NASA’s GRAIL Mission Solves Mystery of Moon’s Surface Gravity

[Amaterasu]

For what these data are worth:

http://www.zerognews.com/2013/06/02/nasas-grail-mission-solves-mystery-of-moons-surface-gravity/

PASADENA, CA – NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission has uncovered the origin of massive invisible regions that make the moon's gravity uneven, a phenomenon that affects the operations of lunar-orbiting spacecraft. Because of GRAIL's findings, spacecraft on missions to other celestial bodies can navigate with greater precision in the future.

GRAIL's twin spacecraft studied the internal structure and composition of the moon in unprecedented detail for nine months. They pinpointed the locations of large, dense regions called mass concentrations, or mascons, which are characterized by strong gravitational pull. Mascons lurk beneath the lunar surface and cannot be seen by normal optical cameras.

GRAIL scientists found the mascons by combining the gravity data from GRAIL with sophisticated computer models of large asteroid impacts and known detail about the geologic evolution of the impact craters. The findings are published in the May 30 edition of the journal Science.

"GRAIL data confirm that lunar mascons were generated when large asteroids or comets impacted the ancient moon, when its interior was much hotter than it is now," said Jay Melosh, a GRAIL co-investigator at Purdue University in West Lafayette, Ind., and lead author of the paper. "We believe the data from GRAIL show how the moon's light crust and dense mantle combined with the shock of a large impact to create the distinctive pattern of density anomalies that we recognize as mascons."

More at link.