Cassini is set to pass within 745 miles (1,200 kms) of Titan's surface at about 12:45 p.m. (18:45 GMT) Tuesday, in the closest pass ever to the mysterious icy moon, whose atmosphere scientists have likened to a primordial Earth.
Cassini will snap infrared and radar images 100 times sharper than any taken so far of Titan, said scientists at NASA's Jet Propulsion Laboratory in Pasadena, California.
In January, Cassini is expected to drop off the Huygens probe. If it survives a parachute-assisted descent through Titan's atmosphere, Huygens is expected to transmit data for several minutes before freezing in temperatures of -290 degrees F (-179C), or sinking beneath a lake of methane.
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," Owens said.
The encounter will include many firsts. A few highlights include:
The highest-resolution ever images of Titan's surface
The first high-resolution compositional maps of Titan's surface
The first Synthetic Aperture Radar images of Titan's surface
The first direct measurements of the composition of Titan's atmosphere
