NASA launches twin satellites to study insides of moon

“I could hardly be happier,” said the lead scientist, Maria Zuber. After two days of delays and almost another, “I was trying to be as calm as I could be.”

NASA launched the near identical probes – named Grail-A and Grail-B – aboard a relatively small Delta II rocket to save money. It will take close to four months for the spacecraft to reach the moon, a long, roundabout journey compared with the zippy three-day trip of the Apollo astronauts four decades ago.

Grail-A popped off the upper stage of the rocket exactly as planned 1 1 / 2 hours after liftoff, followed eight minutes later by Grail-B. Both releases were seen live on NASA TV thanks to an on-board rocket camera, and generated loud applause in Launch Control.

The spacecraft are travelling independently to the moon, with A arriving on New Year’s Eve and B on New Year’s Day.

Once they were safely on their way, Ms. Zuber announced a contest for schoolchildren to replace the “working-class names” of Grail-A and Grail-B.

“Grail, simply put, is a journey to the centre of the moon,” said Ed Weiler, head of NASA’s science mission directorate, borrowing from the title of the Jules Verne science fiction classic, “Journey to the Centre of the Earth.”