urn:nasa:pds:mgs-rss:data-sha:ggm0964b 1.0 1.22.0.0 Product_Observational 2025 MGS RSS This file contains coefficients and related data for the spherical harmonic model MGM0964C20 of the Mars gravity field. Input data are from radio tracking of the Mars Global Surveyor spacecraft. The coordinate system is IAU 1991 The data cover 1997-10-13T00:00:00Z to 1999-03-27T23:59:59Z. Frank Lemoine 1 Goddard Space Flight Center https://ror.org/0171mag52 David Smith 2 Goddard Space Flight Center https://ror.org/0171mag52 2025-02-11 1.0 This product, GGM0964B.SHA, was originally released as part of the PDS3 MGS-M-RSS-5-SDP-V1.0 data set. The metadata have been migrated to PDS4. The data themselves are unchanged. 1997-10-13T00:00:00Z 1999-03-27T23:59:59Z Science Derived Mars Global Surveyor Spherical Harmonic Model ASCII Data Mars Global Surveyor Mission urn:nasa:pds:context:investigation:mission.mars_global_surveyor data_to_investigation Mars Global Surveyor Host urn:nasa:pds:context:instrument_host:spacecraft.mgs is_instrument_host Radio Science Subsystem (RSS) Instrument urn:nasa:pds:context:instrument:mgs.rss is_instrument Mars Planet urn:nasa:pds:context:target:planet.mars data_to_target urn:nasa:pds:mgs-rss:data-maps:ggm0964e::1.0 data_to_derived_product 10.1007/BF00051818 Davies, M. E., V. K. Abalakin, A. Brahic, M. Bursa, B.H. Chovitz, J. H. Lieske, P. K. Seidelmann, A. T. Sinclair, Y. S. Tjuflin, Report of the IAU/IAG/COSPAR Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Satellites: 1991, Celestial Mechanics and Dynamical Astronomy, 53, 377-397, 1992. Coordinate System is IAU 1991. Kaula, W.M., Theory of Satellite Geodesy, Blaisdell, Waltham, MA, 1966. The gravity model was derived using a Kaula type constraint: sqrt(2)*13*10**(-5)/L**2 where L is the spherical harmonic degree. Without this constraint, the high degree terms develop excessive power. Lemoine, F. G., D. D. Rowlands, G. A. Neumann, D. E. Smith, D. E. Pavlis, D. S. Chinn, S. B. Luthcke, Precise orbit determination for Mars Global Surveyor during hiatus and SPO, Spaceflight Mechanics 1999 R. H. Bishop, et al.AAS Paper 99-147, 649-666Am. Astron. Soc., Washington, D.C., 1999a. Performance of the gravity model can be evaluated by computing the orbit position discrepancy between overlapping arcs. The set of overlapping arcs included twelve overlaps of thirteen 30-hour arcs in February 1999 (overlap length was six hours) and six overlaps of five- to six-day arcs in March. Average RMS Overlaps for Gravity Models MGM0964C18 and MGM0964C20 Model Radial Cross-Track Along-Track Total (m) (m) (m) (m) ------------- ------ ----------- ----------- ------ MGM0964C18 5.52 21.32 39.33 45.54 MGM0964C20 5.23 8.59 24.76 27.12 MGS-M-RSS-5-SDP-V1.0:GGM0964B.SHA:GGM0964B.SHA data_to_derived_source_product 10.17189/1519757 PDS Planetary Plasma Interactions Node This is the first version converted to PDS4. The DOI references the source PDS3 data set. GGM0964B.SHA 2001-03-21T09:45:35 311710 655cb1e5f169fa26130e00ce3f6e5bd0 The MGM0964C20 model has been superseded by model GMM2B, also included in this archival volume. But MGM0964C20 was the reference gravity field for a number of other data sets, including some from the Mars Orbiting Laser Altimeter (MOLA). On that basis, it was deemed important to include it in the archive. MGS Spherical Harmonic ASCII MGM0964C20 Model Header 1997-10-13 - 1999-03-27 0 1 Carriage-Return Line-Feed 8 0 244 Reference Radius 1 1 ASCII_Real 23 The assumed reference radius of the spherical planet. Constant 2 25 ASCII_Real 23 For a gravity field model the assumed gravitational constant GM in km cubed per seconds squared for the planet. For a topography model, set to 1. Uncertainty in Constant 3 49 ASCII_Real 23 For a gravity field model the uncertainty in the gravitational constant GM in km cubed per seconds squared for the planet (or, set to 0 if not known). For a topography model, set to 0. Degree of Field 4 73 ASCII_Integer 5 deg of the model field. Order of Field 5 79 ASCII_Integer 5 Order of the model field. Normalization State 6 85 ASCII_Integer 5 The normalization indicator. For gravity field: 0 coefficients are unnormalized 1 coefficients are normalized 2 other. Reference Longitude 7 91 ASCII_Real 23 deg The reference longitude for the spherical harmonic expansion; normally 0. Reference Latitude 8 115 ASCII_Real 23 deg The reference latitude for the spherical harmonic expansion; normally 0. MGS Spherical Harmonic ASCII MGM0964C20 Model Coefficients Table 1997-10-13 - 1999-03-27 244 PDS DSV 1 The model was constructed from 350,195 observations, summarized in the table below. MGS data are limited to tracking from the Aerobraking Hiatus and Science Phasing Orbit (SPO) subphases of the Orbit Insertion phase of the mission and to February and March 1999 after the orbit was circularized. Time Periods Observations ----------------------- ------------ Hiatus and SPO 257165 February and March 1999 93030 ----------------------- ------------ Total 350195 2553 Carriage-Return Line-Feed Comma 6 0 Coefficient Degree 1 ASCII_Integer 5 %5d The degree index m of the C and S coefficients in this record. Coefficient Order 2 ASCII_Integer 5 %5d The order index n of the C and S coefficients in this record. C 3 ASCII_Real 23 %23.16e The coefficient Cmn for this spherical harmonic model. S 4 ASCII_Real 23 %23.16e The coefficient Smn for this spherical harmonic model. C Uncertainty 5 ASCII_Real 23 %23.16e The uncertainty in the coefficient Cmn for this spherical harmonic model. S Uncertainty 6 ASCII_Real 23 %23.16e The uncertainty in the coefficient Smn for this spherical harmonic model.