Twin NASA spacecraft blast off to study moon

CAPE CANAVERAL, Fla. (AP) ? NASA is headed back to the moon.

The space agency launched a set of twin spacecraft from Cape Canaveral on Saturday, after a two-day delay. They’re called Grail-A and Grail-B, short for Gravity Recovery and Interior Laboratory.

The Grail twins won’t reach the moon until year’s end. They’ll go into orbit around the moon and chase each other in circles. Scientists will monitor the changing distance between the two craft. That way, they can measure the entire gravitational field of the moon.

NASA chose a small unmanned rocket for Grail to save money ? the Delta II. That’s why it’s taking nearly four months to get to the moon. It took the Apollo astronauts three days, four decades ago.

The mission costs $496 million.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP’s earlier story is below.

CAPE CANAVERAL, Fla. (AP) ? NASA’s newest moon probes are still on Earth.

The launch countdown got all the way down to the four-minute mark Saturday morning. But high wind prevented the unmanned rocket from blasting off on the day’s first opportunity. NASA has one more chance to get the twin spacecraft flying Saturday at 9:08 a.m. Otherwise, that’s it until Sunday.

This is the third launch delay for the $496 million Grail mission. Thursday’s try was put off by high wind. Rocket concerns spoiled Friday’s attempt.

The twin Grail spacecraft will circle the moon and measure its gravity.