US: The NASA spacecraft Cassini, which is carrying a European Space Agency probe, cut off communications with controllers on Monday as it prepared to peer beneath a veil of smog shrouding Saturn's moon, Titan.
Cassini was set to pass within 1,200 kms of Titan's surface at yesterday evening, in the closest pass ever to the mysterious icy moon, whose atmosphere scientists have likened to a primordial Earth.
Cassini will snap infra red and radar images 100 times sharper than any taken so far of Titan, said scientists at NASA's Jet Propulsion Laboratory in Pasadena, California.
Carrying the European Space Agency probe called Huygens, Cassini was expected to resume contact with NASA controllers last night.
It will download data and images collected during its pass near Titan - one of 45 planned for the spacecraft's four-year tour of Saturn and its moons.
Titan is the only known moon with an atmosphere.
It is believed to have oceans of liquid methane and ethane on its frozen surface and a nitrogen-rich atmosphere that may hold clues to how Earth's atmosphere evolved.
"What we've got is a very primitive atmosphere that has been preserved for 4.6 billion years. Titan gives us the chance for cosmic time travel . . . going back to the very earliest days of Earth when it had a similar atmosphere," said Mr Toby Owens, principal scientist at the Jet Propulsion Laboratory.
In January, Cassini is expected to drop off the Huygens probe.
If it survives a parachute-assisted descent through Titan's atmosphere, the Huygens probe is expected to transmit data for several minutes before freezing in temperatures of -179°Celsius, or sinking beneath a lake of methane.
Little is known about Titan's surface and the first hazy images returned by Cassini in July gave little indication of what Huygens may find.
"On this pass we are looking at the area of Titan where the probe will look in much more detail" with photos that can pick out features the size of a football field, said Earl Maize, deputy programme manager for the Cassini-Huygens mission.
Scientists do not expect to find signs of life but are interested in chemical reactions taking place in a landscape they theorize looks like a melted ice cream sundae.
"No primordial soup but maybe primordial ice cream," Mr Owens said.
- (Reuters)