GRGM900C: A degree 900 lunar gravity model from GRAIL primary and extended mission data

Frank G Lemoine; Sander Goossens; Terence J Sabaka; Joseph B Nicholas; Erwan Mazarico; David D Rowlands; Bryant D Loomis; Douglas S Chinn; Gregory A Neumann; David E Smith; Maria T Zuber

doi:10.1002/2014GL060027

GRGM900C: A degree 900 lunar gravity model from GRAIL primary and extended mission data

Geophys Res Lett. 2014 May 28;41(10):3382-3389. doi: 10.1002/2014GL060027. Epub 2014 May 29.

Authors

Affiliations

¹ NASA Goddard Space Flight Center Greenbelt, Maryland, USA.
² NASA Goddard Space Flight Center Greenbelt, Maryland, USA ; CRESST, University of Maryland, Baltimore County Baltimore, Maryland, USA.
³ NASA Goddard Space Flight Center Greenbelt, Maryland, USA ; Emergent Space Technologies Greenbelt, Maryland, USA.
⁴ NASA Goddard Space Flight Center Greenbelt, Maryland, USA ; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology Cambridge, Massachusetts, USA.
⁵ NASA Goddard Space Flight Center Greenbelt, Maryland, USA ; Stinger Ghaffarian Technologies Inc. Greenbelt, Maryland, USA.
⁶ Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology Cambridge, Massachusetts, USA.

Abstract

We have derived a gravity field solution in spherical harmonics to degree and order 900, GRGM900C, from the tracking data of the Gravity Recovery and Interior Laboratory (GRAIL) Primary (1 March to 29 May 2012) and Extended Missions (30 August to 14 December 2012). A power law constraint of 3.6 ×10^-4/ℓ² was applied only for degree ℓ greater than 600. The model produces global correlations of gravity, and gravity predicted from lunar topography of ≥ 0.98 through degree 638. The model's degree strength varies from a minimum of 575-675 over the central nearside and farside to 900 over the polar regions. The model fits the Extended Mission Ka-Band Range Rate data through 17 November 2012 at 0.13 μm/s RMS, whereas the last month of Ka-Band Range-Rate data obtained from altitudes of 2-10 km fit at 0.98 μm/s RMS, indicating that there is still signal inherent in the tracking data beyond degree 900.