Frank images: The discovery suggests that the new moon (indicated by a red box) along with its neighbours Methone and Pallene, may form part of a larger group of moons in this region.

Credit: NASA

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SYDNEY: The Cassini spacecraft has detected a new moon orbiting Saturn, bringing the remarkable total of rocky or icy satellites to 60. Researchers have provisionally called it 'Frank'.

"I was looking at images of the region near the Saturnian moons Methone and Pallene and something caught my eye," said Cassini team scientist and discoverer of the moon, Carl Murray from Queen Mary, University of London in England.

Interplanetary detectives

The newly-discovered moon first appeared as a very faint smear in images snapped of the Saturnian ring system by the U.S. space agency NASA probe in May 2007. Following that initial detection, Cassini project scientists played interplanetary detective, searching for clues of the new moon in the voluminous library of photographs that Cassini has captured to date.

The legwork paid off, as they were able to locate numerous additional faint images of the moon from images as far back as 2004.

"With these new data sets we were able to establish a good orbit for the new moon," said Murray. "Knowing where the moons are at all times is important to the Cassini mission for several reasons."

One of the most important reasons for Cassini to chronicle these previously unknown space rocks is so the spacecraft itself does not run into them. Another reason is each discovery helps provide a better understanding about how Saturn's ring system and all its billions upon billions of parts work and interact together.

Furthermore, a discovery of a moon is important because with this new knowledge, the Cassini mission planners and science team can plan to perform science experiments during future observations if and when the opportunity presents itself.

Cassini scientists believe 'Frank' - the working name affectionately given to the moon until another more appropriate one is found and proosed to the International Astronomical Union, which rules on such names - is about 2 km wide and, like so many of its neighbours, is made mostly of ice and rock. The moon's location in the Saturnian sky is between the orbits of Methone and Pallene, themselves discovered in 2004.

See a NASA movie of 'Frank' orbiting Saturn here.

“It is amazing to think that when Cassini embarked upon its epic journey to Saturn in 1997, we only knew about 18 of its moons," commented Keith Mason, CEO of Britain's Science and Technology Facilities Council. "Since then, through observations from ground based telescopes and the Cassini spacecraft, a further 42 have been identified”

"Each and every new discovery adds another piece to the puzzle and becomes another new world to explore," added Murray.

He and his colleagues may get the chance to explore 'Frank' in December 2009 when the Cassini spacecraft's trajectory will put it within 11,700 km of the celestial object.