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The Lunar Geophysical Network Mission
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  • Clive Neal,
  • Renee Weber,
  • William Banerdt,
  • Caroline Beghein,
  • Peter Chi,
  • Douglas Currie,
  • Simone Dell'Agnello,
  • Raphael Garcia,
  • Ian Garrick-Bethell,
  • Robert Grimm,
  • Matthias Grott,
  • Heidi Fuqua Haviland,
  • Taichi Kawamura,
  • Sharon Kedar,
  • Philippe Lognonné,
  • Seiichi Nagihara,
  • Yosio Nakamura,
  • Ceri Nunn,
  • Lillian Ostrach,
  • Noah Petro,
  • Nicholas Schmerr,
  • Matthew Siegler,
  • Thomas Watters,
  • Mark Wieczorek,
  • Kris Zacny,
  • Mark Panning
Clive Neal
University of Notre Dame

Corresponding Author:neal.1@nd.edu

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Renee Weber
NASA/NSSTC
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William Banerdt
Jet Propulsion Laboratory
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Caroline Beghein
UCLA - Earth and Space Sciences
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Peter Chi
University of California Los Angeles
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Douglas Currie
Organization Not Listed
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Simone Dell'Agnello
Laboratori Nazionali di Frascati dell’INFN
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Raphael Garcia
Institut Supérieur de l'Aéronautique et de l'Espace
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Ian Garrick-Bethell
University of California Santa Cruz
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Robert Grimm
Southwest Research Institute Boulder
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Matthias Grott
German Aerospace Ctr DLR
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Heidi Fuqua Haviland
UC Berkeley, Space Sciences Lab
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Taichi Kawamura
Université de Paris, Institut de physique du globe de Paris
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Sharon Kedar
JPL
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Philippe Lognonné
Université de Paris, Institut de physique du globe de Paris, CNRS
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Seiichi Nagihara
Texas Tech Univ
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Yosio Nakamura
Univ of Texas at Austin
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Ceri Nunn
University of Cambridge
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Lillian Ostrach
USGS Geological Survey
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Noah Petro
NASA GSFC
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Nicholas Schmerr
University of Maryland College Park
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Matthew Siegler
Planetary Science Institute Tucson
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Thomas Watters
Smithsonian Inst
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Mark Wieczorek
Observatoire de la Côte d'Azur - Laboratoire Lagrange
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Kris Zacny
Honeybee Robotics
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Mark Panning
Univ of FL-Geological Sciences
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Abstract

In 2007, the National Academies designated “understanding the structure & composition of the lunar interior” (to provide fundamental information on the evolution of a differentiated planetary body) as the second highest lunar science priority that needed to be addressed. Here we present the current status of the planned response of the Lunar Geophysical Network (LGN) team to the upcoming New Frontiers-5 AO. The Moon represents an end-member in the differentiation of rocky planetary bodies. Its small size (and heat budget) means that the early stages of differentiation have been frozen in time. But despite the success of the Apollo Lunar Surface Experiment Package (ALSEP), significant unresolved questions remain regarding the nature of the lunar interior and tectonic activity. General models of the processes that formed the present-day lunar interior are currently being challenged. While reinterpretation of the Apollo seismic data has led to the identification of a lunar core, it has also produced a thinning of the nearside lunar crust from 60-65 km in 1974 to 30-38 km today. With regard to the deep mantle, Apollo seismic data have been used to infer the presence of garnet below ~500 km, but the same data have also been used to identify Mg-rich olivine. A long-lived global lunar geophysical network (seismometer, heat flow probe, magnetometer, laser retro-reflector) is essential to defining the nature of the lunar interior and exploring the early stages of terrestrial planet evolution, add tremendous value to the GRAIL and SELENE gravity data, and allow other nodes to be added over time (ie, deliver the International Lunar Network). Identification of lateral and vertical heterogeneities, if present within the Moon, will yield important information about the early presence of a global lunar magma ocean (LMO) as well as exploring LMO cumulate overturn. LGN would also provide new constraints on seismicity, including shallow moonquakes (the largest type identified by ALSEP with magnitudes between 5-6) that have been linked to young thrust fault scarps, suggesting current tectonic activity. Advancing our understanding of the Moon’s interior is critical for addressing these and many other important lunar and Solar System science and exploration questions, including protection of astronauts from the strong shallow moonquakes.