NASA launches twin satellites bound for moon

This framegrab image from NASA-TV shows the twin GRAIL satellites atop a United Launch Alliance Delta II rocket as they launch from the launch pad at the Cape Canaveral Air Force Station. NASA is sending the probes on a long, roundabout trip to the moon. It will be the first lunar mission devoted to studying the insides of the moon. Photo: AP

Twin satellites blasted off aboard a rocket Saturday on a mission to unveil the inner secrets of the moon, the US space agency NASA said.

The Grail spacecraft launch at 9.08 am aboard a Delta II rocket from an Air Force base adjacent to NASA’s facilities at Cape Canaveral, Florida.

The blastoff had been postponed twice due to bad weather on Thursday and Friday.

The two small Grail spacecraft - which are about the size of washing machines - will fly in formation above the moon’s surface to map its gravity.

“Trying to understand how the moon formed, and how it evolved over its history, is one of the things we’re trying to address with the Grail mission,” said researcher Maria Zuber of the Massachusetts Institute of Technology.

By measuring variations in gravity across the moon’s surface over three months, scientists hope to learn how the interior formed, which should also provide general clues about how rocky planets form, Ms. Zuber said.