NASA has sent back its first footage of the 'dark' side of the moon, the one that is not visible from the Earth. The footage shows a journey from the north to the south pole of the moon, revealing huge craters caused by asteroid and comet impacts billions of years ago, the Daily Mail reported.

"It's very rugged and covered with impact craters from asteroids that hit the moon's surface," said Maria Zuber, Nasa's principal investigator on Grail.

In the video, the North Pole of the Moon can be seen at the top of the screen as the spacecraft flies toward the lunar South Pole.

The side explored shows the moon being 'tidally locked' to Earth, so one side always faces away from us.

It's the first video from the two probes - named 'Ebb' and 'Flow' - but several others will be sent back.

One of the biggest features spotted on the lower third of the Moon in the video is the Mare Orientale, a 560 mile-wide impact basin that straddles both the Moon's near and far side.

Near the bottom of the screen, the video shows the 93-mile-wide Drygalski crater - recognisable from the unique star-shaped formation in the middle.

The two probes will carry on orbiting the moon in tight formation to measure its gravity and map its little-understood interior.