLO 3000 work station. Full functionality of the program has been retained. Three verification cases have been analyzed which indicate accuracy to the sixth decimal place as printed in output listings. The APOLLO 3000 computing times for the 3 cases are approximately 15% faster than achieved on the Wardrop VAX 11 750
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76 FR 7853 - Patient Safety Organizations: Voluntary Delisting From Apollo Publishing, Inc.
2011-02-11
... notification of voluntary relinquishment from Apollo Publishing, Inc., of its status as a Patient Safety... DEPARTMENT OF HEALTH AND HUMAN SERVICES Agency for Healthcare Research and Quality Patient Safety Organizations: Voluntary Delisting From Apollo Publishing, Inc. AGENCY: Agency for Healthcare Research and...
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Noachian and more recent phyllosilicates in impact craters on Mars.
Fairén, Alberto G; Chevrier, Vincent; Abramov, Oleg; Marzo, Giuseppe A; Gavin, Patricia; Davila, Alfonso F; Tornabene, Livio L; Bishop, Janice L; Roush, Ted L; Gross, Christoph; Kneissl, Thomas; Uceda, Esther R; Dohm, James M; Schulze-Makuch, Dirk; Rodríguez, J Alexis P; Amils, Ricardo; McKay, Christopher P
2010-07-06
Hundreds of impact craters on Mars contain diverse phyllosilicates, interpreted as excavation products of preexisting subsurface deposits following impact and crater formation. This has been used to argue that the conditions conducive to phyllosilicate synthesis, which require the presence of abundant and long-lasting liquid water, were only met early in the history of the planet, during the Noachian period (> 3.6 Gy ago), and that aqueous environments were widespread then. Here we test this hypothesis by examining the excavation process of hydrated minerals by impact events on Mars and analyzing the stability of phyllosilicates against the impact-induced thermal shock. To do so, we first compare the infrared spectra of thermally altered phyllosilicates with those of hydrated minerals known to occur in craters on Mars and then analyze the postshock temperatures reached during impact crater excavation. Our results show that phyllosilicates can resist the postshock temperatures almost everywhere in the crater, except under particular conditions in a central area in and near the point of impact. We conclude that most phyllosilicates detected inside impact craters on Mars are consistent with excavated preexisting sediments, supporting the hypothesis of a primeval and long-lasting global aqueous environment. When our analyses are applied to specific impact craters on Mars, we are able to identify both pre- and postimpact phyllosilicates, therefore extending the time of local phyllosilicate synthesis to post-Noachian times.
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Basaltic rocks analyzed by the Spirit rover in Gusev crater
McSween, H.Y.; Arvidson, R. E.; Bell, J.F.; Blaney, D.; Cabrol, N.A.; Christensen, P.R.; Clark, B. C.; Crisp, J.A.; Crumpler, L.S.; Des Marias, D.J.; Farmer, J.D.; Gellert, Ralf; Ghosh, A.; Gorevan, S.; Graff, T.; Grant, J.; Haskin, L.A.; Herkenhoff, K. E.; Johnson, J. R.; Jolliff, B.L.; Klingelhoefer, G.; Knudson, A.T.; McLennan, S.; Milam, K.A.; Moersch, J.E.; Morris, R.V.; Rieder, R.; Ruff, S.W.; De Souza, P.A.; Squyres, S. W.; Wanke, H.; Wang, A.; Wyatt, M.B.; Yen, A.; Zipfel, J.
2004-01-01
The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and Mini-Thermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain ???25% megacrysts. Chemical analyses of rocks by the Alpha Particle X-ray Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagioclase, and accessory FeTi oxides. Mo??ssbauer, Pancam, and Mini-TES spectra confirm the presence of olivine, magnetite, and probably pyroxene. These basalts extend the known range of rock compositions composing the martian crust.
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Physics of soft impact and cratering
Katsuragi, Hiroaki
2016-01-01
This book focuses on the impact dynamics and cratering of soft matter to describe its importance, difficulty, and wide applicability to planetary-related problems. A comprehensive introduction to the dimensional analysis and constitutive laws that are necessary to discuss impact mechanics and cratering is first provided. Then, particular coverage is given to the impact of granular matter, which is one of the most crucial constituents for geophysics. While granular matter shows both solid-like and fluid-like behaviors, neither solid nor fluid dynamics is sufficient to fully understand the physics of granular matter. In order to reveal its fundamental properties, extensive impact tests have been carried out recently. The author reveals the findings of these recent studies as well as what remains unsolved in terms of impact dynamics. Impact crater morphology with various soft matter impacts also is discussed intensively. Various experimental and observational results up to the recent Itokawa asteroid’s terrain...
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Crater monitoring through social media observations
Gialampoukidis, I.; Vrochidis, S.; Kompatsiaris, I.
2017-09-01
We have collected more than one lunar image per two days from social media observations. Each one of the collected images has been clustered into two main groups of lunar images and an additional cluster is provided (noise) with pictures that have not been assigned to any cluster. The proposed lunar image clustering process provides two classes of lunar pictures, at different zoom levels; the first showing a clear view of craters grouped into one cluster and the second demonstrating a complete view of the Moon at various phases that are correlated with the crawling date. The clustering stage is unsupervised, so new topics can be detected on-the-fly. We have provided additional sources of planetary images using crowdsourcing information, which is associated with metadata such as time, text, location, links to other users and other related posts. This content has crater information that can be fused with other planetary data to enhance crater monitoring.
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Apollo 16 lunar module 'Orion' photographed from distance during EVA
1972-01-01
The Apollo 16 Lunar Module 'Orion' is photographed from a distance by Astronaut Chares M. Duke Jr., lunar module pilot, aboard the moving Lunar Roving Vehicle. Astronauts Duke and John W. Young, commander, were returing from the third Apollo 16 extravehicular activity (EVA-2). The RCA color television camera mounted on the LRV is in the foreground. A portion of the LRV's high-gain antenna is at top left.
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Planetary boundary layer and circulation dynamics at Gale Crater, Mars
Fonseca, Ricardo M.; Zorzano-Mier, María-Paz; Martín-Torres, Javier
2018-03-01
The Mars implementation of the Planet Weather Research and Forecasting (PlanetWRF) model, MarsWRF, is used here to simulate the atmospheric conditions at Gale Crater for different seasons during a period coincident with the Curiosity rover operations. The model is first evaluated with the existing single-point observations from the Rover Environmental Monitoring Station (REMS), and is then used to provide a larger scale interpretation of these unique measurements as well as to give complementary information where there are gaps in the measurements. The variability of the planetary boundary layer depth may be a driver of the changes in the local dust and trace gas content within the crater. Our results show that the average time when the PBL height is deeper than the crater rim increases and decreases with the same rate and pattern as Curiosity's observations of the line-of-sight of dust within the crater and that the season when maximal (minimal) mixing is produced is Ls 225°-315° (Ls 90°-110°). Thus the diurnal and seasonal variability of the PBL depth seems to be the driver of the changes in the local dust content within the crater. A comparison with the available methane measurements suggests that changes in the PBL depth may also be one of the factors that accounts for the observed variability, with the model results pointing towards a local source to the north of the MSL site. The interaction between regional and local flows at Gale Crater is also investigated assuming that the meridional wind, the dynamically important component of the horizontal wind at Gale, anomalies with respect to the daily mean can be approximated by a sinusoidal function as they typically oscillate between positive (south to north) and negative (north to south) values that correspond to upslope/downslope or downslope/upslope regimes along the crater rim and Mount Sharp slopes and the dichotomy boundary. The smallest magnitudes are found in the northern crater floor in a region that
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Laboratory and Field Investigations of Small Crater Repair Technologies
National Research Council Canada - National Science Library
Priddy, Lucy P; Tingle, Jeb S; McCaffrey, Timothy J; Rollings, Ray S
2007-01-01
.... This airfield damage repair (ADR) investigation consisted of laboratory testing of selected crater fill and capping materials, as well as full-scale field testing of small crater repairs to evaluate field mixing methods, installation...
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Postshot distribution and movement of radionuclides in nuclear crater ejecta
Energy Technology Data Exchange (ETDEWEB)
Koranda, John J; Martin, John R; Wikkerink, Robert; Stuart, Marshall [Bio-Medical Division, Lawrence Radiation Laboratory, University of California, Livermore, CA (United States)
1970-05-01
The distribution and postshot movement of radionuclides in nuclear crater ejecta are discussed in this report. Continuing studies of tritium movement in ejecta at SEDAN crater demonstrate that variations in tritium concentration are correlated with seasonal rainfall and soil water movements. Losses of 27 mCi H{sup 3}/ft{sup 2} are evident on SEDAN crater lip at the end of a three year period of measurements in -which an unusually large flux of rain was received. The distribution of gamma emitting radionuclides and tritium is described in the recently created SCHOONER crater ejecta field. The specific activity of radionuclides in the SCHOONER ejecta continuum is shown for ejecta collected from the crater lip to 17 miles from GZ. The movement of W{sup 181} and tritium into the sub-ejecta preshot soil is described at a site 3000 feet from GZ. (author)
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2006-01-01
The Shuttle Radar Topography Mission (SRTM), flown aboard Space Shuttle Endeavour in February 2000, acquired elevation measurements for nearly all of Earth's landmass between 60oN and 56oS latitudes. For many areas of the world SRTM data provide the first detailed three-dimensional observation of landforms at regional scales. SRTM data were used to generate this view of the Crater Highlands along the East African Rift in Tanzania. Landforms are depicted with colored height and shaded relief, using a vertical exaggeration of 2X and a southwestwardly look direction. Lake Eyasi is depicted in blue at the top of the image, and a smaller lake occurs in Ngorongoro Crater. Near the image center, elevations peak at 3648 meters (11,968 feet) at Mount Loolmalasin, which is south of Ela Naibori Crater. Kitumbeine (left) and Gelai (right) are the two broad mountains rising from the rift lowlands. Mount Longido is seen in the lower left, and the Meto Hills are in the right foreground. Tectonics, volcanism, landslides, erosion and deposition -- and their interactions -- are all very evident in this view. The East African Rift is a zone of spreading between the African (on the west) and Somali (on the east) crustal plates. Two branches of the rift intersect here in Tanzania, resulting in distinctive and prominent landforms. One branch trends nearly parallel the view and includes Lake Eyasi and the very wide Ngorongoro Crater. The other branch is well defined by the lowlands that trend left-right across the image (below center, in green). Volcanoes are often associated with spreading zones where magma, rising to fill the gaps, reaches the surface and builds cones. Craters form if a volcano explodes or collapses. Later spreading can fracture the volcanoes, which is especially evident on Kitumbeine and Gelai Mountains (left and right, respectively, lower center). The Crater Highlands rise far above the adjacent savannas, capture moisture from passing air masses, and host rain
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Jozwiak, Lauren; Head, James; Neumann, G. A.; Wilson, Lionel
2017-01-01
Floor-fractured craters are a class of lunar crater hypothesized to form in response to the emplacement of a shallow magmatic intrusion beneath the crater floor. The emplacement of a shallow magmatic body should result in a positive Bouguer anomaly relative to unaltered complex craters, a signal which is observed for the average Bouguer anomaly interior to the crater walls. We observe the Bouguer anomaly of floor-fractured craters on an individual basis using the unfiltered Bouguer gravity so...
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A Numerical Investigation into Low-Speed Impact Cratering Events
Schwartz, Stephen; Richardson, D. C.; Michel, P.
2012-10-01
Impact craters are the geological features most commonly observed on the surface of solid Solar System bodies. Crater shapes and features are crucial sources of information regarding past and present surface environments, and can provide indirect information about the internal structures of these bodies. In this study, we consider the effects of low-speed impacts into granular material. Studies of low-speed impact events are suitable for understanding the cratering process leading, for instance, to secondary craters. In addition, upcoming asteroid sample return missions will employ surface sampling strategies that use impacts into the surface by a projectile. An understanding of the process can lead to better sampling strategies. We use our implementation of the Soft-Sphere Discrete Element Method (SSDEM) (Schwartz et al. 2012, Granular Matter 14, 363-380) into the parallel N-body code PKDGRAV (cf. Richardson et al. 2011, Icarus 212, 427-437) to model the impact cratering process into granular material. We consider the effects of boundary conditions on the ejecta velocity profile and discuss how results relate to the Maxwell Z-Model during the crater growth phase. Cratering simulations are compared to those of Wada et al. 2006 (Icarus 180, 528-545) and to impact experiments performed in conjunction with Hayabusa 2. This work is supported in part by grants from the National Science Foundation under grant number AST1009579 and from the Office of Space Science of NASA under grant number NNX08AM39G. Part of this study resulted from discussions with the International Team (#202) sponsored by ISSI in Bern (Switzerland). Some simulations were performed on the YORP cluster administered by the Center for Theory and Computation of the Department of Astronomy at the University of Maryland in College Park and on the SIGGAM computer cluster hosted by the Côte d'Azur Observatory in Nice (France).
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Apollo 11 Command Service Module
1969-01-01
A close-up view of the Apollo 11 command service module ready to be mated with the spacecraft LEM adapter of the third stage. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.
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Łukasiewicz, Kinga; Sanak, Marek; Węgrzyn, Grzegorz
2016-05-01
Various insects contain maternally inherited endosymbiotic bacteria which can cause reproductive alterations, modulation of some physiological responses (like immunity, heat shock response, and oxidative stress response), and resistance to viral infections. In butterflies, Wolbachia sp. is the most frequent endosymbiont from this group, occurring in about 30 % of species tested to date. In this report, the presence of Wolbachia-specific DNA has been detected in apollo butterfly (Parnassius apollo). In the isolated population of this insect occurring in Pieniny National Park (Poland), malformed individuals with deformed or reduced wings appear with an exceptionally high frequency. Interestingly, while total DNA isolated from most (about 85 %) normal insects contained Wolbachia-specific sequences detected by PCR, such sequences were absent in a large fraction (70 %) of individuals with deformed wings and in all tested individuals with reduced wings. These results indicate for the first time the correlation between malformation of wings and the absence of Wolbachia sp. in insects. Although the lack of the endosymbiotic bacteria cannot be considered as the sole cause of the deformation or reduction of wings, one might suggest that Wolbachia sp. could play a protective role in the ontogenetic development of apollo butterfly.
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Crater Lake Controls on Volcano Stability: Insights From White Island, New Zealand
Hamling, Ian J.
2017-11-01
Many volcanoes around the world host summit crater lakes but their influence on the overall stability of the edifice remains poorly understood. Here I use satellite radar data acquired by TerraSAR-X from early 2015 to July 2017 over White Island, New Zealand, to investigate the interaction of the crater lake and deformation of the surrounding edifice. An eruption in April 2016 was preceded by a period of uplift within the crater floor and drop in the lake level. Modeling of the uplift indicates a shallow source located at ˜100 m depth in the vicinity of the crater lake, likely coinciding with the shallow hydrothermal system. In addition to the drop in the lake level, stress changes induced by the inflation suggest that the pressurization of the shallow hydrothermal system helped promote failure along the edge of the crater lake which collapsed during the eruption. After the eruption, and almost complete removal of the crater lake, large areas of the crater wall and lake edge began moving downslope at rates approaching 400 mm/yr. The coincidence between the rapid increase in the displacement rates and removal of the crater lake suggests that the lake provides a physical control on the stability of the surrounding edifice.
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Role of impact cratering for Mars sample return
International Nuclear Information System (INIS)
Schultz, P.H.
1988-01-01
The preserved cratering record of Mars indicates that impacts play an important role in deciphering Martian geologic history, whether as a mechanism to modify the lithosphere and atmosphere or as a tool to sample the planet. The various roles of impact cratering in adding a broader understanding of Mars through returned samples are examined. Five broad roles include impact craters as: (1) a process in response to a different planetary localizer environment; (2) a probe for excavating crustal/mantle materials; (3) a possible localizer of magmatic and hydrothermal processes; (4) a chronicle of changes in the volcanic, sedimentary, atmospheric, and cosmic flux history; and (5) a chronometer for extending the geologic time scale to unsampled regions. The evidence for Earth-like processes and very nonlunar styles of volcanism and tectonism may shift the emphasis of a sampling strategy away from equally fundamental issues including crustal composition, unit ages, and climate history. Impact cratering not only played an important active role in the early Martian geologic history, it also provides an important tool for addressing such issues
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Apollo 12 feldspathic basalts 12031, 12038, and 12072; petrology, comparison and interpretations
International Nuclear Information System (INIS)
Beaty, E.W.; Hill, S.M.R.; Albee, A.L.; Baldridge, W.S.
1979-01-01
Modal and chemical data indicate that 12072, 12038, and 12031, the Apollo 12 feldspathic basalts, form a well-defined group which cannot be related to the other Apollo 12 rock types. 12072 contains phenocrysts of olivine and pigeonite and microphenocrysts of Cr-spinel set in a fine-grained, variolitic groundmass. 12038 is a medium-grained, equigranular basalt with a texture indicating it was multiply saturated. 12031 is a coarse-grained rock with granular to graphic intergrowths of pyroxene and plagioclase; it was also multiply saturated. Petrologic observations, as well as the bulk chemistry, are consistent with the interpretation that 12031 could be derived from 12072 through fractionation of Cr-spinel, olivine, and pigeonite, the observed phenocryst assemblage. 12038, however, contains more pigeonite, less olivine, three times as much Ca-phosphate minerals, one-fifth as much troilite, and much more sodic plagioclase than 12072. These differences indicate that 12038 must have come from a separate igneous body. Consideration of the bulk compositions indicates that neither 12072 and 12031 nor 12038 could have been derived from the Apollo 12 olivine, pigeonite, or ilmenite basalts by crystal--liquid fractionation. The general petrologic similarities between 12072, 12031, and the other Apollo 12 basalts suggests that they were produced in either the same or similar source regions. 12038, however, is petrologically and chemically unique, and is probably exotic to the Apollo 12 landing site
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Site characterization requirements for nuclear-cratering design
International Nuclear Information System (INIS)
Terhune, R.W.; Carlson, R.C.
1977-01-01
A material properties measurement program for the design of large engineering nuclear-excavation projects by computer calculation is presented. Material properties of the site and their relative effect on crater size are analyzed and ordered in relation to their importance in determining the overall cratering efficiency. The measurement program includes both in situ logging and laboratory measurement of core samples, together with the reason for each measurement and its use in the calculations
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Leight, C.; Fassett, C. I.; Crowley, M. C.; Dyar, M. D.
2017-01-01
Two types of measurements of Mercury's surface topography were obtained by the MESSENGER (MErcury Surface Space ENvironment, GEochemisty and Ranging) spacecraft: laser ranging data from Mercury Laser Altimeter (MLA) [1], and stereo imagery from the Mercury Dual Imaging System (MDIS) camera [e.g., 2, 3]. MLA data provide precise and accurate elevation meaurements, but with sparse spatial sampling except at the highest northern latitudes. Digital terrain models (DTMs) from MDIS have superior resolution but with less vertical accuracy, limited approximately to the pixel resolution of the original images (in the case of [3], 15-75 m). Last year [4], we reported topographic measurements of craters in the D=2.5 to 5 km diameter range from stereo images and suggested that craters on Mercury degrade more quickly than on the Moon (by a factor of up to approximately 10×). However, we listed several alternative explanations for this finding, including the hypothesis that the lower depth/diameter ratios we observe might be a result of the resolution and accuracy of the stereo DTMs. Thus, additional measurements were undertaken using MLA data to examine the morphometry of craters in this diameter range and assess whether the faster crater degradation rates proposed to occur on Mercury is robust.
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Floor-fractured craters on the Moon: an evidence of past intrusive magmatic activity
Thorey, C.; Michaut, C.
2012-12-01
Floor-fractured lunar craters (FFC's) are a class of craters modified by post impact mechanisms. They are defined by distinctive shallow, often plate-like or convex floors, wide floor moats and radial, concentric and polygonal floor-fractures, suggesting an endogenous process of modification. Two main mechanisms have been proposed to account for such observations : 1) viscous relaxation and 2) spreading of magmatic intrusions at depth below the crater. Here, we propose to test the case of magmatic intrusions. We develop a model for the dynamics of magma spreading below an elastic crust with a crater-like topography and above a rigid horizontal surface. Results show first that the lithostatic pressure increase at the crater rim prevents the intrusion from spreading horizontally giving rise to intrusion thickening and to an uplift of the crater floor. Second, the deformation of the overlying crust exerts a strong control on the intrusion shape, and hence, on the nature of the crater floor uplift. As the deformation can only occur over a minimum flexural wavelength noted Λ, the intrusion shape shows a bell-shaped geometry for crater radius smaller than 3Λ, or a flat top with smooth edges for crater radius larger than 3Λ. For given crustal elastic properties, the crust flexural wavelength increases with the intrusion depth. Therefore, for a large intrusion depth or small crater size, we observe a convex uplift of the crater floor. On the contrary, for a small intrusion depth or large crater size, the crater floor undergoes a piston-like uplift and a circular moat forms just before the rim. The depth of the moat is controlled by the thickening of the crust at the crater rim. On the contrary to viscous relaxation models, our model is thus able to reproduce most of the features of FFC's, including small-scale features. Spreading of a magmatic intrusion at depth can thus be considered as the main endogenous mechanism at the origin of the deformations observed at FFC
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East Part of Sapas Mons with Flooded Crater
1991-01-01
This Magellan image centered near 9.6 degrees north latitude, 189.5 degrees east longitude of an area 140 kilometers (87 miles) by 110 kilometers (68 miles) covers part of the eastern flank of the volcano Sapas Mons on the western edge of Atla Regio. The bright lobate features along the southern and the western part of the image, oriented in northeast to southwest directions, are lava flows that are rough at the 12.6 centimeter wavelength of the radar. These flows range in width from 5 kilometers to 25 kilometers (3 to 16 miles) with lengths of 50 kilometers to 100 kilometers (31 to 62 miles), extending off the area shown here. Additional radar-dark (smooth) flows are also present. The radar-bright linear structures in the northwest part of the image are interpreted to be faults and fractures possibly associated with the emplacement of magma in the subsurface. Located near the center of the image is a 20 kilometer (12 mile) diameter impact crater. This crater is superimposed on a northeast/southwest trending fracture while the southern part of the crater's ejecta blanket is covered by a 6 kilometer (4 mile) wide radar-bright lava flow. These relations indicate that the crater post dates an episode of fracturing and is older than the lava flows covering its southern edge. This is one of only a few places on Venus in which an impact crater is seen to be covered by volcanic deposits.
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Floor-Fractured Craters on Ceres and Implications for Internal Composition and Processes
Buczkowski, D.; Schenk, P.; Scully, J. E. C.; Park, R. S.; Preusker, F.; Raymond, C. A.; Russell, C. T.
2016-12-01
Several of the impact craters on Ceres have patterns of fractures on their floors. These fractures appear similar to those found within a class of lunar craters referred to as Floor-Fractured Craters (FFCs) [1]. Lunar FFCs are characterized by anomalously shallow floors cut by radial, concentric, and/or polygonal fractures, and have been classified into crater classes, Types 1 through 6, based on their morphometric properties [1,2]. Models for their formation have included both floor uplift due to magmatic intrusion below the crater or floor shallowing due to viscous relaxation. However, the observation that the depth versus diameter (d/D) relationship of the FFCs is distinctly shallower than the same association for other lunar craters supports the hypotheses that the floor fractures form due to shallow magmatic intrusion under the crater [2]. We have cataloged the Ceres FFCs according to the classification scheme designed for the Moon. Large (>50 km) Ceres FFCs are most consistent with Type 1 lunar FFCs, having deep floors, central peaks, wall terraces, and radial and/or concentric fractures. Smaller craters on Ceres are more consistent with Type 4 lunar FFCs, having less-pronounced floor fractures and v-shaped moats separating the wall scarp from the crater interior. An analysis of the d/D ratio for Ceres craters shows that, like lunar FFCs, the Ceres FFCs are anomalously shallow. This suggests that the fractures on the floor of Ceres FFCs may be due the intrusion of a low-density material below the craters that is uplifting their floors. While on the Moon the intrusive material is hypothesized to be silicate magma, this is unlikely for Ceres. However, a cryovolcanic extrusive edifice has been identified on Ceres [3], suggesting that cryomagmatic intrusions could be responsible for the formation of the Ceres FFCs. References: [1] Schultz P. (1976) Moon, 15, 241-273 [2] Jozwiak L.M. et al (2015) JGR 117, doi: 10.1029/2012JE004134 [3] Ruesch O. et al (2016
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Prediction of gamma exposure rates in large nuclear craters
Energy Technology Data Exchange (ETDEWEB)
Tami, Thomas M; Day, Walter C [U.S. Army Engineer Nuclear Cratering Group, Lawrence Radiation Laboratory, Livermore, CA (United States)
1970-05-15
In many civil engineering applications of nuclear explosives there is the need to reenter the crater and lip area as soon as possible after the detonation to carry out conventional construction activities. These construction activities, however, must be delayed until the gamma dose rate, or exposure rate, in and around the crater decays to acceptable levels. To estimate the time of reentry for post-detonation construction activities, the exposure rate in the crater and lip areas must be predicted as a function of time after detonation. An accurate prediction permits a project planner to effectively schedule post-detonation activities.
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Enhancing Magnetic Interpretation Towards Meteorite Impact Crater at Bukit Bunuh, Perak, Malaysia
Nur Amalina, M. K. A.; Nordiana, M. M.; Saad, Rosli; Saidin, Mokhtar
2017-04-01
Bukit Bunuh is the most popular area of suspected meteorite impact crater. In the history of meteorite impact hitting the earth, Bukit Bunuh has complex crater of a rebound zone of positive magnetic anomaly value. This study area was located at Lenggong, Perak of peninsular Malaysia. The crater rim extended 5 km outwards with a clear subdued zone and immediately surround by a positive magnetic residual crater rim zone. A recent study was done to enhance the magnetic interpretation towards meteorite impact crater on this study area. The result obtained is being correlated with boreholes data to determine the range of local magnetic value. For the magnetic survey, the equipment used is Geometric G-856 Proton Precision magnetometers with the aids of other tools such as compass and GPS. In advance, the using of proton precision magnetometer causes it able in measures the magnetic fields separately within interval of second. Also, 18 boreholes are accumulated at study area to enhance the interpretation. The additional boreholes data had successfully described the structure of the impact crater at Bukit Bunuh in detailed where it is an eroded impact crater. Correlations with borehole records enlighten the results acquired from magnetic methods to be more reliable. A better insight of magnetic interpretation of Bukit Bunuh impact crater was done with the aid of geotechnical methods.
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Detection and characterization of buried lunar craters with GRAIL data
Sood, Rohan; Chappaz, Loic; Melosh, Henry J.; Howell, Kathleen C.; Milbury, Colleen; Blair, David M.; Zuber, Maria T.
2017-06-01
We used gravity mapping observations from NASA's Gravity Recovery and Interior Laboratory (GRAIL) to detect, characterize and validate the presence of large impact craters buried beneath the lunar maria. In this paper we focus on two prominent anomalies detected in the GRAIL data using the gravity gradiometry technique. Our detection strategy is applied to both free-air and Bouguer gravity field observations to identify gravitational signatures that are similar to those observed over buried craters. The presence of buried craters is further supported by individual analysis of regional free-air gravity anomalies, Bouguer gravity anomaly maps, and forward modeling. Our best candidate, for which we propose the informal name of Earhart Crater, is approximately 200 km in diameter and forms part of the northwestern rim of Lacus Somniorum, The other candidate, for which we propose the informal name of Ashoka Anomaly, is approximately 160 km in diameter and lies completely buried beneath Mare Tranquillitatis. Other large, still unrecognized, craters undoubtedly underlie other portions of the Moon's vast mare lavas.
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Paradigm shifts about dust on the Moon: From Apollo 11 to Chang'e-4
O'Brien, Brian J.
2018-07-01
Strategic purposes of this DAP-2017 report are to update our DAP-2010 report on movements of inescapable fine lunar dust, to summarise key new measurements and to assist rigorous focus. Lunar dust is defined here in two sciences, Apollo dust and Ejecta dust, to end several confusions. The Kuhn Cycle is introduced to stimulate progression of a science about movements of Apollo dust which lacks an agreed paradigm to supply puzzles for scientists to solve and tools for their solution. We populate the cycle with two paradigm shifts. The first was serendipitous invention in 1966 of the Apollo Dust Detector Experiment (DDE), 3 orthogonal solar cells each with a thermometer, which on Apollo 12 measured cause and effect, collective movements of billions to trillions of low-energy Apollo dust particles and changes in temperature they cause. In contrast, Apollo 17 LEAM and LADEE LDEX experiments follow traditions to measure impacts of high-velocity Ejecta dust particles, one by one. In 2015, Apollo 12 DDE discoveries of sunrise-driven storms of Apollo dust stimulated a measurement-based 5-step model of dust transport at astronaut waist height. The discoveries solve (i) 50-year-old mysteries of Horizon Glow, (ii) 30-year-old uncertainties about levitated dust, (iii) processes leading to lunar surfaces being smooth and (iv) immobilisation of the Chang'e-3 lunar rover Yutu in 2014 after its first sunrise. The IAC-2017 Website Abstract of a withdrawn Chang'e-3 presentation may support our views that sunrise-mobilised dust caused immobilisation of Yutu. A precursor to a second paradigm shift was May 2016 announced revision of Chang'e-4 scientific priorities. Using Kuhn terminology of scientific progress, a second shift would follow our "revolution" in 2015 that sunrise-driven dust storms caused the 2014 ″crisis" of immobilisation of Chang'e-3 lunar rover Yutu. No such sequence occurred previously with lunar dust. Measurement-based evidence from Apollo 11 to Chang'e-3 confirms
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Computer-generated maps of lunar composition from gamma ray data
International Nuclear Information System (INIS)
Arnold, J.R.; Metzger, A.E.; Reedy, R.C.
1977-01-01
The system of Eliason and Soderblom (1977) has been used to process some of the gamma ray mapping data obtained on Apollo 15 and 16. Old results are confirmed and new information obtained, especially with respect to the distribution of Fe over the area mapped, and the correlation of Fe with the radioactive elements. The results are displayed
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Web Apollo: a web-based genomic annotation editing platform.
Lee, Eduardo; Helt, Gregg A; Reese, Justin T; Munoz-Torres, Monica C; Childers, Chris P; Buels, Robert M; Stein, Lincoln; Holmes, Ian H; Elsik, Christine G; Lewis, Suzanna E
2013-08-30
Web Apollo is the first instantaneous, collaborative genomic annotation editor available on the web. One of the natural consequences following from current advances in sequencing technology is that there are more and more researchers sequencing new genomes. These researchers require tools to describe the functional features of their newly sequenced genomes. With Web Apollo researchers can use any of the common browsers (for example, Chrome or Firefox) to jointly analyze and precisely describe the features of a genome in real time, whether they are in the same room or working from opposite sides of the world.
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The Apollo experiment for document delivery via satellite communication
1985-03-01
Dutch participation possibilities in the Apollo document delivery project, wishes and idea's of potential user and tender groups, and plans and activities of Dutch institutes and companies, are surveyed. The Apollo storage and transport system, demand and administration network, potential markets, and subject areas of the documents are investigated. Utilization areas (scientific, technical, administration, and business information) are listed. High tariffs and the lack of necessary provision make a direct participation strategy impossible. However, in the experimental phase, Dutch companies must be allowed to contribute in technical developments and availability of organizational and technical facilities must be stimulated.
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Harland, David M
2009-01-01
In 'Paving the Way for Apollo 11' David Harland explains the lure of the Moon to classical philosophers, astronomers, and geologists, and how NASA set out to investigate the Moon in preparation for a manned lunar landing mission. It focuses particularly on the Lunar Orbiter and Surveyor missions.
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Verma, A.; Bourke, M. C.; Osinski, G.; Viles, H. A.; Blanco, J. D. R.
2017-12-01
Impact cratering is an important geological process that affects all planetary bodies in our solar system. As rock breakdown plays an important role in the evolution of landforms and sediments, it is important to assess the role of inheritance in the subsequent breakdown of impacted rocks.The shock pressure of several gigapascals generated during the impact can exceed the effective strength of target lithology by three to four orders of magnitude and is responsible for melting, vaporisation, shock metamorphism, fracturing and fragmentation of rocks. Environmental conditions and heterogeneities in rock properties exert an important control in rock breakdown. Similar to other subaerial rocks, impacted rocks are affected by a range of rock breakdown processes. In order to better understand the role of inheritance of the impact on rock breakdown, a rock breakdown experiment was conducted in a simulated environmental cabinet under conditions similar to the arid conditions found at the Meteor Crater site. We sampled Moenkopi and Coconino Sandstone from the Meteor Crater impact site in Arizona. For comparison, samples were also collected at control sites close by that have similar rock formations but did not undergo impact. Several established techniques (X-ray CT, SEM, Equotip, SfM) were used to characterise the rock samples before the environmental cabinet experiments. Our laboratory analysis (XRD, SEM, optical microscopy, X-ray CT) on impacted rock samples from Meteor Crater, show that rock porosity and permeability changes due to compaction and fracturing during impact. There were no high-pressure polymorphs of quartz or glass detected in XRD analysis. We ran the experiments on a total of 28 petrophysically characterised 5x5x5 cm sample blocks of Coconino and Moenkopi Sandstone (24 impacted rocks and 4 non-impacted). The results will be presented at the AGU Fall meeting 2017.
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Apollo 11 Astronaut Neil Armstrong Performs Ladder Practice
1969-01-01
In preparation of the nation's first Lunar landing mission, Apollo 11 crew members underwent training activities to practice activities they would be performing during the mission. In this photograph, Neil Armstrong, donned in his space suit, practices getting back to the first rung of the ladder on the Lunar Module (LM). The Apollo 11 mission launched from the Kennedy Space Center (KSC) in Florida via the Marshall Space Flight Center (MSFC) developed Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. Aboard the space craft were astronauts Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. (Buzz) Aldrin Jr., Lunar Module (LM) pilot. The CM, 'Columbia', piloted by Collins, remained in a parking orbit around the Moon while the LM, 'Eagle'', carrying astronauts Armstrong and Aldrin, landed on the Moon. On July 20, 1969, Armstrong was the first human to ever stand on the lunar surface, followed by Aldrin. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. With the success of Apollo 11, the national objective to land men on the Moon and return them safely to Earth had been accomplished.
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Apollo 11 Astronaut Neil Armstrong Approaches Practice Helicopter
1969-01-01
In preparation of the nation's first lunar landing mission, Apollo 11, crew members underwent training to practice activities they would be performing during the mission. In this photograph Neil Armstrong approaches the helicopter he flew to practice landing the Lunar Module (LM) on the Moon. The Apollo 11 mission launched from the Kennedy Space Center (KSC) in Florida via the Marshall Space Flight Center (MSFC) developed Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. Aboard the space craft were astronauts Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. (Buzz) Aldrin Jr., Lunar Module (LM) pilot. The CM, 'Columbia', piloted by Collins, remained in a parking orbit around the Moon while the LM, 'Eagle'', carrying astronauts Armstrong and Aldrin, landed on the Moon. On July 20, 1969, Armstrong was the first human to ever stand on the lunar surface, followed by Aldrin. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. With the success of Apollo 11, the national objective to land men on the Moon and return them safely to Earth had been accomplished
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Brushed Target on Rock 'Champagne' in Gusev Crater
2005-01-01
NASA's Mars Exploration Rover Spirit took this microscopic image of a target called 'Bubbles' on a rock called 'Champagne' after using its rock abrasion tool to brush away a coating of dust. The circular brushed area is about 5 centimeters (2 inches) across. This rock is different from rocks out on the plains of Gusev Crater but is similar to other rocks in this area of the 'Columbia Hills' in that it has higher levels of phosphorus. Plagioclase, a mineral commonly found in igneous rocks, is also present in these rocks, according to analysis with the minature thermal emission spectrometer. By using the alpha particle X-ray spectrometer to collect data over multiple martian days, or sols, scientists are also beginning to get measurements of trace elements in these rocks. Spirit took the images that are combined into this mosaic on sol 354 (Dec. 30, 2004).
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International Nuclear Information System (INIS)
Carlos, B.A.; Bish, D.L.; Chipera, S.J.
1990-07-01
The Crater Flat Tuff is almost entirely below the water table in drill hole USW G-4 at Yucca Mountain, Nevada. Manganese-oxide minerals from the Crater Flat Tuff in USW G-4 were studied using optical, scanning electron microscopic, electron microprobe, and x-ray powder diffraction methods to determine their distribution, mineralogy, and chemistry. Manganese-oxide minerals coat fractures in all three members of the Crater Flat Tuff (Prow Pass, Bullfrog, and Tram), but they are most abundant in fractures in the densely welded devitrified intervals of these members. The coatings are mostly of the cryptomelane/hollandite mineral group, but the chemistry of these coatings varies considerably. Some of the chemical variations, particularly the presence of calcium, sodium, and strontium, can be explained by admixture with todorokite, seen in some x-ray powder diffraction patterns. Other chemical variations, particularly between Ba and Pb, demonstrate that considerable substitution of Pb for Ba occurs in hollandite. Manganese-oxide coatings are common in the 10-m interval that produced 75% of the water pumped from USW G-4 in a flow survey in 1983. Their presence in water-producing zones suggests that manganese oxides may exert a significant chemical effect on groundwater beneath Yucca Mountain. In particular, the ability of the manganese oxides found at Yucca Mountain to be easily reduced suggests that they may affect the redox conditions of the groundwater and may oxidize dissolved or suspended species. Although the Mn oxides at Yucca Mountain have low exchange capacities, these minerals may retard the migration of some radionuclides, particularly the actinides, through scavenging and coprecipitation. 23 refs., 21 figs., 2 tabs
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Geomorphometric analysis of selected Martian craters using polar coordinate transformation
Magyar, Zoltán; Koma, Zsófia; Székely, Balázs
2016-04-01
Centrally symmetric landform elements are very common features on the surface of the planet Mars. The most conspicuous ones of them are the impact craters of various size. However, a closer look on these features reveals that they show often asymmetric patterns as well. These are partially related to the geometry of the trajectory of the impacting body, but sometimes it is a result of surface processes (e.g., freeze/thaw cycles, mass movements). Geomorphometric studies have already been carried out to reveal these pecularities. Our approach, the application of polar coordinate transformation (PCT) very sensitively enhances the non-radial and non-circular shapes. We used digital terrain models (DTMs) derived from the ESA Mars Express HRSC imagery. The original DTM or its derivatives (e.g. slope angle or aspect) are PCT transformed. We analyzed the craters inter alia with scattergrams in polar coordinates. The resulting point cloud can be used directly for the analysis, but in some cases an interpolation should be applied to enhance certain non-circular features (especially in case of smaller craters). Visual inspection of the crater slopes, coloured by the aspect, reveals smaller features. Some of them are processing artefacts, but many of them are related to local undulations in the topography or indications of mass movements. In many cases the undulations of the crater rim are due to erosional processes. The drawbacks of the technology are related to the uneven resolution of the projected image: features in the crater centre should be left out from the analysis because PCT has a low resolution around the projection center. Furthermore, the success of the PCT depends on the correct definition of the projection centre: erroneously centered images are not suitable for analysis. The PCT transformed images are also suitable for radial averaging and calculation of standard deviations, resulting in typical, comparable craters shapes. These studies may lead to a deeper
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Long-Term Recovery of Life in the Chicxulub Crater
Lowery, C.; Jones, H.; Bralower, T. J.; Smit, J.; Rodriguez-Tovar, F. J.; Whalen, M. T.; Owens, J. D.; Expedition 364 Science Party, I. I.
2017-12-01
The Chicxulub Crater on the Yucatán Peninsula of Mexico was formed by the impact of an asteroid 66 Ma that caused the extinction of 75% of genera on Earth. Immediately following the impact, the decimated ecosystem began the long process of recovery, both in terms of primary productivity and species diversity. This well-documented process was heterogeneous across the world ocean, but until the present time it has been inaccessible at ground zero of the impact. IODP/ICDP Exp. 364 recovered 9.5 m of pelagic limestone spanning the entire Paleocene, including a continuous section spanning the first 5 myr following the impact. The Chicxulub Crater is the largest known marine impact crater on Earth, and the recovery of the ecosystem presented here is the first such record of long-term primary succession in the sterile zone of a large impact crater. Planktic and benthic foraminifera, calcareous nannoplankton, calcispheres, bioturbation, and geochemical proxies all indicate that export productivity in the Chicxulub Crater recovered rapidly (within 30 kyr) following the impact. Recovery in terms of diversity and species abundance took much longer, and varied between groups. Planktic foraminifera quickly diversified, with all common Paleocene tropical/subtropical species appearing roughly when expected. Trace fossils appear rapidly after the event, with a progressive recovery through the lowermost Paleocene. Calcareous nannoplankton took much longer to recover, and disaster taxa like Braarudosphaera dominated the assemblage well into the late Paleocene. Paleoecology and geochemistry relate these trends to oceanographic conditions within the Chicxulub Crater. Planktic foraminifera from known depth habitats, including Morozovellids, Acarininids, Chiloguembelinids, and Subbotinids, track changes in the water column structure and paleoredox conditions within the crater. Diverse and abundant macro- and microbenthic organisms indicate food availability and good oxygen conditions
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Relaxed impact craters on Ganymede: Regional variation and high heat flows
Singer, Kelsi N.; Bland, Michael T.; Schenk, Paul M.; McKinnon, William B.
2018-05-01
Viscously relaxed craters provide a window into the thermal history of Ganymede, a satellite with copious geologic signs of past high heat flows. Here we present measurements of relaxed craters in four regions for which suitable imaging exists: near Anshar Sulcus, Tiamat Sulcus, northern Marius Regio, and Ganymede's south pole. We describe a technique to measure apparent depth, or depth of the crater with respect to the surrounding terrain elevation. Measured relaxation states are compared with results from finite element modeling to constrain heat flow scenarios [see companion paper: Bland et al. (2017)]. The presence of numerous, substantially relaxed craters indicates high heat flows-in excess of 30-40 mW m-2 over 2 Gyr, with many small (heat flows. Crater relaxation states are bimodal for some equatorial regions but not in the region studied near the south pole, which suggests regional variations in Ganymede's thermal history.
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Mars Climate History: Insights From Impact Crater Wall Slope Statistics
Kreslavsky, Mikhail A.; Head, James W.
2018-02-01
We use the global distribution of the steepest slopes on crater walls derived from Mars Orbiter Laser Altimeter profile data to assess the magnitudes of degradational processes with latitude, altitude, and time. We independently confirm that Amazonian polar/high-latitude crater slope modification is substantial, but that craters in the low latitudes have essentially escaped significant slope modification since the Early Hesperian. We find that the total amount of crater wall degradation in the Late Noachian is very small in comparison to the circumpolar regions in the Late Amazonian, an observation that we interpret to mean that the Late Noachian climate was not characterized by persistent and continuous warm and wet conditions. A confirmed elevational zonality in degradation in the Early Hesperian is interpreted to mean that the atmosphere was denser than today.
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Launch of Apollo 8 lunar orbit mission
1968-01-01
The Apollo 8 (Spacecraft 103/Saturn 503) space vehicle launched from Pad A, Launch Complex 39, Kennedy Space Center, at 7:51 a.m., December 21, 1968. In this view there is water in the foreground and seagulls.
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International Nuclear Information System (INIS)
Iriyama, Jun; Honda, Masatake.
1979-01-01
From the cosmic-ray exposure age data, (time scale 10 7 - 10 8 years), of the lunar surface materials, we discuss the gardening process of the lunar surface layer caused by the meteoroid impact cratering. At steady state, it is calculated that, in the region within 10 - 50 m of the surface, a mixing rate of 10 -4 to 10 -5 mm/yr is necessary to match the exposure ages. Observed exposure ages of the lunar samples could be explained by the gardening effect calculated using a crater formation rate which is slightly modified from the current crater population data. (author)
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Deposition, exhumation, and paleoclimate of an ancient lake deposit, Gale crater, Mars
Grotzinger, J. P.; Gupta, S.; Malin, M. C.; Rubin, D. M.; Schieber, J.; Siebach, K.; Sumner, D. Y.; Stack, K. M.; Vasavada, A. R.; Arvidson, R. E.; Calef, F.; Edgar, L.; Fischer, W. F.; Grant, J. A.; Griffes, J.; Kah, L. C.; Lamb, M. P.; Lewis, K. W.; Mangold, N.; Minitti, M. E.; Palucis, M.; Rice, M.; Williams, R. M. E.; Yingst, R. A.; Blake, D.; Blaney, D.; Conrad, P.; Crisp, J.; Dietrich, W. E.; Dromart, G.; Edgett, K. S.; Ewing, R. C.; Gellert, R.; Hurowitz, J. A.; Kocurek, G.; Mahaffy, P.; McBride, M. J.; McLennan, S. M.; Mischna, M.; Ming, D.; Milliken, R.; Newsom, H.; Oehler, D.; Parker, T. J.; Vaniman, D.; Wiens, R. C.; Wilson, S. A.
2015-10-01
The landforms of northern Gale crater on Mars expose thick sequences of sedimentary rocks. Based on images obtained by the Curiosity rover, we interpret these outcrops as evidence for past fluvial, deltaic, and lacustrine environments. Degradation of the crater wall and rim probably supplied these sediments, which advanced inward from the wall, infilling both the crater and an internal lake basin to a thickness of at least 75 meters. This intracrater lake system probably existed intermittently for thousands to millions of years, implying a relatively wet climate that supplied moisture to the crater rim and transported sediment via streams into the lake basin. The deposits in Gale crater were then exhumed, probably by wind-driven erosion, creating Aeolis Mons (Mount Sharp).
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Parnassiana nova : XLVII. Neue Unterarten von Parnassius apollo L. und Parnassius mnemosyne L.
Eisner, C.
1974-01-01
1. DREI NEUE PARNASSIUS APOLLO L. UNTERARTEN AUS SPANIEN Die Herren P. Capdeville und P. C. Rougeot haben in den letzten Jahren die verschiedenen Flugplätze von Parnassius apollo L. in Spanien aufgesucht und eine Anzahl neuer Unterarten aufgestellt. Die Kenntnis wird ergänzt durch die Beschreibung
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[Study of enhancement effect of laser-induced crater on plasma radiation].
Chen, Jin-Zhong; Zhang, Xiao-Ping; Guo, Qing-Lin; Su, Hong-Xin; Li, Guang
2009-02-01
Single pulses exported from high-energy neodymium glass laser were used to act on the same position of soil sample surface repeatedly, and the plasma emission spectra generated from sequential laser pulse action were collected by spectral recording system. The experimental results show that the laser-induced soil plasma radiation was enhanced continuously under the confinement effect of the crater walls, and the line intensities and signal-to-background ratios both had different improvements along with increasing the number of acting pulses. The photographs of the plasma image and crater appearance were taken to study the plasma shape, laser-induced crater appearance, and the mass of the ablated sample. The internal mechanism behind that laser-induced crater enhanced plasma radiation was researched. Under the sequential laser pulse action, the forming plasma as a result enlarges gradually first, leading to distortion at the trail of plasma plume, and then, its volume diminishes slowly. And also, the color of the plasma changes from buff to white gradually, which implies that the temperature increases constantly. The laser-induced crater had a regular shape, that is, the diameter increased from its bottom to top gradually, thus forming a taper. The mass of the laser-ablated substance descends along with increasing the amount of action pulse. Atomization degree of vaporized substance was improved in virtue of the crater confinement effect, Fresnel absorption produced from the crater walls reflection, and the inverse bremsstrahlung, and the plasma radiation intensity was enhanced as a result.
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Apollo Lunar Module Electrical Power System Overview
Interbartolo, Michael
2009-01-01
Objectives include: a) Describe LM Electrical System original specifications; b) Describe the decision to change from fuel cells to batteries and other changes; c) Describe the Electrical system; and d) Describe the Apollo 13 failure from the LM perspective.
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Talpe Matthieu; Zuber, Maria T.; Yang, Di; Neumann, Gregory A.; Solomon, Sean C.; Mazarico, Erwan; Vilas, Faith
2012-01-01
Earth-based radar images of Mercury show radar-bright material inside impact craters near the planet s poles. A previous study indicated that the polar-deposit-hosting craters (PDCs) at Mercury s north pole are shallower than craters that lack such deposits. We use data acquired by the Mercury Laser Altimeter on the MESSENGER spacecraft during 11 months of orbital observations to revisit the depths of craters at high northern latitudes on Mercury. We measured the depth and diameter of 537 craters located poleward of 45 N, evaluated the slopes of the northern and southern walls of 30 PDCs, and assessed the floor roughness of 94 craters, including nine PDCs. We find that the PDCs appear to have a fresher crater morphology than the non-PDCs and that the radar-bright material has no detectable influence on crater depths, wall slopes, or floor roughness. The statistical similarity of crater depth-diameter relations for the PDC and non-PDC populations places an upper limit on the thickness of the radar-bright material (< 170 m for a crater 11 km in diameter) that can be refined by future detailed analysis. Results of the current study are consistent with the view that the radar-bright material constitutes a relatively thin layer emplaced preferentially in comparatively young craters.
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Cratering Studies in Thin Plastic Films
Shu, A. J.; Bugiel, S.; Gruen, E.; Hillier, J.; Horanyi, M.; Munsat, T. L.; Srama, R.
2013-12-01
Thin plastic films, such as Polyvinylidene Fluoride (PVDF), have been used as protective coatings or dust detectors on a number of missions including the Dust Counter and Mass Analyzer (DUCMA) instrument on Vega 1 and 2, the High Rate Detector (HRD) on the Cassini Mission, and the Student Dust Counter (SDC) on New Horizons. These types of detectors can be used on the lunar surface or in lunar orbit to detect dust grain size distributions and velocities. Due to their low power requirements and light weight, large surface area detectors can be built for observing low dust fluxes. The SDC dust detector is made up of a permanently polarized layer of PVDF coated on both sides with a thin layer (≈ 1000 Å) of aluminum nickel. The operation principle is that a micrometeorite impact removes a portion of the metal surface layer exposing the permanently polarized PVDF underneath. This causes a local potential near the crater changing the surface charge of the metal layer. The dimensions and shape of the crater determine the strength of the potential and thus the signal generated by the PVDF. The theoretical basis for signal interpretation uses a crater diameter scaling law which was not intended for use with PVDF. In this work, a crater size scaling law has been experimentally determined, and further simulation work is being done to enhance our understanding of the mechanisms of crater formation. LS-Dyna, a smoothed particle hydrodynamics (SPH) code from the Livermore Software Technology Corp. was chosen to simulate micrometeorite impacts. SPH is known to be well suited to the large deformities found in hypervelocity impacts. It is capable of incorporating key physics phenomena, including fracture, heat transfer, melting, etc. Furthermore, unlike Eulerian methods, SPH is gridless allowing large deformities without the inclusion of unphysical erosion algorithms. Material properties are accounted for using the Grüneisen Equation of State. The results of the SPH model can
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MAX: an expert system for running the modular transport code APOLLO II
International Nuclear Information System (INIS)
Loussouarn, O.; Ferraris, C.; Boivineau, A.
1990-01-01
MAX is an expert system built to help users of the APOLLO II code to prepare the input data deck to run a job. APOLLO II is a modular transport-theory code for calculating the neutron flux in various geometries. The associated GIBIANE command language allows the user to specify the physical structure and the computational method to be used in the calculation. The purpose of MAX is to bring into play expertise in both neutronic and computing aspects of the code, as well as various computational schemes, in order to generate automatically a batch data set corresponding to the APOLLO II calculation desired by the user. MAX is implemented on the SUN 3/60 workstation with the S1 tool and graphic interface external functions
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Relaxed impact craters on Ganymede: Regional variation and high heat flows
Singer, Kelsi N.; Bland, Michael T.; Schenk, Paul M.; McKinnon, William B.
2018-01-01
Viscously relaxed craters provide a window into the thermal history of Ganymede, a satellite with copious geologic signs of past high heat flows. Here we present measurements of relaxed craters in four regions for which suitable imaging exists: near Anshar Sulcus, Tiamat Sulcus, northern Marius Regio, and Ganymede's south pole. We describe a technique to measure apparent depth, or depth of the crater with respect to the surrounding terrain elevation. Measured relaxation states are compared with results from finite element modeling to constrain heat flow scenarios [see companion paper: Bland et al. (2017)]. The presence of numerous, substantially relaxed craters indicates high heat flows—in excess of 30–40 mW m−2 over 2 Gyr, with many small (heat flows. Crater relaxation states are bimodal for some equatorial regions but not in the region studied near the south pole, which suggests regional variations in Ganymede's thermal history.
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Ejecta from single-charge cratering explosions
Energy Technology Data Exchange (ETDEWEB)
Carlson, R H
1970-05-15
The objective was to obtain experimental data tracing the location of ejecta to its origin within the crater region. The experiment included ten high-explosive spherical charges weighing from 8 to 1000 pounds and detonated in a playa dry lake soil on the Tonopah Test Range. Each event included from 24 to 40 locations of distinctly different tracer material embedded in a plane in the expected crater region. Tracers consisted of glass, ceramic and bugle beads, chopped metal, and plastic wire. Results of this experiment yielded data on tracer dispersion as a function of charge weight, charge burial depth and tracer emplacement position. Tracer pattern parameters such as center-of-tracer mass, range to center-of-tracer mass, and angle to center-of-tracer mass were determined. There is a clear tendency for range (to center-of-tracer mass) and the size of the dispersion pattern to decrease as tracer emplacement depth increases. Increasing tracer emplacement depth and range tends to decrease the area over which tracers are dispersed on the ground surface. Tracers at the same scaled position relative to the charge were deposited closer to the crater (on a scaled basis) as charge weight was increased. (author)
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International Nuclear Information System (INIS)
Ford, J.P.
1989-01-01
Observations of small terrestrial craters by Seasat synthetic aperture radar (SAR) at high resolution (approx. 25 m) and of comparatively large Venusian craters by Venera 15/16 images at low resolution (1000 to 2000 m) and shorter wavelength show similarities in the radar responses to crater morphology. At low incidence angles, the responses are dominated by large scale slope effects on the order of meters; consequently it is difficult to locate the precise position of crater rims on the images. Abrupt contrasts in radar response to changing slope (hence incidence angle) across a crater produce sharp tonal boundaries normal to the illumination. Crater morphology that is radially symmetrical appears on images to have bilateral symmetry parallel to the illumination vector. Craters are compressed in the distal sector and drawn out in the proximal sector. At higher incidence angles obtained with the viewing geometry of SIR-A, crater morphology appears less compressed on the images. At any radar incidence angle, the distortion of a crater outline is minimal across the medial sector, in a direction normal to the illumination. Radar bright halos surround some craters imaged by SIR-A and Venera 15 and 16. The brightness probably denotes the radar response to small scale surface roughness of the surrounding ejecta blankets. Similarities in the radar responses of small terrestrial impact craters and volcanic craters of comparable dimensions emphasize the difficulties in discriminating an impact origin from a volcanic origin in the images. Similar difficulties will probably apply in discriminating the origin of small Venusian craters, if they exist. Because of orbital considerations, the nominal incidence angel of Magellan radar at the center of the imaging swath will vary from about 45 deg at 10 deg N latitude to about 16 deg at the north pole and at 70 deg S latitude. Impact craters and comparable volcanic landforms will show bilateral symmetry
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Deposition, exhumation, and paleoclimate of an ancient lake deposit, Gale crater, Mars.
Grotzinger, J P; Gupta, S; Malin, M C; Rubin, D M; Schieber, J; Siebach, K; Sumner, D Y; Stack, K M; Vasavada, A R; Arvidson, R E; Calef, F; Edgar, L; Fischer, W F; Grant, J A; Griffes, J; Kah, L C; Lamb, M P; Lewis, K W; Mangold, N; Minitti, M E; Palucis, M; Rice, M; Williams, R M E; Yingst, R A; Blake, D; Blaney, D; Conrad, P; Crisp, J; Dietrich, W E; Dromart, G; Edgett, K S; Ewing, R C; Gellert, R; Hurowitz, J A; Kocurek, G; Mahaffy, P; McBride, M J; McLennan, S M; Mischna, M; Ming, D; Milliken, R; Newsom, H; Oehler, D; Parker, T J; Vaniman, D; Wiens, R C; Wilson, S A
2015-10-09
The landforms of northern Gale crater on Mars expose thick sequences of sedimentary rocks. Based on images obtained by the Curiosity rover, we interpret these outcrops as evidence for past fluvial, deltaic, and lacustrine environments. Degradation of the crater wall and rim probably supplied these sediments, which advanced inward from the wall, infilling both the crater and an internal lake basin to a thickness of at least 75 meters. This intracrater lake system probably existed intermittently for thousands to millions of years, implying a relatively wet climate that supplied moisture to the crater rim and transported sediment via streams into the lake basin. The deposits in Gale crater were then exhumed, probably by wind-driven erosion, creating Aeolis Mons (Mount Sharp). Copyright © 2015, American Association for the Advancement of Science.
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Overview of the Atmosphere and Environment within Gale Crater on Mars
Vasavada, A. R.; Grotzinger, J. P.; Crisp, J. A.; Gomez-Elvira, J.; Mahaffy, P. R.; Webster, C. R.
2012-12-01
Curiosity's mission at Gale Crater places a number of highly capable atmospheric and environmental sensors within a dynamic setting: next to a 5-km mountain within a 150-km diameter impact crater whose floor is -4.5 km. Curiosity's scientific payload was chosen primarily to allow a geologic and geochemical investigation of Mars' environmental history and habitability, as preserved in the layered sediments on the crater floor and mound. Atmospheric and environmental sensors will contribute by measuring the bulk atmospheric chemical and isotopic composition, the flux of high-energy particle and ultraviolet radiation after modification by the atmosphere, and modern processes related to meteorology and climate over at least one Mars year. The Sample Analysis at Mars instrument will analyze the atmosphere with its mass spectrometer and tunable laser spectrometer. The former is capable of providing bulk composition and isotopic ratios of relevance to planetary evolution, such as nitrogen and noble gases. The latter is designed to acquire high-precision measurements of atmospheric species including CH4, CO2, and H2O, and key isotope ratios in H, C, and O. An important goal will be to compare CH4 abundance and time variability over the mission with the reported detections from the Mars Express orbiter and ground-based observations. The Radiation Assessment Detector (RAD) measures a broad spectrum of high-energy radiation incident at the surface, including secondary particles created via interactions of galactic cosmic rays and solar protons with Mars' atmospheric constituents. Curiosity's Rover Environmental Monitoring Station (REMS) carries six ultraviolet sensors, spanning 200-380 nm. For the first time, both the high-energy and ultraviolet radiation measured at the surface can be compared with measurements above the atmosphere, acquired by other platforms. Modern meteorology and the climatology of dust and water will be studied using the rover's cameras and REMS
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Rocket ranch the nuts and bolts of the Apollo Moon program at Kennedy Space Center
Ward, Jonathan H
2015-01-01
Jonathan Ward takes the reader deep into the facilities at Kennedy Space Center to describe NASA’s first computer systems used for spacecraft and rocket checkout and explain how tests and launches proceeded. Descriptions of early operations include a harrowing account of the heroic efforts of pad workers during the Apollo 1 fire. A companion to the author’s book Countdown to a Moon Launch: Preparing Apollo for Its Historic Journey, this explores every facet of the facilities that served as the base for the Apollo/Saturn missions. Hundreds of illustrations complement the firsthand accounts of more than 70 Apollo program managers and engineers. The era of the Apollo/Saturn missions was perhaps the most exciting period in American space exploration history. Cape Canaveral and Kennedy Space Center were buzzing with activity. Thousands of workers came to town to build the facilities and launch the missions needed to put an American on the Moon before the end of the decade. Work at KSC involved much more than j...
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Hypervelocity impact cratering calculations
Maxwell, D. E.; Moises, H.
1971-01-01
A summary is presented of prediction calculations on the mechanisms involved in hypervelocity impact cratering and response of earth media. Considered are: (1) a one-gram lithium-magnesium alloys impacting basalt normally at 6.4 km/sec, and (2) a large terrestrial impact corresponding to that of Sierra Madera.
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Results of examination of the calvarium, brain, and meninges. [in Apollo 17 BIOCORE pocket mice
Haymaker, W.; Zeman, W.; Turnbill, C. E.; Clayton, R. K.; Bailey, O. T.; Samorajski, T.; Vogel, F. S.; Lloyd, B.; Cruty, M. R.; Benton, E. V.
1975-01-01
Tissue reactions were found around the monitor (dosimeter) assemblies that had been implanted beneath the scalp of the five pocket mice that flew on Apollo XVII. Mitosis in the dentate gyrus of the hippocampal formation was considerably reduced in comparison with that in control animals. Otherwise the brain tissue as well as the meninges in the flight animals appeared unaltered. Since the animals were exposed primarily to high Z-high energy (HZE) cosmic-ray particles at the lower end of the high LET spectrum, the lack of changes in the brain cannot be taken as evidence that the brain will suffer no damage from the heavier HZE particles on prolonged manned missions.
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The Mechanics of Peak-Ring Impact Crater Formation from the IODP-ICDP Expedition 364
Melosh, H.; Collins, G. S.; Morgan, J. V.; Gulick, S. P. S.
2017-12-01
The Chicxulub impact crater is one of very few peak-ring impact craters on Earth. While small (less than 3 km on Earth) impact craters are typically bowl-shaped, larger craters exhibit central peaks, which in still larger (more than about 100 km on Earth) craters expand into mountainous rings with diameters close to half that of the crater rim. The origin of these peak rings has been contentious: Such craters are far too large to create in laboratory experiments and remote sensing of extraterrestrial examples has not clarified the mechanics of their formation. Two principal models of peak ring formation are currently in vogue, the "nested crater" model, in which the peak ring originates at shallow depths in the target, and the "dynamic collapse" model in which the peak ring is uplifted at the base of a collapsing, over-steepened central peak and its rocks originate at mid-crustal depths. IODP-ICDP Expedition 364 sought to elucidate, among other important goals, the mechanics of peak ring formation in the young (66 Myr), fresh, but completely buried Chicxulub impact crater. The cores from this borehole now show unambiguously that the rocks in the Chicxulub peak ring originated at mid-crustal depths, apparently ruling out the nested crater model. These rocks were shocked to pressures on the order of 10-35 GPa and were so shattered that their densities and seismic velocities now resemble those of sedimentary rocks. The morphology of the final crater, its structure as revealed in previous seismic imaging, and the results from the cores are completely consistent with modern numerical models of impact crater excavation and collapse that incorporate a model for post-impact weakening. Subsequent to the opening of a ca. 100 km diameter and 30 km deep transient crater, this enormous hole in the crust collapsed over a period of about 10 minutes. Collapse was enabled by movement of the underlying rocks, which briefly behaved in the manner of a high-viscosity fluid, a brittle
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Imaging the Buried Chicxulub Crater with Gravity Gradients and Cenotes
Hildebrand, A. R.; Pilkington, M.; Halpenny, J. F.; Ortiz-Aleman, C.; Chavez, R. E.; Urrutia-Fucugauchi, J.; Connors, M.; Graniel-Castro, E.; Camara-Zi, A.; Vasquez, J.
1995-09-01
Differing interpretations of the Bouguer gravity anomaly over the Chicxulub crater, Yucatan Peninsula, Mexico, have yielded diameter estimates of 170 to 320 km. Knowing the crater's size is necessary to quantify the lethal perturbations to the Cretaceous environment associated with its formation. The crater's size (and internal structure) is revealed by the horizontal gradient of the Bouguer gravity anomaly over the structure, and by mapping the karst features of the Yucatan region. To improve our resolution of the crater's gravity signature we collected additional gravity measurements primarily along radial profiles, but also to fill in previously unsurveyed areas. Horizontal gradient analysis of Bouguer gravity data objectively highlights the lateral density contrasts of the impact lithologies and suppresses regional anomalies which may obscure the gravity signature of the Chicxulub crater lithologies. This gradient technique yields a striking circular structure with at least 6 concentric gradient features between 25 and 85 km radius. These features are most distinct in the southwest probably because of denser sampling of the gravity field. Our detailed profiles detected an additional feature and steeper gradients (up to 5 mGal/km) than the original survey. We interpret the outer four gradient maxima to represent concentric faults in the crater's zone of slumping as is also revealed by seismic reflection data. The inner two probably represent the margin of the central uplift and the peak ring and or collapsed transient cavity. Radial gradients in the SW quadrant over the inferred ~40 km-diameter central uplift (4) may represent structural "puckering" as revealed at eroded terrestrial craters. Gradient features related to regional gravity highs and lows are visible outside the crater, but no concentric gradient features are apparent at distances > 90 km radius. The marginal gradient features may be modelled by slump faults as observed in large complex craters on
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APOLLO 17 PRELAUNCH ASTRONAUT TRAINING
1972-01-01
Apollo Command Module Pilot Evans, left, and Mission Commander Cernan, right, discuss their flight plans as each prepares to fly a T-38 jet aircraft at Patrick Air Force Base just south of the Spaceport. Astronauts Cernan and Evans flew the T-38 aircraft today on training flights over the Kennedy Space Center area to practice flying skills in preparation for upcoming launch to the Moon scheduled 12/06/72.
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Ceres' intriguing Occator crater and its faculae: formation and evolution
Buczkowski, D.; Scully, J. E. C.; Bowling, T.; Bu, C.; Castillo, J. C.; Jaumann, R.; Longobardo, A.; Nathues, A.; Neesemann, A.; Palomba, E.; Platz, T.; Quick, L. C.; Raponi, A.; Raymond, C. A.; Ruesch, O.; Russell, C. T.; Schenk, P.; Stein, N.
2017-12-01
Since March 2015, the Dawn spacecraft has orbited and explored Ceres, which is a dwarf planet and the largest object in the asteroid belt (radius 470 km). One of the most intriguing features on Ceres' surface is Occator crater, a 92-km-diameter impact crater that contains distinctive bright spots, called faculae, within its floor (Nathues et al., 2015; Russell et al., 2016; Schenk et al., 2017). Occator crater has been dated to 20-30 million years old (Nathues et al., 2017; Neesemann et al., 2017). The single scattering albedo of Occator's faculae is 0.67-0.80, which is greater than Ceres' average single scattering albedo of 0.09-0.11 (Li et al., 2016). The central facula is named Cerealia Facula, and is located in a 9 km wide and 700 m deep pit. There are also multiple additional faculae in the eastern crater floor, which are named the Vinalia Faculae. The faculae are mostly composed of sodium carbonate, are distinct from Ceres' average surface composition and are proposed to be the solid residues of crystallized brines (De Sanctis et al., 2016). The presence of such bright, apparently fresh, material on the surface of a dwarf planet that is billions of years old is intriguing, and indicates that active processes involving brines occurred within the geologically recent past. The Dawn Science Team has investigated whether the processes that formed the crater and the faculae are entirely endogenic, entirely exogenic or a combination of both. For example, the extensive lobate materials within the crater floor have been proposed to be impact melt, mass wasting deposits or cryolava flows (e.g. Buczkowski et al., 2017; Jaumann et al., 2017; Nathues et al., 2017; Schenk et al., 2017). Each possibility has the potential to provide fascinating insights into Ceres' evolution, including the potential for liquids within Ceres' interior today. The team's in-depth investigation of Occator crater will be presented in an upcoming special issue of the journal Icarus. This special
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Evolution of KREEP - Further petrologic evidence. [igneous rocks from Apollo 15 site
Crawford, M. L.; Hollister, L. S.
1977-01-01
It is hypothesized that KREEP samples from the Apollo 15 site are igneous. To support the hypothesis, comparisons are made with other crystalline KREEP samples, especially 14310. It is noted that the low siderophile element content and lack of high pressure phenocrysts in the Apollo 15 KREEP may be indications of a slower rise of KREEP melt to the surface, when contrasted with sample 14310. Gravitational separation of Fe-Ni metal is proposed as a mechanism to account for the depletion of siderophile elements relative to the Si-rich component. It is further suggested that KREEP may be the parent of Apollo 12 and 15 basalts, as well as of granitic rocks, due to the liquid immiscibility occurring during the KREEP melt crystallization, and the subsequent independent evolution of the components.
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Turbulent flow over craters on Mars: Vorticity dynamics reveal aeolian excavation mechanism
Anderson, William; Day, Mackenzie
2017-10-01
Impact craters are scattered across Mars. These craters exhibit geometric self-similarity over a spectrum of diameters, ranging from tens to thousands of kilometers. The late Noachian-early Hesperian boundary marks a dramatic shift in the role of mid-latitude craters, from depocenter sedimentary basins to aeolian source areas. At present day, many craters contain prominent layered sedimentary mounds with maximum elevations comparable to the rim height. The mounds are remnants of Noachian deposition and are surrounded by a radial moat. Large-eddy simulation has been used to model turbulent flows over synthetic craterlike geometries. Geometric attributes of the craters and the aloft flow have been carefully matched to resemble ambient conditions in the atmospheric boundary layer of Mars. Vorticity dynamics analysis within the crater basin reveals the presence of counterrotating helical vortices, verifying the efficacy of deflationary models put forth recently by Bennett and Bell [K. Bennett and J. Bell, Icarus 264, 331 (2016)], 10.1016/j.icarus.2015.09.041 and Day et al. [M. Day et al., Geophys. Res. Lett. 43, 2473 (2016)], 10.1002/2016GL068011. We show how these helical counterrotating vortices spiral around the outer rim, gradually deflating the moat and carving the mound; excavation occurs faster on the upwind side, explaining the radial eccentricity of the mounds relative to the surrounding crater basin.
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Turbulent flow over craters on Mars: Vorticity dynamics reveal aeolian excavation mechanism.
Anderson, William; Day, Mackenzie
2017-10-01
Impact craters are scattered across Mars. These craters exhibit geometric self-similarity over a spectrum of diameters, ranging from tens to thousands of kilometers. The late Noachian-early Hesperian boundary marks a dramatic shift in the role of mid-latitude craters, from depocenter sedimentary basins to aeolian source areas. At present day, many craters contain prominent layered sedimentary mounds with maximum elevations comparable to the rim height. The mounds are remnants of Noachian deposition and are surrounded by a radial moat. Large-eddy simulation has been used to model turbulent flows over synthetic craterlike geometries. Geometric attributes of the craters and the aloft flow have been carefully matched to resemble ambient conditions in the atmospheric boundary layer of Mars. Vorticity dynamics analysis within the crater basin reveals the presence of counterrotating helical vortices, verifying the efficacy of deflationary models put forth recently by Bennett and Bell [K. Bennett and J. Bell, Icarus 264, 331 (2016)]ICRSA50019-103510.1016/j.icarus.2015.09.041 and Day et al. [M. Day et al., Geophys. Res. Lett. 43, 2473 (2016)]GPRLAJ0094-827610.1002/2016GL068011. We show how these helical counterrotating vortices spiral around the outer rim, gradually deflating the moat and carving the mound; excavation occurs faster on the upwind side, explaining the radial eccentricity of the mounds relative to the surrounding crater basin.
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Crystal-Chemical Analysis Martian Minerals in Gale Crater
Morrison, S. M.; Downs, R. T.; Blake, D. F.; Bish, D. L.; Ming, D. W.; Morris, R. V.; Yen, A. S.; Chipera, S. J.; Treiman, A. H.; Vaniman, D. T.;
2015-01-01
The CheMin instrument on the Mars Science Laboratory rover Curiosity performed X-ray diffraction analyses on scooped soil at Rocknest and on drilled rock fines at Yellowknife Bay (John Klein and Cumberland samples), The Kimberley (Windjana sample), and Pahrump (Confidence Hills sample) in Gale crater, Mars. Samples were analyzed with the Rietveld method to determine the unit-cell parameters and abundance of each observed crystalline phase. Unit-cell parameters were used to estimate compositions of the major crystalline phases using crystal-chemical techniques. These phases include olivine, plagioclase and clinopyroxene minerals. Comparison of the CheMin sample unit-cell parameters with those in the literature provides an estimate of the chemical compositions of the major crystalline phases. Preliminary unit-cell parameters, abundances and compositions of crystalline phases found in Rocknest and Yellowknife Bay samples were reported in. Further instrument calibration, development of 2D-to- 1D pattern conversion corrections, and refinement of corrected data allows presentation of improved compositions for the above samples.
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Abraded Target on Rock 'Champagne' in Gusev Crater
2005-01-01
NASA's Mars Exploration Rover Spirit took this microscopic image of a target called 'Bubbles' on a rock called 'Champagne' after using its rock abrasion tool to grind a hole through the rock's outer surface. The circular area where the rock's interior is exposed is about 5 centimeters (2 inches) across. This rock is different from rocks out on the plains of Gusev Crater but is similar to other rocks in this area of the 'Columbia Hills' in that it rich in phosphorus. Plagioclase, a mineral commonly found in igneous rocks, is also present in these rocks, according to analysis with Spirit's miniature thermal emission spectrometer. By using the rover's alpha particle X-ray spectrometer to collect data for multiple martian days, or sols, scientists are also beginning to get measurements of trace elements in the rocks. Spirit took the images that are combined into this mosaic on sol 358 (Jan. 3, 2005).
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Wind-Eroded Crater Floors and Intercrater Plains, Terra Sabaea, Mars
Irwin, Rossman P.; Wray, James J.; Mest, Scott C.; Maxwell, Ted A.
2018-02-01
Ancient impact craters with wind-eroded layering on their floors provide a record of resurfacing materials and processes on early Mars. In a 54 km Noachian crater in Terra Sabaea (20.2°S, 42.6°E), eolian deflation of a friable, dark-toned layer up to tens of meters thick has exposed more resistant, underlying light-toned material. These layers differ significantly from strata of similar tone described in other regions of Mars. The light-toned material has no apparent internal stratification, and visible/near-infrared spectral analysis suggests that it is rich in feldspar. Its origin is ambiguous, as we cannot confidently reject igneous, pyroclastic, or clastic alternatives. The overlying dark-toned layer is probably a basaltic siltstone or sandstone that was emplaced mostly by wind, although its weak cementation and inverted fluvial paleochannels indicate some modification by water. Negative-relief channels are not found on the crater floor, and fluvial erosion is otherwise weakly expressed in the study area. Small impacts onto this crater's floor have exposed deeper friable materials that appear to contain goethite. Bedrock outcrops on the crater walls are phyllosilicate bearing. The intercrater plains contain remnants of a post-Noachian thin, widespread, likely eolian mantle with an indurated surface. Plains near Hellas-concentric escarpments to the north are more consistent with volcanic resurfacing. A 48 km crater nearby contains similar dark-over-light outcrops but no paleochannels. Our findings indicate that dark-over-light stratigraphy has diverse origins across Mars and that some dark-toned plains with mafic mineralogy are not of igneous origin.
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APOLLO 11 COMMANDER NEIL ARMSTRONG IN SIMULATOR
1969-01-01
Apollo 11 commander Neil Armstrong is going through flight training in the lunar module simulator situated in the flight crew training building at KSC. Armstrong will pilot the lunar module to a moon landing on July 20, following launch from KSC on July 16.
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International Nuclear Information System (INIS)
1970-01-01
On March 2 the Agency was host to the three Apollo-12 astronauts who placed the first atomic power generator on the moon. Accompanied by their wives, they were given a warm welcome and received mementos prepared by the Agency. In return they presented the Director General with a model of the SNAP-27 generator. (author)
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Fucugauchi, J. U.; Perez-Cruz, L. L.; Velasco-Villarreal, M.
2013-12-01
Drilling projects of impact structures provide data on the structure and stratigraphy of target, impact and post-impact lithologies, providing insight on the impact dynamics and cratering. Studies have successfully included magnetic well logging and analyses in core and cuttings, directed to characterize the subsurface stratigraphy and structure at depth. There are 170-180 impact craters documented in the terrestrial record, which is a small proportion compared to expectations derived from what is observed on the Moon, Mars and other bodies of the solar system. Knowledge of the internal 3-D deep structure of craters, critical for understanding impacts and crater formation, can best be studied by geophysics and drilling. On Earth, few craters have yet been investigated by drilling. Craters have been drilled as part of industry surveys and/or academic projects, including notably Chicxulub, Sudbury, Ries, Vredefort, Manson and many other craters. As part of the Continental ICDP program, drilling projects have been conducted on the Chicxulub, Bosumtwi, Chesapeake, Ries and El gygytgyn craters. Inclusion of continuous core recovery expanded the range of paleomagnetic and rock magnetic applications, with direct core laboratory measurements, which are part of the tools available in the ocean and continental drilling programs. Drilling studies are here briefly reviewed, with emphasis on the Chicxulub crater formed by an asteroid impact 66 Ma ago at the Cretaceous/Paleogene boundary. Chicxulub crater has no surface expression, covered by a kilometer of Cenozoic sediments, thus making drilling an essential tool. As part of our studies we have drilled eleven wells with continuous core recovery. Magnetic susceptibility logging, magnetostratigraphic, rock magnetic and fabric studies have been carried out and results used for lateral correlation, dating, formation evaluation, azimuthal core orientation and physical property contrasts. Contributions of magnetic studies on impact
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Technicians work with Apollo 14 lunar sample material in Lunar Receiving Lab.
1971-01-01
Glove handlers work with freshly opened Apollo 14 lunar sample material in modularized cabinets in the Lunar Receiving Laboratory at the Manned Spacecraft Center. The glove operator on the right starts to pour fine lunar material which he has just taken from a tote bag. This powdery sample was among the last to be revealed of the 90-odd pounds of material brought back to Earth by the Apollo 14 crewmen.
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Observations of an aeolian landscape: From surface to orbit in Gale Crater
Day, Mackenzie; Kocurek, Gary
2016-12-01
Landscapes derived solely from aeolian processes are rare on Earth because of the dominance of subaqueous processes. In contrast, aeolian-derived landscapes should typify Mars because of the absence of liquid water, the long exposure times of surfaces, and the presence of wind as the default geomorphic agent. Using the full range of available orbital and Mars Science Laboratory rover Curiosity images, wind-formed features in Gale Crater were cataloged and analyzed in order to characterize the aeolian landscape and to derive the evolution of the crater wind regime over time. Inferred wind directions show a dominance of regional northerly winds over geologic time-scales, but a dominance of topography-driven katabatic winds in modern times. Landscapes in Gale Crater show a preponderance of aeolian features at all spatial scales. Interpreted processes forming these features include first-cycle aeolian abrasion of bedrock, pervasive deflation, organization of available sand into bedforms, abundant cratering, and gravity-driven wasting, all of which occur over a background of slow physical weathering. The observed landscapes are proposed to represent a spectrum of progressive surface denudation from fractured bedrock, to retreating bedrock-capped mesas, to remnant hills capped by bedrock rubble, to desert pavement plains. This model of landscape evolution provides the mechanism by which northerly winds acting over ∼3 Ga excavated tens of thousands of cubic kilometers of material from the once sediment-filled crater, thus carving the intra-crater moat and exhuming Mount Sharp (Aeolis Mons). The current crater surface is relatively sand-starved, indicating that potential sediment deflation from the crater is greater than sediment production, and that most exhumation of Mount Sharp occurred in the ancient geologic past.
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International Nuclear Information System (INIS)
Woodruff, W.R.; Bryan, J.B.
1978-01-01
Single-charge and row-charge subsurface cratering experiments were performed to learn how close-spacing enhances single-crater dimensions. Our first experimental phase established cratering curves for 60-lb charges of the chemical explosive. For the second phase, to be described in a subsequent report, the Row-cratering experiments were designed and executed. This data report contains excavated dimensions and auxiliary data for the single-charge cratering experiments. The dimensions for the row-charge experiments will be in the other report. Significant changes in the soil's water content appeared to cause a variability in the excavated dimensions. This variability clouded the interpretation and application of the cratering curves obtained
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In plain sight: the Chesapeake Bay crater ejecta blanket
Griscom, D. L.
2012-02-01
The discovery nearly two decades ago of a 90 km-diameter impact crater below the lower Chesapeake Bay has gone unnoted by the general public because to date all published literature on the subject has described it as "buried". To the contrary, evidence is presented here that the so-called "upland deposits" that blanket ∼5000 km2 of the U.S. Middle-Atlantic Coastal Plain (M-ACP) display morphologic, lithologic, and stratigraphic features consistent with their being ejecta from the 35.4 Ma Chesapeake Bay Impact Structure (CBIS) and absolutely inconsistent with the prevailing belief that they are of fluvial origin. Specifically supporting impact origin are the facts that (i) a 95 %-pure iron ore endemic to the upland deposits of southern Maryland, eastern Virginia, and the District of Columbia has previously been proven to be impactoclastic in origin, (ii) this iron ore welds together a small percentage of well-rounded quartzite pebbles and cobbles of the upland deposits into brittle sheets interpretable as "spall plates" created in the interference-zone of the CBIS impact, (iii) the predominantly non-welded upland gravels have long ago been shown to be size sorted with an extreme crater-centric gradient far too large to have been the work of rivers, but well explained as atmospheric size-sorted interference-zone ejecta, (iv) new evidence is provided here that ~60 % of the non-welded quartzite pebbles and cobbles of the (lower lying) gravel member of the upland deposits display planar fractures attributable to interference-zone tensile waves, (v) the (overlying) loam member of the upland deposits is attributable to base-surge-type deposition, (vi) several exotic clasts found in a debris flow topographically below the upland deposits can only be explained as jetting-phase crater ejecta, and (vii) an allogenic granite boulder found among the upland deposits is deduced to have been launched into space and sculpted by hypervelocity air friction during reentry. An
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Mineralogical Diversity and Geology of Humboldt Crater Derived Using Moon Mineralogy Mapper Data
Martinot, M.; Besse, S.; Flahaut, J.; Quantin-Nataf, C.; Lozac'h, L.; van Westrenen, W.
2018-02-01
Moon Mineralogy Mapper (M3) spectroscopic data and high-resolution imagery data sets were used to study the mineralogy and geology of the 207 km diameter Humboldt crater. Analyses of M3 data, using a custom-made method for M3 spectra continuum removal and spectral parameters calculation, reveal multiple pure crystalline plagioclase detections within the Humboldt crater central peak complex, hinting at its crustal origin. However, olivine, spinel, and glass are observed in the crater walls and rims, suggesting these minerals derive from shallower levels than the plagioclase of the central peak complex. High-calcium pyroxenes are detected in association with volcanic deposits emplaced on the crater's floor. Geologic mapping was performed, and the age of Humboldt crater's units was estimated from crater counts. Results suggest that volcanic activity within this floor-fractured crater spanned over a billion years. The felsic mineralogy of the central peak complex region, which presumably excavated deeper material, and the shallow mafic minerals (olivine and spinel) detected in Humboldt crater walls and rim are not in accordance with the general view of the structure of the lunar crust. Our observations can be explained by the presence of a mafic pluton emplaced in the anorthositic crust prior to the Humboldt-forming impact event. Alternatively, the excavation of Australe basin ejecta could explain the observed mineralogical detections. This highlights the importance of detailed combined mineralogical and geological remote sensing studies to assess the heterogeneity of the lunar crust.
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Mineralogical Diversity and Geology of Humboldt Crater Derived Using Moon Mineralogy Mapper Data.
Martinot, M; Besse, S; Flahaut, J; Quantin-Nataf, C; Lozac'h, L; van Westrenen, W
2018-02-01
Moon Mineralogy Mapper (M 3 ) spectroscopic data and high-resolution imagery data sets were used to study the mineralogy and geology of the 207 km diameter Humboldt crater. Analyses of M 3 data, using a custom-made method for M 3 spectra continuum removal and spectral parameters calculation, reveal multiple pure crystalline plagioclase detections within the Humboldt crater central peak complex, hinting at its crustal origin. However, olivine, spinel, and glass are observed in the crater walls and rims, suggesting these minerals derive from shallower levels than the plagioclase of the central peak complex. High-calcium pyroxenes are detected in association with volcanic deposits emplaced on the crater's floor. Geologic mapping was performed, and the age of Humboldt crater's units was estimated from crater counts. Results suggest that volcanic activity within this floor-fractured crater spanned over a billion years. The felsic mineralogy of the central peak complex region, which presumably excavated deeper material, and the shallow mafic minerals (olivine and spinel) detected in Humboldt crater walls and rim are not in accordance with the general view of the structure of the lunar crust. Our observations can be explained by the presence of a mafic pluton emplaced in the anorthositic crust prior to the Humboldt-forming impact event. Alternatively, the excavation of Australe basin ejecta could explain the observed mineralogical detections. This highlights the importance of detailed combined mineralogical and geological remote sensing studies to assess the heterogeneity of the lunar crust.
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Testing models for the formation of the equatorial ridge on Iapetus via crater counting
Damptz, Amanda L.; Dombard, Andrew J.; Kirchoff, Michelle R.
2018-03-01
Iapetus's equatorial ridge, visible in global views of the moon, is unique in the Solar System. The formation of this feature is likely attributed to a key event in the evolution of Iapetus, and various models have been proposed as the source of the ridge. By surveying imagery from the Cassini and Voyager missions, this study aims to compile a database of the impact crater population on and around Iapetus's equatorial ridge, assess the relative age of the ridge from differences in cratering between on ridge and off ridge, and test the various models of ridge formation. This work presents a database that contains 7748 craters ranging from 0.83 km to 591 km in diameter. The database includes the study area in which the crater is located, the latitude and longitude of the crater, the major and minor axis lengths, and the azimuthal angle of orientation of the major axis. Analysis of crater orientation over the entire study area reveals that there is no preference for long-axis orientation, particularly in the area with the highest resolution. Comparison of the crater size-frequency distributions show that the crater distribution on the ridge appears to be depleted in craters larger than 16 km with an abruptly enhanced crater population less than 16 km in diameter up to saturation. One possible interpretation is that the ridge is a relatively younger surface with an enhanced small impactor population. Finally, the compiled results are used to examine each ridge formation hypothesis. Based on these results, a model of ridge formation via a tidally disrupted sub-satellite appears most consistent with our interpretation of a younger ridge with an enhanced small impactor population.
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Geologic Structures in Crater Walls on Vesta
Mittlefehldt, David W.; Beck, A. W.; Ammannito, E.; Carsenty, U.; DeSanctis, M. C.; LeCorre, L.; McCoy, T. J.; Reddy, V.; Schroeder, S. E.
2012-01-01
The Framing Camera (FC) on the Dawn spacecraft has imaged most of the illuminated surface of Vesta with a resolution of apporpx. 20 m/pixel through different wavelength filters that allow for identification of lithologic units. The Visible and Infrared Mapping Spectrometer (VIR) has imaged the surface at lower spatial resolution but high spectral resolution from 0.25 to 5 micron that allows for detailed mineralogical interpretation. The FC has imaged geologic structures in the walls of fresh craters and on scarps on the margin of the Rheasilvia basin that consist of cliff-forming, competent units, either as blocks or semi-continuous layers, hundreds of m to km below the rims. Different units have different albedos, FC color ratios and VIR spectral characteristics, and different units can be juxtaposed in individual craters. We will describe different examples of these competent units and present preliminary interpretations of the structures. A common occurrence is of blocks several hundred m in size of high albedo (bright) and low albedo (dark) materials protruding from crater walls. In many examples, dark material deposits lie below coherent bright material blocks. In FC Clementine color ratios, bright material is green indicating deeper 1 m pyroxene absorption band. VIR spectra show these to have deeper and wider 1 and 2 micron pyroxene absorption bands than the average vestan surface. The associated dark material has subdued pyroxene absorption features compared to the average vestan surface. Some dark material deposits are consistent with mixtures of HED materials with carbonaceous chondrites. This would indicate that some dark material deposits in crater walls are megabreccia blocks. The same would hold for bright material blocks found above them. Thus, these are not intact crustal units. Marcia crater is atypical in that the dark material forms a semi-continuous, thin layer immediately below bright material. Bright material occurs as one or more layers. In
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Underwater research methods for study of nuclear bomb craters, Enewetak, Marshall Islands
Shinn, E.A.; Halley, R.B.; Kindinger, J.L.; Hudson, J.H.; Slate, R.A.
1990-01-01
Three craters, created by the explosion of nuclear fusion devices, were mapped, sampled, core drilled and excavated with airlifts at Enewetak Atoll in the Marshall Islands by using scuba and a research submersible. The craters studied were Mike, Oak, and Koa. Tests took place near sea level at the transition between lithified reef flat and unlithified lagoonal sediments, where water depth ranged from 1 to 4 m. Craters produced by the blasts ranged from 30 to 60 m in depth. The purpose of our study was to determine crater diameter and depth immediately after detonation. Observations of submerged roadways and testing structures and upturned crater rims similar to those characteristic of meteor impacts indicate that the initial, or transient, craters were smaller than their present size. At some later time, while the area was too radioactive for direct examination, the sides of the craters slumped owing to dewatering of under lying pulverized rock. Core drilling of crater margins with a diver-operated hydraulic coring device provided additional data. On the seaward margin of the atoll, opposite Mike, a large portion of the atoll rim approximately the size of a city block had slumped into the deep ocean, leaving a clean vertical rock section more than 400m high. An abundance of aggressive grey reef sharks displaying classic territorial behavior prevented use of scuba at the Mike slump site. The two-person submersible R.V. Delta provided protection and allowed observations down to 300 m. During the 6-week period of study, we made more than 300 scuba and 275 submersible dives. Mapping was with side scan sonar and continuous video sweeps supplemented by tape-recorded verbal descriptions made from within the submersible. A mini-ranger navigation system linked to the submersible allowed plotting of bottom features, depth and sediment type with spatial accuracy to within 2 m.
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Apollo 15 mare volcanism: constraints and problems
International Nuclear Information System (INIS)
Delano, J.W.
1985-01-01
The Apollo 15 landing site contains more volcanics in the form of crystalline basalts and pristine glasses, which form the framework for all models dealing with the mantle beneath that site. Major issues on the petrology of the mare source regions beneath that portion of Mare Imbrium are summarized
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Remembering the Giants: Apollo Rocket Propulsion Development
Fisher, Steven C. (Editor); Rahman, Shamim A. (Editor)
2009-01-01
Topics discussed include: Rocketdyne - F-1 Saturn V First Stage Engine; Rocketdyne - J-2 Saturn V 2nd & 3rd Stage Engine; Rocketdyne - SE-7 & SE-8 Engines; Aerojet - AJ10-137 Apollo Service Module Engine; Aerojet - Attitude Control Engines; TRW - Lunar Descent Engine; and Rocketdyne - Lunar Ascent Engine.
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Crater size-frequency distributions and a revised Martian relative chronology
International Nuclear Information System (INIS)
Barlow, N.G.
1988-01-01
A relative plotting technique is applied to Viking 1:2M photomosaics of 25,826 Martian craters of diameter greater than 8 km and age younger than that of the Martian surface. The size-frequency distribution curves are calculated and analyzed in detail, and the results are presented in extensive tables and maps. It is found that about 60 percent of the crater-containing lithologic units, including many small volcanoes and the ridged planes, were formed during the heavy-bombardment period (HBP), while 40 percent arose after the HBP. Wide region-to-region variation in the crater density is noted, and localized age estimates are provided. 42 references
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A model for calculating expected performance of the Apollo unified S-band (USB) communication system
Schroeder, N. W.
1971-01-01
A model for calculating the expected performance of the Apollo unified S-band (USB) communication system is presented. The general organization of the Apollo USB is described. The mathematical model is reviewed and the computer program for implementation of the calculations is included.
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APOLLO-2: An advanced transport code for LWRs
International Nuclear Information System (INIS)
Mathonniere, G.
1995-01-01
APOLLO-2 is a fully modular code in which each module corresponds to a specific task: access to the cross-sections libraries, creation of isotopes medium or mixtures, geometry definition, self-shielding calculations, computation of multigroup collision probabilities, flux solver, depletion calculations, transport-transport or transport-diffusion equivalence process, SN calculations, etc... Modules communicate exclusively by ''objects'' containing structured data, these objects are identified and handled by user's given names. Among the major improvements offered by APOLLO-2 the modelization of the self-shielding: it is possible now to deal with a great precision, checked versus Montecarlo calculations, a fuel rod divided into several concentric rings. So the total production of Plutonium is quite better estimated than before and its radial distribution may be predicted also with a good accuracy. Thanks to the versatility of the code some reference calculations and routine ones may be compared easily because only one parameter is changed; for example the self-shielding approximations are modified, the libraries or the flux solver being exactly the same. Other interesting features have been introduced in APOLLO-2: the new isotopes JEF.2 are available in 99 and 172 energy groups libraries, the surface leakage model improves the calculation of the control rod efficiency, the flux-current method allows faster calculations, the possibility of an automatic convergence checking during the depletion calculations coupled with fully automatic corrections, heterogeneous diffusion coefficients used for voiding analysis. 17 refs, 1 tab
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Proceedings of the Geophysical Laboratory/Lawrence Radiation Laboratory Cratering Symposium
Energy Technology Data Exchange (ETDEWEB)
Nordyke, Milo D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
1961-10-01
The geological papers in this morning's session will deal descriptively with surficial features and end products of impact craters caused by meteorite falls. Such items as breccia, structural deformation, normal and inverse stratigraphy, glass (fused rock), and coesite will frequently be mentioned. Meteor and explosion crater data are presented.
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Parameters critical to the morphology of fluidization craters
Siegal, B. S.; Gold, D. P.
1973-01-01
In order to study further the role of fluidization on the moon, a laboratory investigation was undertaken on two particulate material size fractions to determine the effect of variables, such as, duration of gas streaming, gas pressure, and 'regolith' thickness on the morphology of fluidization craters. A 3.175-mm cylindrical vent was used to simulate a gas streaming conduit. Details of the fluidization chamber are discussed together with questions of experimental control, aspects of nomenclature, crater measurements, and the effect of variables.
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Remote Sensing Observations and Numerical Simulation for Martian Layered Ejecta Craters
Li, L.; Yue, Z.; Zhang, C.; Li, D.
2018-04-01
To understand past Martian climates, it is important to know the distribution and nature of water ice on Mars. Impact craters are widely used ubiquitous indicators for the presence of subsurface water or ice on Mars. Remote sensing observations and numerical simulation are powerful tools for investigating morphological and topographic features on planetary surfaces, and we can use the morphology of layered ejecta craters and hydrocode modeling to constrain possible layering and impact environments. The approach of this work consists of three stages. Firstly, the morphological characteristics of the Martian layered ejecta craters are performed based on Martian images and DEM data. Secondly, numerical modeling layered ejecta are performed through the hydrocode iSALE (impact-SALE). We present hydrocode modeling of impacts onto targets with a single icy layer within an otherwise uniform basalt crust to quantify the effects of subsurface H2O on observable layered ejecta morphologies. The model setup is based on a layered target made up of a regolithic layer (described by the basalt ANEOS), on top an ice layer (described by ANEOS equation of H2O ice), in turn on top of an underlying basaltic crust. The bolide is a 0.8 km diameter basaltic asteroid hitting the Martian surface vertically at a velocity of 12.8 km/s. Finally, the numerical results are compared with the MOLA DEM profile in order to analyze the formation mechanism of Martian layered ejecta craters. Our simulations suggest that the presence of an icy layer significantly modifies the cratering mechanics, and many of the unusual features of SLE craters may be explained by the presence of icy layers. Impact cratering on icy satellites is significantly affected by the presence of subsurface H2O.
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Image processing and data reduction of Apollo low light level photographs
Alvord, G. C.
1975-01-01
The removal of the lens induced vignetting from a selected sample of the Apollo low light level photographs is discussed. The methods used were developed earlier. A study of the effect of noise on vignetting removal and the comparability of the Apollo 35mm Nikon lens vignetting was also undertaken. The vignetting removal was successful to about 10% photometry, and noise has a severe effect on the useful photometric output data. Separate vignetting functions must be used for different flights since the vignetting function varies from camera to camera in size and shape.
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Apollo 16 time and motion study
Kubis, J. F.; Elrod, J. T.; Rusnak, R.; Barnes, J. E.; Saxon, S. C.
1972-01-01
A time and motion study is presented of astronaut lunar surface activity on Apollo 16 which consists of five distinct analyses: an evaluation of lunar mobility, a comparison of task performance in 1-g training and lunar EVA, a study of metabolic costs and adaptation, a discussion of falls, and retrieval of fallen objects. Two basic mobility patterns, the hop or canter and the traditional walking gait, were consistently utilized in longer traverses. The metabolic rates associated with these two mobility types, each used by a different astronaut, were relatively equivalent. The time to perform tasks on the lunar surface was significantly longer (on the order of 70%) than the time to perform the same tasks during the last 1-g training session. These results corroborated the findings on Apollo 15 and were not significantly different from them. There was general improvement in lunar EVA performance upon repetition of tasks. Metabolic rate (BTU/hr.) and metabolic cost (BTU) decreased over successive EVAs. Specifically, the metabolic rate associated with riding the lunar roving vehicle (LRV) decreased by approximately 18% from EVA 1 to EVA 2 and by 15% from EVA 2 to EVA 3.
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Hadley Rille, lava tubes and mare volcanism at the Apollo 15 site
International Nuclear Information System (INIS)
Greeley, R.; Spudis, P.D.
1985-01-01
Hadley Rille appears to be a collapsed lava tube/channel, whose formation history may be more intimately related to the mare units sampled at 15 than was previously thought. More work is needed relating samples and observations from Apollo 15 to the rille and its geologic evolution. As the only sinuous rille visited during the Apollo missions, Hadley Rille represents a data source that is directly applicable to the deciphering of processes involved in lunar mare volcanism
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Murr, L. E.; Rivas, J. M.; Quinones, S.; Niou, C.-S.; Advani, A. H.; Marquez, B.
1993-01-01
Debris particles extracted from a small sampling region on the leading edge of the Long Duration Exposure Facility (LDEF) spacecraft have been examined by analytical transmission electron microscopy and the elemental frequency observed by energy-dispersive X-ray spectrometry and compared with upper atmosphere (Earth) particle elemental frequency and the average elemental compositions of interplanetary dust particles. A much broader elemental distribution was observed for the exposed spacecraft surface debris milieu. Numerous metal microfragment analyses, particularly aluminum and stainless steel, were compared with scanning electron microscope observations-of impact crater features, and the corresponding elemental spectra on selected LDEF aluminium tray clamps and stainless steel bolts. The compositions and melt features for these impact craters and ejecta have been shown to be consistent with microcrystalline debris fragments in the case of aluminum, and these observations suggest an ever changing debris milieu on exposed surfaces for space craft and space system materials.
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Restoration of APOLLO Data by the NSSDC and PDS Lunar Data Node
Williams, David R.; Hills, H. Kent; Guinness, Edward A.; Taylor, Patrick T.; McBride, Marie J.
2012-01-01
The Apollo Lunar Surface Experiment Packages (ALSEPs), suites of instruments deployed by the Apollo 12. 14, 15, 16 and 17 astronauts on the lunar surface, still represent the only in-situ measurements of the Moon's environment taken over long time periods, Much of these data are housed at the National Space Science Data Center (NSSDC) at Goddard Space Flight Center but are in forms that are not readily usable, such as microfilm, hardcopy, and magnetic tapes with older, obsolete formats. The Lunar Data Node (LDN) has been formed under the auspices of the Planetary Data System (PDS) Geosciences Node to put relevant, scientifically important Apollo data into accessible digital form for use by researchers and mission planners. The LDN has prioritized the restoration of these data based on their scientific and engineering value and the level of effort required. We will report on progress made and plans for future data restorations.
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Impact ejecta and carbonate sequence in the eastern sector of the Chicxulub crater
Urrutia-Fucugauchi, Jaime; Chavez-Aguirre, Jose Maria; Pérez-Cruz, Ligia; De la Rosa, Jose Luis
2008-12-01
The Chicxulub 200 km diameter crater located in the Yucatan platform of the Gulf of Mexico formed 65 Myr ago and has since been covered by Tertiary post-impact carbonates. The sediment cover and absence of significant volcanic and tectonic activity in the carbonate platform have protected the crater from erosion and deformation, making Chicxulub the only large multi-ring crater in which ejecta is well preserved. Ejecta deposits have been studied by drilling/coring in the southern crater sector and at outcrops in Belize, Quintana Roo and Campeche; little information is available from other sectors. Here, we report on the drilling/coring of a section of ˜34 m of carbonate breccias at 250 m depth in the Valladolid area (120 km away from crater center), which are interpreted as Chicxulub proximal ejecta deposits. The Valladolid breccias correlate with the carbonate breccias cored in the Peto and Tekax boreholes to the south and at similar radial distance. This constitutes the first report of breccias in the eastern sector close to the crater rim. Thickness of the Valladolid breccias is less than that at the other sites, which may indicate erosion of the ejecta deposits before reestablishment of carbonate deposition. The region east of the crater rim appears different from regions to the south and west, characterized by high density and scattered distribution of sinkholes.
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Tang, Jiajing; Yang, Xiaodong
2017-09-01
A novel thermo-hydraulic coupling model was proposed in this study to investigate the crater formation in electrical discharge machining (EDM). The temperature distribution of workpiece materials was included, and the crater formation process was explained from the perspective of hydrodynamic characteristics of the molten region. To better track the morphology of the crater and the movement of debris, the level-set method was introduced in this study. Simulation results showed that the crater appears shortly after the ignition of the discharge, and the molten material is removed by vaporizing in the initial stage, then by splashing at the following time. The driving force for the detachment of debris in the splashing removal stage comes from the extremely large pressure difference in the upper part of the molten region, and the morphology of the crater is also influenced by the shearing flow of molten material. It was found that the removal ratio of molten material is only about 7.63% under the studied conditions, leaving most to form the re-solidification layer on the surface of the crater. The size of the crater reaches the maximum at the end of discharge duration then experiences a slight reduction because of the reflux of molten material after the discharge. The results of single pulse discharge experiments showed that the morphologies and sizes between the simulation crater and actual crater are good at agreement, verifying the feasibility of the proposed thermo-hydraulic coupling model in explaining the mechanisms of crater formation in EDM.
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The isostatic state of Mead crater
Banerdt, W. B.; Konopliv, A. S.; Rappaport, N. J.; Sjogren, W. L.; Grimm, R. E.; Ford, P. G.
1994-01-01
We have analyzed high-resolution Magellan Doppler tracking data over Mead crater, using both line-of-sight and spherical harmonic methods, and have found a negative gravity anomaly of about 4-5 mgal (at spacecraft altitude, 182 km). This is consistent with no isostatic compensation of the present topography; the uncertainty in the analysis allows perhaps as much as 30% compensation at shallow dpeths (approximately 25 km). This is similar to observations of large craters on Earth, which are not generally compensated, but contrasts with at least some lunar basins which are inferred to have large Moho uplifts and corresponding positive Bouguer anomalies. An uncompensated load of this size requires a lithosphere with an effective elastic lithosphere thickness greater than 30 km. In order for the crust-mantle boundary not to have participated in the deformation associated with the collapse of the transient cavity during the creation of the crater, the yield strength near the top of the mantle must have been significantly higher on Earth and Venus than on the Moon at the time of basin formation. This might be due to increased strength against frictional sliding at the higher confining pressures within the larger planets. Alternatively, the thinner crusts of Earth and Venus compared to that of the Moon may result in higher creep strength of the upper mantle at shallower depths.
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Crater formation by single ions, cluster ions and ion "showers"
Djurabekova, Flyura; Timko, Helga; Nordlund, Kai; Calatroni, Sergio; Taborelli, Mauro; Wuensch, Walter
2011-01-01
The various craters formed by giant objects, macroscopic collisions and nanoscale impacts exhibit an intriguing resemblance in shapes. At the same time, the arc plasma built up in the presence of sufficiently high electric fields at close look causes very similar damage on the surfaces. Although the plasma–wall interaction is far from a single heavy ion impact over dense metal surfaces or the one of a cluster ion, the craters seen on metal surfaces after a plasma discharge make it possible to link this event to the known mechanisms of the crater formations. During the plasma discharge in a high electric field the surface is subject to high fluxes (~1025 cm-2s-1) of ions with roughly equal energies typically of the order of a few keV. To simulate such a process it is possible to use a cloud of ions of the same energy. In the present work we follow the effect of such a flux of ions impinging the surface in the ‘‘shower’’ manner, to find the transition between the different mechanisms of crater formati...
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Jozwiak, L. M.; Head, J. W., III; Neumann, G. A.; Wilson, L.
2016-01-01
Floor-fractured craters are a class of lunar crater hypothesized to form in response to the emplacement of a shallow magmatic intrusion beneath the crater floor. The emplacement of a shallow magmatic body should result in a positive Bouguer anomaly relative to unaltered complex craters, a signal which is observed for the average Bouguer anomaly interior to the crater walls. We observe the Bouguer anomaly of floor-fractured craters on an individual basis using the unfiltered Bouguer gravity solution from GRAIL and also a degree 100-600 band-filtered Bouguer gravity solution. The low-magnitude of anomalies arising from shallow magmatic intrusions makes identification using unfiltered Bouguer gravity solutions inconclusive. The observed anomalies in the degree 100-600 Bouguer gravity solution are spatially heterogeneous, although there is spatial correlation between volcanic surface morphologies and positive Bouguer anomalies. We interpret these observations to mean that the spatial heterogeneity observed in the Bouguer signal is the result of variable degrees of magmatic degassing within the intrusions.
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Deposition, exhumation, and paleoclimate of an ancient lake deposit, Gale crater, Mars
Grotzinger, JP; Gupta, S; Malin, MC; Rubin, DM; Schieber, J; Siebach, K; Sumner, DY; Stack, KM; Vasavada, AR; Arvidson, RE; Calef, F; Edgar, L; Fischer, WF; Grant, JA; Griffes, J
2015-01-01
The landforms of northern Gale crater on Mars expose thick sequences of sedimentary rocks. Based on images obtained by the Curiosity rover, we interpret these outcrops as evidence for past fluvial, deltaic, and lacustrine environments. Degradation of the crater wall and rim probably supplied these sediments, which advanced inward from the wall, infilling both the crater and an internal lake basin to a thickness of at least 75 meters. This intracrater lake system probably existed intermittentl...
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Code-Name: Spider, Flight of Apollo 9.
National Aeronautics and Space Administration, Washington, DC.
Apollo 9, an earth orbiting mission during which the Lunar Module was first tested in space flight in preparation for the eventual moon landing missions, is the subject of this pamphlet. Many color photographs and diagrams of the Lunar Module and flight activities are included with a brief description of the mission. (PR)
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Countdown to a Moon launch preparing Apollo for its historic journey
Ward, Jonathan H
2015-01-01
Thousands of workers labored at Kennedy Space Center around the clock, seven days a week, for half a year to prepare a mission for the liftoff of Apollo 11. This is the story of what went on during those hectic six months. Countdown to a Moon Launch provides an in-depth look at the carefully choreographed workflow for an Apollo mission at KSC. Using the Apollo 11 mission as an example, readers will learn what went on day by day to transform partially completed stages and crates of parts into a ready-to-fly Saturn V. Firsthand accounts of launch pad accidents, near misses, suspected sabotage, and last-minute changes to hardware are told by more than 70 NASA employees and its contractors. A companion to Rocket Ranch, it includes many diagrams and photographs, some never before published, to illustrate all aspects of the process. NASA’s groundbreaking use of computers for testing and advanced management techniques are also covered in detail. This book will demystify the question of how NASA could build and lau...
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Apollo 11 Astronaut Armstrong Arrives at the Flight Crew Training Building
1969-01-01
In this photograph, Apollo 11 astronaut Neil Armstrong walks to the flight crew training building at the NASA Kennedy Space Center (KSC) in Florida, one week before the nation's first lunar landing mission. The Apollo 11 mission launched from KSC via the Marshall Space Flight Center (MSFC) developed Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. Aboard the space craft were astronauts Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. (Buzz) Aldrin Jr., Lunar Module (LM) pilot. The CM, 'Columbia', piloted by Collins, remained in a parking orbit around the Moon while the LM, 'Eagle'', carrying astronauts Armstrong and Aldrin, landed on the Moon. On July 20, 1969, Armstrong was the first human to ever stand on the lunar surface, followed by Aldrin. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. With the success of Apollo 11, the national objective to land men on the Moon and return them safely to Earth had been accomplished.
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Scaling of cratering experiments: an analytical and heuristic approach to the phenomenology
International Nuclear Information System (INIS)
Killian, B.G.; Germain, L.S.
1977-01-01
The phenomenology of cratering can be thought of as consisting of two phases. The first phase, where the effects of gravity are negligible, consists of the energy source dynamically imparting its energy to the surroundings, rock and air. As illustrated in this paper, the first phase can be scaled if: radiation effects are negligible, experiments are conducted in the same rock material, time and distance use the same scaling factor, and distances scale as the cube root of the energy. The second phase of cratering consists of the rock, with its already developed velocity field, being thrown out. It is governed by the ballistics equation, and gravity is of primary importance. This second phase of cratering is examined heuristically by examples of the ballistics equation which illustrate the basic phenomena in crater formation. When gravity becomes significant, in addition to the conditions for scaling imposed in the first phase, distances must scale inversely as the ratio of gravities. A qualitative relationship for crater radius is derived and compared with calculations and experimental data over a wide range of energy sources and gravities
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Apollo 11 crew on ship during water egress training in Gulf of Mexico
1969-01-01
The prime crew of the Apollo 11 lunar landing mission relaxes on the deck of the NASA Motor Vessel Retriever prior to participating in water egress training in the Gulf of Mexico. Left to right, are Astronauts Edwin A. Aldrin Jr., lunar module pilot; Neil A. Armstrong, commander; and Michael Collins, command module pilot. In the background is Apollo Boilerplate 1102 which was used in the training exercise.
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Origin of the outer layer of martian low-aspect ratio layered ejecta craters
Boyce, Joseph M.; Wilson, Lionel; Barlow, Nadine G.
2015-01-01
Low-aspect ratio layered ejecta (LARLE) craters are one of the most enigmatic types of martian layered ejecta craters. We propose that the extensive outer layer of these craters is produced through the same base surge mechanism as that which produced the base surge deposits generated by near-surface, buried nuclear and high-explosive detonations. However, the LARLE layers have higher aspect ratios compared with base surge deposits from explosion craters, a result of differences in thicknesses of these layers. This characteristics is probably caused by the addition of large amounts of small particles of dust and ice derived from climate-related mantles of snow, ice and dust in the areas where LARLE craters form. These deposits are likely to be quickly stabilized (order of a few days to a few years) from eolian erosion by formation of duricrust produced by diffusion of water vapor out of the deposits.
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Was Project Management Life Really Better in Apollo?
2010-01-01
This slide presentation discusses the question of "Was Project Management Life Really Better in Apollo?" Was money really flowing freely all through Apollo? Are we wallowing in nostalgia and comparing current circumstances to a managerial time which did not exist? This talk discusses these and other questions as background for you as today s project managers. There are slides showing the timelines from before the speech that Kennedy gave promising to land a man on the moon, to the early 60's, when the manned space center prepared the preliminary lunar landing mission design, an NASA organization chart from 1970, various photos of the rockets, and the astronauts are presented. The next slides discuss the budgets from the 1960's to the early 1970's. Also the results of a survey of 62 managers, who were asked "What problems pose the greatest obstacles to successful project performance?"
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Odysseus and the Cult of Apollo at Delos
Directory of Open Access Journals (Sweden)
Jim Marks
2016-03-01
Full Text Available This paper explores literary representations of the cult of Apollo on Delos. This island is, to be sure, mentioned only occasionally in early Greek poetry, but details specific to the cult do appear. Thus, for example, Odysseus describes a palm tree he saw at an altar of Apollo on Delos (Od. 6.162-3, and a third-century inscription from the island mentions just such a feature. References to a palm, altar, and temple at Delos in later classical authors, including Callimachus, Pliny, Cicero, and Plutarch, demonstrate that the Archaic period traditions represented by the Homeric passages continued to shape how successive generations of visitors understood Delos. The material record makes clear that the Greek epic tradition documents a time when Delos was already a well attended sanctuary, and that later constructions at the site attempted to remain consistent with the details preserved in the epics.
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A crater and its ejecta: An interpretation of Deep Impact
Holsapple, Keith A.; Housen, Kevin R.
2007-03-01
We apply recently updated scaling laws for impact cratering and ejecta to interpret observations of the Deep Impact event. An important question is whether the cratering event was gravity or strength-dominated; the answer gives important clues about the properties of the surface material of Tempel 1. Gravity scaling was assumed in pre-event calculations and has been asserted in initial studies of the mission results. Because the gravity field of Tempel 1 is extremely weak, a gravity-dominated event necessarily implies a surface with essentially zero strength. The conclusion of gravity scaling was based mainly on the interpretation that the impact ejecta plume remained attached to the comet during its evolution. We address that feature here, and conclude that even strength-dominated craters would result in a plume that appeared to remain attached to the surface. We then calculate the plume characteristics from scaling laws for a variety of material types, and for gravity and strength-dominated cases. We find that no model of cratering alone can match the reported observation of plume mass and brightness history. Instead, comet-like acceleration mechanisms such as expanding vapor clouds are required to move the ejected mass to the far field in a few-hour time frame. With such mechanisms, and to within the large uncertainties, either gravity or strength craters can provide the levels of estimated observed mass. Thus, the observations are unlikely to answer the questions about the mechanical nature of the Tempel 1 surface.
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Łukasiewicz, Kinga; Sanak, Marek; Węgrzyn, Grzegorz
2016-02-01
Parnassius apollo (Lepidoptera: Papilionidae) is a butterfly species which was common in Europe in 19th century, but now it is considered as near threatened. Various programs devoted to protect and save P. apollo have been established, between others the one in Pieniny National Park (Poland). An isolated population of this butterfly has been restored there from a small group of 20-30 individuals in early 1990s. However, deformations or reductions of wings occur in this population in a relatively large number of insects, and the cause of this phenomenon is not known. In this report, the occurrence of lesions in the wingless (wg) gene is demonstrated in most of tested butterflies with deformed or reduced wings, but not in normal insects. Although the analyses indicated that wg lesion(s) cannot be the sole cause of the deformed or reduced wings in the population of P. apollo from Pieniny, the discovery that this genetic defect occurs in most of malformed individuals, can be considered as an important step in understanding this phenomenon. Copyright © 2015 Elsevier B.V. All rights reserved.
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Farrand, W. H.; Johnson, J. R.; Bell, J. F., III; Mittlefehldt, D.W.
2016-01-01
The Mars Exploration Rover Opportunity has been exploring the western rim of the 22 km diameter Endeavour crater since August, 2011. Recently, Opportunity has reached a break in the Endeavour rim that the rover team has named Mara-thon Valley. This is the site where orbital observations from the MRO CRISM imaging spectrometer indicated the presence of iron smectites. On the outer western portion of Marathon Valley, Opportunity explored the crater-form feature dubbed Spirit of St. Louis (SoSL) crater. This presentation describes the 430 to 1009 nm (VNIR) reflectance, measured by the rover's Pancam, of rock units present both at Spirit of St. Louis and within Marathon Valley.
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Benchmark calculation of APOLLO-2 and SLAROM-UF in a fast reactor lattice
International Nuclear Information System (INIS)
Hazama, T.
2009-07-01
A lattice cell benchmark calculation is carried out for APOLLO2 and SLAROM-UF on the infinite lattice of a simple pin cell featuring a fast reactor. The accuracy in k-infinity and reaction rates is investigated in their reference and standard level calculations. In the 1. reference level calculation, APOLLO2 and SLAROM-UF agree with the reference value of k-infinity obtained by a continuous energy Monte Carlo calculation within 50 pcm. However, larger errors are observed in a particular reaction rate and energy range. The major problem common to both codes is in the cross section library of 239 Pu in the unresolved energy range. In the 2. reference level calculation, which is based on the ECCO 1968 group structure, both results of k-infinity agree with the reference value within 100 pcm. The resonance overlap effect is observed by several percents in cross sections of heavy nuclides. In the standard level calculation based on the APOLLO2 library creation methodology, a discrepancy appears by more than 300 pcm. A restriction is revealed in APOLLO2. Its standard cross section library does not have a sufficiently small background cross section to evaluate the self shielding effect on 56 Fe cross sections. The restriction can be removed by introducing the mixture self-shielding treatment recently introduced to APOLLO2. SLAROM-UF original standard level calculation based on the JFS-3 library creation methodology is the best among the standard level calculations. Improvement from the SLAROM-UF standard level calculation is achieved mainly by use of a proper weight function for light or intermediate nuclides. (author)
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Geology of McLaughlin Crater, Mars: A Unique Lacustrine Setting with Implications for Astrobiology
Michalski, J. R.; Niles, P. B.; Rogers, A. D.; Johnson, S. S.; Ashley, J. W.; Golombek, M. P.
2016-01-01
McLaughlin crater is a 92-kmdiameter Martian impact crater that contained an ancient carbonate- and clay mineral-bearing lake in the Late Noachian. Detailed analysis of the geology within this crater reveals a complex history with important implications for astrobiology [1]. The basin contains evidence for, among other deposits, hydrothermally altered rocks, delta deposits, deep water (>400 m) sediments, and potentially turbidites. The geology of this basin stands in stark contrast to that of some ancient basins that contain evidence for transient aqueous processes and airfall sediments (e.g. Gale Crater [2-3]).
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Kereszturi, Akos; Steinmann, Vilmos
2017-11-01
Analysing the size-frequency distribution of very small lunar craters (sized below 100 m including ones below 10 m) using LROC images, spatial density and related age estimations were calculated for mare and terra terrains. Altogether 1.55 km2 area was surveyed composed of 0.1-0.2 km2 units, counting 2784 craters. The maximal areal density was present at the 4-8 m diameter range at every analysed terrain suggesting the bombardment is areally relatively homogeneous. Analysing the similarities and differences between various areas, the mare terrains look about two times older than the terra terrains using ages ranged between 13 and 20 Ma for mare, 4-6 Ma for terra terrains. Substantial fluctuation (min: 936 craters/km2, max: 2495 craters/km2) was observed without obvious source of nearby secondaries or fresh ejecta blanket produced fresh crater. Randomness analysis and visual inspection also suggested no secondary craters or ejecta blanket from fresh impact could contribute substantially in the observed heterogeneity of the areal distribution of small craters - thus distant secondaries or even other, poorly known resurfacing processes should be considered in the future. The difference between the terra/mare ages might come only partly from the easier identification of small craters on smooth mare terrains, as the differences were observed for larger (30-60 m diameter) craters too. Difference in the target hardness could more contribute in this effect. It was possible to separate two groups of small craters based on their appearance: a rimmed thus less eroded, and a rimless thus more eroded one. As the separate usage of different morphology groups of craters for age estimation at the same area is not justifiable, this was used only for comparison. The SFD curves of these two groups showed characteristic differences: the steepness of the fresh craters' SFD curves are similar to each other and were larger than the isochrones. The eroded craters' SFD curves also resemble
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Parker, T. J.; Pieri, D. C.
1985-01-01
Flow ejecta craters - craters surrounded by lobate ejecta blankets - are found throughout the study area. The ratio of the crater's diameter to that of the flow ejecta in this region is approximately 40 to 45%. Flow ejecta craters are dominantly sharply defined craters, with slightly degraded craters being somewhat less common. This is probably indicative of the ejecta's relatively low resistence to weathering and susceptibility to burial. Flow ejecta craters here seem to occur within a narrow range of crater sizes - the smallest being about 4km in diameter and the largest being about 27km in diameter. Ejecta blankets of craters at 4km are easily seen and those of smaller craters are simply not seen even in images with better than average resolution for the region. This may be due to the depth of excavation of small impacting bodies being insufficient to reach volatile-rich material. Flow ejecta craters above 24km are rare, and those craters above 27km do not display flow ejecta blankets. This may be a result of an excavation depth so great that the volatile content of the ejecta is insufficient to form a fluid ejecta blanket. The geomorphic/geologic unit appears also to play an important role in the formation of flow ejecta craters. Given the typical size range for the occurrence of flow ejecta craters for most units, it can be seen that the percentage of flow ejecta craters to the total number of craters within this size range varies significantly from one unit to the next. The wide variance in flow ejecta crater density over this relatively small geographical area argues strongly for a lithologic control of their distribution.
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Chemical differences between small subsamples of Apollo 15 olivine-normative basalts
Shervais, J. W.; Vetter, S. K.; Lindstrom, M. M.
1990-01-01
Results are presented on the chemical and petrological characterization of nine samples of an Apollo 15 mare basalt suite. The results show that all nine samples are low-silica olivine normative basalts (ONBs) similar to those described earlier for low-silica ONBs from Apollo 15 site. The samples were found to vary in texture and grain size, from fine-grained intergranular or subophitic basalts to coarse-grained granular 'microgabbros'. Several displayed macroscopic heterogeneity. Variation diagrams show that the overall trend of the data is consistent with the fractionation of olivine (plus minor Cr-spinel) from a high-MgO parent magma.
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Automated Detection of Craters in Martian Satellite Imagery Using Convolutional Neural Networks
Norman, C. J.; Paxman, J.; Benedix, G. K.; Tan, T.; Bland, P. A.; Towner, M.
2018-04-01
Crater counting is used in determining surface age of planets. We propose improvements to martian Crater Detection Algorithms by implementing an end-to-end detection approach with the possibility of scaling the algorithm planet-wide.
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Flat plate film cooling at the coolant supply into triangular and cylindrical craters
Directory of Open Access Journals (Sweden)
Khalatov Artem A.
2017-01-01
Full Text Available The results are given of the film cooling numerical simulation of three different schemes including single-array of the traditional round inclined holes, as well as inclined holes arranged in the cylindrical or triangular dimples (craters. The results of simulation showed that at the medium and high values of the blowing ratio (m > 1.0 the scheme with coolant supply into triangular craters improves the adiabatic film cooling efficiency by 1.5…2.7 times compared to the traditional array of inclined holes, or by 1.3…1.8 times compared to the scheme with coolant supply into cylindrical craters. The greater film cooling efficiency with the coolant supply into triangular craters is explained by decrease in the intensity of secondary vortex structures (“kidney” vortex. This is due to the partial destruction and transformation of the coolant jets structure interacting with front wall of the crater. Simultaneously, the film cooling uniformity is increased in the span-wise direction.
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Brightening and Volatile Distribution Within Shackleton Crater Observed by the LRO Laser Altimeter.
Smith, D. E.; Zuber, M. T.; Head, J. W.; Neumann, G. A.; Mazarico, E.; Torrence, M. H.; Aharonson, O.; Tye, A. R.; Fassett, C. I.; Rosengurg, M. A.;
2012-01-01
Shackleton crater, whose interior lies largely in permanent shadow, is of interest due to its potential to sequester volatiles. Observations from the Lunar Orbiter Laser Altimeter onboard the Lunar Reconnaissance Orbiter have enabled an unprecedented topographic characterization, revealing Shackleton to be an ancient, unusually well-preserved simple crater whose interior walls are fresher than its floor and rim. Shackleton floor deposits are nearly the same age as the rim, suggesting little floor deposition since crater formation over 3 billion years ago. At 1064 nm the floor of Shackleton is brighter than the surrounding terrain and the interiors of nearby craters, but not as bright as the interior walls. The combined observations are explainable primarily by downslope movement of regolith on the walls exposing fresher underlying material. The relatively brighter crater floor is most simply explained by decreased space weathering due to shadowing, but a 1-mm-thick layer containing approx 20% surficial ice is an alternative possibility.
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Layers of 'Cabo Frio' in 'Victoria Crater'
2006-01-01
This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an approximately true color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.
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Mittlefehldt, D. W.; Gellert, R.; Van Bommel, S.; Arvidson, R. E.; Clark, B. C.; Ming, D. W.; Schroeder, C.; Yen, A. S.; Fox, V. K.; Farrand, W. H.;
2016-01-01
Mars Exploration Rover Opportunity has been exploring Mars for 12+ years, and is presently investigating the geology of a western rim segment of 22 kilometers diameter, Noachian- aged Endeavour crater. The Alpha Particle X-ray Spectrometer has determined the compositions of a pre-impact lithology, the Matijevic fm., and polymict impact breccias ejected from the crater, the Shoemaker fm. Opportunity is now investigating a region named Marathon Valley that cuts southwest-northeast through the central portion of the rim segment and provides a window into the lower stratigraphic record. (Geographic names used here are informal.) At the head of Marathon Valley, referred to here as Upper Marathon Valley, is a shallow, ovoid depression approximately 25×35 millimeters in size, named Spirit of Saint Louis. Layering inside Spirit of Saint Louis appears continuous with the Upper Marathon Valley rocks outside, indicating they are coeval. Spirit of Saint Louis is partly bounded by approximately 10-20 centimeters wide zone containing reddish altered rocks (red zone). Red zones also form prominent curvilinear features in Marathon Valley. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectra provide evidence for a really extensive Fe-Mg smectite in the Marathon Valley region, indicating distinct styles of aqueous alteration. The CRISM detections of smectites are based on metal-OH absorptions at approximately 2.3 and 2.4 micron that are at least two times the background noise level.
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Three astronauts inside Command Module Simulator during Apollo Simulation
1968-01-01
Three astronauts inside the Command Module Simulator in bldg 5 during an Apollo Simulation. Left to right are Astronauts Thomas P. Stafford, commander; John W. Young, command module pilot; and Eugene A. Cernan, lunar module pilot.
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O'Connell-Cooper, C. D.; Spray, J. G.; Thompson, L. M.; Gellert, R.; Berger, J. A.; Boyd, N. I.; Desouza, E. D.; Perrett, G. M.; Schmidt, M.; VanBommel, S. J.
2017-12-01
We present Alpha-Particle X-ray Spectrometer (APXS) data for the active Bagnold dune field within the Gale impact crater (Mars Science Laboratory (MSL) mission). We derive an APXS-based average basaltic soil (ABS) composition for Mars based on past and recent data from the MSL and Mars Exploration Rover (MER) missions. This represents an update to the Taylor and McLennan (2009) average Martian soil and facilitates comparison across Martian data sets. The active Bagnold dune field is compositionally distinct from the ABS, with elevated Mg, Ni, and Fe, suggesting mafic mineral enrichment and uniformly low levels of S, Cl, and Zn, indicating only a minimal dust component. A relationship between decreasing grain size and increasing felsic content is revealed. The Bagnold sands possess the lowest S/Cl of all Martian unconsolidated materials. Gale soils exhibit relatively uniform major element compositions, similar to Meridiani Planum and Gusev Crater basaltic soils (MER missions). However, they show minor enrichments in K, Cr, Mn, and Fe, which may signify a local contribution. The lithified eolian Stimson Formation within the Gale impact crater is compositionally similar to the ABS and Bagnold sands, which provide a modern analogue for these ancient eolian deposits. Compilation of APXS-derived soil data reveals a generally homogenous global composition for Martian soils but one that can be locally modified due to past or extant geologic processes that are limited in both space and time.
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Qualification of the APOLLO2 lattice physics code of the NURISP platform for WWER hexagonal lattices
International Nuclear Information System (INIS)
Hegyi, G.; Kereszturi, A.; Tota, A.
2011-01-01
The experiments performed at the ZR-6 zero critical reactor by the Temporary International Collective and a numerical assembly burnup benchmark specified for depletion calculation of a WWER-440 assembly containing gadolinium burnable poison were used to qualify the APOLLO2 (APOLLO2.8-E3) code as a part of its ongoing validation activity. The work is part of the NURISP project, where KFKI Atomic Energy Research Institute undertook to develop and qualify some calculation schemes for hexagonal problems. Concerning the ZR-6 measurements, single cell, macro cell and two-dimensional calculations of selected regular and perturbed experiments are being used for the validation. In the two-dimensional cases the radial leakage is also taken into account in the calculations together with the axial leakage represented by the measured axial buckling. Criticality parameter and reaction rate comparisons are presented. Although various sets of the experiments have been selected for the validation, good agreement of the measured and calculated parameters could be found by using the different options offered by APOLLO2. An additional mathematical benchmark-presented in the paper - also attests for the reliability of APOLLO2. All the test results prove the reliability of APOLLO2 for WWER core calculations. (Authors)
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Łukasiewicz, Kinga; Węgrzyn, Grzegorz
2016-01-01
An isolated population of apollo butterfly (Parnassius apollo, Lepidoptera: Papilionidae) occurs in Pieniny National Park (Poland). Deformations and reductions of wings in a relatively large number of individuals from this population is found, yet the reasons for these defects are unknown. During studies devoted to identify cause(s) of this phenomenon, we found that specific regions of genes coding of enzymes laccases 1 and 2 could not be amplified from DNA samples isolated from large fractions of malformed insects while expected PCR products were detected in almost all (with one exception) normal butterflies. Laccases (p-diphenol:dioxygen oxidoreductases) are oxidases containing several copper atoms. They catalyse single-electron oxidations of phenolic or other compounds with concomitant reduction of oxygen to water. In insects, their enzymatic activities were found previously in epidermis, midgut, Malpighian tubules, salivary glands, and reproductive tissues. Therefore, we suggest that defects in genes coding for laccases might contribute to deformation and reduction of wings in apollo butterflies, though it seems obvious that deficiency in these enzymes could not be the sole cause of these developmental improperties in P. apollo from Pieniny National Park.
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On the Moon with Apollo 15, A Guidebook to Hadley Rille and the Apennine Mountains.
Simmons, Gene
The booklet, published before the Apollo 15 mission, gives a timeline for the mission; describes and illustrates the physiography of the landing site; and describes and illustrates each lunar surface scientific experiment. Separate timelines are included for all traverses (the traverses are the Moon walks and, for Apollo 15, the Moon rides in the…
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Wagner, Michael M; Levander, John D; Brown, Shawn; Hogan, William R; Millett, Nicholas; Hanna, Josh
2013-01-01
This paper describes the Apollo Web Services and Apollo-SV, its related ontology. The Apollo Web Services give an end-user application a single point of access to multiple epidemic simulators. An end user can specify an analytic problem-which we define as a configuration and a query of results-exactly once and submit it to multiple epidemic simulators. The end user represents the analytic problem using a standard syntax and vocabulary, not the native languages of the simulators. We have demonstrated the feasibility of this design by implementing a set of Apollo services that provide access to two epidemic simulators and two visualizer services.
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Regolith history from cosmic-ray-produced isotopes
International Nuclear Information System (INIS)
Fireman, E.L.
1974-04-01
A statistical model is given for soil development relating meteoroid impacts on the moon to cosmic-ray-produced isotopes in the soil. By means of this model, the average lunar mass loss rate during the past 14 aeons is determined to be 170 g/sq cm aeon and the soil mixing rate to be approximately 200 cm/aeon from the gadolinium isotope data for the Apollo 15 and 16 drill stems. The isotope data also restrict the time variation of the meteoroid flux during the past 14 aeons. (U.S.)
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Apollo Anniversary: Moon Landing "Inspired World"
Institute of Scientific and Technical Information of China (English)
John Roach; 李然
2004-01-01
@@ On July 20, 1969, at 10:56 p.m. ET, Apollo 11 astronaut Neil Armstrong stepped onto the surface of the moon and said, "That' s one small step for man,one giant leap for mankind." Thirty-five years later, Steven Dick, NASA's chief historian at the space agency's headquarters in Washington, D.C. , said that a thousand years from now, that step may be considered the crowning① achievement of the 20th century.
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Apollo experience report: Earth landing system
West, R. B.
1973-01-01
A brief discussion of the development of the Apollo earth landing system and a functional description of the system are presented in this report. The more significant problems that were encountered during the program, the solutions, and, in general, the knowledge that was gained are discussed in detail. Two appendixes presenting a detailed description of the various system components and a summary of the development and the qualification test programs are included.
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2005-01-01
3 September 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows polygons enhanced by subliming seasonal frost in the martian south polar region. Polygons similar to these occur in frozen ground at high latitudes on Earth, suggesting that perhaps their presence on Mars is also a sign that there is or once was ice in the shallow subsurface. The circular features are degraded meteor impact craters. Location near: 72.2oS, 310.3oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring
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Schmidt, M. E.; King, P. L.; Gellert, R.; Elliott, B.; Thompson, L.; Berger, J.; Bridges, J.; Campbell, J. L; Grotzinger, J.; Hurowitz, J.;
2013-01-01
The Alpha Particle X-ray spectrometer (APXS) on the Curiosity rover in Gale Crater [1] is the 4th such instrument to have landed on Mars [2]. Along the rover's traverse down-section toward Glenelg (through sol 102), the APXS has examined four rocks and one soil [3]. Gale rocks are geochemically diverse and expand the range of Martian rock compositions to include high volatile and alkali contents (up to 3.0 wt% K2O) with high Fe and Mn (up to 29.2% FeO*).
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Stratigraphy of the crater Copernicus
Paquette, R.
1984-01-01
The stratigraphy of copernicus based on its olivine absorption bands is presented. Earth based spectral data are used to develop models that also employ cratering mechanics to devise theories for Copernican geomorphology. General geologic information, spectral information, upper and lower stratigraphic units and a chart for model comparison are included in the stratigraphic analysis.
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Digital Repository Service at National Institute of Oceanography (India)
ShyamPrasad, M.; Roy, S.K.; Gupta, A.
of the craters are of erosive type (Fig. 2), i.e., those which contain a central pit which is surrounded by radial and concentric cracks, indicative of high velocity impacts (Hörz et al., 1971). This could be misleading, as observed in our earlier studies... of very small particles at high relative velocities. This location also has 9 the highest spatial density of impacts, i.e., it contains 230 micro-craters/cm 2 of the ocean floor (Table 2). AAS 22/8 (4052 km): Location : 07 0 05.289’S & 78 0...
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Atypical pit craters on Mars: new insights from THEMIS, CTX and HiRISE observations
Cushing, Glen; Okubo, Chris H.; Titus, Timothy N.
2015-01-01
More than 100 pit craters in the Tharsis region of Mars exhibit morphologies, diameters and thermal behaviors that diverge from the much larger bowl-shaped pit craters that occur in most regions across Mars. These Atypical Pit Craters (APCs) generally have sharp and distinct rims, vertical or overhanging walls that extend down to their floors, surface diameters of ~50-350 m, and high depth-to-diameter (d/D) ratios that are usually greater than 0.3 (which is an upper-range value for impacts and bowl-shaped pit craters), and can exceed values of 1.8. Observations by the Mars Odyssey THermal Emission Imaging System (THEMIS) show that APC floor temperatures are warmer at night, and fluctuate with much lower diurnal amplitudes than nearby surfaces or adjacent bowl-shaped pit craters. Kīlauea volcano, Hawai'i, hosts pit craters that formed through subsurface collapse into active volcanic dikes, resulting in pits that can appear morphologically analogous to either APCs or bowl-shaped pit craters. Partially-drained dikes are sometimes exposed within the lower walls and floors of these terrestrial APC analogs and can form extensive cave systems with unique microclimates. Similar caves in martian pit craters are of great interest for astrobiology. This study uses new observations by the Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE) and Context Camera (CTX) to refine previous work where seven APCs were described from lower-resolution THEMIS visible-wavelength (VIS) observations. Here, we identify locations of 115 APCs, map their distribution across the Tharsis region, characterize their internal morphologies with high-resolution observations, and discuss possible formation mechanisms.
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Geology of drill hole USW VH-2, and structure of Crater Flat, southwestern Nevada
International Nuclear Information System (INIS)
Carr, W.J.; Parrish, L.D.
1985-01-01
A 1219 meter (4000 ft) drill hole in Crater Flat shows the absence of buried Pliocene or Quaternary volcanic rocks, and penetrates a section of Timber Mountain, Paintbrush, and the upper part of the Crater Flat Tuffs, similar to that exposed adjacent to Crater Flat. A prominent negative aeromagnetic anomaly between the drill hole and Bare Mountain is attributed to a westward thickening section of a reversely magnetized Miocene basalt. The relatively shallow depth of this basalt in the west-central part of Crater Flat indicates that no large amount of tectonic movement has occurred in approximately the last 10 m.y. Massive brecciated wedges of Paleozoic rocks are penetrated in two stratigraphic intervals in the drill hole; the older one, between the Tiva Canyon Member of the Paintbrush Tuff and the Rainier Mesa Member of the Timber Mountain Tuff, correlates with the time of maximum faulting east of Crater Flat in the Yucca Mountain area. The younger slide masses are correlated with a large slide block of probable late Miocene age exposed along the southwestern rim of Crater Flat. The structural pattern and style buried beneath central and western Crater Flat is deduced to be similar to that exposed at Yucca Mountain, but less developed. The major fault system controlling the steep east face of Bare Mountain, though probably still active, is believed to have developed mainly as a result of caldera collapse between 13 and 14 m.y. ago. Relations between faulting and four episodes of basalt eruption in the Crater Flat area strongly suggest contemporaneity of the two processes. 17 refs., 2 figs., 3 tabs
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Apollo experience report: Guidance and control systems. Engineering simulation program
Gilbert, D. W.
1973-01-01
The Apollo Program experience from early 1962 to July 1969 with respect to the engineering-simulation support and the problems encountered is summarized in this report. Engineering simulation in support of the Apollo guidance and control system is discussed in terms of design analysis and verification, certification of hardware in closed-loop operation, verification of hardware/software compatibility, and verification of both software and procedures for each mission. The magnitude, time, and cost of the engineering simulations are described with respect to hardware availability, NASA and contractor facilities (for verification of the command module, the lunar module, and the primary guidance, navigation, and control system), and scheduling and planning considerations. Recommendations are made regarding implementation of similar, large-scale simulations for future programs.
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Benton, E. V.; Henke, R. P.
1973-01-01
The high energy multicharged cosmic-ray-particle exposure of the Microbial Ecology Evaluation Device package on board the Apollo 16 spacecraft was monitored using cellulose nitrate, Lexan polycarbonate, nuclear emulsion, and silver chloride crystal nuclear-track detectors. The results of the analysis of these detectors include the measured particle fluences, the linear energy transfer spectra, and the integral atomic number spectrum of stopping particle density. The linear energy transfer spectrum is used to compute the fractional cell loss in human kidney (T1) cells caused by heavy particles. Because the Microbial Ecology Evaluation Device was better shielded, the high-energy multicharged particle exposure was less than that measured on the crew passive dosimeters.
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Preliminary results of soil radon gas survey of the Lake Bosomtwi impact crater
International Nuclear Information System (INIS)
Preko, S.; Danuor, S.K.; Menyeh, A.
2004-01-01
Soil radon gas survey was carried out in the Lake Bosomtwi impact crater area on eight profiles, which ran rapidly toward the end of the crater. One thousand soil samples, each weighing about 100g were acquired at a depth of 20 cm and at regular intervals of 10 m. The radon gas decay rate of the soil samples was then determined in the laboratory using the RDA-200 Radon detector and RDU-200 Degassing unit. It was found that generally areas south and east of the crater, which are severally sheared, faulted and fractured recorded high radon gas decay rates of the order of 800 counts/min whilst relatively undisturbed zones west of the crater recorded lower rates of the order of 20 counts/min. the cause of fracturing, shearing and faulting have been attributed to the effect of the meteorite impact in the Bosomtwi area, and therefore the results indicate that the soil radon gas survey could serve as a useful tool in mapping the impact-related structural characteristics of the crater. (author)
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Periodic Impact Cratering and Extinction Events Over the Last 260 Million Years
Rampino, Michael R.; Caldeira, Ken
2015-01-01
The claims of periodicity in impact cratering and biological extinction events are controversial. Anewly revised record of dated impact craters has been analyzed for periodicity, and compared with the record of extinctions over the past 260 Myr. A digital circular spectral analysis of 37 crater ages (ranging in age from 15 to 254 Myr ago) yielded evidence for a significant 25.8 +/- 0.6 Myr cycle. Using the same method, we found a significant 27.0 +/- 0.7 Myr cycle in the dates of the eight recognized marine extinction events over the same period. The cycles detected in impacts and extinctions have a similar phase. The impact crater dataset shows 11 apparent peaks in the last 260 Myr, at least 5 of which correlate closely with significant extinction peaks. These results suggest that the hypothesis of periodic impacts and extinction events is still viable.
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Moon Zoo: Making the public part of a crater survey algorithm
Gay, P. L.; Brown, S.; Huang, D.; Daus, C.; Lehan, C.; Robbins, S.
2011-10-01
The Moon Zoo citizen science website launched in May 2010 and invited the public to annotate images from the Lunar Reconnaissance Orbiter's Narrow Angle Camera (NAC). Tasks included marking the edges of craters with an ellipse tool, indicating where linear features (e.g. scarps) and special types of craters (e.g. dark haloed) are located with a box, and rating the number of boulders in an image. The goal of this project is to create crater and feature catalogues for large areas of the moon. In addition to doing science, Moon Zoo also seeks to educate its audience through educational content, to engage them through social media, and to understand them through research into their motivations and behaviors.
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Zhamanshin and Aouelloul - Craters produced by impact of tektite-like glasses?
O'Keefe, John A.
1987-01-01
It is shown that the enhanced abundance of siderophile elements and chromium in tektite-like glasses from the two impact craters of Zhamanshin and Aouelloul cannot be explained as a result of contamination of the country rock by meteorites nor, probably, comets. The pattern is, however, like that found in certain Australasian tektites, and in Ivory Coast tektites. It is concluded, in agreement with earlier suggestions by Campbell-Smith and Hey, that these craters were formed by the impact of large masses of tektite-like glass, of which the glasses which were studied are fragments. It follows that it is necessary, in considering an impact crater, to bear in mind that the projectile may have been a glass.
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Preliminary Results from Initial Investigations of Ceres' Cratering Record from Dawn Imaging Data
Schmedemann, Nico; Michael, Gregory; Ivanov, Boris A.; Kneissl, Thomas; Neesemann, Adrian; Hiesinger, Harald; Jaumann, Ralf; Raymond, Carol A.; Russell, Christopher T.
2015-04-01
The highly successful Dawn mission [1] finished data collection at Vesta in 2012 and is now on its way to the dwarf planet Ceres. According to the current Ceres approach timeline of the Dawn mission, the ground resolution of the Dawn FC camera [2] will be about 10 times better than Hubble data [3] at the time of the presentation of this work. This may allow for identification of craters about 15 km in diameter. Initial mapping of sample areas may provide enough information of the cratering record in order to compare it with the theoretical Ceres crater production function we present at the 46th LPSC conference (March 16-20, 2015, The Woodlands, Texas) [4]. Our preliminary crater production function for Ceres is derived from the assumption of an icy crust just below a thin surface layer of dust [5], and a projectile population that is very similar to the one that impacted the Moon [6]. In order to scale the lunar cratering record to Ceres we use the Ivanov scaling laws [7], which allow for crater scaling based on parameters that can be derived from observations. The lunar-like approach gave reasonable good results for the crater production function on the asteroids Vesta, Ida, Lutetia and Gaspra [8]. Since the lunar surface is of basaltic composition, the correct scaling between the different materials is challenging. One crucial parameter is the transition diameter from simple to complex craters. Based on the simple to complex transition diameter on Iapetus, an icy satellite of Saturn, we expect this transition at about 12 km crater size at Ceres. This value may be slightly different due to the different temperatures at Ceres and Iapetus. If the simple to complex transition is observed at much larger diameters, the reason could be a substantial fraction of rock in the shallow subsurface of Ceres. In an ice-rich surface material high relaxation rates may also be expected that could change the shape of the crater production function. A thorough geological mapping
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Age Distribution of Lunar Impact-Melt Rocks in Apollo Drive-Tube 68001/2
Curran, N. M.; Bower, D. M.; Frasl, B.; Cohen, B. A.
2018-01-01
Apollo 16 double-drive tube 68001 /68002 provides impact and volcanic materials along a depth of approximately 60 cm in five compositional distinct units. 68001 /2 offers the potential to study distinct populations of impact melts with depth to understand how 'gardening' affects these samples. We will use unbiased major-element chemistry, mineralogy, and age to understand the impact history of Apollo 16 landing site. The study demonstrates the techniques that landed missions require to identify lithologies of interest (e.g., impact melts).
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Apollo 8 prime crew seen during water egress training in Gulf of Mexico
1968-01-01
The prime crew of the Apollo 8 mission in life raft awaiting pickup by U.S. Coast Guard helicopter during water egress training in the Gulf of Mexico. They had just egressed Apollo Boilerplate 1102A, at left. Inflated bags were used to upright the boilerplate. Left to right, are Astronauts William A. Anders, lunar module pilot; James A. Lovell Jr., command module pilot; and Frank Borman, commander. A team of Manned Spacecraft Center (MSC) swimmers assisted with the training exercise.
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Geochemical monitoring of volcanic lakes. A generalized box model for active crater lakes
Directory of Open Access Journals (Sweden)
Franco Tassi
2011-06-01
Full Text Available
In the past, variations in the chemical contents (SO42−, Cl−, cations of crater lake water have not systematically demonstrated any relationships with eruptive activity. Intensive parameters (i.e., concentrations, temperature, pH, salinity should be converted into extensive parameters (i.e., fluxes, changes with time of mass and solutes, taking into account all the internal and external chemical–physical factors that affect the crater lake system. This study presents a generalized box model approach that can be useful for geochemical monitoring of active crater lakes, as highly dynamic natural systems. The mass budget of a lake is based on observations of physical variations over a certain period of time: lake volume (level, surface area, lake water temperature, meteorological precipitation, air humidity, wind velocity, input of spring water, and overflow of the lake. This first approach leads to quantification of the input and output fluxes that contribute to the actual crater lake volume. Estimating the input flux of the "volcanic" fluid (Qf- kg/s –– an unmeasurable subsurface parameter –– and tracing its variations with time is the major focus during crater lake monitoring. Through expanding the mass budget into an isotope and chemical budget of the lake, the box model helps to qualitatively characterize the fluids involved. The (calculated Cl− content and dD ratio of the rising "volcanic" fluid defines its origin. With reference to continuous monitoring of crater lakes, the present study provides tips that allow better calculation of Qf in the future. At present, this study offers the most comprehensive and up-to-date literature review on active crater lakes.
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Hypervelocity dust impact craters on photovoltaic devices imaged by ion beam induced charge
Energy Technology Data Exchange (ETDEWEB)
Yang, Changyi [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Wu, Yiyong; Lv, Gang [National Key Laboratory of Materials Behavior and Evaluation Technology in Space Environments, Harbin Institute of Technology, Harbin (China); Rubanov, Sergey [Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010 (Australia); Jamieson, David N., E-mail: d.jamieson@unimelb.edu.au [School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia)
2015-04-01
Hypervelocity dust has a speed of greater than 5 km/s and is a significant problem for equipment deployed in space such as satellites because of impacts that damage vulnerable components. Photovoltaic (PV) arrays are especially vulnerable because of their large surface area and the performance can be degraded owing to the disruption of the structure of the junction in the cells making up the array. Satellite PV arrays returned to Earth after service in orbit reveal a large number of craters larger than 5 μm in diameter arising from hypervelocity dust impacts. Extensive prior work has been done on the analysis of the morphology of craters in PV cells to understand the origin of the micrometeoroid that caused the crater and to study the corresponding mechanical damage to the structure of the cell. Generally, about half the craters arise from natural micrometeoroids, about one third from artificial Al-rich debris, probably from solid rocket exhausts, and the remainder from miscellaneous sources both known and unknown. However to date there has not been a microscopic study of the degradation of the electrical characteristics of PV cells exposed to hypervelocity dust impacts. Here we present an ion beam induced charge (IBIC) pilot study by a 2 MeV He microbeam of craters induced on a Hamamatsu PIN diode exposed to artificial hypervelocity Al dust from a dust accelerator. Numerous 5–30 μm diameter craters were identified and the charge collection efficiency of the crater and surrounds mapped with IBIC with bias voltages between 0 and 20 V. At highest bias, it was found the efficiency of the crater had been degraded by about 20% compared to the surrounding material. The speed distribution achieved in the Al dust accelerator was peaked at about 4 km/s compared to 11–68 km/s for dust encountered in low Earth orbit. We are able to extrapolate the charge collection efficiency degradation rate of unbiased cells in space based on our current measurements and the
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Hypervelocity dust impact craters on photovoltaic devices imaged by ion beam induced charge
International Nuclear Information System (INIS)
Yang, Changyi; Wu, Yiyong; Lv, Gang; Rubanov, Sergey; Jamieson, David N.
2015-01-01
Hypervelocity dust has a speed of greater than 5 km/s and is a significant problem for equipment deployed in space such as satellites because of impacts that damage vulnerable components. Photovoltaic (PV) arrays are especially vulnerable because of their large surface area and the performance can be degraded owing to the disruption of the structure of the junction in the cells making up the array. Satellite PV arrays returned to Earth after service in orbit reveal a large number of craters larger than 5 μm in diameter arising from hypervelocity dust impacts. Extensive prior work has been done on the analysis of the morphology of craters in PV cells to understand the origin of the micrometeoroid that caused the crater and to study the corresponding mechanical damage to the structure of the cell. Generally, about half the craters arise from natural micrometeoroids, about one third from artificial Al-rich debris, probably from solid rocket exhausts, and the remainder from miscellaneous sources both known and unknown. However to date there has not been a microscopic study of the degradation of the electrical characteristics of PV cells exposed to hypervelocity dust impacts. Here we present an ion beam induced charge (IBIC) pilot study by a 2 MeV He microbeam of craters induced on a Hamamatsu PIN diode exposed to artificial hypervelocity Al dust from a dust accelerator. Numerous 5–30 μm diameter craters were identified and the charge collection efficiency of the crater and surrounds mapped with IBIC with bias voltages between 0 and 20 V. At highest bias, it was found the efficiency of the crater had been degraded by about 20% compared to the surrounding material. The speed distribution achieved in the Al dust accelerator was peaked at about 4 km/s compared to 11–68 km/s for dust encountered in low Earth orbit. We are able to extrapolate the charge collection efficiency degradation rate of unbiased cells in space based on our current measurements and the
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A Virtual Petrological Microscope for All Apollo 11 Lunar Samples
Pillnger, C. T.; Tindle, A. G.; Kelley, S. P.; Quick, K.; Scott, P.; Gibson, E. K.; Zeigler, R. A.
2014-01-01
A means of viewing, over the Internet, polished thin sections of every rock in the Apollo lunar sample collections via software, duplicaing many of the functions of a petrological microscope, is described.
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Geologic field trip guide to Mount Mazama and Crater Lake Caldera, Oregon
Bacon, Charles R.; Wright, Heather M.
2017-08-08
Crater Lake partly fills one of the most spectacular calderas of the world—an 8 by 10 kilometer (km) basin more than 1 km deep formed by collapse of the Mount Mazama volcano during a rapid series of explosive eruptions ~7,700 years ago. Having a maximum depth of 594 meters (m), Crater Lake is the deepest lake in the United States. Crater Lake National Park, dedicated in 1902, encompasses 645 square kilometers (km2) of pristine forested and alpine terrain, including the lake itself, and virtually all of Mount Mazama. The geology of the area was first described in detail by Diller and Patton (1902) and later by Williams (1942), whose vivid account led to international recognition of Crater Lake as the classic collapse caldera. Because of excellent preservation and access, Mount Mazama, Crater Lake caldera, and the deposits formed by the climactic eruption constitute a natural laboratory for study of volcanic and magmatic processes. For example, the climactic ejecta are renowned among volcanologists as evidence for systematic compositional zonation within a subterranean magma chamber. Mount Mazama’s climactic eruption also is important as the source of the widespread Mazama ash, a useful Holocene stratigraphic marker throughout the Pacific Northwest United States, adjacent Canada, and offshore. A detailed bathymetric survey of the floor of Crater Lake in 2000 (Bacon and others, 2002) provides a unique record of postcaldera eruptions, the interplay between volcanism and filling of the lake, and sediment transport within this closed basin. Knowledge of the geology and eruptive history of the Mount Mazama edifice, enhanced by the caldera wall exposures, gives exceptional insight into how large volcanoes of magmatic arcs grow and evolve. In addition, many smaller volcanoes of the High Cascades beyond the limits of Mount Mazama provide information on the flux of mantle-derived magma through the region. General principles of magmatic and eruptive processes revealed by
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The central uplift of Ritchey crater, Mars
Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.
2015-01-01
Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.
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The central uplift of Ritchey crater, Mars
Ding, Ning; Bray, Veronica J.; McEwen, Alfred S.; Mattson, Sarah S.; Okubo, Chris H.; Chojnacki, Matthew; Tornabene, Livio L.
2015-05-01
Ritchey crater is a ∼79 km diameter complex crater near the boundary between Hesperian ridged plains and Noachian highland terrain on Mars (28.8°S, 309.0°E) that formed after the Noachian. High Resolution Imaging Science Experiment (HiRISE) images of the central peak reveal fractured massive bedrock and megabreccia with large clasts. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral analysis reveals low calcium pyroxene (LCP), olivine (OL), hydrated silicates (phyllosilicates) and a possible identification of plagioclase bedrock. We mapped the Ritchey crater central uplift into ten units, with 4 main groups from oldest and originally deepest to youngest: (1) megabreccia with large clasts rich in LCP and OL, and with alteration to phyllosilicates; (2) massive bedrock with bright and dark regions rich in LCP or OL, respectively; (3) LCP and OL-rich impactites draped over the central uplift; and (4) aeolian deposits. We interpret the primitive martian crust as igneous rocks rich in LCP, OL, and probably plagioclase, as previously observed in eastern Valles Marineris. We do not observe high-calcium pyroxene (HCP) rich bedrock as seen in Argyre or western Valles Marineris. The association of phyllosilicates with deep megabreccia could be from impact-induced alteration, either as a result of the Richey impact, or alteration of pre-existing impactites from Argyre basin and other large impacts that preceded the Ritchey impact, or both.
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Apollo-Soyuz test project: Composite of MSFC final science report
1977-01-01
Experimental procedures of nine experiments conducted during the Apollo-Soyuz Test Project mission from July 15th to July 24th, 1975 are presented. Conclusions and recommendations based on these experiments are given.
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ASTP crewmen in Apollo Command Module Trainer during training session at JSC
1975-01-01
The three members of the American ASTP prime crew are photographed inside the Apollo Command Module (CM) trainer in a water tank in bldg 260 during water egress training at JSC. They are, left to right, Astronauts Thomas P. Stafford, commander; Vance D. Brand, command module pilot; and Donald K. Slayton, docking module pilot (23430); Slayton attaches his life preserver as he egresses an Apollo Command Module trainer in a water tank in bldg 260 during water egresss training at JSC. Astronauts Brand (on left) and Stafford have already egressed the trainer and are seated in a three-man life raft.
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Apollo 11 crewmembers participate in water egress training in Gulf of Mexico
1969-01-01
The third member of the prime crew of the Apollo 11 lunar landing mission egresses Apollo Boilerplate 1102 during water egress training in the Gulf of Mexico. The other two crewmen are in raft. Taking part in the training were Astronauts Neil A. Armstrong, commander; Michael Collins, command module pilot; and Edwin E. Aldrin Jr., lunar module pilot. The three crewmen practiced donning and wearing biological isolation garments (B.I.G.) as a part of the exercise. The Manned Spacecraft Center (MSC) swimmer standing up, who assisted in the training, is also wearing a B.I.G.
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Energy Technology Data Exchange (ETDEWEB)
Uzonyi, I. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Department of Electrostatic Accelerators, H-4026 Debrecen, Bem ter 18/C (Hungary)]. E-mail: uzonyi@atomki.hu; Szoeor, Gy. [Department of Mineralogy and Geology, University of Debrecen, H-4010 Debrecen, Egyetem ter 1 (Hungary); Vekemans, B. [Department of Chemistry, University of Antwerpen (UIA) Universiteitsplein 1, B-2610 Wilrijk (Belgium); Vincze, L. [Department of Chemistry, University of Antwerpen (UIA) Universiteitsplein 1, B-2610 Wilrijk (Belgium); Rozsa, P. [Department of Mineralogy and Geology, University of Debrecen, H-4010 Debrecen, Egyetem ter 1 (Hungary); Szabo, Gy. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Department of Electrostatic Accelerators, H-4026 Debrecen, Bem ter 18/C (Hungary); Somogyi, A. [ID22, ESRF, 6 rue Jules Horowitz, BP 220, F-38043 Grenoble Cedex (France); Adams, F. [Department of Chemistry, University of Antwerpen (UIA) Universiteitsplein 1, B-2610 Wilrijk (Belgium); Kiss, A.Z. [Institute of Nuclear Research of the Hungarian Academy of Sciences, Department of Electrostatic Accelerators, H-4026 Debrecen, Bem ter 18/C (Hungary)
2004-10-08
A combined micro-PIXE and micro-SRXRF method has been used for the characterization of impact materials collected at the well-known Barringer Meteor Crater. Elemental maps were recorded and concentrations were determined by micro-PIXE method for the major constituents of samples. Micro-SRXRF technique was used for the complementary measurement of medium and high atomic number elements, especially the siderophilic ones. Altogether, approximately 40 elements were analyzed. These results elucidate many steps of the formation mechanism of the various impact-metamorphosed objects.
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Potter, Ross W. K.; Head, James W.; Guo, Dijun; Liu, Jianzhong; Xiao, Long
2018-05-01
The 492 km-diameter Apollo impact basin post-dates, and is located at the inner edge of, the ∼2240 km-diameter South Pole-Aitken (SPA) basin, providing an opportunity to assess the SPA substructure and lateral heterogeneity. Gravity Recovery and Interior Laboratory gravity data suggest an average crustal thickness on the floor of SPA of ∼20 km and within the Apollo basin of ∼5 km, yet remote sensing data reveal no conclusive evidence for the presence of exposed mantle material. We use the iSALE shock physics code to model the formation of the Apollo basin and find that the observational data are best fit by the impact of a 40 km diameter body traveling at 15 km/s into 20-40 km thick crustal material. These results strongly suggest that the Apollo impact occurred on ejecta deposits and collapsed crustal material of the SPA basin and could help place constraints on the location, size and geometry of the SPA transient cavity. The peak ring in the interior of Apollo basin is plausibly interpreted to be composed of inwardly collapsed lower crustal material that experienced peak shock pressures in excess of 35 GPa, consistent with remote sensing observations that suggest shocked plagioclase. Proposed robotic and/or human missions to SPA and Apollo would present an excellent opportunity to test the predictions of this work and address many scientific questions about SPA basin evolution and structure.
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Global and local re-impact and velocity regime of ballistic ejecta of boulder craters on Ceres
Schulzeck, F.; Schröder, S. E.; Schmedemann, N.; Stephan, K.; Jaumann, R.; Raymond, C. A.; Russell, C. T.
2018-04-01
Imaging by the Dawn-spacecraft reveals that fresh craters on Ceres below 40 km often exhibit numerous boulders. We investigate how the fast rotating, low-gravity regime on Ceres influences their deposition. We analyze size-frequency distributions of ejecta blocks of twelve boulder craters. Global and local landing sites of boulder crater ejecta and boulder velocities are determined by the analytical calculation of elliptic particle trajectories on a rotating body. The cumulative distributions of boulder diameters follow steep-sloped power-laws. We do not find a correlation between boulder size and the distance of a boulder to its primary crater. Due to Ceres' low gravitational acceleration and fast rotation, ejecta of analyzed boulder craters (8-31 km) can be deposited across the entire surface of the dwarf planet. The particle trajectories are strongly influenced by the Coriolis effect as well as the impact geometry. Fast ejecta of high-latitude craters accumulate close to the pole of the opposite hemisphere. Fast ejecta of low-latitude craters wraps around the equator. Rotational effects are also relevant for the low-velocity regime. Boulders are ejected at velocities up to 71 m/s.
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Geologic Map of Mount Mazama and Crater Lake Caldera, Oregon
Bacon, Charles R.
2008-01-01
Crater Lake partly fills one of the most spectacular calderas of the world, an 8-by-10-km basin more than 1 km deep formed by collapse of the volcano known as Mount Mazama (fig. 1) during a rapid series of explosive eruptions about 7,700 years ago. Having a maximum depth of 594 m, Crater Lake is the deepest lake in the United States. Crater Lake National Park, dedicated in 1902, encompasses 645 km2 of pristine forested and alpine terrain, including the lake itself, virtually all of Mount Mazama, and most of the area of the geologic map. The geology of the area was first described in detail by Diller and Patton (1902) and later by Williams (1942), whose vivid account led to international recognition of Crater Lake as the classic collapse caldera. Because of excellent preservation and access, Mount Mazama, Crater Lake caldera, and the deposits formed by the climactic eruption constitute a natural laboratory for study of volcanic and magmatic processes. For example, the climactic ejecta are renowned among volcanologists as evidence for systematic compositional zonation within a subterranean magma chamber. Mount Mazama's climactic eruption also is important as the source of the widespread Mazama ash, a useful Holocene stratigraphic marker throughout the Pacific Northwest, adjacent Canada, and offshore. A detailed bathymetric survey of the floor of Crater Lake in 2000 (Bacon and others, 2002) provides a unique record of postcaldera eruptions, the interplay between volcanism and filling of the lake, and sediment transport within this closed basin. Knowledge of the geology and eruptive history of the Mount Mazama edifice, greatly enhanced by the caldera wall exposures, gives exceptional insight into how large volcanoes of magmatic arcs grow and evolve. Lastly, the many smaller volcanoes of the High Cascades beyond the limits of Mount Mazama are a source of information on the flux of mantle-derived magma through the region. General principles of magmatic and eruptive
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1973-01-01
The requirements for processing, packaging, testing, and shipment of foods selected for use in the Apollo food system are presented. Specific foodstuffs chosen from the following categories are discussed: (1) soups; (2) juices; (3) breads; (4) meat and poultry products; (5) fruits and nuts; (6) desserts; and (7) beverages. Food procurement for the mobile quarantine facility and for Apollo preflight and postflight activities is also discussed.
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Apollo 12, A New Vista for Lunar Science.
National Aeronautics and Space Administration, Washington, DC.
Man's second lunar landing, Apollo 12, provided a wealth of scientific information about the moon. The deployment of the magnetometer, seismometer, and ionosphere detector, and other activities on the lunar surface are described. A number of color photographs show the astronauts setting up equipment on the moon as well as close-ups of the lunar…
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Magma genesis at Gale Crater: Evidence for Pervasive Mantle Metasomatism
Filiberto, J.
2017-12-01
Basaltic rocks have been analyzed at Gale Crater with a larger range in bulk chemistry than at any other landing site [1]. Therefore, the rocks may have experienced significantly different formation conditions than those experienced by magmas at Gusev Crater or Meridiani Planum. Specifically, the rocks at Gale Crater have higher potassium than other Martian rocks, with a potential analog of the Nakhlite parental magma, and are consistent with forming from a metasomatized mantle source [2-4]. Mantle metasomatism would not only affect the bulk chemistry but mantle melting conditions, as metasomatism fluxes fluids into the source region. Here I will combine differences in bulk chemistry between Martian basalts to calculate formation conditions in the interior and investigate if the rocks at Gale Crater experienced magma genesis conditions consistent with metasomatism - lower temperatures and pressures of formation. To calculate average formation conditions, I rely on experimental results, where available, and silica-activity and Mg-exchange thermometry calculations for all other compositions following [5, 6]. The results show that there is a direct correlation between the calculated mantle potential temperature and the K/Ti ratio of Gale Crater rocks. This is consistent with fluid fluxed metasomatism introducing fluids to the system, which depressed the melting temperature and fluxed K but not Ti to the system. Therefore, all basalts at Gale Crater are consistent with forming from a metasomatized mantle source, which affected not only the chemistry of the basalts but also the formation conditions. References: [1] Cousin A. et al. (2017) Icarus. 288: 265-283. [2] Treiman A.H. et al. (2016) Journal of Geophysical Research: Planets. 121: 75-106. [3] Treiman A.H. and Medard E. (2016) Geological Society of America Abstracts with Programs. 48: doi: 10.1130/abs/2016AM-285851. [4] Schmidt M.E. et al. (2016) Geological Society of America Abstracts with Programs. 48: doi: 10
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Virtual Microscope Views of the Apollo 11 and 12 Lunar Samples
Gibson, E. K.; Tindle, A. G.; Kelley, S. P.; Pillinger, J. M.
2016-01-01
The Apollo virtual microscope is a means of viewing, over the Internet, polished thin sections of every rock in the Apollo lunar sample collections via software, duplicating many of the functions of a petrological microscope, is described. Images from the Apollo 11 and 12 missions may be viewed at: www.virtualmicroscope.org/content/apollo. Introduction: During the six NASA missions to the Moon from 1969-72 a total of 382 kilograms of rocks and soils, often referred to as "the legacy of Apollo", were collected and returned to Earth. A unique collection of polished thin sections (PTSs) was made from over 400 rocks by the Lunar Sample Curatorial Facility at the Johnson Spacecraft Center (JSC), Houston. These materials have been available for loan to approved PIs but of course they can't be simultaneously investigated by several researchers unless they are co-located or the sample is passed back and forward between them by mail/hand carrying which is inefficient and very risky for irreplaceable material. When The Open University (OU), the world's largest Distance Learning Higher Education Establishment found itself facing a comparable problem (how to supply thousands of undergraduate students with an interactive petrological microscope and a personal set of thin sections), it decided to develop a software tool called the Virtual Microscope (VM). As a result it is now able to make the unique and precious collection of Apollo specimens universally available as a resource for concurrent study by anybody in the world's Earth and Planetary Sciences community. Herein, we describe the first steps of a collaborative project between OU and the Johnson Space Center (JSC) Curatorial Facility to record a PTS for every lunar rock, beginning with those collected by the Apollo 11 and 12 missions. Method: Production of a virtual microscope dedicated to a particular theme divides into four main parts - photography, image processing, building and assembly of virtual microscope
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Sulfate-rich eolian and wet interdune deposits, erebus crater, meridiani Planum, Mars
Metz, J.M.; Grotzinger, J.P.; Rubin, D.M.; Lewis, K.W.; Squyres, S. W.; Bell, J.F.
2009-01-01
This study investigates three bedrock exposures at Erebus crater, an ?? 300 m diameter crater approximately 4 km south of Endurance crater on Mars. These outcrops, called Olympia, Payson, and Yavapai, provide additional evidence in support of the dune-interdune model proposed for the formation of the deposits at the Opportunity landing site in Meridiani Planum. There is evidence for greater involvement of liquid water in the Olympia outcrop exposures than was observed in Eagle or Endurance craters. The Olympia outcrop likely formed in a wet interdune and sand sheet environment. The facies observed within the Payson outcrop, which is likely stratigraphically above the Olympia outcrop, indicate that it was deposited in a damp-wet interdune, sand sheet, and eolian dune environment. The Yavapai outcrop, which likely stratigraphically overlies the Payson outcrop, indicates that it was deposited in primarily a sand sheet environment and also potentially in an eolian dune environment. These three outcrop exposures may indicate an overall drying-upward trend spanning the stratigraphic section from its base at the Olympia outcrop to its top at the Yavapai outcrop. This contrasts with the wetting-upward trend seen in Endurance and Eagle craters. Thus, the series of outcrops seen at Meridiani by Opportunity may constitute a full climatic cycle, evolving from dry to wet to dry conditions. ?? 2009, SEPM (Society for Sedimentary Geology).
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Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure
Poag, C.W.
2005-01-01
This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact craters. The inner boundary of the eastern rim (rim wall) is formed by a series of raterfacing, steep scarps, 15-60 m high. In combination, these rim-wall scarps represent the footwalls of a system of crater-encircling normal faults, which are downthrown toward the crater. Outboard of the rim wall are several additional normal-fault blocks, whose bounding faults trend approximately parallel to the rim wall. The tops of the outboard fault blocks form two distinct, parallel, flat or gently sloping, terraces. The innermost terrace (Terrace 1) can be identified on each profile, but Terrace 2 is only sporadically present. The terraced fault blocks are composed mainly of nonmarine, poorly to moderately consolidated, siliciclastic sediments, belonging to the Lower Cretaceous Potomac Formation. Though the ridge-forming geometry of the eastern rim gives the appearance of a raised compressional feature, no compelling evidence of compressive forces is evident in the profiles studied. The structural mode, instead, is that of extension, with the clear dominance of normal faulting as the extensional mechanism.
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Astronaut John Young in Command Module Simulator during Apollo Simulation
1968-01-01
Astronaut John W. Young, command module pilot, inside the Command Module Simulator in bldg 5 during an Apollo Simulation. Astronauts Thomas P. Stafford, commander and Eugene A. Cernan, lunar module pilot are out of the view.
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Delineating Bukit Bunuh impact crater boundary by geophysical and geotechnical investigation
Energy Technology Data Exchange (ETDEWEB)
Azwin, I. N., E-mail: nurazwinismail@yahoo.com; Rosli, S.; Nordiana, M. M.; Ragu, R. R.; Mark, J. [Geophysics Section, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Mokhtar, S. [Centre for Global Archaeological Research Malaysia, 11800 USM, Penang (Malaysia)
2015-03-30
Evidences of crater morphology and shock metamorphism in Bukit Bunuh, Lenggong, Malaysia were found during the archaeological research conducted by the Centre for Global Archaeological Research Malaysia, Universiti Sains Malaysia. In order to register Bukit Bunuh as one of the world meteorite impact site, detailed studies are needed to verify the boundary of the crater accordingly. Geophysical study was conducted utilising the seismic refraction and 2-D electrical resistivity method. Seismic refraction survey was done using ABEM MK8 24 channel seismograph with 14Hz geophones and 40kg weight drop while 2-D electrical resistivity survey was performed using ABEM SAS4000 Terrameter and ES10-64C electrode selector with pole-dipole array. Bedrock depths were digitized from the sections obtained. The produced bedrock topography map shows that there is low bedrock level circulated by high elevated bedrock and interpreted as crater and rim respectively with diameter approximately 8km. There are also few spots of high elevated bedrock appear at the centre of the crater which interpreted as rebounds zone. Generally, the research area is divided into two layers where the first layer with velocity 400-1100 m/s and resistivity value of 10-800 Om predominantly consists of alluvium mix with gravel and boulders. Second layer represents granitic bedrock with depth of 5-50m having velocity >2100 m/s and resistivity value of >1500 Om. This research is strengthen by good correlation between geophysical data and geotechnical borehole records executed inside and outside of the crater, on the rim, as well as at the rebound area.
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International Nuclear Information System (INIS)
Azwin, I N; Saad, Rosli; Nordiana, M M; Bery, Andy Anderson; Hidayah, I N E; Saidin, Mokhtar
2015-01-01
Interest in studying impact crater on earth has increased tremendously due to its importance in geologic events, earth inhabitant history as well as economic value. The existences of few shock metamorphism and crater morphology evidences are discovered in Bukit Bunuh, Malaysia thus detailed studies are performed using geophysical and geotechnical methods to verify the type of the crater and characteristics accordingly. This paper presents the combined analysis of 2-D electrical resistivity, seismic refraction, geotechnical SPT N value, moisture content and RQD within the study area. Three stages of data acquisition are made starting with regional study followed by detailed study on West side and East side. Bulk resistivity and p-wave seismic velocity were digitized from 2-D resistivity and seismic sections at specific distance and depth for corresponding boreholes and samples taken. Generally, Bukit Bunuh shows the complex crater characteristics. Standard table of bulk resistivity and p-wave seismic velocity against SPT N value, moisture content and RQD are produce according to geological classifications of impact crater; inside crater, rim/slumped terrace and outside crater
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Azwin, I. N.; Saad, Rosli; Saidin, Mokhtar; Nordiana, M. M.; Anderson Bery, Andy; Hidayah, I. N. E.
2015-01-01
Interest in studying impact crater on earth has increased tremendously due to its importance in geologic events, earth inhabitant history as well as economic value. The existences of few shock metamorphism and crater morphology evidences are discovered in Bukit Bunuh, Malaysia thus detailed studies are performed using geophysical and geotechnical methods to verify the type of the crater and characteristics accordingly. This paper presents the combined analysis of 2-D electrical resistivity, seismic refraction, geotechnical SPT N value, moisture content and RQD within the study area. Three stages of data acquisition are made starting with regional study followed by detailed study on West side and East side. Bulk resistivity and p-wave seismic velocity were digitized from 2-D resistivity and seismic sections at specific distance and depth for corresponding boreholes and samples taken. Generally, Bukit Bunuh shows the complex crater characteristics. Standard table of bulk resistivity and p-wave seismic velocity against SPT N value, moisture content and RQD are produce according to geological classifications of impact crater; inside crater, rim/slumped terrace and outside crater.
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Siegal, B. S.; Wickman, F. E.
1973-01-01
An empirical linear relationship has been established by Pike (1967) between the overall diameter and the rim crest diameter for rimmed, flat-floored as well as bowl-shaped, lunar and terrestrial craters formed by impact and explosion. A similar relationship for experimentally formed fluidization craters has been established by Siegal (1971). This relationship is examined in terms of the geometry of the crater and the slope angles of loose materials. The parameter varies from 1.40 to 1.65 and is found to be dependent on mean interior flat floor radius, exterior and interior rim slope angles, angle of aperture of the crater cone, and the volume fraction of crater void accounted for in the rim. The range of the observed parameter can be understood in terms of simple crater geometry by realistic values of the five parameters.
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Impact cratering on granular beds: From the impact of raindrops to the strike of hailstones
Gordillo, Leonardo; Wang, Junping; Japardi, Fred; Teddy, Warren; Gao, Ming; Cheng, Xiang
Impact craters generated by the impact of a spherical object onto a granular bed strongly depend on the material properties of impactors. As an example, impact cratering by liquid drops and by solid spheres exhibits qualitatively different power-law scalings for the size of resulting impact craters. While the basic energy conservation and dimensional analysis provide simple guiding rules, the detailed dynamics governing the relation between these power-law scalings is still far from clear. To analyze the transition between liquid-drop and solid-sphere impact cratering, we investigate impact cratering by liquid drops for a wide range of viscosities over 7 decades. Using high-speed photography and laser profilometry, we delineate the liquid-to-solid transition and show the emergence of the two asymptotic behaviors and their respective power laws. We find that granular avalanches triggered by impacts are crucial in understanding the energy partition between impacted surfaces and impactors, which directly determines the observed scaling relations. A simple model is constructed for the initial stage of the impact that explains the energy partition during crater formation. We ackowledge the support of NSF CAREER DMR-1452180. LG acknowledges fundings from CONICYT/BECAS CHILE 74160007.
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Photogrammetry of Apollo 15 photography, part C
Wu, S. S. C.; Schafer, F. J.; Jordan, R.; Nakata, G. M.; Derick, J. L.
1972-01-01
In the Apollo 15 mission, a mapping camera system and a 61 cm optical bar, high resolution panoramic camera, as well as a laser altimeter were used. The panoramic camera is described, having several distortion sources, such as cylindrical shape of the negative film surface, the scanning action of the lens, the image motion compensator, and the spacecraft motion. Film products were processed on a specifically designed analytical plotter.
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Layers of 'Cabo Frio' in 'Victoria Crater' (Stereo)
2006-01-01
This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is a red-blue stereo anaglyph generated from images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 430-nanometer filters.
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Continued monitoring of aeolian activity within Herschel Crater, Mars
Cardinale, Marco; Pozzobon, Riccardo; Michaels, Timothy; Bourke, Mary C.; Okubo, Chris H.; Chiara Tangari, Anna; Marinangeli, Lucia
2017-04-01
In this work, we study a dark dune field on the western side of Herschel crater, a 300 km diameter impact basin located near the Martian equator (14.4°S, 130°E), where the ripple and dune motion reflects the actual atmospheric wind conditions. We develop an integrated analysis using (1) automated ripple mapping that yields ripple orientations and evaluates the spatial variation of actual atmospheric wind conditions within the dunes, (2) an optical cross-correlation that allows us to quantify an average ripple migration rate of 0.42 m per Mars year, and (3) mesoscale climate modeling with which we compare the observed aeolian changes with modeled wind stresses and directions. Our observations are consistent with previous work [1] [2] that detected aeolian activity in the western part of the crater. It also demonstrates that not only are the westerly Herschel dunes movable, but that predominant winds from the north are able to keep the ripples and dunes active within most (if not all) of Herschel crater in the current atmospheric conditions. References: [1] Cardinale, M., Silvestro, S., Vaz, D.A., Michaels, T., Bourke, M.C., Komatsu, G., Marinangeli, L., 2016. Present-day aeolian activity in Herschel Crater, Mars. Icarus 265, 139-148. doi:10.1016/j.icarus.2015.10.022. [2] Runyon, K.D., Bridges, N.T., Ayoub, F., Newman, C.E. and Quade, J.J., 2017. An integrated model for dune morphology and sand fluxes on Mars. Earth and Planetary Science Letters, 457, pp.204-212.
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Apollo 11 Commander Armstrong Presents President With Commemorative Plaque
1974-01-01
On June 4, 1974, 5 years after the successful Apollo 11 lunar landing mission, commander Neil Armstrong (right) presented a plaque to U.S. President Richard Milhous Nixon (left) on behalf of all people who had taken part in the space program. In making the presentation, Armstrong said 'Mr. President, you have proclaimed this week to be United States Space week in conjunction with the fifth anniversary of our first successful landing on the Moon. It is my privilege to represent my colleagues, the crewmen of projects Mercury, Gemini, Apollo, and Skylab, and the men and women of NASA, and the hundreds of thousands of Americans from across the land who contributed so mightily to the success of our efforts in space in presenting this plaque which bears the names of each individual who has had the privilege of representing this country' in a space flight. The presentation was made at the California white house in San Clemente.
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An absolute calibration system for millimeter-accuracy APOLLO measurements
Adelberger, E. G.; Battat, J. B. R.; Birkmeier, K. J.; Colmenares, N. R.; Davis, R.; Hoyle, C. D.; Huang, L. R.; McMillan, R. J.; Murphy, T. W., Jr.; Schlerman, E.; Skrobol, C.; Stubbs, C. W.; Zach, A.
2017-12-01
Lunar laser ranging provides a number of leading experimental tests of gravitation—important in our quest to unify general relativity and the standard model of physics. The apache point observatory lunar laser-ranging operation (APOLLO) has for years achieved median range precision at the ∼2 mm level. Yet residuals in model-measurement comparisons are an order-of-magnitude larger, raising the question of whether the ranging data are not nearly as accurate as they are precise, or if the models are incomplete or ill-conditioned. This paper describes a new absolute calibration system (ACS) intended both as a tool for exposing and eliminating sources of systematic error, and also as a means to directly calibrate ranging data in situ. The system consists of a high-repetition-rate (80 MHz) laser emitting short (motivating continued work on model capabilities. The ACS provides the means to deliver APOLLO data both accurate and precise below the 2 mm level.
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Tectonic and volcanic implications of a cratered seamount off Nicobar Island, Andaman Sea
Digital Repository Service at National Institute of Oceanography (India)
KameshRaju, K.A.; Ray, D.; Mudholkar, A.V.; Murty, G.P.S.; Gahalaut, V.K.; Samudrala, K.; Paropkari, A.L.; Ramachandran, R.; SuryaPrakash, L.
seamount with well-developed crater at the summit was discovered near to the center of the Nicobar swarm. Rock samples collected by TV-guided grab from the seamount crater are dacite, rhyolite and andesite type with a veneer of ferromanganese oxide coating...
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Phoebus volentem proelia me loqui: The Apollo of Callimachus in Horace
Directory of Open Access Journals (Sweden)
Kristina Tomc
2010-07-01
Full Text Available The Augustan poets often modelled their recusationes on Callimachus’ portrayal of Apollo in theAetiaPrologue. The paper discusses parallel passages in Horace’s oeuvre, illustrating some typical characteristics of Horace’s poetry and of his attitude to his poetic models. After a brief introduction, the paper first touches on three poems by Horace where the role of Callimachus’ Apollo is taken over by another deity: the Muse in C. 1.6.10-12, Venus in C. 1.19.9-12, and adeus (presumably Cupid in Epod. 14.6-8. The three examples display similarities to, rather than identity with, the Callimachean situation: instead of supplying a direct quote, Horace merely reports the words of a ῾higher power’ which allegedly prevented him from writing what he wanted or what was expected of him. In the two Odes Horace thus refuses to compose an epic, while Epode 14 is not a typical recusatio: Horace’s polished iambics paradoxically profess his inability to compose iambic poetry, and his preference for erotic lyric poetry. The next section focuses on Satire 1.10.31-35, which portrays the Roman god Quirinus warning the young poet in a dream that writing Greek verse is pointless. An analysis of this complex programmatic satire reveals continual departures from, and approximations to, Callimachean poetic, as Horace interweaves several, at times clearly irreconcilable, traditions. Indeed, Callimachean poetic itself is not unequivocal or monolithic but contains many tensions. The short fourth section discusses Horace’s prayer to Mercury in Satire 2.6.13-15. Although superficially lacking a ῾programmatic’ dimension, the satire in fact contains several allusions to Callimachus. It serves to show that Horace’s images function at several levels at once, and that his satires closely interweave ethics with aesthetics. The final and longest section focuses on Horace’s last poem, C. 4.15. In the first strophe, Horace is finally given
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1974-01-01
Operational and configuration checks for the Apollo-Soyuz Test Project are presented. The checks include: backup crew prelaunch, prime crew prelaunch, boost and insertion, G and C reference data, G and N reference modes, rendezvous, navigation, Apollo-Soyuz operations, abort procedures, and emergency procedures.
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Secondary ion mass spectrometry induced damage adjacent to analysis craters in silicon
International Nuclear Information System (INIS)
Clark, M.H.; Jones, K.S.; Stevie, F.A.
2002-01-01
Damage introduced by dynamic secondary ion mass spectrometry (SIMS) depth profiling is studied. A silicon sample with a boron marker layer was depth profiled by dynamic SIMS. After subsequent annealing at 750 deg. C for 30 min, the SIMS sample was reanalyzed by plan-view transmission electron microscope (PTEM) and SIMS. PTEM images showed the presence of interstitial defects near the original SIMS crater, and SIMS depth profiles of similar regions exhibited boron diffusivity enhancements. Excess interstitials were introduced into the Si surface up to 2 mm from the original 225 μmx225 μm crater. Both PTEM and SIMS results showed that the damage and its effects diminished with an increase in distance from the original crater
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Constraints on the Volatile Distribution Within Shackleton Crater at the Lunar South Pole
Zuber, Maria T.; Head, James W.; Smith, David E.; Neumann, Gregory A.; Mazarico, Erwan; Torrence, Mark H.; Aharonson, Oded; Tye, Alexander R.; Fassett, Caleb I.; Rosenburg, Margaret A.;
2012-01-01
Shackleton crater is nearly coincident with the Moon's south pole. Its interior receives almost no direct sunlight and is a perennial cold trap, making Shackleton a promising candidate location in which to seek sequestered volatiles. However, previous orbital and Earth-based radar mapping and orbital optical imaging have yielded conflicting interpretations about the existence of volatiles. Here we present observations from the Lunar Orbiter Laser Altimeter on board the Lunar Reconnaissance Orbiter, revealing Shackleton to be an ancient, unusually well-preserved simple crater whose interior walls are fresher than its floor and rim. Shackleton floor deposits are nearly the same age as the rim, suggesting that little floor deposition has occurred since the crater formed more than three billion years ago. At a wavelength of 1,064 nanometres, the floor of Shackleton is brighter than the surrounding terrain and the interiors of nearby craters, but not as bright as the interior walls. The combined observations are explicable primarily by downslope movement of regolith on the walls exposing fresher underlying material. The relatively brighter crater floor is most simply explained by decreased space weathering due to shadowing, but a one-micrometre-thick layer containing about 20 per cent surficial ice is an alternative possibility.
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Graettinger, A. H.
2018-05-01
A maar crater is the top of a much larger subsurface diatreme structure produced by phreatomagmatic explosions and the size and shape of the crater reflects the growth history of that structure during an eruption. Recent experimental and geophysical research has shown that crater complexity can reflect subsurface complexity. Morphometry provides a means of characterizing a global population of maar craters in order to establish the typical size and shape of features. A global database of Quaternary maar crater planform morphometry indicates that maar craters are typically not circular and frequently have compound shapes resembling overlapping circles. Maar craters occur in volcanic fields that contain both small volume and complex volcanoes. The global perspective provided by the database shows that maars are common in many volcanic and tectonic settings producing a similar diversity of size and shape within and between volcanic fields. A few exceptional populations of maars were revealed by the database, highlighting directions of future research to improve our understanding on the geometry and spacing of subsurface explosions that produce maars. These outlying populations, such as anomalously large craters (>3000 m), chains of maars, and volcanic fields composed of mostly maar craters each represent a small portion of the database, but provide opportunities to reinvestigate fundamental questions on maar formation. Maar crater morphometry can be integrated with structural, hydrological studies to investigate lateral migration of phreatomagmatic explosion location in the subsurface. A comprehensive database of intact maar morphometry is also beneficial for the hunt for maar-diatremes on other planets.
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Validation de schemas de calcul APOLLO3 pour assemblages de type RNR
Berche, Simon
The next generation nuclear reactors are already under construction or under development in the R&D labs around the world. The 3rd and 4th generation nuclear reactors will need a neutronic calculation code able to deal with any kind of technology (FBR or PWR for example). APOLLO3, a new neutronic code developped by the Commissariat a l'Energie Atomique, will receive the heritage of his two predecessors, APOLLO2 (PWR) and ECCO/ERANOS (FBR), and to play a major role in the design of the next nuclear reactors. Validation is an essential step along the development of a deterministic neutronic code. It comes right after implementation and verification and it gives the team in charge of the calculation models in Cadarache the necessary feedbacks on the code's behaviour in various situations. This thesis goal is to suggest a validation (without evolution) of the current APOLLO3 reference calculation route used for FBR. This validation is supposed to be as complete as possible and to cover various configurations. This work will be a preparatory work for the complete validation which will be performed by the APOLLO3 project team in Cadarache. This validation is based on a study of various configurations composed of basic elements like pincells or assemblies. To complete this task, we study different aspects : geometry, sodium void effect, AEMC-RNR-1200 energy mesh, JEFF3.2 nuclear data evaluation for Pu239. We conduct a macroscopical study (multiplication factor, reactivity, neutron flux,...) and an isotopical study (fission and capture rates for Pu239 and U238 for example). We use TRIPOLI4, a Monte-Carlo simulation code, as a reference for all of our APOLLO3 calculations. We consider an infinite lattice (no neutron leakage model keff = kinfinity). This first validation phase led us to several conclusions. First of all, we observed that the geometrical configuration defined for the single pincell used in ASTRID predefinition studies is heterogeneous enough. Indeed, void
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Micro-Crater Laser Induced Breakdown Spectroscopy--an Analytical approach in metals samples
Energy Technology Data Exchange (ETDEWEB)
Piscitelli, Vincent [UCV- Laboratorio de Espectroscopia Laser, Caracas (Venezuela); Lawrence Berkeley National laboratory, Berkeley, US (United States); Gonzalez, Jhanis; Xianglei, Mao; Russo, Richard [Lawrence Berkeley National laboratory, Berkeley, US (United States); Fernandez, Alberto [UCV- Laboratorio de Espectroscopia Laser, Caracas (Venezuela)
2008-04-15
The laser ablation has been increasing its popularity like as technique of chemical analysis. This is due to its great potentiality in the analysis of solid samples. On the way to contributing to the development of the technique, we in this work studied the laser induced breakdown spectroscopy (LIBS) in conditions of micro ablation for future studies of coverings and micro crates analysis. Craters between 2 and 7 micrometers of diameter were made using an Nd-YAG nanosecond laser in their fundamental emission of 1064 nm. In order to create these craters we use an objective lens of long distance work and 0.45 of numerical aperture. The atomic emission versus the energy of the laser and its effect on the size of craters was study. We found that below 3 micrometers although there was evidence of material removal by the formation of a crater, it was no detectable atomic emission for our instruments. In order to try to understand this, curves of size of crater versus plasma temperature using the Boltzmann distribution graphs taking the Copper emission lines in the visible region were made. In addition calibration curves for Copper and aluminum were made in two different matrices; one of it was a Cu/Zn alloy and the other a Zinc Matrix. The atomic lines Cu I (521.78 nm) and Al I (396.15 nm) was used. From the Calibration curve the analytical limit of detection and other analytical parameters were obtained.
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Searchlights Illuminate Apollo 8 on Pad 39-A
1968-01-01
Searchlights penetrate the darkness surrounding Apollo 8 on Pad 39-A at Kennedy Space Center. This mission was the first manned flight using the Saturn V. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.
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Apollo 6 Transported to Launch Pad at KSC
1968-01-01
Apollo 6, the second and last of the unmarned Saturn V test flights, is slowly transported past the Vehicle Assembly Building on the way to launch pad 39-A. The towering 363-foot Saturn V was a multi-stage, multi-engine launch vehicle standing taller than the Statue of Liberty. Altogether, the Saturn V engines produced as much power as 85 Hoover Dams.
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First-Time Analysis of Completely Restored DTREM Instrument Data from Apollo 14 and 15
McBride, Marie J.; Williams, David R.; Hills, H. Kent; Turner, Niescja
2013-01-01
The Dust, Thermal and Radiation Engineering Measurement (DTREM) packages (figure 1) mounted on the central stations of the Apollo 11, 12, 14, and 15 ALSEPs (Apollo Lunar Surface Experiments Packages) measured the outputs of exposed solar cells and thermistors over time. The goal of the experiment, also commonly known as the dust detector, was to study the long-term effects of dust, radiation, and temperature at the lunar surface on solar cells. The monitors returned data for up to almost 8 years from the lunar surface.
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Indigenous Carbonaceous Phases Embedded Within Surface Deposits on Apollo 17 Volcanic Glass Beads
Thomas-Keprta, K. L.; Clemett, S. J.; Ross, D. K.; Le, L.; McKay, D. S.; Gibson, E. K.; Gonzalez, C.
2012-01-01
The assessment of indigenous organic matter in returned lunar samples was one of the primary scientific goals of the Apollo program. Prior studies of Apollo samples have shown the total amount of organic matter to be in the range of approx 50 to 250 ppm. Low concentrations of lunar organics may be a consequence not only of its paucity but also its heterogeneous distribution. Several processes should have contributed to the lunar organic inventory including exogenous carbonaceous accretion from meteoroids and interplanetary dust particles, and endogenous synthesis driven by early planetary volcanism and cosmic and solar radiation.
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An anthropogenic origin of the "Sirente crater," Abruzzi, Italy
Speranza, Fabio; Sagnotti, Leonardo; Rochette, Pierre
2004-04-01
In this paper, we review the recent hypothesis, based mostly on geomorphological features, that a ~130 m-wide sag pond, surrounded by a saddle-shaped rim from the Sirente plain (Abruzzi, Italy), is the first-discovered meteoritic crater of Italy. Sub-circular depressions (hosting ponds), with geomorphological features and size very similar to those exhibited by the main Sirente sag, are exposed in other neighboring intermountain karstic plains from Abruzzi. We have sampled present day soils from these sag ponds and from the Sirente sags (both the main "crater" and some smaller ones, recently interpreted as a crater field) and various Abruzzi paleosols from excavated trenches with an age range encompassing the estimated age of the "Sirente crater." For all samples, we measured the magnetic susceptibility and determined the Ni and Cr contents of selected specimens. The results show that the magnetic susceptibility values and the geochemical composition are similar for all samples (from Sirente and other Abruzzi sags) and are both significantly different from the values reported for soils contaminated by meteoritic dust. No solid evidence pointing at an impact origin exists, besides the circular shape and rim of the main sag. The available observations and data suggest that the "Sirente crater," together with analogous large sags in the Abruzzi intermountain plains, have to be attributed to the historical phenomenon of "transumanza" (seasonal migration of sheep and shepherds), a custom that for centuries characterized the basic social-economical system of the Abruzzi region. Such sags were excavated to provide water for millions of sheep, which spent summers in the Abruzzi karstic high pasture lands, on carbonatic massifs deprived of natural superficial fresh water. Conversely, the distribution of the smaller sags from the Sirente plain correlates with the local pattern of the calcareous bedrock and, together with the characteristics of their internal structure, are
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Energy Technology Data Exchange (ETDEWEB)
Aggery, A
1999-12-01
The objective of this thesis is to add to the multigroup transport code APOLLO2 the capability to perform deterministic reference calculations, for any type of reactor, using a very fine energy mesh of several thousand groups. This new reference tool allows us to validate the self-shielding model used in industrial applications, to perform depletion calculations, differential effects calculations, critical buckling calculations or to evaluate precisely data required by the self shielding model. At its origin, APOLLO2 was designed to perform routine calculations with energy meshes around one hundred groups. That is why, in the current format of cross sections libraries, almost each value of the multigroup energy transfer matrix is stored. As this format is not convenient for a high number of groups (concerning memory size), we had to search out a new format for removal matrices and consequently to modify the code. In the new format we found, only some values of removal matrices are kept (these values depend on a reconstruction precision choice), the other ones being reconstructed by a linear interpolation, what reduces the size of these matrices. Then we had to show that APOLLO2 working with a fine multigroup mesh had the capability to perform reference calculations on any assembly geometry. For that, we successfully carried out the validation with several calculations for which we compared APOLLO2 results (obtained with the universal mesh of 11276 groups) to results obtained with Monte Carlo codes (MCNP, TRIPOLI4). Physical analysis led with this new tool have been very fruitful and show a great potential for such an R and D tool. (author)
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Fluids, evaporation and precipitates at Gale Crater
Schwenzer, S. P.; Bridges, J. C.; Leveille, R.; Wiens, R. C.; Mangold, N.; McAdam, A.; Conrad, P.; Kelley, S. P.; Westall, F.; Martín-Torres, F.; Zorzano, M.-P.
2015-01-01
The Mars Science Laboratory (MSL) mission landed in Gale Crater, Mars, on 6th August 2012, and has explored the Yellowknife Bay area. The detailed mineralogical and sedimentological studies provide a unique opportunity to characterise the secondary fluids associated with this habitable environment.
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Aqueous alteration detection in Tikhonravov crater, Mars
Mancarella, F.; Fonti, S.; Alemanno, G.; Orofino, V.; Blanco, A.
2018-03-01
The existence of a wet period lasting long enough to allow the development of elementary forms of life on Mars has always been a very interesting issue. Given this perspective, the research for geological markers of such occurrences has been continually pursued. Once a favorable site is detected, effort should be spent to get as much information as possible aimed at a precise assessment of the genesis and evolution of the areas showing the selected markers. In this work, we discuss the recent finding of possible deposits pointing to the past existence of liquid water in Tikhonravov crater located in Arabia Terra. Comparison of CRISM spectra and those of laboratory minerals formed by aqueous alteration has led us to the conclusion that the studied areas within the impact crater host phyllosilicates deposits. In addition, analysis of the CRISM spectra has resulted in the tentative identification of carbonates mixed with phyllosilicates.
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Assessment of Scheduling and Plan Execution of Apollo 14 Lunar Surface Operations
Marquez, Jessica J.
2010-01-01
Although over forty years have passed since first landing on the Moon, there is not yet a comprehensive, quantitative assessment of Apollo extravehicular activities (EVAs). Quantitatively evaluating lunar EVAs will provide a better understanding of the challenges involved with surface operations. This first evaluation of a surface EVA centers on comparing the planned and the as-ran timeline, specifically collecting data on discrepancies between durations that were estimated versus executed. Differences were summarized by task categories in order to gain insight as to the type of surface operation activities that were most challenging. One Apollo 14 EVA was assessed utilizing the described methodology. Selected metrics and task categorizations were effective, and limitations to this process were identified.
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The seismic expression and hydrocarbon potential of subsurface impact craters
Energy Technology Data Exchange (ETDEWEB)
Stewart, R.; Westbroek, H.H.; Lawton, D. [Calgary Univ., AB (Canada). Dept. of Geology and Geophysics
1995-12-31
The seismic characteristics of meteorite impact craters and their potential as oil and gas reservoirs were discussed. Seismic data from James River, Alberta, in the Western Canada Sedimentary Basin show subsurface anomalies to be meteorite impact structures. The White Valley structure in Saskatchewan has similar features and seismic anomalies indicate that it too could be a meteorite impact structure, although other possibilities have been proposed. Other impact structures in western Canada such as the Steen River structure and the Viewfield crater have or are producing hydrocarbons. 5 refs., 2 figs.
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Extreme Access & Lunar Ice Mining in Permanently Shadowed Craters Project
Mueller, Robert P.
2014-01-01
Results from the recent LCROSS mission in 2010, indicate that H2O ice and other useful volatiles such as CO, He, and N are present in the permanently shadowed craters at the poles of the moon. However, the extreme topography and steep slopes of the crater walls make access a significant challenge. In addition temperatures have been measured at 40K (-233 C) so quick access and exit is desirable before the mining robot cold soaks. The Global Exploration Roadmap lists extreme access as a necessary technology for Lunar Exploration.
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Computer simulation of explosion crater in dams with different buried depths of explosive
Zhang, Zhichao; Ye, Longzhen
2018-04-01
Based on multi-material ALE method, this paper conducted a computer simulation on the explosion crater in dams with different buried depths of explosive using LS-DYNA program. The results turn out that the crater size increases with the increase of buried depth of explosive at first, but closed explosion cavity rather than a visible crater is formed when the buried depth of explosive increases to some extent. The soil in the explosion cavity is taken away by the explosion products and the soil under the explosion cavity is compressed with its density increased. The research can provide some reference for the anti-explosion design of dams in the future.
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APOLLO 15 HEAT FLOW THERMAL CONDUCTIVITY RDR SUBSAMPLED V1.0
National Aeronautics and Space Administration — This data set comprises a reduced, subsampled set of the data returned from the Apollo 15 Heat Flow Experiment from 31 July 1971 through 31 December 1974. The...
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APOLLO 17 HEAT FLOW THERMAL CONDUCTIVITY RDR SUBSAMPLED V1.0
National Aeronautics and Space Administration — This data set comprises a reduced, subsampled set of the data returned from the Apollo 17 Heat Flow Experiment from 12 December 1972 through 31 December 1974. The...
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Apollo 10 astronauts in space suits in front of Command Module
1968-01-01
Three astronauts named as the prime crew of the Apollo 10 space mission. Left to right, are Eugene A. Cernan, lunar module pilot; John W. Young, command module pilot; and Thomas P. Stafford, commander.
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Ehlmann, Bethany L.; Swayze, Gregg A.; Milliken, Ralph E.; Mustard, John F.; Clark, Roger N.; Murchie, Scott L.; Breit, George N.; Wray, James J.; Gondet, Brigitte; Poulet, Francois; Carter, John; Calvin, Wendy M.; Benzel, William M.; Seelos, Kimberly D.
2016-01-01
Cross crater is a 65 km impact crater, located in the Noachian highlands of the Terra Sirenum region of Mars (30°S, 158°W), which hosts aluminum phyllosilicate deposits first detected by the Observatoire pour la Minéralogie, L’Eau, les Glaces et l’Activitié (OMEGA) imaging spectrometer on Mars Express. Using high-resolution data from the Mars Reconnaissance Orbiter, we examine Cross crater’s basin-filling sedimentary deposits. Visible/shortwave infrared (VSWIR) spectra from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) show absorptions diagnostic of alunite. Combining spectral data with high-resolution images, we map a large (10 km × 5 km) alunite-bearing deposit in southwest Cross crater, widespread kaolin-bearing sediments with variable amounts of alunite that are layered in <10 m scale beds, and silica- and/or montmorillonite-bearing deposits that occupy topographically lower, heavily fractured units. The secondary minerals are found at elevations ranging from 700 to 1550 m, forming a discontinuous ring along the crater wall beneath darker capping materials. The mineralogy inside Cross crater is different from that of the surrounding terrains and other martian basins, where Fe/Mg-phyllosilicates and Ca/Mg-sulfates are commonly found. Alunite in Cross crater indicates acidic, sulfurous waters at the time of its formation. Waters in Cross crater were likely supplied by regionally upwelling groundwaters as well as through an inlet valley from a small adjacent depression to the east, perhaps occasionally forming a lake or series of shallow playa lakes in the closed basin. Like nearby Columbus crater, Cross crater exhibits evidence for acid sulfate alteration, but the alteration in Cross is more extensive/complete. The large but localized occurrence of alunite suggests a localized, high-volume source of acidic waters or vapors, possibly supplied by sulfurous (H2S- and/or SO2-bearing) waters in contact with a magmatic source, upwelling
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Lunar and Planetary Science Conference, 20th, Houston, TX, Mar. 13-17, 1989, Proceedings
International Nuclear Information System (INIS)
Sharpton, V.L.; Ryder, G.
1990-01-01
Topics discussed include the petrology and geochemistry of the moon, the geology of the moon, lunar regolith processes and resources, the petrology and geochemistry of achondrites, comets and interplanetary dust, shock and terrestrial cratering, the geology of Mars, and the geology of Venus. Papers are presented on silicate liquid immiscibility in isothermal crystallization experiments; highly evolved and ultramafic lithologies from Apollo 14 soils; the relationship between orbital, earth-based, and sample data for lunar landing sites; and the volcanotectonic evolution of Mare Frigoris. Attention is also given to glass variants and multiple HASP trends in Apollo 14 regolith breccias, the characterization of lunar ilmenite resources, the U-Th-Pb systematics of the Estherville mesosiderite, and the extraterrestrial halogen and sulfur contents of the stratosphere. Other papers are on argon-40/argon-39 dating of impact craters; the outliers of dust along the southern margin of the Tharsis region, Mars; and the geology of southern Guinevere Planitia, Venus, based on analyses of Goldstone radar data
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On the crypto-explosive crater and its relation with gold mineralization in larma Au-U deposit
International Nuclear Information System (INIS)
Chen Guohua; Jing Hongxiang; Huang Shutao
1998-01-01
A new type of gold mineralization-controlling structure-hydrothermal crypto-explosive crater was identified at the Larma gold-uranium deposit in the border regions between Gansu and Sichuan provinces, western China. The hydrothermal crypto-explosive crater is ellipse-shaped at the surface, while funnel-like in profile. A silica-cap composed of hydrothermal siliceous breccia is distributed at the top of the crater, while hydrothermal crypto-explosive breccia are in the centre. The configuration of the crater is roughly consistent with the distribution of gold ore bodies. The formation mechanism of the crater is: first, a silica cap composed of hydrothermal siliceous metasomatic rock was formed at the contact area between the siliceous rock and the slate, and blocked the movement of hydrothermal fluid and resulted in the appearance of over-pressed geothermal environment. Then, at 49.5 Ma, the rejuvenation of the EW-striking faults in larma area resulted in the breaking of the brittle silica cap, followed by the crypto-explosion of hydrothermal fluid. In Larma gold-uranium deposit, the hydrothermal crypto-explosion gave rise to the precipitation of gold from the hydrothermal fluid, while the crypto-explosive crater provided the space for gold mineralization
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Impact-generated Hydrothermal Activity at the Chicxulub Crater
Kring, D. A.; Zurcher, L.; Abramov, O.
2007-05-01
Borehole samples recovered from PEMEX exploration boreholes and an ICDP scientific borehole indicate the Chicxulub impact event generated hydrothermal alteration throughout a large volume of the Maya Block beneath the crater floor and extending across the bulk of the ~180 km diameter crater. The first indications of hydrothermal alteration were observed in the crater discovery samples from the Yucatan-6 borehole and manifest itself in the form of anhydrite and quartz veins. Continuous core from the Yaxcopoil-1 borehole reveal a more complex and temporally extensive alteration sequence: following a brief period at high temperatures, impact- melt-bearing polymict breccias and a thin, underlying unit of impact melt were subjected to metasomatism, producing alkali feldspar, sphene, apatite, and magnetite. As the system continued to cool, smectite-series phyllosilicates appeared. A saline solution was involved. Stable isotopes suggest the fluid was dominated by a basinal brine created mostly from existing groundwater of the Yucatan Peninsula, although contributions from down-welling water also occurred in some parts of the system. Numerical modeling of the hydrothermal system suggests circulation occurred for 1.5 to 2.3 Myr, depending on the permeability of the system. Our understanding of the hydrothermal system, however, is still crude. Additional core recovery projects, particularly into the central melt sheet, are needed to better evaluate the extent and duration of hydrothermal alteration.
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Inclement Weather Crater Repair Tool Kit
2017-11-30
9. Corrugated steel quadcons. ....................................................................................................... 14 Figure 10...Saw cutting around crater upheaval. ERDC/GSL TR-17-26 6 The excavation team is responsible for breaking up the damaged portland cement ...in the table located on Sheet 2 in Appendix A. The corrugated steel quadcons (Item 1) are equipped with double swing doors on both ends of the
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Vivaldi, Valerio; Massironi, Matteo; Ninfo, Andrea; Cremonese, Gabriele
2015-04-01
In this study we have applied 3D morphometric analysis of impact craters on the Moon by means of high resolution DTMs derived from LROC (Lunar Reconnaissance Orbiter Camera) NAC (Narrow Angle Camera) (0.5 to 1.5 m/pixel). The objective is twofold: i) evaluating crater degradation and ii) exploring the potential of this approach for Maria stratigraphic interpretation. In relation to the first objective we have considered several craters with different diameters representative of the four classes of degradation being C1 the freshest and C4 the most degraded ones (Arthur et al., 1963; Wilhelms, 1987). DTMs of these craters were elaborated according to a multiscalar approach (Wood, 1996) by testing different ranges of kernel sizes (e.g. 15-35-50-75-100), in order to retrieve morphometric variables such as slope, curvatures and openness. In particular, curvatures were calculated along different planes (e.g. profile curvature and plan curvature) and used to characterize the different sectors of a crater (rim crest, floor, internal slope and related boundaries) enabling us to evaluate its degradation. The gradient of the internal slope of different craters representative of the four classes shows a decrease of the slope mean value from C1 to C4 in relation to crater age and diameter. Indeed degradation is influenced by gravitational processes (landslides, dry flows), as well as space weathering that induces both smoothing effects on the morphologies and infilling processes within the crater, with the main results of lowering and enlarging the rim crest, and shallowing the crater depth. As far as the stratigraphic application is concerned, morphometric analysis was applied to recognize morphologic features within some simple craters, in order to understand the stratigraphic relationships among different lava layers within Mare Serenitatis. A clear-cut rheological boundary at a depth of 200 m within the small fresh Linnè crater (diameter: 2.22 km), firstly hypothesized
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Control of the geomorphic evolution of an active crater: Popocatpetl (Mexico) 1994-2003.
Andrés, N.; Zamorano, J. J.; Palacios, D.; Macias, J. L.; Sanjosé, J. J.
2009-04-01
Volcanic activity often causes intense and successive geomorphic changes to occur inside a crater. In terms of hazard mitigation, it is important to understand the cause of these changes whether they be exterior lava spills, sequences of explosions or massive glacier melt. Access to an active crater, however, is very difficult and dangerous, so analytical approaches involving remote study must substitute actual fieldwork. Several studies done at Popocatepetl volcano during its most recent eruptive phase that began in December 1994, use remote techniques and are described in Cruz-Reyna et al. (1998), Wright et al. (2002), Martín-Del Pozo et al. (2003), Tanarro et al. (2005), Matiella et al. (2008), and Zamorano et al. (1996,1998), among others. The compendium of results reveals that recent volcanic activity on Popocatépetl is characterized by successive dome growth and destruction inside the crater. Macias and Siebe (2005) even suggest that the walls of the crater may no longer withstand future dome growth. The purpose of this study is to understand the morphologic evolution of the interior of the crater during the most active period of the present eruptive phase on Popocatepetl from 1994 to 2003. The methodology is based on photogrammetry techniques that have been used successfully at volcanic sites by Donnadieu et al. (2003), and on a GIS to organize information, draft maps and 3-D images, and to calculate spatial variations in landforms (Procter et al., 2006; Schilling et al., 2006). Traditional aerial photo interpretation was used for 22 triplets selected from a collection of photos taken by the Mexican Highway and Transport Secretariat, from 1982 to 2003, and enabled us to draft geomorphic maps of the interior of the crater. The photos and maps were rectified and georeferenced with ArcGis software, and then the maps were digitized. The areas containing morphologic units associated with a date (exterior crater walls, colluvial ramps and recent volcanic complex
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Connecting Returned Apollo Soils and Remote Sensing: Application to the Diviner Lunar Radiometer
Greenhagen, B. T.; DonaldsonHanna, K. L.; Thomas, I. R.; Bowles, N. E.; Allen, Carlton C.; Pieters, C. M.; Paige, D. A.
2014-01-01
The Diviner Lunar Radiometer, onboard NASA's Lunar Reconnaissance Orbiter, has produced the first global, high resolution, thermal infrared observations of an airless body. The Moon, which is the most accessible member of this most abundant class of solar system objects, is also the only body for which we have extraterrestrial samples with known spatial context, returned Apollo samples. Here we present the results of a comprehensive study to reproduce an accurate simulated lunar environment, evaluate the most appropriate sample and measurement conditions, collect thermal infrared spectra of a representative suite of Apollo soils, and correlate them with Diviner observations of the lunar surface. It has been established previously that thermal infrared spectra measured in simulated lunar environment (SLE) are significantly altered from spectra measured under terrestrial or martian conditions. The data presented here were collected at the University of Oxford Simulated Lunar Environment Chamber (SLEC). In SLEC, we simulate the lunar environment by: (1) pumping the chamber to vacuum pressures (less than 10-4 mbar) sufficient to simulate lunar heat transport processes within the sample, (2) cooling the chamber with liquid nitrogen to simulate radiation to the cold space environment, and (3) heating the samples with heaters and lamp to set-up thermal gradients similar to those experienced in the upper hundreds of microns of the lunar surface. We then conducted a comprehensive suite of experiments using different sample preparation and heating conditions on Apollo soils 15071 (maria) and 67701 (highland) and compared the results to Diviner noontime data to select the optimal experimental conditions. This study includes thermal infrared SLE measurements of 10084 (A11 - LM), 12001 (A12 - LM), 14259 (A14 - LM), 15071 (A15 - S1), 15601 (A15 - S9a), 61141 (A16 - S1), 66031 (A16 - S6), 67701 (A16 - S11), and 70181 (A17 - LM). The Diviner dataset includes all six Apollo sites
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1967-01-01
Immediately following the Apollo 204 accident of January 27, 1961. all associated equipment and material were impounded. Release of this equipment and material for normal use was under the close control of the Apollo 204 Review Board. Apollo Review Board Administrative Procedure No. 11, February 11, 1961, established the Apollo 204 Review Board Material Release Record (MRR). This MRR was the official form used to release material from full impoundment and was valid only after being approved by the Board and signed by a Member. The form was used as the authority to place any impounded item into one of the three Categories defined in Administrative Procedure No. 11. This appendix contains all of the authorized MRR's. Each item submitted on an MRR was given a control number; a description, including the part number and serial number; the relevance and location to the accident; any constraints before release; and the control category. The categories placed on the equipment were as follows: Category A - Items which may have a significant influence or bearing on the results or findings of the Apollo 204 Review Board; Category B - All material other than Category A which is considered relevant to the Apollo 204 Review Board investigation; Category C - Material released from Board jurisdiction. Several classes of equipment were released by special Board action prior to the establishment of the MRR system. The operating procedure for release of these classes is Enclosure F-l to this appendix.
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MSL Chemistry and Mineralogy X-Ray Diffraction X-Ray Fluorescence (CheMin) Instrument
Zimmerman, Wayne; Blake, Dave; Harris, William; Morookian, John Michael; Randall, Dave; Reder, Leonard J.; Sarrazin, Phillipe
2013-01-01
This paper provides an overview of the Mars Science Laboratory (MSL) Chemistry and Mineralogy Xray Diffraction (XRD), X-ray Fluorescence (XRF) (CheMin) Instrument, an element of the landed Curiosity rover payload, which landed on Mars in August of 2012. The scientific goal of the MSL mission is to explore and quantitatively assess regions in Gale Crater as a potential habitat for life - past or present. The CheMin instrument will receive Martian rock and soil samples from the MSL Sample Acquisition/Sample Processing and Handling (SA/SPaH) system, and process it utilizing X-Ray spectroscopy methods to determine mineral composition. The Chemin instrument will analyze Martian soil and rocks to enable scientists to investigate geophysical processes occurring on Mars. The CheMin science objectives and proposed surface operations are described along with the CheMin hardware with an emphasis on the system engineering challenges associated with developing such a complex instrument.
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Rescue and Preservation of Sample Data from the Apollo Missions to the Moon
Todd, Nancy S.; Zeigler, Ryan A.; Evans, Cindy A.; Lehnert, Kerstin
2016-01-01
Six Apollo missions landed on the Moon from 1969-72, returning to Earth 382 kg of lunar rock, soil, and core samples. These samples are among the best documented and preserved samples on Earth that have supported a robust research program for 45 years. From mission planning through sample collection, preliminary examination, and subsequent research, strict protocols and procedures are followed for handling and allocating Apollo subsamples, resulting in the production of vast amounts of documentation. Even today, hundreds of samples are allocated for research each year, building on the science foundation laid down by the early Apollo sample studies and combining new data from today's instrumentation, lunar remote sensing missions and lunar meteorites. Much sample information is available to researchers at curator.jsc.nasa.gov. Decades of analyses on lunar samples are published in LPSC proceedings volumes and other peer-reviewed journals, and tabulated in lunar sample compendia entries. However, for much of the 1969-1995 period, the processing documentation, individual and consortia analyses, and unpublished results exist only in analog forms or primitive digital formats that are either inaccessible or at risk of being lost forever because critical data from early investigators remain unpublished.
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Rapid sympatric ecological differentiation of crater lake cichlid fishes within historic times
Directory of Open Access Journals (Sweden)
Harrod Chris
2010-05-01
Full Text Available Abstract Background After a volcano erupts, a lake may form in the cooled crater and become an isolated aquatic ecosystem. This makes fishes in crater lakes informative for understanding sympatric evolution and ecological diversification in barren environments. From a geological and limnological perspective, such research offers insight about the process of crater lake ecosystem establishment and speciation. In the present study we use genetic and coalescence approaches to infer the colonization history of Midas cichlid fishes (Amphilophus cf. citrinellus that inhabit a very young crater lake in Nicaragua-the ca. 1800 year-old Lake Apoyeque. This lake holds two sympatric, endemic morphs of Midas cichlid: one with large, hypertrophied lips (~20% of the total population and another with thin lips. Here we test the associated ecological, morphological and genetic diversification of these two morphs and their potential to represent incipient speciation. Results Gene coalescence analyses [11 microsatellite loci and mitochondrial DNA (mtDNA sequences] suggest that crater lake Apoyeque was colonized in a single event from the large neighbouring great lake Managua only about 100 years ago. This founding in historic times is also reflected in the extremely low nuclear and mitochondrial genetic diversity in Apoyeque. We found that sympatric adult thin- and thick-lipped fishes occupy distinct ecological trophic niches. Diet, body shape, head width, pharyngeal jaw size and shape and stable isotope values all differ significantly between the two lip-morphs. The eco-morphological features pharyngeal jaw shape, body shape, stomach contents and stable isotopes (δ15N all show a bimodal distribution of traits, which is compatible with the expectations of an initial stage of ecological speciation under disruptive selection. Genetic differentiation between the thin- and thick-lipped population is weak at mtDNA sequence (FST = 0.018 and absent at nuclear
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Geological Structures in the WaIls of Vestan Craters
Mittlefehldt, David; Nathues, A.; Beck, A. W.; Hoffmann, M.; Schaefer, M.; Williams, D. A.
2014-01-01
A compelling case can be made that Vesta is the parent asteroid for the howardite, eucrite and diogenite (HED) meteorites [1], although this interpretation has been questioned [2]. Generalized models for the structure of the crust of Vesta have been developed based on petrologic studies of basaltic eucrites, cumulate eucrites and diogenites. These models use inferred cooling rates for different types of HEDs and compositional variations within the clan to posit that the lower crust is dominantly diogenitic in character, cumulate eucrites occur deep in the upper crust, and basaltic eucrites dominate the higher levels of the upper crust [3-5]. These models lack fine-scale resolution and thus do not allow for detailed predictions of crustal structure. Geophysical models predict dike and sill intrusions ought to be present, but their widths may be quite small [6]. The northern hemisphere of Vesta is heavily cratered, and the southern hemisphere is dominated by two 400-500 km diameter basins that excavated deep into the crust [7-8]. Physical modeling of regolith formation on 300 km diameter asteroids predicts that debris layers would reach a few km in thickness, while on asteroids of Vesta's diameter regolith thicknesses would be less [9]. This agrees well with the estimated =1 km thickness of local debris excavated by a 45 km diameter vestan crater [10]. Large craters and basins may have punched through the regolith/megaregolith and exposed primary vestan crustal structures. We will use Dawn Framing Camera (FC) [11] images and color ratio maps from the High Altitude and Low Altitude Mapping Orbits (HAMO, 65 m/pixel; LAMO, 20 m/pixel) to evaluate structures exposed on the walls of craters: two examples are discussed here.
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Basin Contributions to the Stratigraphy of the Apollo 16 Landing Site
Haskin, Larry A.
2001-01-01
Ejecta deposit modeling suggests that the megaregolith at the Apollo 16 landing site is dominated by Imbrium and Serenitatis ejecta, and Nectaris ejecta are a minor componen Additional information is contained in the original extended abstract.t.
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Matias, A.; Garvin, J. B.; Sakimoto, S. E. H.
1998-01-01
One intriguing aspect of martian impact crater morphology is the change of crater cavity and ejecta characteristics from the mid-latitudes to the polar regions. This is thought to reflect differences in target properties such as an increasing presence of ice in the polar regions. Previous image-based efforts concerning martian crater morphology has documented some aspects of this, but has been hampered by the lack of adequate topography data. Recent Mars Orbiter Laser Altimeter (MOLA) topographic profiles provide a quantitative perspective for interpreting the detailed morphologies of martian crater cavities and ejecta morphology. This study is a preliminary effort to quantify the latitude-dependent differences in morphology with the goal of identifying target-dependent and crater modification effects from the combined of images and MOLA topography. We combine the available MOLA profiles and the corresponding Viking Mars Digital Image Mosaics (MDIMS), and high resolution Viking Orbiter images to focus on two transitional craters; one on the mid-latitudes, and one in the North Polar region. One MOLA pass (MGS Orbit 34) traverses the center of a 15.9 km diameter fresh complex crater located at 12.8degN 83.8degE on the Hesperian ridge plains unit (Hvr). Viking images, as well as MOLA data, show that this crater has well developed wall terraces and a central peak with 429 m of relative relief. Three MOLA passes have been acquired for a second impact crater, which is located at 69.5degN 41degE on the Vastitas Borealis Formation. This fresh rampart crater lacks terraces and central peak structures and it has a depth af 579 m. Correlation between images and MOLA topographic profiles allows us to construct basic facies maps of the craters. Eight main units were identified, four of which are common on both craters.
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The Links Between Target Properties and Layered Ejecta Craters in Acidalia and Utopia Planitiae Mars
Jones, E.; Osinski, G. R.
2013-08-01
Layered ejecta craters on Mars may form from excavation into subsurface volatiles. We examine a new catalogue of martian craters to decipher differences between the single- and double-layered ejecta populations in Acidalia and Utopia.
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Layers of 'Cabo Frio' in 'Victoria Crater' (False Color)
2006-01-01
This view of 'Victoria crater' is looking southeast from 'Duck Bay' towards the dramatic promontory called 'Cabo Frio.' The small crater in the right foreground, informally known as 'Sputnik,' is about 20 meters (about 65 feet) away from the rover, the tip of the spectacular, layered, Cabo Frio promontory itself is about 200 meters (about 650 feet) away from the rover, and the exposed rock layers are about 15 meters (about 50 feet) tall. This is an enhanced false color rendering of images taken by the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity during the rover's 952nd sol, or Martian day, (Sept. 28, 2006) using the camera's 750-nanometer, 530-nanometer and 430-nanometer filters.
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Estimation of Apollo Lunar Dust Transport using Optical Extinction Measurements
Lane, John E.; Metzger, Philip T.
2015-04-01
A technique to estimate mass erosion rate of surface soil during landing of the Apollo Lunar Module (LM) and total mass ejected due to the rocket plume interaction is proposed and tested. The erosion rate is proportional to the product of the second moment of the lofted particle size distribution N(D), and third moment of the normalized soil size distribution S(D), divided by the integral of S(D)ṡD2/v(D), where D is particle diameter and v(D) is the vertical component of particle velocity. The second moment of N(D) is estimated by optical extinction analysis of the Apollo cockpit video. Because of the similarity between mass erosion rate of soil as measured by optical extinction and rainfall rate as measured by radar reflectivity, traditional NWS radar/rainfall correlation methodology can be applied to the lunar soil case where various S(D) models are assumed corresponding to specific lunar sites.
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Ups and downs in planetary science
Shoemaker, Carolyn S.
1999-01-01
The field of planetary science as it developed during the lifetimes of Gene and Carolyn Shoemaker has sustained a period of exciting growth. Surveying the skies for planet-crossing asteroids and comets and studying the results of their impact upon the planets, especially the Earth, was for Gene and Carolyn an intense and satisfying quest for knowledge. It all started when Gene envisioned man going to the Moon, especially himself. After that, one thing led to another: the study of nuclear craters and a comparison with Meteor Crater, Arizona; the Apollo project and a succession of unmanned space missions to the inner and outer planets; an awareness of cratering throughout our solar system; the search for near-Earth asteroids and comets; a study of ancient craters in Australia; and the impact of Shoemaker-Levy 9 on Jupiter. The new paradigm of impact cratering as a cause for mass extinction and the opening of space for the development of new life forms have been causes to champion.
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Portrait of Astronaut Neil A. Armstrong, commander of Apollo 11 mission
1969-01-01
Portrait of Astronaut Neil A. Armstrong, commander of the Apollo 11 Lunar Landing mission in his space suit, with his helmet on the table in front of him. Behind him is a large photograph of the lunar surface.
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Pina, P.; Marques, J. S.; Bandeira, L.
2013-12-01
The adaptive nature of automated crater detection algorithms permits achieving a high level of autonomous detections in different surfaces and consequently becoming an important tool in the update of crater catalogues. Nevertheless, the available approaches assume all craters as circular and only provide as output the radius and location of each crater. However, the delineation of impact craters following the local variability of the rims is also important to, among others, evaluate their degree of degradation or preservation, namely those studies related to ancient climate analysis. This contour determination is normally prepared in a manual way but can advantageously be done by image analysis methods, eliminating subjectivity and allowing large scale delineations. We have recently proposed a pair of independent approaches to tackle with this problem, one based on processing the crater image in polar coordinates [1], the other using morphological operators [2], which achieved a good degree of success on very high resolution images from Mars [3-4], but where enough room for improvement was still available. Thus, the integration of both approaches into a single one, suppressing the individual drawbacks of the previous approaches, permitted to strength the detection procedure. We describe now the novel sequence of processing that we have built and test it intensively in a wider variety of planetary surfaces, namely, those of Mars, Mercury and the Moon, using the very high resolution images provided by HiRISE, MDIS and LROC cameras. The automated delineations of the craters are compared to a ground-truth reference (manually delineated contours), so a quantitative evaluation can be performed; on a dataset constituted by more than one thousand impact craters we have obtained a global high delineation rate. The breakdown by crater size on each surface is performed. The whole processing procedure works on raster images and also delivers the output in the same image format
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APOLLO: a quality assessment service for single and multiple protein models.
Wang, Zheng; Eickholt, Jesse; Cheng, Jianlin
2011-06-15
We built a web server named APOLLO, which can evaluate the absolute global and local qualities of a single protein model using machine learning methods or the global and local qualities of a pool of models using a pair-wise comparison approach. Based on our evaluations on 107 CASP9 (Critical Assessment of Techniques for Protein Structure Prediction) targets, the predicted quality scores generated from our machine learning and pair-wise methods have an average per-target correlation of 0.671 and 0.917, respectively, with the true model quality scores. Based on our test on 92 CASP9 targets, our predicted absolute local qualities have an average difference of 2.60 Å with the actual distances to native structure. http://sysbio.rnet.missouri.edu/apollo/. Single and pair-wise global quality assessment software is also available at the site.
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Rice, Melissa S.; Gupta, Sanjeev; Bell, James F., III; Warner, Nicholas H.
2011-01-01
Eberswalde crater was selected as a candidate landing site for the Mars Science Laboratory (MSL) mission based on the presence of a fan-shaped sedimentary deposit interpreted as a delta. We have identified and mapped five other candidate fluvio -deltaic systems in the crater, using images and digital terrain models (DTMs) derived from the Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE) and Context Camera (CTX). All of these systems consist of the same three stratigraphic units: (1) an upper layered unit, conformable with (2) a subpolygonally fractured unit, unconformably overlying (3) a pitted unit. We have also mapped a system of NNE-trending scarps interpreted as dip-slip faults that pre-date the fluvial -lacustrine deposits. The post-impact regional faulting may have generated the large-scale topography within the crater, which consists of a Western Basin, an Eastern Basin, and a central high. This topography subsequently provided depositional sinks for sediment entering the crater and controlled the geomorphic pattern of delta development.
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Sonder, I.; Graettinger, A. H.; Valentine, G.; Schmid, A.; Zimanowski, B.; Majji, M.; Ross, P.; White, J. D.; Taddeucci, J.; Lube, G.; Kueppers, U.; Bowman, D. C.
2013-12-01
In an ongoing effort to understand the relevant processes behind the formation of volcanic crater-, maar-, and diatreme structures, experiments producing craters with radii exceeding one meter were conducted at University at Buffalos Geohazards Field Station. A chemical explosive was used as energy source for the tests, and detonated in prepared test beds made from several stratified, compacted aggregates. The amount of explosive, as well as its depth of burial were varied in the twelve experiments. The detonations were recorded by a diverse set of sensors including high-speed/high-definition cameras, seismic and electric field sensors, normal- and infrasound microphones. Morphology and structures were documented after each blast by manual measurements and semi-automated photogrammetry. After all blasts were complete the structures excavated and analyzed. The measured sensor signals were evaluated and related to blast energies, depths of burial and crater morphologies. Former experiments e.g. performed by Goto et al. (2001; Geophys. Res. Lett. 28, 4287-4290) considered craters of single blasts at a given lateral position and found empirical relationships emphasizing the importance of length scaling with the cube root of the blasts energy E. For example the depth of burial producing the largest crater radius--the ';optimal' depth--is proportional to E1/3, as is the corresponding radius. Resembling natural processes creating crater and diatreme structures the experiments performed here feature several blasts at one lateral position. The dependencies on E1/3 could be roughly confirmed. Also the scaled depth correlated with the sensor signals capturing the blasts dynamics. However, significant scatter was introduced by the pre-existing morphologies. Using a suitable re-definition for the charges depth of burial (';eruption depth'), accounting for a pre-existing (crater) morphology, the measured dependencies of morphology and blast dynamics on E can be improved
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Design development of the Apollo command and service module thrust vector attitude control systems
Peters, W. H.
1978-01-01
Development of the Apollo thrust vector control digital autopilot (TVC DAP) was summarized. This is the control system that provided pitch and yaw attitude control during velocity change maneuvers using the main rocket engine on the Apollo service module. A list of ten primary functional requirements for this control system are presented, each being subordinate to a more general requirement appearing earlier on the list. Development process functions were then identified and the essential information flow paths were explored. This provided some visibility into the particular NASA/contractor interface, as well as relationships between the many individual activities.
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The Context of Carbonates in Gusev and Jezero Craters
Ruff, S. W.; Hamilton, V. E.
2017-12-01
Gusev and Jezero are Noachian-aged craters with evidence of a lake in early Mars history. Both are among three remaining candidates for the Mars 2020 rover mission, which is intended to collect and cache rock samples for possible future return to Earth. Gusev was explored by the Spirit rover from 2004 to 2010, revealing outcrops dubbed Comanche composed of olivine-rich volcanic tephra that hosts up to 30% Mg-Fe carbonate, clear evidence for the role of near-neutral pH fluids [1]. Jezero also displays evidence for olivine- and carbonate-bearing materials, likely Mg-carbonate based on orbital spectral observations [2]. In both craters, the carbonates occur in materials that are among the oldest stratigraphic units in each, perhaps an indication of more clement climatic conditions on early Mars compared to those that prevailed for most of its history. We are undertaking investigations of various rover-based and orbital measurements of the carbonates in Gusev to better understand their geologic context and origin. In doing so, the results shed light on carbonate occurrences in Jezero. The Comanche outcrops are contained in the Columbia Hills, which represent a kipuka or island of eroded older terrain fully encircled by lava flows, here with a crater retention age of 3.65 Ga (Fig. 1). In situ and orbital observations [3] demonstrate that carbonate-bearing outcrops extend beyond those visited by Spirit. The distinctive morphology and thermal inertia signature of these outcrops and their unaltered host rocks are recognizable in other kipukas on the floor of Gusev [4]. Carbonate also occurs in kipukas in Jezero (Fig. 2), but larger occurrences extend beyond the crater rim and in isolated places among the delta fan deposits [2]. The presence of carbonates outside of the crater suggests an origin unrelated to a former lake, unlike the Comanche carbonates, which may have arisen through evaporation of dilute brines from an ephemeral lake in Gusev [4]. In both cases, the clear
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Geochemistry of Lunar Highland Meteorites Mil, 090034, 090036 AND 090070
Shirai, N.aoki; Ebihara, M.; Sekimoto, S.; Yamaguchi, A.; Nyquist, L.; Shih, C.-Y.; Park, J.; Nagao, K.
2012-01-01
Apollo and Luna samples were collected from a restricted area on the near side of the Moon, while the source craters of the lunar meteorites are randomly distributed. For example, Takeda et al. [1] and Yamaguchi et al. [2] found a variety of lithic clasts in Dho 489 and Y 86032 which were not represented by Apollo samples, and some of these clasts have lower rare earth elements (REE) and FeO abundances than Apollo anorthosites, respectively. Takeda et al. [1] and Yamaguchi et al. [2] concluded that Dho 489 and Y 86032 originated from the lunar farside. Therefore, lunar meteorites provide an opportunity to study lunar surface rocks from areas not sampled by Apollo and Luna missions. Three lunar anorthitic breccias (MIL 090034, 090036 and 090070) were found on the Miller Range Ice Field in Antarctica during the 2009-2010 ANSMET season [3]. In this study, we determined elemental abudnances for MIL 090034, 090036 and 090070 by using INAA and aimed to characterize these meteorites in chemical compositions in comparison with those for other lunar meteorites and Apollo samples.
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RCRA Part A permit characterization plan for the U-2bu subsidence crater. Revision 1
International Nuclear Information System (INIS)
1998-04-01
This plan presents the characterization strategy for Corrective Action Unit (CAU) 109, U-2bu Subsidence Crater (referred to as U-2bu) in Area 2 at the Nevada Test Site (NTS). The objective of the planned activities is to obtain sufficient characterization data for the crater soils and observed wastes under the conditions of the current Resource Conservation and Recovery Act (RCRA) Part A permit. The scope of the characterization plan includes collecting surface and subsurface soil samples with hand augers and for the purpose of site characterization. The sampling strategy is to characterize the study area soils and look for RCRA constituents. Observable waste soils and surrounding crater soils will be analyzed and evaluated according to RCRA closure criteria. Because of the status of the crater a RCRA Part A permit site, acquired radionuclide analyses will only be evaluated in regards to the health and safety of site workers and the disposition of wastes generated during site characterization. The U-2bu Subsidence Crater was created in 1971 by a Lawrence Livermore National Laboratory underground nuclear test, event name Miniata, and was used as a land-disposal unit for radioactive and hazardous waste from 1973 to 1988
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Lunar heat flow: Regional prospective of the Apollo landing sites
Siegler, M. A.; Smrekar, S. E.
2014-01-01
reexamine the Apollo Heat Flow Experiment in light of new orbital data. Using three-dimensional thermal conduction models, we examine effects of crustal thickness, density, and radiogenic abundance on measured heat flow values at the Apollo 15 and 17 sites. These models show the importance of regional context on heat flux measurements. We find that measured heat flux can be greatly altered by deep subsurface radiogenic content and crustal density. However, total crustal thickness and the presence of a near-surface radiogenic-rich ejecta provide less leverage, representing only minor (<1.5 mW m-2) perturbations on surface heat flux. Using models of the crust implied by Gravity Recovery and Interior Laboratory results, we found that a roughly 9-13 mW m-2 mantle heat flux best approximate the observed heat flux. This equates to a total mantle heat production of 2.8-4.1 × 1011 W. These heat flow values could imply that the lunar interior is slightly less radiogenic than the Earth's mantle, perhaps implying that a considerable fraction of terrestrial mantle material was incorporated at the time of formation. These results may also imply that heat flux at the crust-mantle boundary beneath the Procellarum potassium, rare earth element, and phosphorus (KREEP) Terrane (PKT) is anomalously elevated compared to the rest of the Moon. These results also suggest that a limited KREEP-rich layer exists beneath the PKT crust. If a subcrustal KREEP-rich layer extends below the Apollo 17 landing site, required mantle heat flux can drop to roughly 7 mW m-2, underlining the need for future heat flux measurements outside of the radiogenic-rich PKT region.
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X-Ray Diffraction on Mars: Scientific Discoveries Made by the CheMin Instrument
Rampe, E. B.; Blake, D. F.; Ming, D. W.; Bristow, T. F.
2017-01-01
The Mars Science Laboratory Curiosity landed in Gale crater in August 2012 with the goal to identify and characterize habitable environments on Mars. Curiosity has been studying a series of sedimentary rocks primarily deposited in fluviolacustrine environments approximately 3.5 Ga. Minerals in the rocks and soils on Mars can help place further constraints on these ancient aqueous environments, including pH, salinity, and relative duration of liquid water. The Chemistry and Mineralogy (CheMin) X-ray diffraction and X-ray fluorescence instrument on Curiosity uses a Co X-ray source and charge-coupled device detector in transmission geometry to collect 2D Debye-Scherrer ring patterns of the less than 150 micron size fraction of drilled rock powders or scooped sediments. With an angular range of approximately 2.52deg 20 and a 20 resolution of approximately 0.3deg, mineral abundances can be quantified with a detection limit of approximately 1-2 wt. %. CheMin has returned quantitative mineral abundances from 16 mudstone, sandstone, and aeolian sand samples so far. The mineralogy of these samples is incredibly diverse, suggesting a variety of depositional and diagenetic environments and different source regions for the sediments. Results from CheMin have been essential for reconstructing the geologic history of Gale crater and addressing the question of habitability on ancient Mars.
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International Nuclear Information System (INIS)
Susiati, Heni; Sjarmufni, A.; S.B.S, Yarianto; Suprijadi; Wibagyo
2001-01-01
Community surrounding the Asembagus Sugar Fabric guess that the factory has polluted water body of Banyuputih River. Leakage detection of the pollutant has been to prove that guess using variation of natural isotop composition of Deuterium and Oxygen-18. Sampling was carried out at Ijen crater area, Banyupahit River and surrounding the sugar factory and also Belawan Fresh water source. Isotop analysis was done-by mass spectrometer. Based on analysis result have been gotten information that each location have vary of isotop value, Isotop concentration at Ijen crater was relative high so isotop concentration of Banyupahit river was also relative high although rather lower than lien Crater. Based on another interpretation, there are correlation at isotope concentration between Ijen crater and Banyupahit River
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Beaulieu, K. R.; Blumenfeld, E. H.; Liddle, D. A.; Oshel, E. R.; Evans, C. A.; Zeigler, R. A.; Righter, K.; Hanna, R. D.; Ketcham, R. A.
2017-01-01
Our team is developing a modern, cross-disciplinary approach to documentation and preservation of astromaterials, specifically lunar and meteorite samples stored at the Johnson Space Center (JSC) Lunar Sample Laboratory Facility. Apollo Lunar Sample 60639, collected as part of rake sample 60610 during the 3rd Extra-Vehicular Activity of the Apollo 16 mission in 1972, served as the first NASA-preserved lunar sample to be examined by our team in the development of a novel approach to internal and external sample visualization. Apollo Sample 60639 is classified as a breccia with a glass-coated side and pristine mare basalt and anorthosite clasts. The aim was to accurately register a 3-dimensional Micro X-Ray Computed Tomography (XCT)-derived internal composition data set and a Structure-From-Motion (SFM) Photogrammetry-derived high-fidelity, textured external polygonal model of Apollo Sample 60639. The developed process provided the means for accurate, comprehensive, non-destructive visualization of NASA's heritage lunar samples. The data products, to be ultimately served via an end-user web interface, will allow researchers and the public to interact with the unique heritage samples, providing a platform to "slice through" a photo-realistic rendering of a sample to analyze both its external visual and internal composition simultaneously.
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PUBLIC AFFAIRS DIRECTOR HUGH HARRIS SPEAKS AT THE APOLLO/SATURN V CENTER RIBBON-CUTTING CEREMONY
1996-01-01
NASA/KSC Public Affairs Director Hugh W. Harris gives the welcome and introductions at the ribbon-cutting ceremony to officially open the new Apollo/Saturn V Center, part of the Kennedy Space Center Visitor Center. The 100,000- square-foot facility includes two theaters, various exhibits and an Apollo-era Saturn V rocket, which formerly was on display outside the Vehicle Assembly Building and is one of only three moon rockets remaining in existence. The new center is located off the Kennedy Parkway at the Banana Creek launch viewing site.
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The Apollo Number: space suits, self-support, and the walk-run transition.
Directory of Open Access Journals (Sweden)
Christopher E Carr
Full Text Available BACKGROUND: How space suits affect the preferred walk-run transition is an open question with relevance to human biomechanics and planetary extravehicular activity. Walking and running energetics differ; in reduced gravity (<0.5 g, running, unlike on Earth, uses less energy per distance than walking. METHODOLOGY/PRINCIPAL FINDINGS: The walk-run transition (denoted * correlates with the Froude Number (Fr = v(2/gL, velocity v, gravitational acceleration g, leg length L. Human unsuited Fr* is relatively constant (approximately 0.5 with gravity but increases substantially with decreasing gravity below approximately 0.4 g, rising to 0.9 in 1/6 g; space suits appear to lower Fr*. Because of pressure forces, space suits partially (1 g or completely (lunar-g support their own weight. We define the Apollo Number (Ap = Fr/M as an expected invariant of locomotion under manipulations of M, the ratio of human-supported to total transported mass. We hypothesize that for lunar suited conditions Ap* but not Fr* will be near 0.9, because the Apollo Number captures the effect of space suit self-support. We used the Apollo Lunar Surface Journal and other sources to identify 38 gait events during lunar exploration for which we could determine gait type (walk/lope/run and calculate Ap. We estimated the binary transition between walk/lope (0 and run (1, yielding Fr* (0.36+/-0.11, mean+/-95% CI and Ap* (0.68+/-0.20. CONCLUSIONS/SIGNIFICANCE: The Apollo Number explains 60% of the difference between suited and unsuited Fr*, appears to capture in large part the effects of space suits on the walk-run transition, and provides several testable predictions for space suit locomotion and, of increasing relevance here on Earth, exoskeleton locomotion. The knowledge of how space suits affect gait transitions can be used to optimize space suits for use on the Moon and Mars.
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Potential Cement Phases in Sedimentary Rocks Drilled by Curiosity at Gale Crater, Mars
Rampe, E. B.; Morris, R. V.; Bish, D. L.; Chipera, S. J.; Ming, D. W.; Blake, D. F.; Vaniman, D. T.; Bristow, T. F.; Cavanagh, P.; Farmer, J. D.;
2015-01-01
The Mars Science Laboratory rover Curiosity has encountered a variety of sedimentary rocks in Gale crater with different grain sizes, diagenetic features, sedimentary structures, and varying degrees of resistance to erosion. Curiosity has drilled three rocks to date and has analyzed the mineralogy, chemical composition, and textures of the samples with the science payload. The drilled rocks are the Sheepbed mudstone at Yellowknife Bay on the plains of Gale crater (John Klein and Cumberland targets), the Dillinger sandstone at the Kimberley on the plains of Gale crater (Windjana target), and a sedimentary unit in the Pahrump Hills in the lowermost rocks at the base of Mt. Sharp (Confidence Hills target). CheMin is the Xray diffractometer on Curiosity, and its data are used to identify and determine the abundance of mineral phases. Secondary phases can tell us about aqueous alteration processes and, thus, can help to elucidate past aqueous environments. Here, we present the secondary mineralogy of the rocks drilled to date as seen by CheMin and discuss past aqueous environments in Gale crater, the potential cementing agents in each rock, and how amorphous materials may play a role in cementing the sediments.
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Okubo, C. H.; Schultz, R. A.; Nahm, A. L.
2007-07-01
The strength and deformability of light-toned layered deposits are estimated based on measurements of porosity from Microscopic Imager data acquired by MER Opportunity during its traverse from Eagle Crater to Erebus Crater.
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Visibility of lunar surface features - Apollo 14 orbital observations and lunar landing.
Ziedman, K.
1972-01-01
Description of an in-flight visibility test conducted during the Apollo 14 mission for the purpose of validating and extending the mathematical visibility models used previously in the course of the Apollo program to examine the constraints on descent operations imposed by lunar visibility limitations. Following a background review of the effects on mission planning of the visibility limitations due to downsun lunar surface detail 'washout' and a discussion of the visibility prediction techniques previously used for studying lunar visibility problems, the visibility test rationale and procedures are defined and the test results presented. The results appear to confirm the validity of the visibility prediction techniques employed in lunar visibility problem studies. These results provide also a basis for improving the accuracy of the prediction techniques by appropriate modifications.
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Vesicles in Apollo 15 Green Glasses: The Nature of Ancient Lunar Gases
Thomas-Keprta, K. L.; Clemett, S. J.; Berger, E. L.; Rahman, Z.; McKay, D. S.; Gibson, E. K.; Wentworth, S. J.
2014-01-01
Detailed studies of Apollo 15 green glass and related beads have shown they were formed in gas-rich fire fountains.. As the magmatic fluid became super-saturated in volatile gas, bubbles or vesicles formed within the magma. These exsolved gases became trapped within vesicles as the glasses were ejected from the fire-fountain and subsequently quenched. One of the keys to understanding formation processes on the ancient moon includes determining the composition of volatile species and elements, including metals, dissolved in magmatic gases. Here we report the nature of mineral phases spatially associated with vesicles in a green glass bead from Apollo sample 15411,42. The phases reflect the composition of the cooling/degassing magmatic vapors and fluids present at the time of bead formation approx, 3 Ga ago
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Apollo - An advanced fuel fusion power reactor for the 21st century
International Nuclear Information System (INIS)
Kulcinski, G.L.; Emmert, G.A.; Blanchard, J.P.
1989-01-01
A preconceptual design of a tokamak reactor fueled by a D-He-3 plasma is presented. A low aspect ratio (A=2-4) device is studied here but high aspect ratio devices (A > 6) may also be quite attractive. The Apollo D-He-3 tokamak capitalizes on recent advances in high field magnets (20 T) and utilizes rectennas to convert the synchrotron radiation directly to electricity. The overall efficiency ranges from 37 to 52% depending on whether the bremsstrahlung energy is utilized. The low neutron wall loading (0.1 MW/m/sup 2/) allows a permanent first wall to be designed and the low nuclear decay heat enables the reactor to be classed as inherently safe. The cost of electricity from Apollo is > 40% lower than electricity from a similar sized DT reactor
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Effects of Apollo 12 lunar material on lipid levels of tobacco tissue and slash pine cultures
Weete, J. D.
1972-01-01
Investigations of the lipid components of pine tissues (Pinus elloitii) are discussed, emphasizing fatty acids and steroids. The response by slash pine tissue cultures to growth in contact with Apollo lunar soil, earth basalt, and Iowa soil is studied. Tissue cultures of tobacco grown for 12 weeks in contact with lunar material from Apollo 12 flight contained 21 to 35 percent more total pigment than control tissues. No differences were noted in the fresh or dry weight of the experimental and control samples.
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Complex explosive volcanic activity on the Moon within Oppenheimer crater, Icarus
Bennett, Kristen A; Horgan, Briony H N; Gaddis, Lisa R.; Greenhagen, Benjamin T; Allen, Carlton C.; Hayne, Paul O; Bell, James F III; Paige, David A.
2016-01-01
Oppenheimer Crater is a floor-fractured crater located within the South Pole-Aitken basin on the Moon, and exhibits more than a dozen localized pyroclastic deposits associated with the fractures. Localized pyroclastic volcanism on the Moon is thought to form as a result of intermittently explosive Vulcanian eruptions under low effusion rates, in contrast to the higher-effusion rate, Hawaiian-style fire fountaining inferred to form larger regional deposits. We use Lunar Reconnaissance Orbiter Camera images and Diviner Radiometer mid-infrared data, Chandrayaan-1 orbiter Moon Mineralogy Mapper near-infrared spectra, and Clementine orbiter Ultraviolet/Visible camera images to test the hypothesis that the pyroclastic deposits in Oppenheimer crater were emplaced via Vulcanian activity by constraining their composition and mineralogy. Mineralogically, we find that the deposits are variable mixtures of orthopyroxene and minor clinopyroxene sourced from the crater floor, juvenile clinopyroxene, and juvenile iron-rich glass, and that the mineralogy of the pyroclastics varies both across the Oppenheimer deposits as a whole and within individual deposits. We observe similar variability in the inferred iron content of pyroclastic glasses, and note in particular that the northwest deposit, associated with Oppenheimer U crater, contains the most iron-rich volcanic glass thus far identified on the Moon, which could be a useful future resource. We propose that this variability in mineralogy indicates variability in eruption style, and that it cannot be explained by a simple Vulcanian eruption. A Vulcanian eruption should cause significant country rock to be incorporated into the pyroclastic deposit; however, large areas within many of the deposits exhibit spectra consistent with high abundances of juvenile phases and very little floor material. Thus, we propose that at least the most recent portion of these deposits must have erupted via a Strombolian or more continuous fire
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Mercatali, A.
2018-01-01
On 1st March 2012 an observative session of Moon's Plato crater was made. The purpose of these observations was to check the presence of one shadow with "hook" form at the inner of Plato crater already reported by H. Percy Wilkins, 3th April 21:30 UT, 1952. The results obtained by us have not shown any shadow with an hook form, but a shadow like a shark fin.
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Evidence for a meteoritic origin of the September 15, 2007, Carancas crater
Le Pichon, A.; Antier, K.; Cansi, Y.; Hernandez, B.; Minaya, E.; Burgoa, B.; Drob, D.; Evers, L. G.; Vaubaillon, J.
2008-01-01
On September 15th, 2007, around 11:45 local time in Peru, near the Bolivian border, the atmospheric entry of a meteoroid produced bright lights in the sky and intense detonations. Soon after, a crater was discovered south of Lake Titicaca. These events have been detected by the Bolivian seismic network and two infrasound arrays operating for the Comprehensive Nuclear-Test-Ban Treaty Organization, situated at about 80 and 1620 km from the crater. The localization and origin time ...
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2011-01-01
Abstract Highlights ?We present an in-depth study of Copernicus crater. ? First publication based on new NIR data from the SIR-2 mission to the Moon. ? New NIR spectral classification of surface materials within the crater. ? Highly detailed mapping of spectrally-prominent mineral species. Abstract Newly acquired, sequentially spaced, high resolution near-infrared spectra across the central section of crater Copernicus? interior have been analysed using a r...
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Dapremont. A.; Allen, C.; Runyon, C.
2014-01-01
Gale is a Late Noachian/Early Hesperian impact crater located on the dichotomy boundary separating the southern highlands and the northern lowlands of Mars. NASA's Curiosity Rover is currently exploring Gale, searching for evidence of habitability early in Mars history. With an approximate diameter of 155 km, and a approx. 5 km central mound informally titled Mt. Sharp, Gale represents a region of geologic interest due to the abundance of knowledge that can be derived, through its sedimentary deposits, pertaining to the environmental evolution of Mars. This study was undertaken to compare wind erosional features in Gale Crater and within sediments in a 1000 km radial area. The ultimate objective of this comparison was to determine if or how Gale relates to the surrounding region.
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Energy Technology Data Exchange (ETDEWEB)
Hughes, S.S.; Schmitt, R.A.; (Oregon State Univ., Corvallis (USA)); Delano, J.W. (State Univ. of New York, Albany (USA))
1988-10-01
Apollo 15 yellow-brown glass is one of twenty-five, high Mg, primary magmas emplaced on the lunar surface in pyroclastic eruptions. Forty spherules of this glass were individually analyzed by electron microprobe and INAA for major- and trace-elements. The abundances demonstrate that this primary magma was produced by partial melting of differentiated cumulates in the lunar mantle. Models are developed to explain the possible source-regions of several Apollo 15 and Apollo 12 low-Ti mare magmas as being products of hybridization involving three ancient differentiated components of a primordial lunar magma ocean: (a) early olivine {plus minus} orthopyroxene cumulates; (b) late-stage clinopyroxene + pigeonite + ilmenite + plagioclase cumulates; and (c) late-stage inter-cumulus liquid.
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Diagenetic silica enrichment and late-stage groundwater activity in Gale crater, Mars
Frydenvang, Jens; Gasda, Patrick J.; Hurowitz, Joel A.; Grotzinger, John P.; Wiens, Roger C.; Newsom, Horton E.; Edgett, Ken S.; Watkins, Jessica; Bridges, John C.; Maurice, Sylvestre; Fisk, Martin R.; Johnson, Jeffrey R.; Rapin, William; Stein, Nathan; Clegg, Sam M.; Schwenzer, S. P.; Bedford, C.; Edwards, P.; Mangold, Nicolas; Cousin, Agnes; Anderson, Ryan; Payre, Valerie; Vaniman, David; Blake, David; Lanza, Nina L.; Gupta, Sanjeev; Van Beek, Jason; Sautter, Violaine; Meslin, Pierre-Yves; Rice, Melissa; Milliken, Ralf; Gellert, Ralf; Thompson, Lucy; Clark, Ben C.; Sumner, Dawn Y.; Fraeman, Abigail A.; Kinch, Kjartan M; Madsen, Morten B.; Mitofranov, Igor; Jun, Insoo; Calef, Fred J.; Vasavada, Ashwin R.
2017-01-01
Diagenetic silica enrichment in fracture-associated halos that crosscut lacustrine and unconformably overlying aeolian sedimentary bedrock is observed on the lower north slope of Aeolis Mons in Gale crater, Mars. The diagenetic silica enrichment is colocated with detrital silica enrichment observed in the lacustrine bedrock yet extends into a considerably younger, unconformably draping aeolian sandstone, implying that diagenetic silica enrichment postdates the detrital silica enrichment. A causal connection between the detrital and diagenetic silica enrichment implies that water was present in the subsurface of Gale crater long after deposition of the lacustrine sediments and that it mobilized detrital amorphous silica and precipitated it along fractures in the overlying bedrock. Although absolute timing is uncertain, the observed diagenesis likely represents some of the most recent groundwater activity in Gale crater and suggests that the timescale of potential habitability extended considerably beyond the time that the lacustrine sediments of Aeolis Mons were deposited.
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Landscape evolution on Mars - A model of aeolian denudation in Gale Crater
Day, M. D.; Kocurek, G.; Grotzinger, J. P.
2015-12-01
Aeolian erosion has been the dominant geomorphic agent to shape the surface of Mars for the past ~3.5 billion years. Although individual geomorphic features evidencing aeolian activity are well understood (e.g., yardangs, dune fields, and wind streaks), landscapes formed by aeolian erosion remain poorly characterized. Intra-crater sedimentary mounds are hypothesized to have formed by wind deflation of craters once filled with flat-lying strata, and, therefore, should be surrounded by landscapes formed by aeolian erosion. Here we present a landscape evolution model that provides both an initial characterization of aeolian landscapes, and a mechanism for large-scale excavation. Wind excavation of Gale Crater to form the 5 km high Mount Sharp would require removal of 6.4 x 104 km3 of sediment. Imagery in Gale Crater from satellites and the Mars Science Laboratory rover Curiosity shows a surface characterized by first-cycle aeolian erosion of bedrock. The overall landscape is interpreted to represent stages in a cycle of aeolian deflation and excavation, enhanced by physical weathering (e.g., thermal fracturing, cratering). Initial wind erosion of bedrock is enhanced along fractures, producing retreating scarps. Underlying less resistant layers then erode faster than the armoring cap rock, increasing relief in scarps to form retreating mesas. As scarp retreat continues, boulders from the armoring cap unit break away and cover the hillslopes of less resistant material below the scarps. Eventually all material from the capping unit is eroded away and a boulder-capped hill remains. Winnowing of fine material flattens hillslope topography, leaving behind a desert pavement. Over long enough time, this pavement is breached and the cycle begins anew. This cycle of landscape denudation by the wind is similar to that of water, but lacks characteristic subaqueous features such as dendritic drainage networks.