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Gravity Recovery and Interior Laboratory

Phase: Past

Launch Date: September 10, 2011

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GRAIL craft in tandem

GRAIL's Twin Spacecraft fly in Tandem Around the Moon (Artist's Concept)

The Gravity Recovery and Interior Laboratory (GRAIL) mission was competitively selected through the Discovery Program. GRAIL launched on a Delta II launch vehicle and will use high-quality gravity field mapping of the moon to determine the moon's interior structure.

GRAIL’s primary science objectives will be to determine the structure of the lunar interior, from crust to core and to advance understanding of the thermal evolution of the Moon. As a secondary objective, GRAIL will extend knowledge gained from the Moon to the other terrestrial planets.

Science investigations will include:
• Map the structure of the crust and lithosphere
• Understand the Moon’s asymmetric thermal evolution
• Determine the subsurface structure of impact basins and the origin of mascons
• Ascertain the temporal evolution of crustal brecciation and magmatism
• Constrain deep interior structure from tides
• Place limits on the size of a possible solid inner core

Maria Zuber of the Massachusetts Institute of Technology, Cambridge, Mass., is GRAIL's principal investigator. NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the project.