DOCSLIB.ORG

Deep Space 2023: the Art of the Possible

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Deep Space 2023: the Art of the Possible COVERmay-fin_Layout 1 4/18/13 12:34 PM Page 1 May 2013 Acquisition reform: Real solutions Shifting fortunes for commercial X-band A conversation with Eddy Pieniazek A P U B L I C A T I O N O F T H E A M E R I C A N I N S T I T U T E O F A E R O N A U T I C S A N D A S T R O N A U T I C S VIEW2layout0513_Layout 1 4/15/13 2:56 PM Page 2 Deep space 2023: The art of the possible “The object of your mission is to ex- tional Research Council report issued shifts in the agency’s overall goals. A plore the Missouri River, and such in December, stated that the agency’s change in NASA fortunes requires a princi pal streams of it, as, by its course progress toward achieving its long- change in strategic direction. and communication with the waters of term priorities is hampered by a lack the Pacific Ocean...may offer the most of national consensus on its strategic How far in a decade? direct and practicable water-commu- goals and objectives. Another serious On the current course, by 2023 NASA nication across the continent, for the obstacle is the mismatch between its astronauts will still be working aboard purposes of commerce.” directed goals and the congressionally the ISS, an outpost heading into its —Thomas Jefferson to Meriwether allocated budget. Because current law twilight years. Commercial transport Lewis, 1803. restricts NASA from reorganizing its firms will be handling resupply, and personnel and infrastructure more ef- NASA will be leasing private space- PRESIDENT JEFFERSON’S ORDER TO ficiently, the agency cannot use its craft for the launch and return of its Meriwether Lewis inaugurating the limited resources more wisely in pur- space station crews. ISS lifeboat serv- Lewis and Clark expedition offers the suit of long-term goals. The panel sug- ices also will have gone commercial, nation a model for guiding its explo- gested that the White House take the shifting that duty to the U.S. for the rations of Earth-Moon space. The U.S. lead in developing a national consen- first time since Russia’s Soyuz assumed should make deep space not only an sus on space polic y goals and provide the role in 2000. NASA will announce arena of scientific exploration, but also a budget better suited to the directives a stream of interesting scientific dis- a fertile economic frontier where pri- it gives NASA. coveries from the ISS, but no scientific vate enterprise and industry can Far from boosting NASA’s re- or technological breakthroughs will thrive. The guiding mission for the U.S sources, the Congress passed a budget have reached the marketplace. In pub- and NASA in the coming decade in March cutting about a billion dollars lic perception, the ISS and its mission should be to explore Earth-Moon through the rest of this fiscal year. will still have a very low profile. space and tap the resources found Whatever the funding details for 2013 By 2023, NASA’s Orion will have there—for the purposes of commerce. and 2014, neither the White House launched just three times, and only “NASA’s Strategic Direction,” a Na- nor the Congress will make any major once with crew aboard. The heavy-lift Space Launch System (SLS) might have two missions under its belt, per- haps propelling the first Orion crew around the Moon in 2021. But these milestones assume flawless perform- ance for Orion and SLS in their initial shakedowns. Budget projections for the 2020s envision NASA flying the SLS/Orion only once every couple of years. With progress and momentum so slow, and without the ability to equal even Apollo achievements, a fu- ture president and Congress could easily decide to end NASA’s entire hu- man space exploration enterprise. NASA hopes its announced deep space goal, an expedition beyond the Moon to a near-Earth asteroid (NEA) by 2025, will finally revive its fortunes. However, progress toward that goal has been elusive: Orion and SLS are hardly on a fast track, and the The SpaceX Dragon was captured and berthed at the ISS by Expedition 34 using Canadarm II on March 3. agency’s ideal targets for such expedi- Future commercial vehicles will be essential in supplying propellant and hardware to exploration outposts in Earth-Moon space. tions have yet to be discovered. 16 AEROSPACE AMERICA/MAY 2013 VIEW2layout0513_Layout 1 4/15/13 2:56 PM Page 3 NASA has not even allotted funds to conduct the half-billion-dollar sur- vey mission, critical to finding a target for the administration’s 2025 asteroid goal. As NASA’s own Small Bodies As- sessment Group reported in January, “Funding a NEO survey mission has the collateral benefits of identifying potential NEO targets for ISRU [in-situ resource utilization] and robotic sci- ence missions, as well as Potentially Hazardous Objects for planetary de- fense.” Yet no funds to commence the needed space-based search (0.3% of the NASA budget over 10 years) can be found. Neither the scientific discoveries to be made in deep space nor the pros- pect of losing leadership to China in that arena seem to energize U.S. poli- cymakers. If science and foreign pol- icy are insufficient prods, perhaps we A deep-space mission to a near-Earth asteroid may reignite NASA’s fortunes. should turn to another incentive, one that has sustained U.S. progress for more than two centuries: entrepre- ric tons. The NEA population harbors ral sources of water, metals, and neurial commercial development. more than half a million objects as volatile organic compounds. They large as or larger than DA14, many on plan to find asteroidal w ater first and Reviving a mission orbits accessible to NASA and private sell it to space agencies, later using Fortunately for NASA and the nation, spacecraft. To date, we have discov- NEA metals, organic compounds, and the agency is already empowered to ered just 10,000, barely 1% of the total rare elements as feedstock for con- help open up the deep space eco- population. struction and industrial processes. The nomic frontier. Congress, in the Na- Two asteroid mining companies, initial benefit derived from the aster- tional Aeronautics and Space Act (as Planetary Resources and Deep Space oids (as from the Moon) is water for amended in 2010), declares: “…the Industries, have already announced use as propellant, to replace hydrogen general welfare of the United States re- their intentions to go after these natu- and oxygen launched at greater cost quires that the Administration seek and encourage, to the maximum ex- tent possible, the fullest commercial use The Pan-STARRS 1 telescope atop of space.” Haleakala, Maui, is part of NASA’s The Moon and nearby asteroids ground-based near-Earth object offer abundant raw materials, and the search program. NASA’s key first step toward locating and assessing Sun provides nearly limitless energy to asteroid resources should be to power industrial activity in space. The mount a comprehensive survey of president, then, should direct NASA to the hundreds of thousands of expand the $300-billion global space smaller asteroids (about 50 m and up) in accessible, Earth-like sector by using its deep space pro- orbits. Courtesy Rob Ratkowski. grams to actively open the resources of Earth-Moon space to economic development. The millions of NEAs are cosmic leftovers from the formation of the so- lar system, constantly streaming through Earth-Moon space. Asteroid 2012 DA14, for example, passed within Earth’s geosynchronous satel- lite ring on February 15; at 45 m in di- ameter, its mass is about 130,000 met- AEROSPACE AMERICA/MAY 2013 17 VIEW2layout0513_Layout 1 4/15/13 2:56 PM Page 4 launch systems, or harness commer- cial partners to put companies in di- rect contact with space raw materials. First, NASA can announce its in- tention to spur prospecting for space resources by starting a focused search for small asteroids using existing and off-the-shelf ground-based systems, such as the ATLAS search telescope just funded by the agency. It can eval- uate this year and next the practicality of a robotic asteroid capture and re- turn mission (see “Delivering on a promise to Columbia’s explorers,” March, page 14). NASA should initiate a low-cost mission to prospect for ice on the Moon using a commercially built rover and launcher. In parallel, NASA should push ISS experiments testing asteroid surface systems and commercial resource processors aimed at exploiting wate r- NASA astronauts Kevin Ford (foreground), Expedition 34 commander, and Tom Marshburn, flight engineer, bearing NEA regolith when available. worked with the combustion integrated rack multiuser droplet combustion apparatus in the ISS Destiny Within five years, NASA should launch laboratory on January 9. The ISS can host commercial/NASA tests of equipment and processors needed to exploit resources on the low-gravity surfaces of near-Earth asteroids. commercially built asteroid probes to- ward promising NEA targets, with the from Earth. Even a 500-ton asteroid technology goals as it plans to send results guiding development of appro- (about 7 m across) could harbor 100 astronauts to lunar distance and be- priate resource processors. tons of water, worth about $5 billion yond. By fast-tracking physical access The shift to including commercial at today’s launch prices. to in-space resources on both NEAs space activity as a NASA exploration and the Moon, NASA can make the se goal, equal to science and exploration Space resources, step by step materials available not only to astro- technology development, can happen Both companies expect to take at least nauts, but also to commercial industry.
Load more

Recommended publications
  • Ice& Stone 2020
    Ice & Stone 2020 WEEK 34: AUGUST 16-22 Presented by The Earthrise Institute # 34 Authored by Alan Hale This week in history AUGUST 16 17 18 19 20 21 22 AUGUST 16, 1898: DeLisle Stewart at Harvard College Observatory’s Boyden Station in Arequipa, Peru, takes photographs on which Saturn’s outer moon Phoebe is discovered, although the images of Phoebe were not noticed until the following March by William Pickering. Phoebe was the first planetary moon to be discovered via photography, and it and other small planetary moons are discussed in last week’s “Special Topics” presentation. AUGUST 16, 2009: A team of scientists led by Jamie Elsila of the Goddard Space Flight Center in Maryland announces that they have detected the presence of the amino acid glycine in coma samples of Comet 81P/ Wild 2 that were returned to Earth by the Stardust mission 3½ years earlier. Glycine is utilized by life here on Earth, and the presence of it and other organic substances in the solar system’s “small bodies” is discussed in this week’s “Special Topics” presentation. AUGUST 16 17 18 19 20 21 22 AUGUST 17, 1877: Asaph Hall at the U.S. Naval Observatory in Washington, D.C. discovers Mars’ larger, inner moon, Phobos. Mars’ two moons, and the various small moons of the outer planets, are the subject of last week’s “Special Topics” presentation. AUGUST 17, 1989: In its monthly batch of Minor Planet Circulars (MPCs), the IAU’s Minor Planet Center issues MPC 14938, which formally numbers asteroid (4151), later named “Alanhale.” I have used this asteroid as an illustrative example throughout “Ice and Stone 2020” “Special Topics” presentations.
    [Show full text]
  • March 21–25, 2016
    FORTY-SEVENTH LUNAR AND PLANETARY SCIENCE CONFERENCE PROGRAM OF TECHNICAL SESSIONS MARCH 21–25, 2016 The Woodlands Waterway Marriott Hotel and Convention Center The Woodlands, Texas INSTITUTIONAL SUPPORT Universities Space Research Association Lunar and Planetary Institute National Aeronautics and Space Administration CONFERENCE CO-CHAIRS Stephen Mackwell, Lunar and Planetary Institute Eileen Stansbery, NASA Johnson Space Center PROGRAM COMMITTEE CHAIRS David Draper, NASA Johnson Space Center Walter Kiefer, Lunar and Planetary Institute PROGRAM COMMITTEE P. Doug Archer, NASA Johnson Space Center Nicolas LeCorvec, Lunar and Planetary Institute Katherine Bermingham, University of Maryland Yo Matsubara, Smithsonian Institute Janice Bishop, SETI and NASA Ames Research Center Francis McCubbin, NASA Johnson Space Center Jeremy Boyce, University of California, Los Angeles Andrew Needham, Carnegie Institution of Washington Lisa Danielson, NASA Johnson Space Center Lan-Anh Nguyen, NASA Johnson Space Center Deepak Dhingra, University of Idaho Paul Niles, NASA Johnson Space Center Stephen Elardo, Carnegie Institution of Washington Dorothy Oehler, NASA Johnson Space Center Marc Fries, NASA Johnson Space Center D. Alex Patthoff, Jet Propulsion Laboratory Cyrena Goodrich, Lunar and Planetary Institute Elizabeth Rampe, Aerodyne Industries, Jacobs JETS at John Gruener, NASA Johnson Space Center NASA Johnson Space Center Justin Hagerty, U.S. Geological Survey Carol Raymond, Jet Propulsion Laboratory Lindsay Hays, Jet Propulsion Laboratory Paul Schenk,
    [Show full text]
  • Hydrated Minerals on Asteroids: the Astronomical Record
    Hydrated Minerals on Asteroids: The Astronomical Record A. S. Rivkin, E. S. Howell, F. Vilas, and L. A. Lebofsky March 28, 2002 Corresponding Author: Andrew Rivkin MIT 54-418 77 Massachusetts Ave. Cambridge MA, 02139 [email protected] 1 1 Abstract Knowledge of the hydrated mineral inventory on the asteroids is important for deducing the origin of Earth’s water, interpreting the meteorite record, and unraveling the processes occurring during the earliest times in solar system history. Reflectance spectroscopy shows absorption features in both the 0.6-0.8 and 2.5-3.5 pm regions, which are diagnostic of or associated with hydrated minerals. Observations in those regions show that hydrated minerals are common in the mid-asteroid belt, and can be found in unex- pected spectral groupings, as well. Asteroid groups formerly associated with mineralogies assumed to have high temperature formation, such as MAand E-class asteroids, have been observed to have hydration features in their reflectance spectra. Some asteroids have apparently been heated to several hundred degrees Celsius, enough to destroy some fraction of their phyllosili- cates. Others have rotational variation suggesting that heating was uneven. We summarize this work, and present the astronomical evidence for water- and hydroxyl-bearing minerals on asteroids. 2 Introduction Extraterrestrial water and water-bearing minerals are of great importance both for understanding the formation and evolution of the solar system and for supporting future human activities in space. The presence of water is thought to be one of the necessary conditions for the formation of life as 2 we know it.
    [Show full text]
  • ABSTRACT Title of Dissertation: WATER in the EARLY SOLAR
    ABSTRACT Title of Dissertation: WATER IN THE EARLY SOLAR SYSTEM: INFRARED STUDIES OF AQUEOUSLY ALTERED AND MINIMALLY PROCESSED ASTEROIDS Margaret M. McAdam, Doctor of Philosophy, 2017. Dissertation directed by: Professor Jessica M. Sunshine, Department of Astronomy This thesis investigates connections between low albedo asteroids and carbonaceous chondrite meteorites using spectroscopy. Meteorites and asteroids preserve information about the early solar system including accretion processes and parent body processes active on asteroids at these early times. One process of interest is aqueous alteration. This is the chemical reaction between coaccreted water and silicates producing hydrated minerals. Some carbonaceous chondrites have experienced extensive interactions with water through this process. Since these meteorites and their parent bodies formed close to the beginning of the Solar System, these asteroids and meteorites may provide clues to the distribution, abundance and timing of water in the Solar nebula at these times. Chapter 2 of this thesis investigates the relationships between extensively aqueously altered meteorites and their visible, near and mid-infrared spectral features in a coordinated spectral-mineralogical study. Aqueous alteration is a parent body process where initially accreted anhydrous minerals are converted into hydrated minerals in the presence of coaccreted water. Using samples of meteorites with known bulk properties, it is possible to directly connect changes in mineralogy caused by aqueous alteration with spectral features. Spectral features in the mid-infrared are found to change continuously with increasing amount of hydrated minerals or degree of alteration. Building on this result, the degrees of alteration of asteroids are estimated in a survey of new asteroid data obtained from SOFIA and IRTF as well as archived the Spitzer Space Telescope data.
    [Show full text]
  • Astronomical Observations of Volatiles on Asteroids
    Astronomical Observations of Volatiles on Asteroids Andrew S. Rivkin The Johns Hopkins University Applied Physics Laboratory Humberto Campins University of Central Florida Joshua P. Emery University of Tennessee Ellen S. Howell Arecibo Observatory/USRA Javier Licandro Instituto Astrofisica de Canarias Driss Takir Ithaca College and Planetary Science Institute Faith Vilas Planetary Science Institute We have long known that water and hydroxyl are important components in meteorites and asteroids. However, in the time since the publication of Asteroids III, evolution of astronomical instrumentation, laboratory capabilities, and theoretical models have led to great advances in our understanding of H2O/OH on small bodies, and spacecraft observations of the Moon and Vesta have important implications for our interpretations of the asteroidal population. We begin this chapter with the importance of water/OH in asteroids, after which we will discuss their spectral features throughout the visible and near-infrared. We continue with an overview of the findings in meteorites and asteroids, closing with a discussion of future opportunities, the results from which we can anticipate finding in Asteroids V. Because this topic is of broad importance to asteroids, we also point to relevant in-depth discussions elsewhere in this volume. 1 Water ice sublimation and processes that create, incorporate, or deliver volatiles to the asteroid belt 1.1 Accretion/Solar system formation The concept of the “snow line” (also known as “water-frost line”) is often used in discussing the water inventory of small bodies in our solar system. The snow line is the heliocentric distance at which water ice is stable enough to be accreted into planetesimals.
    [Show full text]
  • Voices from the Space Community” No
    “Voices from the Space Community” No. 82 The Need for Strict Regulation of Asteroid Mining Brittany Wojciechowski, Lucas Webb, Aubrey Koonce, Molly Williams Wichita State University We argue that while asteroid mining should be pursued, it should come with strict restrictions so as not to allow monopolies or depletion of asteroidal resources. We propose an international regulatory framework between countries wishing to participate in mining, an asteroid land rental fee, a rental time limit, and a space “customs” which inventories materials brought back to Earth. We agree with the UN that there should be special attention given to countries that lack space technology, and that arrangements should be made that will benefit them, such as aiding in funding their space programs or sharing the resources brought back from space. This paper produces a rough framework of a possible policy that should be considered as more formal asteroid mining policies take shape. 1 Introduction 2 Asteroid Mining Benefits For asteroid mining to be a possibility, frameworks Concerns of human exhaustion of Earth’s need to be built and current space treaties need to resources have grown more serious in recent years be revisited. If there are no explicit frameworks in due to the development of new technologies place, then investors are less likely to support allowing the extraction of more resources at a asteroid mining initiatives, leading to the stagnation higher rate. Eventually, non-renewable, but of asteroid mining efforts. This would be important resources, such as platinum as well as unfortunate, because there are numerous benefits other mineral resources, will be depleted either of asteroid mining.
    [Show full text]
  • Untangling the Formation and Liberation of Water in the Lunar Regolith
    Untangling the formation and liberation of water in the lunar regolith Cheng Zhua,b,1, Parker B. Crandalla,b,1, Jeffrey J. Gillis-Davisc,2, Hope A. Ishiic, John P. Bradleyc, Laura M. Corleyc, and Ralf I. Kaisera,b,2 aDepartment of Chemistry, University of Hawai‘iatManoa, Honolulu, HI 96822; bW. M. Keck Laboratory in Astrochemistry, University of Hawai‘iatManoa, Honolulu, HI 96822; and cHawai‘i Institute of Geophysics and Planetology, University of Hawai‘iatManoa, Honolulu, HI 96822 Edited by Mark H. Thiemens, University of California at San Diego, La Jolla, CA, and approved April 24, 2019 (received for review November 15, 2018) −8 −6 The source of water (H2O) and hydroxyl radicals (OH), identified between 10 and 10 torr observed either an ν(O−H) stretching − − on the lunar surface, represents a fundamental, unsolved puzzle. mode in the 2.70 μm (3,700 cm 1) to 3.33 μm (3,000 cm 1) region The interaction of solar-wind protons with silicates and oxides has exploiting infrared spectroscopy (7, 25, 26) or OH/H2Osignature been proposed as a key mechanism, but laboratory experiments using secondary-ion mass spectrometry (27) and valence electron yield conflicting results that suggest that proton implantation energy loss spectroscopy (VEEL) (28). However, contradictory alone is insufficient to generate and liberate water. Here, we dem- studies yielded no evidence of H2O/OH in proton-bombarded onstrate in laboratory simulation experiments combined with minerals in experiments performed under ultrahigh vacuum − − imaging studies that water can be efficiently generated and re- (UHV) (10 10 to 10 9 torr) (29).
    [Show full text]
  • Hydrated Minerals on Asteroids 235
    Rivkin et al.: Hydrated Minerals on Asteroids 235 Hydrated Minerals on Asteroids: The Astronomical Record A. S. Rivkin Massachusetts Institute of Technology E. S. Howell Arecibo Observatory F. Vilas NASA Johnson Space Center L. A. Lebofsky University of Arizona Knowledge of the hydrated mineral inventory on the asteroids is important for deducing the origin of Earth’s water, interpreting the meteorite record, and unraveling the processes occurring during the earliest times in solar system history. Reflectance spectroscopy shows absorption features in both the 0.6–0.8 and 2.5–3.5-µm regions, which are diagnostic of or associated with hydrated minerals. Observations in those regions show that hydrated minerals are common in the mid-asteroid belt, and can be found in unexpected spectral groupings as well. Asteroid groups formerly associated with mineralogies assumed to have high-temperature formation, such as M- and E-class asteroids, have been observed to have hydration features in their reflectance spectra. Some asteroids have apparently been heated to several hundred degrees Celsius, enough to destroy some fraction of their phyllosilicates. Others have rotational variation suggesting that heating was uneven. We summarize this work, and present the astronomical evidence for water- and hydroxyl-bearing minerals on asteroids. 1. INTRODUCTION to be common. Indeed, water is found throughout the outer solar system on satellites (Clark and McCord, 1980; Clark Extraterrestrial water and water-bearing minerals are of et al., 1984), Kuiper Belt Objects (KBOs) (Brown et al., great importance both for understanding the formation and 1997), and comets (Bregman et al., 1988; Brooke et al., 1989) evolution of the solar system and for supporting future as ice, and on the planets as vapor (Larson et al., 1975; human activities in space.
    [Show full text]
  • Inner Solar System Material Discovered in the Oort Cloud
    Inner Solar System Material Discovered in the Oort Cloud Karen J. Meech1,, Bin Yang,2, Jan Kleyna1, Olivier R. Hainaut,3, Svetlana Berdyugina1,4, Jacqueline V. Keane3, Marco Micheli5-7, Alessandro Morbidelli8, Richard J. Wainscoat1 Teaser: Fresh inner solar systeM Material preserved in the Oort cloud May hold the key to understanding our solar systeM forMation 1Institute for AstronoMy, University of Hawai’i, 2680 Woodlawn Drive, Honolulu, Hawaii 96822-1839, USA. 2European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago, Chile 3European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Munchen, GerMany 4Kiepenheuer Institut fuer Sonnenphysik, Schoeneckstrasse 6, 79104 Freiburg, GerMany 5SSA NEO Coordination Centre, European Space Agency, 00044 Frascati (RM), Italy 6SpaceDyS s.r.l., 56023 Cascina (Pl), Italy 7INAF-IAPS, 00133 RoMa (RM), Italy 8Laboratoire Lagrange, UMR7293, Universite de Nice Sophia-Antipolis, CNRS, Obs. de la Cote d'Azur, Boulevard de l'Observatoire, 06304 Nice Cedex 4, France Manuscript subMitted to Science Advances: Revised, 2016-02-28 Total pages including abstract, text, references, table and figures captions: 21 Total words (abstract): 200 Total words (body text): 2692 Total References for paper + suppleMent: 56 1 We have observed C/2014 S3 (PANSTARRS), a recently discovered object on a coMetary orbit coming from the Oort cloud that is physically siMilar to an inner Main belt rocky S-type asteroid. Recent dynamical Models succeed in reproducing key characteristics of our current solar systeM; some of these Models require significant Migration of the giant planets, while others do not. These Models provide different predictions on the presence of rocky Material expelled froM the inner Solar SysteM in the Oort cloud.
    [Show full text]
  • Cosmoelements AQUEOUS ALTERATION
    CosmoELEMENTS AQUEOUS ALTERATION AND ACCRETION OF CHONDRITE PARENT BODIES: WHEN AND WHERE?1 Patricia M. Doyle2,3 Alexander N. Krot2 and Team4 1811-5209/16/0xxx-$0.00 DOI: 10.2113/gselements.12.5.368 Astronomical observations indicate that the S-type asteroids are concentrated in the inner portion of the main asteroid belt, whereas Events such as the Shoemaker−Levy 9 comet impact into Jupiter (July the C-type asteroids are predominantly located in its outer region. Has 1994) and the Chelyabinsk meteorite impact in Russia (February 2013) this pattern existed since their accretion? Or were hydrated, C-type are reminders of the dynamic processes that were part of the formation asteroids accreted beyond Jupiter and subsequently implanted into the of our Solar System from a protosolar molecular cloud of interstellar and outer regions of the asteroid belt (e.g. Walsh et al. 2011)? There is no circumstellar dust and gas. High-temperature (up to 2000 K) transient easy answer, but one may glean insight from the accretion age of the heating events (e.g. shock waves, current sheets, lightning, etc.) resulted chondrite bodies in relation to the predicted position of the snow line in thermal processing (evaporation, condensation, and melting) of the over time. primordial molecular cloud matter. In general, however, the ambient temperature of the disk decreased radially from the proto-Sun. When Minerals such as phyllosilicates [sheet silicates], carbonates temperatures fell below 160 K, water vapor condensed directly into [(Ca,Mg,Fe,Mn)CO3], magnetite (Fe3O4), fayalite (Fe2SiO4), kirschsteinite water ice, forming a front known as the “snow line”.
    [Show full text]
  • Comet Hazard to the Earth
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by CERN Document Server COMET HAZARD TO THE EARTH S. I. Ipatov Institute of Applied Mathematics, Miusskaya sq. 4, Moscow 125047, Russia; [email protected] ABSTRACT Migration of trans-Neptunian objects to the Earth is considered. Due to the gravitational influence of large trans-Neptunian objects and mutual collisions, some objects can get such orbits, from which they can be moved inside the Solar System under the gravitational influence of planets. About 10-20% or even more 1-km Earth-crossers could have come from the Edgeworth-Kuiper belt and can move in Jupiter-crossing orbits. The number of former trans-Neptunian objects that cross the Earth’s orbit moving in orbits with aphelia inside Jupiter’s orbit can be of the same order of magnitude. A total mass of icy planetesimals delivered to the Earth during formation of the giant planets can be about the mass of the Earth’s oceans. Keywords: trans-Neptunian objects, near-Earth objects, migration Paper submitted to ”Advances in Space Research” (in press). INTRODUCTION Near-Earth objects (NEOs), i.e., objects with perihelion distance q 1:3 AU and aphelion distance ≤ Q 0:983 AU, are considered to have a chance to collide the Earth in some future. There are more than 30≥ NEOs larger than 5 km in diameter, about 1500 NEOs larger than 1 km, and 135,000 larger than 100 m (Rabinowitz et al., 1994). About half of NEOs are Earth-crossers. It is considered that diameter of the object that caused the Tunguska event in 1908 was about 60-70 m.
    [Show full text]
  • Mccoy, T. J. Mineralogical Evolution of Meteorites. Elements
    Mineralogical Evolution of Meteorites Halite crystals from the Monahans chondrite contain fl uid inclusions, which indicate Timothy J. McCoy* signifi cant water–rock interactions in the 1811-5209/10/0006-0019$2.50 DOI: 10.2113/gselements.6.1.19 meteorite’s parent body. Image width ~5 mm. COURTESY OF M. he approximately 250 mineral species found in meteorites record the ZOLENSKY AND R. BODNAR earliest stages of the birth of our solar system. Refractory minerals but eventually transformed some that formed during the violent deaths of other stars and during conden- T asteroids into molten worlds that sation of our own solar nebula mixed with a wide range of silicates, sulfi des, formed crusts, mantles, and cores and metals to form the most primitive chondritic meteorites. Subsequent reminiscent of our own planet. It aqueous alteration, thermal metamorphism, and shock metamorphism further is this history—from the earliest beginnings to the melting of diversifi ed the minerals found in meteorites. Asteroidal melting at fi rst planets—that we explore in this increased and then dramatically decreased mineralogical diversity, before a article. new phase of igneous differentiation that presaged the processes that would occur in terrestrial planets. THE STELLAR CAULDRON Earth’s mineralogical evolution KEYWORDS: mineral evolution, meteorites, asteroids, metamorphism, began not in the heat of an early differentiation, shock molten planet but in the blast furnace of stars that predated our FRAGMENTS FROM THE BEGINNING solar system. More than 4.6 billion years ago, presolar As Earth evolved over the last 4.5 billion years, its miner- grains formed when temperatures in the expanding enve- alogy changed.
    [Show full text]