First independent Graz Lunar Gravity Model derived from GRAIL

Harald Wirnsberger, Sandro Krauß, Torsten Mayer-Gürr

Research output: Contribution to journalArticlepeer-review

Abstract

The twin satellite mission Gravity Recovery and Interior Laboratory (GRAIL) aims to recover the lunar gravity field by means of Ka-band ranging observations. In order to exploit the potential of the inter-satellite range variations, absolute position information of the two probes is required. Hitherto, the Graz lunar gravity field models (GrazLGM) relied on the official science orbit products provided by NASA. In this contribution, we present for the first time a completely independent Graz Lunar Gravity Model based on Primary Mission data. The models are resolved up to spherical harmonic degree and order 420. The orbits of the two probes are determined using variational equations following a batch least squares differential adjustment process implemented in the in-house developed software package ORCA (Orbit Re-Construction Application). These orbits are based on S-band radiometric tracking data collected by the Deep Space Network (DSN) and are used for the independent GRAIL gravity field recovery. To reveal a highly accurate lunar gravity field, an integral equation approach using short orbital arcs is adopted to process the Ka-band data, where no regularization or Kaula constraint is applied. The correlation of gravity with lunar topography as well as the Bouguer spectrum of our solutions is comparable to the models officially released by the GRAIL Science Team.
Original languageEnglish
Pages (from-to)324-336
JournalIcarus
DOIs
Publication statusPublished - 24 Aug 2018

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