The images began arriving at the National Aeronautics and Space Administration's Deep Space Network tracking station in Madrid, Spain, at 0125 GMT, Wednesday, the laboratory said.

"Numerous images, perhaps as many as 500, were taken by the visible light camera," the NASA statement read.

"The flyby was by far the closest any spacecraft has ever come to Titan," a moon "perpetually drenched in a thick blanket of smog," the statement added.

Cassini-Huygens is the first man-made object to orbit the ringed planet, the sixth from the Sun and second in size after Jupiter.

Titan, the only moon in the solar system with an atmosphere, "is a cosmic time capsule that offers a look back in time to see what Earth might have been like before the appearance of life," NASA said.

At the closest point of the space probe's encounter with Titan, at 1644 GMT Tuesday, the craft was travelling only 1,200 kilometers (750 miles) above the moon, "almost grazing the outer atmosphere" as it raced past at 21,800 kilometers per hour (13,625 miles per hour), the European Space Agency said in an earlier press release.

To travel the 2.1 billion kilometers (1.3 billion miles), the image-bearing signal from Cassini-Huygens takes about one hour and 14 minutes.

Cassini project engineers "will continue to keep a close watch on a rainstorm in Spain, which may interrupt the flow of data from the spacecraft," NASA said.

The craft comprises a US-built orbiter, Cassini, and a European-built probe, Huygens.

The Huygens probe will be released on December 24 and descend to Titan on January 14 "to collect data and touch down on the surface," NASA said.

Cassini-Huygens went into orbit around Saturn on June 30, culminating a seven-year, 3.5 billion-kilometer (2.2 billion-mile) voyage.

Tuesday's flyby was aimed at picking up data for that operation, including radar mapping of the moon's surface, and images and analysis of its gassy atmosphere.

The 3.2-billion-dollar mission is a joint project of NASA, which is providing 2.6 billion dollars of the cost, and ESA and the Italian Space Agency (ISA).

ISA supplied the probe's high-gain antenna which channels all communications with Earth.

At 1030 GMT on Friday, Cassini-Huygens will come within 246,000 kms (153,000 miles) of Tethys, an icy ball that orbits Saturn at a distance of 295,000 kms (185,000 miles).

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