Extrraterrestial Ice articles

       Barlow N. G.
       The search for possible source craters for martian meteorite ALH 84001. 
       ALH 84001 was ejected from Mars ~16 million years ago by an asteroid impact.
       The impact crater source of ALH 84001 is not known; two young craters in
       ancient highlands, eroded by water, are suggested as the most likely candidates.

       Rice J. W. Jr.
       Searching for the ALH 84001 “smoking gun” (parent crater). 
       The author lists the 19 youngest craters on ancient (Noachian) areas of Mars;
       among these, he suggests that the source crater of ALH 84001 is probably in
       Memnonia at 5°S, 146°W.

PHYSICS NEWS UPDATE                         
The American Institute of Physics Bulletin of Physics News
Number 262  March 14, 1996    by Phillip F. Schewe and Ben

time.  The Hubble Space Telescope has snapped a series of high-
resolution pictures throughout Pluto's 6.4-day rotation period.  The
photo sequence reveals that Pluto possesses more visible large-scale
features than any  planet except for Earth.  The features include a
variety of dark and bright spots and a dark stripe across the frosty
north pole.  Pluto had not previously been imaged clearly before,
even with the bigger Earth-based telescopes, because its angular
size on the sky is only a tenth of an arcsecond across. All of this
comes at a time when some astronomers want to take away Pluto's
status as a planet. (NASA press release, 7 March 1996.)

A NEW FORM OF ICE has been predicted to form at high pressures. Ice has more solid forms than any other simple substance, with 10 known crystalline structures. Using molecular dynamics simulations, a German-French-Italian team has now predicted that "Ice XI" forms between 3 and 4 Megabars of pressure at room temperature. The oxygen atoms arrange themselves into a distorted hexagonal close-packed (hcp) lattice, a densely-packed structure in which atoms essentially occupy the corners of equilateral triangles. Interestingly, Ice XI is an insulator up to and beyond 7 Mbars, the kinds of pressures at which ice exists in Jupiter. Numerous physicists have proposed that ice may become metallic at high pressures, but the simulations suggest that Jovian ice may not necessarily be metallic. The pressures that would be required to make Ice XI can be experimentally achieved in diamond anvil cells, the authors point out. (M. Benoit et al, upcoming paper in Phys. Rev. Lett.)
http://www.rcch.com/canada/athena/links.htm http://www.physics.sfsu.edu/~gmarcy/planetsearch/planetsearch.html
Title: Energy analysis of porous water ice under space-simulated conditions: results from the KOSI-8 experiment Authors: BENKHOFF, J.; SEIDENSTICKER, K. J.; SEIFERLIN, K.; SPOHN, T. Journal: Planetary and Space Science v. 43, p. 353-361 Publication Date: 03/1995 Origin: ELSEVIER Bibliographic Code: 1995P&SS...43..353B
Title: Statistical Studies of ISEE 3/ICE Observations of Impulsive Hard X-Ray Solar Flares Authors: BROMUND, KENNETH R.; MCTIERNAN, JAMES M.; KANE, SHARAD R. Journal: Astrophysical Journal v.455, p.733 Publication Date: 12/1995 Origin: APJ ApJ Keywords: SPACE VEHICLES, SUN: FLARES, SUN: X-RAYS, GAMMA RAYS B
Title: Ice/dust mixtures in simulated space environment: A study of sublimation and of related phenomena Authors: LAEMMERZAHL, P. Affiliation: AAMax-Planck-Inst. fuer Kernphysik, Heidelberg, Germany Journal: Advances in Space Research (ISSN 0273-1177), vol. 15, no. 10, p. 19-28 Publication Date: 00/1995 Category: Lunar and Planetary Exploration Origin: STI NASA/STI Keywords: CARBON DIOXIDE, DUST, ICE, SPACE ENVIRONMENT SIMULATION, SUBLIMATION, WATER, CHEMICAL ANALYSIS, COMET NUCLEI, COMETS, MASS SPECTROSCOPY, TEMPERATURE EFFECTS Bibliographic Code: 1995AdSpR..15...19L Abstract In the KOmetenSImulation (KOSI) project decimeter-sized porous ice/dust mixtures were investigated in a simulated space environment. A variety of experimental techniques was applied for simultaneous in situ measurements of parameters of the interior, the surface, and emissions of the inosolated samples. Sublimation rates declined in all cases when the dust/ice ratio was approximately 0.1 or more, indicating formation of a dust mantle. At a lower dust/ice ratio of 0.02 sublimation rate was constant indicating erosion of the dust from the surface. Investigations on mixtures of H2O and CO2 ices coordinating results from mass spectrometric, chemical and temperature analyses showed that inbound flow of sublimated CO2 is significant (approximately 50 percent). Inbound flow of H2O vapor was studied by isotopic tracing; the results stress the importance of texture changes by grain sintering for the enhancement of thermoconductivity. The process of dust mantle formation was observed, by IR mapping of surface temperatures, to be inhomogeneous with local fluctuations of growth and erosion alternating. From measured dynamic parameters of ejected particles, conclusions on the importance of cohesive forces in relation to gravity and gas drag could be drawn.
Title: On the origin of surface morphologies of Saturn's icy moons Authors: NEAGU, A. Affiliation: AAIPEE Curtea de Arges, Romania Journal: Meteoritics (ISSN 0026-1114), vol. 29, no. 4, p. 510 Publication Date: 07/1994 Category: Lunar and Planetary Exploration Origin: STI NASA/STI Keywords: GEOMORPHOLOGY, ICY SATELLITES, METEORITE CRATERS, SATELLITE SURFACES, SATURN SATELLITES, ASTRONOMICAL MODELS, GRAVITATIONAL EFFECTS, HYPERVELOCITY IMPACT, VOYAGER PROJECT Bibliographic Code: 1994Metic..29Q.510N Abstract Voyager images of Saturn's icy moons revealed that, apparentaly, most of these planetary bodies evolved substanially since the time they accreted, although models of thermal evolution of small icy satellites indicate that such bodies would experience little internal activity after formation. Several of the saturnian satellites (Rhea, Dione, Tethys, Mimas) were imaged at high resolution that allowed identification of terrain types of distinctly different morphology ranging from rough, heavily cratered areas to smooth, lightly cratered plains. At the same time the size-frequency distribution of impact craters for various regions of the saturnian moons'surfaces indicate that the satellites are dominated by two populations of craters. Some models have been developed to explain the putative prolonged postaccretional geologic activity that reworked large parts of the saturnian moons' surfaces. But no one predicts surface or near-surface melting. Presented is a model of saturnian satellites evolution that explains the appearance of their resurfaced areas without taking into account any important geologic activity of their interior. According to this model, immediately after their accretion the saturnian moons were intensely bombarded by objects left over from saturnian system formation. At about 3.9 Ga the Sun underwent a very violent explosive phase, expelling into space some percentage of its mass and generating the second great thermal event (SGTE) in the history of the solar system. The result was the change of the moons' spin into a synchronous rotation and the disappearance or subduction of population I craters on large parts of the moons' surfaces. The model is strongly supported by the available data on the saturnian satellites and by abundant evidence in favor of the SGTE occurrence at 3.9 Ga. At the same time, this model is in agreement with the assumption of McKay et al. concerning the origin of molecular N and organics on primordial Titan.
Title: Charon: More than water ice? Authors: ROUSH, TED L. Affiliation: AASan Francisco State Univ., San Francisco, CA, US Journal: ICARUS, vol. 108, no. 2, pt. 1, p. 243-254 Publication Date: 04/1994 Category: Astronomy Origin: STI NASA/STI Keywords: ASTRONOMICAL MODELS, ASTRONOMICAL SPECTROSCOPY, CARBON DIOXIDE, CHARON, ICE, LIQUID-GAS MIXTURES, METHANE, PLANETARY COMPOSITION, SOLIDIFIED GASES, SPECTROSCOPIC ANALYSIS, GRAIN SIZE, MATHEMATICAL MODELS, PLANETARY EVOLUTION, PLUTO (PLANET) Bibliographic Code: 1994Icar..108..243R Abstract A significant non-H2O ice component may be present on the surface of Pluto's satellite Charon and yet remain undetected by existing observations. This suggestion arises from a comparison of calculated reflectance spectra with Charon's 1.5- to 2.5-micron reflectance spectrum. The calculated spectra rely upon descriptions of the interaction of light scattered from particulate surfaces and the optical constants of H2O, CH4, and CO2 ices. Calculated spectra of mixtures composed of H2O and CO2 ice remain consistent with the observed spectrum of Charon for high abundances of CO2 (approximately 50% relative mass fraction) in intimate mixtures, and for areal coverages of about 40% CO2 in spatial mixtures. Calculations for mixtures of H2O and CH4 ice indicate that greater than or = 5% relative mass fraction of CH4 in intimate mixtures and greater than or = 5-10% areal coverage of CH4 in spatial mixtures result in spectra that cannot reproduce the observed Charon spectrum. Calculated spectra of three-component intimate mixtures of H2O, CH4, and CO2 ices with similar grain sizes can fit the observed spectrum of Charon only for low abundances of CH4 (less than or = 5%). If the CH4 ice grain size is much greater than the other components, then the spectrum of Charon can be modeled by calculated spectra containing up to approximately 30% CH4 in the intimate mixtures. Calculated spectra for spatial mixtures of H2O, CH4, and CO2 ices indicate that less than or = 5-10% areal coverage of CH4 can be incorporated and remain consistent with the observational data. The suggestion of significant amounts of non-H2O components on Charon can be tested as Earth-based telescopic instrumentation improves. This suggestion should be considered during instrumental design for spacecraft destined for the Pluto-Charon system.
Title: The electrolytical processes in dirty ices: Implications for origin and chemistry of minor bodies and related objects Authors: DROBYSHEVSKI, E. M.; CHESNAKOV, V. A.; SINITSYN, V. V. Affiliation: AARussian Academy of Sciences, St. Petersburg, Russia ABRussian Academy of Sciences, Chernogolovka, Russia ACRussian Academy of Sciences, Chernogolovka, Russia Journal: Advances in Space Research (ISSN 0273-1177), vol. 16, no. 2, p. (2)73-2(84) Publication Date: 07/1994 Category: Astrophysics Origin: STI NASA/STI Keywords: ASTEROIDS, CHEMICAL EXPLOSIONS, COMET NUCLEI, ELECTROLYSIS, ICE, PROTOPLANETS, CONVECTION, ELECTRIC CURRENT, GAS GIANT PLANETS, HALLEY'S COMET, ORGANIC SOLIDS, PLANETARY MAGNETOSPHERES, SPACE PLASMAS Bibliographic Code: 1994AdSpR..16...73D Abstract Many moonlike bodies (M approximately equal to 1 Moon) beyond the Martian orbit contain large amounts of dirty ice (approximately 50%) forming a thick mantle with the solid phase thermal convection. When a body moves through the inter- or nearplanetray magnetized plasma, electric current is generated in the body and its environment. The current passing through a dirty ice containing up to 10% organic admixtures produces a lot of electrochemical effects which have a profound impact on its composition. At this stage one can hardly say something definite concerning changes experienced by organics. The changes must occur inevitably and can be of a rather unexpected and far-reaching nature, thus deserving close study. Another obvious effect is a volumetric electrolysis of ice containing alien inclusions. The electrolysis products accumulate in ice in the form of a solid solution which is capable of detonation at 15-20 wt.% of 2H2 + O2. If M is greater that or approximately equal to 1 Moon (Galilean satellites, Titan), the body loses in explosion a part of its mass in the form of vapor and ice fragments (i.e. short-period (SP) comet nuclei), whereas if M is less than or approximately equal to 0.2 Moon, the body breaks up totally (the Main Belt (MB) asteroids origin approximately 3.9 Byr ago). 2H2 + O2 containing cometary nuclei are capable of burning or suffering new explosions when receiving additional energy. The combustion in the sublimation products containing light organics and 2H2 + O2 explains unexpected energetics and nearnuclear chemistry of Comet P/Halley (e.g. great abundances of negative and positive ions, atomic carbon, Co over CO2, origin of CHON particles, etc) and its distant outbursts correlated, possibly with Solar activity. Thus the electrochemical processes in the dirty ice with organics, along with its subsequent thermal, radiative etc. processing, open up new potentials for explanation and prediction of quite unexpected discoveries.
Title: The formation of organic molecules in astronomical ices Authors: SCHUTTE, W. A. Affiliation: AALeiden Observatory Laboratory, Leiden, The Netherlands Journal: Advances in Space Research (ISSN 0273-1177), vol. 16, no. 2, p. (2)53-(2)60 Publication Date: 07/1994 Category: Astrophysics Origin: STI NASA/STI Keywords: ICE ENVIRONMENTS, INTERSTELLAR CHEMISTRY, INTERSTELLAR MATTER, ORGANIC SOLIDS, ASTRONOMICAL MODELS, COMETS, FORMALDEHYDE, INFRARED SPACE OBSERVATORY (ISO), NITROGEN, OXYGEN, ULTRAVIOLET ASTRONOMY Bibliographic Code: 1994AdSpR..16...53S Abstract An absorption feature at 3.4 micrometers has been observed in various lines-of-sight through the diffuse interstellar medium. Its position and width lead to an identification with the C-H stretching mode of solid organic material. A possible mechanism for the production of organic solids in the interstellar medium is UV photoprocesisng of icy mantles which accrete on dust grains in dense clouds. Furthermore, thermally induced reactions involving formaldehyde molecules in the mantles could be an important source of organics. Laboratory simulation of these processes shows that a large variety of oxygen- and nitrogen-rich species may be produced. It is shown that the occurrence of periodic transient heating events plays an important role in the production of organic material in the ice mantles. Finally, it is pointed out how future missions like the Infrared Space Observatory (ISO) as well as analysis of comet material by Rosetta may be able to clarify the nature and evolution of interstellar organics.
Title: Mercury - Full-disk radar images and the detection and stability of ice at the North Pole Authors: BUTLER, BRYAN J.; MUHLEMAN, DUANE O.; SLADE, MARTIN A. Affiliation: AB(California Inst. of Technology, Pasadena) AC(JPL, Pasadena, CA) Journal: Journal of Geophysical Research (ISSN 0148-0227), vol. 98, no. E8, p. 15,003-15,023. Publication Date: 08/1993 Category: Lunar and Planetary Exploration Origin: STI NASA/STI Keywords: ICE, MERCURY SURFACE, POLAR REGIONS, RADAR IMAGERY, VERY LARGE ARRAY (VLA), DEEP SPACE, RADAR ANTENNAS, SUPERHIGH FREQUENCIES Bibliographic Code: 1993JGR....9815003B Abstract The first full-disk radar images of Mercury are discussed. About 77 percent of the surface was imaged at resolutions as good as 150 km. The North Pole was visible at the time of the observations, and the feature with the highest same sense (SS) circular reflectivity in the images is near the nominal polar position. The peak SS reflectivity of this feature is 7.9 percent and the circular polarization ratio through much of it is over one. The diameter of the feature is estimated to be less than about 350 km. The signal strength and polarization characteristics suggest the presence of very clean ices deposited in a relatively short period. The reflectivity of the north polar feature is slightly depressed compared to absolute reflectivities of other ice bodies and regions in the solar system. This may be due to a layer of dust or soil covering the ice. Other prominent features in the unphotographed hemisphere correpond to positions where atmospheric sodium enhancements have been measured from earth. These sites may be large basins similar to the Caloris basin.
Title: Time, ice and terraforming Authors: SMITH, ALEXANDER G. Journal: British Interplanetary Society, Journal (ISSN 0007-094X), vol. 46, no. 8, p. 305-310. Publication Date: 08/1993 Category: Space Sciences (General) Origin: STI NASA/STI Keywords: ECONOMIC FACTORS, ENVIRONMENTAL ENGINEERING, PLANETARY ENVIRONMENTS, SPACE EXPLORATION, TECHNOLOGY ASSESSMENT, ENVIRONMENT EFFECTS, ICE ENVIRONMENTS, INTERSTELLAR TRAVEL Bibliographic Code: 1993JBIS...46..305S Abstract It is argued that terraforming of a variety of extra-solar planets may provide humanity with the expertise needed to avert the next glacial period, if economic competition and its requirement of profitability allow a step-by-step development through the advances required for space-based civilization, interstellar flight, and semiautonomous robotic manufacturing. Technological, economic, and biological constraints on engineering progress are discussed. A scenario for interstellar travel and terraforming is presented.
Title: Outer planets and icy satellites Authors: DROBYSHEVSKI, E. M. Affiliation: Academy of Sciences (USSR), Leningrad. Journal: In Arizona Univ., Resources of Near-Earth Space: Abstracts p 37 (SEE N91-26019 17-91) Publication Date: 00/1991 Category: Astrophysics Origin: STI NASA/STI Keywords: ASTEROID BELTS, ASTEROIDS, CALLISTO, EUROPA, GANYMEDE, GAS GIANT PLANETS, ICE, ICY SATELLITES, IO, METEORITE COLLISIONS, MOON, ORGANIC MATERIALS, PLANETARY MAGNETOSPHERES, SATURN RINGS, TITAN, CHRONOLOGY, EXPLOSIONS, FRAGMENTS, HYPERVELOCITY IMPACT, INCLUSIONS, RESERVOIRS, TIME MEASUREMENT, WATER Bibliographic Code: 1991rnes.nasa...37D Abstract The resources offered by the outer bodies in the Solar System, starting with the main belt asteroids and Jovian System, are not only larger and more diverse but may even be easier to reach than, say, those of Mars. The use of their material, including water and organic matter, depends exclusively on the general strategy of exploration of the Solar System. Of major interest in this respect are the large ice satellites - Titan, Ganymede, and Callisto. Motion through the planetary magnetospheres excites in their ice envelopes megampere currents which, in the presence of rocky, etc., inclusions with electronic conduction should lead to the bulk electrolysis of ice and accumulation in it of 2H2 + O2 in the form of a solid solution. With the concentration of 2H2 + O2 reaching about 15 wt. percent, the solution becomes capable of detonation by a strong meteoritic impact. An explosion of Ganymede's ice envelope about 0.5 By ago could account for the formation of the Trojans and irregular satellites, all known differences between Ganymede and Callisto, and many other things. The explosion of a small icy planet with M approx less than 0.5 Moon created the asteroid belt. Two to three explosions occurred on Io, and two on Europa. The specific features of the longperiod comets close to Saturn's orbit permit dating Titan's envelope explosion as 10,000 yr ago, which produced its thick atmosphere, young Saturn's rings, as well as a reservoir of ice fragments saturated by 2H2 + O2, i.e., cometary nuclei between the orbits of Jupiter and Saturn. Thus these nuclei should contain, besides organic matter, also 2H2 + O2, which could be used for their transportation as well as for fuel for spaceships. Ices of such composition can reside deep inside Deimos, the Trojans, C-asteroids, etc. The danger of a future explosion of Callisto's electrolyzed ices, which would result in a catastrophic bombardment of the Earth by comets, may be high enough to warrant a revision of the priorities and strategy of space exploration.
Title: Gas release from ice/dust mixtures Authors: HESSELBARTH, P.; KRANKOWSKY, D.; LAEMMERZAHL, P.; WINKLER, A.; MAUERSBERGER, K. Affiliation: AD(Max-Planck-Institut fuer Kernphysik, Heidelberg, Federal Republic of Germany) AE(Minnesota, University, Minneapolis) Journal: Geophysical Research Letters (ISSN 0094-8276), vol. 18, Feb. 1991, p. 269-272. Research supported by DFG. Publication Date: 02/1991 Category: Astrophysics Origin: STI NASA/STI Keywords: CHEMICAL COMPOSITION, COMETS, ICE, INTERPLANETARY DUST, SUBLIMATION, CARBON DIOXIDE, COMA, SPACE ENVIRONMENT SIMULATION, WATER Bibliographic Code: 1991GeoRL..18..269H Abstract Measurements of gas fluxes from insolated ice/dust mixtures were performed using pressure gauges and a mass spectrometer placed one meter in front of the sample. The measurements were carried out in the framework of the KOSI program. As soon as the insolation of about one solar constant was started, a fast rise in H2O and CO2 emissions from the fresh surface was detected, followed by a slow decrease of the gas fluxes. When intermittent dark periods occurred, water emission dropped rapidly while CO2 fluxes were measured for hours. Results from labeled isotope layers gave data on sublimation depth and temperature and indicated that sublimated CO2 migrated also toward deeper parts of the sample where it recondensed, producing an enrichment. A simple model is proposed which describes the redistribution of CO2 within the sample consistent with the gas phase and solid phase measurements of CO2 abundances. The present study is of interest in connection with Whipple's theory that comets are composed of ice and dust.
Title: An indirect search for lunar polar ices Authors: GRAHAM, FRANCIS G. Affiliation: AA(Kent State University, East Liverpool, OH) Journal: Space Power - Resources, Manufacturing and Development (ISSN 0883-6272), vol. 9, no. 2-3, 1990, p. 195-204. Research supported by the Space Studies Institute, University of Pittsburgh, Case Western Reserve University, et al. Publication Date: 00/1990 Category: Lunar and Planetary Exploration Origin: STI NASA/STI Keywords: COMET NUCLEI, ICE, LUNAR CRATERS, LUNAR BASES, LUNAR SURFACE, METAL VAPORS Bibliographic Code: 1990SPRMD...9..195G Abstract The possibility of comet-derived ices in permanently shadowed lunar polar craters has been a question for space development for years. Calculations have shown that loss mechanisms exceed present flux; larger primordial cometary input would also now be gone. However, Nemesis theory bombardment scenarios, which are postulated to have caused mass extinctions on earth, would also have caused episodic cometary impacts on the moon, as recently as 13 million years ago, probably sufficient for the maintenance of lunar polar ices by the Arnold mechanism. Less volatile cometary compounds, such as sodium compounds, might have also survived in partially shadowed lunar polar areas where the sun is always low and partially hidden by terrain. Observational experiments were conducted to detect any enhanced sodium vapor emission at the lunar poles. These results were negative at the expected levels. If cometary materials less volatile than ices are not detected at the partially shadowed lunar areas, then doubt exists for the ices' existence in the permanently shadowed craters.
Title: Ice grains in the dust disk of the bipolar nebula M 1-92 Authors: EIROA, C.; HODAPP, K. -W. Affiliation: AB(Hawaii Univ., Honolulu.) Journal: In ESA, Infrared Spectroscopy in Astronomy p 351-353 (SEE N90-19084 11-89) Publication Date: 09/1989 Category: Astrophysics Origin: STI NASA/STI Keywords: ACCRETION DISKS, ICE, INFRARED ASTRONOMY, INFRARED SPECTRA, INTERPLANETARY DUST, NEBULAE, INFRARED TELESCOPES, NASA SPACE PROGRAMS, SPECTRUM ANALYSIS, TWO BODY PROBLEM Bibliographic Code: 1989irsa.rept..351E Abstract The 2.4 to 3.8 microns spectra of the bipolar nebula M 1-92 is investigated. The data is obtained with the cooled grating array spectrometer at the NASA infrared telescope facility. Data is obtained at five positions of the object: one coinciding with the illuminating star, and the rest distributed along the dust torus of the bipolar nebula. No spectral signature is observed at the position of the star. A narrow 3.1 microns absorption is observed in all four positions of the torus. The feature is interpreted as being due to a mixture of pure amorphous and crystalline water ices.

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