Cassini

Courtesy of the Jet Propulsion Laboratory

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Circled by distinctive rings and attended by a group of at least 18 moons, Saturn has been called one of the most intriguing planetary realms in the solar system. Its largest moon, Titan, boasts organic chemistry that may hold clues to how life formed on the primitive Earth. So it is that Saturn and Titan was the destination of the Cassini mission, a project by NASA, the European Space Agency and the Italian Space Agency. The U.S. portion of the mission is managed for NASA by the Jet Propulsion Laboratory. Cassini's principal objectives are:

  1. determine the three-dimensional structure and dynamical behavior of the rings;
  2. determine the composition of the satellite surfaces and the geological history of each object;
  3. determine the nature and origin of the dark material on Iapetus' leading hemisphere;
  4. measure the three-dimensional structure and dynamical behavior of the magnetosphere;
  5. study the dynamical behavior of Saturn's atmosphere at cloud level;
  6. study the time variability of Titan's clouds and hazes; and,
  7. characterize Titan's surface on a regional scale.

Cassini was launched in October 1997 atop a Titan IV-Centaur rocket from Cape Canaveral, Florida. Cassini first executed two gravity-assist flybys of Venus, then one each of the Earth and Jupiter to send it on to arrive at Saturn in July 2004. Upon reaching Saturn, Cassini will swing close to the planet -- to an altitude only one-sixth the diameter of Saturn itself -- to begin the first of some five dozen orbits during the rest of its four-year mission. In late 2004, the spacecraft released the European-built Huygens probe for its descent of up to two-and-a-half hours through the dense atmosphere of Saturn's moon Titan. The instrument-laden probe beans its findings to the Cassini orbiter to be stored and finally relayed back to Earth. During the course of the Cassini orbiter's mission, it performed some three dozen close flybys of particular bodies of interest -- including more than 30 encounters of Titan and at least four of selected icy satellites of greatest interest. In addition, the orbiter will make at least two dozen more distant flybys of the Saturian moons. Cassini's orbits will also allow it to study Saturn's polar regions in addition to the planet's equatorial zone.

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Views of Cassini & Huygens

Cassini (1997) (GIF, 87K)
This artist's rendering depicts the NASA/JPL Cassini spacecraft in orbit around ringed Saturn (lower right background). At the lower left, the European Space Agency's Huygens probe descends to the surface of Saturn's moon Titan (in foreground). (Courtesy NASA/JPL)

Huygens (GIF, 75K)
This artist's rendering shows the European Space Agency's Huygens probe descending into the atmosphere of Saturn's moon Titan after being released by NASA's Cassini spacecraft. (Courtesy ESA)

Huygens (GIF, 80K)
This artist's rendering shows the European Space Agency's Huygens probe descending into the atmosphere of Titan with Saturn in the background. (Courtesy ESA)

Huygens on Titan's Surface (GIF, 58K)
This artist's rendering shows the Huygens probe on the surface of Titan. (Courtesy ESA)

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Calvin J. Hamilton
tude only one-sixth the diameter of Saturn itself -- to begin the first of some five dozen orbits during the rest of its four-year mission. In late 2004, the spacecraft will release the European-built Huygens probe for its descent of up to two-and-a-half hours through the dense atmosphere of Saturn's moon Titan. The instrument-laden probe will beam its findings to the Cassini orbiter to be stored and finally relayed back to Earth. During the course of the Cassini orbiter's mission, it will perform some three dozen close flybys of particular bodies of interest -- including more than 30 encounters of Titan and at least four of selected icy satellites of greatest interest. In addition, the orbiter will make at least two dozen more distant flybys of the Saturian moons. Cassini's orbits will also allow it to study Saturn's polar regions in addition to the planet's equatorial zone.

Views of Cassini & Huygens

Cassini Cassini Orbiter and Huygens Probe aboard the Titan IV
At Launch Complex 40 on Cape Canaveral Air Station, the Mobile Service Tower has been retracted away from the Titan IVB/Centaur carrying the Cassini spacecraft. The launch vehicle, Cassini spacecraft and attached Centaur stage encased in a payload fairing, altogether stand about 183 feet tall; mounted at the base of the launch vehicle are two upgraded solid rocket motors. (Courtesy Kennedy Space Center)

Cassini Launch Launch of Cassini Orbiter
A seven-year journey to the ringed planet Saturn begins with the liftoff of a Titan IVB/Centaur carrying the Cassini orbiter and its attached Huygens probe. Launch occurred at 4:43 a.m. EDT, October 15, 1997 from Launch Complex 40 on Cape Canaveral Air Station. (Courtesy Kennedy Space Center)

Cassini Orbiter Cassini Orbiter and Huygens Probe aboard the Titan IV
After a 2.2-billion mile journey that will include two swingbys of Venus and one of Earth to gain additional velocity, the Cassini spacecraft will arrive at Saturn in July 2004. The orbiter will circle the planet for four years, its complement of 12 scientific instruments gathering data about Saturn's atmosphere, rings and magnetosphere and conducting closeup observations of the Saturnian moons. Huygens, with a separate suite of six science instruments, will separate from Cassini to fly on a ballistic trajectory toward Titan, the only celestial body besides Earth to have an atmosphere rich in nitrogen. Scientists are eager to study further this chemical similarity in hopes of learning more about the origins of our own planet Earth. Huygens will provide the first direct sampling of Titan's atmospheric chemistry and the first detailed photographs of its surface. (Courtesy Kennedy Space Center)

Cassini Cassini (1997)
This artist's rendering depicts the NASA/JPL Cassini spacecraft in orbit around ringed Saturn (lower right background). At the lower left, the European Space Agency's Huygens probe descends to the surface of Saturn's moon Titan (in foreground). (Courtesy NASA/JPL)

Huygens Huygens
This artist's rendering shows the European Space Agency's Huygens probe descending into the atmosphere of Saturn's moon Titan after being released by NASA's Cassini spacecraft. (Courtesy ESA)

Huygens Huygens
This artist's rendering shows the European Space Agency's Huygens probe descending into the atmosphere of Titan with Saturn in the background. (Courtesy ESA)

Huygens Huygens on Titan's Surface
This artist's rendering shows the Huygens probe on the surface of Titan. (Courtesy ESA)

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