[ { "id": "authors:2t82j-9d912", "collection": "authors", "collection_id": "2t82j-9d912", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170213-092643097", "type": "article", "title": "Can space exploration survive the end of the Cold War?", "author": [ { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" } ], "abstract": "The first, heroic age of space exploration was driven by national rivalry between the USA and USSR. There have indeed been recent achievements, but as the Cold War ends the superpowers are turning their attention to domestic Issues and the prospect looms of a prolonged hiatus In apace exploration. The only way forward Is through International cooperation, but this will never happen without a serious Investment of political will. A well-planned, long-term strategy for the exploration of Mars could provide the necessary focus.", "doi": "10.1016/j.spacepol.2016.12.003", "issn": "0265-9646", "publisher": "Elsevier", "publication": "Space Policy", "publication_date": "2016-08", "series_number": "3", "volume": "37", "issue": "3", "pages": "184-189" }, { "id": "authors:d4acs-jm175", "collection": "authors", "collection_id": "d4acs-jm175", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20101105-105009225", "type": "article", "title": "Diviner Lunar Radiometer Observations of Cold Traps in the Moon's South Polar Region", "author": [ { "family_name": "Paige", "given_name": "David A.", "clpid": "Paige-D-A" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "Diviner Lunar Radiometer Experiment surface-temperature maps reveal the existence of widespread surface and near-surface cryogenic regions that extend beyond the boundaries of persistent shadow. The Lunar Crater Observation and Sensing Satellite (LCROSS) struck one of the coldest of these regions, where subsurface temperatures are estimated to be 38 kelvin. Large areas of the lunar polar regions are currently cold enough to cold-trap water ice as well as a range of both more volatile and less volatile species. The diverse mixture of water and high-volatility compounds detected in the LCROSS ejecta plume is strong evidence for the impact delivery and cold-trapping of volatiles derived from primitive outer solar system bodies.", "doi": "10.1126/science.1187726", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2010-10-22", "series_number": "6003", "volume": "330", "issue": "6003", "pages": "479-482" }, { "id": "authors:b4r0f-5d998", "collection": "authors", "collection_id": "b4r0f-5d998", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20100920-095907719", "type": "article", "title": "Crater population and resurfacing of the Martian north polar layered deposits", "author": [ { "family_name": "Banks", "given_name": "Maria E.", "clpid": "Banks-M-E" }, { "family_name": "Byrne", "given_name": "Shane", "clpid": "Byrne-S" }, { "family_name": "Galla", "given_name": "Kapil", "clpid": "Galla-K" }, { "family_name": "McEwen", "given_name": "Alfred S.", "clpid": "McEwen-A-S" }, { "family_name": "Bray", "given_name": "Veronica J.", "clpid": "Bray-V-J" }, { "family_name": "Dundas", "given_name": "Colin M.", "clpid": "Dundas-C-M" }, { "family_name": "Fishbaugh", "given_name": "Kathryn E.", "clpid": "Fishbaugh-K-E" }, { "family_name": "Herkenhoff", "given_name": "Kenneth E.", "orcid": "0000-0002-3153-6663", "clpid": "Herkenhoff-K-E" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "Present-day accumulation in the north polar layered deposits (NPLD) is thought to occur via deposition on the north polar residual cap. Understanding current mass balance in relation to current climate would provide insight into the climatic record of the NPLD. To constrain processes and rates of NPLD resurfacing, a search for craters was conducted using images from the Mars Reconnaissance Orbiter Context Camera. One hundred thirty craters have been identified on the NPLD, 95 of which are located within a region defined to represent recent accumulation. High Resolution Imaging Science Experiment images of craters in this region reveal a morphological sequence of crater degradation that provides a qualitative understanding of processes involved in crater removal. A classification system for these craters was developed based on the amount of apparent degradation and infilling and where possible depth/diameter ratios were determined. The temporal and spatial distribution of crater degradation is interpreted to be close to uniform. Through comparison of the size-frequency distribution of these craters with the expected production function, the craters are interpreted to be an equilibrium population with a crater of diameter D meters having a lifetime of ~30.75D^(1.14) years. Accumulation rates within these craters are estimated at 7.2D^(\u22120.14) mm/yr, which corresponds to values of ~3\u20134 mm/yr and are much higher than rates thought to apply to the surrounding flat terrain. The current crater population is estimated to have accumulated in the last ~20 kyr or less.", "doi": "10.1029/2009JE003523", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "2010-08-28", "series_number": "8", "volume": "115", "issue": "8", "pages": "Art. No. E08006" }, { "id": "authors:86rbd-2dg57", "collection": "authors", "collection_id": "86rbd-2dg57", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131125-133402209", "type": "article", "title": "The Lunar Reconnaissance Orbiter Diviner Lunar Radiometer Experiment", "author": [ { "family_name": "Paige", "given_name": "D. A.", "clpid": "Paige-D-A" }, { "family_name": "Foote", "given_name": "M. C.", "clpid": "Foote-M-C" }, { "family_name": "Greenhagen", "given_name": "B. T.", "clpid": "Greenhagen-B-T" }, { "family_name": "Schofield", "given_name": "J. T.", "clpid": "Schofield-J-T" }, { "family_name": "Calcutt", "given_name": "S.", "clpid": "Calcutt-S" }, { "family_name": "Vasavada", "given_name": "A. R.", "orcid": "0000-0003-2665-286X", "clpid": "Vasavada-A-R" }, { "family_name": "Preston", "given_name": "D. J.", "clpid": "Preston-D-J" }, { "family_name": "Taylor", "given_name": "F. W.", "clpid": "Taylor-F-W" }, { "family_name": "Allen", "given_name": "C. C.", "clpid": "Allen-C-C" }, { "family_name": "Snook", "given_name": "K. J.", "clpid": "Snook-K-J" }, { "family_name": "Jakosky", "given_name": "B. M.", "clpid": "Jakosky-B-M" }, { "family_name": "Murray", "given_name": "B. C.", "clpid": "Murray-B-C" }, { "family_name": "Soderblom", "given_name": "L. A.", "orcid": "0000-0002-0917-853X", "clpid": "Soderblom-L-A" }, { "family_name": "Jau", "given_name": "B.", "clpid": "Jau-B" }, { "family_name": "Loring", "given_name": "S.", "clpid": "Loring-S" }, { "family_name": "Bulharowski", "given_name": "J.", "clpid": "Bulharowski-J" }, { "family_name": "Bowles", "given_name": "N. E.", "clpid": "Bowles-N-E" }, { "family_name": "Thomas", "given_name": "I. R.", "clpid": "Thomas-I-R" }, { "family_name": "Sullivan", "given_name": "M. T.", "clpid": "Sullivan-M-T" }, { "family_name": "Avis", "given_name": "C.", "clpid": "Avis-C" }, { "family_name": "De Jong", "given_name": "E. M.", "clpid": "De-Jong-E-M" }, { "family_name": "Hartford", "given_name": "W.", "clpid": "Hartford-W" }, { "family_name": "McCleese", "given_name": "D. J.", "clpid": "McCleese-D-J" } ], "abstract": "The Diviner Lunar Radiometer Experiment on NASA's Lunar Reconnaissance Orbiter will be the first instrument to systematically map the global thermal state of the Moon and its diurnal and seasonal variability. Diviner will measure reflected solar and emitted infrared radiation in nine spectral channels with wavelengths ranging from 0.3 to 400 microns. The resulting measurements will enable characterization of the lunar thermal environment, mapping surface properties such as thermal inertia, rock abundance and silicate mineralogy, and determination of the locations and temperatures of volatile cold traps in the lunar polar regions.", "doi": "10.1007/s11214-009-9529-2", "issn": "0038-6308", "publisher": "Springer", "publication": "Space Science Reviews", "publication_date": "2010-01", "series_number": "1-4", "volume": "150", "issue": "1-4", "pages": "125-160" }, { "id": "authors:kjgvt-8jw50", "collection": "authors", "collection_id": "kjgvt-8jw50", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-152845292", "type": "article", "title": "Evidence for ice flow prior to trough formation in the martian north polar layered deposits", "author": [ { "family_name": "Winebrenner", "given_name": "Dale P.", "clpid": "Winebrenner-D-P" }, { "family_name": "Koutnik", "given_name": "Michelle R.", "clpid": "Koutnik-M-R" }, { "family_name": "Waddington", "given_name": "Edwin D.", "clpid": "Waddington-E-D" }, { "family_name": "Pathare", "given_name": "Asmin V.", "clpid": "Pathare-A-V" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Byrne", "given_name": "Shane", "clpid": "Byrne-S" }, { "family_name": "Bamber", "given_name": "Jonathan L.", "clpid": "Bamber-J-L" } ], "abstract": "The relative importance of surface mass fluxes and ice flow in shaping the north polar layered deposits (NPLD), now or in the past, remains a fundamental and open question. Motivated by observation of an apparent ice divide on Gemina Lingula (also known as Titania Lobe), we propose a two-stage evolution leading to the present-day topography on that lobe of the NPLD. Ice flow approximately balances surface mass fluxes in the first stage, but in the second stage ice flow has minimal influence and topography is modified predominantly by the formation of troughs. We focus here on evidence for the first stage, by testing the fit of topography between troughs to an ice-flow model. We find that independent model fits on distinct flow paths closely match inter-trough topography, uniformly over a broad region on Gemina Lingula, with mutually consistent and physically reasonable fitting parameters. However, our model requires ice to occupy and flow in spaces where troughs currently incise the ice. We therefore infer that the troughs (and the distribution of mass balance that caused them) post-date deposition of the inter-trough material and its modification by flow. Because trough formation has apparently altered inter-trough topography very little, we infer that trough formation must have been rapid in comparison to the (still unknown) time-scale of flow since troughs began to form. We view the evidence for past flow as strong, but we do not think that topographic evidence alone can be conclusive. Observations of englacial stratigraphy using orbital sounding radars will yield conclusive tests of our inferred mechanism for the formation of inter-trough topography.", "doi": "10.1016/j.icarus.2007.11.030", "issn": "0019-1035", "publisher": "Elsevier", "publication": "Icarus", "publication_date": "2008-05", "series_number": "1", "volume": "195", "issue": "1", "pages": "90-105" }, { "id": "authors:r8k9n-zww83", "collection": "authors", "collection_id": "r8k9n-zww83", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-151420396", "type": "article", "title": "Eolian controlled modification of the martian south polar layered deposits", "author": [ { "family_name": "Koutnik", "given_name": "Michelle R.", "clpid": "Koutnik-M-R" }, { "family_name": "Byrne", "given_name": "Shane", "clpid": "Byrne-S" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Toigo", "given_name": "Anthony D.", "clpid": "Toigo-A-D" }, { "family_name": "Crawford", "given_name": "Zane A.", "clpid": "Crawford-Z-A" } ], "abstract": "Data from the Mars Orbiter Laser Altimeter (MOLA) and Mars Orbiter Camera (MOC) aboard the Mars Global Surveyor (MGS) mission and the Thermal Emission Imaging System (THEMIS) aboard the Mars Odyssey mission have revealed unique surface features in a particular region of the South Polar Layered Deposits (SPLD). The dominant morphology is large-scale quasi-parallel grooves that extend for hundreds of kilometers with only tens of meters of vertical relief, that we have termed here the \"Wire Brush\" terrain. The grooves are also transected by disjointed, yet roughly continuous, low-relief sinuous ridges that cross roughly perpendicular to the trend-direction of the large-scale grooves and show only tens of meters of relief. We interpret these ridges to be eroded remnants of folded layers. At the northern end of the large-scale grooves there are non-symmetric mounds. They are frequently preceded by a significant depression and/or trailing grooves that are parallel to the Wire Brush trend. We find that a two-stage process involving winds that intermittently remove a low-density crust exposing the underlying ice to ablation is the interpretation that best explains the multitude of features observed here. These features appear to be currently inactive indicating higher winds in previous epochs.", "doi": "10.1016/j.icarus.2004.09.015", "issn": "0019-1035", "publisher": "Elsevier", "publication": "Icarus", "publication_date": "2005-04", "series_number": "2", "volume": "174", "issue": "2", "pages": "490-501" }, { "id": "authors:xjc36-n9t24", "collection": "authors", "collection_id": "xjc36-n9t24", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140414-132022144", "type": "article", "title": "Modification of secondary craters on the Martian South Polar Layered Deposits", "author": [ { "family_name": "Schaller", "given_name": "E. L.", "clpid": "Schaller-E-L" }, { "family_name": "Murray", "given_name": "B.", "clpid": "Murray-B-C" }, { "family_name": "Pathare", "given_name": "A. V.", "clpid": "Pathare-A-V" }, { "family_name": "Rasmussen", "given_name": "J.", "clpid": "Rasmussen-J" }, { "family_name": "Byrne", "given_name": "S.", "clpid": "Byrne-S" } ], "abstract": "Secondary crater fields are important stratigraphic markers that can shed light on resurfacing processes that have occurred since their formation. We examine the morphologies of secondary craters formed from the ejection of material from two large impacts on the Martian South Polar Layered Deposits (SPLD): McMurdo crater at 84.5\u00b0S, 0\u00b0W, and an unnamed impact at 80.8\u00b0S, 284\u00b0W. The morphologies of these secondary craters allow us to impose constraints on the modification history of the SPLD. We have quantified crater morphologies using data sets from the Mars Global Surveyor and Mars Odyssey missions. We find a complete lack of secondary craters smaller than 300 m in diameter in both crater fields, which implies that at least the upper 30 m of the deposits have been resurfaced since the time of these impacts. Secondary crater depth-to-diameter ratios are low (average of 0.016), indicating that significant degradation has occurred since their emplacement. We find that vertical resurfacing alone is not enough to explain the observed depth-to-diameter distribution and suggest that viscous relaxation of craters coupled with a small amount of vertical resurfacing best fits the data. In the McMurdo field, high depth-to-diameter craters are found preferentially on steeper terrain associated with scarps cutting through the secondary field. This observation suggests that crater modification exhibits a dependence on slope. We comment on possible mechanisms that may explain this observation. The morphologies of secondary craters on the SPLD point to modification processes without lunar parallel and not yet fully modeled for Mars.", "doi": "10.1029/2004JE002334", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "2005-02-15", "series_number": "E2", "volume": "110", "issue": "E2", "pages": "Art. No. E02004" }, { "id": "authors:wy857-4t385", "collection": "authors", "collection_id": "wy857-4t385", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-142758244", "type": "article", "title": "South Polar Layered Deposits of Mars: The cratering record", "author": [ { "family_name": "Koutnik", "given_name": "Michelle", "clpid": "Koutnik-M" }, { "family_name": "Byrne", "given_name": "Shane", "clpid": "Byrne-S" }, { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" } ], "abstract": "Data from the Mars Orbiter Laser Altimeter (MOLA) and Mars Orbiter Camera (MOC) instruments aboard the Mars Global Surveyor (MGS) were used in a detailed search of a selected part of the South Polar Layered Deposits (SPLD) for impact craters. Impact craters with diameters from 0.8 to 5 km were identified from a MOLA-derived shaded relief map and were primarily validated using individual MOLA tracks and, in select cases, MOC narrow angle images. The resultant crater population determined in this study is at least four times the density of the crater population previously recognized. From these new statistics, we estimate the mean apparent surface age of the SPLD to be 30\u2013100 Ma, depending on the established production model isochrons used. All of these craters are considerably shallower than other Martian craters in the same diameter range. We attribute this shallowness to be the cause of the lower detection rates of previous studies. There is a correlation between crater depth and rim height, which suggests that both erosion and infilling have affected the crater forms. A similar study of the north polar layered deposits uncovered no craters in this diameter range. A limited population of craters smaller than 800 m was uncovered in higher-resolution MOC narrow angle images. These do not appear to have been degraded to the same degree. This separate population implies a surface exposure age of only 100,000 years and perhaps indicates an event that erased all small craters and degraded and infilled the larger ones.", "doi": "10.1029/2001JE001805", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "2002-11", "series_number": "E11", "volume": "107", "issue": "E11", "pages": "Art. No. 5100" }, { "id": "authors:4rsmh-4eq90", "collection": "authors", "collection_id": "4rsmh-4eq90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141029-144250693", "type": "article", "title": "North polar stratigraphy and the paleo-erg of Mars", "author": [ { "family_name": "Byrne", "given_name": "Shane", "orcid": "0000-0002-6735-4685", "clpid": "Byrne-S" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "An accurate self-consistent way of coregistering the imaging and topographic data sets of the Mars Global Surveyor mission was developed and used to begin a stratigraphic analysis of the northern polar region. A distinct change in the layering style exists at a definite stratigraphic horizon near the base of the north polar layered deposits. Occurrences of the contact between two distinct layered units can be mapped hundreds of kilometers apart at nearly the same Mars Orbiter Laser Altimeter (MOLA) elevation. The lower layered unit has a consistent association with sand dunes, leading to the conclusion that it is an eroding sand-rich deposit that predates most of the overlying north polar layered deposits, which exhibits the expected features of a dust-ice mixture. These results suggest that an areally extensive erg was in existence before the present ice cap and that the present circumpolar erg is likely composed of material reworked from this older deposit. The volume of this lower unit is estimated to be on the order of 10^5 km^3. The presence of this deposit implies that there existed a period in Mars' history when there was no icy polar cap. A dramatic climatic change leading to the deposition of the upper layered (icy) unit in the present-day polar layered deposits represents a major event in Mars' history. However, owing to uncertainties in the mechanics of layered deposits formation, such an event cannot be dated at this time.", "doi": "10.1029/2001JE001615", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "2002-06", "series_number": "E6", "volume": "107", "issue": "E6", "pages": "Art. No. 5044" }, { "id": "authors:dmk63-txw74", "collection": "authors", "collection_id": "dmk63-txw74", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141029-145036052", "type": "article", "title": "Merton Davies (1917-2001)", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "Merton Davies passed away unexpectedly in\nApril at age 83 due to complications from\nsurgery. He will be remembered for establishing\nthe prime meridian for essentially every solid\nplanet in the solar system with the exception of\nEarth and Pluto. He was an AGU Fellow, and had\nbeen a member since 1970 (Planetary Sciences).", "doi": "10.1029/01EO00323", "issn": "0096-3941", "publisher": "American Geophysical Union", "publication": "Eos", "publication_date": "2001-11-13", "series_number": "46", "volume": "82", "issue": "46", "pages": "551" }, { "id": "authors:b8mc8-32y13", "collection": "authors", "collection_id": "b8mc8-32y13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131211-152152382", "type": "article", "title": "Preliminary Geological Assessment of the Northern Edge of Ultimi Lobe, Mars South Polar Layered Deposits", "author": [ { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" }, { "family_name": "Koutnik", "given_name": "Michelle", "clpid": "Koutnik-M" }, { "family_name": "Byrne", "given_name": "Shane", "clpid": "Byrne-S" }, { "family_name": "Soderblom", "given_name": "Laurence", "orcid": "0000-0002-0917-853X", "clpid": "Soderblom-L-A" }, { "family_name": "Herkenhoff", "given_name": "Kenneth", "orcid": "0000-0002-3153-6663", "clpid": "Herkenhoff-K-E" }, { "family_name": "Tanaka", "given_name": "Kenneth L.", "clpid": "Tanaka-Kenneth-L" } ], "abstract": "We have examined the local base of the south polar layered deposits (SPLD) exposed in the bounding scarp near 72\u00b0\u201374\u00b0S, 215\u00b0\u2013230\u00b0W where there is a clear unconformable contact with older units. Sections of layering up to a kilometer thick were examined along the bounding scarp, permitting an estimate of the thinnest individual layers yet reported in the SPLD. Rhythmic layering is also present locally, suggesting a similarly rhythmic variation in environmental conditions and a recorded climate signal at least in some SPLD strata. Locally, angular unconformities may be present, as has been reported for the north polar layered deposits (NPLD) and may likewise imply intervals of subaerial erosion in the SPLD. The outcropping layers display a broad range of weathering styles and may reflect more diverse conditions of depositions, erosion, and diagenesis than might have been expected from simple aeolian depostion modulated only by astronomically driven climatic fluctuations.\n\nAn unexpected finding of our study is the presence of locally abundant small pits close to the bounding scarp. These quasi-circular, negative, rimless features probably originated as impact craters and were modified to varying degrees by local endogenic processes, as well as locally variable blanketing. A nominal exposure age for the most heavily cratered region in our study area is about 2 million years, and the crater statistics appear consistent with those for the overall SPLD, although there are large uncertainties in the absolute ages implied by the crater size\u2013frequency statistics, as in all martian crater ages.\n\nAnother new finding is the presence of mass wasting features along the steepest portion of the retreating bounding scarp as well as a number of examples of brittle fracture, consistent with large-scale slumping along the bounding scarp and probably also ancient basal sliding. Both subhorizontal and high angle faults appear to be exposed in the bounding scarp, but the dips of the faults are poorly constrained. These fractures, along with the relatively undeformed layers between them, suggest to us that whatever horizontal motion may have taken place outward from the central cap region was accomplished by ancient basal sliding rather than large-scale glacial-like flow or ice migration by differential ablation, as proposed recently for the northern permanent cap and underlying NPLD. We have also obtained the first direct estimate of the regional dip of the SPLD, around 2\u20133\u00b0 outward (northward) in one area.", "doi": "10.1006/icar.2001.6657", "issn": "0019-1035", "publisher": "Elsevier", "publication": "Icarus", "publication_date": "2001-11", "series_number": "1", "volume": "154", "issue": "1", "pages": "80-97" }, { "id": "authors:emtqj-neq08", "collection": "authors", "collection_id": "emtqj-neq08", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-163214214", "type": "article", "title": "Practical limits on hyperspectral vegetation discrimination in arid and semiarid environments", "author": [ { "family_name": "Okin", "given_name": "Gregory S.", "clpid": "Okin-G-S" }, { "family_name": "Roberts", "given_name": "Dar A.", "clpid": "Roberts-D-A" }, { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" }, { "family_name": "Okin", "given_name": "William J.", "clpid": "Okin-W-J" } ], "abstract": "Hyperspectral remote sensing is a promising tool for the analysis of vegetation and soils in remote sensing imagery. The purpose of this study is to ascertain how well hyperspectral remote sensing data can retrieve vegetation cover, vegetation type, and soil type in areas of low vegetation cover. We use multiple endmember spectral mixture analysis (MESMA), high-quality field spectra, and AVIRIS data to determine how well full-range spectral mixture analysis (SMA) techniques can retrieve vegetation and soil information. Using simulated AVIRIS-derived reflectance spectra, we find that, in areas of low vegetation cover, MESMA is not able to provide reliable retrievals of vegetation type when covers are less than at least 30%. Overestimations of vegetation are likely, but vegetation cover in many circumstances can be estimated reliably. Soil type retrievals are more than 90% reliable in discriminating dark-armored desert soils from blown sands. This simulation comprises a best-case scenario in which many typical problems with remote sensing in areas of low cover or desert areas are minimized. Our results have broad implications for the applicability of full-range SMA techniques in analysis of data from current and planned hyperspectral sensors. Several phenomena contribute to the unreliability of vegetation retrievals. Spectrally indeterminate vegetation types, characterized by low spectral contrast, are difficult to model correctly even at relatively high covers. Combinations of soil and vegetation spectra have the potential of generating mixtures that resemble an unmixed spectrum from different material, further confounding vegetation cover and soil type retrievals. Intraspecies spectral variability and nonlinear mixing produce uncertainties in spectral endmembers much larger than that only due to instrumental noise modeled here. Having established limits on linear spectral unmixing in areas of low cover through spectral simulations, we evaluate AVIRIS-derived reflectance data from the Mojave Desert, California. We show that MESMA is capable of mapping soil surface types even when vegetation type cannot be reasonable retrieved.", "doi": "10.1016/S0034-4257(01)00207-3", "issn": "0034-4257", "publisher": "Elsevier", "publication": "Remote Sensing of Environment", "publication_date": "2001-08", "series_number": "2", "volume": "77", "issue": "2", "pages": "212-225" }, { "id": "authors:zd6nd-rx506", "collection": "authors", "collection_id": "zd6nd-rx506", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140415-085909528", "type": "article", "title": "Evidence That the Reactivity of the Martian Soil Is Due to\n Superoxide Ions", "author": [ { "family_name": "Yen", "given_name": "A. S.", "clpid": "Yen-A-S" }, { "family_name": "Kim", "given_name": "S. S.", "clpid": "Kim-S-S" }, { "family_name": "Hecht", "given_name": "M. H.", "clpid": "Hecht-M-H" }, { "family_name": "Frant", "given_name": "M. S.", "clpid": "Frant-M-S" }, { "family_name": "Murray", "given_name": "B.", "clpid": "Murray-B-C" } ], "abstract": "The Viking Landers were unable to detect evidence of life on Mars but, instead, found a chemically reactive soil capable of decomposing organic molecules. This reactivity was attributed to the presence of one or more as-yet-unidentified inorganic superoxides or peroxides in the martian soil. Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O_(2)\u2013) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.", "doi": "10.1126/science.289.5486.1909", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2000-09-15", "series_number": "5486", "volume": "289", "issue": "5486", "pages": "1909-1912" }, { "id": "authors:yzzgg-7e959", "collection": "authors", "collection_id": "yzzgg-7e959", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130124-090538648", "type": "article", "title": "The State and Future of Mars Polar Science and Exploration", "author": [ { "family_name": "Clifford", "given_name": "Stephen M.", "clpid": "Clifford-S-M" }, { "family_name": "Ingersoll", "given_name": "Andy P.", "orcid": "0000-0002-2035-9198", "clpid": "Ingersoll-A-P" }, { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" } ], "abstract": "As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of \u223c10^6 km^2 and total as much as 3\u20134 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young\u2014preserving a record of the seasonal and climatic cycling of atmospheric CO_2, H_2O, and dust over the past \u223c10^5\u201310^8 years. For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet\u2014documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life. Beyond their scientific value, the polar regions may soon prove important for another reason\u2014providing a valuable and accessible reservoir of water to support the long-term human exploration of Mars. In this paper we assess the current state of Mars polar research, identify the key questions that motivate the exploration of the polar regions, discuss the extent to which current missions will address these questions, and speculate about what additional capabilities and investigations may be required to address the issues that remain outstanding.", "doi": "10.1006/icar.1999.6290", "issn": "0019-1035", "publisher": "Elsevier", "publication": "Icarus", "publication_date": "2000-04", "series_number": "2", "volume": "144", "issue": "2", "pages": "210-242" }, { "id": "authors:t03zf-zks28", "collection": "authors", "collection_id": "t03zf-zks28", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140522-101619178", "type": "article", "title": "Surface properties of Mars' polar layered deposits and polar landing sites", "author": [ { "family_name": "Vasavada", "given_name": "Ashwin R.", "orcid": "0000-0003-2665-286X", "clpid": "Vasavada-A-R" }, { "family_name": "Williams", "given_name": "Jean-Pierre", "orcid": "0000-0001-5058-695X", "clpid": "Williams-J-P" }, { "family_name": "Paige", "given_name": "David A.", "clpid": "Paige-D-A" }, { "family_name": "Herkenhoff", "given_name": "Ken E.", "orcid": "0000-0002-3153-6663", "clpid": "Herkenhoff-K-E" }, { "family_name": "Bridges", "given_name": "Nathan T.", "orcid": "0000-0002-6790-6793", "clpid": "Bridges-N-T" }, { "family_name": "Greeley", "given_name": "Ronald", "clpid": "Greeley-R" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Bass", "given_name": "Deborah S.", "clpid": "Bass-D-S" }, { "family_name": "McBride", "given_name": "Karen S.", "clpid": "McBride-K-S" } ], "abstract": "On December 3, 1999, the Mars Polar Lander and Mars Microprobes will land on the planet's south polar layered deposits near (76\u00b0S, 195\u00b0W) and conduct the first in situ studies of the planet's polar regions. The scientific goals of these missions address several poorly understood and globally significant issues, such as polar meteorology, the composition and volatile content of the layered deposits, the erosional state and mass balance of their surface, their possible relationship to climate cycles, and the nature of bright and dark aeolian material. Derived thermal inertias of the southern layered deposits are very low (50\u2013100 J m^(\u22122) s^(\u22121/2) K^(\u22121)), suggesting that the surface down to a depth of a few centimeters is generally fine grained or porous and free of an appreciable amount of rock or ice. The landing site region is smoother than typical cratered terrain on \u223c1 km pixel^(\u22121) Viking Orbiter images but contains low-relief texture on \u223c5 to 100 m pixel^(\u22121) Mariner 9 and Mars Global Surveyor images. The surface of the southern deposits is older than that of the northern deposits and appears to be modified by aeolian erosion or ablation of ground ice.", "doi": "10.1029/1999JE001108", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "2000-03-25", "series_number": "E3", "volume": "105", "issue": "E3", "pages": "6961-6969" }, { "id": "authors:edcgn-7nk88", "collection": "authors", "collection_id": "edcgn-7nk88", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130415-152214853", "type": "article", "title": "Stability of hydroxylated minerals on Mars: A study on the effects of exposure to ultraviolet radiation", "author": [ { "family_name": "Yen", "given_name": "Albert S.", "clpid": "Yen-A-S" }, { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" }, { "family_name": "Rossman", "given_name": "George R.", "orcid": "0000-0002-4571-6884", "clpid": "Rossman-G-R" }, { "family_name": "Grunthaner", "given_name": "Frank J.", "clpid": "Grunthaner-F-J" } ], "abstract": "The density and composition of the Martian atmosphere allow solar ultraviolet photons with wavelengths as short as 190 nm to reach the surface. We investigate the hypothesis that this UV radiation is capable of inducing the release of water from iron oxyhydroxide minerals resulting in the formation of oxide phases. These experiments, which utilize a quadrupole mass spectrometer to monitor the water vapor pressure above mineral samples during cyclic exposure to ultraviolet radiation, offer 5 to 6 orders of magnitude greater sensitivity than previous attempts to establish and quantify this process. We find no evidence that UV photons are capable of liberating OH from the crystal lattice of minerals, and we set a minimum ultraviolet radiation-induced dehydroxylation time of 10^8 years for removal of this structural OH from mineral particles at the Martian surface. The overturning timescales for surface fines are likely to be shorter than this lower limit for exposure time. Thus we conclude that UV-stimulated dehydroxylation is not a significant process at the Martian surface and that iron oxyhydroxides, if formed during an earlier water-rich environment, should still be found on Mars today. The lack of clear evidence for iron oxyhydroxides at the Martian surface further suggests that Mars' surface was never warm and wet for a long enough period of time for Earth-like weathering to have occurred.", "doi": "10.1029/1999JE001065", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "1999-11-25", "series_number": "E11", "volume": "104", "issue": "E11", "pages": "27031-27041" }, { "id": "authors:d7w39-63n81", "collection": "authors", "collection_id": "d7w39-63n81", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140416-103953096", "type": "article", "title": "Deep Space 2: The Mars Microprobe Mission", "author": [ { "family_name": "Smrekar", "given_name": "Suzanne", "clpid": "Smrekar-S" }, { "family_name": "Catling", "given_name": "David", "clpid": "Catling-D" }, { "family_name": "Lorenz", "given_name": "Ralph", "clpid": "Lorenz-R" }, { "family_name": "Magalh\u00e3es", "given_name": "Julio", "clpid": "Magalh\u00e3es-J" }, { "family_name": "Moersch", "given_name": "Jeffrey", "clpid": "Moersch-J-E" }, { "family_name": "Morgan", "given_name": "Paul", "clpid": "Morgan-P" }, { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" }, { "family_name": "Presley", "given_name": "Marsha", "clpid": "Presley-M" }, { "family_name": "Yen", "given_name": "Albert", "clpid": "Yen-A" }, { "family_name": "Zent", "given_name": "Aaron", "clpid": "Zent-A" }, { "family_name": "Blaney", "given_name": "Diana", "clpid": "Blaney-D" } ], "abstract": "The Mars Microprobe Mission will be the second of the New Millennium Program's technology development missions to planetary bodies. The mission consists of two penetrators that weigh 2.4 kg each and are being carried as a piggyback payload on the Mars Polar Lander cruise ring. The spacecraft arrive at Mars on December 3, 1999. The two identical penetrators will impact the surface at \u223c190 m/s and penetrate up to 0.6 m. They will land within 1 to 10 km of each other and \u223c50 km from the Polar Lander on the south polar layered terrain. The primary objective of the mission is to demonstrate technologies that will enable future science missions and, in particular, network science missions. A secondary goal is to acquire science data. A subsurface evolved water experiment and a thermal conductivity experiment will estimate the water content and thermal properties of the regolith. The atmospheric density, pressure, and temperature will be derived using descent deceleration data. Impact accelerometer data will be used to determine the depth of penetration, the hardness of the regolith, and the presence or absence of 10 cm scale layers.", "doi": "10.1029/1999JE001073", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "1999-11-25", "series_number": "E11", "volume": "104", "issue": "E11", "pages": "27013-27030" }, { "id": "authors:xm595-56b25", "collection": "authors", "collection_id": "xm595-56b25", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140411-153438909", "type": "article", "title": "The Mars Oxidant experiment (MOx) for Mars '96", "author": [ { "family_name": "McKay", "given_name": "Christopher P.", "clpid": "McKay-C-P" }, { "family_name": "Grunthaner", "given_name": "F. J.", "clpid": "Grunthaner-F-J" }, { "family_name": "Lane", "given_name": "A. L.", "clpid": "Lane-A-L" }, { "family_name": "Herring", "given_name": "M.", "clpid": "Herring-M" }, { "family_name": "Bartman", "given_name": "R. K.", "clpid": "Bartman-R-K" }, { "family_name": "Ksendzov", "given_name": "A.", "clpid": "Ksendzov-A" }, { "family_name": "Manning", "given_name": "C. M.", "clpid": "Manning-C-M" }, { "family_name": "Lamb", "given_name": "J. L.", "clpid": "Lamb-J-L" }, { "family_name": "Williams", "given_name": "R. M.", "clpid": "Williams-R-M" }, { "family_name": "Ricco", "given_name": "A. J.", "clpid": "Ricco-A-J" }, { "family_name": "Butler", "given_name": "M. A.", "clpid": "Butler-M-A" }, { "family_name": "Murray", "given_name": "B. C.", "clpid": "Murray-B-C" }, { "family_name": "Quinn", "given_name": "R. C.", "clpid": "Quinn-R-C" }, { "family_name": "Zent", "given_name": "A. P.", "clpid": "Zent-A-P" }, { "family_name": "Klein", "given_name": "H. P.", "clpid": "Klein-H-P" }, { "family_name": "Levin", "given_name": "G. V.", "clpid": "Levin-G-V" } ], "abstract": "The MOx instrument was developed to characterize the reactive nature of the martian soil. The objectives of MOx were: (1) to measure the rate of degradation of organics in the martian environment; (2) to determine if the reactions seen by the Viking biology experiments were caused by a soil oxidant and measure the reactivity of the soil and atmosphere; (3) to monitor the degradation, when exposed to the martian environment, of materials of potential use in future missions; and, finally, (4) to develop technologies and approaches that can be part of future soil analysis instrumentation. The basic approach taken in the MOx instrument was to place a variety of materials composed as thin films in contact with the soil and monitor the physical and chemical changes that result. The optical reflectance of the thin films was the primary sensing mode. Thin films of organic materials, metals, and semiconductors were prepared. Laboratory simulations demonstrated the response of thin films to active oxidants.", "doi": "10.1016/S0032-0633(98)00011-7", "issn": "0032-0633", "publisher": "Elsevier", "publication": "Planetary and Space Science", "publication_date": "1998-06", "series_number": "6-7", "volume": "46", "issue": "6-7", "pages": "769-777" }, { "id": "authors:b5037-p4p59", "collection": "authors", "collection_id": "b5037-p4p59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20130416-131617343", "type": "article", "title": "Water content of the Martian soil: Laboratory simulations of reflectance spectra", "author": [ { "family_name": "Yen", "given_name": "Albert S.", "clpid": "Yen-A-S" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Rossman", "given_name": "George R.", "orcid": "0000-0002-4571-6884", "clpid": "Rossman-G-R" } ], "abstract": "Reflectance spectra from the surface of Mars collected by instruments such as the imaging spectrometer (ISM) onboard the 1988 Soviet Phobos 2 spacecraft exhibit strong 3 \u03bcm absorption features that have long been attributed to hydrated materials on the Martian surface. This interpretation is consistent with a series of chemical weathering models suggesting an abundance of palagonites, clays, and other hydrated mineral phases in the Martian fines. Little work, however, has been done to constrain the actual water content of the Martian surface materials. New laboratory data presented here show that the ISM spectra are consistent with up to 4% water by weight and that the deep hydration features observed in the spacecraft data could be due to less than 0.5% water if the hydrated phases are present in the form of grain coatings. These results are consistent with the somewhat uncertain in situ measurements obtained by the Viking landers which yielded approximately 2 wt % water from samples heated to 500\u00b0C. On the basis of this work, we expect the TEGA instrument on the Mars '98 lander to find less than 4% adsorbed or bound water in the upper few centimeters of the Martian soil.", "doi": "10.1029/98JE00739", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "1998-05-25", "series_number": "E5", "volume": "103", "issue": "E5", "pages": "11125-11133" }, { "id": "authors:m3q6e-3x305", "collection": "authors", "collection_id": "m3q6e-3x305", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-154128676", "type": "article", "title": "A ~ 24000 year period climate signal in 1.7-2.0 million year old Death Valley strata", "author": [ { "family_name": "Hsieh", "given_name": "Jean C. C.", "clpid": "Hsieh-J-C-C" }, { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" } ], "abstract": "Continental records of Plio-Pleistocene climatic fluctuations are often confined to fragmentary, localized basins, and not easily dated. One exception is the Confidence Hills of Southern Death Valley. In this study, we present a detailed description of a Plio-Pleistocene section of interfingering alluvial fan and saltpan sediments from the Confidence Hills, southern Death Valley. This well exposed section accumulated with an average deposition rate of \u223c 25 cm/1000 yr with no bioturbation, permitting more precise paleomagnetic dating than in oceanic records [1]. We interpret the sequence of facies changes in the Olduvai Normal Polarity Zone of the Confidence Hills to represent alternations between wetter and drier regional climatic regimes. The frequency of this variation (\u223c 24 000 yr) appears to correspond to the Milankovitch precessional cycle (23 000 yr). We believe this section records a Milankovitch-driven climatic variation in the Death Valley basin annual precipitation about 1.7\u20132.0 Ma. This is the first report of the precessional cycle in continental sediments of this age in the United States.", "doi": "10.1016/0012-821X(96)00075-1", "issn": "0012-821X", "publisher": "Elsevier", "publication": "Earth and Planetary Science Letters", "publication_date": "1996-06", "series_number": "1-4", "volume": "141", "issue": "1-4", "pages": "11-19" }, { "id": "authors:dc0dj-24h94", "collection": "authors", "collection_id": "dc0dj-24h94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140411-130807957", "type": "article", "title": "Plio-Pleistocene deposits adjacent to the Manix fault: implications for the history of the Mojave River and Transverse Ranges uplift", "author": [ { "family_name": "Nagy", "given_name": "Elizabeth A.", "clpid": "Nagy-E-A" }, { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" } ], "abstract": "A nearly continuous sedimentary record encompassing more than 2 million years of Plio-Pleistocene history is exposed by downcutting of the Mojave River adjacent to the Manix fault in the central Mojave Desert. This stratigraphic record, combined with local structural information, suggests that north-south crustal shortening took place adjacent to the Manix fault between about 1 and 0.5 Ma. Strike-slip deformation predominated along the Manix fault in the study area since 0.5-0.3 Ma and continues today.\n\nNo evidence is found within the deposits for sustained eastward flow of the Mojave River system prior to 0.5 Ma, even though the Transverse Ranges uplift at San Bernardino Arch, the headwater region of the modern river system, has been estimated between 1.0 and 0.7 Ma. Understanding recent deformation in this region is especially warranted by the proximity and geometry between the Manix fault and a conspicuous gap in seismicity following the 1992 Landers earthquake sequence.", "doi": "10.1016/0037-0738(95)00076-3", "issn": "0037-0738", "publisher": "Elsevier", "publication": "Sedimentary Geology", "publication_date": "1996-05", "series_number": "1-2", "volume": "103", "issue": "1-2", "pages": "9-21" }, { "id": "authors:6x2fj-bjw74", "collection": "authors", "collection_id": "6x2fj-bjw74", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140410-094854047", "type": "article", "title": "Nonlinear Spectral Mixing in Desert Vegetation", "author": [ { "family_name": "Ray", "given_name": "Terrill W.", "clpid": "Ray-T-W" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "Linear mixing models are widely used in terrestrial remote sensing, with the errors in these models being often attributed to \"nonlinear\" mixing. Nonlinear mixing refers to the interaction of light with multiple target materials. Reflectance data from creosote bush in the Manix Basin of the Mojave Desert is used to show the existence and importance of nonlinear mixing in and region vegetation. It shows that the difference in the reflectance spectrum of plants against a soil background and the spectrum of the plant against a dark background is well represented by light that has interacted with both the soil and the plant.", "doi": "10.1016/0034-4257(95)00171-9", "issn": "0034-4257", "publisher": "Elsevier", "publication": "Remote Sensing of Environment", "publication_date": "1996-01", "series_number": "1", "volume": "55", "issue": "1", "pages": "59-64" }, { "id": "authors:f44ha-vxv06", "collection": "authors", "collection_id": "f44ha-vxv06", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140630-094825024", "type": "article", "title": "Thermal inertias in the upper millimeters of the Martian surface derived using Phobos' shadow", "author": [ { "family_name": "Betts", "given_name": "Bruce H.", "orcid": "0000-0002-4423-5800", "clpid": "Betts-B-H" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Sv\u00edtek", "given_name": "Tom\u00e1\u0161", "clpid": "Sv\u00edtek-T" } ], "abstract": "The first thermal images of Phobos' shadow on the surface of Mars, in addition to simultaneous visible images, were obtained by the Phobos '88 Termoskan instrument. The best observed shadow occurrence was on the flanks of Arsia Mons. For this occurrence, we combined the observed decrease in visible illumination of the surface with the observed decrease in brightness temperature to calculate thermal inertias of the Martian surface. The most realistic of our three models of eclipse cooling improves upon our preliminary model by including nonisothermal initial conditions and downward atmospheric flux. Most of our derived inertias fall within the range 38 to 59 J m^(\u22122) s^(\u22121)/2 K^(\u22121) (0.9 to 1.4 10\u22123 cal cm^(\u22122) s^(\u22121)/2 K^(\u22121)), corresponding to dust-sized particles (for a homogeneous surface), consistent with previous theories of Tharsis as a current area of dust deposition. Viking infrared thermal mapper (IRTM) inertias are diurnally derived and are sensitive to centimeter depths, whereas the shadow-derived inertias sample the upper tenths of a millimeter of the surface. The shadow-derived inertias are lower than those derived from Viking IRTM measurements (84 to 147), however, uncertainties in both sets of derived inertias make conclusions about layering tenuous. Thus, near-surface millimeter versus centimeter layering may exist in this region, but if it does, it is likely not very significant. Both eclipse and diurnal inertias appear to increase near the eastern end of the shadow occurrence. We also analyzed a shadow occurrence near the crater Herschel that showed no observed cooling. This analysis was limited by cool morning temperatures and instrument sensitivity, but yielded a lower bound of 80 on eclipse inertias in that region. Based upon our results, we strongly recommend future spacecraft thermal observations of Phobos' shadow, and suggest that they will be most useful if they improve upon Termoskan's geographic and temporal coverage and its accuracy.", "doi": "10.1029/95JE00226", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "1995-03-25", "series_number": "E3", "volume": "100", "issue": "E3", "pages": "5285-5296" }, { "id": "authors:xqhtw-gax68", "collection": "authors", "collection_id": "xqhtw-gax68", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140415-090236800", "type": "article", "title": "Thermal studies of Martian channels and valleys using Termoskan data", "author": [ { "family_name": "Betts", "given_name": "Bruce H.", "orcid": "0000-0002-4423-5800", "clpid": "Betts-B-H" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "The Termoskan instrument on board the Phobos '88 spacecraft acquired the highest spatial resolution thermal infrared emission data ever obtained for Mars. Included in the thermal images are 2 km/pixel, midday observations of several major channel and valley systems including significant portions of Shalbatana, Ravi, Al-Qahira, and Ma'adim Valles, the channel connecting Valles Marineris with Hydraotes Chaos, and channel material in Eos Chasma. Termoskan also observed small portions of the southern beginnings of Simud, Tiu, and Ares Valles and some channel material in Gangis Chasma. Simultaneous broadband visible reflectance data were obtained for all but Ma'adim Vallis. We find that most of the channels and valleys have higher thermal inertias than their surroundings, consistent with previous thermal studies. We show for the first time that the thermal inertia boundaries closely match flat channel floor boundaries. Also, buttes within channels have inertias similar to the plains surrounding the channels, suggesting the buttes are remnants of a contiguous plains surface. Lower bounds on typical channel thermal inertias range from 8.4 to 12.5 (10^(\u22123) cal cm^(\u22122) s^(\u22121/2) K^(\u22121)) (352 to 523 in SI units of J m^(\u22122) s^(\u22121/2) K^(\u22121)). Lower bounds on inertia differences with the surrounding heavily cratered plains range from 1.1 to 3.5 (46 to 147 SI). Atmospheric and geometric effects are not sufficient to cause the observed channel inertia enhancements. We favor nonaeolian explanations of the overall channel inertia enhancements based primarily upon the channel floors' thermal homogeneity and the strong correlation of thermal boundaries with floor boundaries. However, localized, dark regions within some channels are likely aeolian in nature as reported previously. Most channels with increased inertias have fretted morphologies such as flat floors with steep walls. Eastern Ravi and southern Ares Valles, the only major channel sections observed that have obvious catastrophic flood bedforms, do not have enhanced inertias. Therefore, we favor fretting processes over catastrophic flooding for explaining the inertia enhancements. We postulate that the inertia enhancements were caused either by the original fretting process or by a process involving the bonding of fines due to an increased availability of water, either initially or secondarily.", "doi": "10.1029/93JE03173", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "1994-01-25", "series_number": "E1", "volume": "99", "issue": "E1", "pages": "1983-1996" }, { "id": "authors:emmn9-bd143", "collection": "authors", "collection_id": "emmn9-bd143", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-152254992", "type": "article", "title": "Thermally distinct ejecta blankets from Martian craters", "author": [ { "family_name": "Betts", "given_name": "Bruce H.", "orcid": "0000-0002-4423-5800", "clpid": "Betts-B-H" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "Utilizing the Termoskan data set of the Phobos '88 mission we have recognized a new feature on Mars: ejecta blanket distinct in the thermal infrared (EDITH). Virtually all of the more than 100 features discovered in the Termoskan data are located on the plains near Valles Marineris. EDITHs have a startlingly clear dependence upon terrains of Hesperian age, implying a spatial or temporal dependence on Hesperian terrains. Almost no thermally distinct ejecta blankets are associated with any of the thousands of craters within the data set that occur on the older Noachian units. EDITHs also do not appear on the portions of the younger Tharsis Amazonian units seen in the data. The Hesperian terrain dependence cannot be explained by either atmospheric or impactor variations; Noachian and Hesperian terrains must have experienced identical atmospheric and impactor conditions during Hesperian times. Thermally distinct ejecta blankets therefore reflect target material differences and/or secondary modification processes. Not all lobate ejecta blankets are thermally distinct, but all EDITHs correlated with visibly discernible ejecta blankets are associated with lobate ejecta blankets. The boundaries of the thermally distinct areas usually follow closely the termini of the fluidized lobate ejecta blankets, even when the ejecta blankets show a high degree of sinuosity. Thus, the thermally distinct nature of EDITHs must be due to the primary ejecta formation process. The coupling of these thermal anomalies to morphology is unlike most sharp Martian inertia variations which are decoupled from observed surface morphology. Some thermally distinct ejecta blankets occur near otherwise similar craters that do not have thermally distinct ejecta blankets. Thus, wind patterns or locally available aeolian material cannot provide a single overall explanation for the observed variations. We compiled a data base of 110 EDITH and non-EDITH craters ranging in diameter from 4.2 km to 90.6 km. There are almost no correlations within the data base other than occurrence on Hesperian terrains. We postulate that most of the observed EDITHs are due to excavation of thermally distinctive Noachian age material from beneath a relatively thin layer of younger, more consolidated Hesperian volcanic material. The plausibility of this theory is supported by much geological evidence for relatively thin near-surface Hesperian deposits overlying massive Noachian megabreccias on the EDITH-rich plains units. We suggest that absence of thermally distinct ejecta blankets on Noachian and Amazonian terrains is due to absences of distinctive near-surface layering. Thermally distinct ejecta blankets are excellent locations for future landers and remote sensing because of relatively dust free surface exposures of material excavated from depth.", "doi": "10.1029/93JE00107", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research E", "publication_date": "1993-06-25", "series_number": "E6", "volume": "98", "issue": "E6", "pages": "11043-11059" }, { "id": "authors:f00ew-sp056", "collection": "authors", "collection_id": "f00ew-sp056", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20121205-153626186", "type": "article", "title": "Stability of polar frosts in spherical bowl-shaped craters on the Moon, Mercury, and Mars", "author": [ { "family_name": "Ingersoll", "given_name": "Andrew P.", "orcid": "0000-0002-2035-9198", "clpid": "Ingersoll-A-P" }, { "family_name": "Svitek", "given_name": "Tomas", "clpid": "Svitek-T" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "Following Svitek (Martian Water Frost: Control of Global Distribution by Small-Scale Processes, Ph.D Thesis, California Institute of Technology, 1992), analytic solutions are presented for the effective albedo, the effective emissivity, and the radiative equilibrium temperature in the shadowed portions of a spherical bowl-shaped crater. The model assumes that the surface is a Lambert scatterer with visual albedo and infrared emissivity each independent of wavelength across their respective spectral ranges. Absorption, emission, and multiple scattering from the walls of the crater are treated rigorously to all orders. For airless bodies whose surfaces are in radiative equilibrium, all shadowed portions of any individual crater have the same temperature, whose value depends on four quantities: the insolation (product of the solar constant and the sine of the solar elevation angle), the depth/diameter ratio of the crater, the visual albedo, and the infrared emissivity. As long as the crater is deep enough to have shadows, the lowest temperatures are for the shallowest crater\u2014those with the smallest depth/diameter ratio. The model is applied first to the Moon and Mercury using a depth/diameter ratio of 0.2, which is typical of the lunar highlands according to Pike (Geophys. Res. Lett. 1, 291\u2013294 (1974); in Impact and Explosion Cratering (Roddy et al., Eds.), pp. 489\u2013509, Pergamon, New York, 1977). For Mercury and the Moon, temperatures in shadows in polar craters are below 102 K, so the sublimation rate of water ice calculated according to the model of Watson et al. (J. Geophys. Res. 66, 3033-3015 (1961)) is less than 1 cm per byr. The latitudinal extent of the cold zone on the Moon is greater than that on Mercury, although temperatures at the poles of the two planets are similar. The other application is to polar frosts on Mars. Illuminated water frosts in radiative equilibrium grow rougher, because the average temperature of a depression is greater than that of flat ground. Subliming CO_2 frosts, which are always at the same temperature, grow rougher at low solar elevation angles because the heat flux absorbed by a depression is greater than that for a flat surface. At high insolation rates (high Sun near perihelion) the average heat flux to a depression is less than for a flat surface. The latter evaporates faster, which makes the average surface smoother and leads to a high average albedo. This behavior helps explain the fact that the south CO_2 cap, which receives its greatest insolation near perihelion, has a higher effective albedo and therefore can survive the summer, whereas the north CO_2 cap has a lower effective albedo and disappears each year around summer solstice.", "doi": "10.1016/0019-1035(92)90016-Z", "issn": "0019-1035", "publisher": "Elsevier", "publication": "Icarus", "publication_date": "1992-11", "series_number": "1", "volume": "100", "issue": "1", "pages": "40-47" }, { "id": "authors:1ync8-82n26", "collection": "authors", "collection_id": "1ync8-82n26", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140522-095250927", "type": "article", "title": "Can space exploration survive the end of the Cold War?", "author": [ { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" } ], "abstract": "The first, heroic age of space exploration was driven by national rivalry between the USA and USSR. There have indeed been recent achievements, but as the Cold War ends the superpowers are turning their attention to domestic issues and the prospect looms of a prolonged hiatus in space exploration. The only way forward is through international cooperation, but this will never happen without a serious investment of political will. A well-planned, long-term strategy for the exploration of Mars could provide the necessary focus.", "doi": "10.1016/0265-9646(91)90043-H", "issn": "0265-9646", "publisher": "Elsevier", "publication": "Space Policy", "publication_date": "1991-02", "series_number": "1", "volume": "7", "issue": "1", "pages": "23-34" }, { "id": "authors:10sha-1vr17", "collection": "authors", "collection_id": "10sha-1vr17", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140410-093610366", "type": "article", "title": "Results of TV imaging of Phobos (experiment VSK-FREGAT)", "author": [ { "family_name": "Avanesov", "given_name": "G.", "clpid": "Avanesov-G-A" }, { "family_name": "Murray", "given_name": "B.", "clpid": "Murray-B-C" }, { "family_name": "Herkenhoff", "given_name": "K.", "orcid": "0000-0002-3153-6663", "clpid": "Herkenhoff-K-E" } ], "abstract": "From February to March 1989 the Phobos 2 spacecraft took 37 TV images of Phobos at a distance of 190\u20131100 km. These images complement Mariner-9 and Viking data by providing higherresolution coverage of a large region West of the crater Stickney (40\u2013160\u00b0W) and by providing disk-resolved measurements of surface brightness at a greater range of wavelengths and additional phase angles. These images have supported updated mapping and characterization of large craters and grooves, and have provided additional observations of craters' and grooves' bright rims. Variations in surface visible/nearinfrared color ratio of almost a factor of 2 have been recognized ; these variations appear to be associated with the ejecta of specific large impact craters. Updated determinations of satellite mass and volume allow calculation of a more accurate value of bulk density, 1.90 \u00b1 0.1 g cm^(\u22123). This is significantly lower than the density of meteoritic analogs to Phobos' surface, suggesting a porous interior perhaps containing interstitial ice.", "doi": "10.1016/0032-0633(91)90150-9", "issn": "0032-0633", "publisher": "Elsevier", "publication": "Planetary and Space Science", "publication_date": "1991-01", "series_number": "1-2", "volume": "39", "issue": "1-2", "pages": "281-295" }, { "id": "authors:ge93n-nft13", "collection": "authors", "collection_id": "ge93n-nft13", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140410-092259617", "type": "article", "title": "Preliminary assessment of Termoskan observations of Mars", "author": [ { "family_name": "Murray", "given_name": "B.", "clpid": "Murray-B-C" }, { "family_name": "Naraeva", "given_name": "M. K.", "clpid": "Naraeva-M-K" }, { "family_name": "Selivanov", "given_name": "A. S.", "clpid": "Selivanov-A-S" }, { "family_name": "Betts", "given_name": "B. H.", "orcid": "0000-0002-4423-5800", "clpid": "Betts-B-H" }, { "family_name": "Svitek", "given_name": "T.", "clpid": "Svitek-T" }, { "family_name": "Kharlamov", "given_name": "V. D.", "clpid": "Kharlamov-V-D" }, { "family_name": "Romanov", "given_name": "A. V.", "clpid": "Romanov-A-V" }, { "family_name": "Santee", "given_name": "M. L.", "clpid": "Santee-M-L" }, { "family_name": "Gektin", "given_name": "Y. M.", "clpid": "Gektin-Y-M" }, { "family_name": "Fomin", "given_name": "D. A.", "clpid": "Fomin-D-A" }, { "family_name": "Paige", "given_name": "D. A.", "clpid": "Paige-D-A" }, { "family_name": "Panfilov", "given_name": "A. S.", "clpid": "Panfilov-A-S" }, { "family_name": "Crisp", "given_name": "D.", "orcid": "0000-0002-4573-9998", "clpid": "Crisp-D" }, { "family_name": "Head", "given_name": "J. W.", "orcid": "0000-0003-2013-560X", "clpid": "Head-J-W" }, { "family_name": "Murchie", "given_name": "S. L.", "orcid": "0000-0002-1616-8751", "clpid": "Murchie-S-L" }, { "family_name": "Martin", "given_name": "T. Z.", "clpid": "Martin-T-Z" } ], "abstract": "In February and March, 1989, the Termoskan instrument onboard the Phobos '88 spacecraft acquired a limited set of very high resolution observations of the 8\u201312 \u03bcm thermal emission from Mars' equatorial regions. Simultaneous and coincident observations were acquired in the 0.5 to 1.0 \u03bcm region also. We have evaluated quantitatively about 25% of those data and find close agreement with the lower-resolution Viking Orbiter Infrared Thermal Mapper (IRTM) observations, demonstrating the accuracy of the Termoskan system. Termoskan's thermal emission panoramas display limb brightening at the morning limb, which we interpret as arising from the presence of a diurnal ice crystal haze there. Detached hazes at high altitude also are evident in the visible panorama of the evening limb. The Phobos '88 orbit enabled Termoskan to record the visible shadow from the Martian moonlet Phobos and to measure the surface thermal response to that shadow's passage. Analysis of one such data set shows that the uppermost fraction of a millimeter is two to four times more insulating than the uppermost centimeters sensed by the IRTM experiment. The Termoskan data are of direct importance to the planning and execution of the PMIRR and TES experiments of the U.S. Mars Observer mission to be launched in 1992. An improved version of Termoskan is planned for the Mars '94 mission of the U.S.S.R. Those data will be of still higher surface resolution and, thus, complement well the expected PMIRR and TES global data sets.", "doi": "10.1016/0032-0633(91)90147-3", "issn": "0032-0633", "publisher": "Elsevier", "publication": "Planetary and Space Science", "publication_date": "1991-01", "series_number": "1-2", "volume": "39", "issue": "1-2", "pages": "237-265" }, { "id": "authors:2cbj1-rrf04", "collection": "authors", "collection_id": "2cbj1-rrf04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140410-085823997", "type": "article", "title": "Phobos: Spectrophotometry between 0.3 and 0.6 \u03bcm and IR-radiometry", "author": [ { "family_name": "Ksanfomality", "given_name": "L.", "clpid": "Ksanfomality-L" }, { "family_name": "Murchie", "given_name": "S.", "orcid": "0000-0002-1616-8751", "clpid": "Murchie-S-L" }, { "family_name": "Britt", "given_name": "D.", "clpid": "Britt-D" }, { "family_name": "Duxbury", "given_name": "T.", "clpid": "Duxbury-T" }, { "family_name": "Fisher", "given_name": "P.", "clpid": "Fisher-P" }, { "family_name": "Goroshkova", "given_name": "N.", "clpid": "Goroshkova-N" }, { "family_name": "Head", "given_name": "J.", "clpid": "Head-J" }, { "family_name": "Kuhrt", "given_name": "E.", "clpid": "Kuhrt-E" }, { "family_name": "Moroz", "given_name": "V.", "clpid": "Moroz-V" }, { "family_name": "Murray", "given_name": "B.", "clpid": "Murray-B-C" }, { "family_name": "Nikitin", "given_name": "G.", "clpid": "Nikitin-G" }, { "family_name": "Petrova", "given_name": "E.", "clpid": "Petrova-E" }, { "family_name": "Pieters", "given_name": "C", "clpid": "Pieters-C" }, { "family_name": "Soufflot", "given_name": "A.", "clpid": "Soufflot-A" }, { "family_name": "Zharkov", "given_name": "A.", "clpid": "Zharkov-A" }, { "family_name": "Zhukov", "given_name": "B.", "clpid": "Zhukov-B" } ], "abstract": "A 0.3\u20130.6 (\u03bcm UV-visible spectrophotometer and a 5\u201350 \u03bcm radiometer in the KRFM experiment on Phobos 2 measured two groundtracks in the equatorial region of Phobos. Preliminary results indicate that three surface units can be recognized on the basis of differing UV-visible spectral reflectance properties. One of the units is most comparable spectrally to optically darkened mafic material, and a second is comparable either to anhydrous carbonaceous chondrite or to blackened mafic material. Spectral properties of the third unit do not resemble those of known meteorite types. Brightness temperatures measured by the radiometer are consistent with a typlcal surface thermal inertia of 1-3 x 10^(-3) cal/(cm^2) deg S^(1/2), as suggested by previous investigations, implying a lunar-like regolith texture. At least one area of possibly higher thermal inertia has been tentatively identified, where a large degraded crater is crossed by several grooves. These results indicate significant lateral heterogeneity in the optical and textural properties of Phobos's surface.", "doi": "10.1016/0032-0633(91)90152-Z", "issn": "0032-0633", "publisher": "Elsevier", "publication": "Planetary and Space Science", "publication_date": "1991-01", "series_number": "1-2", "volume": "39", "issue": "1-2", "pages": "311-326" }, { "id": "authors:ej45z-f2868", "collection": "authors", "collection_id": "ej45z-f2868", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-133726762", "type": "article", "title": "High-Resolution Topography and Albedo of the South Polar Layered Deposits on Mars", "author": [ { "family_name": "Herkenhoff", "given_name": "Ken E.", "orcid": "0000-0002-3153-6663", "clpid": "Herkenhoff-K-E" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "Using a new photoclinometric technique with high-resolution Mariner 9 images, maximum slopes of 10\u00b0\u201320\u00b0 are found to occur on an exposure of layered deposits within the south polar residual cap of Mars. Stereophotogrammetry is used to constrain the photoclinometric solutions, which resolve layer thicknesses of 100\u2013300 m. Albedo variations are correlated with slope, indicating that frost is present on level areas. There is evidence for temporal changes in frost distribution in the 7 days (4\u00b0 of L_S) between the two images used in this study. The magnitude of the slopes derived here and consideration of the stability of water ice at the surface of the layered deposits strongly suggest the presence of a competent weathering rind. The weathered surface may be composed of dark filamentary sublimation residue particles that protect the underlying ice from solar heating. This hypothesis is consistent with previous studies of the regional color and albedo of the layered deposits, which indicate that the deposits are slightly darker and less red than the bright dust that mantles much of the south polar region. Furthermore, the proposed weathering mechanism provides a plausible source of dark, saltating material for the Martian polar dune fields.", "doi": "10.1029/JB095iB09p14511", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research B", "publication_date": "1990-08-30", "series_number": "B9", "volume": "95", "issue": "B9", "pages": "14511-14529" }, { "id": "authors:97569-gwv84", "collection": "authors", "collection_id": "97569-gwv84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140414-082134007", "type": "article", "title": "Destination Mars - a manifesto", "author": [ { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" } ], "abstract": "In proposing a manned mission to Mars, President Bush has allowed Americans to dream again of greatness as a space-faring nation. But dream is more likely to become reality with the help of the Soviet Union.", "doi": "10.1038/345199a0", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "1990-05-17", "series_number": "6272", "volume": "345", "issue": "6272", "pages": "199-200" }, { "id": "authors:6t9q7-rfa45", "collection": "authors", "collection_id": "6t9q7-rfa45", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-143301324", "type": "article", "title": "Ice Sublimation and Rheology: Implications for the Martian\n Polar Layered Deposits", "author": [ { "family_name": "Hofstadter", "given_name": "Mark D.", "clpid": "Hofstadter-M-D" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "It has been suggested that the Martian polar layered deposits are composed largely of water ice. If true, then sublimation and deformation creep of the ice are important processes. Simple models indicate that sublimation will occur at a rate inconsistent with current estimates of the deposit's age and Viking observations of the atmospheric water abundance, suggesting that when considering the formation, evolution, and structure of the deposits, one must include a mechanism by which sublimation is inhibited. A surface layer of dust seems the most likely possibility. Additionally, over the age of the deposits, flows of at least 1 km are expected. At Viking resolution (\u2a7e150 m) no obvious flow features are observed. Assuming that Martian features would be similar to those that occur on the Earth, this limits the maximum flow rates possible and suggest the deposits need to be more than 90% ice or less than about 40% ice by volume. The Mars Observer spacecraft will be able to constrain the ice abundance further by both searching for flow features and clarifying the nature of the deposit's surface and near surface.", "doi": "10.1016/0019-1035(90)90043-9", "issn": "0019-1035", "publisher": "Elsevier", "publication": "Icarus", "publication_date": "1990-04", "series_number": "2", "volume": "84", "issue": "2", "pages": "352-361" }, { "id": "authors:9mhny-pdy95", "collection": "authors", "collection_id": "9mhny-pdy95", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140416-103830800", "type": "article", "title": "Television pictures of Phobos: first results", "author": [ { "family_name": "Avanesov", "given_name": "G. A.", "clpid": "Avanesov-G-A" }, { "family_name": "Bonev", "given_name": "B. I.", "clpid": "Bonez-B-I" }, { "family_name": "Kempe", "given_name": "F.", "clpid": "Kempe-F" }, { "family_name": "Bazilevskii", "given_name": "A. T.", "clpid": "Bazilevskii-A-T" }, { "family_name": "Boicheva", "given_name": "V.", "clpid": "Boicheva-V" }, { "family_name": "Wiede", "given_name": "G. -G.", "clpid": "Wiede-G-G" }, { "family_name": "Gromatikov", "given_name": "P.", "clpid": "Gromatikov-P" }, { "family_name": "Duxbury", "given_name": "T.", "clpid": "Duxbury-T" }, { "family_name": "Danz", "given_name": "M.", "clpid": "Danz-M" }, { "family_name": "Dimitrov", "given_name": "D.", "clpid": "Dimitrov-D" }, { "family_name": "Zhukov", "given_name": "B. S.", "clpid": "Zhukov-B-S" }, { "family_name": "Ziman", "given_name": "Ya. L.", "clpid": "Ziman-Y-L" }, { "family_name": "Kolev", "given_name": "V.", "clpid": "Kolev-V" }, { "family_name": "Kostenko", "given_name": "V. I.", "clpid": "Kostenko-V-I" }, { "family_name": "Kottsov", "given_name": "V. A.", "clpid": "Kottsov-V-A" }, { "family_name": "Krasavtsev", "given_name": "V. M.", "clpid": "Krasavtsev-V-M" }, { "family_name": "Krasikov", "given_name": "V. A.", "clpid": "Krasikov-V-A" }, { "family_name": "Krumov", "given_name": "A.", "clpid": "Krumov-A" }, { "family_name": "Kuz'min", "given_name": "A. A.", "clpid": "Kuz'min-A-A" }, { "family_name": "Losev", "given_name": "K. D.", "clpid": "Losev-K-D" }, { "family_name": "Lumme", "given_name": "K.", "clpid": "Lumme-K" }, { "family_name": "Mohlmmann", "given_name": "D.", "clpid": "Mohlmmann-D" }, { "family_name": "Murchie", "given_name": "S.", "orcid": "0000-0002-1616-8751", "clpid": "Murchie-S-L" }, { "family_name": "Mishev", "given_name": "D. N.", "clpid": "Mishev-D-N" }, { "family_name": "Muinonen", "given_name": "K.", "clpid": "Muinonen-K" }, { "family_name": "Murav'ev", "given_name": "V. M.", "clpid": "Murav'ev-V-M" }, { "family_name": "Murray", "given_name": "B.", "clpid": "Murray-B-C" }, { "family_name": "Neumann", "given_name": "W.", "clpid": "Neumann-W" }, { "family_name": "Paul", "given_name": "L.", "clpid": "Paul-L" }, { "family_name": "Possel", "given_name": "W.", "clpid": "Possel-W" }, { "family_name": "Petkov", "given_name": "D.", "clpid": "Petkov-D" }, { "family_name": "Petukhova", "given_name": "P.", "clpid": "Petukhova-P" }, { "family_name": "Rebel", "given_name": "B.", "clpid": "Rebel-B" }, { "family_name": "Simeonov", "given_name": "S.", "clpid": "Simeonov-S" }, { "family_name": "Smith", "given_name": "B.", "clpid": "Smith-B" }, { "family_name": "Totev", "given_name": "A.", "clpid": "Totev-A" }, { "family_name": "Uzunov", "given_name": "Yu.", "clpid": "Uzunov-Y" }, { "family_name": "Fedotov", "given_name": "V. P.", "clpid": "Fedotov-V-P" }, { "family_name": "Halman", "given_name": "D.", "clpid": "Halman-D" }, { "family_name": "Head", "given_name": "J.", "clpid": "Head-J" }, { "family_name": "Heifets", "given_name": "V. N.", "clpid": "Heifets-V-N" }, { "family_name": "Zapfe", "given_name": "H.", "clpid": "Zapfe-H" }, { "family_name": "Chikov", "given_name": "K. N.", "clpid": "Chikov-K-N" }, { "family_name": "Shkuratov", "given_name": "Yu. G.", "clpid": "Shkuratov-Y-G" } ], "abstract": "In February-March 1989, 37 television images of the Martian satellite Phobos were obtained by the Phobos 2 spacecraft from distances of 200-1100 km. These images provide an important supplement to the TV data from the American Mariner 9 and Viking spacecraft in coverage of t4e surface of Phobos and in resolution in certain regions, in spectral range, and in range of phase angles. They make it possible to refine the figure and topographic and geological maps of the surface of Phobos, its spectral and angular reflective characteristics,\nthe surface composition and texture, and characteristics of the orbital and librational motion.", "issn": "0360-0327", "publisher": "American Institute of Physics", "publication": "Soviet Astronomy Letters", "publication_date": "1990-03", "series_number": "2", "volume": "16", "issue": "2", "pages": "160-164" }, { "id": "authors:gbmdq-61x92", "collection": "authors", "collection_id": "gbmdq-61x92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140415-114315955", "type": "article", "title": "Winter Frost at Viking Lander 2 Site", "author": [ { "family_name": "Svitek", "given_name": "Thomas", "clpid": "Svitek-T" }, { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" } ], "abstract": "A key question in the study of Mars is water exchange between atmosphere and surface on daily, seasonal, and astronomical timescales. We believe that small-scale processes are a key for enhanced understanding of the global water behavior of Mars. The principal data for this study of small scale properties of the Martian surface were collected by the second Viking lander (VL 2) and by both Viking orbiters. The annual deposition and retreat of the frost layer were observed in situ by VL 2. The frost is inferred to be H_2O frost but with some properties suggesting a much thicker layer than would be expected from the simple mass balance calculation. Our original contribution is in considering the effect of cold trapping (frost redeposition) which has been previously neglected and which enables us to reconcile all the observations with environmental conditions. In addition, we believe that this study points to a more general phenomenon of cold trapping in the Martian environment. Our study of the VL 2 observations suggests that H_2O frost occurs in two forms: (1) thin, almost continuous, early frost and (2) much thicker, patchy, later frost. Both frost forms contain essentially the same total water content, but they cover different fractions of the surface. The transition between the two frost forms occurs by recondensation at local cold traps when solar insolation sublimates the first frost but the atmosphere is still too cold to transport the resultant water vapor away. These cold traps are created by shadowing from the small-scale surface roughness, rocks, troughs, etc. This hypothesis hinges on the disparity between local and long-range transport of water vapor by the atmosphere. The local transport is driven by abundant insolation energy available at the time of transition. This results in a large fraction of surface frost being redistributed rapidly into locally thermodynamically preferable locations, cold traps. Long-range transport is constrained by the atmospheric carrying capacity. At the time of transition, the atmosphere is still cold, not far from its winter minimum, and is almost saturated by residual water vapor (5\u20138 precipitable micrometers). Therefore it cannot carry much additional water vapor to lower latitudes. This disparity delays the global transport of water vapor by the atmosphere.", "doi": "10.1029/JB095iB02p01495", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research B", "publication_date": "1990-02-10", "series_number": "B2", "volume": "95", "issue": "B2", "pages": "1495-1510" }, { "id": "authors:xdmfy-bad09", "collection": "authors", "collection_id": "xdmfy-bad09", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-143732489", "type": "article", "title": "Color and Albedo of the South Polar Layered Deposits on Mars", "author": [ { "family_name": "Herkenhoff", "given_name": "Ken E.", "orcid": "0000-0002-3153-6663", "clpid": "Herkenhoff-K-E" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "Five color/albedo units, including polar frost, have been recognized and mapped in the southern layered deposits on Mars. Atmospheric dust scattering was measured in shadows and modeled in order to remove the component of brightness in Mars images due to the atmosphere and quantify the albedo and color of the surface. The layered deposits appear to be mantled by red dust, except where eolian stripping has exposed the underlying bedrock. Frost and bare ground are mixed below the resolution of the images in many areas adjacent to the polar cap, some of which appear to be younger than the surrounding layered terrain. Dark material has been deposited in topographic depressions in much of the south polar region, including the layered deposits. The available observational data suggest that the layered deposits are composed of bright dust, ice, and a small amount of dark material. If the dark material is sand, a periodic change in polar winds seems required in order to transport the sand poleward into the layered terrain. In any case, the observations are not consistent with the layered\ndeposits being composed only of bright dust and ice. The Mars observer camera and infrared instruments should be particularly useful in this investigation", "doi": "10.1029/JB095iB02p01343", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research B", "publication_date": "1990-02-10", "series_number": "B2", "volume": "95", "issue": "B2", "pages": "1343-1358" }, { "id": "authors:w0bnx-zfh31", "collection": "authors", "collection_id": "w0bnx-zfh31", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140414-160713373", "type": "article", "title": "Mariner 9 Observations of the South Polar Cap of Mars' Evidence for Residual CO\u2082 Frost", "author": [ { "family_name": "Paige", "given_name": "D. A.", "clpid": "Paige-D-A" }, { "family_name": "Herkenhoff", "given_name": "K. E.", "orcid": "0000-0002-3153-6663", "clpid": "Herkenhoff-K-E" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "The first spacecraft observations of the south residual polar cap of Mars were obtained by the Mariner 9 orbiter during the Martian southern summer season, 1971\u20131972. Analyses of Viking orbiter observations obtained 3 Mars years later have shown that residual carbon dioxide frost was present at the south polar cap in 1977. In this study, Mariner 9 infrared interferometer spectrometer spectra and television camera images are used in conjunction with multispectral thermal emission models to constrain the temperatures of dark bare ground and bright frost regions within the south residual cap. The results provide strong evidence that carbon dioxide frost was present throughout the summer season despite the fact that the residual frost deposits observed by Mariner 9 were less extensive than those observed by Viking.", "doi": "10.1029/JB095iB02p01319", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research B", "publication_date": "1990-02-10", "series_number": "B2", "volume": "95", "issue": "B2", "pages": "1319-1335" }, { "id": "authors:me5wd-jmm39", "collection": "authors", "collection_id": "me5wd-jmm39", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-125756957", "type": "article", "title": "Television observations of Phobos", "author": [ { "family_name": "Avanesov", "given_name": "G. A.", "clpid": "Avanesov-G-A" }, { "family_name": "Murray", "given_name": "B.", "clpid": "Murray-B-C" } ], "abstract": "In February and March 1989 the Phobos 2 spacecraft took 37 television images of the moon Phobos from a distance of 190-1,100 km. These images complement the data from the Mariner 9 and Viking missions by providing higher-resolution coverage of a large region west of the crater Stickney (70-160\u00b0 W) and by providing disk-resolved measurements of surface brightness at a greater range of phase angles and wavelengths. The data are being used to update the three-dimensional model of Phobos, to provide improved determinations of its density and orbital dynamics and to study its surface colour, composition and texture. Here we present preliminary findings, which include different integrated photometric behaviour in visible and near-infrared bands, observation of a region immediately west of Stickney which is relatively free of large grooves, the prevalence of bright rims on grooves and younger craters and low bulk density.", "doi": "10.1038/341585a0", "issn": "0028-0836", "publisher": "Nature Publishing Group", "publication": "Nature", "publication_date": "1989-10-19", "series_number": "6243", "volume": "341", "issue": "6243", "pages": "585-587" }, { "id": "authors:a2hk5-j0448", "collection": "authors", "collection_id": "a2hk5-j0448", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20131211-151001621", "type": "article", "title": "Mariner 9 Television Calibration\u2014Revisited", "author": [ { "family_name": "Herkenhoff", "given_name": "Ken E.", "orcid": "0000-0002-3153-6663", "clpid": "Herkenhoff-K-E" }, { "family_name": "Soderblom", "given_name": "Laurence A.", "orcid": "0000-0002-0917-853X", "clpid": "Soderblom-L-A" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Danielson", "given_name": "G. Edward", "clpid": "Danielson-G-E" } ], "abstract": "Improved processing of the Mariner 9 Television data allows more accurate photometric analysis of the images returned in 1971\u20131972 by the first successful Mars-orbiting spacecraft. These data include good synoptic coverage of the planet and the highest resolution images yet obtained of the south polar region. Errors in calibration are comparable to (but still greater than) those of the Viking orbiter cameras. Calibration data and software are now available to interested parties as part of the Planetary Image Cartography System through the U.S. Geological Survey in Flagstaff, Arizona.", "doi": "10.1016/0019-1035(88)90132-7", "issn": "0019-1035", "publisher": "Elsevier", "publication": "Icarus", "publication_date": "1988-07", "series_number": "1", "volume": "75", "issue": "1", "pages": "133-145" }, { "id": "authors:90t4e-kjb82", "collection": "authors", "collection_id": "90t4e-kjb82", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-142004185", "type": "article", "title": "The Formation of Mercury's Smooth Plains", "author": [ { "family_name": "Kiefer", "given_name": "Walter S.", "clpid": "Kiefer-W-S" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "There has been extensive debate about whether Mercury's smooth plains are volcanic features or impact ejecta deposits. We present new indirect evidence which supports a volcanic origin for two different smooth plains units. In Borealis Planitia, stratigraphic relations indicate at least two distinct stages of smooth plains formation. At least one of these stages must have had a volcanic origin. In the Hilly and Lineated Terrain, Petrarch and several other anomalously shallow craters apparently have been volcanically filled. Areally extensive smooth plains volcanism evidently occurred at these two widely separated areas on Mercury. These results, combined with work by other researchers on the circum-Caloris plains and the Tolstoi basin, show that smooth plains volcanism was a global process on Mercury. Present data suggest to us that the smooth and intercrater plains may represent two distinct episodes of volcanic activity on Mercury and that smooth plains volcanism may have been triggered by the Caloris impact. High-resolution and multispectral imaging from a future Mercury spacecraft could resolve many of the present uncertainties in our understanding of plains formation on Mercury.", "doi": "10.1016/0019-1035(87)90046-7", "issn": "0019-1035", "publisher": "Elsevier", "publication": "Icarus", "publication_date": "1987-12", "series_number": "3", "volume": "72", "issue": "3", "pages": "477-491" }, { "id": "authors:5jwze-yss48", "collection": "authors", "collection_id": "5jwze-yss48", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-111830732", "type": "article", "title": "\"Born Anew\" versus \"Born Again\"", "author": [ { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" } ], "abstract": "Albert D. Wheelon's thoughtful analysis, originally presented July 15, 1986, establishes many crucial points. First, NASA's total concentration on a \"Shuttle-only\" program led to the disastrous current state of the United States' space program. Wheelon is right in stating that the United States must now use its disarray to good purpose by restructuring the national space program to use the \nShuttle and its astronauts solely for those activities that genuinely require the presence of humans in space.", "issn": "0162-2889", "publisher": "MIT Press", "publication": "International Security", "publication_date": "1987-03", "series_number": "4", "volume": "11", "issue": "4", "pages": "178-182" }, { "id": "authors:jtbqk-6k850", "collection": "authors", "collection_id": "jtbqk-6k850", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140409-110112247", "type": "article", "title": "D\u00e9tente in Space", "author": [ { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" }, { "family_name": "Davies", "given_name": "Merton E.", "clpid": "Davies-M-E" } ], "abstract": "The space programs of the United States and Soviet Union have been bound together for nearly two decades through rivalry, competition, and, most recently, cooperation. The scientific consequences of these space activities have been to revolutionize the study of the solar system, to open the high-energy (x-ray, gamma ray, and cosmic ray) window to astrophysical observation, and to significantly influence the study of Earth itself, especially its atmosphere. Nevertheless, scientific research in itself never has been the principal justification for space expenditures.", "doi": "10.1126/science.192.4244.1067", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1976-06-11", "series_number": "4244", "volume": "192", "issue": "4244", "pages": "1067-1074" }, { "id": "authors:bde6b-p1f16", "collection": "authors", "collection_id": "bde6b-p1f16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140410-162355670", "type": "article", "title": "Surface History of Mercury: Implications for Terrestrial Planets", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Strom", "given_name": "Robert G.", "clpid": "Strom-R-G" }, { "family_name": "Trask", "given_name": "Newell J.", "clpid": "Trask-N-J" }, { "family_name": "Gault", "given_name": "Donald E.", "clpid": "Gault-D-E" } ], "abstract": "A working hypothesis of Mercury's history is presented. We infer the surface of Mercury to record a sequence of events broadly similar to those recorded on the moon, implying similar histories of impact bombardment. The oldest terrain so n Mercury seem to be better preserved from modification by ejecta from subsequently formed impact basins because of higher surface gravity. The large lunarlike impact craters on Mercury can be interpreted as part of a distinct episode of bombardment which may have affected all the terrestrial planets about 4 b.y. ago. The light cratering accumulated on the surfaces of the\nMercurian smooth plains is similar in diameter/frequency relationship to that of the lunar maria and of the oldest Martian plains units, consistent with recent interpretations of lunar and Martian flux histories by Wetherill(1974) and Soderblom et al. (1974). A straightforward interpretation of the Mercurian surface record thus supports recent order of magnitude increases in age estimates of many Martian\nfeatures discovered by Mariner 9 but is not conclusive. The large core inferred for Mercury combined with the lack of recognizable evidence of past atmospheric activity is more easily understood in terms of radially heterogeneous accumulation than in terms of differentiation of a homogeneous planet. Early core cooling may be reflected by widespread evidence of crustal shortening. However, Mercury's surface seems little affected by any tectonic, atmospheric, or volcanic processes for the last 3 b.y. or so, raising questions concerning (1) the relationship of the origin of Mercury's magnetic field to that of earth's and (2) the primary cause of volcanic flooding, which may have begun, and ended, approximately synchronously on Mercury and the moon.", "doi": "10.1029/JB080i017p02508", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research B", "publication_date": "1975-06-10", "series_number": "17", "volume": "80", "issue": "17", "pages": "2508-2514" }, { "id": "authors:rhv4w-s0639", "collection": "authors", "collection_id": "rhv4w-s0639", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141106-150936559", "type": "article", "title": "Preliminary imaging results from the second Mercury encounter", "author": [ { "family_name": "Strom", "given_name": "Robert G.", "clpid": "Strom-R-G" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Belton", "given_name": "Michael J. S.", "clpid": "Belton-M-J-S" }, { "family_name": "Danielson", "given_name": "G. Edward", "clpid": "Danielson-G-E" }, { "family_name": "Davies", "given_name": "Merton E.", "clpid": "Davies-M-E" }, { "family_name": "Gault", "given_name": "Donald E.", "clpid": "Gault-D-E" }, { "family_name": "Hapke", "given_name": "Bruce", "clpid": "Hapke-B" }, { "family_name": "O'Leary", "given_name": "Brian", "clpid": "O'Leary-B" }, { "family_name": "Trask", "given_name": "Newell", "clpid": "Trask-N-J" }, { "family_name": "Guest", "given_name": "John E.", "clpid": "Guest-J-E" }, { "family_name": "Anderson", "given_name": "James", "clpid": "Anderson-J" }, { "family_name": "Klaasen", "given_name": "Kenneth", "clpid": "Klaasen-K-P" } ], "abstract": "The second Mercury encounter has resulted in the acquisition of about 360 pictures of the south polar regions which provide a reliable cartographic and geologic tie between the two sides of the planet photographed on the first encounter. Stereoscopic coverage of large areas of the southern hemisphere was obtained by combining Mercury 1 and 2 pictures taken at different viewing angles. The south polar regions consist of heavily cratered terrain and intercrater plains interspersed with patches of smooth plains. No large areas of smooth plains similar to those surrounding Caloris occur in the south polar regions. No new types of terrain have been recognized, but lobate scarps are common. The second largest basin seen by Mariner 10 (\u223c600-km diameter) has been confirmed on the new photography. At high solar elevations the surface displays an abundance of rays and rayed craters.", "doi": "10.1029/JB080i017p02345", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1975-06-10", "series_number": "17", "volume": "80", "issue": "17", "pages": "2345-2356" }, { "id": "authors:fxjdv-8pw24", "collection": "authors", "collection_id": "fxjdv-8pw24", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20140414-124525538", "type": "article", "title": "The Mariner 10 Pictures of Mercury: An Overview", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "The 11 papers in this issue, comprising the Mariner 10 imaging team final report, are brought together,\nand the salient results of the Mariner 10 imaging experiment at Mercury are summarized. Those aspects of\nthe data set acquired which were worked by the team are identified, and other areas where further work is\nneeded are designated.", "doi": "10.1029/JB080i017p02342", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research B", "publication_date": "1975-06-10", "series_number": "17", "volume": "80", "issue": "17", "pages": "2342-2344" }, { "id": "authors:m411m-80t56", "collection": "authors", "collection_id": "m411m-80t56", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141105-154055524", "type": "article", "title": "Climatic variations on Mars: 2. Evolution of carbon dioxide atmosphere and polar caps", "author": [ { "family_name": "Ward", "given_name": "William R.", "clpid": "Ward-W-R" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Malin", "given_name": "Michael C.", "clpid": "Malin-M-C" } ], "abstract": "The long-term variations in the atmospheric pressure and the polar cap temperature of Mars resulting from the obliquity oscillations (presented by W. R. Ward, 1974) are discussed. In performing these calculations, the assumption is made that the atmosphere is in equilibrium with perennial CO_2 ice deposits at the north pole, as is proposed by R. B. Leighton and B. C. Murray (1966). If heat transport by the atmosphere is neglected, the temperature of CO_2 ice at the poles ranges from \u223c130\u00b0K to \u223c160\u00b0K, the corresponding atmospheric pressure rising from a few tenths of a millibar to \u223c30 mbar, respectively. The neglect of atmospheric heat transport probably underestimates the peak pressure. Because the altitude of the south cap is \u223c2 km higher than that of the north cap, CO_2 ice is unstable there and will migrate to the north cap at a rate \u223c10 g/cm^2 yr, the implication being that the south residual cap is water ice. A simplified model of the annual polar caps and pressure fluctuations is also presented. This indicates that when the obliquity is at its maximum, the annual caps may be greatly enlarged in both mass and maximum coverage. The modifications introduced by including significant atmospheric heat transport are then discussed. Finally, the implications of different past climatic conditions on the mechanism of eolian erosion are briefly considered.", "doi": "10.1029/JC079i024p03387", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1974-08-20", "series_number": "24", "volume": "79", "issue": "24", "pages": "3387-3395" }, { "id": "authors:ayq1a-h7a94", "collection": "authors", "collection_id": "ayq1a-h7a94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151112-082856291", "type": "article", "title": "Mercury's Surface: Preliminary Description and Interpretation from Mariner 10 Pictures", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Belton", "given_name": "Michael J. S.", "clpid": "Belton-M-J-S" }, { "family_name": "Danielson", "given_name": "G. Edward", "clpid": "Danielson-G-E" }, { "family_name": "Davies", "given_name": "Merton E.", "clpid": "Davies-M-E" }, { "family_name": "Gault", "given_name": "Donald E.", "clpid": "Gault-D-E" }, { "family_name": "Hapke", "given_name": "Bruce", "clpid": "Hapke-B" }, { "family_name": "O'Leary", "given_name": "Brian", "clpid": "O'Leary-B" }, { "family_name": "Strom", "given_name": "Robert G.", "clpid": "Strom-R-G" }, { "family_name": "Suomi", "given_name": "Verner", "clpid": "Suomi-V-E" }, { "family_name": "Trask", "given_name": "Newell", "clpid": "Trask-N-J" } ], "abstract": "The surface morphology and optical properties of Mercury resemble those of the moon in remarkable detail and record a very similar sequence of events. Chemical and mineralogical similarity of the outer layers of Mercury and the moon is implied; Mercury is probably a differentiated planet with a large iron-rich core. Differentiation is inferred to have occurred very early. No evidence of atmospheric modification of landforms has been found. Large-scale scarps and ridges unlike lunar or martian features may reflect a unique period of planetary compression near the end of heavy bombardment by small planetesimals.", "doi": "10.1126/science.185.4146.169", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1974-07-12", "series_number": "4146", "volume": "185", "issue": "4146", "pages": "169-179" }, { "id": "authors:z392p-sym84", "collection": "authors", "collection_id": "z392p-sym84", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151112-114911743", "type": "article", "title": "Mariner 10 Pictures of Mercury: First Results", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Belton", "given_name": "Michael J. S.", "clpid": "Belton-M-J-S" }, { "family_name": "Danielson", "given_name": "G. Edward", "clpid": "Danielson-G-E" }, { "family_name": "Davies", "given_name": "Merton E.", "clpid": "Davies-M-E" }, { "family_name": "Gault", "given_name": "Donald", "clpid": "Gault-D-E" }, { "family_name": "Hapke", "given_name": "Bruce", "clpid": "Hapke-B" }, { "family_name": "O'Leary", "given_name": "Brian", "clpid": "O'Leary-B" }, { "family_name": "Strom", "given_name": "Robert G.", "clpid": "Strom-R-G" }, { "family_name": "Suomi", "given_name": "Verner", "clpid": "Suomi-V-E" }, { "family_name": "Trask", "given_name": "Newell", "clpid": "Trask-N-J" } ], "abstract": "Mercury has a heavily cratered surface containing basins up to at least 1300 kilometers diameter flooded with mare-like material. Many features are closely similar to those on the moon, but significant structural differences exist. Major chemical differentiation before termination of accretion is implied.", "doi": "10.1126/science.184.4135.459", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1974-04-26", "series_number": "4135", "volume": "184", "issue": "4135", "pages": "459-461" }, { "id": "authors:pv9rx-aef16", "collection": "authors", "collection_id": "pv9rx-aef16", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151112-122053233", "type": "article", "title": "Venus: Atmospheric Motion and Structure from Mariner 10 Pictures", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Belton", "given_name": "Michael J. S.", "clpid": "Belton-M-J-S" }, { "family_name": "Danielson", "given_name": "G. Edward", "clpid": "Danielson-G-E" }, { "family_name": "Davies", "given_name": "Merton E.", "clpid": "Davies-M-E" }, { "family_name": "Gault", "given_name": "Donald", "clpid": "Gault-D-E" }, { "family_name": "Hapke", "given_name": "Bruce", "clpid": "Hapke-B" }, { "family_name": "O'Leary", "given_name": "Brian", "clpid": "O'Leary-B" }, { "family_name": "Strom", "given_name": "Robert G.", "clpid": "Strom-R-G" }, { "family_name": "Suomi", "given_name": "Verner", "clpid": "Suomi-V-E" }, { "family_name": "Trask", "given_name": "Newell", "clpid": "Trask-N-J" } ], "abstract": "The Mariner 10 television cameras imaged the planet Venus in the visible and near ultraviolet for a period of 8 days at resolutions ranging from 100 meters to 130 kilometers. The general pattern of the atmospheric circulation in the upper tropospheric/lower stratospheric region is displayed in the pictures. Atmospheric flow is symmetrical between north and south hemispheres. The equatorial motions are zonal (east-west) at approximately 100 meters per second, consistent with the previously inferred 4-day retrograde rotation. Angular velocity increases with latitude. The subsolar region, and the region downwind from it, show evidence of large-scale convection that persists in spite of the main zonal motion. Dynamical interaction between the zonal motion and the relatively stationary region of convection is evidenced by bowlike waves.", "doi": "10.1126/science.183.4131.1307", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1974-03-29", "series_number": "4131", "volume": "183", "issue": "4131", "pages": "1307-1315" }, { "id": "authors:srsqd-sbb54", "collection": "authors", "collection_id": "srsqd-sbb54", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20150225-084343133", "type": "article", "title": "Polar Volatiles on Mars\u2014Theory versus Observation - \n Excess solid carbon dioxide is probably present in the north residual cap", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Malin", "given_name": "Michael C.", "clpid": "Malin-M-C" } ], "abstract": "The residual frost caps of Mars are probably water-ice. They may be the source of the water vapor associated with seasonal polar hoods. A permanent reservoir of solid CO_2 is also probably present within the north residual cap and may comprise a mass of CO_2 some two to five times that of the present atmosphere of Mars. The martian atmospheric pressure is probably regulated by the temperature of the reservoir and not by the annual heat balance of exposed solid CO_2 (37). The present reservoir temperature presumably reflects a long-term average of the polar heat balance.\nThe question of a large permanent north polar cap is reexamined in light of the Mariner 9 data. The lower general elevation of the north polar region compared to the south and the resulting occurrence in the north of a permanent CO_2 deposit are probably responsible for the differences in size and shape of the two residual caps. The details of the processes involved are less apparent, however. It might be argued that the stability of water-ice deposits depends on both insolation and altitude. The present north and south residual caps should be symmetrically located with respect to such a hypothetical stability field. However, the offset of the south cap from the geometrical pole, the non-symmetrical outline of the north cap, and the apparently uniform thickness of the thin, widespread water-ice all argue against control by simple solid-vapor equilibrium of water under present environmental conditions. We think that the present location of the water-ice may reflect, in part, the past location of the permanent CO_2 reservoir. The extreme stability of polar water-ice deposits increases the likelihood that past environmental conditions may be recorded there. Detailed information on elevations in the vicinity of the residual caps is needed before we can further elucidate the nature and history of the residual caps. This, along with measurements of polar infrared emission, should be given high priority in future missions to Mars.\nTwo conclusions follow from the limitation of the mass of solid CO_2 on Mars at present to two to five times the mass of CO_2 in the atmosphere. If all of this CO_2 was entirely sublimated into the atmosphere as a result of hypothetical astronomical or geophysical effects, the average surface pressure would increase to 15 to 30 mbar. Although such a change would have considerable significance for eolian erosion and transportation, there seems to be little possibility that a sufficiently earthlike atmosphere could result for liquid water to become an active erosional agent, as postulated by Milton (38). The pressure broadening required for a green-house effect requires at least 10 to 20 times more pressure (39). If liquid water was ever active in modifying the martian surface, it must have been at an earlier epoch, before the present, very stable CO_2/H_2O system developed. There can be no intermittent earthlike episodes now.\nFurthermore, the present abundance of CO_2 on Mars may be an indicator of the cumulative evolution of volatiles to the surface of the planet (40). Thus, even the possibility of an earlier earth-like episode is dimmed. On Mars, the total CO_2 definitely outgassed has evidently been about 60 \u00b1 20 g/cm^2. On the earth, about 70 \u00b1 30 kg/cm^2 of CO_2 have been released to the surface (41). Hence, the total CO_2 devolved by Mars per unit area is about 0.1 percent of that evolved by the earth. Thus, the observational limits we place on solid CO_2 presently located under the north residual cap also may constitute considerable constraints on the total differentiation and devolatilization of the planet. If they are valid, it would seem unlikely that Mars has devolatilized at all like the earth, or ever experienced an earthlike environment on its surface.", "doi": "10.1126/science.182.4111.437", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1973-11-02", "series_number": "4111", "volume": "182", "issue": "4111", "pages": "437-443" }, { "id": "authors:gy3ec-pfh96", "collection": "authors", "collection_id": "gy3ec-pfh96", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151111-100012991", "type": "article", "title": "Periodic Insolation Variations on Mars", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Ward", "given_name": "William R.", "clpid": "Ward-W-R" }, { "family_name": "Yeung", "given_name": "Sze C.", "clpid": "Yeung-Sze-C" } ], "abstract": "Previously unrecognized insolation variations on Mars are a consequence of periodic variations in eccentricity, first established by the theory of Brouwer and Van Woerkom (1950). Such annual insolation variations, characterized by both 95,000-year and 2,000,000-year periodicities, may actually be recorded in newly discovered layered deposits in the polar regions of Mars. An additional north-south variation in seasonal insolation, but not average annual insolation, exists with 51,000-year and 2,000,000-year periodicities.", "doi": "10.1126/science.180.4086.638", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1973-05-11", "series_number": "4086", "volume": "180", "issue": "4086", "pages": "638-640" }, { "id": "authors:a6yjk-3dg98", "collection": "authors", "collection_id": "a6yjk-3dg98", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151111-100012740", "type": "article", "title": "Polar Wandering on Mars?", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Malin", "given_name": "Michael C.", "clpid": "Malin-M-C" } ], "abstract": "Polar wandering during the past 10^8 years may be recorded by unique quasi-circular structures in the polar regions of Mars. Polar wandering on Mars is likely if deep convection is involved in the origin of the very large constructional volcanic features located near the equator. The magnitude of the nonhydrostatic low order components of the gravity field and their correlation with the equatorial volcanic features may be additional evidence of deep convection and associated polar wandering.", "doi": "10.1126/science.179.4077.997", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1973-03-09", "series_number": "4077", "volume": "179", "issue": "4077", "pages": "997-1000" }, { "id": "authors:6bgxq-n4311", "collection": "authors", "collection_id": "6bgxq-n4311", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151111-095217192", "type": "article", "title": "The UFO Experience. A Scientific Inquiry. [Book Review]", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "If there's one thing harder than writing a responsible book about Unidentified Flying Objects, it's writing a meaningful review of such a book without being drawn into the controversy. I have the uneasy feeling that Hynek has been more successful in his task than I shall be in mine. Hynek's book is more than just an attempt to justify scientific interest in UFO phenomena. It is, in fact, Hynek's version of what the Condon report (1) should have been, interlaced with stinging criticism of the study on which it reported.", "doi": "10.1126/science.177.4050.688", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1972-08-25", "series_number": "4050", "volume": "177", "issue": "4050", "pages": "688-689" }, { "id": "authors:w0de6-6ys58", "collection": "authors", "collection_id": "w0de6-6ys58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151111-080331134", "type": "article", "title": "Mariner 9 Television Reconnaissance of Mars and Its Satellites: Preliminary Results", "author": [ { "family_name": "Masursky", "given_name": "Harold", "clpid": "Masursky-H" }, { "family_name": "Murray", "given_name": "B. C.", "clpid": "Murray-B-C" }, { "family_name": "Cutts", "given_name": "J. A.", "orcid": "0000-0002-1765-8322", "clpid": "Cutts-J-A" }, { "family_name": "Sharp", "given_name": "R. P.", "clpid": "Sharp-R-P" }, { "family_name": "Smith", "given_name": "Susan", "clpid": "Smith-S" }, { "family_name": "Leighton", "given_name": "R. B.", "clpid": "Leighton-R-B" }, { "family_name": "Sagan", "given_name": "C.", "clpid": "Sagan-C" } ], "abstract": "At orbit insertion on 14 November 1971 the Martian surface was largely obscured by a dust haze with an extinction optical depth that ranged from near unity in the south polar region to probably greater than 2 over most of the planet. The only features clearly visible were the south polar cap, one dark, spot in Nix Olympica, and three dark spots in the Tharsis region. During the third week the atmosphere began to clear and surface visibility improved, but contrasts remained a fraction of their normal value. Each of the dark spots that apparently protrude through most of the dust-filled atmosphere has a crater or crater complex in its center. The craters are rimless and have featureless floors that, in the crater complexes, are at different levels. The largest crater within the southernmost spot is approximately 100 kilometers wide. The craters apparently were formed by subsidence and resemble terrestrial calderas. The south polar cap has a regular margin, suggesting very flat topography. Two craters outside the cap have frost on their floors; an apparent crater rim within the cap is frost free, indicating preferential loss of frost from elevated ground. If this is so then the curvilinear streaks, which were frost covered in 1969 and are now clear of frost, may be low-relief ridges. Closeup pictures of Phobos and Deimos show that Phobos is about 25 \u00b15 by 21 \u00b11 kilometers and Deimos is about 13.5 \u00b1 2 by 12.0 \u00b10.5 kilometers. Both have irregular shapes and are highly cratered, with some craters showing raised rims. The satellites are dark objects with geometric albedos of 0.05.", "doi": "10.1126/science.175.4019.294", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1972-01-21", "series_number": "4019", "volume": "175", "issue": "4019", "pages": "294-305" }, { "id": "authors:3me89-j9a71", "collection": "authors", "collection_id": "3me89-j9a71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141107-100311498", "type": "article", "title": "One year's processing and interpretation \u2014 An overview", "author": [ { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "A total of 201 complete television frames of Mars were returned by Mariners 6 and 7 in late July and early August of 1969. During the subsequent year over 3500 different versions of those frames were generated by computer processing involving the production of about 35,000 individual photographic prints and large amounts of computer printout as well. This extensive data processing and distribution required the significant participation of about fifteen scientists, engineers, and technicians, mainly at the Jet Propulsion Laboratory. During that same year, the processed data were analyzed and interpreted by approximately twenty-five scientists and technicians at six different institutions. The special supplement of which this is the introductory paper presents most of the scientific findings that have accrued during the first year following the Mariner 6 and 7 flybys of Mars. It constitutes a final report on the television experiment, although significant efforts are continuing. Preliminary results were presented in three papers published in August and October of 1969 [Leighton et al., 1969a, b, c]. Smith [1970] presented information about the size, shape, and surprisingly low albedo of the martian satellite Phobos. Information concerning various aspects of the camera and data systems has also been published recently [Danielson, 1970].", "doi": "10.1029/JB076i002p00293", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1971-01-10", "series_number": "2", "volume": "76", "issue": "2", "pages": "293-296" }, { "id": "authors:gmgjc-sst07", "collection": "authors", "collection_id": "gmgjc-sst07", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141107-093416204", "type": "article", "title": "The surface of Mars 1. Cratered terrains", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Soderblom", "given_name": "Laurence A.", "orcid": "0000-0002-0917-853X", "clpid": "Soderblom-L-A" }, { "family_name": "Sharp", "given_name": "Robert P.", "clpid": "Sharp-R-P" }, { "family_name": "Cutts", "given_name": "James A.", "orcid": "0000-0002-1765-8322", "clpid": "Cutts-J-A" } ], "abstract": "Mariner 6 and 7 pictures show that craters are the dominant landform on Mars and that their occurrence is not correlated uniquely with latitude, elevation, or albedo markings. Two distinct morphological classes are recognized: small bowl-shaped and large flat-bottomed. The former show little evidence of modifications, whereas the latter appear generally more modified than lunar upland craters of comparable size. A regional maria/uplands dichotomy like the moon has not yet been recognized on Mars. Crater modification on Mars has involved much greater horizontal redistribution of material than in the lunar uplands. It is possible that there are erosional processes only infrequently active. Analysis of the natures and fluxes of bodies that have probably impacted the moon and Mars leads to the likelihood that most of the large flat-bottomed craters on Mars have survived from the final phases of planetary accretion. Significant crater modification, however, has taken place more recently on Mars. Inasmuch as the present small bowl-shaped craters evidence little modification, the postaccretion crater-modification process on Mars may have been primarily episodic rather than continuous. The size-frequency distribution of impacting bodies that produced the present small Martian bowl-shaped craters differs from that responsible for post-mare primary impacts on the moon by a marked deficiency of large bodies. Survival of crater topography from the end of planetary accretion would make any hypothetical earthlike phase with primitive oceans there unlikely. The traditional view of Mars as an earthlike planetary neighbor in terms of its surface history is not supported by the picture data.", "doi": "10.1029/JB076i002p00313", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1971-01-10", "series_number": "2", "volume": "76", "issue": "2", "pages": "313-330" }, { "id": "authors:c3p5f-r6g29", "collection": "authors", "collection_id": "c3p5f-r6g29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141107-092332375", "type": "article", "title": "The surface of Mars 3. Light and dark markings", "author": [ { "family_name": "Cutts", "given_name": "James A.", "orcid": "0000-0002-1765-8322", "clpid": "Cutts-J-A" }, { "family_name": "Soderblom", "given_name": "Laurence A.", "orcid": "0000-0002-0917-853X", "clpid": "Soderblom-L-A" }, { "family_name": "Sharp", "given_name": "Robert P.", "clpid": "Sharp-R-P" }, { "family_name": "Smith", "given_name": "Bradford A.", "clpid": "Smith-B-A" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "The Mariner 6 and 7 pictures have provided significant clues to the nature of the light and dark markings on Mars, but do not yet provide an adequate foundation for any complete explanation of the phenomena. They display detail never before seen or photographed and demonstrate that there is no network of dark lines (i.e. canals) on the planet. A variety of shapes and of boundaries between major markings are recorded in the pictures. No substantial correlation of albedo markings with cratered or chaotic terrain has been recognized; featureless terrain conceivably may be genetically related to light areas. Within and surrounding the dark area Meridiani Sinus there is evidence of local topographic control of albedo markings; light material is found in locally low areas. Also, characteristic patterns of local albedo markings are exhibited by craters there. Aeolian transportation of light material with deposition locally in low areas is suggested as an explanation of these markings and may be useful as a working hypothesis for subsequent exploration. Across some light/dark boundaries crater morphologies are unchanged; across others craters in the light area appear smoother. If there is a relationship between cratered terrain modification and surface albedo it is an indirect one.", "doi": "10.1029/JB076i002p00343", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1971-01-10", "series_number": "2", "volume": "76", "issue": "2", "pages": "343-356" }, { "id": "authors:pkh7r-19b29", "collection": "authors", "collection_id": "pkh7r-19b29", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141107-090849160", "type": "article", "title": "The surface of Mars 4. South polar cap", "author": [ { "family_name": "Sharp", "given_name": "Robert P.", "clpid": "Sharp-R-P" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Soderblom", "given_name": "Laurence A.", "orcid": "0000-0002-0917-853X", "clpid": "Soderblom-L-A" }, { "family_name": "Cutts", "given_name": "James A.", "orcid": "0000-0002-1765-8322", "clpid": "Cutts-J-A" } ], "abstract": "The south polar cap of Mars occupies a region of cratered terrain. Immediately outside the shrinking cap craters appear no more modified than those in areas farther north that are not annually frost covered. Craters showing through the frost mantle are locally as abundant as elsewhere on Mars. Only in a central region close to the pole are craters sparse. Both far- and near-encounter views reveal a highly irregular pole-cap edge. Photos of the same sector taken six days apart are near duplicates, suggesting that the irregularity is primarily ground controlled. No evidence of the classical polar collar is seen. Within the marginal zone, frost is preserved largely in crater bottoms and on slopes inclined away from the sun. Preferential retention in low spots supports the earlier suggestion that the Mountains of Mitchel may actually be depressions. An argument based on insolation as the prime factor in frost wastage and the narrow width of the marginal zone suggests that slopes of topographic features therein are mostly gentle, on the order of a few degrees. The frost cover of the pole-cap interior may range widely in thickness, obscuring parts of some craters and seemingly enhancing topographic visibility elsewhere, possibly through variations in thickness and reflectivity. Unusually bright areas on the cap surface, and differences in luminance between bright rims and the more somber floors of craters and other depressions, may be due in large part to differences in related frost textures and to the local history of evaporation and sublimation. Irregularly angular depressions within the polecap frost termed 'etch pits' may be the product of differential ablation or the undermining by wind of a slabby surficial crust. Encircling the south pole is a region of subdued relief with a paucity of craters, which displays enigmatic quasi-linear markings believed to be ground features. Although no satisfactory explanation of these markings has been formulated, it seems likely that this region has been occupied repeatedly by perennial masses of CO_2 ice, formed and maintained during those phases of the martian precessional cycle that resulted in short cool summers in the southern hemisphere. Such ice masses may play a role in producing the unusual features of the central polar region. Physical relationships suggest a local maximum frost thickness as great as tens of meters. The possibility should be kept in mind that remnants of perennial CO_2 ice of still greater thickness may exist locally, for example, in the 'etch pit' area.", "doi": "10.1029/JB076i002p00357", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1971-01-10", "series_number": "2", "volume": "76", "issue": "2", "pages": "357-368" }, { "id": "authors:ckcrk-d4j33", "collection": "authors", "collection_id": "ckcrk-d4j33", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141107-092830228", "type": "article", "title": "The surface of Mars 2. Uncratered terrains", "author": [ { "family_name": "Sharp", "given_name": "Robert P.", "clpid": "Sharp-R-P" }, { "family_name": "Soderblom", "given_name": "Laurence A.", "orcid": "0000-0002-0917-853X", "clpid": "Soderblom-L-A" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Cutts", "given_name": "James A.", "orcid": "0000-0002-1765-8322", "clpid": "Cutts-J-A" } ], "abstract": "Mariner 6 and 7 photographs reveal two types of uncratered terrain on Mars. These are descriptively termed chaotic and featureless. Chaotic terrain is younger than cratered terrain and displays features strongly suggestive of slump and collapse. The speculation is offered that it may be an expression of geothermal developments within Mars that only recently have begun to affect the surface. Featureless terrain, identified only within the large circular area Hellas, is devoid of any discernible topographic forms larger than the limit of resolution, about 500 meters. Manner 7 data indicate that Hellas is a topographically low and structurally old basin. Smoothness of its floor could be the product of a recent event or of continuous processes that obliterate craters. Local processes of high efficacy, unusual surface materials, or both, are probably involved. Through its chaotic terrain the martian surface displays a development that does not seem to be recorded, at least in the form of preserved recognizable evidence, on the moon or earth.", "doi": "10.1029/JB076i002p00331", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1971-01-10", "series_number": "2", "volume": "76", "issue": "2", "pages": "331-342" }, { "id": "authors:5h0a6-trf20", "collection": "authors", "collection_id": "5h0a6-trf20", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:MURao70", "type": "article", "title": "Space photography and the exploration of Mars", "author": [ { "family_name": "Murray", "given_name": "B. C.", "clpid": "Murray-B-C" }, { "family_name": "Davies", "given_name": "M. E.", "clpid": "Davies-M-E" } ], "abstract": "A general exposition of the scientific potentialities and analytic framework of space photography is presented using the photography of Mars from flybys and orbiters as the principal example. Space photography is treated here as a communication process in which planetary scene information is communicated to the eye-brain receiver of earth-based interpreters. The salient parameters of this process are: (1) total information returned, (2) surface resolution, and (3) a priori knowledge regarding the planetary surface observed.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1970-06", "series_number": "6", "volume": "9", "issue": "6", "pages": "1270-1281" }, { "id": "authors:6g8cj-ht668", "collection": "authors", "collection_id": "6g8cj-ht668", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151214-082238288", "type": "article", "title": "Mariner 6 and 7 Television Pictures: Preliminary Analysis", "author": [ { "family_name": "Leighton", "given_name": "R. B.", "clpid": "Leighton-R-B" }, { "family_name": "Horowitz", "given_name": "N. H.", "clpid": "Horowitz-N-H" }, { "family_name": "Murray", "given_name": "B. C.", "clpid": "Murray-B-C" }, { "family_name": "Sharp", "given_name": "R. P.", "clpid": "Sharp-R-P" }, { "family_name": "Herriman", "given_name": "A. H.", "clpid": "Herriman-Alan-H" }, { "family_name": "Young", "given_name": "A. T.", "clpid": "Young-Andrew-T" }, { "family_name": "Smith", "given_name": "B. A.", "clpid": "Smith-Bradford-A" }, { "family_name": "Davies", "given_name": "M. E.", "clpid": "Davies-Merton-E" }, { "family_name": "Leovy", "given_name": "C. B.", "clpid": "Leovy-Conway-B" } ], "abstract": "Before the space era, Mars was\nthought to be like the earth; after Mariner\n4, Mars seemed to be like the moon;\nMariners 6 and 7 have shown Mars to\nhave its own distinctive features, unknown\nelsewhere within the solar\nsystem.", "doi": "10.1126/science.166.3901.49", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1969-10-03", "series_number": "3901", "volume": "166", "issue": "3901", "pages": "49-67" }, { "id": "authors:d6ygq-2kt05", "collection": "authors", "collection_id": "d6ygq-2kt05", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141210-085120083", "type": "article", "title": "Mariner 7 Television Pictures: First Report", "author": [ { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Horowitz", "given_name": "Norman H.", "clpid": "Horowitz-N-H" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Sharp", "given_name": "Robert P.", "clpid": "Sharp-R-P" }, { "family_name": "Herriman", "given_name": "Alan G.", "clpid": "Herriman-Alan-G" }, { "family_name": "Young", "given_name": "Andrew T.", "clpid": "Young-Andrew-T" }, { "family_name": "Smith", "given_name": "Bradford A.", "clpid": "Smith-Bradford-A" }, { "family_name": "Davies", "given_name": "Merton E.", "clpid": "Davies-Merton-E" }, { "family_name": "Leovy\u00ad", "given_name": "Conway B.", "clpid": "Leovy-Conway-B" } ], "abstract": "Initial results of the television experiment\ncarried by Mariner 6 were recently\nreported (1). This is a similar\nreport of the television experiment\naboard Mariner 7. These reports are\npresented primarily to communicate\nsignificant results to the scientific community\nas rapidly as possible. A more\ncomprehensive, but still preliminary,\nreview of the results of both experiments,\nand of their implications concerning\nthe atmosphere and surface of\nMars, is in preparation for submission\nto this journal.", "doi": "10.1126/science.165.3895.787", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1969-08-22", "series_number": "3895", "volume": "165", "issue": "3895", "pages": "787-795" }, { "id": "authors:a4f1h-2s238", "collection": "authors", "collection_id": "a4f1h-2s238", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151214-083812476", "type": "article", "title": "Mariner 6 Television Pictures: First Report", "author": [ { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Horowitz", "given_name": "Norman H.", "clpid": "Horowitz-N-H" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Sharp", "given_name": "Robert P.", "clpid": "Sharp-R-P" }, { "family_name": "Herriman", "given_name": "Alan G.", "clpid": "Herriman-Alan-G" }, { "family_name": "Young", "given_name": "Andrew T.", "clpid": "Young-Andrew-T" }, { "family_name": "Smith", "given_name": "Bradford A.", "clpid": "Smith-Bradford-A" }, { "family_name": "Davies", "given_name": "Merton E.", "clpid": "Davies-Merton-E" }, { "family_name": "Leovy\u00ad", "given_name": "Conway B.", "clpid": "Leovy-Conway-B" } ], "abstract": "In July 1965, Mariner 4 flew past\nMars and recorded 20 television pictures\nof the martian surface; the principal\ntelevision result of that pioneering\nflight was the discovery that Mars' surface\nis heavily cratered and resembles\nthe Moon more than it does the Earth\n(1). On 31 July 1969, the more advanced\nMariner 6 spacecraft, carrying\ntwo television cameras, passed Mars\nand recorded 75 pictures. A twin spacecraft,\nMariner 7, passed Mars on 5\nAugust 1969. This report summarizes\nthe results of a first, qualitative study\nof the Mariner 6 television pictures,\ncarried out on the uncalibrated data\nwithin a few days after receipt on\nEarth.", "doi": "10.1126/science.165.3894.685", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1969-08-15", "series_number": "3894", "volume": "165", "issue": "3894", "pages": "685-690" }, { "id": "authors:8yy4j-y2d74", "collection": "authors", "collection_id": "8yy4j-y2d74", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141107-121440929", "type": "article", "title": "Differences between proposed Apollo sites: 1. Synthesis", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Goetz", "given_name": "Alexander F. H.", "clpid": "Goetz-A-F-H" }, { "family_name": "Kieffer", "given_name": "Hugh H.", "clpid": "Kieffer-H-H" }, { "family_name": "McCord", "given_name": "Thomas B.", "clpid": "McCord-T-B" } ], "abstract": "Recent observations of the spectral reflectivity and emissivity of the five prime Apollo landing sites are evaluated in the context of similar observations of other localities on the moon and of data returned from unmanned lunar probes. We conclude that those five sites differ significantly only in minor constituents and/or relative valence states and that those differences are more modest than the differences that characterize mare regions generally. Recommendations of priorities for the five prime Apollo sites are made based on their uniqueness for sample return. Sampling of other lunar localities displaying anomalous emissivities and extreme color differences will be required to ascertain the full range of lithologies that constitute the lunar surface.", "doi": "10.1029/JB074i017p04382", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1969-08-15", "series_number": "17", "volume": "74", "issue": "17", "pages": "4382-4384" }, { "id": "authors:cy0xd-8gr38", "collection": "authors", "collection_id": "cy0xd-8gr38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141107-161158355", "type": "article", "title": "Reconnaissance of infrared emission from the lunar nighttime surface", "author": [ { "family_name": "Wildley", "given_name": "Robert L.", "clpid": "Wildley-R-L" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Westphal", "given_name": "James A.", "clpid": "Westphal-J-A" } ], "abstract": "The reconnaissance described in this paper was performed in 1964 and is an extension and refinement of the first observations (1962), in the 8- to 14-\u03bc wavelength region, of the thermal emission from the lunar nighttime surface [Murray and Wildey, 1964]. The present investigation was intended to sample representatively enough of the lunar surface to determine the general character of the lunar nighttime emission and the relative abundance of nighttime infrared anomalies.\n\nMore complete studies of the infrared emission with higher spatial resolution during eclipse were made at about the same time [Saari and Shorthill, 1965].", "doi": "10.1029/JZ072i014p03743", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1967-07-15", "series_number": "14", "volume": "72", "issue": "14", "pages": "3743-3749" }, { "id": "authors:qqm0v-0pr11", "collection": "authors", "collection_id": "qqm0v-0pr11", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151208-111556213", "type": "article", "title": "Planetary Contamination II: Soviet and U.S. Practices and Policies", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Davies", "given_name": "Merton E.", "clpid": "Davies-M-E" }, { "family_name": "Eckman", "given_name": "Philip K.", "clpid": "Eckman-P-K" } ], "abstract": "The accompanying article of Horowitz et al. concluded with the view that the COSPAR recommendations regarding Mars should be adjusted to reflect new environmental information. Specifically, it was concluded that viable terrestrial microorganisms which are transported to Mars inside solid components in sealed spaces have a low probability of being released to the surface or atmosphere, and that, if any are released, they are not likely to infect the planet. We suggest, in addition, that both the COSPAR recommendations and U.S. planetary quarantine policy should be altered to take into account past and continuing Soviet practice regarding the exploration of Mars and Venus. No amount of analysis by COSPAR, or of costly, self-imposed restrictions by the U.S. on its own planetary exploration program, can reduce the probability of contamination of either Venus or Mars below what the Soviets have already made it, or will make it as they continue their large planetary effort. All that U.S. policy can accomplish is to insure that U.S. efforts do not significantly increase the probability above that level. Any recommended policy which would require the U.S. to apply significantly more stringent restrictions is illogical in that, in effect, the U.S. would be asked to increase greatly the cost and complexity of its planetary program without achieving any significant reduction in the probability of actual contamination. There exists some parallelism between the problem of planetary quarantine and that of radioactive fallout from atmospheric nuclear testing, although the desirable solution to the quarantine problem is not merely to stop all activity. Both are multilateral problems, and individual national policy necessarily must reflect the policy of other nations. Thus, the real questions that must be faced by COSPAR, and by the U.S., are, (i) What is the prob able number of viable terrestrial microorganisms already transported to Venus and to Mars? and (ii) What is the total number to be expected in the next decade or so from foreseeable Soviet efforts alone? Then COSPAR can recommend, and the U.S. can decide, that the total U.S. contribution should be equal to some specified fraction of the total present and future Soviet contribution.\n\nThis approach in turn suggests that every effort should be made to induce the Soviets to supply additional de tails on the Zond 2 and Venus 3 mission and trajectory and, particularly, on the procedure used for sterilizing the components and assembly of both space craft. With such information, the probable number of viable terrestrial microorganisms deposited on Venus and Mars could be estimated well enough to permit a realistic quantitative analysis of what U.S. policy and practice should be. However, if more complete information on Soviet practice cannot be obtained, then, it seems to us, the U.S. has no logical alternative but to permit greater engineering freedom in lander delivery technique and to accept gaseous and other nonthermal sterilization procedures, where necessary, in its own program. By relying on the demonstrated U.S. spacecraft reliability to insure that the U.S. contribution to planetary contamination will remain significantly less than the Soviet contribution, we could reduce significantly the cost and time required to carry out serious scientific investigations of the surfaces of Venus and Mars.", "doi": "10.1126/science.155.3769.1505", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1967-03-24", "series_number": "3769", "volume": "155", "issue": "3769", "pages": "1505-1511" }, { "id": "authors:q9fqb-29a85", "collection": "authors", "collection_id": "q9fqb-29a85", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151214-103216447", "type": "article", "title": "Infrared Evidence of Differential Surface Processes on the Moon", "author": [ { "family_name": "Murray", "given_name": "B. C.", "clpid": "Murray-B-C" } ], "abstract": "The following summarizes certain previously unpublished inferences regarding the lunar surface that were included in a more extensive oral presentation.", "doi": "10.1098/rspa.1967.0029", "issn": "0962-8444", "publisher": "Royal Society", "publication": "Proceedings of the Royal Society of London. Series A, Mathematical, Physical and Engineering Sciences", "publication_date": "1967-02-07", "series_number": "1446", "volume": "296", "issue": "1446", "pages": "347" }, { "id": "authors:mar07-8vz92", "collection": "authors", "collection_id": "mar07-8vz92", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151214-074151225", "type": "article", "title": "Behavior of Carbon Dioxide and Other Volatiles on Mars", "author": [ { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" } ], "abstract": "We have found that a rather simple thermal model of the Martian surface, in combination with current observations of the atmospheric composition, points strongly toward the conclusion that the polar caps of Mars consist almost entirely of frozen CO_2. This study was based upon the following principal assumptions.\n1) Carbon dioxide is a major constituent of the Martian atmosphere.\n2) The blanketing effect of the atmosphere is small, and due principally to the absorption band of CO_2 near 15 microns.\n3) Lateral and convective heat transfer by the atmosphere is negligible.\n4) The far-infrared emissivity of the Martian soil and of solid CO_2 are near unity.\n5) The reflectivities of the soil and of solid CO_2 in the visible part of the spectrum are about 0.15 and 0.65, respectively.\n6) Values for soil conductivity, density, and specific heat are those characteristic of powdered minerals at low gas pressure.\n7) Water is a minor constituent of the Martian atmosphere, the maximum total amount in the atmosphere being 10 to 30 X 10^(-4) g cm^(-2).\nIn addition, several simplifications were made, which might have significant effects but should not alter our principal conclusions. Among these are the following.\n1) Local blanketing or snowfall effects due to clouds or polar haze were ignored.\n2) Dark and light areas were not differentiated in this study, although Sinton and Strong (6) have observed temperature differences between such areas.\n3) The effects of local topography and microrelief were neglected. We believe that these must have quite significant effects at the higher latitudes, especially in connection with the evaporation of the remanent south polar cap.\n4) Variation of reflectivity with angle of incidence of the sunlight was neglected.\n5) Temperature dependence of soil conductivity and specific heat was ignored.\n6) Effects of saturation of the soil by ice upon the thermal properties of the soil were neglected.\nAlthough in our main investigation we used certain specific values for the various relevant parameters, we also tested the effects of moderate changes in these quantities. Specifically, the soil conductivity was varied by a factor of 3, the albedo and emissivity of the surface were changed by 15 to 20 percent, and the effects of a gross amount of atmospheric blanketing were studied, as described. Only the last of these variations had any significant effect on the model, and other results of the atmospheric blanketing were in disagreement with other physical observations of the planet. Consequently, we find it difficult to avoid the conclusion that CO_2 must condense in large amounts relative to H_20.\nThe main conclusions indicated by this study are the following.\n1) The atmosphere and frost caps of Mars represent a single system with CO_2 as the only active phase.\n2) The appearance and disappearance of the polar caps are adequately explained on the presumption that they are composed almost entirely of solid CO_2 with perhaps an occasional thin coating of water ice.\n3) If the currently reported water-vapor observations are correct, water-ice permafrost probably exists under large regions of the planet at polar and temperate latitudes.\n4) The geochemically anomalous enrichment of CO_2 relative to N_2 in the present Martian atmosphere may be a result of selective trapping of CO_2 in the solid phase at and under the surface.\n5) If the basic evaporation and condensation mechanisms for CO_2 and H_2O discussed in this article are correct, the possible migration of volatile organic compounds away from the warm temperate regions of the planet and their possible accumulation in the polar regions need to be carefully considered.", "doi": "10.1126/science.153.3732.136", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1966-07-08", "series_number": "3732", "volume": "153", "issue": "3732", "pages": "136-144" }, { "id": "authors:btg62-3bb94", "collection": "authors", "collection_id": "btg62-3bb94", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151214-073331769", "type": "article", "title": "A Comparison of U.S. and Soviet Efforts to Explore Mars", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Davies", "given_name": "Merton E.", "clpid": "Davies-M-E" } ], "abstract": "The year 1965 was a momentous one in the unmanned exploration of Mars. The U.S. spacecraft Mariner IV\nobtained 21 close-up pictures of that planet and successfully returned these and other scientific data to Earth. Earlier in the year, a larger Soviet spacecraft, Zond II, failed in flight after completing 61 percent of the\njourney-almost an exact repetition of the failure of the earlier Soviet spacecraft Mars I, launched 1 November 1962.", "doi": "10.1126/science.151.3713.945", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1966-02-25", "series_number": "3713", "volume": "151", "issue": "3713", "pages": "945-954" }, { "id": "authors:a634v-z9008", "collection": "authors", "collection_id": "a634v-z9008", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151211-152235288", "type": "article", "title": "Mariner IV Photography of Mars: Initial Results", "author": [ { "family_name": "Leighton", "given_name": "Robert B.", "clpid": "Leighton-R-B" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Sharp", "given_name": "Robert P.", "clpid": "Sharp-R-P" }, { "family_name": "Allen", "given_name": "J. Denton", "clpid": "Allen-J-D" }, { "family_name": "Sloan", "given_name": "Richard K.", "clpid": "Sloan-R-K" } ], "abstract": "The 22 photographs of Mars taken by Mariner IV have been successfully received on earth. The Martian surface photographed is rather densely populated with impact craters whose sizes range up to at least 120 kilometers in diameter. We infer that the visible Martian surface is extremely old and that neither a dense atmosphere nor oceans have been present on the planet since the cratered surface was formed.", "doi": "10.1126/science.149.3684.627", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1965-08-06", "series_number": "3684", "volume": "149", "issue": "3684", "pages": "627-630" }, { "id": "authors:5g3yb-m2y79", "collection": "authors", "collection_id": "5g3yb-m2y79", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141110-104911592", "type": "article", "title": "Thermal infrared emission of the Jovian disk", "author": [ { "family_name": "Wildey", "given_name": "Robert L.", "clpid": "Wildey-R-L" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Westphal", "given_name": "James A.", "clpid": "Westphal-J-A" } ], "abstract": "The 8\u201314 micron infrared emission of Jupiter has been observed on six nights in December 1963 using the 200-inch Hale telescope. The new observations possess twice the resolution of those obtained in 1962. The brightness temperature at the center of the disk appears to be nearly constant at 129\u00b0K. With some slight ambiguity, the light bands are about 0.5\u00b0 cooler in appearance than the dark bands. There is some suggestion of morning-evening asymmetry in one of the bands. The Great Red Spot is found to be from 1.5\u00b0 to 2.0\u00b0 cooler than the surrounding disk at the newer resolution.", "doi": "10.1029/JZ070i015p03711", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1965-08-01", "series_number": "15", "volume": "70", "issue": "15", "pages": "3711-3719" }, { "id": "authors:qf5gq-jcg23", "collection": "authors", "collection_id": "qf5gq-jcg23", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151120-090218795", "type": "article", "title": "The 8-14-\u03bc Appearance of Venus Before the 1964 Conjunction", "author": [ { "family_name": "Westphal", "given_name": "J. A.", "clpid": "Westphal-J-A" }, { "family_name": "Wildey", "given_name": "R. L.", "clpid": "Wildey-R-L" }, { "family_name": "Murray", "given_name": "B. C.", "clpid": "Murray-B-C" } ], "abstract": "In an earlier paper (Murray, Wildey, and Westphal 1963) we have described the detailed\nmapping of the 8-14-\u03bc radiation from Venus using the 200-inch Hale telescope.\nThis paper extends that work over a period of about 7 months from December 15, 1963,\nto June 6, 1964. Detailed maps for 6 days are presented that show the morphology of\nthe upper-atmosphere brightness temperature and illustrate a number of anomalous\nfeatures near the cusps. The problem of atmospheric extinction and the derived brightness\ntemperature is discussed.", "doi": "10.1086/148347", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "1965-08", "volume": "142", "pages": "799-801" }, { "id": "authors:61ytq-jjc60", "collection": "authors", "collection_id": "61ytq-jjc60", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20120921-094247658", "type": "article", "title": "Surface Temperature Variations during the Lunar Nighttime", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Wildey", "given_name": "Robert L.", "clpid": "Wildey-R-L" } ], "abstract": "A new photometer incorporating a mercury-doped germanium photoconductor has been used with a 19-inch telescope to measure the 8-14- brightness temperatures of the shaded lunar surface. Right- ascension scans carried into the lunar nighttime from the terminator show a characteristic of cooling inconsistent with the occurrence of a thick homogeneous dust layer. It appears th more highiy conducting material either is exposed commonly on the surface or constitutes a substratum generally covered by no more than a centimeter or so of the strongly insulating dust. No difference in nighttime temperature distribution was observed between maria and uplands. However, local areas of higher-thanaverage brightness temperature were encountered. These indicate extensive exposures of consolidated material. Local temperature anomalies of this type are associated with the bright-rayed craters Tycho and Copernicus, but they are distributed over an area larger than that represented by the respective craters. Two other groups of temperature anomalies were found in otherwise undistinguished mare border areas. These observations and others suggest that surface redistribution processes are operative on the lunar surface over at least a 10-meter range, but are not important over distances much in excess of a kilometer.", "doi": "10.1086/147799", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "1964-02", "series_number": "2", "volume": "139", "issue": "2", "pages": "734-750" }, { "id": "authors:bt60z-0gd59", "collection": "authors", "collection_id": "bt60z-0gd59", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141107-142925330", "type": "article", "title": "Infrared photometric mapping of Venus through the 8- to 14-micron atmospheric window", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Wildey", "given_name": "Robert L.", "clpid": "Wildey-R-L" }, { "family_name": "Westphal", "given_name": "James A.", "clpid": "Westphal-J-A" } ], "abstract": "The 200-inch Hale telescope has been used to obtain high-resolution maps, on four mornings juxtaposed about the Mariner 2 encounter, of the brightness temperature of Venus in the 8- to 14-micron wavelength interval. The resolution was about 1/30 of the disk of Venus. The signal-to-noise ratio was in excess of 100. The maps reveal (1) a general limb darkening, (2) a bilateral symmetry about the planet's orbital plane, (3) a very slight wedging of the contours as the only day-to-night effect, and (4) a transient temperature anomaly in the southern hemisphere.", "doi": "10.1029/JZ068i016p04813", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1963-08-15", "series_number": "16", "volume": "68", "issue": "16", "pages": "4813-4818" }, { "id": "authors:pajcd-qqt42", "collection": "authors", "collection_id": "pajcd-qqt42", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:WESao63", "type": "article", "title": "An 8-14 micron infrared astronomical photometer", "author": [ { "family_name": "Westphal", "given_name": "James A.", "clpid": "Westphal-J-A" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Martz", "given_name": "Dowell E.", "clpid": "Martz-D-E" } ], "abstract": "A system for measurement of 8-14 \u00b5 infrared emission from extra-terrestrial objects is described. The photometric system utilizes a mercury-doped germanium detector cooled to liquid hydrogen temperature to achieve increased sensitivity in this spectral region. A method is presented for minimizing the problem of atmospheric and component emission. The system has been used to measure the radiation from the star \u03b1 Orionis, from the unilluminated moon, and from several planets.", "issn": "0003-6935", "publisher": "Optical Society of America", "publication": "Applied Optics", "publication_date": "1963-07", "series_number": "7", "volume": "2", "issue": "7", "pages": "749-753" }, { "id": "authors:q50da-98q22", "collection": "authors", "collection_id": "q50da-98q22", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20151211-083052794", "type": "article", "title": "Venus: A Map of Its Brightness Temperature", "author": [ { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Wildey", "given_name": "Robert L.", "clpid": "Wildey-R-L" }, { "family_name": "Westphal", "given_name": "James A.", "clpid": "Westphal-J-A" } ], "abstract": "The 200-inch Hale telescope has been used to make high-resolution maps of the brightness temperature of Venus at wavelengths 8 to 14 microns. Resolution of about 1/30 of the disk reveals a general symmetry about the plane of the orbit, no daynight temperature effects, and a transient temperature anomaly in the southern hemisphere.", "doi": "10.1126/science.140.3565.391", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "1963-04-06", "series_number": "3565", "volume": "140", "issue": "3565", "pages": "391-392" }, { "id": "authors:4zdas-np364", "collection": "authors", "collection_id": "4zdas-np364", "cite_using_url": "https://authors.library.caltech.edu/records/4zdas-np364", "type": "article", "title": "New Applications of Lunar Shadow Studies", "author": [ { "family_name": "Pohn", "given_name": "H.", "clpid": "Pohn-Howard" }, { "family_name": "Murray", "given_name": "B. C.", "clpid": "Murray-B-C" }, { "family_name": "Brown", "given_name": "H.", "clpid": "Brown-Harrison" } ], "abstract": "

The use of shadows as a means of investigating lunar topography is nearly as old as the telescope itself. A number of investigators computed heights of features, the best being Beer and Mädler and Schmidt. Unfortunately a number of systematic errors in the investigations of these early workers were overlooked by later observers and remained to compound and confuse the problem. Most recently the work of Kopal and his associates at the University of Manchester has served to clarify the problem
as well as to establish quite sensitive photographic and microdensitometric techniques for studying shadow progression.

", "doi": "10.1086/127767", "issn": "0004-6280", "publisher": "IOP Publishing", "publication": "Publications of the Astronomical Society of the Pacific", "publication_date": "1962-04", "series_number": "437", "volume": "74", "issue": "437", "pages": "93-105" }, { "id": "authors:x4pdh-e3f38", "collection": "authors", "collection_id": "x4pdh-e3f38", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141110-114827859", "type": "article", "title": "The behavior of volatiles on the lunar surface", "author": [ { "family_name": "Watson", "given_name": "Kenneth", "clpid": "Watson-K-M" }, { "family_name": "Murray", "given_name": "Bruce C.", "clpid": "Murray-B-C" }, { "family_name": "Brown", "given_name": "Harrison", "clpid": "Brown-Harrison" } ], "abstract": "Volatiles, and water in particular, have been thought to be unstable on the lunar surface because of the rapid removal of constituents of the lunar atmosphere by solar radiation, solar wind, and gravitational escape. The limiting factor in removal of a volatile from the moon, however, is actually the evaporation rate of the solid phase, which will be collected at the coldest points on the lunar surface. We present a detailed theory of the behavior of volatiles on the lunar surface based on solid-vapor kinetic relationships, and show that water is far more stable there than the noble gases or other possible constituents of the lunar atmosphere. Numerical calculations indicate the amount of water lost from the moon since the present surface conditions were initiated is only a few grams per square centimeter of the lunar surface. The amount of ice eventually detected in lunar 'cold traps' thus will provide a sensitive indication of the degree of chemical differentiation of the moon.", "doi": "10.1029/JZ066i009p03033", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1961-09", "series_number": "9", "volume": "66", "issue": "9", "pages": "3033-3045" }, { "id": "authors:kf8fw-r0813", "collection": "authors", "collection_id": "kf8fw-r0813", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141110-121847098", "type": "article", "title": "On the possible presence of ice on the Moon", "author": [ { "family_name": "Watson", "given_name": "Kenneth", "clpid": "Watson-K-M" }, { "family_name": "Murray", "given_name": "Bruce", "clpid": "Murray-B-C" }, { "family_name": "Brown", "given_name": "Harrison", "clpid": "Brown-Harrison" } ], "abstract": "It is generally presumed that gases of low molecular weight escape very rapidly from the moon. As a consequence, it has been assumed that volatile substances, such as water, which possess short relaxation times for escape, do not exist there. Urey [1952] recognized that there may be depressions in which the sun never shines, and in which some condensed volatile substances could be present, but he concluded that no solid or liquid water could exist on the moon for more than very short periods of time. Kuiper [1952], following a suggestion by Herzberg, stated that SO_2 molecules might be concentrated on the night side of the moon.", "doi": "10.1029/JZ066i005p01598", "issn": "0148-0227", "publisher": "American Geophysical Union", "publication": "Journal of Geophysical Research", "publication_date": "1961-05", "series_number": "5", "volume": "66", "issue": "5", "pages": "1598-1600" } ]