elib
DLR-Header
DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Privacy Policy | Contact | Deutsch
Fontsize: [-] Text [+]

Mercury’s shape from radio occultations

Perry, Mark E. and Kahan, Daniel S. and Barnouin, Olivier S. and Ernst, Carolyn M. and Roberts, James H. and Neumann, Gregory A. and Mazarico, Erwan and Hauck, Steven A. and Solomon, Sean C. and Zuber, Maria T. and Smith, David E. and Phillips, Roger J. and Asmar, Sami W. and Gaskell, Robert W. and Oberst, Jürgen and Preusker, Frank (2012) Mercury’s shape from radio occultations. European Planetary Science Congress 2012, 23 – 28 September 2012, Madrid, Spain.

Full text not available from this repository.

Official URL: http://meetingorganizer.copernicus.org/EPSC2012/EPSC2012-743.pdf

Abstract

To support studies of Mercury’s internal structure, a MESSENGER mission goal is to measure the shape of the planet. Radio-frequency occultation observations contribute to this objective, particularly in most of the southern hemisphere where there are no altimeter data. We describe the techniques used to derive radius measurements from occultations and report results to date on the long-wavelength shape of Mercury. Before the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, Mercury’s shape was poorly constrained, primarily by Earth-based radar observations at low Mercury latitudes. During MESSENGER’s 12-month primary mission, the Mercury Laser Altimeter (MLA) acquired an extensive data set on the topography of Mercury’s northern hemisphere [1]. However, most of the southern hemisphere is beyond MLA range because the periapsis of MESSENGER’s highly inclined, eccentric orbit is at high northern latitudes. Along with limb measurements and global stereo mosaics, occultation-derived radius measurements are essential for understanding the shape of Mercury’s southern hemisphere. As viewed from Earth, the MESSENGER spacecraft passed behind Mercury every twelve hours for most of the primary mission. This geometry caused Mercury to occult the radio frequency (RF) transmissions, and we used an open-loop receiver to record RF power at the ingress and egress of each occultation. Incorporating the effects of diffraction, we extracted the time of occultation and used it to determine the RF path that grazed Mercury’s surface. The point on that RF path that is tangent to the surface defines a unique latitude, longitude, and radius. Since the highest point along the RF path provides the occultation edge, the radius measurements are biased high relative to the surrounding terrain. We corrected for this bias by evaluating topography local to the tangent point. Digital-elevation models (DEMs), derived from surface images acquired by MESSENGER’s Mercury Dual Imaging System (MDIS), contain the necessary topographic data. We compared northern-hemisphere occultation results to MLA data to

Item URL in elib:https://elib.dlr.de/80861/
Document Type:Conference or Workshop Item (UNSPECIFIED)
Title:Mercury’s shape from radio occultations
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Perry, Mark E. Planetary Exploration Group, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USAUNSPECIFIED
Kahan, Daniel S. Jet Propulsion Laboratory, Pasadena, CA 91109, USAUNSPECIFIED
Barnouin, Olivier S. Planetary Exploration Group, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USAUNSPECIFIED
Ernst, Carolyn M. Planetary Exploration Group, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USAUNSPECIFIED
Roberts, James H. Planetary Exploration Group, Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USAUNSPECIFIED
Neumann, Gregory A. NASA Goddard Space Flight Center, Greenbelt, MD 20771, USAUNSPECIFIED
Mazarico, Erwan NASA Goddard Space Flight Center, Greenbelt, MD 20771, USAUNSPECIFIED
Hauck, Steven A. Case Western Reserve University, Cleveland, OH 44106, USAUNSPECIFIED
Solomon, Sean C. Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015, USAUNSPECIFIED
Zuber, Maria T. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USAUNSPECIFIED
Smith, David E. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USAUNSPECIFIED
Phillips, Roger J. Planetary Science Directorate, Southwest Research Institute, Boulder, CO 80302, USAUNSPECIFIED
Asmar, Sami W. Jet Propulsion Laboratory, Pasadena, CA 91109, USAUNSPECIFIED
Gaskell, Robert W. Planetary Science Institute, Tucson, AZ 85712, USAUNSPECIFIED
Oberst, Jürgen Juergen.Oberst (at) dlr.deUNSPECIFIED
Preusker, Frank Frank.Preusker (at) dlr.deUNSPECIFIED
Date:September 2012
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Mercury, shape, radio occultations
Event Title:European Planetary Science Congress 2012
Event Location:Madrid, Spain
Event Type:international Conference
Event Dates:23 – 28 September 2012
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Vorhaben Exploration des Sonnensystems
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Planetary Geodesy
Deposited By: Beisembin, Bauyrzhan
Deposited On:24 Jan 2013 08:39
Last Modified:24 Jan 2013 08:39

Repository Staff Only: item control page

Browse
Search
Help & Contact
Information
electronic library is running on EPrints 3.3.12
Copyright © 2008-2017 German Aerospace Center (DLR). All rights reserved.