- Associated Press - Friday, September 9, 2011

CAPE CANAVERAL, FLA. (AP) - NASA will try again Friday to send a pair of spacecraft to the moon.

Thursday’s launch attempt was called off because of high wind. More bad weather is expected Friday. Launch time is 8:33 a.m.

The twin satellites, named Grail-A and Grail-B, will spend several months orbiting the moon. Scientists will measure the entire gravity field of the moon by keeping precise track of the distance between the two probes. They hope to figure out what’s beneath the moon’s surface, all the way down to the core.

Grail stands for Gravity Recovery and Interior Laboratory.

None of the world’s previous 109 moon missions has been dedicated to lunar gravity like Grail. This mission costs $496 million.