The Cassini Mission to Saturn at a Glance

Details of the Cassini-Huygens mission to Saturn and its moon Titan:

SATURN: Planet second in size to Jupiter with a diameter of 74,898 miles. Mean distance from sun is 890 million miles. Has seven rings of ice and rock particles named “A” to “G” with 31 known moons. Visited by Pioneer 11 (1979), Voyager 1 (1980), Voyager 2 (1981).

TITAN: Largest Saturnian moon, bigger than planets Mercury and Pluto. Believed to harbor organic compounds similar to those that predated life on Earth. Has a hazy nitrogen-rich atmosphere with about 6 percent methane, 1 1/2 times thicker than Earth’s, along with possible ethane-methane seas or lakes. Surface temperature is minus 290 degrees Fahrenheit.

CASSINI ORBITER: Launched Oct. 15, 1997. Spacecraft is 22 feet long, 13.1 feet wide and weighs 12,593 pounds loaded with fuel and Huygens probe. Makes electricity with nuclear power. Will make 76 orbits of Saturn over four years; 52 close encounters with seven moons.

HUYGENS PROBE: Wok-shaped spacecraft is 8.9 feet in diameter and 705 pounds. Will be released from Cassini on Dec. 24 and enter Titan’s atmosphere on Jan. 14. Will provide up to 2 1/2 hours of science observations during descent by parachute and up to 30 minutes of surface observations.

MISSION COST: $3.3 billion, shared by National Aeronautics and Space Administration, European Space Agency, Italian Space Agency.