FILE - This undated artist file rendering provided by NASA on Dec. 21, 2011, shows the twin Grail spacecraft mapping the lunar gravity field. Launched from Cape Canaveral on Sept. 10, 2011, the spacecraft began collecting data in March, 2012. After nearly a year circling the moon, NASA's Ebb and Flow spacecraft will meet their demise when they are scheduled to crash - on purpose - into a lunar mountain Monday, Dec. 17, 2012, ending a successful mission. (AP Photo/NASA, Jet Propulsion Laboratory, File)
AP PROVIDES ACCESS TO THIS PUBLICLY DISTRIBUTED FILE HANDOUT PHOTO PROVIDED BY NASA/JPL.
FILE - This undated artist file rendering provided by NASA on Dec. 21, 2011, shows the twin Grail spacecraft mapping the lunar gravity field. Launched from Cape Canaveral on Sept. 10, 2011, the spacecraft began collecting data in March, 2012. After nearly a year circling the moon, NASA's Ebb and Flow spacecraft will meet their demise when they are scheduled to crash - on purpose - into a lunar mountain Monday, Dec. 17, 2012, ending a successful mission. (AP Photo/NASA, Jet Propulsion Laboratory, File)
