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The Gravity Field, Orientation, and Ephemeris of Mercury from MESSENGER Observations After Three Years in OrbitWe have analyzed three years of radio tracking data from the MESSENGER spacecraft in orbit around Mercury and determined the gravity field, planetary orientation, and ephemeris of the innermost planet. With improvements in spatial coverage, force modeling, and data weighting, we refined an earlier global gravity field both in quality and resolution, and we present here a spherical harmonic solution to degree and order 50. In this field, termed HgM005, uncertainties in low-degree coefficients are reduced by an order of magnitude relative to the earlier global field, and we obtained a preliminary value of the tidal Love number k(sub 2) of 0.451+/-0.014. We also estimated Mercury's pole position, and we obtained an obliquity value of 2.06 +/- 0.16 arcmin, in good agreement with analysis of Earth-based radar observations. From our updated rotation period (58.646146 +/- 0.000011 days) and Mercury ephemeris, we verified experimentally the planet's 3: 2 spin-orbit resonance to greater accuracy than previously possible. We present a detailed analysis of the HgM005 covariance matrix, and we describe some near-circular frozen orbits around Mercury that could be advantageous for future exploration.
Document ID
20150000346
Document Type
Preprint (Draft being sent to journal)
External Source(s)
Authors
Mazarico, Erwan M. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Genova, Antonio (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Goossens, Sander (Maryland Univ. Baltimore County Baltimore, MD, United States)
Lemoine, Gregory (NASA Goddard Space Flight Center Greenbelt, MD United States)
Neumann, Gregory A. (NASA Goddard Space Flight Center Greenbelt, MD United States)
Zuber, Maria T. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Smith, David E. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Solomon, Sean C. (Columbia Univ. Palisades, NY, United States)
Date Acquired
January 12, 2015
Publication Date
January 1, 2014
Subject Category
Lunar and Planetary Science and Exploration
Report/Patent Number
GSFC-E-DAA-TN18499
Funding Number(s)
CONTRACT_GRANT: NAS5-97271
CONTRACT_GRANT: NNG06EO90A
CONTRACT_GRANT: NASW-00002
CONTRACT_GRANT: NNX13AJ86G
CONTRACT_GRANT: NNX11AK30G
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
MESSENGER
Gravity Field
Ephemeris

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