Data Set Information
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| DATA_SET_NAME |
MRO RADIO SCIENCE DERIVED GRAVITY SCIENCE DATA PRODUCTS V1.0
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| DATA_SET_ID |
MRO-M-RSS-5-SDP-V1.0
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| NSSDC_DATA_SET_ID |
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| DATA_SET_TERSE_DESCRIPTION |
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| DATA_SET_DESCRIPTION |
Data Set Overview : The Mars Reconnaisance Orbiter (MRO) Gravity Archive Data Collection of Science Data Products (SDP) includes data products generated from radio occultation, gravity, and surface reflection investigations conducted by members of the MRO Gravity Team. Gravity SDPs include spherical harmonic models, maps or images of those models, and possibly line-of-sight acceleration profiles. Groups at the Goddard Space Flight Center (GSFC) under the direction of David Smith and at JPL under the direction of William Sjogren produced spherical harmonic models, maps, and images. The models are derived from a mix of data, including data from the missions of Mars Global Surveyor, Mars Odyssey, and Mars Reconnaissance Orbiter. These spacecraft have different orbit characteristics (primarily mean periapse and apoapsis altitudes for these near-polar and near circular orbits) which determine their sensitivity to the Mars gravity field. The Mars Reconnaissance Orbiter was in an orbit with a periapse near 250 km and an apoapsis near 320 km. As with the other Mars mapping missions (Mars Global Surveyor and Mars Odyssey), periapsis was frozen over the South Pole. Aerobraking data are not including in these solutions since (a) There is usually no radio tracking of the spacecraft available through periapsis, and (b) the frequent firing of thrusters during the periapsis passes and the strong drag signal will mask any signal from Mars gravity. The Mars Global Surveyor spacecraft remained operational from 1997 through 2005, spending the bulk of its time (after March 1999) in a low-altitude mapping orbit whose mean periapsis was 370 km and mean apoapsis was 420 to 430 km. The Mars Odyssey spacecraft was in a similar orbit albeit with slightly higher altitude. An approximately two week segment of Mars Odyssey tracking data was obtained from the 'transition orbit', an orbit intermediate in orbit altitude mean the aerobraking altitude and the mapping orbit altitude, with a periapsis near 200 km and an apoapsis near 500 km. Parameters : Spherical harmonic models are tables of coefficients GM, Cmn, and Smn -- as in equation (1) of [TYLERETAL1992]. These can be used to represent gravitational potential of Mars, for example. Both ASCII (data type SHA) and binary (data type SHB) formats are defined, with the latter being preferred for large files which also include covariance terms. Each file contains up to four tables: a header table containing general parameters for the model (gravitational constant, its uncertainty, degree and order of the field, normalization state, reference longitude, and reference latitude); a names table, giving the order in which coefficients appear; a coefficients table (degree m, order n, coefficients Cmn and Smn, and their uncertainties); and a covariances table giving the covariances of CijCmn, SijSmn, CijSmn, and SijCmn. Radio Science Digital Map files are image representations of gravity and other parameters. Free air gravity, geoid, Bouguer anomaly, isostatic anomaly, and topographic values may be displayed using this data type. Data are formatted as PDS image objects. The Line-of-Sight Acceleration Profile Data Record is a pair of PDS tables. The first table contains header information such as time and observing geometry, parameters used in deriving acceleration from radio tracking measurements, and first-order Keplerian orbit elements. The second table gives spacecraft acceleration versus time. Also included at each time is the spacecraft position in planetocentric coordinates. Processing : Spherical harmonic models, maps, and line-of-sight acceleration profiles are derived from raw radio tracking data in several steps. The tracking data are processed in large orbit determination programs that integrate the equations of motion (DPODP at JPL [MOYER1971], and GEODYN at NASA GSFC [PAVLISETAL2007]), and model mathematically the radio science observables (ramped Doppler and range data). The observations are related to the geophysical parameters through the numerical integration and the detailed mathematical modeling of the radio science observables, and of all forces acting on the spacecraft trajectory, including planetary and third body gravity, solar radiation pressure, planetary radiation pressure, atmospheric drag, solid body tides, and relativity. The gravity field coefficients are obtained by accumulating normal equations from often hundreds of data arcs, and solving these systems of linear equations with thousands of unknowns. The unknowns include arc parameters, particular to one data arc (such as the spacecraft state, radiation pressure scale factors, atmospheric drag scale factors, etc.) and common parameters (such as the gravity coefficients, the planetary gravitational constant or GM, the Phobos and Deimos gravitational constants, and the Mars K2 Love number). Radio tracking data are processed in arcs delimited by propulsive maneuvers, occultations, etc. The Mars orbiting spacecraft perform regular angular momentum desaturation (AMD) maneuvers to remove the angular momentum that has accumulated in the spacecraft momentum wheels. On MRO, these AMD maneuvers occur usually every 2-3 days, and arcs may be delimited by these maneuvers. AMD maneuvers on MGS and Mars Odyssey were much more frequent up to several times per day in some cases. In those circumstances the AMD's must be modeled in the orbit determination solution and solved for empirically along with the other orbital arc parameters. The times of the AMD's are specified in the small forces files (SFF) that are part of the MRO raw data archive. Maps of free air gravity and other quantities are generated from the spherical harmonic model(s) evaluated at regular grid points. Line-of-sight acceleration profiles are derived from single arcs of radio tracking data. Doppler residuals with respect to a specific spherical harmonic model are spline-fitted; the splines are then differentiated analytically to obtain accelerations. Useful references which describe the procedures applied in general to processing Mars orbiter tracking data include [YUANETAL2001], [LEMOINEETAL2001], [KONOPLIVETAL2006]. [THORNTON&BORDER2003] is a general reference for Orbit Determination. Data : Data are available online through the Planetary Data System (http://pds.nasa.gov). A volume of reduced data was prepared for the MRO primary mission and it is expected that a volume will be prepared for the extended mission. ASCII spherical harmonic models are stored in the SHA directory with file names of the form GTsss_nnnnvv_SHA.TAB where 'G' denotes the generating institution 'J' for the Jet Propulsion Laboratory 'G' for Goddard Space Flight Center 'C' for Centre National d'Etudes Spatiales 'M' for Massachusetts Institute of Technology 'T' indicates the type of data represented 'G' for gravity field 'T' for topography 'M' for magnetic field 'sss' is a 3-character modifier specified by the data producer. This modifier is used to indicate the source spacecraft or project, such as MRO for the Mars Reconnaisance Orbiter. '_' the underscore character is used to delimit modifiers in the file name for clarity. 'nnnnvv' is a 4- to 6-character modifier specified by the data producer. Among other things, this modifier may be used to indicate the target body, whether the SHADR contains primary data values as specified by 'T' or uncertainties/errors, and/or the version number. For MRO, this modifier indicates the degree and order of the solution for the gravity field, topography or magnetic field. '_' the underscore character is used to delimit information in the file name for clarity. 'SHA' denotes that this is an ASCII file of Spherical Harmonic coefficients '.TAB' indicates the data is stored in tabular form. Each SHADR file is accompanied by a detached PDS label; that label is a file in its own right, having the name GTsss_nnnnvv_SHA.LBL. Binary spherical harmonic models are stored in the SHB directory with file names of the form GTsss_nnnnvv_SHB.DAT where 'G' denotes the generating institution 'J' for the Jet Propulsion Laboratory 'G' or Goddard Space Flight Center 'C' or Centre National d'Etudes Spatiales 'M' for Massachusetts Institute of Technology 'T' indicates the type of data represented 'G' for gravity field 'T' for topography 'M' for magnetic field 'sss' is a 3-character modifier specified by the data producer. This modifier is used to indicate the source spacecraft or Project, such as MRO for the Mars Reconnaissance Orbiter. '_' the underscore character is used to delimit modifiers in the file name for clarity. 'nnnnvv' is a 4- to 6-character modifier specified by the data producer. Among other things, this modifier may be used to indicate the target body, whether the SHBDR contains primary data values as specified by 'T' or uncertainties/errors, and/or the version number. For MRO, this modifier indicates the degree and order of the solution for the gravity field, topography or magnetic field. '_' the underscore character is used to delimit modifiers in the file name for clarity. 'SHB' denotes that this is a Binary file of Spherical Harmonic coefficients and error covariance information '.DAT' indicates the data is stored in binary format. Each SHBDR file is accompanied by a detached PDS label; that label is a file in its own right, having the name GTsss_nnnnvv_SHB.LBL. Radio Science Digital Map products are stored in the RADMAP directory with file names of the form GTsss_ffff_nnnn_cccc.IMG where 'G' denotes the generating institution 'A' for Arizona State University 'J' for the Jet Propulsion Laboratory 'G' for Goddard Space Flight Center 'C' for Centre National d'Etudes Spatiales 'S' for Stanford University 'T' indicates the type of mission data represented 'G' for gravity field 'T' for topography 'M' for magnetic field 'sss' is a 3-character modifier specified by the data producer. This modifier is used to indicate the source spacecraft or project, such as MRO for the Mars Reconnaisance Orbiter. '_' the underscore character is used to delimit information in the file name for clarity. 'ffff' is a 4-character modifier specified by the data producer to indicate the degree and order of the solution for the gravity field, topography or magnetic field. '_' the underscore character is used to delimit information in the file name for clarity. 'nnnn' is a 4- to 8-character modifier indicating the type of data represented 'ANOM' for free air gravity anomalies 'ANOMERR' for free air gravity anomaly errors (1) 'GEOID' for geoid 'GEOIDERR' for geoid errors (1) 'BOUG' for Bouguer anomaly 'ISOS' for isostatic anomaly 'TOPO' for topography 'MAGF' for magnetic field (1) Geoid and gravity anomaly errors are computed from a mapping of the error covariance matrix of the gravity field solution. '_' the underscore character is used to delimit information in the file name for clarity. 'cccc' is a 4-character modifier specified by the data producer to indicate the degree and order to which the potential solution (gravity, topography or magnetic field) has been evaluated. In the case of the error maps for the gravity anomalies or geoid error, this field indicates to which maximum degree and order the error covariance was used to propagate the spatial errors '.IMG' indicates the data is stored as an image. Each RSDMAP file is accompanied by a detached PDS label; that label is a file in its own right with name GTsss_ffff_nnnn_cccc.LBL Coordinate System : MRO Gravity SDP files use a Mars centered body-fixed coordinate system with positive east longitude. Gravity models are defined in the Mars coordinate system defined by [KONOPLIVETAL2006]. This coordinate system supersedes the IAU 1991 and IAU 2000 coordinate systems used for most previous Mars gravity models. See labels of specific gravity products for details. Software : None. Media/Format : This data set is stored online at the Planetary Data System (http://pds.nasa.gov/) and may be downloaded using a web browser or FTP software. A copy may be requested on physical media if downloading is not possible. The Planetary Data System maintains backup copies of this data set on various media.
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| DATA_SET_RELEASE_DATE |
2010-10-01T00:00:00.000Z
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| START_TIME |
2006-08-30T06:00:00.000Z
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| STOP_TIME |
2008-10-31T04:00:00.000Z
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| MISSION_NAME |
MARS RECONNAISSANCE ORBITER
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| MISSION_START_DATE |
2005-08-12T12:00:00.000Z
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| MISSION_STOP_DATE |
N/A (ongoing)
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| TARGET_NAME |
MARS
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| TARGET_TYPE |
PLANET
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| INSTRUMENT_HOST_ID |
MRO
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| INSTRUMENT_NAME |
RADIO SCIENCE SUBSYSTEM
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| INSTRUMENT_ID |
RSS
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| INSTRUMENT_TYPE |
RADIO SCIENCE
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| NODE_NAME |
Geosciences
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| ARCHIVE_STATUS |
ARCHIVED - ACCUMULATING
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| CONFIDENCE_LEVEL_NOTE |
Overview : Data in this archive have been reduced as part of mission data analysis activities of the MRO Gravity Team. Products of questionable validity have been flagged or omitted. Review : This archival data set was reviewed by the MRO Gravity Team prior to submission to the Planetary Data System (PDS). Data set design, documentation, and sample products have passed a PDS peer review. Prior to creation of the final version of the archival data set, key elements of the archive were distributed for preliminary review. These included electronic versions of example PDS labels, example data files, CATALOG files, and Software Interface Specifications. These materials were distributed to PDS personnel, the experiment investigator, and others, as appropriate. Data Coverage and Quality : This volume contains gravity models and maps generated from Viking 1 Lander, Pathfinder, MGS, Odyssey, and MRO data collected through the end of October 2008. The Viking and Mariner 9 orbiter data were not included in this delivery as this data did not seem to any more information for the gravity field. The MRO data included tracking results from Transition Orbit and Mapping Orbit phases. All useful MGS tracking data collected prior to the loss of the spacecraft in Nov. 2006 was used. Odyssey data included tracking data from Transition Orbit and Mapping Orbit phases. JGMRO_095A_SHA.TAB is an ASCII file of coefficients and related data for a 95th degree and order Mars static gravity field produced at the Jet Propulsion Laboratory. The model used is described in the file's detached label. JGMRO_095A_SHB.DAT is a binary file of covariances and related data for a 95th degree and order Mars static gravity field produced at the Jet Propulsion Laboratory. The model used is described in the file's detached label. JGMRO_O95A_GEOIDERR_085.IMG is a digital map of the Mars geoid formal uncertainty derived from the covariance matrix for the spherical harmonic coefficients of the JPL MRO95A Mars gravity field. The JGMRO_O95A_GEOIDERR_085 geoid error is computed from a truncated MRO95A covariance (from degree 2 up to degree 85). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_O95A_GEOID_085.IMG is a digital map of the Mars geoid derived from the JPL MRO95A spherical harmonic model of the Mars gravity field. Each point is the Mars geoid height in meters above a reference ellipsoid (semi-major-axis : 3397.0 km, GM : 42828.35796 km**3/s**2, flattening : 5.079304192e-3, and rotation rate : 7.088218081e-5 rad/s). The JGMRO_095A_GEOID85 geoid is computed from a truncated MRO95A solution (from degree 2 up to degree 85). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_095A_ANOM_085.IMG is a digital map of the gravity anomaly derived from the JPL MRO95A model of the Mars gravity field. Each point gives the Mars gravity anomaly in milligals, which is the difference of the model gravity on the geoid from the normal gravity on a reference ellipsoid with semi-major-axis : 3397.0 km, GM : 42828.35796 km**3/s**2, flattening : 5.079304192e-3, and rotation rate : 7.088218081e-5 rad/s. The JGMRO_095A_ANOM85 gravity anomaly is computed from a truncated MRO95A solution (from degree 2 up to degree 85). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_095A_ANOMERR_085.IMG is a digital map of the Mars gravity anomaly formal uncertainty derived from the covariance matrix for the spherical harmonic coefficients of the JPL MRO95A Mars gravity field. Each point gives the Mars gravity anomaly error in milligals, which is the error of the model gravity on the geoid defined by the reference ellipsoid with semi-major-axis : 3397.0 km, GM : 42828.35796 km**3/s**2, flattening : 5.079304192e-3, and rotation rate : 7.088218081e-5 rad/s. The JGMRO_095A_ANOM85_ERR gravity anomaly is computed from a truncated MRO95A solution (from degree 2 up to degree 85). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_110B2_GEOIDERR_095.IMG is a digital map of the Mars geoid formal uncertainty derived from the covariance matrix for the spherical harmonic coefficients of the JPL MR110B2 Mars gravity field. The JGMRO_110B2_GEOIDERR_095 geoid error is computed from a truncated MR110B2 covariance (from degree 2 up to degree 95). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_110B2_GEOID_095.IMG is a digital map of the Mars geoid derived from the JPL MR110B2 spherical harmonic model of the Mars gravity field. Each point is the Mars geoid height in meters above a reference ellipsoid (semi-major-axis : 3397.0 km, GM : 42828.35796 km**3/s**2, flattening : 5.079304192e-3, and rotation rate : 7.088218081e-5 rad/s). The JGMRO_110B2_GEOID_095 geoid is computed from a truncated MR110B2 solution (from degree 2 up to degree 95). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_110B_GEOIDERR_095.IMG is a digital map of the Mars geoid formal uncertainty derived from the covariance matrix for the spherical harmonic coefficients of the JPL MR110B Mars gravity field. The JGMRO_110B_GEOIDERR_095 geoid error is computed from a truncated MR110B covariance (from degree 2 up to degree 95). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_110B_GEOID_095.IMG is a digital map of the Mars geoid derived from the JPL MR110B spherical harmonic model of the Mars gravity field. Each point is the Mars geoid height in meters above a reference ellipsoid (semi-major-axis : 3397.0 km, GM : 42828.35796 km**3/s**2, flattening : 5.079304192e-3, and rotation rate : 7.088218081e-5 rad/s). The JGMRO_110B_GEOID_095 geoid is computed from a truncated MR110B solution (from degree 2 up to degree 95). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_110B2_ANOM_095.IMG is a digital map of the gravity anomaly derived from the JPL MRO110B2 model of the Mars gravity field. Each point gives the Mars gravity anomaly in milligals, which is the difference of the model gravity on the geoid from the normal gravity on a reference ellipsoid with semi-major-axis : 3397.0 km, GM : 42828.35796 km**3/s**2, flattening : 5.079304192e-3, and rotation rate : 7.088218081e-5 rad/s. The JGMRO_110B2_ANOM_095 gravity anomaly is computed from a truncated MRO110B2 solution (from degree 2 up to degree 95). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_110B2_ANOMERR_095.IMG is a digital map of the Mars gravity anomaly formal uncertainty derived from the covariance matrix for the spherical harmonic coefficients of the JPL MRO110B2 Mars gravity field. Each point gives the Mars gravity anomaly error in milligals, which is the error of the model gravity on the geoid defined by the reference ellipsoid with semi-major-axis : 3397.0 km, GM : 42828.35796 km**3/s**2, flattening : 5.079304192e-3, and rotation rate : 7.088218081e-5 rad/s. The JGMRO_110B2_ANOMERR_095 gravity anomaly is computed from a truncated MRO110B2 solution (from degree 2 up to degree 95). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_110B_ANOM_095.IMG is a digital map of the gravity anomaly derived from the JPL MRO110B model of the Mars gravity field. Each point gives the Mars gravity anomaly in milligals, which is the difference of the model gravity on the geoid from the normal gravity on a reference ellipsoid with semi-major-axis : 3397.0 km, GM : 42828.35796 km**3/s**2, flattening : 5.079304192e-3, and rotation rate : 7.088218081e-5 rad/s. The JGMRO_110B_ANOM_095 gravity anomaly is computed from a truncated MRO110B solution (from degree 2 up to degree 95). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. JGMRO_110B_ANOMERR_095.IMG is a digital map of the Mars gravity anomaly formal uncertainty derived from the covariance matrix for the spherical harmonic coefficients of the JPL MRO110B Mars gravity field. Each point gives the Mars gravity anomaly error in milligals, which is the error of the model gravity on the geoid defined by the reference ellipsoid with semi-major-axis : 3397.0 km, GM : 42828.35796 km**3/s**2, flattening : 5.079304192e-3, and rotation rate : 7.088218081e-5 rad/s. The JGMRO_110B_ANOMERR_095 gravity anomaly is computed from a truncated MRO110B solution (from degree 2 up to degree 95). The map is produced by Alex Konopliv at JPL for the MRO Gravity Science Team. Limitations : The limitations in this data set follow from the quality of the execution, which is described above under Data Coverage and Quality.
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| CITATION_DESCRIPTION |
Lemoine, F.G, A. Konopliv, M. Zuber, MRO Derived Gravity Science Data Products, MRO-M-RSS-5-SDP-V1.0, NASA Planetary Data System, 2008.
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| ABSTRACT_TEXT |
This data set contains archival results from gravity investigations conducted during the Mars Reconnaissance Orbiter (MRO) mission. Radio measurements were made using the MRO spacecraft and Earth-based stations of the NASA Deep Space Network (DSN). The data set includes high-resolution spherical harmonic models of Mars' gravity field generated by groups at the Jet Propulsion Laboratory and Goddard Space Flight Center, covariance matrices for some models, and maps for some models; these results were derived from raw radio tracking data. Updates to the archive may include derived line-of-sight acceleration profile.
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| PRODUCER_FULL_NAME |
FRANK G. LEMOINE
MARIA T. ZUBER
A. KONOPLIV
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| SEARCH/ACCESS DATA |
Geosciences Web Service
Mars Orbital Data Explorer
Geosciences FTP Resource
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