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High‐resolution lunar gravity fields from the GRAIL Primary and Extended Missions

2014; American Geophysical Union; Volume: 41; Issue: 5 Linguagem: Inglês

10.1002/2013gl059066

1944-8007

A. S. Konopliv, Ryan S. Park, Dah‐Ning Yuan, S. W. Asmar, M. M. Watkins, J. G. Williams, Eugene G. Fahnestock, Gerhard Kruizinga, Meegyeong Paik, Dmitry Strekalov, Nate Harvey, David E. Smith, M. T. Zuber,

Astro and Planetary Science

Abstract The resolution and accuracy of the lunar spherical harmonic gravity field have been dramatically improved as a result of the Gravity Recovery and Interior Laboratory (GRAIL) mission. From the Primary Mission, previous harmonic gravity fields resulted in an average n = 420 surface resolution and a Bouguer spectrum to n = 330. The GRAIL Extended Mission improves the resolution due to a lower average 23 km altitude orbit. As a result, new harmonic degree 900 gravity fields (GL0900C and GL0900D) show nearly a factor of 2 improvement with an average surface resolution n = 870 and the Bouguer spectrum extended to n = 550. Since the minimum spacecraft altitude varies spatially between 3 km and 23 km, the surface resolution is variable from near n = 680 for the central farside to near n = 900 for the polar regions. These gravity fields with 0.8 million parameters are by far the highest‐degree fields of any planet ever estimated with a fully dynamic least squares technique using spacecraft tracking data.