Nasa launches gravity Moon probes

An unmanned Delta 2 rocket blasted off from Cape Canaveral Air Force on Saturday to send a pair of NASA science probes on their way to the moon.

After being delayed two days by poor weather and to review technical data after Thursday’s launch scrub, the 124-tall rocket bolted off its seaside pad at 9:08 a.m. EDT on Saturday, darting through partly cloudy skies as it headed into orbit.The Gravity Recovery and Interior Laboratory (GRAIL) mission was developed with scientists at the Massachusetts Institute of Technology. The mission'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," NASA explains. "As a secondary objective, GRAIL will extend knowledge gained from the Moon to the other terrestrial planets."

The satellite probes were launched on the second try, after an initial launch date was scratched because of high winds, Reuters reports. The probes will shoot out more than 930,000 miles into space, to the point where the gravitational pull from the earth and the sun become equal, then slowly drift toward the moon by the very end of the year.The moon's lumpy gravity field will cause slight differences in the force of gravity on the two probes, which will orbit the moon in single file, causing them to move closer or farther from each other. Monitoring the distance between them will produce lunar gravity maps with at least 100 times the resolution of previous measurements, including maps made by Japan's Kaguya mission.