As if scanning the moon's surface for impact blemishes were not enough, NASA now plans to visualize its internal imperfections to solve longstanding mysteries about the moon's insides. NASA said this week that it selected the Gravity Recovery and Interior Laboratory (GRAIL) mission from two dozen proposals. GRAIL's twin spacecraft are slated to launch around Sept. 6, 2011 and, after a few weeks of settling into orbit, map the lunar gravity field for 90 days. Scientists hope to use the data to pick apart its insides from crust to core, much like a medical X-ray that shows the insides of a person. "We're looking forward to the data," Michael New, GRAIL's lead project scientist, told SPACE.com. "It's really going to open up new understanding of the particular history and internal structure of the moon." Crust to core NASA previously launched a mission to map Earth's gravitational fields, called GRACE—the Gravity Recovery and Climate Experiment. Over the years, it measured minute differences in gravitational pull at different points around our planet, revealing glacial melt, migrating magma and tectonic plate movement, among other curiosities. Similarly, GRAIL will measure gravity at different points around the moon, which should reveal any gravity differences as slight as 1 million times weaker than the Earth's overall gravity.
New said the data will be about 1,000 times better than any other measurements of lunar gravity, explaining that such data can be processed to peer beneath the moon's surface and locate any significant structures related to early lunar history.
