Data sent back by the Huygens space probe from the Saturnian moon Titan show a frozen, orange world shrouded in a methane-rich haze with dark ice rocks dotting a riverbed-like surface the consistency of wet sand.

The Huygens probe, part of a $3 billion joint mission involving NASA and the European and Italian space agencies, made its pioneering descent to Titan on Friday, sending back readings on the moon?s atmosphere, composition and landscape.

Slowed by parachutes, Huygens took more than two hours to float to the icy surface, where it defied expectations of a quick death and continued to transmit for at least two hours. Along with scientific instruments that measure the components of Titan?s atmosphere, Huygens carried a sound recorder and lamp to look for signs of surface liquid.

One reading from an instrument suggested that the moon?s surface was the consistency of wet sand or clay.

?We think this is a material which may have a thin crust, followed by a region of relatively uniform consistency?, John Zarnecki, the scientist in charge of experiments on Titan?s surface said from the control center in Germany. One of his colleagues suggested another analogy: creme brulee. ?But I don?t suppose that will be appearing in any of our papers?, he said.

Titan, believed to be the only moon in the solar system with an atmosphere, is larger than the planet Mercury. Scientists believe a study of the icy moon could yield clues about how life developed on Earth. One of the mysteries of Titan is the amount of methane that surrounds it, prompting speculation that there might be oceans of the compound on its surface or below.

Some have also questioned whether the impact of a meteorite - or some other event ? could have thrown off enough heat to liquefy water on Titan, where the surface is now an extreme cold measured at minus 292 F.

Other rock-sized objects photographed in an apparent flow channel on the gold-orange surface of Titan measured appear to frozen blocks of water ice, Tomasko said, although he cautioned more study was needed.

?We just don?t have the answers to many of the questions you can think to ask?, he said. ?Given a little bit of time we will mine (the data) for a new understanding of this mysterious world that has been veiled from our view for so long.?

The mass spectrometer onboard Huygens, a complex instrument designed to analyze molecules in the atmosphere of Titan and on its surface, picked up evidence of a thick cloud of methane about 11-12 miles above the surface. Once on the surface, a heated tube from the craft showed surface material evaporating and producing more methane.

Kevin KROLICKI