The unmanned Cassini spacecraft, after completing two passes in the vast, unexplored area between Saturn's rings has discovered not much else there, researchers at NASA said. 

Scientists have been surprised to find that not all that much -- not even space dust -- lies between Saturn's iconic rings.

"The region between the rings and Saturn is 'the big empty,' apparently," said Cassini Project Manager Earl Maize of NASA's Jet Propulsion Laboratory in Pasadena, California, after the probe's first pass.

The rings themselves are made of fast-moving particles of ice and space debris.

The 22-foot-tall (6.7 meter) Cassini spacecraft launched in 1997 and began orbiting Saturn in 2004.

Cassini made a first pass to explore what lies between the rings in late April and a second one on May 2, at a speed of about 77,000 miles per hour relative to the planet.

The gap between the rings and the top of Saturn's atmosphere is about 1,500 miles (2,400 kilometers).

Cassini is expected to make a total of 22 dives between the rings and the planet before making a death plunge into the gas giant in September.

Cassini is a 20-year-old joint mission of NASA, the European Space Agency and the Italian Space Agency.

source: AFP