DOCSLIB.ORG

Development of Methods for Navigational Referencing of Circumlunar Spacecrafts to the Selenocentric Dynamic Coordinate System A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Development of Methods for Navigational Referencing of Circumlunar Spacecrafts to the Selenocentric Dynamic Coordinate System A ISSN 1063-7729, Astronomy Reports, 2020, Vol. 64, No. 9, pp. 795–803. © Pleiades Publishing, Ltd., 2020. Russian Text © The Author(s), 2020, published in Astronomicheskii Zhurnal, 2020, Vol. 97, No. 9, pp. 765–775. Development of Methods for Navigational Referencing of Circumlunar Spacecrafts to the Selenocentric Dynamic Coordinate System A. O. Andreeva, b, c, Yu. A. Nefedyeva, *, N. Yu. Deminaa, L. A. Nefedieva, N. K. Petrovac, and A. A. Zagidullina a Kazan Federal University, Kazan, 420008 Tatarstan, Russia b Sternberg Astronomical Institute, Moscow State University, Moscow, 119992 Russia c Kazan State Power Engineering University, Kazan, 420066 Tatarstan, Russia *e-mail: [email protected] Received December 19, 2019; revised January 24, 2020; accepted January 24, 2020 Abstract—The initial form of present-day space optical observations contain considerable geometrical and brightness distortions. This problem can be solved based on geometrical correction and transformation of ref- erence object coordinates into commonly accepted cartographic projections. In this work, the method of coordinate transformation to the reference selenocentric dynamic system by using a base of reference sele- nographic objects as electronic maps is considered. The transformation process presupposes the formation of a photogrammetrically corrected image and identification of observed objects included into the electronic maps. Height data of on the Moon’s surface are determined from known observed selenographic coordinates with respect to reference objects by software tools. Preliminary selenographic coordinates can be determined using both ground positional observations and onboard goniometric devices such as a laser interferometer. DOI: 10.1134/S1063772920100017 1. INTRODUCTION for the determination of its position in the phase space In the field of carrying out the system analysis of are related to results of Doppler ground tracking, car- selenophysical data from present-day lunar missions, ried out mainly with the use of the DSN system developing the method for reducing different seleno- (NASA Deep Space Network). Referencing to the physical observations to a common selenocentric sys- DSN system is insufficiently exact, both relative to the tem, and creating a digital catalog of selenocentric ref- celestial coordinate system and to the Earth’s coordi- erence points, one should note the following [1]. At nate systems. Results presented by Konopliv et al. [3] present, in spite of achievements in the determination on laser altimetry of the Moon’s surface and structural of selenophysical parameters based on measurement elements of the Moon’s selenoid are also not refer- data from spacecrafts, the problem of creating exact enced to any specific coordinate system but only ori- coordinate–time orientation on the Moon’s surface ented in a certain way with respect to the Moon’s posi- remains unsolved to a certain degree. According to [2], tion. Each spacecraft revolution around the celestial a conclusion exists that orbital parameters of the body corresponds to a certain orbit. Based on element GRAIL and LRO lunar missions were determined and differences of such orbits at points at which the orbits referenced to the celestial coordinate system with an intersect, the accuracy of coordinate–time referenc- accuracy of 1 m throughout the whole route of the sat- ing for the circumlunar satellite is estimated. In this ellite flight. This conclusion is based on that images case, the determination of an adequate internal accu- received from the LRO board were referenced to each racy of the orbital motion can be discussed. Using other with this accuracy for selenographic coordinates present-day altimetric space measurements and con- when every pixel corresponds to 0.5 m on the Moon’s sidering gravity perturbations improves the matching surface. It is also believed that the gravity field model of orbital parameters and increases the internal accu- constructed by GRAIL measurements is everywhere racy. Still, this does not allow one to estimate the equated and matched with orbital elements of the external accuracy of coordinate–time referencing. LRO mission. However, according to [3] in which Therefore, the described technique can be used only in observations obtained by the LRO spacecraft are ana- the case where the satellite orbits are referenced to lyzed, almost all data on scanning the lunar satellite each other. The LRO mission is also not an exception. 795 796 ANDREEV et al. North Z η M R O +β ξ East Y +λ M ' ζ X Fig. 1. Systems of selenographic coordinates. Estimation of the external accuracy requires support is referencing to a system of light laser beacons another kind of observational data whose accuracy is (LLBs). Such system is similar to the system of refer- not worse than the internal accuracy. Referencing of ence lunar craters; however, the latter are point objects the spacecraft to stars and objects on the Moon’s sur- with which one can implement in principle coordinate face can serve as such observations [4]. In this work, a referencing with an accuracy equal to several centime- method of regression modeling for reducing different ters using the method developed in this work. It is selenophysical measurements to a common seleno- planned to set up such beacons in the course of Rus- centric system and constructing the digital selenocen- sian Luna-25 (26, 27, and 28) lunar missions. Using tric catalog (DSC) of reference lunar objects based on LLBs will make it possible to implement high-accu- their direct referencing to stars and transformation of racy lunar landing and to perform highly detailed data from present-day lunar missions into the DSC scanning of the Moon. In the process of navigational system is proposed. The described results, with allow- referencing of space satellites to the lunar coordinate ance for new theories of physical libration of the system, our method allows one to use both objects Moon, allow one to create a dynamic selenocentric with known coordinates on the Moon’s surface and reference system with coordinate axes that coincide quantum optical systems for which LLBs with deter- with the lunar axes of the Moon’s inertia and the coor- mined exact coordinate positions serve as analogues. dinate origin coincides with the Moon’s center of mass. It should be noted that the first attempt of navi- gational referencing to the digital selenographic cata- 2. SELENOGRAPHIC COORDINATE SYSTEM log in the world practice was made by measurement When creating the reference catalog of lunar systems of the LRO mission. On the platform of this objects of the visible and hidden sides of the Moon spacecraft, the LALT measurement system was (CLO), it is necessary to exactly determine the coordi- mounted. LALT included the LROC main optical nate systems in which all constructions will be per- camera allowing one to obtain lunar surface images formed because there are certain disagreements in the with a resolution of 0.5 m and LOLA altimeter for the special literature on this subject. The rectangular sele- creation of an exact map of height data. The LALT nographic coordinates are reckoned in fractions of the system was used with the aim of determining the most Moon radius R = 1738.1 km. suitable locations for lunar landing of modules of The direction of the axes is as follows (see Fig. 1): future lunar missions. Special attention in implement- ζ is directed to the Earth (x in the Cartesian coordi- ing the LRO project was directed to the increase in the nate system); ξ coincides with the projection of the accuracy of finding the satellite orbit elements. lunar equator and is directed to the East (y in the Car- η High resolution images covering the given lunar tesian coordinate system); and coincides with the territories were obtained using a special panoramic projection of the zero meridian and is directed to the camera. Based on photogrammetric methods and spe- North Pole (z in the Cartesian coordinate system). cial software, an attempt was made to reference the The meridian passing through the first lunar satellite orbit to the digital reference catalog of lunar radius, i.e., through the axis of inertia X , has the lon- objects. A promising direction of coordinate–time gitude of 0°. ASTRONOMY REPORTS Vol. 64 No. 9 2020 DEVELOPMENT OF METHODS FOR NAVIGATIONAL REFERENCING 797 The longitude is reckoned in degrees. According to allows one to increase the accuracy of the transforma- classics of selenography [5, 6], the selenographic lon- tion of selenocentric coordinates more than by 10%. gitude of a point is equal to the dihedral angle between 2. Affine transformation method. This approach is the zero meridian and meridian of the crater. It is pos- used for the transformation of selenocentric coor- itive in the eastern hemisphere and negative in the western hemisphere of the Moon. In both directions, dinates from one Cartesian system X to another sys- longitudes increase to 180° in the first case and tem Y. decrease to –180° in the second case. The meridian of ° The efficiency of the procedures used in the trans- 180 passes through the center of the hidden side of the formation of selenocentric coordinates is determined Moon and traverses Mare Ingenii. However, accord- using the exact comparative analysis. Such procedures ing to [7], the definition is presented incorrectly— include. positive longitudes are reckoned to the West from the zero meridian and negative ones to the East. There- 1. Optimization of polynomial approximations. fore, one must be attentive to publications and defini- 2. Affine transformations. tions which are presented in different sources because a large number of scientific works were published later 3. Orthogonal transformations with enumeration based on them. of systematic errors. The latitude is reckoned in degrees. The arc reck- 4. Solution of linear equation systems. oned from the equator along the meridian passing Different observations of coordinate positions were through the crater to crater is called the latitude.
Load more

Recommended publications
  • Glossary of Lunar Terminology
    Glossary of Lunar Terminology albedo A measure of the reflectivity of the Moon's gabbro A coarse crystalline rock, often found in the visible surface. The Moon's albedo averages 0.07, which lunar highlands, containing plagioclase and pyroxene. means that its surface reflects, on average, 7% of the Anorthositic gabbros contain 65-78% calcium feldspar. light falling on it. gardening The process by which the Moon's surface is anorthosite A coarse-grained rock, largely composed of mixed with deeper layers, mainly as a result of meteor­ calcium feldspar, common on the Moon. itic bombardment. basalt A type of fine-grained volcanic rock containing ghost crater (ruined crater) The faint outline that remains the minerals pyroxene and plagioclase (calcium of a lunar crater that has been largely erased by some feldspar). Mare basalts are rich in iron and titanium, later action, usually lava flooding. while highland basalts are high in aluminum. glacis A gently sloping bank; an old term for the outer breccia A rock composed of a matrix oflarger, angular slope of a crater's walls. stony fragments and a finer, binding component. graben A sunken area between faults. caldera A type of volcanic crater formed primarily by a highlands The Moon's lighter-colored regions, which sinking of its floor rather than by the ejection of lava. are higher than their surroundings and thus not central peak A mountainous landform at or near the covered by dark lavas. Most highland features are the center of certain lunar craters, possibly formed by an rims or central peaks of impact sites.
    [Show full text]
  • IWLOP Logbook
    Isabel Williamson Lunar Observing Logbook The certificate applicant must use this logbook (or an equivant means) to qualify. Enter the date, time, and other details for each observation as indicated. The R (required) objectives are mandatory; the C (challenge) objectives are optional. Sketch drawings are also optional, but encouraged. Use the small template provided, or the larger one found on p. 84 of this logbook. PART 1 – Introducing the Moon A – Lunar Phases and Orbital Motion R 1 – Enter in the notes section the date and time for each phase observed. R 2 – Date _________________ Time__________________ R 3 – Date _________________ Time__________________ Date _________________ Time__________________ Notes _________________________________________________ _________________________________________________ _________________________________________________ _________________________________________________ B – Major Basins (Maria) & Pickering Unaided Eye Scale R 1 – Date __________________ Time__________________ C 1 – Date __________________ Time__________________ C 2 – Date __________________ Time__________________ Notes (see p. 81 of this logbook for optional Pickering Unaided Eye Scale) __________________________________________________ __________________________________________________ __________________________________________________ __________________________________________________ C – Ray System Extent R 1 – Date ___________________ Time_________________ C 1 – Date ___________________ Time_________________ Notes (see p. 82 of this
    [Show full text]
  • Enceladus's Measured Physical Libration Requires a Global Subsurface Ocean
    Enceladus’s measured physical libration requires a global subsurface ocean P. C. Thomas1*, R. Tajeddine1, M. S. Tiscareno1,2, J. A. Burns1,3, J. Joseph1, T. J. Loredo1 , P. Helfenstein1, C. Porco4, 1Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14853 USA 2Carl Sagan Center for the Study of Life in the Universe, SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043 3College of Engineering, Cornell University, Ithaca, NY 14853 USA 4Space Science Institute, Boulder, CO 80304, USA *Corresponding author E-mail:[email protected] Several planetary satellites apparently have subsurface seas that are of great interest for, among other reasons, their possible habitability. The geologically diverse Saturnian satellite Enceladus vigorously vents liquid water and vapor from fractures within a south polar depression and thus must have a liquid reservoir or active melting. However, the extent and location of any subsurface liquid region is not directly observable. We use measurements of control points across the surface of Enceladus accumulated over seven years of spacecraft observations to determine the satellite’s precise rotation state, finding a forced physical libration of 0.120 ± 0.014° (2σ). This value is too large to be consistent with Enceladus’s core being rigidly connected to its surface, and thus implies the presence of a global ocean rather than a localized polar sea. The maintenance of a global ocean within Enceladus is problematic according to many thermal models and so may constrain satellite properties or require a surprisingly dissipative Saturn. 1. Introduction Enceladus is a 500-km-diameter satellite of mean density 1609 ± 5 kg-m-3 orbiting Saturn every 1.4 days in a slightly eccentric (e = 0.0047) orbit (Porco et al., 2006).
    [Show full text]
  • Ages of Large Lunar Impact Craters and Implications for Bombardment During the Moon’S Middle Age ⇑ Michelle R
    Icarus 225 (2013) 325–341 Contents lists available at SciVerse ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Ages of large lunar impact craters and implications for bombardment during the Moon’s middle age ⇑ Michelle R. Kirchoff , Clark R. Chapman, Simone Marchi, Kristen M. Curtis, Brian Enke, William F. Bottke Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302, United States article info abstract Article history: Standard lunar chronologies, based on combining lunar sample radiometric ages with impact crater den- Received 20 October 2012 sities of inferred associated units, have lately been questioned about the robustness of their interpreta- Revised 28 February 2013 tions of the temporal dependance of the lunar impact flux. In particular, there has been increasing focus Accepted 10 March 2013 on the ‘‘middle age’’ of lunar bombardment, from the end of the Late Heavy Bombardment (3.8 Ga) until Available online 1 April 2013 comparatively recent times (1 Ga). To gain a better understanding of impact flux in this time period, we determined and analyzed the cratering ages of selected terrains on the Moon. We required distinct ter- Keywords: rains with random locations and areas large enough to achieve good statistics for the small, superposed Moon, Surface crater size–frequency distributions to be compiled. Therefore, we selected 40 lunar craters with diameter Cratering Impact processes 90 km and determined the model ages of their floors by measuring the density of superposed craters using the Lunar Reconnaissance Orbiter Wide Angle Camera mosaic. Absolute model ages were computed using the Model Production Function of Marchi et al.
    [Show full text]
  • LROC-LOLA-Mapping the Surface of the Moon
    Lunar Reconnaissance Orbiter: (LROC/ LOLA) Audience Mapping The Surface Grades 5-12 of the Moon Time Recommended 30-45 Minutes Per Activity (Lesson contains 5 activities) AAAS STANDARDS Learning Objectives: • 1B/1: Scientific investigations usually involve the col- • Able to correctly identify, observe, record, illustrate and label important geo- lection of relevant evidence, the use of logical reasoning, logic features on the Moon. and the application of imagination in devising hypoth- • Able to describe and explain the types of geologic features found on the eses and explanations to make sense of the collected evidence. Moon, how they formed, and how those features compare with like features on Earth. • 3A/M2: Technology is essential to science for such purposes as access to outer space and other remote • Able to accurately measure and calculate scale and distance relationships for locations,sample collection and treatment, measurement, specific geologic features on the Moon relative to a feature, or between and datacollection and storage, computation, and communi - among features. cation of information • Able to successfully reconstruct, record and explain the geologic history of NSES STANDARDS Content Standard A (5-8): Abilities necessary to do scien- specific areas on the lunar surface through identification of geologic features tific inquiry: and identification of relationships evident among features, using the basic c. Use appropriate tools to gather, analyze and inter- principles of geology and evidence found in the data; especially those related pret data. to the principles of superposition and cross-cutting. d. Develop descriptions and explanations using • Able to identify and explain the technological advances evidenced when evidence.
    [Show full text]
  • 2020-03-23T15:27:49+00:00Z Comparative Analyses of Observations
    https://ntrs.nasa.gov/search.jsp?R=19710021616 2020-03-23T15:27:49+00:00Z COMPARATIVE ANALYSES OF OBSERVATIONS OF LUNAR TRANSIENT PHENOMENA Winifred Sawtell Cameron Laboratory for Space Physics NASA-Goddard Space Flight Center Greenbelt, Maryland 20771 January 1971 GODDARD SPACE FLIGHT CENTER Greenbelt, Maryland COMPARATIVE ANALYSES OF OBSERVATIONS OF LUNAR TRANSIENT PHENOMENA Winifred Sawtell Cameron Laboratory for Space Physics NASA-Goddard Space Flight Center Greenbelt, Maryland 2 0771 ABSTRACT A collection of > 800 reports of lunar transient phenomena (LTP) etsntained 771 positive and 112 negative observations with sufficient ancillary data. to be analyzed for five hypotheses of causes. Greater than one third of these reports involve Aristarchus, divided almost equally between two observing g;rsups, One homogeneous group involved one observer, Bartlett, and the other, heterogeneous group comprised all other observers. These two groups plus their ~=ombiaaation were each separately analyzed for each hypothesis for Aristarchus ., The obser- vations seemed to form four categories, viz. (1) gaseous, (2) reddislh, (3) bluish, and (4) colorless brightenings and were analyzed under each category for each hypothesis and group, as well as the total Aristarchus and total of a.l.1 sites which were analyzed for each hypothesis. Each and all were compared. The five hy- potheses involved the effects of (1) tides, (2) sunrise, (3) low-angle i8lumiwtion, (4) earth's magnetic tail, and (5) solar particles. The analytical results for Aristarchus suggest the following: (1) ga.sesus phenomena of Bartlett differed in analytical behavior from those of all. others; (2) Bartlett's reddish phenomena differed from all others, being seen at times when gaseous phenomena were not present, suggesting he saw ground color in iii the absence of events of an obscuring medium.
    [Show full text]
  • Morphometric Characterization and Reconstruction Effect Among Lunar Impact Craters
    Earth Moon Planets (2014) 111:139–155 DOI 10.1007/s11038-014-9431-0 Morphometric Characterization and Reconstruction Effect Among Lunar Impact Craters Weiming Cheng • Jiao Wang • Cong Wan Received: 2 January 2014 / Accepted: 11 March 2014 / Published online: 19 March 2014 Ó Springer Science+Business Media Dordrecht 2014 Abstract Impact craters on the lunar surface have a variety of morphometric charac- teristics that are very useful in understanding the evolutionary history of lunar landscape morphologies. Based on digital elevation model data and photographs from China’s Chang’E-1 lunar orbiter, we develop morphologic parameters and quantitative methods for presenting the morphometric characteristics of impact craters, analyzing their relational distribution, and estimating the relative order of their formation. We also analyze features in profile where craters show signs of having formed on the edge of previously existing craters to show that superimposed impacts affect morphologic reconstructions. As a result, impact craters have significant effects on the reconstruction of ancient topography and the estimation of relative formation ages. Keywords Morphometric characterization Á Position relationship Á Relative construction age Á Chang’E-1 1 Introduction The Earth’s Moon, it’s only natural satellite, has a potentially complete record of the 4.5- billion year evolutionary history of the solar system (Ronca 1966; Ouyang 2005). Impact craters are the most obvious and typical geomorphologic units (Ronca 1969; Neukum and Ivanov 1994; Neukum et al. 1975); they form when a planetary body (meteoro, comet, etc.) impact against the surface (King 1976). The diameters of impact craters on the lunar W. Cheng (&) Á J.
    [Show full text]
  • U.S. Government Publishing Office Style Manual
    Style Manual An official guide to the form and style of Federal Government publishing | 2016 Keeping America Informed | OFFICIAL | DIGITAL | SECURE [email protected] Production and Distribution Notes This publication was typeset electronically using Helvetica and Minion Pro typefaces. It was printed using vegetable oil-based ink on recycled paper containing 30% post consumer waste. The GPO Style Manual will be distributed to libraries in the Federal Depository Library Program. To find a depository library near you, please go to the Federal depository library directory at http://catalog.gpo.gov/fdlpdir/public.jsp. The electronic text of this publication is available for public use free of charge at https://www.govinfo.gov/gpo-style-manual. Library of Congress Cataloging-in-Publication Data Names: United States. Government Publishing Office, author. Title: Style manual : an official guide to the form and style of federal government publications / U.S. Government Publishing Office. Other titles: Official guide to the form and style of federal government publications | Also known as: GPO style manual Description: 2016; official U.S. Government edition. | Washington, DC : U.S. Government Publishing Office, 2016. | Includes index. Identifiers: LCCN 2016055634| ISBN 9780160936029 (cloth) | ISBN 0160936020 (cloth) | ISBN 9780160936012 (paper) | ISBN 0160936012 (paper) Subjects: LCSH: Printing—United States—Style manuals. | Printing, Public—United States—Handbooks, manuals, etc. | Publishers and publishing—United States—Handbooks, manuals, etc. | Authorship—Style manuals. | Editing—Handbooks, manuals, etc. Classification: LCC Z253 .U58 2016 | DDC 808/.02—dc23 | SUDOC GP 1.23/4:ST 9/2016 LC record available at https://lccn.loc.gov/2016055634 Use of ISBN Prefix This is the official U.S.
    [Show full text]
  • Physics of the Moon
    NASA TECHNICAL NOTE -cNASA TN D-2944 e. / PHYSICS OF THE MOON SELECTED TOPICS CONCERNING LUNAR EXPLORATION Edited by George C. ‘Bucker and Henry E. Siern George C. Marsball Space Flight Center Hzmtsville, A Za: NATIONAL AERONAUTICSAND SPACEADMINISTRATION - WASHINGTON;D. C. TECH LIBRARY KAFB. NM llL5475b NASA TN D-2944 PHYSICS OF THE MOON SELECTED TOPICS CONCERNING LUNAR EXPLORATION Edited by George C. Bucher and Henry E. Stern George C. Marshall Space Flight Center Huntsville, Ala. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION For sole by the Clearinghouse for Federal Scientific and Technical information Springfield, Virginia 22151 - Price 56.00 I - TABLE OF CONTENTS Page SUMMA=. 1 INTRODUCTION. i SECTION I. CHARACTERISTICS OF THE MOON. i . 3 Chapter 1. The Moon’s .History, by Ernst Stuhlinger. 5 Chapter 2. Physical Characteristics of the Lunar Surface, by John Bensko . 39 Chapter 3. The’ Lunar Atmosphere, by Spencer G. Frary . , 55 Chapter 4. Energetic Radiation Environment of the Moon, by Martin 0. Burrell . 65 Chapter 5. The Lunar Thermal Environment , . 9i The Thermal Model of the Moon, by Gerhard B. Heller . 91 p Thermal Properties of the Moon as a Conductor of Heat,byBillyP. Jones.. 121 Infrared Methods of Measuring the Moon’s Temperature, by Charles D. Cochran. 135 SECTION II. EXPLORATION OF THE MOON . .I59 Chapter I. A Lunar Scientific Mission, by Daniel Payne Hale. 161 Chapter 2. Some Suggested Landing Sites for Exploration of the Moon, by Daniel Payne Hale. 177 Chapter 3. Environmental Control for Early Lunar Missions, by ‘Herman P. Gierow and James A. Downey, III . , . .2i I Chapter 4.
    [Show full text]
  • Galileo Imaging Results from the Second Earth-Moon Flyby: Lunar Maria and Related Units; R
    GALILEO IMAGING RESULTS FROM THE SECOND EARTH-MOON FLYBY: LUNAR MARIA AND RELATED UNITS; R. Greeley(l1, M.J.S. Beltod2), J.W. ~ead(3), A.S. ~c~wen(~),C.M. ~ieters(3), G. Neukurn(51, T.L. ~ecked~),E. M. Fisched3), S. D. Kadel(l), M.S. ~obinson(6),R.J. Sullivan(l), J.M. Sunshine(3), and D.A. Williams(1). (1) Arizona State University, Tempe, AZ; (2)NOAO, Tucson, AZ; (3)Brown University, Providence, RI; (4) U.S. Geological Survey, Flagstafl AZ; (5) German Aerospace Research Establishment (DLR), Inst. for Planetary Exploration, BerlidOberpfaffenhofen, Germany; (6) University of Hawaii, Honolulu, HI. The second flyby of the Earth-Moon System by Galileo occurred on December 7, 1992, on its trajectory toward Jupiter. The flyby took the spacecraft over the lunar north polar region from the dark farside and continued across the illuminated nearside. This provided the first opportunity to observe northern and northeastern limb regions with a modem, multispectral imaging system [l] with high spatial resolution (up to 1.1 kdpixel). Scientific objectives included compositional assessment of previously uncharacterized mare regions, study of various light plains materials, and assessment of dark mantle deposits (DMD) and dark halo craters (DHC). Color composite images were prepared from ratios of Galileo SSI filter data (0.76/0.41+ red; 0.7610.99 + green; 0.4110.76 + blue) and used for preliminary comparison of units [2]. The 0.4110.76 ratio has been empirically correlated to Ti content of mare soils (blue is relatively high, red is relatively low) [3]. The relative strengths of the ferrous one micron absorption in mafic minerals can be compared using the 0.7610.99 ratio.
    [Show full text]
  • Mars: an Introduction to Its Interior, Surface and Atmosphere
    MARS: AN INTRODUCTION TO ITS INTERIOR, SURFACE AND ATMOSPHERE Our knowledge of Mars has changed dramatically in the past 40 years due to the wealth of information provided by Earth-based and orbiting telescopes, and spacecraft investiga- tions. Recent observations suggest that water has played a major role in the climatic and geologic history of the planet. This book covers our current understanding of the planet’s formation, geology, atmosphere, interior, surface properties, and potential for life. This interdisciplinary text encompasses the fields of geology, chemistry, atmospheric sciences, geophysics, and astronomy. Each chapter introduces the necessary background information to help the non-specialist understand the topics explored. It includes results from missions through 2006, including the latest insights from Mars Express and the Mars Exploration Rovers. Containing the most up-to-date information on Mars, this book is an important reference for graduate students and researchers. Nadine Barlow is Associate Professor in the Department of Physics and Astronomy at Northern Arizona University. Her research focuses on Martian impact craters and what they can tell us about the distribution of subsurface water and ice reservoirs. CAMBRIDGE PLANETARY SCIENCE Series Editors Fran Bagenal, David Jewitt, Carl Murray, Jim Bell, Ralph Lorenz, Francis Nimmo, Sara Russell Books in the series 1. Jupiter: The Planet, Satellites and Magnetosphere Edited by Bagenal, Dowling and McKinnon 978 0 521 81808 7 2. Meteorites: A Petrologic, Chemical and Isotopic Synthesis Hutchison 978 0 521 47010 0 3. The Origin of Chondrules and Chondrites Sears 978 0 521 83603 6 4. Planetary Rings Esposito 978 0 521 36222 1 5.
    [Show full text]
  • Extraction of Mercury's Tidal Signal and Libration Amplitude from Synthetic Laser Altimeter Data Sets
    ———————————————————————————————————– Extraction of Mercury’s tidal signal and libration amplitude from synthetic laser altimeter data sets Von der Fakultät für Bauingenieurwesen und Geodäsie der Gottfried Wilhelm Leibniz Universität Hannover zur Erlangung des Grades DOKTOR - INGENIEUR genehmigte Dissertation von Dipl.-Ing. Christian Koch HANNOVER 2009 ———————————————————————————————————– Diese Arbeit ist gleichzeitig veröffentlicht in: Wissenschaftliche Arbeiten der Fachrichtung Geodäsie und Geoinformatik der Leibniz Universität Hannver ISSN 0174-1454, Nr. 280, Hannover 2009 Referent: Prof. Dr.-Ing. habil. Jürgen Müller Korreferenten: Prof. Dr. rer.nat. Ulrich R. Christensen Prof. Dr.-Ing. habil. Christian Heipke Tag der mündlichen Prüfung: 25. Juni 2009 Summary Within the next decade, two space missions will investigate Mercury, the innermost planet of the solar system. NASA’s MESSENGER spacecraft is presently on its way to Mercury and will be inserted into orbit in 2011, while BepiColombo will be launched in 2014 to arrive at Mercury after a six-year-cruise in 2020. Both missions apply laser altimeters to map the global topography and to extract the tidal signal of Mercury’s surface which oc- curs due to solar gravitation. The purpose of this study is to investigate different analysis methods which allow to extract the tidal elevation, expressed by the dimensionless tidal Love number h2. The determination of the Love number h2 is one of the very few methods that allows to study the interior of a planet from orbiting spacecraft. Provided that Mer- cury has a liquid outer core, the tidal elevation amplitude is of order 1 m, corresponding to a Love number h 0.7 (Van Hoolst and Jacobs 2003), otherwise it is much smaller.
    [Show full text]