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Mercury's Global Topography from Radar Ranging DataWhen Mercury's radius is expanded in Legendre functions to the second degree and order, the systematic error in radar ranging data is reduced substantially. Previously, data spanning an observing interval from 1966 to 1990 were used to infer an equatorial ellipticity (a - b)/a = (540 +/- 54) X 10(exp -6) and a center-of-figure minus center-of-mass offset of (640 +/- 78) m. The magnitude of this equatorial center of figure offset implies an excess crustal thickness of 12 km or less, comparable to the Moon's excess. By comparing the equatorial ellipticity with the Mariner 10 gravity field, and assuming Airy isostatic compensation, bounds on crustal thickness can be derived. Mercury's crustal thickness is in the range from 100 to 300 km. The Mercury radar ranging observing interval has been extended from 1966 to the present. In addition, improvements in data reduction techniques have resulted in a set of Mercury ranging data less affected by systematic error, in particular the biases introduced by local topographic variations. We use this new set of reduced ranging data to improve Mercury's global topography and center-of-figure minus center-of-mass offset. New results on crustal thickness are derived, and prospects for further improvement with Mercury Orbiter data are discussed.
Document ID
20010124827
Acquisition Source
Jet Propulsion Laboratory
Document Type
Conference Paper
Authors
Anderson, J. D.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Schubert, G.
(California Univ. Los Angeles, CA United States)
Asmar, S. W.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Jurgens, R. F.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Lau, E. L.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Moore, W. B.
(California Univ. Los Angeles, CA United States)
Slade, M. A., III
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Standish, E. M., Jr.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA United States)
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Publication Information
Publication: Mercury: Space Environment, and Surface and Interior
Subject Category
Lunar And Planetary Science And Exploration
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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